JP2003137513A - Hydrogen peroxide production method - Google Patents

Abstract

(57) [Problem] To provide a method for efficiently producing hydrogen peroxide. SOLUTION: In the presence of a specific imide compound, a step of bringing a substrate (primary or secondary alcohol) into contact with oxygen (reaction step 21); Separating a second component having a lower hydrogen peroxide content than the first component by distillation (first distillation step 22), and further distilling a component containing hydrogen peroxide (second distillation). Step 23), a step of separating by-products (extraction step 27 and third distillation step 28), and a step of regenerating the substrate (alcohol regeneration step 24) produce hydrogen peroxide efficiently. The regenerated alcohol is recycled to the reaction process.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oxidizing agent, a bleaching agent,
The present invention relates to a method for producing hydrogen peroxide, which is useful as a disinfectant and a germicide. More specifically, it relates to a method for efficiently producing hydrogen peroxide from alcohol through a series of processes in the presence of a specific oxidation catalyst.

[0002]

2. Description of the Related Art As an industrial production method of hydrogen peroxide, for example, (1) an ammonium hydrogensulfate solution is prepared from sulfuric acid and ammonia, an electrode promoter is added to this solution, electrolysis is performed, and anodic oxidation is performed. A method of producing ammonium peroxodisulfate and adding hydrogen peroxide to the obtained ammonium peroxodisulfate to obtain hydrogen peroxide by vacuum distillation, (2) 2-ethylanthraquinol in the absence of a catalyst Anthraquinol compounds such as the above, a method of oxidizing alcohols such as isopropanol and 1-phenylethanol (methylbenzyl alcohol), and (3) a method of directly oxidizing hydrogen in the presence of a catalyst are known.

The method (1) is complicated in process and is disadvantageous in cost, and the method (3) has not yet been industrialized at the research stage. Therefore, in general, the method (2),
Particularly, hydrogen peroxide is produced by a method of autoxidizing an anthraquinol compound in the absence of a catalyst. However, according to the method (2), not only hydrogen peroxide cannot be efficiently produced, but also it is difficult to efficiently recover the produced hydrogen peroxide.

On the other hand, in WO00 / 46145, a specific imide compound (particularly N-hydroxyphthalimide) is used as an oxidation catalyst, and a primary or secondary alcohol (for example, benzhydrol, cyclohexanol, 1-phenyl) is used. A method for producing hydrogen peroxide by reacting oxygen with (for example, ethanol and 2-octanol) is disclosed. In this document, reaction products (hydrogen peroxide,
Aldehyde or ketone) in a conventional manner (filtration, concentration,
It is disclosed that it can be easily separated and purified by a separation means such as distillation, extraction, crystallization, recrystallization, column chromatography). It is also described that an aldehyde or ketone may be converted into a primary or secondary alcohol by a conventional reduction method and reused as a substrate.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method capable of efficiently producing hydrogen peroxide.

Another object of the present invention is to provide a method capable of industrially producing hydrogen peroxide with a simple operation by a series of processes.

[0007]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned objects, the present inventors have found that a specific imide compound is used as an oxidation catalyst to convert a primary or secondary alcohol into oxygen. When contacted and oxidized, hydrogen peroxide is efficiently produced, and further components containing hydrogen peroxide produced from the reaction mixture are separated (especially by distillation), and alcohol is regenerated and regenerated from the by-produced ketone or aldehyde. The present invention was completed by finding that hydrogen peroxide can be efficiently recovered by recycling the alcohol and the oxidation catalyst.

That is, the production method of the present invention is represented by the following formula (I):

[0009]

[Chemical 3]

(In the formula, X represents an oxygen atom or an —OR group (in the formula, R represents a hydrogen atom or a protective group of a hydroxyl group))
A method for producing hydrogen peroxide by reacting a primary or secondary alcohol as a substrate with oxygen using an oxidation catalyst having an imide skeleton represented by
(A) a reaction step of contacting the substrate with oxygen in the presence of the oxidation catalyst, and (B) a first component containing at least hydrogen peroxide from the reaction mixture obtained in the reaction step (A). A separation step for separating a second component having a lower hydrogen peroxide content than the first component, and (B) at least hydrogen peroxide from the reaction mixture obtained in the reaction step (A). And a separation step of separating a first component containing a hydrogen peroxide and a second component having a lower hydrogen peroxide content than the first component; A step of regenerating a primary or secondary alcohol from a second component and recycling to the reaction step (A), and (D) a reaction mixture or a reaction mixture contained in the first or second component and reacting If necessary, the oxidation catalyst used for And, a step of recycling the reaction step (A). In the above method, the reaction may be carried out in the presence of a reaction solvent, and the first component containing hydrogen peroxide and the second component containing the reaction solvent and the oxidation catalyst may be separated by distillation. The reaction may be carried out in a homogeneous system while suppressing the precipitation of solids, and the first component and the second component may be separated in the separation step. Primary or secondary alcohols, by-produced ketones and aldehydes, and reaction solvents having a boiling point higher than that of hydrogen peroxide may be used. The alcohol may be regenerated by subjecting the first or second component, which does not contain an oxidation catalyst and contains by-produced ketone and aldehyde, to a reduction reaction. The substrate is
It may be a secondary alcohol (eg cycloalkanol or aryl alcohol).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the accompanying drawings as needed.

The method of the present invention comprises at least the following (A) reaction step, (B) separation step, (C) alcohol regeneration step, and (D) oxidation catalyst regeneration step.

[(A) Reaction Step] In the reaction step,
In the presence of an oxidation catalyst (catalyst system optionally containing a cocatalyst) composed of a specific imide compound, a primary or secondary alcohol that is a substrate is brought into contact with oxygen to give a desired product, peroxidation. Hydrogen is generated and is the first substrate
Aldehydes or ketones corresponding to the secondary or secondary alcohols are produced as by-products.

(Oxidation catalyst) The oxidation catalyst is represented by the formula (I)
A compound having an imide skeleton represented by (hereinafter sometimes simply referred to as an imide compound) can be used.

[0015]

[Chemical 4]

(In the formula, X represents an oxygen atom or an —OR group (in the formula, R represents a hydrogen atom or a protecting group for a hydroxyl group))
Examples of the protective group for the hydroxyl group represented by R include alkyl groups (for example, C _1-6 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, isopentyl, and hexyl groups, Preferably C _1-4 alkyl group), acyl group (eg C _2-5 acyl group such as acetyl, propionyl, butyroyl group), alkoxycarbonyl group (eg C _2-5 alkoxy such as methoxycarbonyl, ethoxycarbonyl group) Carbonyl group) and the like. Particularly, an alkyl group and an acyl group are preferable.

In the above formula (I), the nitrogen atom N
The bond between X and X is a single bond or a double bond.

A preferred oxidation catalyst is represented by the following formula (II).

[0019]

[Chemical 5]

(In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group or an acyl group. R ¹ and R ² may be bonded to each other to form a double bond or an aromatic or non-aromatic ring.
^The aromatic or non-aromatic ring formed by ¹ and / or R ² may have at least one imide skeleton represented by the above formula (I). X is the same as above) In the compound of the formula (II), the halogen atom in the substituents R ¹ and R ² includes iodine, bromine, chlorine and fluorine. Alkyl groups include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-
Butyl, t-butyl, pentyl, hexyl, heptyl,
Octyl, straight-chain or branched-chain alkyl group (preferably C _1-6 alkyl groups, especially C _{1 -4} alkyl group) having about 1 to 10 carbon atoms such as decyl groups include.

The aryl group includes a phenyl group and a naphthyl group, and the cycloalkyl group includes a C _3-10 cycloalkyl group such as a cyclopentyl, cyclohexyl and cyclooctyl group. Alkoxy groups include, for example, C _1-10 alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, t-butoxy, pentyloxy and hexyloxy groups,
Preferably, a C _1-6 alkoxy group, especially a C _1-4 alkoxy group is included.

The alkoxycarbonyl group includes, for example, a carbon of an alkoxy moiety such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, t-butoxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl group. An alkoxycarbonyl group having a number of about 1 to 10 (preferably C _1-6 alkoxy-carbonyl group, more preferably C _1-4 alkoxy-
A carbonyl group) is included.

As the acyl group, for example, formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl group and the like having 1 to 6 carbon atoms can be mentioned.
A degree of acyl group can be exemplified.

The substituents R ¹ and R ² may be the same or different. Further, in the above formula (II), R ¹ and R ²
May combine with each other to form a double bond or an aromatic or non-aromatic ring. The preferred aromatic or non-aromatic ring is a 5- to 12-membered ring, especially a 6- to 10-membered ring, which may be a heterocyclic ring or a condensed heterocyclic ring, but is often a hydrocarbon ring. Such a ring includes, for example, a non-aromatic alicyclic ring (a cycloalkane ring which may have a substituent such as a cyclohexane ring, a cycloalkene ring which may have a substituent such as a cyclohexene ring). Ring), a non-aromatic bridged ring (such as a bridged hydrocarbon ring which may have a substituent such as a 5-norbornene ring),
Included are aromatic rings (including condensed rings) that may have a substituent such as a benzene ring and a naphthalene ring. The ring is
Often composed of aromatic rings.

The ring has an alkyl group, a haloalkyl group,
Hydroxyl group, alkoxy group, carboxyl group, alkoxycarbonyl group, acyl group, nitro group, cyano group,
It may have a substituent such as an amino group and a halogen atom.

The double bond, aromatic ring or non-aromatic ring formed by combining R ¹ , R ² or R ¹ and R ² with each other is represented by the above formula (I). It may have at least one (usually 1 or 2) imide skeleton. For example, when R ¹ or R ² is an alkyl group having 2 or more carbon atoms, the imide skeleton represented by the above formula (I) containing two adjacent carbon atoms among the carbon atoms constituting the alkyl group is It may be formed. When R ¹ and R ² are bonded to each other to form a double bond, the imide skeleton represented by the formula (I) may be formed by including the double bond. Further, in the case where R ¹ and R ² are bonded to each other to form an aromatic or non-aromatic ring, the carbon atoms forming the ring include two carbon atoms adjacent to each other and have the above formula (I ) The imide skeleton shown by may be formed.

Preferred imide compounds include compounds represented by the following formula.

