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A kind of preparation method of methyl phenylcarbamate

A technology of methyl phenylcarbamate and diphenylurea, which is applied in the field of organic chemical industry, can solve the problems of low synthesis efficiency of methyl phenylcarbamate and complicated product separation, and achieve increased production capacity per unit time, high separation degree, and shortened reaction the effect of time

Active Publication Date: 2018-09-04
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention provides a method for preparing methyl anilate, especially a reaction separation method for preparing high-purity methyl anilate through non-catalysis, which solves the problem of low synthesis efficiency and complicated product separation of methyl anilate at present and other problems, obtained high-purity methyl phenylcarbamate that can be used in practical applications

Method used

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  • A kind of preparation method of methyl phenylcarbamate
  • A kind of preparation method of methyl phenylcarbamate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Continuously input urea and aniline into the pre-reactor 7 at a feed rate of 0.34 kg / h and 5.3 kg / h respectively, and keep it at 140° C. for 0.5 hour under agitation, and the mixed solution of the pre-reactor enters into the synthesis two through the overflow port. In the phenylurea reactor 9, the temperature is kept at 160° C. for 3 hours under a slight negative pressure of 90 kPa. The gas generated by the reaction enters the ammonia gas separation tower 8 after being condensed from the top of the kettle, and the condensed liquid aniline is recycled and reused. The reaction solution enters the falling film evaporator 11 through the regulating valve, aniline is evaporated from the top, and diphenylurea is further purified through the evaporation crystallizer, and then enters the mixing tank 15 with stirring through the discharge valve 14 as solid feed, and is massaged with methanol The feed ratio of 1:10 is stirred and mixed to form a slurry material, and then injected i...

Embodiment 2

[0046] The urea and aniline are continuously input into the pre-reactor 7 at the feed rate of 0.68kg / h and 4.2kg / h respectively, and kept at 160°C for 0.1 hour under agitation, and the mixed liquid of the pre-reactor enters into the synthesis two through the overflow port. In the phenylurea reactor 9, the temperature is kept at 180° C. for 2 hours under a slight negative pressure of 92 kPa. The gas generated by the reaction enters the ammonia gas separation tower 8 after being condensed from the top of the kettle, and the condensed liquid aniline is recycled and reused. The reaction solution enters the falling film evaporator 11 through the regulating valve, aniline is evaporated from the top, and diphenylurea is further purified through the evaporation crystallizer, and then enters the mixing tank 15 with stirring through the discharge valve 14 as solid feed, and is massaged with methanol The feed ratio of mole ratio is 1:15, which is stirred and mixed into a slurry material, ...

Embodiment 3

[0049] Continuously input urea and aniline into the pre-reactor 7 at a feed rate of 1.2kg / h and 11.2kg / h respectively, keep it at 120°C for 1 hour under stirring, and the mixed solution of the pre-reactor enters into the synthesis two through the overflow port. In the phenylurea reactor 9, the temperature is kept at 170° C. for 3 hours under a slight negative pressure of 100 kPa. The gas generated by the reaction enters the ammonia gas separation tower 8 after being condensed from the top of the kettle, and the condensed liquid aniline is recycled and reused. The reaction solution enters the falling film evaporator 11 through the regulating valve, aniline is evaporated from the top, and diphenylurea is further purified through the evaporation crystallizer, and then enters the mixing tank 15 with stirring through the discharge valve 14 as solid feed, and is massaged with methanol The feed ratio of 1:20 is stirred and mixed to form a slurry material, and then injected into the fi...

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Abstract

The invention relates to a preparation method of methylphenylcarbamate. The preparation method comprises 1, adding urea and aniline into a pre-reactor and a diphenyl urea synthesis reactor and synthesizing diphenyl urea, 2, conveying the reaction liquid into a falling film evaporator and an evaporating crystallizer through a feeding pump, separating aniline, mixing the aniline and methanol, feeding the mixture into an alcoholysis reactor, carrying out a reaction process, feeding the reaction materials into a flash evaporation pot, separating a part of methanol and aniline and separating residual methanol and most of aniline through the falling film evaporator to obtain a methylphenylcarbamate crude product, and 3, feeding the methylphenylcarbamate crude product into a scraped film type molecule distillation device and further separating the residual microscale aniline and high-boiling residues so that high purity methylphenylcarbamate is obtained and has purity greater than or equal to 99.9%. The preparation method effectively improves methylphenylcarbamate synthesis efficiency and has a product yield greater than or equal to 98.0%. The preparation method is simple and easy and provides an effective synthesis and separation method of a phenyl carbamate intermediate used in preparation of diphenylmethane diisocyanate through the non-phosgene way.

Description

technical field [0001] The invention relates to the technical field of organic chemical industry, in particular to a method for preparing methyl phenylcarbamate, in particular to a reaction separation method for synthesizing high-purity methyl phenylcarbamate through two-step non-catalytic reactions of urea, aniline and methanol. Background technique [0002] Methyl phenylcarbamate is an important intermediate for the production of diphenylmethane diisocyanate by non-phosgene routes. Solution etc. Among them, the route of synthesizing diphenylurea by urea and aniline, and then synthesizing phenylcarbamic acid with methanol has the advantages of low raw material cost and safe production process, showing a good application prospect. Theoretically, the ammonia by-produced by this method can be recycled and reused to produce raw material urea. In addition, the coupling of methyl phenylcarbamate to prepare diphenylmethane dicarbamate requires high-purity raw materials, otherwis...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C271/28C07C269/04
Inventor 李会泉王利国曹妍李凤姣陈家强贺鹏
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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