JP4908189B2 - Method for producing α, β-unsaturated carboxylic acid, etc. using palladium supported catalyst - Google Patents

Description

  The present invention relates to a palladium-supported catalyst used in a liquid phase oxidation reaction of an olefin or an α, β-unsaturated aldehyde, and to a method for producing the catalyst. Furthermore, the present invention relates to a method for producing a corresponding product by liquid phase oxidation of an olefin or an α, β-unsaturated aldehyde using the catalyst.

  For a catalyst for producing α, β-unsaturated aldehyde or α, β-unsaturated carboxylic acid by liquid phase oxidation of olefin with molecular oxygen, for example, in Patent Document 1, palladium metal or palladium is used. A palladium-supported catalyst in which an intermetallic compound such as lead, bismuth, thallium or mercury is supported on a support such as alumina has been proposed.

Patent Document 1 is characterized in that an olefin is oxidized in the presence of an aqueous solution of at least one molybdenum compound selected from the group consisting of molybdenum oxides and heteropolymolybdates and the above catalyst.
JP 56-59722 A

  However, when a molybdenum compound is used as an aqueous solution, there is a concern about the effects of contamination of the molybdenum compound into the product, the resulting coloration of the product, scale adhesion inside the reactor or inside the piping, and the separation and purification process becomes complicated. It can be easily estimated that the operation becomes difficult due to the fact that the pipe is blocked or the pipe is blocked.

  In Patent Document 1, it is necessary that a water-soluble molybdenum compound and an intermetallic compound of palladium metal or palladium and lead, bismuth, thallium, mercury, or the like coexist, and in particular, palladium, lead, bismuth, and thallium. Alternatively, good results can be obtained when an intermetallic compound such as mercury is used. That is, in Patent Document 1, the presence of the water-soluble molybdenum compound brings out the performance of the palladium-supported catalyst for the first time, and the process problems are not solved. From these viewpoints, development of a catalyst that is easy to handle in process and has high performance is highly desired.

  In addition, the palladium-supported catalyst described in Patent Document 1 is not yet sufficiently active, and in particular, the selectivity for an α, β-unsaturated carboxylic acid and an acid anhydride having an α, β-unsaturated carboxylic acid skeleton is It was not enough. Among them, an acid anhydride having an α, β-unsaturated carboxylic acid skeleton is hydrolyzed by water contained in the solvent or water generated by the reaction, and thus it is extremely difficult to increase the selectivity. On the other hand, an acid anhydride having an α, β-unsaturated carboxylic acid skeleton reacts with an alcohol in the presence of an acid catalyst to give an α, β-unsaturated carboxylic acid ester. The equilibrium constant at this time is larger than that in the case of producing an α, β-unsaturated carboxylic acid ester from an α, β-unsaturated carboxylic acid, and has an advantage of high reactivity. That is, it is desired to develop a catalyst having high activity in a liquid phase oxidation reaction and high selectivity for an acid anhydride having an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton.

  The catalyst used for the liquid phase oxidation reaction of α, β-unsaturated aldehyde preferably has the same performance.

  Accordingly, it is an object of the present invention to be easy to handle in terms of process, enhance the activity of liquid phase oxidation reaction of olefins or α, β-unsaturated aldehydes, α, β-unsaturated carboxylic acids and α, β-unsaturated carboxylic acids. An object of the present invention is to provide a method for producing an acid anhydride having a skeleton with high selectivity, a catalyst therefor, and a method for producing the catalyst.

  The present invention relates to a palladium-supported catalyst used in a liquid phase oxidation reaction of an olefin or an α, β-unsaturated aldehyde, in which palladium is supported on a silica-metal oxide support in which a metal oxide is contained in silica. A palladium-supported catalyst. The metal oxide is, for example, at least one metal oxide selected from the group consisting of tellurium oxide, antimony trioxide, molybdenum trioxide, tin (IV) oxide, titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, and germanium dioxide. The mass of the metal oxide mixed and / or supported on the silica-metal oxide support is, for example, 0.1 to 100 mass percent of the mass of the silica support.

  The present invention provides a method for producing the palladium-supported catalyst, wherein the silica support and the metal oxide are dissolved or dispersed in a solvent and stirred, and then the solvent is removed, dried and / or calcined, and the silica-metal oxide is obtained. A process for preparing a product support, and a method for producing a palladium-supported catalyst in which palladium is supported on the silica-metal oxide support.

  The present invention is also a method for producing the palladium-supported catalyst, wherein the silica support and the metal oxide precursor are dissolved or dispersed in a solvent and stirred, and then the solvent is removed and calcined to produce the silica-metal oxide. And a method for producing a palladium-supported catalyst in which palladium is supported on the silica-metal oxide support. The metal oxide precursor is, for example, at least one precursor selected from the group consisting of alkoxides, nitrates, carbonates, oxalates, ammonium salts, and hydroxides of metals contained in the metal oxides. is there.

  The present invention provides an α, β-unsaturated aldehyde, an α, β-unsaturated carboxylic acid and an α, β-unsaturated catalyst, characterized in that an olefin is subjected to liquid phase oxidation with molecular oxygen using the palladium-supported catalyst. This is a method for producing an acid anhydride having a saturated carboxylic acid skeleton.

  The present invention also provides an α, β-unsaturated carboxylic acid and an α, β-unsaturated, characterized in that α, β-unsaturated aldehyde is subjected to liquid phase oxidation with molecular oxygen using the palladium-supported catalyst. This is a method for producing an acid anhydride having a carboxylic acid skeleton.

  According to the palladium-supported catalyst of the present invention, the activity of the liquid phase oxidation reaction of an olefin or an α, β-unsaturated aldehyde is enhanced, and an acid having an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton. Anhydrides can be produced with high selectivity.