[0028]

[Chemical 6]

(In the formula, R ^{3 to} R ⁶ are the same or different,
A hydrogen atom, an alkyl group, a haloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, an acyl group, a nitro group, a cyano group, an amino group and a halogen atom are shown. In R ^{3 to} R ⁶ , adjacent groups may be bonded to each other to form an aromatic or non-aromatic ring. A represents a methylene group or an oxygen atom. R ¹ , R ² and X are the same as above) In the substituents R ^{3 to} R ⁶ , an alkyl group, an alkoxy group,
Examples of the alkoxycarbonyl group, the acyl group and the halogen atom are the same groups or atoms as those described above [for example, having 1 to 6 carbon atoms].
Alkyl group, haloalkyl group having about 1 to 4 carbon atoms such as trifluoromethyl group, alkoxy group having about 1 to 4 carbon atoms, lower alkoxycarbonyl group having about 1 to 4 carbon atoms, and about 1 to 6 carbon atoms Acyl group, halogen atom such as fluorine, chlorine and bromine atom]. Substituent R ³
In most cases, R ⁶ to R ⁶ are usually a hydrogen atom, a lower alkyl group having about 1 to 4 carbon atoms, a carboxyl group, a nitro group, or a halogen atom. Among the substituents R ³ to R ^6, as the ring formed by bonding adjacent groups together, wherein R ¹ and R ² are combined can be exemplified the same ring and the ring formed from each other, especially aromatic Alternatively, a non-aromatic 5- to 12-membered ring is preferable.

The imide compounds represented by the formula (I) can be used alone or in combination of two or more.

Examples of the acid anhydride corresponding to the imide compound represented by the above formula (I) include saturated or unsaturated aliphatic dicarboxylic acid anhydrides such as succinic anhydride and maleic anhydride, tetrahydrophthalic anhydride, Hexahydrophthalic anhydride (1,2-cyclohexanedicarboxylic acid anhydride),
1,2,3,4-cyclohexanetetracarboxylic acid 1,
Saturated or unsaturated non-aromatic cyclic polyvalent carboxylic acid anhydrides such as 2-anhydrides (alicyclic polyvalent carboxylic acid anhydrides), bridged cyclic polyvalent carboxylic acids such as hettic anhydride and hymic acid anhydride Anhydrides (alicyclic polycarboxylic acid anhydrides), phthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, nitrophthalic anhydride, trimellitic anhydride,
Aromatic polyvalent carboxylic acid anhydrides such as methylcyclohexene tricarboxylic acid anhydride, pyromellitic dianhydride, mellitic dianhydride, and 1,8; 4,5-naphthalenetetracarboxylic dianhydride are included.

Preferred imide compounds include, for example:
N-hydroxysuccinimide, N-hydroxymaleic acid imide, N-hydroxyhexahydrophthalic acid imide, N, N'-dihydroxycyclohexanetetracarboxylic acid imide, N-hydroxyphthalic acid imide, N-hydroxytetrabromophthalic acid imide , N-hydroxytetrachlorophthalimide, N-acetoxyphthalimide, N-hydroxyhetimide, N-hydroxyhymic acid imide, N-hydroxytrimellitic imide, N, N'-dihydroxypyromellitic imide , N, N′-dihydroxynaphthalene tetracarboxylic acid imide and the like. Particularly preferred compounds include
Cyclic imide compound [N-hydroxyimide compound derived from alicyclic polycarboxylic acid anhydride or aromatic polycarboxylic acid anhydride, for example, aromatic such as N-hydroxyphthalimide, N-acetoxyphthalimide, etc. N-hydroxyimide compounds derived from group polycarboxylic acid anhydrides] are included.

The above-mentioned imide compound can be prepared by a conventional imidization reaction such as the corresponding acid anhydride and hydroxylamine N.
It can be prepared by reacting with H ₂ OH to open the acid anhydride group, and then ring-closing and imidizing.

When such an oxidation catalyst is used,
Hydrogen peroxide can be obtained in high yield simply by contacting the substrate with oxygen.

The amount of the imide compound of formula (I) used is
A wide range can be selected, for example, 0.
000001 mol (0.0001 mol%) to 1 mol (1
00 mol%), preferably 0.00001 mol (0.0
01 mol%) to 0.5 mol (50 mol%), more preferably about 0.0001 mol (0.01 mol%) to 0.4 mol (40 mol%), and 0.0001 mol (0.
In many cases, it is about 01 mol%) to 0.35 mol (35 mol%).

Such an imide compound is prepared, for example, through the following oxidation catalyst production step and, if necessary, hydroxylamine production step.

(Production Step of Oxidation Catalyst) The imide compound is subjected to a conventional imidation reaction, for example, by reacting a corresponding acid anhydride with hydroxylamine NH ₂ OH to open the acid anhydride group and then ring-closing. Then, it can be prepared by imidization. More specifically, when the oxidation catalyst is N-hydroxyphthalimide, phthalic anhydride and hydroxylamine may be used as catalyst raw materials, and the oxidation catalyst may be produced by reactive distillation while removing water produced in the reaction. . The oxidation catalyst can be produced by a conventional method such as a batch system, a semi-batch system or a continuous system.

The obtained oxidation catalyst may be directly used as a catalyst in the catalyst solution preparing step described later. The oxidation catalyst may be separated from the reaction mixture and, if necessary, may be recycled to the reaction system through a regeneration step described later.

The catalyst production process may be carried out in combination with the catalyst regeneration process described later.

(Process for producing hydroxylamine)
Hydroxylamine as an oxidation catalyst raw material can be produced, for example, as follows.

Ammonia (which may be by-produced in the catalyst regeneration step described later) is oxidized with molecular oxygen to generate nitrogen oxides. A platinum-based catalyst is generally used as the catalyst in this oxidation reaction. This nitrogen oxide may be extracted or absorbed with an extraction or absorption solvent (eg water). The extracted nitrogen oxide can be subjected to a hydrogenation reaction with hydrogen to produce hydroxylamine. The reactor for oxidizing ammonia is not particularly limited, but a tube reactor is often used.
A conventional device can be used as a device for extracting nitrogen oxides. As the hydrogenation reaction device, a conventional device such as a stirring tank type device can be used. The reaction can be carried out by a conventional method such as a continuous system, a batch system or a semi-batch system. The obtained hydroxylamine may be used as it is in the oxidation catalyst production step and the catalyst regeneration step described later.

(Cocatalyst) In order to improve the reaction rate and the reaction selectivity, the imide compound of the formula (I) and a cocatalyst may be used in combination to form an oxidation catalyst system.

The cocatalyst includes, for example, (1) a compound having a carbonyl group bonded to an electron-withdrawing group, (2) a metal compound, (3) a group 15 or 16 group of the periodic table bonded to at least one organic group. An organic salt composed of a polyatomic cation or polyatomic anion containing an element and a counter ion (counter ion) is included. These co-catalysts may be used alone or in combination of two or more.

(1) Compound having a carbonyl group to which an electron-withdrawing group is bonded In a compound having a carbonyl group to which an electron-withdrawing group is bonded (hereinafter, may be simply referred to as (1) compound), it is bonded to a carbonyl group. Examples of the electron-withdrawing group include halogen-substituted alkyl groups such as fluoromethyl, trifluoromethyl, and tetrafluoroethyl groups (preferably halogen (especially fluorine atom) -substituted C _1-4.
Alkyl group), phenyl group, fluorophenyl, pentafluorophenyl group and other aryl groups which may be substituted with halogen (preferably halogen (especially fluorine atom))
_Examples thereof include a substituted C _6-10 aryl group.

Typical examples of the compound (1) include di (halogen-substituted C _1-6 alkyl) ketone such as hexafluoroacetone and halogen-substituted C _6-10 such as pentafluorophenyl (methyl) ketone. Aryl (C _1-6 alkyl) ketone, pentafluorophenyl (trifluoromethyl) ketone and other halogen-substituted C _6-
10 aryl (halogen substituted C _1-6 alkyl) ketones, trifluoroacetic acid, good acid be halogen-substituted, such as benzoic acid. The compounds (1) can be used alone or in combination of two or more.

(2) Metal compound As the metal compound, a metal compound containing an element of groups 1 to 15 of the periodic table, for example, a transition metal compound or a boron compound, an element of group 13 of the periodic table (boron B, aluminum A).
1) and the like) are included. These metal compounds may be used alone or in combination of two or more.

Examples of the element of the transition metal include elements of the periodic table group 1 (Li, Na, K, etc.), elements of the periodic table group 2 (Mg, Ca, Sr, Ba, etc.), and elements of the periodic table group 3 (S).
In addition to c and Y, lanthanoid elements such as La, Ce and Sm, actinide elements such as Ac), periodic table group 4 elements (Ti, Zr, Hf etc.), group 5 elements (V, Nb, Ta)
Etc.), periodic table group 6 element (Cr, Mo, W, etc.), periodic table group 7 element (Mn, etc.), periodic table group 8 element (Fe, R
u, Os, etc.), periodic table group 9 element (Co, Rh, Ir, etc.), periodic table group 10 element (Ni, Pd, Pt, etc.), periodic table group 11 element (Cu, Ag, Au, etc.), periodic table 12
Group elements (Zn, etc.), Group 13 elements of the periodic table (B, Al, I
n, etc.), periodic table group 14 elements (Sn, Pb, etc.), periodic table group 15 elements (Sb, Bi, etc.), and the like. Preferred metal elements include transition metal elements (particularly, periodic table 3 to
Group 12 elements) are included. In particular, when combined with an imide compound represented by the above formula (I), elements of Groups 5 to 11 of the Periodic Table, in particular, Group 6 elements (especially Mo), Group 7 elements (especially Mn) and Group 9 elements ( Co) is particularly preferable. The valence of the metal element is not particularly limited, but is often 0 to 6 valence.

The co-catalyst is not particularly limited as long as it contains the above-mentioned elements and has catalytic ability, and examples thereof include simple substances, hydroxides, oxides (including complex oxides), halides (fluorides) of the above-mentioned metal elements. , Chloride, bromide, iodide), oxo acid salt (nitrate, sulfate, phosphate, borate, carbonate, etc.), organic acid salt (acetate, propionate, cyanate,
C _1-30 carboxylates such as naphthenates and stearates), inorganic salts (nitrates, sulfates, phosphates, etc.), coordination compounds (complexes) containing the above metal elements, heteropolyacids or the like. It is often salt.

The ligands forming the complex include alkoxy groups such as OH (hydroxo), methoxy, ethoxy, propoxy and butoxy groups, acyl groups such as acetyl and propionyl, alkoxy groups such as methoxycarbonyl (acetato) and ethoxycarbonyl. Phosphorus such as carbonyl group, acetylacetonato, cyclopentadienyl group, halogen atom such as chlorine and bromine, CO, CN, oxygen atom, H ₂ O (aco), phosphine (for example, triarylphosphine such as triphenylphosphine) Compound, NH
Examples thereof include nitrogen-containing compounds such as ₃ (ammine), NO, NO ₂ (nitro), NO ₃ (nitrato), ethylenediamine, diethylenetriamine, pyridine, and phenanthroline. In the complex or complex salt, the same or different ligands may be coordinated in one kind or two or more kinds.

Preferred complexes include complexes containing the above transition metal elements. The transition metal element and the ligand can be appropriately combined to form a complex, for example, cerium acetylacetonate, cobalt acetylacetonate,
It may be ruthenium acetylacetonate or copper acetylacetonate.

