JPH02759A - Production of aliphatic o-arylurethane - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as an intermediate raw material for masked isocyanate and aliphatic isocyanate in high yield by reacting an aliphatic primary amine with an aromatic hydroxyl compound and urea while removing the reaction by-product. CONSTITUTION:An aliphatic primary amine is made to react with an aromatic hydroxyl compound and urea at 150-280 deg.C. The reaction is carried out while removing by-produced ammonia from the reaction system in such a manner as to keep the ammonia concentration to <=2wt.%. The amount of the hydroxyl group of the aromatic hydroxyl compound is maintained to >=1mol and that of urea is maintained to >=0.5mol based on 1mol of the amino group of the aliphatic primary amine. Since the process does not use phosgene and carbon monoxide, the objective compound can be produced in one reaction step without causing the problems of corrosion and toxicity, producing large amount of hydrogen chloride gas as a by-product nor using expensive noble metal catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing aliphatic 0-aryl urethane, which is widely used as an intermediate raw material for masked isocyanates and aliphatic isocyanates. For more details,
It is characterized by reacting an aliphatic primary amine with an aromatic hydroxyl compound and urea, and removing by-produced ammonia from the reaction system so that the ammonia concentration in the reaction solution is 2% by weight or less. The present invention relates to a method for producing an aliphatic O-aryl urethane.

(Prior Art) Conventionally, aliphatic 0-aryl urethanes have been produced by reacting aromatic hydroxyl compounds with aliphatic isocyanates [for example, Iwa 1], Keiji, Plastic Materials Course 2, Polyurethane Resins, 175. (Nikkan Kogyo Shimbun series), 1969, K. C. Frisch, "Fundamental Chemistry and Catalysis of Polyurethanes", Polyurethane Technology, p., p. Plines, ed., Interscience Publishers. Publishing, New York, 1969, 11
[page] In this case, the aliphatic isocyanate is obtained by the reaction of the corresponding aliphatic primary amine with phosgene (for example, British Patent No. 1.077, 031).
It has the following drawbacks. This means that highly toxic phosgene is used, a large amount of corrosive hydrogen chloride gas is produced as a by-product, and the product may contain hydrolyzable chlorine compounds, making it extremely difficult to remove this by-product. There are problems such as difficulty in Therefore, the method of reacting an aromatic hydroxyl compound with an aliphatic isocyanate to obtain an aliphatic 0-aryl urethane is not satisfactory.

JP 55-120551 (U.S. Patent No. 4,297.5)
01 specification) publication, aliphatic 0 without using phosgene
- As a method for producing aryl urethane, primary amine, -
A process for oxidative urethanization of carbon oxide and aliphatic alcohols or aromatic hydroxyl compounds using noble metal catalysts is described. However, there are no examples using aromatic hydroxyl compounds, but this method also
Because highly toxic carbon monoxide and expensive precious metal catalysts are used, recovering the catalyst from the product urethane requires complicated operations and a large amount of cost. ing.

Also, in U.S. Patent No. 3,873.553, N-
By reacting an alkyl-N,N'-dialkyl urea, an aromatic hydroxyl compound, and hydrogen chloride gas, O-
A method for making aryl urethanes is described. However, this method also uses corrosive hydrogen chloride gas, consumes expensive and specialized urea compounds, and produces N as a by-product.

Recovery of urethane from N-dialkylamine hydrochloride has the problem of requiring complicated operations and large costs.

On the other hand, US Pat. No. 2,677.698 describes a method for producing aliphatic monourethane that does not use phosgene.
In the first stage, N,N'-dialkyl urea is produced from aliphatic primary amine and urea, and in the second stage, N,N'-dialkyl urea is reacted with a hydroxyl compound to produce aliphatic monourethane, which is produced as a by-product. A method is described in which the primary amine is separated and recovered and returned to the first stage. However, there are no examples using aromatic hydroxyl compounds. However, this method not only has a low yield of urethane but also requires two stages of reaction and equipment for recycling the primary amine, making the process extremely complicated and unsatisfactory for industrial implementation.