  Further, according to the method for producing a palladium-supported catalyst of the present invention, the activity of the liquid phase oxidation reaction of olefin or α, β-unsaturated aldehyde is high, and α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid are produced. A palladium-supported catalyst capable of highly selectively producing an acid anhydride having an acid skeleton can be produced.

  Furthermore, when the palladium-supported catalyst of the present invention is used, an acid anhydride having an α, β-unsaturated aldehyde, an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton is converted from an olefin into an α, β. -An α, β-unsaturated carboxylic acid and an acid anhydride having an α, β-unsaturated carboxylic acid skeleton can be produced with high activity from an unsaturated aldehyde, and the α, β-unsaturated carboxylic acid and α, β -An acid anhydride having an unsaturated carboxylic acid skeleton can be produced with high selectivity. In addition, since dissolved components do not coexist, it is easy to handle in terms of process.

  The palladium-supported catalyst of the present invention is characterized in that palladium is supported on a silica-metal oxide support in which a metal oxide is contained in silica. This catalyst is used as a catalyst for the liquid phase oxidation reaction of olefins or α, β-unsaturated aldehydes. Specifically, liquid phase oxidation of olefin with molecular oxygen produces α, β-unsaturated aldehyde, α, β-unsaturated carboxylic acid and acid anhydride having α, β-unsaturated carboxylic acid skeleton. Catalyst, or α, β-unsaturated aldehyde is subjected to liquid phase oxidation with molecular oxygen to produce α, β-unsaturated carboxylic acid and acid anhydride having α, β-unsaturated carboxylic acid skeleton Used as a catalyst.

  By using the palladium-supported catalyst of the present invention for the liquid phase oxidation reaction of olefins or α, β-unsaturated aldehydes, the activity of the liquid phase oxidation reaction is increased, and α, β-unsaturated carboxylic acid and α, β-unsaturated acid are increased. An acid anhydride having a saturated carboxylic acid skeleton can be obtained with high selectivity.

  The silica-metal oxide support used in the present invention is preferably prepared by previously mixing and / or supporting a metal oxide on a silica support. The palladium-supported catalyst of the present invention is preferably prepared by supporting palladium on a silica-metal oxide support. With such a configuration, it is presumed that the dispersibility of palladium can be maintained by interaction with the metal oxide (such as an electronic effect at the interface), and the effects of the present invention can be achieved. The presence of palladium on the silica support and palladium on the metal oxide supported on the silica support and / or palladium on the metal oxide released from the silica support in a well-balanced manner is effective for the expression of activity. I think.

The specific surface area of the silica support used for the preparation of the silica-metal oxide support is preferably 10 m ² / g or more, more preferably 50 m ² / g or more, and still more preferably 100 m ² / g or more. Also, the specific surface area is preferably 2000 m ² / g or less, more preferably 1500 m ² / g, more preferably 1000 m ² / g or less. The specific surface area of the silica support can be measured by a nitrogen gas adsorption method. If the specific surface area of the silica carrier is too small, the dispersibility of the supported palladium may be impaired, leading to a significant decrease in activity. If the specific surface area is too large, the mechanical strength may be decreased. Furthermore, the average particle diameter (mode diameter) of the silica carrier used in the present invention is preferably 5 μm or more, more preferably 10 μm or more. The average particle diameter is preferably 2 mm or less, and more preferably 1 mm or less.

  The metal oxide is preferably at least one metal oxide selected from the group consisting of antimony trioxide, molybdenum trioxide, tin (IV) oxide, titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, and germanium dioxide. . When these metal oxides are mixed and / or supported on a silica support, in the liquid phase oxidation of an olefin or α, β-unsaturated aldehyde using molecular oxygen, compared to the case where palladium is supported only on the silica support. The activity is increased, and an acid anhydride having an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton can be produced with high selectivity.

  Further, the total mass of the metal oxide mixed and supported on the silica-metal oxide support used in the palladium-supported catalyst of the present invention is a mass percentage (referred to as a metal oxide content) with respect to the mass of the silica support. 0.1 mass percent or more is preferable, 0.5 mass percent or more is more preferable, and 1.0 mass percent or more is more preferable. The mass percentage is preferably 100 mass percent or less, more preferably 75 mass percent or less, and further preferably 50 mass percent or less. If the amount of the mixed and supported metal oxide is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the activity may be reduced.

  In the palladium-supported catalyst of the present invention, palladium is supported on the silica-metal oxide support. Palladium is preferably zero-valent. The palladium loading ratio (mass percent of palladium with respect to the mass of the silica support) is preferably 1 mass percent or more, more preferably 2 mass percent or more, and further preferably 3 mass percent or more. The loading is preferably 100% by mass or less, preferably 75% by mass or less, and more preferably 50% by mass or less.

  In the palladium-supported catalyst of the present invention, the mass ratio (Pd / metal oxide) between the supported palladium and the metal oxide contained in the silica-metal oxide support is preferably 0.05 to 50.

  The silica-metal oxide support used in the palladium-supported catalyst of the present invention is prepared, for example, by dissolving or dispersing the silica support and metal oxide in a solvent, stirring, removing the solvent, and drying and / or firing. it can. Although there is no restriction | limiting in particular in the solvent to be used, From the surface which suppresses melt | dissolution to the solvent of a silica support | carrier, it is preferable to use the solvent whose pH is 9 or less. The metal oxide may be dispersed in a solvent, or all or part of it may be dissolved in the solvent. There is no restriction | limiting in particular also in the removal method of a solvent, Filtration, evaporation, dry up, centrifugation, etc. can be used. Drying may be performed as necessary, and the drying conditions are not particularly limited, and a general box-type dryer can be used. Firing may be performed as necessary, and may be performed using a muffle furnace or the like at a temperature equal to or higher than the drying temperature and a temperature of 800 ° C. or lower with little change in the structure of the silica support. The firing time can be appropriately selected between 0.5 hour and 24 hours.