The polyacid forming the heteropolyacid is, for example, an element of Group 5 or 6 of the periodic table, for example, V (vanadic acid), Mo (molybdic acid) and W (tungstic acid).
In many cases, the central atom is not particularly limited. Specific examples of the heteropoly acid include, for example,
Cobalt molybdate, cobalt tungstate,
Examples thereof include molybdenum tungstate, vanadium molybdate, and vanadomolybdophosphate.

Examples of the boron compound include borohydride (eg, borane, diborane, tetraborane, pentaborane, decaborane, etc.), boric acid (orthoboric acid, metaboric acid, tetraboric acid, etc.), borate (eg, borate). , Nickel borate, magnesium borate, manganese borate, etc.), boron oxides such as B ₂ O ₃ , nitrogen compounds such as borazane, borazene, borazine, boronamide, and boronimide, BF ₃ , BCl ₃ , tetrafluoroboro Examples thereof include halides such as acid salts, borate esters (eg, methyl borate, phenyl borate, etc.) and the like.

(3) Organic Salt In the above (3) organic salt, an organic group is bonded to the periodic table 1
Examples of Group 5 elements include nitrogen N, phosphorus P, arsenic As, antimony Sb, and bismuth Bi.
The elements of the group elements include oxygen O, sulfur S, selenium Se,
Tellurium Te etc. can be illustrated. As a preferable element,
N, P, As, Sb, S, and particularly N, P, S
Are preferred.

In the organic salt (3), the periodic table 1 is used.
The organic group bonded to the group 5 or 16 element includes a hydrocarbon group which may have a substituent, a substituted oxy group and the like. Examples of the hydrocarbon group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl,
t-butyl, pentyl, hexyl, octyl, decyl,
A linear or branched aliphatic hydrocarbon group having about 1 to 30 carbon atoms (preferably about 1 to 20 carbon atoms) such as tetradecyl, hexadecyl, octadecyl, allyl and the like (for example, an alkyl group, an alkenyl group and an alkynyl group) Etc.); C3 such as cyclopentyl and cyclohexyl
Alicyclic hydrocarbon groups of about 8 to 8; aromatic hydrocarbon groups of about 6 to 14 carbon atoms such as phenyl and naphthyl. Preferred hydrocarbon groups include an alkyl group having about 1 to 30 carbon atoms, an aromatic hydrocarbon group having about 6 to 14 carbon atoms (particularly, a phenyl group or a naphthyl group), and the like.
The substituted oxy groups include alkoxy groups (C _1-6 alkoxy groups such as methoxy and ethoxy groups), aryloxy groups (C _6-14 aryloxy groups such as phenoxy groups), aralkyloxy groups (benzyloxy groups). Such as C
_6-10 aryl-C _1-4 alkyloxy group) and the like.

Examples of the substituent which the hydrocarbon group may have include a halogen atom, an oxo group, a hydroxyl group, a substituted oxy group (eg, an alkoxy group, an aryloxy group, an acyloxy group, etc.), a carboxyl group, A substituted oxycarbonyl group, a substituted or unsubstituted carbamoyl group,
Cyano group, nitro group, substituted or unsubstituted amino group, alkyl group (for example, alkyl group having 1 to 4 carbon atoms such as methyl or ethyl group), cycloalkyl group, aryl group (for example, phenyl or naphthyl group) , A heterocyclic group and the like can be exemplified.

The polyatomic cation constituting the organic salt (3) is represented by, for example, the following formula (a).

[(R ^a ) _m M] ⁺ (a) (In the formula, M represents an element of Group 15 or Group 16 of the periodic table,
R ^a represents a hydrocarbon or hydrogen atom, R ^a may be the same or different from each other, and at least one R ^a is a hydrocarbon group. Two R ^a's may be bonded to each other to form a ring with the adjacent M, or R ^a and M may form a double bond and may be bonded to another R ^a to form a ring. m represents an integer. ) The above polyatomic cation constitutes an organic salt represented by the following formula (b) together with the counter anion.

[(R ^a ) _m M] ⁺ Y ⁻ (b) (In the formula, Y ⁻ represents a counter anion. M, R ^a and m are the same as above) In the formulas (a) and (b), , Preferred m is 3 or 4.

The hydrocarbon group represented by R ^a may have the above-mentioned substituent, for example.

Examples of the atom or group constituting the counter anion represented by Y include acid groups (for example, halogen atoms such as chlorine atom and bromine atom).

Among the organic salts having the structure represented by the above formula (b), preferable salts include organic ammonium salts, organic phosphonium salts, organic sulfonium salts and the like.

As a typical example of the organic ammonium salt, a quaternary ammonium salt having four hydrocarbon groups bonded to a nitrogen atom (eg, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrahexylammonium salt). Quaternary ammonium chloride such as chloride, trioctylmethylammonium chloride, triethylphenylammonium chloride, tributyl (hexadecyl) ammonium chloride, di (octadecyl) dimethylammonium chloride; tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetra Hexyl ammonium bromide, trioctyl methyl ammonium bromide, triethyl phenyl ammonium Umium bromide, tributyl (hexadecyl) ammonium bromide, quaternary ammonium bromides such as di (octadecyl) dimethylammonium bromide); cyclic quaternary ammonium salts (eg, dimethylpiperidinium chloride, hexadecylpyridinium chloride, methylquinolinium) Such as chloride).

Typical examples of the organic phosphonium salt include tetramethylphosphonium chloride, tetrabutylphosphonium chloride and tributyl (hexadecyl).
Quaternary phosphonium chlorides such as phosphonium chloride and triethylphenylphosphonium chloride; tetramethylphosphonium bromide, tetrabutylphosphonium bromide, tributyl (hexadecyl) phosphonium bromide, quaternary phosphonium bromide such as triethylphenylphosphonium bromide Examples include quaternary phosphonium salts having a hydrocarbon group bonded thereto.

Representative examples of the organic sulfonium salt include sulfonium salts such as triethylsulfonium iodide and ethyldiphenylsulfonium iodide in which three hydrocarbon groups are bonded to sulfur atoms.

On the other hand, the polyatomic anion constituting the organic salt (3) is represented by, for example, the following formula (c).

[0066] _{^{[R b MO 3] q -}} ( wherein, R ^b is, .q indicating a hydrocarbon group or a hydrogen atom is an integer .M is the same) (c) above polyatomic anion Together with the counter cation, an organic salt represented by the following formula (d) is constituted.

Z ^{q +} [R ^b MO ₃ ] q ⁻ (d) (wherein Z represents a counter cation. M, R ^b and q are the same as above) q is an integer, for example, 1 or 2 is there.

Examples of the hydrocarbon group represented by R ^b include the same groups as the above R ^a , as well as resins (polymer chains or branched chains thereof).

In formulas (c) and (d), the preferred M
Includes S, P and the like. When M is S etc., q is 1
And q is 2 when M is P or the like.

Examples of Z include alkali metals such as sodium and potassium; alkaline earth metals such as magnesium and calcium. Preferred Z includes alkali metals. Z ^{q +} may be the polyatomic cation described above.

Examples of the organic salt having the structure represented by the formula (d) include alkyl sulfonates such as methane sulfonate, ethane sulfonate, octane sulfonate and dodecane sulfonate; benzene sulfonate. , P-
Aryl sulfonates which may be substituted with an alkyl group such as toluene sulfonate, naphthalene sulfonate, decylbenzene sulfonate, dodecylbenzene sulfonate; sulfonic acid type ion exchange resin (ion exchanger); phosphone Examples thereof include acid type ion exchange resins (ion exchangers). In particular, an alkyl sulfonate having 6 to 18 carbon atoms and an alkyl-aryl sulfonate having 6 to 18 carbon atoms are often used.

The amount of the co-catalyst used can be selected from a wide range, and for example, 1 × 10 ⁻⁶ mol to 0.
7 mol, preferably 1 × 10 ⁻⁵ mol to 0.3 mol, more preferably about 1 × 10 ⁻⁵ mol to 0.1 mol (10 mol%), and 1 × 10 ⁻⁶ mol to 1 × 10. ^It may be ^-2 mol, particularly about 1 x 10 ^-6 mol to 1 x 10 ^-3 mol.

The promoter is usually 1 to 10000 ppm, preferably 5 to 50 ppm by weight in the liquid phase reaction system.
It can be used at a concentration of about 00 ppm, more preferably about 10 to 3000 ppm.

In particular, the amount of the compound (1) used is, for example, about 0.0001 mol (0.01 mol%) to 1 mol (100 mol%), preferably 0.
01 mol (10 mol%) to 0.7 mol (70 mol%), more preferably 0.05 mol (5 mol%) to 0.
It is about 5 mol (50 mol%).

Of the above-mentioned (2) metal compounds, when a heteropoly acid or a salt thereof is used as a co-catalyst, the substrate 100
0.1 to 25 parts by weight, preferably 0.5
It is about 10 to 10 parts by weight, more preferably about 1 to 5 parts by weight.

The amount of the organic salt (3) used is, for example, 0.0001 mol (0.01 mol%) per mol of the substrate.
-0.7 mol (70 mol%), preferably 0.001 mol (0.1 mol%)-0.5 mol (50 mol%), more preferably 0.002 mol (0.2 mol%)- 0.1
Mol (10 mol%), and 0.005 mol (0.
It is often about 5 mol%) to 0.05 mol (5 mol%). If the amount of the organic salt used is too large, the reaction rate may decrease.

The imide compound represented by the formula (I) or the catalyst system composed of the imide compound (I) and the cocatalyst may be a homogeneous system or a heterogeneous system. May be. Further, the catalyst system may be a solid catalyst in which a catalyst component is supported on a carrier. As the carrier, activated carbon,
Porous carriers such as zeolite, silica, silica-alumina and bentonite are often used. The loading amount of the catalyst component in the solid catalyst is about 0.1 to 50 parts by weight of the imide compound of the formula (I) with respect to 100 parts by weight of the carrier. The amount of the cocatalyst carried is about 0.1 to 30 parts by weight with respect to 100 parts by weight of the carrier.

The catalyst system (catalyst solution) containing the above-mentioned imide compound and, if necessary, a promoter may be prepared, for example, through the following catalyst solution preparation step.

[Catalyst Solution Preparation Step] In the catalyst solution preparation step, in order to adjust the catalyst concentration to a predetermined value, the oxidation catalyst is
The catalyst solution can be prepared by mixing with other components (for example, a substrate such as cycloalkane, a cocatalyst, a solvent, etc.). Each component of the catalyst solution may be completely dissolved or may be a dispersion system.

The ratio of the imide compound of formula (I) to the cocatalyst is, for example, imide compound / cocatalyst = 95/5.
5/95 (molar ratio), preferably 90/10 to 20/8
0 (molar ratio), more preferably 85/15 to 50/5
It is about 0 (molar ratio). Further, the catalyst concentration is adjusted to the above-mentioned catalyst concentration according to the supply amount of the catalyst solution.