Several methods have been proposed for producing aliphatic urethane by reacting an aliphatic primary amine with a hydroxyl compound and urea in one step, but all of the aliphatic urethanes obtained by these methods are For example, 0 that is an aliphatic 〇-alkyl urethane rather than a 0-aryl urethane,
U.S. Pat. No. 2,409,712 describes a process for producing aliphatic O-alkyl monourethanes by reacting an aliphatic primary amine and urea with an aliphatic alcohol. Also, JP-A-55-145657 (West German Patent No. 2.917.493), JP-A-56-1031
No. 52 (West German Patent No. 2,943.551) discloses that an aliphatic primary polyamine is reacted with an aliphatic, alicyclic, or aromatic aliphatic alcohol in the presence of urea or a urea compound,
A method for making aliphatic 0-alkyl polyurethanes is described.

(Problem R to be solved by the invention) However, the aliphatic 0-alkyl urethanes produced by these methods are extremely thermally stable, so it is difficult to decompose them into the corresponding aliphatic isocyanates and alcohols. Therefore, it is not satisfactory for use as an intermediate raw material for Max. German cyanate and aliphatic isocyanate.

In this regard, it has been known that aliphatic 0-aryl urethanes easily decompose into corresponding aliphatic isocyanates and aromatic hydroxyl compounds (for example, "O. Bayer").
Das Diisocyanat-Polyaddit
ions Verfahren + 12 pages, 1963
However, a method for producing an aliphatic 0-aryl urethane from a one-step reaction of an aromatic hydroxyl compound and urea with an aliphatic primary amine has not yet been known.

(Means for Solving the Problem) First, the present inventors investigated a method for producing an aliphatic 0-aryl urethane from the reaction of an aromatic hydroxyl compound and urea with an aliphatic primary amine, and found the following points. I found out. In other words, if this reaction is exemplified by the reaction of an aliphatic primary polyamine with urea and an aromatic monohydroxyl compound, it is reversible and the equilibrium is significantly biased toward the yarn side, as expressed by the following formula 1. Therefore, it is important to remove the by-product ammonia for the reaction to proceed.Secondly, aromatic hydroxyl compounds, which are one type of acid, bind strongly to ammonia, so it is difficult to remove ammonia using normal methods. I found it extremely difficult.

R-(MHz)n +nN1(zcONl(z(in the above formula, n is an integer of 1 or more, R is an aliphatic group, A
r represents an aromatic group) Further, as a result of extensive studies, the present inventors reacted an aromatic hydroxyl compound and urea with an aliphatic primary amine, and the ammonia concentration in the reaction solution was 2% by weight. We have discovered a method for producing aliphatic 0-aryl urethane in high yield by removing by-produced ammonia from the reaction system as shown below, and have completed the present invention.

In other words, the present invention provides a method for converting aliphatic primary amines into aliphatic 0-
A method for producing an aryl urethane includes: a) reacting an aliphatic primary amine with an aromatic hydroxyl compound and urea; b) adding by-produced ammonia to the reaction system so that the ammonia concentration in the reaction solution is 2% by weight or less. The present invention provides a method for producing an aliphatic 0-aryl urethane, characterized in that the reaction is carried out while removing the aliphatic 0-aryl urethane.

In carrying out the present invention, the aromatic hydroxyl compound used may be any compound as long as the hydroxyl group is directly bonded to the aromatic group.For example, phenol; cresol (each isomer ), various alkylphenols such as xylenol (each isomer), ethylphenol (each isomer), propylphenol (each isomer); various alkoxyphenols such as methoxyphenol (each isomer), ethoxyphenol (each isomer), etc. Cheek: Halogenated phenols such as chlorphenol (each isomer), bromophenol (each isomer), dichlorophenol (each isomer), dibromophenol (each isomer); Methylchlorophenol (each isomer), Alkyl and halogen-substituted phenols such as ethylchlorophenol (each isomer), methylbromophenol (each isomer), and ethylbromophenol (each isomer); [However, A is a simple bond, or -〇--5- 3O□--CO--CH
□--C represents a divalent group such as (R2)-, where R is a lower alkyl group, and the aromatic ring is a halogen, alkyl group, alkoxy group, ester group, amide group, cyano group, etc. Various substituted phenols represented by ], which may be substituted with a substituent; Naphthol (each isomer) and various substituted naphthols; Hydroxypyridine (each isomer)
Heteroaromatic hydroxyl compounds such as , hydroxycoumarin (all isomers), hydroxyquinoline (all isomers); aromatic dihydrokymo small compounds such as hydroquinone, resorcinol, catechol, and their alkyl-substituted dihydroxyl compounds; [However, A is just a combination,
or -〇-3-3Oz--Co CHz
Represents a divalent group such as C(R□)-, in which R is a lower alkyl group, and the aromatic ring is a halogen, an alkyl group,
Aromatic dihydroxyl compounds represented by ], which may be substituted with a substituent such as an alkoxy group, ester group, amide group, or cyano group; nitrophenol (each isomer), nitronaphthol (each isomer), etc. Nitro-substituted aromatic hydroxyl compounds; cyano-substituted aromatic dihydroxyl compounds such as cyanophenol (all isomers) and cyanonaphthol (all isomers) are used.