  In the present invention, the silica-metal oxide support can also be prepared by dissolving or dispersing the silica support and the metal oxide precursor in a solvent and stirring, then removing the solvent and firing. The metal oxide precursor is preferably at least one selected from the group consisting of alkoxides, nitrates, carbonates, oxalates, ammonium salts, and hydroxides of metals contained in the metal oxide. Although there is no restriction | limiting in particular in the solvent to be used, From the surface which suppresses melt | dissolution to the solvent of a silica support | carrier, it is preferable to use the solvent whose pH is 9 or less. The metal oxide precursor may be dispersed in a solvent, or all or a part of it may be dissolved in the solvent. There is no restriction | limiting in particular also in the removal method of a solvent, Filtration, evaporation, dry up, centrifugation, etc. can be used. Drying may be performed as necessary, and the drying conditions are not particularly limited, and a general box-type dryer can be used. When a metal oxide precursor is used, firing is indispensable in order to make the precursor a metal oxide. The calcination temperature is preferably a temperature equal to or higher than the drying temperature, preferably equal to or higher than the decomposition temperature of the precursor, and a temperature equal to or lower than 800 ° C. with little structural change of the silica support. The decomposition temperature of the precursor can be measured using a thermal mass spectrometer. The firing time can be appropriately selected between 0.5 hour and 24 hours.

  The palladium-supported catalyst can be obtained by supporting palladium on a silica-metal oxide support. For example, it can be carried out by a method in which a palladium raw material having an oxidized palladium atom is supported on a silica-metal oxide support and then reduced with a reducing agent. Catalyst preparation methods such as impregnation method (adsorption method, pore filling method, incipient wetness method, evaporation to dryness method, spray method), ion exchange method, etc. A general method can be used.

  In the silica-metal oxide support produced in advance, the metal oxide is expected to be strongly bonded to the silica to some extent by heat treatment or the like. It is presumed that liberation from the metal oxide support is suppressed by supporting palladium on such a silica-metal oxide support. When a metal oxide having a particle size smaller than that of the support is used, the metal oxide released from the catalyst has a small particle size. When a large amount of such a metal oxide having a small particle size is liberated, operational problems such as a decrease in filterability between the catalyst and the reaction solution and outflow of the catalyst out of the reaction system may occur. The presence or absence or proportion of the small particle size component released from the catalyst can be determined from the volume-based particle size distribution measured with a laser diffraction particle size distribution analyzer. The proportion of particles having a size of 10 μm or less thus obtained is preferably 8% or less, more preferably 6% or less, and particularly preferably 4% or less.

  As the palladium raw material, palladium nitrate, palladium acetate, dinitrodiammine palladium, bis (acetylacetonato) palladium, tetraammine palladium salt, palladium hydroxide, etc. can be used. Many compounds are less preferred because they significantly reduce catalyst performance. After the palladium raw material is supported on the silica-metal oxide support by the above-described method, it is fired for thermal decomposition of the palladium raw material. The firing atmosphere is usually air, but an inert gas such as nitrogen may be used. The firing temperature can be appropriately selected in consideration of the decomposition temperature of the palladium raw material to be used, the firing atmosphere, and the like, and the firing time can also be appropriately selected between 0.5 hour and 24 hours.

  In addition, in the palladium supported catalyst of this invention, metal components other than palladium can be included in the silica-metal oxide support manufactured beforehand. By containing a metal component, the target product can be produced with higher activity or higher selectivity than when only palladium is supported on a silica-metal oxide support. Examples of metal components other than palladium include antimony, tellurium, thallium, lead, bismuth and the like. Two or more metal components other than palladium can be contained.

  When a metal component other than palladium is contained in a silica-metal oxide support produced in advance, the metal component is 0.002 mol per 1.0 mol of palladium, although it depends on the type of metal component and the catalyst preparation method. It is preferable to contain the above, and it is more preferable to contain 0.003 mol or more. Moreover, it is preferable that a metal component contains 0.5 mol or less with respect to 1.0 mol of palladium, and it is more preferable to contain 0.4 mol or less.

  The metal component other than palladium needs to carry a metal compound such as a corresponding metal salt or oxide on a carrier. The method for supporting the metal compound at that time is not particularly limited, but can be carried out in the same manner as the method for supporting the palladium salt.

The calcined palladium raw material is reduced by a reducing agent. Any reducing agent can be used as long as it has the ability to reduce the oxidized palladium atom, but ethanol, 1-propanol, 2-propanol, ethylene glycol, propylene glycol, formaldehyde, formic acid, ascorbic acid, hydrazine, Preference is given to at least one compound selected from the group consisting of hydrogen, ethylene, propylene, 1-butene, 2-butene and isobutylene. The reduction may be performed in either the gas phase or the liquid phase, but the reduction in the liquid phase is more preferable.
During the reduction of the palladium-supported catalyst, a part of the metal oxide contained in the silica-metal oxide used as a support in the present invention may be reduced by a reducing agent. Even when part of such a metal oxide is reduced, the effect of the present invention appears if the metal oxide remains. In the present invention, by using a silica-metal oxide support, it is assumed that the effect is achieved by maintaining the dispersibility of palladium by the interaction between palladium and the metal oxide (such as electronic effects at the interface). Yes. The interaction between palladium and metal oxide is presumed to be manifested in the palladium loading or firing step. Therefore, it is speculated that the dispersibility of palladium is maintained even when a part of the metal oxide is reduced in the reduction step. The oxidation / reduction state of the metal oxide can be confirmed by, for example, X-ray photoelectron spectroscopy (XPS).

  The obtained palladium-supported catalyst may be washed before being subjected to a liquid phase oxidation reaction. In particular, it is preferable that the palladium-supported catalyst obtained by reduction in the liquid phase is sufficiently washed with water, warm water, or a solvent because the reaction may be inhibited if the reducing agent remains. The method and the number of times of washing are not particularly limited, but it is preferable to wash to such an extent that the reducing agent can be sufficiently removed. The washed palladium-supported catalyst may be collected and dried before use. When drying, drying under reduced pressure or inert gas atmosphere is preferred.