The catalyst and / or co-catalyst may be supported on a physically or chemically insoluble carrier and held in the reactor as a fixed bed or a fluidized bed.

The catalyst solution thus prepared is subjected to the oxidation reaction step.

(Primary or Secondary Alcohol) In the present invention, a primary or secondary alcohol is used as a substrate. The primary or secondary alcohol used is 1
Any of a dihydric alcohol, a dihydric alcohol and a polyhydric alcohol may be used, and various alcohols can be used.

Further, the primary or secondary alcohol includes various substituents such as a halogen atom (eg iodine,
Bromine, chlorine and fluorine atoms), oxo group, hydroxyl group, mercapto group, substituted oxy group (eg, alkoxy group, aryloxy group, acyloxy group, etc.), substituted thio group, carboxyl group, substituted oxycarbonyl group, substituted or unsubstituted Substituted carbamoyl group, cyano group, nitro group, substituted or unsubstituted amino group, alkyl group, alkenyl group, alkynyl group, cycloalkyl group, cycloalkenyl group, aryl group (for example, phenyl group, naphthyl group, etc.), aralkyl group, It may have a heterocyclic group or the like. Such primary or secondary alcohols may be used alone or in combination of two or more.

As the primary alcohol, methanol,
Ethanol, 1-propanol, 1-butanol, 2-
Methyl-1 propanol, 1-pentanol, 1-hexanol, 1-octanol, 1-decanol, 1-hexadecanol and the like have about 1 to 30 carbon atoms (preferably about 1 to 20 and more preferably about 1 to 15). ) Saturated or unsaturated aliphatic primary alcohols; cyclopentylmethyl alcohol, cyclohexylmethyl alcohol, 2
A saturated or unsaturated alicyclic primary alcohol having about 3 to 12 membered rings (preferably about 4 to 10 membered rings, more preferably about 4 to 8 membered rings) such as cyclohexylethyl alcohol; benzyl alcohol, 2- Examples thereof include aromatic primary alcohols such as phenylethyl alcohol and 3-phenylpropyl alcohol; and heterocyclic primary alcohols such as 2-hydroxymethylpyridine. Preferred primary alcohols include saturated or unsaturated aliphatic primary alcohols (for example, saturated aliphatic primary alcohols having about 1 to 20 carbon atoms) and the like.

As secondary alcohols, 2-propanol, s-butyl alcohol, 2-pentanol, 3-
Pentanol, 2-hexanol, 2-octanol,
Carbon number 3 such as 4-decanol and 2-hexadecanol
To about 30 (preferably about 3 to 20 and more preferably about 3 to 15) saturated or unsaturated aliphatic secondary alcohols; cyclobutanol, cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol, cyclopenta About 3 to 20 membered ring such as decanol (preferably about 3 to 15 membered ring, more preferably about 5 to 15 membered ring)
Saturated or unsaturated alicyclic secondary alcohols having about 15-membered rings, especially about 5 to 8-membered rings; 1-phenylethanol (methylbenzyl alcohol), 1-phenylpropanol, 1-phenylmethylethanol, benzhydrol And aromatic secondary alcohols such as (diphenylmethanol); heterocyclic secondary alcohols such as 1- (2-pyridyl) ethanol and 2-ethylanthrahydroquinone. Preferred secondary alcohols include saturated alicyclic secondary alcohols such as C _3-8 cycloalkanols and aromatic secondary alcohols such as C _6-14 aryl alcohols.

The (oxygen) reaction is carried out in an oxygen atmosphere. The oxygen source is not particularly limited and may be pure oxygen or oxygen diluted with an inert gas such as nitrogen, helium, argon or carbon dioxide. From the viewpoint of not only operability and safety but also economical efficiency, it is preferable to use air.

When supplying molecular oxygen into the reactor,
After supplying sufficient molecular oxygen in advance, the reaction may be carried out in a closed system, or the molecular oxygen may be continuously circulated. When continuously flowing, the oxygen flow rate is, for example, 0.000 per 1 L of the unit volume of the container of the reactor.
1 to 2 Nm ³ / hour, preferably 0.001 to 1 Nm ³
Per hour. The amount of molecular oxygen supplied to the reactor is
It can be appropriately selected depending on the kind of the substrate and the desired conversion rate, but it is usually 0.1 mol or more, preferably about 0.5 to 10 mol with respect to 1 mol of the substrate, and an excess molecule with respect to the substrate. Often, gaseous oxygen is supplied.

When molecular oxygen is continuously circulated, part or all of the exhaust gas may be reused. in this case,
The reaction heat can be removed by the latent heat of the accompanying steam.

(Reaction Solvent) The reaction of the present invention can be carried out in the presence or absence of an organic solvent inert to the reaction. Examples of the organic solvent include organic acids such as acetic acid and propionic acid; nitriles such as acetonitrile, propionitrile and benzonitrile; amides such as formamide, acetamide, dimethylformamide (DMF) and dimethylacetamide; hexane and octane. Aliphatic hydrocarbons; halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, trifluoromethylbenzene; nitro compounds such as nitrobenzene, nitromethane, nitroethane; esters such as ethyl acetate, butyl acetate; water A mixed solvent thereof and the like can be mentioned. As the solvent, organic acids such as acetic acid, nitriles such as acetonitrile and benzonitrile, halogenated hydrocarbons such as trifluoromethylbenzene, and esters such as ethyl acetate are often used.

In the separation step to be described later, if a solvent having a higher boiling point than the product hydrogen peroxide, the substrate alcohol and the by-produced ketone and aldehyde is used, the high boiling point oxidation catalyst can be efficiently recovered, It is possible to suppress migration of the oxidation catalyst to a component containing by-products such as aldehyde and ketone.

The reaction temperature can be appropriately selected depending on the type of substrate used, and is, for example, 0 to 300 ° C, preferably 20 to 200 ° C, more preferably 30 to 150 ° C. If the reaction temperature is set to 160 ° C. or higher, hydrogen peroxide is easily decomposed.
The reaction often occurs at about 0 ° C (particularly 50 to 100 ° C).

The reaction can be carried out under normal pressure, reduced pressure or increased pressure, and the reaction pressure is usually 0.1 to 100 at.
m, preferably about 1 to 70 atm, more preferably about 3 to 50 atm.

The reaction time (residence time in the flow-type reaction) is, for example, 1 minute to 4 depending on the reaction temperature and pressure.
It can be appropriately selected from the range of 8 hours, preferably 2 minutes to 24 hours, and more preferably 5 minutes to 8 hours.

The reaction of the present invention can be carried out by a conventional method such as a batch system, a semi-batch system or a continuous system. The reaction apparatus is not particularly limited, and a conventional gas-liquid contact reaction apparatus can be used. For example, in order to promote gas-liquid contact, a stirring tank type device equipped with a forced stirring device, a sparger, or a baffle may be used, or a bubble column type device may be used.
Further, the reactor may have multi-stage partition walls, feed nozzles, shelves, packing, etc. inside. One or more reactors may be used, and if multiple devices are used, the devices may be connected in series and / or in parallel.

The reaction mixture may be withdrawn in the liquid phase or the gas phase from the reactor. In particular, when water is present as an impurity in the reaction mixture and the substrate (primary or secondary alcohol) used has a boiling point higher than that of hydrogen peroxide, hydrogen peroxide generation reaction It is advantageous to reduce the water concentration in the liquid phase while withdrawing water, which has undesired effects, together with hydrogen peroxide in the gas phase. Further, since the imide compound is easily hydrolyzed and excess water causes a decrease in catalytic activity, the water content in the reaction mixture is preferably 200 mol or less per 1 mol of the imide group. A reactive distillation apparatus may be used to remove substances such as water which adversely affect the reaction.

In the method of the present invention, hydrogen peroxide is produced by such a reaction. In the above reaction, by-products corresponding to the substrate (aldehydes when the substrate is a primary alcohol, ketones when the substrate is a secondary alcohol) are produced and, for example, peroxides other than hydrogen peroxide are used. Unstable substances such as oxides are produced as by-products. Therefore, in the present invention, from the reaction mixture obtained in the reaction step,
In order to separate hydrogen peroxide efficiently, the reaction mixture is subjected to (B) separation step. [(B) Separation Step] In the separation step, from the reaction mixture obtained in the (A) reaction step, the first component containing at least hydrogen peroxide and the hydrogen peroxide content higher than the first component are contained. Is separated into a second component having a small amount. The reaction mixture usually contains hydrogen peroxide as a product and a first substrate as a substrate.
Or secondary alcohols, by-products such as ketones or aldehydes, oxidation catalyst systems (oxidation catalysts, co-catalysts, derivatives thereof, etc.), reaction solvents when used, and in some cases Includes stable materials (eg, impurities such as peroxides other than hydrogen peroxide). Components other than hydrogen peroxide are included in the first component or the second component depending on the type and the separation means.

As the separation means, conventional methods such as distillation, partitioning (extraction), crystallization, filtration, adsorption (ion exchange etc.), absorption, stripping, membrane separation, and a combination of these can be used. In particular, when the separation and purification is performed by distillation by utilizing the difference in boiling point of each component, hydrogen peroxide can be recovered with a simple operation and high yield (first separation step). Therefore, in the separation step, usually, the first component and the second component are separated by distillation (first distillation step).

The first component containing at least hydrogen peroxide is
Often contains residual substrates, by-products (ketones and aldehydes), oxidation catalyst systems, reaction solvents, etc.
It is subjected to the second separation step and is further separated and purified (second
Separation step). In the second separation step, the conventional means exemplified above can be used, but usually, the first component containing hydrogen peroxide and the second component containing less hydrogen peroxide than the first component are obtained by distillation. Separated (second distillation step).

In the first and second separation steps, the separated first and second components may be recycled to the reaction step as they are, or they may be subjected to a regeneration step described below or a conventional separation and purification step before the reaction. It may be recycled to the process. It may also be collected as waste.

[(C) Alcohol Regenerating Step] In the alcohol regenerating step, the by-product aldehyde or ketone produced in the (A) reaction step is regenerated into a substrate alcohol.

As a method for regenerating alcohol, for example, a conventional hydrogenation reaction can be used. For example, the first separated in the separation step and containing a ketone and an aldehyde
Alternatively, the alcohol can be regenerated by contacting the second component with hydrogen in the presence of a catalyst. As a catalyst for such a hydrogenation reaction, for example, a palladium-based catalyst, a Raney nickel-based catalyst or the like can be used, and Raney nickel is usually used.

Part or all of the regenerated alcohol or the mixture containing this alcohol is returned to the reaction step (A) for recycling.

[(D) Catalyst Regeneration Step] In the catalyst regeneration step, the oxidation catalyst system (including the oxidation catalyst and the cocatalyst) whose activity has been lowered (deactivated) in the reaction step (A) is regenerated.

