Method for auxiliary synthesis of 4,4'-diphenyl methane diamino acid methyl ester by microwave

A technology of methyl dicarbamate and diphenylmethane, which is applied in the field of ester synthesis, can solve the problems of long process reaction time, etc., and achieve the effects of simplifying the post-processing process, reducing production costs, and high catalytic efficiency

Inactive Publication Date: 2010-07-28
HARBIN UNIV OF SCI & TECH
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  • Abstract
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  • Claims
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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to solve the problem that the process reaction time of 4'-methyl diphenylmethane dicarbamate is long and can only be produced by batch operation in order to solve the problem that dimethyl carbonate is used to prepare, and a method is provided. A kind of microwave-assisted synthesis method of 4,4'-diphenylmethane dicarbamate methyl ester

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  • Method for auxiliary synthesis of 4,4'-diphenyl methane diamino acid methyl ester by microwave

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specific Embodiment approach 1

[0009] Specific embodiment 1: In this embodiment, the microwave-assisted synthesis of methyl 4,4'-diphenylmethane dicarbamate has the following steps: 1. Combine 4,4'-diaminodiphenylmethane and carbonic acid in a microwave reactor. The methyl ester is mixed in a weight ratio of 1:5-20, and then ZS-6 catalyst is added to obtain a mixture; 2. The mixture obtained in step 1 is placed in a microwave reactor with a power of 60W~250W and a temperature of 150℃~200℃ React for 0.5-10 minutes, then cool to room temperature, filter, separate, and recrystallize to obtain methyl 4,4'-diphenylmethane dicarbamate; wherein the amount of ZS-6 catalyst added in step 1 is 4,4 '-Diaminodiphenylmethane 0.1% to 5% of the mass; the ZS-6 catalyst described in step 1 is composed of 50% to 80% zinc acetate, 10% to 40% zinc isooctyl dimercaptoacetate and 5 %~10% triethylbenzylammonium bromide composition.

[0010] In this embodiment, the conversion rate of 4,4'-diaminodiphenylmethane can reach 89.3%-99.6%...

specific Embodiment approach 2

[0011] Embodiment 2: The difference between this embodiment and the first embodiment is that the particle size of the ZS-6 catalyst in step one is 80 mesh to 100 mesh. Others are the same as the first embodiment.

[0012] In this embodiment, the conversion rate of 4,4'-diaminodiphenylmethane can reach 89.3%-99.6%, and the yield of methyl 4,4'-diphenylmethanedicarbamate can reach 94.7%-98.1%.

specific Embodiment approach 3

[0013] Specific embodiment three: This embodiment is different from specific embodiment one or two in that the weight ratio of 4,4'-diaminodiphenylmethane to dimethyl carbonate in step one is 1:10. Others are the same as the first or second embodiment.

[0014] In this embodiment, the conversion rate of 4,4'-diaminodiphenylmethane can reach 89.3%-99.6%, and the yield of methyl 4,4'-diphenylmethanedicarbamate can reach 94.7%-98.1%.

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Abstract

The invention provides a method for auxiliary synthesis of 4,4'-diphenyl methane diamino acid methyl ester by microwave, and relates to an ester synthesis method. The invention aims to solve the problems of long process reaction time and single intermittent operation production mode in the conventional method for preparing the 4,4'-diphenyl methane diamino acid methyl ester by using methyl carbonate. The method of the invention comprises the following steps of: mixing 4,4'-diaminodiphenyl methane and methyl carbonate in a microwave reactor, adding a ZS-6 catalyst, performing a reaction of theraw materials under a power of the microwave reactor of 60 to 250W and at the temperature of between 150 and 200 DEG C, cooling the product of the reaction to room temperature, and then performing filtration, separation and recrystallization to obtain the 4,4'-diphenyl methane diamino acid methyl ester. The method has the advantages of short reaction time and the suitability for continuous industrialized production; and the conversion rate of the 4,4'-diaminodiphenyl methane reaches 99.6 percent, and the 4,4'-diphenyl methane diamino acid methyl ester yield reaches 98.1 percent.

Description

Technical field [0001] The invention relates to a method for synthesizing esters. Background technique [0002] 4,4'-Diphenylmethane dicarbamate (English name Methylene diphenyl dicarbamate) is an important intermediate for the synthesis of diphenylmethane diisocyanate. The synthetic methods of methyl 4,4'-diphenylmethane dicarbamate reported in the literature mainly include carbonylation method, urea method, transesterification method and dimethyl carbonate amine hydrolysis method. In the process of preparing 4,4'-diaminodiphenylmethane by the carbonylation method, the oxidative carbonylation requires noble metals as a catalyst, and the production cost is relatively high. At the same time, the use of CO has serious safety problems. The urea process uses phenylurea as a raw material to prepare phenylcarbamate through formaldehyde condensation and methanol alcoholysis. This process avoids the safety problems caused by the use of precious metal catalysts and the use of CO, and the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C271/28C07C269/04
Inventor 刘波由君王毅张辉
Owner HARBIN UNIV OF SCI & TECH
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