JPS6320221B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing polymethylene polyphenyl polycarbamate. More specifically, the present invention relates to a method for producing polymethylene polyphenyl polycarbamate, which comprises heating bis(N-carbalkoxyanilino)methane in the presence of an acid catalyst. Polymethylene polyphenyl polycarbamate is a substance useful as a raw material for agricultural medicines, polyamides, polyurethanes, etc. Further, since polymethylene polyphenyl polycarbamate can be thermally decomposed to produce the corresponding polymethylene polyphenyl polyisocyanate, it is desired to develop an industrially advantageous production method. A known method for producing polymethylene polyphenyl polycarbamate is to react the corresponding polymethylene polyphenyl polyisocyanate with alcohol, but this method is toxic to the production of the raw material polymethylene polyphenyl isocyanate. Strong aniline and phosgene must be used, and the manufacturing method is complicated. In addition, as another method for producing polymethylene polyphenyl polycarbamate, a method is known in which the corresponding polymethylene polyphenyl polyamine is reacted with an alkyl chloroformate; All acid alkyl esters are highly addictive or irritating and difficult to handle.
The manufacturing method is also complicated and cannot be called an industrial manufacturing method. Furthermore, as another method for producing polymethylene polyphenyl polycarbamate, a method in which N-phenyl carbamate and formaldehyde are reacted is known. For example, in West German Patent No. 1042891, a condensation product is obtained by heating N-phenylethyl carbamate and formaldehyde with an aqueous hydrochloric acid solution at 95 to 100°C for 20 hours. The main component is enyl polycarbamate. However, in the method described in German Patent No. 1042891, the reaction is very slow, and even if the reaction is carried out for a long time, a large amount of unreacted raw materials remain. In contrast to these known methods, the method of the present invention is a new method for producing polymethylene polyphenyl polycarbamate characterized by heating bis(N-carbalkoxyanilino)methane in the presence of an acid catalyst. The objective is to provide a method for producing high quality polymethylene polyphenyl polycarbamate with good yield. Another object is to provide an industrially advantageous production method using a reaction method that is simpler than conventional known methods. That is, the method of the present invention is based on the general formula () (In the formula, R ₁ is a lower alkyl or cycloalkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, R ₂ is a hydrogen atom, a halogen atom,
bis(N-carbalkoxyanilino), which represents a lower alkyl or alkoxy group having 1 to 6 carbon atoms, and n is a positive integer of 1 to 4;
By heating methane in the presence of an acid catalyst, the general formula () (In the formula, R ₁ , R ₂ and n have the same meanings as in the general formula (), and m is 0 or a positive integer from 1 to 5.) be. The bis(N-carbalkoxyanilino)methane used in the method of the present invention is represented by the general formula (), and for example, in the general formula (), R ₁ is methyl, ethyl, n-propyl, iso ―
Alkyl groups such as propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, pentyl groups derived from n-pentane and its isomers, hexyl groups derived from n-hexane and its isomers, or a cycloalkyl group such as cyclopentane or cyclohexane, or an aryl group such as phenyl or naphthyl, which is unsubstituted or has an alkyl group such as methyl or ethyl, or a substituent such as a halogen atom, and R ₂ is a hydrogen atom, chlorine,
Halogen atoms such as bromine and fluorine, or methyl, ethyl, n-propyl, iso-propyl, n
Alkyl groups such as -butyl, sec-butyl, iso-butyl, tert-butyl, pentyl group derived from n-pentane and its isomers, hexyl group derived from n-hexane and its isomers, or these alkyl groups It is bis(N-carboalkoxyanilino)methane, which is an alkoxy group whose constituent components are bis(N-carboalkoxyanilino)methane. For example, in the general formula (), R ₁ is the above-mentioned alkyl group and R ₂ is a hydrogen atom, such as bis(N-carboalkoxyanilino)methanes, R ₁ is the above-mentioned alkyl group, and R bis(N-carbalkoxyhaloanilino)methanes in which ₂ is the aforementioned halogen atom; bis(N-carbalkoxyalkylanilino)methanes in which R ₁ and R ₂ are the aforementioned alkyl groups; Bis(N-carbalkoxyalkoxyanilino)methanes where R ₁ is the above-mentioned alkyl group and R ₂ is the above-mentioned alkoxy group, R ₁ is a cyclopentyl or cyclohexyl group and R ₂ is a hydrogen atom bis(N-cycloalkoxyanilino)methanes such as R ₁ is a cyclopentyl or cyclohexyl group and R ₂ is the aforementioned halogen atom, R ₁ is a cyclopentyl or cyclohexyl group, and _{R 2} is _an alkyl group; bis(N-cycloalkoxyalkoxyanilino)methanes or bis(s) in which R ₁ is unsubstituted or a lower alkyl group such as methyl, ethyl, propyl, or butyl group, or a phenyl group or naphthyl group substituted with a halogen atom. (N-carboaryloxyanilino)methane is mentioned. Preferably bis(N-carbomethoxyanilino)methane, bis(N-carboethoxyanilino)methane, bis(N-carbo-n-propoxyanilino)methane, bis(N-carboisopropoxyanilino)methane, Bis(N-carbo-n-
butoxyanilino)methane, bis(N-carbo-
sec-butoxyanilino)methane, bis(N-carbo-isobutoxyanilino)methane, bis(N
-carbo-tert-butoxyanilino)methane, bis(N-carbobomethoxy-o-chloroanilino)methane, bis(N-carboethoxy-o-chloroanilino)methane, bis(N-carbomethoxy-o-methylanilino)methane , bis(N-carbocyclohexylohexyanilino)methane, bis(N-carbophenoxyanilino)methane, and the like. These bis(N-carbalkoxyanilino)methanes can be synthesized by reacting the corresponding bis(N-anilino)methane with an alkyl chloroformate. In addition, under specific conditions, N-phenyl carbamate and formaldehyde
For example, it can be synthesized by a low temperature reaction in the presence of an acid catalyst. Generally, the latter method is preferred because the reaction is slow and the yield is very low. The acid catalyst used in the method of the present invention is hydrochloric acid,