The oxidation catalyst with degenerated or reduced activity is mainly composed of a polyvalent carboxylic acid corresponding to an imide compound or an acid anhydride thereof (for example, phthalic acid imide, phthalic anhydride, etc.). It can be regenerated by treating with hydroxylamine or reacting with hydroxylamine. In addition, the oxidation catalyst whose deterioration or activity is lowered is converted into a polyvalent carboxylic acid or a salt thereof using an acid or an alkali, and if necessary,
After conversion into an acid anhydride, the oxidation catalyst may be regenerated by treating or reacting with hydroxylamine.

As hydroxylamine, free hydroxylamine or a salt of hydroxylamine (sulfate,
Hydrochloride, phosphate, etc.) may also be used. The regeneration reaction may be performed by reactive distillation that is performed while removing the produced ammonia and / or water. As the acid, hydrogen chloride, hydrogen halide such as hydrogen bromide, hydrofluoric acid,
Inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid;
Examples thereof include sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid. The acid is preferably an anhydride.

The alkali or its salt is not particularly limited, but for example, a hydroxide or oxide of an alkali metal (lithium, sodium, potassium, etc.) or an alkaline earth metal (magnesium, calcium), or the above-mentioned alkali metal salt. Alternatively, an inorganic base such as an alkaline earth metal salt can be used. For example, alkali metal hydroxide (eg, sodium hydroxide, potassium hydroxide, etc.), alkali metal carbonate (sodium carbonate, potassium carbonate, etc.),
Alkali metal hydrogen carbonate (eg, sodium hydrogen carbonate, potassium hydrogen carbonate, etc.), alkaline earth metal hydroxide (magnesium hydroxide, calcium hydroxide, etc.), alkaline earth metal carbonate (magnesium carbonate, calcium carbonate, etc.) And so on. Also, as an alkali,
Ammonia or an organic base [amines (for example, aliphatic amines such as dimethylamine, diethylamine, trimethylamine, triethylamine, methylenediamine, ethylenediamine; heterocyclic amines such as pyridine and morpholine)] may be used. Preferred alkalis are alkali metal hydroxides (sodium hydroxide, potassium hydroxide, etc.). These alkalis or salts thereof can be used alone or in combination of two or more.

Regeneration of the catalyst is carried out at a temperature of 0 to 200 ° C (preferably 5 to 150 ° C, more preferably 10 to 100 ° C).
To a degree, it is done by mixing the deactivated catalyst with the hydroxylamine or acid.

For example, when the oxidation catalyst is N-hydroxyphthalimide and it coexists with an aldehyde or a ketone,
In the alcohol regeneration step, N-hydroxyphthalimide may be hydrogenated to form phthalimide. In such a case, a mixed solution containing an aldehyde or a ketone, a regenerated alcohol, an oxidation catalyst (N-hydroxyphthalimide), and a modified oxidation catalyst (phthalimide) is washed with water or an alkaline aqueous solution, and N is added to the water phase side. -By extracting hydroxyphthalimide and phthalimide and treating the extract with hydroxylamine, the oxidation catalyst (N-hydroxyphthalimide) can be regenerated from the modified oxidation catalyst (phthalimide). In this case, since the aldehyde, ketone and regenerated alcohol are hardly dissolved in water, they can be separated as an organic phase and can be returned to the reactor and reused.

A part or all of the oxidation catalyst regenerated in the catalyst regeneration step may be returned to the reaction step (A) and reused.

The catalyst regeneration step is not always required as long as the activity of the oxidation catalyst is maintained, and the oxidation catalyst used in the reaction may be recycled to the reaction step without being subjected to the catalyst regeneration step. (Catalyst separation step) In the alcohol regeneration step, if an oxidation catalyst is mixed in an aldehyde, a ketone, or a mixture thereof with an alcohol, depending on the conditions, the oxidation catalyst is hydrogenated by hydrogenation for alcohol regeneration. It may be done. Therefore, it is preferable that the first or second component containing the by-produced aldehyde or ketone contains substantially no oxidation catalyst. Therefore, the catalyst
It may be previously separated from the reaction mixture and the first or second component (catalyst separation step). The catalyst separation step may be performed after the reaction step and prior to the separation step (B), or after the separation step (B) or after the alcohol regeneration step (C). Especially when the catalyst separation step is performed before the alcohol regeneration step,
By the hydrogenation done for the regeneration of alcohol,
The oxidation catalyst can be efficiently recycled without the imide compound being hydrogenated. The treated product after the catalyst separation step may be returned to the separation step (B) again. Oxidation catalysts (including their derivatives) can be separated by conventional separation means (eg distillation, partitioning (extraction etc.), crystallization, filtration, adsorption (ion exchange etc.),
Absorption, desorption, membrane separation, and a combination of these)
Can be easily separated.

For example, when a catalyst which is substantially insoluble in the reaction mixture is used, the reaction mixture can be directly filtered with a filter to separate the catalyst. When a catalyst that dissolves in the reaction mixture is used, the reaction mixture is cooled to precipitate the catalyst, or the catalyst is extracted and separated with a solvent that is incompatible with the reaction mixture and dissolves the catalyst, or The catalyst may be deposited by concentrating the volatile components by evaporating the volatile components and then filtering with a filter. The dissolved catalyst component may be returned to the reactor together with the reaction solvent and recycled without being separated. The treatment operation of the catalyst separation step can be carried out continuously, batchwise or semi-batchly.

When a co-catalyst is used, the separated catalyst component may be subjected to incineration treatment to recover the co-catalyst (for example, transition metal such as cobalt) and reuse it.
The metal component of the cocatalyst may be recovered by an ion exchange resin.

The catalyst separation step is not always necessary. For example, in the case of carrying out the reaction by carrying the oxidation catalyst or the cocatalyst in the reaction apparatus in a fixed bed or the like in the reaction step (A), it was obtained. Since there is substantially no oxidation catalyst or co-catalyst in the reaction mixture, the catalyst separation step can be omitted. Also, for example, the catalyst separation step can be omitted when the catalyst component is not separated from the reaction mixture and is returned to the reaction apparatus and reused together with the solvent and the like.

In the present invention, each of the above steps (A)-
In (D), if necessary, a conventional additive such as a stabilizer (for example, a stabilizer of hydrogen peroxide) or a decomposition accelerator [for example, an unfavorable component (for example, a high-boiling point peroxide, etc. Decomposition accelerator etc.])] may be added.

The method of the present invention comprises: (C) an alcohol regeneration step, in addition to (A) the reaction step and (B) the separation step.
(D) Since the catalyst regeneration step is included, the raw materials can be effectively used and hydrogen peroxide can be efficiently produced by a series of processes.

A specific method of the present invention will be described below with reference to the drawings.

FIG. 1 is a flow chart for explaining an example of the manufacturing method of the present invention. In this example, the substrate alcohol is substantially water insoluble and the alcohol has a higher boiling point than water and hydrogen peroxide. Furthermore, the boiling point of the reaction solvent is lower than that of water and hydrogen peroxide. That is, the boiling point of the alcohol is the highest, followed by the aldehyde or ketone,
The boiling point decreases in the order of hydrogen peroxide, water, and reaction solvent. More specifically, in this example, as the alcohol of the substrate, 1-
Phenyl ethanol, acetonitrile as reaction solvent,
N-hydroxyphthalimide (NHP) as an oxidation catalyst
I) is used.

In the process of this example, the reaction step (A)
And high boiling point components (hydrogen peroxide, oxidation catalyst, by-products, etc.) and low boiling point components (solvents, etc.) by distillation from the reaction mixture
A first distillation step (B1) for separating into a high boiling point component and a second distillation step (B2) for separating a low boiling point component and a high boiling point component containing hydrogen peroxide by distillation from the high boiling point component, and (C2) ) Alcohol regeneration step, (D) catalyst regeneration step,
And a solvent recovery step. Therefore, in the process of this example, the reaction solvent can be recovered at a high recovery rate.

[Reaction Step (A)] 1-phenylethanol as a substrate, acetonitrile as a reaction solvent, and N-hydroxyphthalimide as an oxidation catalyst were charged in the reaction apparatus and air was supplied under the conditions exemplified in the section of the reaction step. An appropriate reaction condition is selected from the above to carry out the oxidation reaction (reaction step 11). By the oxidation reaction in the reaction step 11, hydrogen peroxide is produced and acetophenone is produced as a by-product. Therefore, the reaction mixture solution obtained from the reaction step 1 contains hydrogen peroxide, acetophenone, 1-phenylethanol, acetonitrile and N-
Includes hydroxyphthalimide. The reaction mixture is subsequently subjected to the first distillation step 12.

[First Distillation Step (B1)] In the first distillation step 12, the reaction mixture is separated into a top liquid (low boiling point component) and a bottom liquid (high boiling component). In the example of FIG. 1, the low boiling point component may include the solvent acetonitrile and a trace amount of water generated by decomposition of hydrogen peroxide by azeotropic distillation with acetonitrile. The high boiling point components include hydrogen peroxide, unreacted substrate, by-product (acetophenone), oxidation catalyst and the like. The amounts of 1-phenylethanol and acetophenone that are azeotropic with water are
It is a negligible amount compared to water and acetonitrile.

Distillation is usually carried out using a distillation column, and the number of stages of the distillation column is, for example, 1 to 100, preferably 5
80 steps, more preferably 10-70 steps, especially 10-6 steps
It may be about 0 steps. The distillation operation depends on the type of low-boiling point component (for example, low-boiling point solvent) and the column top temperature-2
0 ° C to 140 ° C (preferably 0 to 120 ° C, more preferably 20 to 100 ° C, especially 40 to 100 ° C), tower bottom temperature 20 to 160 ° C, preferably 30 to 140 ° C, more preferably 50 to 120 ° C. ℃, pressure 0.13kPa
˜2 MPa, preferably about 1.3 kPa to 1 MPa. In particular, it is preferably carried out under reduced pressure (for example, 1 to 100 kPa, preferably 2 to 80 kPa, more preferably about 3 to 50 kPa) or normal pressure. In addition, a suitable reflux ratio (for example, 0.01 to 50, preferably 0.1 to 4)
0, and more preferably about 1 to 30) while refluxing the distillate.

It is also possible to use an evaporator, and the evaporation operation is carried out, for example, at a pressure of 0.13 kPa to 2 MPa, preferably 1.3 kPa to 1 MPa, -20 ° C to 160 ° C, preferably 0 to 140 ° C. More preferably, it can be carried out in a temperature range of about 20 to 120 ° C, particularly about 40 to 100 ° C.

(Reaction Solvent Recovery Step) In the reaction solvent recovery step, the low boiling point component from the first distillation step 12 is recovered and recycled to the reaction step 11. As a method for separating and recovering the reaction solvent, conventional methods such as concentration (condensation), distillation, extraction, absorption, stripping, adsorption, ion exchange and membrane separation can be used.