In this way, only one kind of aromatic hydroxyl compound may be used, or two or more kinds of aromatic hydroxyl compounds may be used in combination. Also,
It is preferable to use aromatic monohydroxyl compounds because they can be easily separated by distillation.

Among them, it is more preferable to use phenol having a low boiling point.

In carrying out the present invention, the amount of aromatic hydroxyl compound used is determined by the amount of amino group of the aliphatic primary amine used.
It is preferable to use one mole or more of hydroxyl groups per mole.

This is because if the amount of the aromatic hydroxyl compound is less than 1 mol per amino group of the aliphatic primary amine, a complexly substituted urea compound will be produced as a by-product. A more preferable usage amount is
5 moles or more of hydroxyl group per mole of amino if,
More preferably, the amount is 10 mol or more. Particularly when using an aliphatic primary polyamine and an aromatic polyhydroxyl compound, the closer the number of hydroxyl groups is to 1 mole per 1 mole of amino groups, the more complexly substituted urea compounds are produced as by-products. is 5
Aliphatic 1 used in this sense, preferably more than molar
A preferred combination of a primary amine and an aromatic hydroxyl compound is an aliphatic primary monoamine and an aromatic monohydroxyl compound, or/and an aromatic polyhydroxyl compound,
Alternatively, it is a combination of an aromatic monohydroxyl compound and an aliphatic primary monoamine or/and an aliphatic primary polyamine. Further, the amount of the aromatic hydroxyl compound is preferably 100 mol or less per amino group of the aliphatic primary amine. 1
This is because if the amount exceeds 0.00 mole, the space-time yield will decrease, which is not a good idea for industrial implementation.

The aliphatic primary amine used in the present invention may be any amine in which one or more primary amino groups are bonded to an aliphatic carbon atom; It may also be an aromatic aliphatic primary amine.

Examples of such aliphatic primary monoamines or polyamines include methylamine, ethylamine, propylamine (each isomer), butylamine (each isomer), pentylamine (each isomer), and hexylamine (each isomer).
, dodecylamine (each isomer); aliphatic primary monoamines such as ethylenediamine, diaminopropane (each isomer), diaminobutane (each isomer), diaminopenkune (each isomer), diaminohexane (each isomer); aliphatic primary diamines [;1,
2.3-triaminopropane, triaminohexane (each isomer), triaminononane (each isomer), triaminododecane (each isomer), 1.8-diamino-4-aminomethyloctane, 2,6 -Diamizcapric acid-2-aminoethyl ester, 1,3,6. -) Aliphatic 1 such as riaminohexane, 1,6.11-triaminoundecane, etc.
class triamines; cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, diaminocyclobutane, diaminocyclohexane (each isomer), 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triaminocyclohexane (each isomer) Alicyclic primary monoamines and polyamines such as benzylamine, di(aminomethyl) Hensen (each isomer), aminomethylpyridine (each isomer), di(aminomethyl)pyridine (each isomer), amino These include aromatic aliphatic primary monoamines and polyamines such as methylnaphthalene (all isomers) and di(aminomethyl)naphthalene (all isomers).

In addition, some of the hydrogens in the aliphatic groups, alicyclic groups, and aromatic groups that make up the skeletons of these primary amines are halogens, alkyl groups, alkoxy groups, aryl groups, ester groups, and sulfone atoms. , a cyano group, or the like, or the skeleton may contain an unsaturated bond, an ether bond, an ester bond, a thioether bond, a sulfone bond, a ketone bond, or the like.

The amount of urea used in the present invention is preferably 0.5 mole or more of urea per mole of amino group of the aliphatic primary amine. More preferably, the amount used is 0.5 mole or more of urea per mole of amino group of the aliphatic primary amine. The amount is 8 moles or more and 2 moles or less. If the amount of urea is less than 0.5 mol per mol of amino group of the aliphatic primary amine, complexly substituted urea compounds will be produced as by-products,
If the amount is more than 2 moles, a complexly substituted urea compound may be produced as a by-product or unreacted urea may remain, which is not preferable.