  The physical properties of the prepared palladium-supported catalyst can be confirmed by powder X-ray diffraction method, CO pulse adsorption method, electron microscope (TEM, SEM) observation, nitrogen gas adsorption method, particle size distribution measurement and the like.

  Next, a method for performing a liquid phase oxidation reaction of an olefin or an α, β-unsaturated aldehyde using the palladium-supported catalyst of the present invention will be described. As a method utilizing such a reaction, for example, a method of producing an acid anhydride having an α, β-unsaturated aldehyde, an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton from an olefin. And a method for producing an α, β-unsaturated carboxylic acid and an acid anhydride having an α, β-unsaturated carboxylic acid skeleton from an α, β-unsaturated aldehyde. These production methods will be described below. .

  Examples of the olefin as a raw material include propylene, isobutylene, 2-butene, α-methylstyrene, β-methylstyrene, and the like, among which propylene and isobutylene are preferable. Examples of the raw α, β-unsaturated aldehyde include acrolein, methacrolein, crotonaldehyde (β-methylacrolein), cinnamaldehyde (β-phenylacrolein), and among them, acrolein and methacrolein are preferable. The raw material olefin or α, β-unsaturated aldehyde may contain a small amount of saturated hydrocarbon and / or lower saturated aldehyde as impurities.

  The α, β-unsaturated aldehyde and α, β-unsaturated carboxylic acid produced in the present invention have the same carbon skeleton as the olefin and α, β-unsaturated aldehyde. In addition, the acid anhydride having an α, β-unsaturated carboxylic acid skeleton produced in the present invention has the same carbon skeleton as that of the olefin and the α, β-unsaturated aldehyde as at least one carboxylic acid skeleton. A π-allyl type intermediate in which α, β-unsaturated carboxylic acid, which is an oxidation product of olefin and α, β-unsaturated aldehyde, is usually formed between palladium and α, β-unsaturated aldehyde Are both α, β-unsaturated carboxylic anhydrides having the same carboxylic acid skeleton.

  On the other hand, when a carboxylic acid different from the generated α, β-unsaturated carboxylic acid is used as a reaction solvent, a π-allyl type intermediate formed between palladium and an α, β-unsaturated aldehyde An anhydride having a different carboxylic acid skeleton can be produced by attack of the carboxylic acid on the surface. Examples thereof include acid anhydrides of methacrylic acid and carboxylic acids other than methacrylic acid such as acetic acid, propionic acid, acrylic acid, and butyric acid.

  The liquid phase oxidation reaction in the present invention may be carried out in either a continuous type or a batch type, but in view of productivity, the continuous type is preferred industrially.

  The concentration of the olefin or α, β-unsaturated aldehyde which is a raw material used in the liquid phase oxidation reaction in the present invention is preferably 0.1 mass percent or more with respect to the mass of the solvent present in the reactor. 5 mass percent or more is more preferable. The raw material concentration is preferably 30% by mass or less, and more preferably 20% by mass or less.

  As the source of molecular oxygen used in the liquid phase oxidation reaction in the present invention, air is economical and preferable, but pure oxygen or a mixed gas of pure oxygen and air can be used. Alternatively, a mixed gas obtained by diluting pure oxygen with nitrogen, carbon dioxide, water vapor, or the like can be used. These gases are usually supplied in a pressurized state in a reaction vessel such as an autoclave. The amount of molecular oxygen used is preferably at least 0.1 mol, more preferably at least 0.2 mol, even more preferably at least 0.3 mol, based on 1 mol of the raw material olefin or α, β-unsaturated aldehyde. . The amount of molecular oxygen used is preferably 20 mol or less, more preferably 15 mol or less, and even more preferably 10 mol or less.

  Examples of the solvent used in the liquid phase oxidation reaction in the present invention include t-butanol, cyclohexanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid and At least one organic solvent selected from the group consisting of iso-valeric acid is preferred. In particular, in order to more selectively produce an acid anhydride having an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton, it is preferable to coexist water in these organic solvents. The amount of water to be coexisted is not particularly limited, but when it is desired to more selectively produce an α, β-unsaturated carboxylic acid, it is preferably 2% by mass or more based on the total mass of the organic solvent and water. A mass percentage or more is more preferable. Further, the amount of water to be coexisted is preferably 70% by mass or less, and more preferably 50% by mass or less. The mixture of the organic solvent and water is desirably in a uniform state, but may be in a non-uniform state.

  When performing the liquid phase oxidation reaction using the palladium-supported catalyst in the present invention, a suspension bed reactor is usually used, but a fixed bed reactor may be used. The amount of the palladium-supported catalyst is preferably 0.1 mass percent or more, more preferably 0.5 mass percent or more, and more preferably 1 mass percent or more based on the solution present in the reactor. The amount of the palladium-supported catalyst is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less.

  The reaction temperature and reaction pressure in the liquid phase oxidation reaction of the present invention are appropriately selected depending on the solvent and raw materials used. The reaction temperature is preferably 30 ° C. or higher, more preferably 50 ° C. or higher. The reaction temperature is preferably 200 ° C. or lower, and more preferably 150 ° C. or lower. The reaction pressure is preferably 0 MPa (gauge pressure; hereinafter, all pressures are expressed as gauge pressures) or more, and more preferably 0.5 MPa or more. The reaction pressure is preferably 10 MPa or less, and more preferably 7 MPa or less.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to an Example. In the following Examples and Comparative Examples, “part” means “part by mass”.

(Analysis of raw materials and products)
Raw materials and products were analyzed by high performance liquid chromatography (hereinafter abbreviated as HPLC) or gas chromatography (hereinafter abbreviated as GC).