In this example, the low boiling point component is supplied to the condenser or absorption tower, and the solvent acetonitrile is recovered and returned to the reaction step 1 for reuse (reaction solvent recovery step 1
6). In this example, the low boiling point component containing acetonitrile is reused in the reaction step, but the low boiling point component is used as the absorption liquid of the absorption tower for cleaning the off gas of the reaction device and the distillation tower. Good.

[Second Distillation Step (B2)] In the second distillation step 13, the high boiling point component from the first distillation step 12 is
The top liquid (low boiling point component) and the bottom liquid (high boiling point component) are separated. In the example of FIG. 1, the low boiling point component after the second distillation step contains hydrogen peroxide, and the high boiling point component contains unreacted substrate, by-product and oxidation catalyst. This low boiling point component is recovered from the top of the column as an aqueous hydrogen peroxide solution. In the example of FIG. 1, since the high-boiling point component is a homogeneous system (homogeneous solution), the high-boiling point component can be directly subjected to the alcohol regeneration step, and the manufacturing apparatus can be simplified, which is advantageous in cost. .

The distillation can be carried out under the same conditions as exemplified in the section of the first distillation step. By adjusting the amount of water charged to the distillation column and the distillation conditions, the concentration of hydrogen peroxide in the hydrogen peroxide aqueous solution to be recovered (for example, 10
To 90% by weight, preferably 20 to 80% by weight, more preferably about 30 to 70% by weight). Also,
If necessary, a stabilizer (for example, a stabilizer for hydrogen peroxide) may be mixed with the reflux liquid and charged from the top of the distillation column.

[Alcohol regeneration step (C)] Distillation step 3
Is a uniform solution containing N-hydroxyphthalimide, 1-phenylethanol and acetophenone. In the alcohol regeneration step (C), the column bottom liquid is subjected to an alcohol regeneration step 14, and acetophenone is regenerated to 1-phenylethanol by hydrogenation. The regenerated 1-phenylethanol is reused in the reaction step 11. Regeneration of alcohol is performed by a method similar to the operation exemplified in the above-mentioned regeneration section.

In the example of FIG. 1, since the oxidation catalyst N-hydroxyphthalimide contained in the bottom liquid of the column is hardly deactivated, it is not necessary to provide the catalyst regeneration step before the alcohol regeneration step. However, when N-hydroxyphthalimide coexists with acetophenone as a by-product, N-hydroxyphthalimide may be hydrogenated and deteriorated to form phthalimide. Therefore, the oxidation catalyst hydrogenated through the alcohol regeneration step is subjected to the catalyst regeneration step to be regenerated.

[Catalyst Regeneration Step (D)] In the catalyst regeneration step, the oxidation catalyst is regenerated. In this example, N-hydroxyphthalimide and phthalimide are separated from the treated product after the alcohol regeneration treatment with water or an alkaline aqueous solution, and the separated oxidation catalyst is subjected to the catalyst production regeneration step 15 to regenerate the N-hydroxyphthalimide. It can be reused by returning to the reaction step again. The separation of the oxidation catalyst is
It can be carried out by the conventional separating means exemplified above. In this example, the oxidation catalyst is separated by extraction.

(Extraction step) The extraction is carried out by a conventional method, for example, extraction temperature -20 ° C to 150 ° C, preferably 0 to 130 ° C (eg 0 to 100 ° C), more preferably 5 to 50 ° C. Pressure range of 0.13kPa to 2M
Pa, preferably about 1.3 kPa to 1 MPa.
In addition, in order to enhance the liquid separation property or the extractability, a common extraction solvent, for example, an aqueous solvent (for example, an aqueous alkaline solution), a hydrophobic solvent (hydrocarbons, esters, ethers, ketones, nitriles, etc.) ) May be used.

The separated oxidation catalyst is regenerated by the method described in the above-mentioned catalyst regeneration step. The regenerated oxidation catalyst is supplied to the reaction step 11 again and reused.

If the activity of the catalyst used in the reaction is not lowered, the catalyst regeneration step and extraction step are unnecessary.

In reaction step 1, a cocatalyst may be used together with N-hydroxyphthalimide which is an oxidation catalyst. In this case, the metal component of the cocatalyst is contained in the bottom liquid of the first distillation step 12 and the bottom liquid of the second distillation step 13, and is supplied to the catalyst regeneration step 15 together with the oxidation catalyst in the reaction step 11 To be recycled. In particular, when hydrogenated N-hydroxyphthalimide is separated in the alcohol regeneration step, the metal component of the cocatalyst is extracted to the aqueous phase side together with N-hydroxyphthalimide by the above-mentioned extraction with water or an aqueous alkaline solution.

Instead of 1-phenylethanol, 2-octanol or benzhydrol, which has a high boiling point like 1-phenylethanol, can be used as a substrate. In this case, since the solubility of N-hydroxyphthalimide in 2-octanol, 2-octanone produced as a by-product thereof, or benzhydrol and benzophenone produced as a by-product thereof is small, the second distillation step 3
The bottom liquid of the above becomes a slurry liquid.

Further, instead of 1-phenylethanol, cyclohexanol having a high boiling point like 1-phenylethanol can be used as a substrate. In this case, since the solubility of N-hydroxyphthalimide in cyclohexanol and cyclohexanone produced as a by-product thereof is sufficient, the bottom liquid in the second distillation step 13 becomes a uniform liquid.

Further, as the reaction solvent, a reaction solvent having a boiling point higher than that of water, hydrogen peroxide or alcohol may be used.

FIG. 2 is a flow chart showing another method of the present invention. In this example, a solvent having a boiling point higher than that of water, alcohol and hydrogen peroxide is used as the reaction solvent. That is, in this example, the reaction solvent has the highest boiling point,
Subsequently, the boiling point decreases in the order of alcohol, aldehyde or ketone, hydrogen peroxide, and water. In this example, in FIG.
In place of 1-phenylethanol used in the above example, cyclohexanol is used as a substrate which is hardly dissolved in water and has a higher boiling point than water and hydrogen peroxide. Further, benzonitrile as a reaction solvent and N as an oxidation catalyst
-Hydroxyphthalimide (NHPI) is used.

In the example of FIG. 2, after the second distillation step, the high boiling point component is subjected to a liquid separation step 27 and a third distillation step 28 to separate by-products, and the separated by-products are regenerated with alcohol. It is basically the same as the process of FIG. 1 except that it is subjected to step 24. In the example of FIG. 2, the reaction mixture of the reaction step 21 is subjected to the first distillation step 22 and the low boiling point component containing hydrogen peroxide is subjected to the second distillation step 23 to remove hydrogen peroxide from the bottom liquid. obtain. Further, after the low boiling point component obtained from the second distillation step 23 is subjected to the liquid separation step 27, the by-products are separated from the organic phase by distillation (third distillation step 28) and then subjected to the alcohol regeneration step 24. , Recycle to the reaction process.

In this example, the low boiling point component containing hydrogen peroxide and the high boiling point component containing the reaction solvent and the oxidation catalyst can be separated with high purity and high recovery rate by distillation. Can be recycled directly to the reaction process. Further, due to the difference in the boiling points of the respective components, it is possible to prevent the by-product from migrating to the low-boiling point component and the oxidization catalyst from migrating to the low-boiling point component, so that the oxidation catalyst can be prevented from being reduced in the alcohol regeneration step.

[Reaction Step (A)] The reaction step 21 is carried out by the same method as the method exemplified in the reaction step of FIG. Therefore, in the reaction mixture obtained by the oxidation reaction,
Hydrogen peroxide, cyclohexanone, cyclohexanol,
Benzonitrile and N-hydroxyphthalimide are included. The reaction may be carried out while refluxing the volatile component.

[First Distillation Step (B1)] In the first distillation step 22, the reaction mixture is distilled to form hydrogen peroxide,
It is separated into a low boiling point component containing unreacted substrate, by-products, water produced by the reaction and the like, and a high boiling point component containing benzonitrile, an oxidation catalyst and the like. In this example, the high boiling point component is a homogeneous solution. Distillation is performed in the same manner as the distillation operation illustrated in the distillation step of FIG. The separated low boiling point component is further supplied to the second distillation step 23. Further, in this example, no solid substance is deposited in the above reaction, and the high-boiling point component is a uniform solution, so that the high boiling point component is directly supplied to the catalyst regeneration step 25.

[Catalyst Regeneration Step (D)] The high boiling point component obtained in the first distillation step is regenerated if necessary, and then the reaction step 2
Recycle to 1. The catalyst regeneration step 25 is performed by a method similar to the method exemplified above.

[Second Distillation Step (B2)] In the second distillation step 23, from the low boiling point component obtained in the first distillation step, as the low boiling point component, cyclohexanol which is an unreacted substrate and a by-product are formed. Cyclohexanone and azeotropic water are separated, and an aqueous hydrogen peroxide solution is separated as a high boiling point component. Distillation is performed in the same manner as the distillation operation exemplified in the section of FIG.
The low boiling point component is further supplied to the liquid separation step 27.

[Liquid Separation Step] In the liquid separation step 27, the low boiling point component obtained from the second distillation step is separated into an aqueous phase and an organic phase by liquid separation. In this example, the organic phase contains cyclohexanol and cyclohexanone. The aqueous phase may contain residual hydrogen peroxide. The liquid separation operation can be appropriately selected from the same conditions as the extraction operation exemplified above. The separated aqueous phase is recycled as it is to the second distillation step as reflux water, and the organic phase is supplied to the third distillation step 28 to remove azeotropic water.

[Third distillation step (B3)] In the third distillation step 28, cyclohexanol and cyclohexanone are dehydrated. The organic phase from the liquid separation step 27 is separated into a low boiling point component (water) and a high boiling point component (cyclohexanone and cyclohexanol). Distillation is performed in the same manner as the distillation operation exemplified in the section of FIG. The low boiling point component is returned to the liquid separation step 27 as it is, and the high boiling point component is supplied to the alcohol regeneration step 24.

[Alcohol Regeneration Step (C)] In the alcohol regeneration step 24, the high boiling point component separated in the third distillation step 28 is regenerated into alcohol and then recycled to the reaction step 21. If necessary, cyclohexanol and cyclohexanone may be separated by distillation, and after the separation, only cyclohexanone may be supplied to the alcohol regeneration step 24 to regenerate cyclohexanol. Regeneration of alcohol is performed by the method exemplified above.

In the reaction step 21, a cocatalyst may be used together with N-hydroxyphthalimide which is an oxidation catalyst. In this case, the metal component of the co-catalyst is contained in the bottom liquid of the first distillation step 22 and is used in the catalyst regeneration step.
The regenerated or recovered metal component is returned to the reaction step 21 for reuse.

Incidentally, the activities of the oxidation catalyst and the cocatalyst are usually maintained even after the reaction step 21, and therefore the catalyst regeneration step 25 is often unnecessary.