Although it is a preferred practice to use an excess amount of an aromatic hydroxyl compound as a solvent in the practice of this invention, other suitable solvents may also be used.

Such solvents include, for example, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and decane;
Aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; Nitriles such as acetonitrile and benzonitrile; Sulfones such as sulfolane, methylsulfolane, and dimethylsulfone; Tetrahydrofuran, 1.4-dioxane, and 1.2-dimethoxyethane Ethers such as;
Examples include ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate and ethyl benzoate.

Furthermore, halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, fluorobenzene, chlorotoluene, chlornaphthalene, bromonaphthalene; chlorhexane, chlorocyclohexane, trichlorotrifluoroethane, methylene chloride, tetrachloride; Halogenated aliphatic hydrocarbons such as carbon or halogenated alicyclic hydrocarbons are also used as the solvent.

When carrying out the present invention, it is preferable to carry out the reaction at a temperature range of 150 to 280°C. If the reaction is carried out at a temperature lower than 150°C, the aromatic hydroxyl compound and the aliphatic primary amine, ammonia, and urea will strongly bond. Therefore, the reaction is slow, the reaction hardly occurs, or the amount of complexly substituted urea compounds increases, which is not preferable.

If the reaction is carried out at a temperature higher than 280°C, urea may decompose, aromatic hydroxyl compounds may undergo dehydrogenation,
Alternatively, it is not preferable because it may cause a decrease in yield due to decomposition or modification of the aliphatic 0-aryl urethane product.In this sense, the more preferable temperature range is 1.
The temperature is 80-260°C. A more preferable temperature range is 20
The temperature is 0 to 250°C.

When carrying out the present invention, the amount of ammonia that is produced as a by-product in the reaction system will vary somewhat depending on the reaction temperature and the difference in basicity between the primary amine and the aromatic hydroxyl compound.
It is almost constant regardless of the composition of the reaction system, and it is very important to remove the ammonia so that the concentration in the reaction solution is 2% by weight or less. This is because when the ammonia concentration is 2% by weight or more, almost no aliphatic 0-aryl urethane is obtained due to the equilibrium shown in Formula I. Furthermore, in order to increase the yield of aliphatic 〇-aryl urethane, it is preferable to remove the ammonia so that the concentration of ammonia in the reaction liquid becomes 1% by weight or less.More preferably, the ammonia concentration in the reaction liquid is It is 0.5% by weight or less.

One of the preferred embodiments for removing ammonia by-produced in the reaction system is a reactive distillation method. That is, the reactive distillation method is a method in which ammonia, which is successively produced during a reaction, is separated in gaseous form by distillation. In order to increase the efficiency of ammonia distillation, it can also be carried out under boiling of a solvent or an aromatic hydroxyl compound.

Another preferred embodiment for removing ammonia by-produced in the reaction system is a method using an inert gas.

That is, this is a method in which ammonia, which is successively produced during the reaction, is separated from the reaction system by being entrained in a gaseous inert gas. It is also a preferred method to introduce such inert gases, such as nitrogen, helium, argon, carbon dioxide, methane, ethane, propane, etc., singly or in combination into the reaction system. Organic solvents with a similar effect include low-boiling point organic solvents, such as dichloromethane, chloroform, halogenated hydrocarbons such as carbon tetrachloride, lower hydrocarbons such as pentane, hexane, heptane, benzene, toluene, and xylene, and acetone. ,
Monoketones such as methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane can also be used.

Furthermore, a catalyst can also be used for the purpose of lowering the temperature using reactive distillation, inert gas, etc., or increasing the reaction rate. Such catalysts include, for example, elemental rare earth elements, antimony, bismuth and their oxides, sulfides and salts; elemental boron and boron compounds; copper group, zinc group, aluminum group of the periodic table, carbon and oxides and sulfides of these metals; carbides and nitrides of elements of the carbon group, titanium group, vanadium group, and chromium group excluding carbon in the periodic table are preferably used. When using a catalyst, the quantitative ratio of the catalyst and the aliphatic primary amine can be set as desired;
It is preferable to use the catalyst in a weight ratio of usually 0.0001 to 100 times the weight of the grade amine.

Another preferred embodiment for removing ammonia by-produced in the reaction system is a method of separating ammonia by adsorbing it onto an adsorbent. Examples of such adsorbents include silica, alumina, various zeolites, diatomaceous earths, etc.
Adsorbents that can be used under temperature conditions of ~280°C can be used.