"Analysis by HPLC"
In the analysis by HPLC, only the target product, α, β-unsaturated aldehyde, α, β-unsaturated carboxylic acid and acid anhydride having an α, β-unsaturated carboxylic acid skeleton, were analyzed. Here, the obtained total product amount is A (mol), the production amount of α, β-unsaturated aldehyde is B (mol), the production amount of α, β-unsaturated carboxylic acid is C (mol) and α, β. -The production amount of the acid anhydride having an unsaturated carboxylic acid skeleton is D (mol), and the mass of the produced α, β-unsaturated carboxylic acid is E (g).
α, β-unsaturated aldehyde selectivity, α, β-unsaturated carboxylic acid selectivity and α, β-unsaturated carboxylic acid anhydride selectivity, α, β-unsaturated carboxylic acid selectivity Productivity is defined as follows. The mass of palladium metal in the catalyst is F (g) and the reaction time is G (h).
Selectivity (%) of α, β-unsaturated aldehyde = B / A × 100
Selectivity (%) of α, β-unsaturated carboxylic acid = C / A × 100
Selectivity (%) of acid anhydride having α, β-unsaturated carboxylic acid skeleton = D / A
Total product amount A (mol) = B + C + D
Productivity of α, β-unsaturated carboxylic acid (g / gPd / h) = (E / F / G)

"Analysis by GC"
In the analysis by GC, an olefin, an α, β-unsaturated aldehyde, an α, β-unsaturated carboxylic acid and an acid anhydride having an α, β-unsaturated carboxylic acid skeleton were analyzed. Here, the amount of olefin used as a reaction raw material is X (mole), the reacted olefin is Y (mole), the amount of α, β-unsaturated aldehyde produced is B (mole), α, β-unsaturated carboxylic acid. The amount of acid produced is C (mole), the amount of acid anhydride having an α, β-unsaturated carboxylic acid skeleton is D (mole), and the mass of the produced α, β-unsaturated carboxylic acid is E (g). And
Reaction rate of olefin or α, β-unsaturated aldehyde, selectivity of α, β-unsaturated aldehyde, selectivity of α, β-unsaturated carboxylic acid and acid anhydride having α, β-unsaturated carboxylic acid skeleton The productivity of α, β-unsaturated carboxylic acid is defined as follows. The mass of palladium metal in the catalyst is F (g) and the reaction time is G (h).
Reaction rate of olefin or α, β unsaturated aldehyde = Y / X × 100
Selectivity (%) of α, β-unsaturated aldehyde = B / Y × 100
Selectivity (%) of α, β-unsaturated carboxylic acid = C / Y × 100
Selectivity (%) of acid anhydride having α, β-unsaturated carboxylic acid skeleton = D / Y
Productivity of α, β-unsaturated carboxylic acid (g / gPd / h) = (E / F / G)

  However, in any case of the analysis by HPLC and the analysis by GC, all the mole numbers obtained by the analysis are calculated based on the carbon number of the raw material. That is, in the liquid phase oxidation reaction of isobutylene in the following examples / comparative examples, the calculation is based on the number of carbon atoms of 4, and the number of carbon atoms of methacrylic acid anhydride is 8. The number of moles is doubled.

(Measurement of catalyst particle size distribution)
The particle size distribution of the catalyst was measured using a laser diffraction particle size distribution measuring device (manufactured by Shimadzu Corporation, trade name: SALD-7000). Pure water was used as the dispersion medium, and the measurement was performed immediately after ultrasonic irradiation for 1 minute. The ratio of particles having a particle size of 10 μm or less was calculated from the volume-based particle size distribution obtained by measurement.

[Example 1]
(Catalyst preparation)
In a solution obtained by dissolving 5.9 parts of titanium isopropoxide in 60.0 parts of 1-propanol, silica support (manufactured by Fuji Silysia, BET specific surface area 490 m ² / g, total pore volume 0.70 ml / g) 20.0 The mixture was added and stirred at 50 ° C. for 1 hour on a hot stirrer. Then, the solvent was distilled off under reduced pressure by a rotary evaporator (bath temperature 50 ° C.). The obtained powder was air baked in a muffle furnace at 600 ° C. for 3 hours to obtain a silica-titanium oxide support in which titanium oxide was supported on the silica support.

  To a solution obtained by dissolving 1.05 parts of palladium acetate (manufactured by NE Chemcat) in 50.0 parts of acetic acid, 10.0 parts of the silica-titanium oxide support obtained above was added and stirred for 15 minutes. The solvent was distilled off under reduced pressure using a rotary evaporator (bath temperature 80 ° C.). The obtained brown powder was air baked in a muffle furnace at 450 ° C. for 3 hours. Furthermore, 50.0 parts of a formalin solution (37% by mass aqueous formaldehyde solution) was added to the obtained powder, and reduction was performed on a hot stirrer at 70 ° C. for 2 hours. The black powder was separated by suction filtration while washing with 100 parts of warm water at 60 ° C. This was dried at 100 ° C. for 3 hours to obtain a palladium-supported catalyst. The palladium-supported catalyst had a titanium oxide support of 8.3% by mass, and the palladium support of 5.0% by mass.

(Reaction evaluation)
1.0 part of the palladium-supported catalyst obtained by the above method was charged into an autoclave having a capacity of 50 cc equipped with a heater (made by pressure-resistant glass industry, model: TPR3-VS2-SV), and a 75% by mass aqueous tertiary butanol solution 20 0.0 parts and a stir bar were added and the vessel was sealed. An autoclave was set on the magnetic stirrer, and stirring was started at 1200 rpm. An aspirator was connected to the autoclave outlet, the valve was opened, and the pressure inside the container and the line was reduced by suction, and then the valve was once closed. The gas introduction line was connected to an autoclave, and 0.25 MPa of isobutylene gas was introduced from a liquefied isobutylene cylinder kept at 35 ° C. Further, the introduction line was switched to nitrogen, and after introducing nitrogen to a total pressure of 2.5 MPa, the heater was set at 100 ° C. and heating was started. After reaching 100 ° C., the introduction line was switched to air, and air was introduced to a total pressure of 5.0 MPa. The reaction was carried out for 120 minutes from the time when air was introduced. After completion of the reaction, the reactor was cooled with ice water, and when the temperature reached 20 ° C., stirring was stopped and the pressure was gradually released. When the pressure was returned to normal pressure, the vessel was opened, the reaction solution was recovered, the catalyst was removed by a membrane filter, and 1 μL was introduced into HPLC for analysis.