In the example of FIG. 2, 2-octanol having a boiling point between hydrogen peroxide and the reaction solvent may be used as a substrate instead of cyclohexanol, like cyclohexanol. When the boiling point of 2-octanol or 2-octanone produced as a by-product is close to that of the reaction solvent, water can be charged into the distillation column in the first distillation step, and the aqueous hydrogen peroxide solution can be recovered from the top of the distillation column. In this case, the bottom liquid obtained in the first distillation step contains 2-octanol, 2-octanone by-produced, benzonitrile and N-hydroxyphthalimide, and is supplied to the alcohol regeneration step and the catalyst production regeneration step. If necessary, a substance produced by hydrogen reduction of N-hydroxyphthalimide or benzonitrile may be separated and produced by a conventional method.

FIG. 3 is a flow chart showing still another example of the present invention. In this example, a system similar to the example of FIG. 1 is used except that benzonitrile is used as the substrate. That is, in this example, alcohol has the highest boiling point, followed by aldehyde or ketone, reaction solvent, hydrogen peroxide,
The boiling point decreases in the order of water. In this case, specifically, benzhydrol is used as the alcohol of the substrate, benzonitrile is used as the reaction solvent, and N-hydroxyphthalimide (NHPI) is used as the oxidation catalyst.

The method of FIG. 3 is basically the same as the process of FIG. 1 except that the high boiling point component obtained from the first distillation step is subjected to the alcohol regeneration step and the catalyst regeneration step. In the example of FIG. 3, the reaction mixture from the reaction step 31 is subjected to the first distillation step 32, and a low boiling point component containing benzonitrile and hydrogen peroxide and a high boiling point component containing benzonitrile, a by-product and an oxidation catalyst. The low boiling point component into the second
And the high boiling point component are subjected to the alcohol regeneration step 34 and the catalyst regeneration step 35. In the second distillation step 33, the hydrogen peroxide aqueous solution (low boiling point component) and benzonitrile (high boiling point component) are separated from the low boiling point component obtained from the first distillation step 32 and recycled to the reaction step. .

[Reaction Step (A)] The reaction is carried out in the same manner as in FIG. The oxidation reaction in the reaction step 31 produces hydrogen peroxide and benzophenone as a by-product of benzhydrol. Therefore,
The reaction mixture obtained from the reaction step 31 is hydrogen peroxide,
Includes benzophenone, benzhydrol, benzonitrile and N-hydroxyphthalimide. The reaction mixture obtained from the reaction step 31 is subsequently subjected to the first distillation step.

[First and Second Distillation Steps (B) and Alcohol and Catalyst Regeneration Steps (C) and (D)] In the first distillation step, the reaction mixture is heated to a low boiling point containing benzonitrile and hydrogen peroxide. The components are separated into high-boiling components including benzonitrile, by-products and oxidation catalyst. The separated low boiling point component is further subjected to the second distillation step to be separated into a low boiling point component containing an aqueous hydrogen peroxide solution and a high boiling point component containing benzonitrile. High boiling point component is reaction step 31
May be recycled to. The high boiling point component from the first distillation step is supplied to the alcohol regeneration step and, if necessary, the catalyst regeneration step and recycled.

The distillation operation and the alcohol and catalyst regeneration operation are carried out by the same method as exemplified in the section of FIG. In the first and second distillation steps, the same apparatus is used and a low boiling point component containing hydrogen peroxide, benzonitrile,
It may be separated into a high boiling point component including a by-product and an oxidation catalyst. When the first and second distillation steps are performed at once in this way, the manufacturing equipment can be simplified, which is advantageous in terms of cost.

As in the method of FIG. 1, reaction step 31
In, a cocatalyst may be used together with N-hydroxyphthalimide which is an oxidation catalyst.

FIG. 4 is a flow chart showing another method of the present invention. In this example, a system similar to the process of FIG. 1 was used, except that no reaction solvent was used, the alcohol used as the substrate was almost insoluble in water, and the boiling point was lower than that of water and hydrogen peroxide. is doing. That is, in the example of FIG. 4, hydrogen peroxide has the highest boiling point, and subsequently,
The boiling point decreases in the order of water, alcohol, aldehyde or ketone. Specifically, isopropanol is used as the substrate alcohol and N-hydroxyphthalimide (NHPI) is used as the oxidation catalyst.

In the process of FIG. 4, prior to the second distillation step, the high boiling point component from the first distillation step is supplied to the solid-liquid separation step 50, and the low boiling point component from the first distillation step is added to the first distillation step. 3 is basically the same as the process of FIG. 1 except that it is subjected to the distillation step 48 of 3. In the process of Figure 4,
Since no solvent is used, the manufacturing equipment can be simplified.

[Reaction Step (A)] The reaction is carried out in the same manner as in FIG. Due to the oxidation reaction in the reaction step 41, hydrogen peroxide is generated and acetone is also generated as a by-product of isopropanol. Thus, the reaction mixture from reaction step 41 comprises hydrogen peroxide, acetone, isopropanol and N-hydroxyphthalimide.
The reaction mixture is subsequently subjected to the first distillation step.

[First Distillation Step (B1)] In the first distillation step 42, a low boiling point component containing water generated by the reaction with the by-product from the reaction mixture by distillation, hydrogen peroxide, an oxidation catalyst and It is separated into high-boiling components including water generated by the reaction. The distillation is performed under the same conditions as those exemplified in the section of FIG. The high boiling point component is supplied to the solid-liquid separation step 50 to remove the precipitated solid. The low boiling point component is supplied to the third distillation step 48.

[Solid-liquid separation step and catalyst regeneration step (D)]
The high boiling components obtained from the first distillation step 42 include hydrogen peroxide, water and N-hydroxyphthalimide. In this high boiling point component, N-hydroxyphthalimide is precipitated as a solid, so that N-hydroxyphthalimide can be separated by solid-liquid separation. Solid-liquid separation is performed by a conventional method (especially filtration).

The filtration temperature is an appropriate temperature, for example, -20.
C. to 100.degree. C., preferably 0 to 80.degree. C., more preferably about 20 to 60.degree. Filtration pressure is 0.13 kPa to 2 MPa, preferably 1.3 kPa to 1 MPa
You can choose from a range of degrees.

If necessary, it may be washed. The washing solvent can be selected according to the type of catalyst (N-hydroxyphthalimide), and for example, water or the like can be used. The washing operation is carried out at an appropriate temperature [-20 to 80 ° C, preferably 0
-60 ° C, more preferably 10-40 ° C range]
Done in.

The separated catalyst is supplied to the catalyst regeneration step 45 to be regenerated, and then recycled to the reaction step. Regeneration of the catalyst is performed by the method exemplified above.

[Second Distillation Step (B2)] The aqueous solution of hydrogen peroxide separated in the solid-liquid separation step 50 is continuously subjected to the second distillation step (B2).
And is separated into a low boiling point component containing water and a high boiling point component containing hydrogen peroxide. In addition, distillation is
This is performed by the method illustrated in FIG.

[Third distillation step (B3) and alcohol regeneration step (C)] The low boiling point components from the first distillation step 42 include isopropanol, acetone and a trace amount of water.
This low boiling point component is subjected to the third distillation step 48, and is separated into a low boiling point component containing acetone and a high boiling point component containing isopropanol and water. The low boiling point component is subsequently provided to the alcohol regeneration step 44, and the high boiling point component and the regenerated alcohol are recycled to the reaction step 41. In addition,
Distillation and alcohol regeneration operations are performed in the same manner as described above.

In the reaction step 41, a cocatalyst may be used together with N-hydroxyphthalimide which is an oxidation catalyst.

In the process shown in FIG. 4, it is possible to use a reaction solvent having a high boiling point such as benzonitrile as the reaction solvent. In this case, the reaction solvent and N-hydroxyphthalimide can be recovered from the bottom of the column by concentrating the reaction mixture before subjecting it to the first distillation step 42, and the recovered solvent and catalyst reaction step 41 can be recovered. It can be returned to and reused. Therefore, in this case, the solid-liquid separation step 33 and the catalyst production / regeneration step 34 are unnecessary. The low boiling point component obtained from the concentration step,
It contains isopropanol, acetone, and hydrogen peroxide, and is subsequently supplied to the first distillation step 42 and subjected to the same treatment as described above. In this case, the first distillation step 4
By supplying water to 2, an aqueous hydrogen peroxide solution can be obtained from the bottom of the tower.

The method of the present invention comprises the reaction step (A)
A separation step (B), a (C) alcohol regeneration step,
If necessary, the (D) regeneration step may be provided, and the order of each step is not particularly limited. For the separation of each component (hydrogen peroxide, substrate, by-product, oxidation catalyst, co-catalyst, solvent, etc.), distillation (evaporation, etc.),
It can be carried out by partitioning (extraction etc.), crystallization (washing etc.), filtration, adsorption (ion exchange etc.), absorption, diffusion, membrane separation, filtration, drying and a combination thereof. The separated components may be further purified if necessary (purification step) or may be recycled as they are.

Further, in the method of the present invention, in addition to the steps (A) to (D), for example, the above-mentioned catalyst production step,
A catalyst solution preparation step, a hydroxylamine production step, a catalyst separation step, a solvent recovery step, etc. may be included.

For example, from the reaction mixture of the reaction step (A), solid components (such as an oxidation catalyst) that have been deposited in advance may be separated by a separation operation such as filtration, and then the components containing hydrogen peroxide may be separated by distillation. .

Further, a conversion treatment step of converting an unstable by-product (eg, peroxide other than hydrogen peroxide) generated in each step into a stable substance by a method such as heat treatment may be included. .

In particular, the method of the present invention preferably comprises a separation step of separating the component containing hydrogen peroxide and the component containing the catalyst and / or by-product by a distillation operation. By utilizing the distillation operation, hydrogen peroxide can be efficiently separated from other components (oxidation catalyst etc.).

In the present invention, the substrate, the oxidation catalyst (including the co-catalyst), the solvent, the effective components in the by-products (aldehydes and ketones corresponding to the substrate), the reaction solvent and the like need not necessarily be recycled. In order to industrially advantageously obtain hydrogen peroxide efficiently, it is advantageous to recycle the components to a reaction device or a separation device and reuse them. The separated catalyst may be recycled to the reaction system without purification, or may be recycled to the reaction system after subjecting the deactivated catalyst to the catalyst regeneration step.

As the separating device, a conventional device can be used, and one or a plurality of devices may be used. When using multiple devices, the devices may be connected in series and / or in parallel. The shape of the device may be spherical, cylindrical or the like.
In particular, a special device is not required inside the separation device, but a device such as a perforated plate for dividing the inside into multiple chambers may be provided. Further, in order to enhance stirring efficiency, a mechanical stirring device such as a stirring blade may be provided. The distillation may be performed while removing water in combination with a water separator such as a decanter.