Furthermore, in order to remove ammonia by-produced in the reaction system, a combination of a reactive distillation method, a method using an inert gas, a method of separating the ammonia by adsorption onto an adsorbent, etc. can be used.

When carrying out the present invention, the reaction pressure varies depending on the composition of the reaction system, reaction temperature, ammonia removal method, type of reaction apparatus, etc., but it is usually preferable to carry out the reaction in a pressure range of 0.1 to 50 atm. .

More preferably, a pressure range of 1 to 30 atm is preferred for industrial implementation. Similarly, the reaction time also varies depending on the composition of the reaction system, reaction temperature, ammonia removal method, type of reaction equipment, etc. , usually several tens of minutes to several tens of hours. Preferably, it is several tens of minutes to several hours, and the shorter the better.

The style of the apparatus used to carry out the present invention is not limited in any way; for example, the reaction proceeds while the raw material liquid is allowed to flow down inside a vertical tubular apparatus, and ammonia as a by-product is taken out from the upper part of the apparatus. Preferably used are a method in which the ammonia is removed by using a seed mold, a method in which the reaction is carried out using a seed mold device, and ammonia produced as a by-product is taken out and removed in the gas phase, and a method in which these are combined. Furthermore, it is also a preferable method to provide a distillation column and/or a partial condenser, etc. above these devices, if necessary.

Furthermore, the reaction of the present invention can be carried out either batchwise or continuously.

The method of the present invention is suitable for producing aliphatic 0-aryl monourethane and polyurethane, and is a masked isocyanate of 1,6-hexamethylene diisocyanate, which is used in large quantities industrially. , Production of 6-hexamethylene-〇,0°-diphenyl urethane, 3-
3-phenoxycarbonylaminomethyl, a masked isocyanate of methyl incyanato-3,5,5-trimethylcyclohexyl isocyanate (IPI)
This method is also suitable for producing 3,5,5-trimethyl-1-phenoxycarbonylaminocyclohexane and m-xylylene-0,0-diphenylurethane, which is a masked isocyanate of m-xylylene diisocyanate.

(Effect of the invention) According to the present invention, there are the following advantages compared to the conventional method.

l) Aliphatic 0-aryl urethane can be obtained in high yield by performing the reaction while actively removing by-product ammonia from the reaction system so that the ammonia concentration in the reaction solution is 2% by weight or less. can.

2) Since phosgene and carbon monoxide are not used, there are no problems such as corrosion or toxicity, and there is no problem of large amounts of hydrogen chloride gas being produced as by-products. Furthermore, there is no need to use expensive noble metal catalysts, so it is inexpensive.

3) The process is simple because it is a one-stage reaction.

4) Since the urethane yield is high, it is advantageous for industrial implementation.

5) Furthermore, since the obtained urethane is an aliphatic O-aryl urethane, it can be easily thermally dissociated and is advantageous for use as an intermediate raw material for masked isocyanate and aliphatic isocyanate.

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

The amount of ammonia in the reaction solution was determined by extracting the reaction solution with 10 times or more of water to obtain an aqueous solution, and then quantifying ammonium ions using ion chromatography (IC).

The ion chromatography column and detector are manufactured by Tosoh TS.
Using K-gel IC-cation and CM-8000, a 2mM 4 nitric acid aqueous solution was flowed as an eluent at 1.2-min/3.
Measured at 5°C.

Further, the amount of ammonia in the reaction gas was determined by gas chromatography (CC).

Aromatic hydroxyl compounds and aliphatic primary amines were quantified by gas chromatography (GC) and liquid chromatography (LC).

Quantification of urea and aliphatic O-aryl urethanes was performed using gel permeation chromatography (Gpc) and L
I went with C.

Example 1 1 equipped with a thermometer, stirrer, reflux and gas introduction tube
29 g of 1,6-hexamethylene diamine (hereinafter referred to as DA), 33 g of urea, and 470 g of phenol were placed in a four-glass flask with a capacity of 1,000 d, and nitrogen gas was introduced at a rate of 20 ffi per hour from a ball filter that reached the bottom of the reactor.
Under boiling phenol (170-180℃) while flowing.
The reaction was carried out with stirring.

Furthermore, the following operation was repeated every 20 hours.

