Method for synthesizing hexamethylene carbamate

A technology of cyclohexyl carbamate and synthesis method, which is applied in the field of synthesis of cyclohexyl carbamate, can solve problems such as low yield, and achieve strong practicability, high reaction selectivity and yield, and excellent reaction conditions mild effect

Inactive Publication Date: 2009-07-01
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Disadvantages: At high temperature, one-step reaction of N, N'-dialkylurea and dialkyl carbonate to synthesize the corresponding isocyanate, resulting in lower yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] In a 0.5 liter autoclave, add 32.4 grams of dimethyl carbonate (DMC), 4.4 grams of N, N'-dicyclohexylurea (DCU), catalyst NaOCH 3 0.2 g, at a temperature of 180° C., a pressure of 1.5 MPa and a rotation speed of 500 rpm, the temperature, pressure and rotation speed were maintained for 5 hours and the reaction was completed. When the temperature was cooled down to room temperature, the reactor was opened to take a sample to obtain a clear liquid and a sample 1 with a solid at the bottom, and the sample 1 was dissolved in 100ml of hot ethanol at 60°C for chromatographic analysis. Distill the hot ethanol solution at 80°C and 60mmHg to obtain ethanol and DMC. Then raise the temperature to 140°C, keep the vacuum constant, and distill to obtain methyl cyclohexylcarbamate. The remaining unreacted DCU, catalyst and a small amount of by-products are extracted with cold ethanol to recover DCU for recycling. The catalyst and a small amount of by-products are separated using dist...

Embodiment 2

[0029] In a 2 liter autoclave, add 650 grams of dimethyl carbonate (DMC), 88 grams of N, N'-dicyclohexylurea (DCU), 4 grams of catalyst MgO, at a temperature of 180 ° C and a pressure of 1.5 MPa Under the condition of 500 r / min and the rotating speed, the temperature, pressure and rotating speed were kept for 5 hours and then the reaction was finished. When the temperature was cooled down to room temperature, the reactor was opened to take a sample to obtain a clear liquid and a sample 1 with solids at the bottom. The sample 1 was dissolved in 100ml of hot ethanol at 60°C to recover the catalyst by filtration, and then chromatographic analysis was performed. Distill the hot ethanol solution at 80°C and 60mmHg to obtain ethanol and DMC. Then raise the temperature to 140°C, keep the vacuum constant, and distill to obtain methyl cyclohexylcarbamate. The remaining unreacted DCU and a small amount of by-products are extracted with cold ethanol to recover DCU for recycling. The ch...

Embodiment 3

[0031] In a 0.5 liter autoclave, add 46 grams of diethyl carbonate (DEC), 4.4 grams of N, N'-dicyclohexylurea (DCU), catalyst Cs 2 CO 30.2 g, at a temperature of 180° C., a pressure of 1.0 MPa and a rotation speed of 500 rpm, the temperature, pressure and rotation speed were maintained for 5 hours to complete the reaction. When the temperature was cooled down to room temperature, the reactor was opened to take a sample to obtain a clear liquid and a sample 1 with a solid at the bottom, and the sample 1 was dissolved in 100ml of hot ethanol at 60°C for chromatographic analysis. Distill the hot ethanol solution at 90°C and 60mmHg to obtain ethanol and DEC. Then raise the temperature to 135°C, keep the vacuum constant, and distill to obtain ethyl cyclohexyl carbamate. The remaining unreacted DCU, catalyst and a small amount of by-products are extracted with cold ethanol to recover DCU for recycling. The catalyst and a small amount of by-products are separated using distilled w...

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PUM

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Abstract

The invention discloses a method for synthesizing cyclohexyl carbamate, which is to select dialkyl carbonate and N,N'-dicyclohexylurea as reactants, control the reaction temperature to be between 100 and 250 DEG C and the reaction pressure to be between 0.5 and 2.0 MPa, and synthesize the cyclohexyl carbamate under the action of a catalyst. The method mainly has the characteristics of mild reaction conditions, cheap and easily obtained catalyst, easy reclaiming, good reusability, economic atomic reaction, high purity of products obtained by separation, small number of byproducts, and high industrial application value.

Description

technical field [0001] The present invention relates to a kind of synthetic method of cyclohexyl carbamate, specifically the method for catalyzing dialkyl carbonate and N, N'-dicyclohexyl urea to synthesize cyclohexyl carbamate. Background technique [0002] Isocyanate is an important class of organic synthesis intermediates and the main raw material for polyurethane synthesis, which can be widely used in polymer materials such as polyurethane, coatings, dyes and pesticides. According to statistics, the demand for various isocyanates at home and abroad is increasing by a large margin. In the traditional isocyanate synthesis industry, most products are synthesized by phosgene method. The synthesis process has disadvantages such as long route, high cost, highly toxic raw materials, corrosion of equipment by hydrochloric acid by-product, difficulty in removing residual chlorine in the product, and serious environmental pollution. With the enhancement of environmental awarenes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C271/24C07C269/00
Inventor 邓友全郭晓光尚建鹏李健王利国马祥元
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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