Further, as the distillation column and the extractive distillation column,
Tana plate tower, perforated plate tower, packed tower (regular packed tower, irregular packed tower), bubble bell tower, valve tower and the like can be used. As the extraction device, a conventional device such as a mixer settler, a perforated plate tower, a spray tower, a packed tower, a rotary disk extraction tower (RD
C), a curl column, a centrifugal extractor, a ring & plate, etc. can be exemplified. As the filtration device, various devices such as centrifugal sedimentation, centrifugal filtration, a filter press, a nutsche, and a filter dryer can be used. Particularly preferable filtration devices include centrifugal sedimentation, centrifugal filtration, filter press and the like. As the concentrating device, various devices, for example, natural circulation type, horizontal tube type evaporator, natural circulation type vertical short tube type evaporator, horizontal tube descending film evaporator, vertical long tube descending film evaporator, forced circulation Type horizontal tube type evaporator, forced circulation type vertical tube type evaporator, stirred film type evaporator, FFE (Fallin
g Film Evaporator), WFE (Wiped Film Evaporato)
r) etc. can be illustrated. Examples of the dryer include a conical dryer, a Nauta mixer, a filter dryer and the like. These devices may be used alone or in combination of two or more.

[0177]

According to the present invention, since hydrogen peroxide is produced by oxidizing a primary alcohol or a secondary alcohol using a specific imide compound as a catalyst, hydrogen peroxide can be produced under milder conditions. Can be efficiently produced, and hydrogen peroxide can be easily recovered in a high yield by a series of processes.

[0178]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples.

Example 1 1 L of a titanium stirring and mixing reactor was used, and 1-
Phenylethanol (MBA) 13.3% by weight, N-hydroxyphthalimide (NHPI) 1.8% by weight as an oxidation catalyst, and acetonitrile 8 as a reaction solvent.
A mixed solution containing 4.9% by weight was charged at 4 kg / H, and air was charged at 190 NL / H at a reaction temperature of 75 ° C.
The oxidation reaction was performed at a pressure of 6 atm (0.6 MPa). As a result of analyzing the product in the reaction mixed solution by gas chromatography, the conversion rate of 1-phenylethanol was 38% and the selectivity of hydrogen peroxide was 97%.

Next, from the reaction mixture solution obtained above,
Acetonitrile was separated by vacuum distillation using a distillation column (number of stages: 20 stages). The distillation conditions are a column top pressure of 80 mmH.
g, reflux ratio 0.25, tower top temperature 22 ° C., tower bottom temperature 115
It was ℃. The recovery rate of acetonitrile is 99.9% or more, and hydrogen peroxide, water, 1-
Phenylethanol and acetophenone are 300 ppm or less, 150 ppm or less, and 15 ppm by weight, respectively.
The content was 0 ppm or less and 150 ppm or less. The recovered acetonitrile could be recycled to the reactor.

Subsequently, the bottoms of the above first distillation column was charged into a second distillation column (the number of stages: 40), and hydrogen peroxide was separated and recovered by vacuum distillation. Distillation conditions are column top pressure 4
The temperature was 0 mmHg, the reflux ratio was 1.5, the tower top temperature was 53 ° C, and the tower bottom temperature was 115 ° C. Water was charged in the second distillation column to distill a 70% by weight hydrogen peroxide aqueous solution. In this case, the recovery rate of hydrogen peroxide was 99% or more, and 1-phenylethanol and acetophenone detected in the recovered hydrogen peroxide aqueous solution were 100 ppm or less (weight basis). In addition, as canned liquid, NHP
A mixed solution of I, 1-phenylethanol and acetophenone was obtained. This mixed solution is a homogeneous solution,
Acetophenone can be easily reduced to 1-phenylethanol by hydrogen reduction treatment. The NHPI and 1-phenylethanol thus obtained were returned to the reactor and reused.

Example 2 A 1 L titanium-stirring-mixing reactor was used in which 6.1% by weight of cyclohexanol (ANOL) was used as a substrate and 1.25% of N-hydroxyphthalimide (NHIP) was used as an oxidation catalyst.
0% by weight and 92.9 of benzonitrile as a reaction solvent.
% Mixed solution at 4 kg / H, air 43NL
/ H, reaction temperature 75 ° C, pressure 6 atm (0.6M
The oxidation reaction was performed in Pa). As a result of analyzing the product in the reaction mixture by gas chromatography, the conversion of cyclohexanol was 17% and the selectivity of hydrogen peroxide was 8%.
It was 4%.

Next, from the reaction mixture solution obtained above,
A solution containing benzonitrile and N-hydroxyphthalimide was separated and recovered as a bottom liquid by vacuum distillation using a distillation column (the number of plates: 50). The distillation conditions were a column top pressure of 30 mmHg, a reflux ratio of 30, a column top temperature of 62 ° C. and a column bottom temperature of 92 ° C., and a solution containing benzonitrile and N-hydroxyphthalimide was separated at a recovery rate of 99.9% or more. Cyclohexanol detected from the separated solution was 600 ppm or less (weight basis), and hydrogen peroxide was not detected. The recovered solution was a uniform mixed solution, and was recycled to the reactor to reuse benzonitrile and N-hydroxyphthalimide.

Subsequently, the distillate of the first distillation column was charged into the second distillation column (the number of stages: 40) and vacuum distillation was carried out. The distillation conditions are a column top pressure of 500 mmHg, a reflux ratio of 5, a column top temperature of 85 ° C. and a column bottom temperature of 100 ° C., and water is charged in the second distillation column to azeotropically distill cyclohexanol and cyclohexanone with water. Along with this, an aqueous solution of hydrogen peroxide having a concentration of 44% by weight was discharged. In this case, the recovery rate of hydrogen peroxide was 99% or more. Although the concentration of the obtained hydrogen peroxide aqueous solution was 44% by weight, it was possible to obtain a 70% by weight aqueous hydrogen peroxide solution by adjusting the amount of water charged and the distillation conditions. . On the other hand, the distilled cyclohexanol and cyclohexanone were dehydrated and separated in another distillation column, and the obtained cyclohexanol was returned to the reactor for reuse. Further, cyclohexanone can be easily reduced to cyclohexanol by hydrogen reduction treatment, and the obtained cyclohexanol was returned to the reactor and reused.

Example 3 In a 1 L stirring and mixing reactor made of titanium, 10.6% by weight of benzhydrol (BH) as a substrate, 0.9% by weight of N-hydroxyphthalimide as an oxidation catalyst, and benzo as a reaction solvent. A mixed solution containing 88.5% by weight of nitrile was charged at 4 kg / H, air was charged at 178 NL / H, and an oxidation reaction was performed at a reaction temperature of 75 ° C. and a pressure of 6 atm.
As a result of analyzing the product in the reaction mixture by gas chromatography, the conversion of benzhydrol was 77% and the selectivity of hydrogen peroxide was 84%.

Next, from the reaction mixture solution obtained above,
A solution containing benzonitrile, benzhydrol, benzophenone and N-hydroxyphthalimide was separated and recovered as a bottom liquid by vacuum distillation in the first distillation column (number of stages: 20). The distillation conditions are column top pressure 70 mmH.
g, the reflux ratio was 5, the tower top temperature was 99 ° C, and the tower bottom temperature was 115 ° C. The recovery rate of the separated and recovered solution is 99.9% or more, and the detected hydrogen peroxide is 200 ppm (weight basis).
Met. The separated and recovered solution is a slurry solution,
It is easily possible to reduce benzophenone to benzohydrol through a hydrogen reduction step and then return it to the reactor to reuse benzonitrile, benzohydrol and N-hydroxyphthalimide.

Subsequently, the distillate of the first distillation column was charged into the second distillation column (the number of stages: 40), and benzonitrile and hydrogen peroxide which were partially separated due to insufficient separation in the first distillation column and hydrogen peroxide were mixed. Separated from aqueous solution. The distillation conditions were a column top pressure of 80 mmHg, a reflux ratio of 5, a column top temperature of 49 ° C. and a column bottom temperature of 116 ° C. Water was charged in the second distillation column to distill a 13 wt% concentration hydrogen peroxide aqueous solution. The recovery rate was 98% or more. The benzonitrile discharged here can be easily returned to the reactor and reused.

[Brief description of drawings]

FIG. 1 is a flow diagram for explaining the method of the present invention.

FIG. 2 is a flow chart for explaining another method of the present invention.

FIG. 3 is a flow chart for explaining still another method of the present invention.

FIG. 4 is a flow chart for explaining another method of the present invention.

[Explanation of symbols]

11, 21, 31, 41 ... Reaction process 12, 22, 32, 42 ... First distillation step 13, 23, 33, 43 ... Second distillation step 14, 24, 34, 44 ... Alcohol regeneration process 15, 25, 35, 45 ... Catalyst regeneration process

Claims (8)

[Claims] 1. The following formula (I): (In the formula, X represents an oxygen atom or an —OR group (in the formula, R represents a hydrogen atom or a protecting group for a hydroxyl group)), and an oxidation catalyst having an imide skeleton is used as a substrate. A method for producing hydrogen peroxide by reacting a primary or secondary alcohol with oxygen, comprising: (A) a reaction step of contacting the substrate with oxygen in the presence of the oxidation catalyst; ) A first component containing at least hydrogen peroxide and a second component having a hydrogen peroxide content lower than that of the first component are separated from the reaction mixture obtained in the reaction step (A). A separation step, and (C) a step of regenerating a primary or secondary alcohol from the first or second component containing by-produced ketone and aldehyde, and recycling to the reaction step (A), D) In the reaction mixture or the first or second component Rare and reactive separation and / or regenerated by requiring oxidation catalyst used in the method for producing hydrogen peroxide comprising the step of recycling to the reaction step (A). 2. The production method according to claim 1, wherein the reaction is carried out in the presence of a reaction solvent, and the first component containing hydrogen peroxide and the second component containing the reaction solvent and the oxidation catalyst are separated by distillation. . 3. The production method according to claim 1, wherein the reaction is carried out in a homogeneous system while suppressing the precipitation of solid matter, and the first component and the second component are separated in the separation step. 4. The production method according to claim 2, wherein a primary or secondary alcohol, a by-produced ketone and aldehyde, and a reaction solvent having a boiling point higher than that of hydrogen peroxide are used. 5. The production method according to claim 1, wherein the alcohol is regenerated by subjecting the first or second component containing no ketone and aldehyde produced as a by-product to the reduction reaction without containing an oxidation catalyst. 6. The substrate is a secondary alcohol as claimed in claim 1.
The method for producing hydrogen peroxide described above. 7. The method for producing hydrogen peroxide according to claim 6, wherein the secondary alcohol is cycloalkanol or aryl alcohol. 8. The oxidation catalyst is represented by the following formula (II): (In the formula, R ¹ and R ² are the same or different and are a hydrogen atom,
Represents a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or an acyl group, and R ¹ and R ² are bonded to each other to form a double bond or an aromatic group. Alternatively, a non-aromatic ring may be formed, and the aromatic or non-aromatic ring formed by R ¹ and R ² is represented by the above formula (I).
It may have at least one imide skeleton represented by. The method for producing hydrogen peroxide according to claim 1, wherein X is represented by the same as above.