First, the entire amount of the reaction solution was collected, and the weight (g) was measured. Next, 1.0g was collected and 1°6-hexamethylene-o,o'-diphenylurethane (HDPh) contained in the reaction solution was collected.
) and ammonia (NHi) weight percent were determined. From this value, 1. The molar yield% of 6-hexamethylene-0,0°-diphenyl urethane was calculated.

By 80 hours, 140 g of phenol containing ammonia had flowed out from the upper part of the reflux vessel.

The results are shown in Table 1.0 From Table 1, if ammonia by-produced in the reaction solution is actively removed to 0.01% by weight, 1.6-
Hexamethylene-〇, OI-diphenylurethane is 90
% in high yield. It is also seen that the greater the weight percent of ammonia produced as a by-product in the reaction solution, the lower the yield of 1,6-hexamethylene-〇,0°-diphenylurethane.

Therefore, it has become clear that there is an equilibrium expressed by Formula 1, and that the equilibrium is biased toward the yarn side.

Table 1 Comparative Example 1 The same operation as in Example 1 was performed except that nitrogen gas was not passed. Ammonia was 2.2 times i% in the reaction solution stirred for 80 hours at reflux temperature (179-182"C).
Although it contained, 1,6-hexamethylene-〇, O°-
Diphenylurethane was not detected. Moreover, there was no effluent from the upper part of the reflux vessel.

When phenol was removed from the reaction solution after 80 hours,
43 g of a tan solid was obtained.

Therefore, 1.6-hexamethylene-0,0''-diphenylurethane was extracted with dimethylacetamide, which is a good solvent, and further analyzed.However, from this extract, 1.
No 6-hexamethylene-o,o'-diphenylurethane was detected.

Comparative Example 2 The same operation as in Comparative Example 1 was performed without flowing nitrogen gas, except that 650 g of n-octatool, which is a type of alcohol, was used instead of phenol.

When n-octatool was distilled off from the O reaction solution that was stirred at reflux temperature (180 to 182°C) for 20 hours, 100 g of a pale yellow reaction product was obtained.

In this, 87 g of hexamethylene di(n-octyl urethane) was produced. 1.6-hexamethylene-0,0”-di(n-octylurethane) per HDA charged
The yield was 81%.

The following was found from Example 1 and Comparative Example 1. In the reaction for producing aliphatic O-aryl urethane from an aromatic hydroxyl compound, urea, and aliphatic primary amine, ammonia is extremely difficult to remove.

Therefore, unless ammonia is efficiently removed, the desired aliphatic 0-aryl urethane cannot be obtained.

In this case, it has been found that methods such as reactive distillation and methods using inert gas are extremely effective in removing ammonia.

Further, from Comparative Examples 1 and 2, ammonia can be easily removed in the reaction for producing aliphatic O-alkylurethane from alcohol, urea, and aliphatic primary amine. Therefore, the fact that ammonia is extremely difficult to remove in the reaction for producing aliphatic O-aryl urethanes mentioned above is due to the fact that ammonia
-It was found that something completely unexpected from the reaction for producing alkyl urethanes was observed.

Examples 2 to 10 Raw material liquid A was continuously flowed from the upper part of a vertical reaction tube 1 with a volume of 21 filled with filler shown in FIG. 1, and reaction liquid B was continuously recovered from the lower part of the reaction tube 1. did.

On the other hand, nitrogen gas C is introduced from the bottom of the reaction tube 1, and the reaction gas E is passed through the cooling reflux device 2 and gas-liquid separator 3 at the top of the reaction tube.
was recovered. At this time, condensed components accompanying the gas were continuously collected from the lower part of the gas-liquid separator.

464 g HDA, 504 g urea, and 7 phenols
．． A raw material liquid consisting of 520 g was used, the reaction pressure was 6 atm (2 atm in Examples 9 and 10), and the temperature of the cooling refluxer 2 was 1.
40°C1 nitrogen gas amount is 20j/hour in standard B conversion! It flowed. Reaction temperature (°C) and inflow of raw material liquid A! (g/H
r) was conducted under various conditions shown in Table 2. The average residence time was 5 to 30 minutes.0 After the reaction was completed, the entire amount of the reaction>&B was collected and the heavy! (g) was measured.

Next, 1,6-hexamethylene-〇 contained in reaction solution B,
0°-diphenylurethane (HDPh) and ammonia (NHs) weight percent were placed. From this value, 1.6-hexamethylene-o, o' per mole of HDA charged
- The molar yield % of diphenyl urethane was calculated. The results are shown in Table 2.