Mineral acids such as sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid,
Examples include organic acids such as acetic acid, oxalic acid, and toluenesulfonic acid. Also effective are acids called superacids such as hydrobromic acid, perchloric acid, chlorosulfonic acid, and trichloromethanesulfonic acid. Also effective are ion exchange resins having acidic groups such as carboxyl groups and sulfonic acid groups, and acids called Lewis acids, such as boron trifluoride, iron chloride, aluminum chloride, zinc chloride, and titanium chloride. The acid acts as a catalyst in this reaction. The amount of acid to be used is only a small amount necessary to substantially catalyze the reaction, and there is no particular restriction, but if no acid is used at all, the desired reaction will not substantially occur. When using a protic acid such as sulfuric acid or hydrochloric acid as an aqueous solution, it is preferable to use it at a concentration of 10% by weight or more as an aqueous solution or at a molar ratio of 0.01 or more to the raw material bis(N-carbalkoxyanilino)methane, but trifluoromethane When using a super strong acid such as sulfonic acid or a Lewis acid such as boron trifluoride or its compound, a smaller amount than the above-mentioned amount, for example 0.0001 to 0.01 molar ratio, is effective. The used acid is generally separated and recovered from the product by separation operations such as liquid separation, extraction, distillation, or filtration after the reaction, and can be reused repeatedly. The method of the present invention is generally carried out by heating bis(N-carbalkoxyanilino)methane as a raw material together with an acid catalyst in the absence of a solvent or in the presence of a suitable solvent. Examples of solvents used as necessary include aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and their alkyls. , halogen and nitro substituted substances, halogenated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, fatty acid alkyl esters such as ethyl acetate, diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran Examples include ethers such as The reaction temperature is generally 10-150°C, preferably
The temperature is 20-120℃. If the temperature is too high, undesirable side reactions such as hydrolysis reactions occur. The reaction time varies depending on the reaction conditions, but in the case of a batch reaction, 5
Minutes to 10 hours. The method of the present invention can be carried out either by a batch reaction method in which the raw materials and acid catalyst are charged all at once and reacted, or by a continuous method in which the raw materials and acid catalyst are continuously supplied together or separately and the product is continuously taken out. can. The method of the present invention is usually carried out at normal pressure, but can also be carried out under reduced pressure or increased pressure, if necessary. According to the method of the present invention, a methylene-crosslinked polyphenyl polycarbamate represented by the above-mentioned general formula () can be obtained depending on the bis(N-carbalkoxyanilino)methane used as a raw material. Under normal reaction conditions, a mixture is obtained in the general formula () in which the main component is a dinuclear substance with m=0 and a smaller amount of a polynuclear substance with m=1 or more. Most of the dinuclear forms are 4,4'-isomers, and other isomers are usually absent or contained in small amounts. After the acid catalyst is separated from the reaction product containing the desired product after the reaction, if necessary, the desired product is obtained as it is or through operations such as washing with water and drying. Furthermore, if the product contains impurities or unreacted raw materials, they can be removed and purified by distillation, recrystallization, extraction, etc., as necessary, to obtain a product of higher quality. According to the method of the present invention, polymethylene polyphenyl polycarbamate can be produced by a simpler reaction method than conventionally known methods. Furthermore, the reaction conditions are mild and the desired product can be obtained in a short time. The method of the present invention will be explained below with reference to Examples. Example 1 In a 50 ml flask equipped with a thermometer and a stirrer, 3.4 g of bis(N-carboethoxyanilino)methane and
50% sulfuric acid aqueous solution 10g, 1,2-dichloroethane 5
ml and stirred at 80℃ for 3 hours. The mixture was cooled and separated to obtain 3.4 g of an organic phase. A portion of it was dissolved in tetrahydrofuran and analyzed by liquid chromatography using naphthalene as an internal standard. The composition (wt%) of the product was 3% unreacted, 10% N-phenylethyl carbamate, and R in the general formula (). ₁
is an ethyl group, R ₂ is a hydrogen atom, and bis(N-carboethoxyaminophenyl)methane (dinuclear) where m = 0 is 77%, and trinuclear with m = 1 is 3%. The rest were polynuclear bodies with m=2 or more. This result means that the reaction rate of bis(N-carboethoxyanilino)methane is 97% and the yield (selectivity) of polymethylene polyphenyl polycarbamate (m = 0 to 5) is 82% or more based on the consumed raw material. . Similar results were obtained when 1,2-dichloroethane was not used. Examples 2 to 8 Instead of bis(N-carboethoxyanilino)methane, bis(N-carboalkoxyanilino)methanes shown in the raw material column of Table 1 were used, and the reaction was otherwise carried out in the same manner as in Example 1. . The results are shown in Table 1.

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【table】

Claims (1)

[Claims] 1 General formula () (In the formula, R ₁ is a lower alkyl or cycloalkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, R ₂ is a hydrogen atom, a halogen atom,
bis(N-carbalkoxyanilino), which represents a lower alkyl or alkoxy group having 1 to 6 carbon atoms, and n is a positive integer of 1 to 4;
General formula (), characterized by heating methane in the presence of an acid catalyst (In the formula, R ₁ , R ₂ and n have the same meanings as in the general formula (), and m represents 0 or a positive integer from 1 to 5). Method for producing polymethylene polyphenyl polycarbamate .