  At this time, the total amount of products was 3.42 mmol, the amount of methacrolein was 1.39 mmol, the amount of methacrylic acid was 1.95 mmol, and the amount of methacrylic anhydride was 0.09 mmol. The selectivity of methacrolein was 40.6%, the selectivity of methacrylic acid was 56.9%, and the selectivity of methacrylic anhydride was 2.5%. The results are shown in Table 1.

[Example 2]
(Catalyst preparation)
20.0 parts of silica support (manufactured by Fuji Silysia, BET specific surface area 490 m ² / g, total pore volume 0.70 ml / g) is added to a dispersion obtained by dispersing 1.2 parts of antimony trioxide in 100 parts of pure water. The mixture was heated and stirred at 80 ° C. for 2 hours on a hot stirrer. Thereafter, water as a solvent was evaporated to dryness at 100 ° C., and further dried overnight at 100 ° C. to obtain a silica-antimony trioxide carrier in which antimony trioxide was mixed with the silica carrier. Palladium was supported on this silica-antimony trioxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. The palladium-supported catalyst had an antimony trioxide loading of 6.0% by mass and a palladium loading of 5.0% by mass. The proportion of particles having a particle size of 10 μm or less in this catalyst was 3.3%.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 4.10 mmol, the amount of methacrolein was 2.22 mmol, the amount of methacrylic acid was 1.85 mmol, and the amount of methacrylic anhydride was 0.03 mmol. The selectivity of methacrolein was 54.1%, the selectivity of methacrylic acid was 45.2%, and the selectivity of methacrylic anhydride was 0.8%. The results are shown in Table 1.

[Example 3]
(Catalyst preparation)
A silica-molybdenum trioxide support in which molybdenum trioxide was mixed with the silica support was obtained in the same manner as in Example 2 except that 1.5 parts of molybdenum trioxide was used. Palladium was supported on this silica-molybdenum trioxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the loading rate of molybdenum trioxide was 7.5% by mass, and the loading rate of palladium was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. The total amount of products at this time was 5.25 mmol, the amount of methacrolein was 2.86 mmol, the amount of methacrylic acid was 2.38 mmol, and the amount of methacrylic anhydride was 0.01 mmol. The selectivity of methacrolein was 54.5%, the selectivity of methacrylic acid was 45.3%, and the selectivity of methacrylic anhydride was 0.2%. The results are shown in Table 1.

[Example 4]
(Catalyst preparation)
A silica-tantalum oxide support in which tantalum oxide is supported on a silica support was obtained in the same manner as in Example 1 except that 2.8 parts of tantalum hydroxide was used. Palladium was supported on this silica-tantalum oxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the tantalum oxide support was 13.9% by mass, and the palladium support was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 3.97 mmol, the amount of methacrolein was 2.00 mmol, the amount of methacrylic acid was 1.92 mmol, and the amount of methacrylic anhydride was 0.06 mmol. The selectivity of methacrolein was 50.3%, the selectivity of methacrylic acid was 48.2%, and the selectivity of methacrylic anhydride was 1.5%. The results are shown in Table 1.

[Example 5]
(Catalyst preparation)
In a dispersion obtained by dispersing 4.8 parts of niobium ammonium oxalate in 100 parts of pure water, 20.0 parts of a silica carrier (manufactured by Fuji Silysia, BET specific surface area of 490 m ² / g, total pore volume of 0.70 ml / g) is added. In addition, the mixture was stirred for 1 hour at 50 ° C. on a hot stirrer. Thereafter, water as a solvent was evaporated to dryness at 100 ° C., followed by air baking in a muffle furnace at 600 ° C. for 3 hours to obtain a silica-niobium oxide carrier in which niobium oxide was supported on a silica carrier. Palladium was supported on this silica-niobium oxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. The palladium supported catalyst had a niobium oxide loading of 7.2 mass% and a palladium loading of 5.0 mass%.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 3.98 mmol, the amount of methacrolein was 2.19 mmol, the amount of methacrylic acid was 1.77 mmol, and the amount of methacrylic anhydride was 0.02 mmol. The selectivity of methacrolein was 54.9%, the selectivity of methacrylic acid was 44.5%, and the selectivity of methacrylic anhydride was 0.6%. The results are shown in Table 1.

[Example 6]
(Catalyst preparation)
A silica-tungsten oxide carrier in which tungsten oxide was mixed with a silica carrier was obtained in the same manner as in Example 2 except that 1.3 parts of tungsten oxide was used. Palladium was supported on this silica-tungsten oxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. The supported rate of tungsten oxide in this palladium-supported catalyst was 6.3% by mass, and the supported rate of palladium was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 3.44 mmol, the amount of methacrolein was 2.11 mmol, the amount of methacrylic acid was 1.31 mmol, and the amount of methacrylic anhydride was 0.02 mmol. The selectivity of methacrolein was 61.3%, the selectivity of methacrylic acid was 38.0%, and the selectivity of methacrylic anhydride was 0.7%. The results are shown in Table 1.

[Example 7]
(Catalyst preparation)
A silica-germanium dioxide support in which germanium dioxide was mixed with a silica support was obtained in the same manner as in Example 2 except that 1.4 parts of germanium dioxide was used. Palladium was supported on this silica-germanium dioxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the germanium dioxide loading was 7.2% by mass, and the palladium loading was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. The total amount of products at this time was 3.41 mmol, the amount of methacrolein produced was 1.88 mmol, the amount of methacrylic acid produced was 1.49 mmol, and the amount of methacrylic anhydride produced was 0.04 mmol. The selectivity of methacrolein was 55.2%, the selectivity of methacrylic acid was 43.6%, and the selectivity of methacrylic anhydride was 1.2%. The results are shown in Table 1.