Table 2 From the results of Example 2, it was found that the amount of ammonia by-produced in the reaction solution was 0.
．． It was found that 1,6-hexamethylene-〇, O1-diphenyl urethane could be continuously obtained at a high yield of 92% by actively removing up to 0.01% by weight.

Moreover, from the results of Examples 2 to 6, the more ammonia by-produced in the reaction solution was removed, the more 1,6-hexamethylene-0,
High yield of 0°-diphenyl urethane, and 1.
In order to obtain 6-hexamethylene-〇,0゛-diphenyl urethane, the ammonia concentration as a by-product in the reaction solution should be reduced to 2.
% by weight, further 20%
In order to obtain the above 1.6-hexamethylene-〇IO°-diphenylurethane yield, it is preferable to remove the ammonia concentration as a by-product in the reaction solution to 1% by weight.
It has been found that in order to obtain a higher yield, it is preferable to remove the ammonia concentration in the liquid to 0.5% by weight.

Furthermore, from a comparison of Example 2 and Examples 7 to 10, 1.6
In order to obtain -hexamethylene-〇,0°-diphenyl urethane, the reaction temperature is preferably in the range of 150°C to 280°C, and in order to obtain a higher yield,
Example 11 It was found that it was preferable for the reaction temperature to be in the range of 180° C. to 260° C. The same operation as in Example 2 was performed with the composition of raw material A changed as follows. HDA 464 g, urea 504 g1 and m
- A raw material liquid consisting of 8,640 g of cresol was used, the reaction pressure was 6 atm, the reaction temperature was 220°C, the inflow rate of raw material liquid A was 100 g per hour, and the amount of nitrogen gas was 20ffi per hour in terms of standard conditions. 0 Reaction completed. After that, reaction solution B was 8,880
g was recovered.

In this, 1,6-hexamethylene-o,o'-di(m
-cresyl urethane) was contained in an amount of 15.9% by weight, and ammonia was contained in an amount of 0.01% by weight. From this value, 1.6-hexamethylene-0,0' per mole of HDA charged
-Di(m-cresyl urethane) yield was 93%.

Example 12 The same operation as in Example 11 was carried out under the same reaction conditions, but with the composition of raw material A changed as follows. That is, HDA464g
, 504g of urea, and 504g of urea.

A raw material liquid consisting of 10.280 g of phenol was used.

After the reaction was completed, 9,625 g of reaction solution B was recovered. Among these are 1. 6-hexamethylene-0,0"-di(O-chlorophenyl urethane) was contained in 13.5% by weight, and ammonia was contained in 0.01f!1%. From this value, HD
1°6-hexamethylene-o per mole of A charged,
o'-di(O-chlorophenyl urethane) yield is 91
%Met.

Example 13 The same operation as in Example 11 was carried out under the same reaction conditions, but with the composition of raw material A changed as follows. That is, HDAJ64
g, 504 g of urea, and 11,52 g of 2-naphthol.
A raw material liquid containing 0 g was used.

After the reaction was completed, 11,457 g of reaction solution B was recovered. In this, 1,6-hexamethylene-o,o'-di(2-
Naphthyl urethane) was contained in an amount of 14.0% by weight, and ammonia was contained in an amount of 0.01% by weight.

From this value, the yield of 1.6-hexamethylene-OIθ'-di(2-naphthylurethane) per mole of HDA charged was 89%.

Example 14 The same operation as in Example 11 was carried out under the same reaction conditions, but with the composition of raw material A changed as follows. That is, 3-aminomethyl-3,5,5-trimethylcyclohexylamine (I
PA) 680g, urea 504g1 and phenol7.
A raw material liquid consisting of 520 g was used.

After the reaction was completed, 7,931 g of reaction solution B was recovered. Among these, 3-phenoxycarbonylaminomethyl-3,5,
5-trimethyl-1-phenoxycarbonylaminocyclohexane was 18.2% by weight, and ammonia was 0.0%.
It contained 1% by weight. From this value, 3-phenoxycarbonylaminomethyl-3 per mole of IPA charged,
The yield of 5,5-trimethyl-1-phenoxycarbonylaminocyclohexane was 89%.

Example 15 The same operation as in Example 11 was carried out under the same reaction conditions, but with the composition of raw material A changed as follows. That is, a raw material liquid consisting of 544 g of m-xylylene diamine, 504 g of urea, and 7.520 g of phenol was used.

