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Method for separating and purifying crude product phenyl carbamate

A technology for the separation and purification of phenylcarbamate, applied in the field of separation and purification of phenylcarbamate, can solve the problems of increased production cost, low efficiency, high energy consumption, etc., and achieve reduced energy consumption and production cost, high efficiency, and high energy consumption. The effect of low consumption

Inactive Publication Date: 2010-04-14
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, only using a single extraction or recrystallization method to separate and purify the crude product often requires repeated separation processes, resulting in low efficiency, high energy consumption, and increased production costs.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The acquisition of crude product methyl phenylcarbamate: 0.2 moles of N, N'-diphenylurea, 2 moles of dimethyl carbonate, 0.85 grams of PbO 2% of N, N'-diphenyl weight, added to high pressure In the reaction kettle, replace the air in the kettle with nitrogen, then seal the autoclave, raise the temperature to 160°C under magnetic stirring, react for 1.0 hour, and cool down to room temperature after the reaction, take out the reaction solution and filter to obtain the filtrate, and distill the filtrate under reduced pressure , steam light component dimethyl carbonate, obtain light yellow liquid, after cooling, obtain light gray solid crude product 57.5 grams, the purity of crude product methyl phenylcarbamate is 97.1%.

[0022] The crude product phenylcarbamate prepared by the above-mentioned clean synthesis method is separated and purified by extraction and crystallization coupling process. and cyclohexane, the ratio of water to cyclohexane mass is 1:10), the crude produ...

Embodiment 2

[0024] The acquisition of crude product methyl phenylcarbamate is the same as in Example 1.

[0025] The crude product methyl phenylcarbamate prepared by the above-mentioned clean synthesis method is separated and purified by extraction and crystallization coupling technology, and the specific steps are as follows: get 10.0 grams of crude product methyl phenylcarbamate, and 125 grams of compounded solvents (compounded The solvent is mixed with hydrochloric acid solution and n-heptane of 5% by mass percent concentration, and the mass ratio of the two is 1: 10), and the thick product methyl phenylcarbamate is stirred and dissolved in the compounded solvent, and the dissolution temperature is 60 ℃, then stand at constant temperature for phase separation, separate the lower layer solution containing impurities, cool the solution containing methyl phenylcarbamate in the upper layer, and separate crystallization, the crystallization temperature is 15°C, filter and wash after crystall...

Embodiment 3

[0027] The acquisition of crude product methyl phenylcarbamate is the same as in Example 1.

[0028] The crude product phenylcarbamate prepared by the above-mentioned clean synthesis method is separated and purified by extraction and crystallization coupling process, and the specific steps are as follows: get 10.0 grams of crude product methyl phenylcarbamate, and 200 grams of compounded solvents (compounded The solvent is compounded by mass percent concentration of 5% dilute sulfuric acid and chlorobenzene, the mass ratio of the two is 1: 20), the thick product methyl phenylcarbamate is stirred and dissolved in the compounded solvent, and the dissolution temperature is 90°C, then stand at constant temperature for phase separation, separate the lower layer solution containing impurities, cool the upper layer solution containing methyl phenylcarbamate, and separate crystallization, the crystallization temperature is 30°C, filter and wash after crystallization to obtain phenylcar...

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Abstract

The invention discloses a method for separating and purifying crude product phenyl carbamate in the technical field of phenyl carbamate separation and purification, which comprises separating and purifying crude product phenyl carbamate through utilizing the extractive crystallization coupling process, stirring and dissolving the crude product phenyl carbamate in compound solution with dissolvingtemperature of 40-90 DEG C, then placing statically to separate, separating lower solution with foreign matters, cooling upper solution which contains phenyl carbamate, and crystallizing to separate with crystallization temperature of 5-30 DEG C, finally filtering and washing after crystallizing, thereby obtaining the phenyl carbamate with purity over 99.5%. The invention can carry out the extraction and separation on the same device, and simplifies a separating device, the compounded extraction crystallization composite solution has high efficiency with less quantity, phenyl carbamate with purity over 99.5% without variegated color can be obtained through separating and purifying crude product for one time, and the method has simple process, low energy consumption, low cost and high efficiency.

Description

technical field [0001] The invention belongs to the technical field of separation and purification of phenylcarbamate, in particular to a method for separating and purifying a crude product of phenylcarbamate. Background technique [0002] Phenyl carbamate is a key intermediate in the process of non-phosgene synthesis of isocyanate. In the traditional isocyanate synthesis industry, phosgene synthesis is mostly used. With the increasing environmental protection requirements, the development of non-phosgene synthesis methods has become a very important topic in the chemical industry. Among them, the non-phosgene synthesis process of phenylcarbamate has become a research hotspot. [0003] US4876379 has announced to take aniline, methyl alcohol and carbon monoxide as raw material, with air, oxygen or other compounds as oxidant, the aniline oxidative carbonylation method of catalyzer synthetic methyl phenylcarbamate with the chloride of palladium or iron, US4629804 has announced...

Claims

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Application Information

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IPC IPC(8): C07C271/28C07C269/08
Inventor 高俊杰费维扬
Owner TSINGHUA UNIV