[Example 8]
(Catalyst preparation)
A silica-tellurium oxide support in which tellurium oxide was mixed with a silica support was obtained in the same manner as in Example 2 except that 0.2 part of tellurium oxide was used. Palladium was supported on the silica-tellurium oxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the tellurium oxide support was 1.1% by mass, and the palladium support was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 5.20 mmol, the amount of methacrolein was 3.34 mmol, the amount of methacrylic acid was 1.46 mmol, and the amount of methacrylic anhydride was 0.40 mmol. The selectivity of methacrolein was 64.3%, the selectivity of methacrylic acid was 28.1%, and the selectivity of methacrylic anhydride was 7.6%. The results are shown in Table 1.

[Example 9]
(Catalyst preparation)
A silica-tin (IV) oxide support in which tin (IV) oxide was mixed with a silica support was obtained in the same manner as in Example 2 except that 1.2 parts of tin (IV) oxide was used. Palladium was supported on this silica-tin (IV) oxide support in the same manner as in Example 1 to obtain a palladium-supported catalyst. The palladium-supported catalyst had a tin (IV) oxide loading of 6.4% by mass, and the palladium loading was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 4.60 mmol, the amount of methacrolein was 2.56 mmol, the amount of methacrylic acid was 1.98 mmol, and the amount of methacrylic anhydride was 0.06 mmol. The selectivity of methacrolein was 55.6%, the selectivity of methacrylic acid was 43.1%, and the selectivity of methacrylic anhydride was 1.3%. The results are shown in Table 1.

[Example 10]
(Catalyst preparation)
The catalyst described in Example 1 was used.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that 1.0 part of methacrolein was used instead of isobutylene. The total amount of products at this time was 7.96 mmol, the amount of methacrylic acid produced was 5.13 mmol, and the amount of methacrylic anhydride produced was 2.83 mmol. The selectivity of methacrylic acid was 64.4%, and the selectivity of methacrylic anhydride was 35.6%. The results are shown in Table 1.

[Comparative Example 1]
(Catalyst preparation)
Palladium was supported on a silica support (Fuji Silysia, BET specific surface area 490 m ² / g, total pore volume 0.70 ml / g) in the same manner as in Example 1 to obtain a palladium supported catalyst. The palladium loading on this palladium supported catalyst was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 1 except that the palladium-supported catalyst prepared by the above method was used. At this time, the total amount of products was 2.00 mmol, the amount of methacrolein was 1.77 mmol, the amount of methacrylic acid was 0.23 mmol, and the amount of methacrylic anhydride was 0 mmol. The selectivity of methacrolein was 88.7%, the selectivity of methacrylic acid was 11.3%, and the selectivity of methacrylic anhydride was 0%. The results are shown in Table 1.

[Example 11]
(Catalyst preparation)
In a solution obtained by dissolving 3.6 parts of titanium isopropoxide in 60.0 parts of 1-propanol, silica support (manufactured by Fuji Silysia, BET specific surface area 490 m ² / g, total pore volume 0.70 ml / g) 20.0 The mixture was added and stirred at 50 ° C. for 1 hour on a hot stirrer. Then, the solvent was distilled off under reduced pressure by a rotary evaporator (bath temperature 50 ° C.). The obtained powder was air baked in a muffle furnace at 600 ° C. for 3 hours to obtain a silica-titanium oxide support in which titanium oxide was supported on the silica support.
To 20.0 parts of the silica-titanium oxide support obtained above, a solution of 2.1 parts of palladium acetate (manufactured by NE Chemcat) and 0.22 parts of telluric acid in 100.0 parts of acetic acid was added, After stirring for 15 minutes, the solvent was distilled off under reduced pressure using a rotary evaporator (bath temperature 80 ° C.). The obtained brown powder was air baked in a muffle furnace at 450 ° C. for 3 hours. Further, 100.0 parts of a formalin solution (37% by mass formaldehyde aqueous solution) was added to the obtained powder, and reduction was performed on a hot stirrer at 70 ° C. for 2 hours. The black powder was separated by suction filtration while washing with 200 parts of warm water at 60 ° C. This was dried at 100 ° C. for 3 hours to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the support rate of titanium oxide was 5.0% by mass, the support rate of palladium was 5.0% by mass, and the support rate of tellurium was 0.6% by mass.

(Reaction evaluation)
10.56 parts (0.5 parts as palladium) of the palladium-supported catalyst obtained by the above method was charged into an autoclave (model: LC-3, manufactured by Toyo Kodan Co., Ltd.) having an internal volume of 330 ml, and 75 mass as a reaction solvent. The autoclave was sealed by adding 100 parts of a% tertiary butanol aqueous solution and 200 ppm of p-methoxyphenol as a radical trapping agent to the reaction solution. Next, 6.5 parts of isobutylene was introduced, stirring (rotation speed: 1000 rpm) was started, and the temperature was raised to 110 ° C. After completion of the temperature increase, nitrogen was introduced into the autoclave to an internal pressure of 2.4 MPa, and then compressed air was introduced to an internal pressure of 4.8 MPa. When the internal pressure decreased by 0.2 MPa during the reaction (internal pressure 4.6 MPa), the operation of introducing 0.2 MPa of oxygen was repeated, and the total amount of oxygen added was 2.0 MPa. The reaction time was 26 minutes.