After the reaction was completed, 7,690 g of reaction solution B was recovered. This contained 18.8% by weight of m-xylylene-o,o'-diphenylurethane and 1% by weight of 0°O ammonia. From this value, the yield of m-xylylene-0,0''-diphenylurethane per mole of m-xylylene diamine charged was 96%.

Example 16 The same operation was carried out under the same reaction conditions as in Example 11 except that the amount of nitrogen gas was flowed at 101 per hour in terms of standard conditions, but the composition of raw material A was changed as follows. That is, 516 g of n-octylamine, 257 g of urea, and 3 g of phenol.
A raw material liquid consisting of 760 g was used.

After the reaction was completed, 1.029 g of reaction solution B was recovered. This contained 30.4% by weight of n-octyl-〇-phenyl urethane and 0.01% by weight of ammonia.

From this value, n per mole of n-octylamine charged
-Octyl-〇-phenyl urethane yield was 97%.

Example 17 The same operation as in Example 16 was carried out under the same reaction conditions, but with the composition of raw material A changed as follows. That is, a raw material solution consisting of 516 g of n-octylamine, 257 g of urea, and 3720 g of 4.4°-dihydroxybiphenyl was used.

After the reaction was completed, 4353 g of reaction solution B was recovered.

This contained 21.8% by weight of 4,4'-di(n-octylcarbamoyloxy)-biphenyl and 0.01% by weight of ammonia. From this value, the yield of 4.4'-di(n-octylcarbamoyloxy)-biphenyl per mole of n-octylamine charged was 48%.

Example 18 The same operation as in Example 2 was carried out using a vertical reaction tube 1 filled with a filler and having a volume of 81, changing the composition of raw material A and the reaction conditions as follows. HDA464g1 urea504g,
Using a raw material liquid consisting of 15,040 g of phenol, the reaction pressure was 4.2 atm, the reaction temperature was 235° C., the temperature of the cooling refluxer 2 was 100° C., and the flow rate of the raw material liquid A was 1.2 atm/hour.
500g, and the amount of nitrogen gas is 10% per hour in standard conditions.
01 was played. Average residence time was 30 minutes.

After the reaction was completed, 15.119 g of reaction solution B was recovered. Among these are 1. 6-hexamethylene-o,o'-diphenylurethane was 9.23% by weight, and ammonia was 0.9% by weight.
It contained 0.4% by weight. From this value, the yield of 1.6-hexamethylene-o,o'-diphenylurethane per mole of HDA charged was 98%.

In addition, by the end of the reaction, the reaction gas EN is 1 in terms of standard conditions.
, 435ffi were recovered, and GC analysis showed that 25% by volume of ammonia gas was contained in the reaction gas, which means that 99% of the theoretical amount of ammonia was recovered as a gas.

Furthermore, phenol was distilled off from reaction solution B using a rotary evaporator to obtain 1.560 g of pale yellow solid.Next, this solid was dissolved in xylene 31 at 100°C and recrystallized. .350 g of white solid was obtained. The purity of 1,6-hexamethylene-0,0'-diphenyl urethane was 99% by weight by CPC analysis.

Example 19 The same procedure as in Example 18 was carried out except that n-hexane was used instead of nitrogen gas.

385 g of n-hexane per hour was introduced with a gas rod into the lower part of the vertical reaction tube 1 via an evaporator.

After the reaction was completed, 15.213 g of reaction solution B was recovered. In this, 1,6-hexamethylene-o,o'-diphenyl urethane is 9.08% by weight, and ammonia is 0.00% by weight.
It contained 4% by weight. From this value, the yield of 1.6-hexamethylene-〇,0°-diphenylurethane per mole of HDA charged was 97%.

Further, phenol was distilled off using a rotary evaporator, and then recrystallized from xylene of t o ``c, 32'' to obtain 1,336 g of white solid.1.
The purity of 6-hexamethylene-〇,o''-diphenylurethane was found to be 99% by weight by GPc analysis.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram of Examples 2 to 19. (1 other person)

Claims (1)

[Claims] A method for producing an aliphatic 0-aryl urethane from an aliphatic primary amine, comprising: a) reacting the aliphatic primary amine with an aromatic hydroxyl compound and urea; b) ammonia in the reaction solution. 1. A method for producing an aliphatic 0-aryl urethane, comprising: performing the reaction while removing by-product ammonia from the reaction system so that the concentration is 2% by weight or less.