After completion of the reaction, the inside of the autoclave was cooled in an ice water bath. A gas collection bag was attached to the gas outlet of the autoclave, and the pressure in the reactor was released while collecting the gas that was opened by opening the gas outlet. The reaction solution containing the catalyst was taken out from the autoclave, the catalyst was separated with a membrane filter, and the reaction solution was recovered. The recovered reaction solution and the collected gas were analyzed by gas chromatography.
The reacted isobutylene was 92.42 mmol, the amount of methacrolein produced was 25.90 mmol, the amount of methacrylic acid produced was 30.84 mmol, and the amount of methacrylic anhydride produced was 1.99 mmol. The selectivity of methacrolein was 32.1%, the selectivity of methacrylic acid was 38.2%, and the selectivity of methacrylic anhydride was 18.6%. The results are shown in Table 2.

[Example 12]
(Catalyst preparation)
To 0.4 part of tin tartrate, 100 parts of a 10% by weight aqueous tartaric acid solution was added and stirred at 80 ° C. for 30 minutes on a hot stirrer. To this solution was added 20.0 parts of a silica support (manufactured by Fuji Silysia, BET specific surface area 490 m ² / g, total pore volume 0.70 ml / g), and the mixture was heated and stirred at 80 ° C. for 1 hour on a hot stirrer. Then, the solvent was distilled off under reduced pressure by a rotary evaporator (bath temperature 80 ° C.). The obtained powder was air baked in a muffle furnace at 600 ° C. for 3 hours to obtain a silica-tin oxide support in which tin oxide was supported on the silica support. Palladium and tellurium were supported on 20.0 parts of this silica-tin oxide support in the same manner as in Example 11 to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the support ratio of tin oxide was 1.1 mass%, the support ratio of palladium was 5.0 mass%, and the support ratio of tellurium was 0.6 mass%.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 11 except that 10.56 parts of palladium-supported catalyst prepared by the above method (0.5 parts as palladium) was used. The reaction was completed when the total amount of oxygen reached 2.0 MPa. The reaction time was 25 minutes. At this time, the reacted isobutylene was 78.58 mmol, the amount of methacrolein produced was 32.33 mmol, the amount of methacrylic acid produced was 26.15 mmol, and the amount of methacrylic anhydride produced was 9.97 mmol. The selectivity of methacrolein was 41.1%, the selectivity of methacrylic acid was 33.3%, and the selectivity of methacrylic anhydride was 12.7%. The results are shown in Table 2.

[Example 13]
(Catalyst preparation)
100 parts of pure water was added to 1.2 parts of ammonium molybdate and dissolved. 20.0 parts of a silica carrier (manufactured by Fuji Silysia, BET specific surface area 490 m ² / g, total pore volume 0.70 ml / g) was added to this solution, and the mixture was heated and stirred at 50 ° C. for 1 hour on a hot stirrer. Then, the solvent was distilled off under reduced pressure by a rotary evaporator (bath temperature 80 ° C.). The obtained powder was air baked in a muffle furnace at 400 ° C. for 3 hours to obtain a silica-molybdenum oxide support in which molybdenum oxide was supported on the silica support. Palladium and tellurium were supported on 20.0 parts of this silica-molybdenum oxide support in the same manner as in Example 11 to obtain a palladium-supported catalyst. In this palladium-supported catalyst, the molybdenum oxide support was 5.0% by mass, the palladium support was 5.0% by mass, and the tellurium support was 0.6% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 11 except that 10.56 parts of palladium-supported catalyst prepared by the above method (0.5 parts as palladium) was used. The reaction was completed when the total amount of oxygen reached 2.0 MPa. The reaction time was 19 minutes. At this time, the reacted isobutylene was 85.22 mmol, the amount of methacrolein produced was 31.94 mmol, the amount of methacrylic acid produced was 33.24 mmol, and the amount of methacrylic anhydride produced was 7.99 mmol. The selectivity of methacrolein was 39.3%, the selectivity of methacrylic acid was 40.9%, and the selectivity of methacrylic anhydride was 9.8%. The results are shown in Table 2.

[Comparative Example 2]
(Catalyst preparation)
A palladium-supported catalyst was obtained in the same manner as in Comparative Example 1. The palladium loading on this palladium supported catalyst was 5.0% by mass.

(Reaction evaluation)
Reaction evaluation was performed in the same manner as in Example 11 except that 10.5 parts of palladium-supported catalyst prepared by the above method (0.5 parts as palladium) was used. The reaction was completed when the total amount of oxygen reached 2.0 MPa. The reaction time was 33 minutes. At this time, the reacted isobutylene was 82.13 mmol, the amount of methacrolein produced was 23.77 mmol, the amount of methacrylic acid produced was 19.61 mmol, and the amount of methacrylic anhydride produced was 6.55 mmol. The selectivity of methacrolein was 35.6%, the selectivity of methacrylic acid was 31.8%, and the selectivity of methacrylic anhydride was 10.6%. The results are shown in Table 2.

  As described above, by using the palladium-supported catalyst of the present invention, the activity of the liquid phase oxidation reaction of olefin can be enhanced, and α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid skeleton are used. It was found that an acid anhydride having a high yield can be produced with high selectivity.

Claims (2)

Shi silica to tellurium oxide, antimony trioxide, molybdenum trioxide, tin oxide (IV), titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, contains at least one metal oxide selected from the group consisting of germanium dioxide It is silica - the metal oxide support, palladium using the Rupa radium supported catalyst is supported, characterized in that liquid-phase oxidation of olefins by molecular oxygen, alpha, beta-unsaturated aldehyde, alpha, beta A method for producing an acid anhydride having an unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid skeleton . Silica contains at least one metal oxide selected from the group consisting of tellurium oxide, antimony trioxide, molybdenum trioxide, tin (IV) oxide, titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, and germanium dioxide. An α, β-unsaturated carboxylic acid characterized in that α, β-unsaturated aldehyde is subjected to liquid phase oxidation with molecular oxygen using a palladium-supported catalyst in which palladium is supported on a silica-metal oxide support. A process for producing an acid and an acid anhydride having an α, β-unsaturated carboxylic acid skeleton.