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Method and system for producing dimethyl carbonate (DMC) by using urea two-step method

A technology of dimethyl carbonate and cycloalkylene carbonate, which is applied in the field of chemical technology, can solve the problems of many side reactions, single product structure, and low conversion rate of urea in one pass, so as to reduce equipment investment costs, avoid discharge of three wastes, The effect of high conversion rate of urea per pass

Inactive Publication Date: 2017-11-17
SINOPEC SHANGHAI ENG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is simple in process and easy to operate, but there are still obvious defects, that is, the single-pass conversion rate of urea is low, and there are many side reactions, and the product structure is single at the same time.

Method used

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  • Method and system for producing dimethyl carbonate (DMC) by using urea two-step method

Examples

Experimental program
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Effect test

Embodiment 1

[0067] use as figure 1 The process flow shown produces dimethyl carbonate:

[0068] (1) Urea reacts with 1,2-propylene glycol to generate propylene carbonate

[0069] At first, in batching system, raw material urea and catalyst A are miscible in 1,2-propanediol, then, send into cycloalkylene carbonate synthesis reactor 1 and react, wherein, 1,2-propanediol: urea (mol Ratio)=4:1, the mass concentration of catalyst A is 2%, and catalyst A is Ni oxide supported by zinc oxide; the type of reactor 1 is full mixed flow, the total feed is 619kg / hr, and the reaction condition is 160°C , 0.102MPaA. The conversion rate of urea is 100%, the selectivity of propylene carbonate is 95%, the reaction product is 56.7kg / hr, NH 3 It is discharged from the ammonia gas recovery port and passed into the urea synthesis unit for the urea synthesis process. The reaction product propylene carbonate, together with unreacted 1,2-propanediol and catalyst A, is discharged from the bottom into the filte...

Embodiment 2

[0079] use as figure 1 The process flow shown produces dimethyl carbonate:

[0080] (1) Urea reacts with ethylene glycol to form ethylene carbonate

[0081] First, in the batching system, the raw material urea and catalyst A are miscible in ethylene glycol, and then sent to cycloalkylene carbonate synthesis reactor 1 for reaction, wherein, ethylene glycol: urea (molar ratio)=4 : 1, the mass concentration of catalyst A is 2%, and catalyst A is Ni oxide including zinc oxide support; the type of the reactor 1 is full mixed flow, the total feed is 534kg / hr, and the reaction conditions are 170°C and 0.102MPaA. The conversion rate of urea is 100%, the selectivity of ethylene carbonate is 95%, the reaction product is 56.7kg / hr, NH 3 It is discharged from the ammonia gas recovery port and passed into the urea synthesis unit for the urea synthesis process. The reaction product ethylene carbonate, together with unreacted ethylene glycol and catalyst A, is discharged from the bottom i...

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Abstract

The invention provides a method for producing dimethyl carbonate (DMC) by using a urea two-step method and a system for producing the dimethyl carbonate by using the method. The method mainly comprises the following steps: S1, in a synthesis unit of cyclic alkylene carbonate, using a catalyst A to catalyze urea to react with dihydric alcohol to generate the cyclic alkylene carbonate; then recovering ammonia gas, filtering a discharged material by a filter and recycling the catalyst A; transporting the filtered discharged material to a synthesis unit of the dimethyl carbonate; S2, in the synthesis unit of the dimethyl carbonate, using a catalyst B to catalyze the cyclic alkylene carbonate to carry out transesterification with methanol to generate a dimethyl carbonate product. The method and the system provided by the invention can avoid discharge of three wastes to a maximum extent and have the advantages of safety and easiness in control, mild reaction conditions, convenience in adjustment of a product scheme and high single-pass conversion rate of the urea; in addition, the investment cost of equipment is greatly reduced or even the co-production of the dimethyl carbonate and the cyclic alkylene carbonate can be realized, so that the method and the system have wide application value and a good market prospect.

Description

technical field [0001] The invention belongs to the field of chemical technology, and in particular relates to a method for producing dimethyl carbonate by a two-step method of urea, and a system for producing dimethyl carbonate by using the method. Background technique [0002] Dimethyl carbonate (DMC) is an internationally recognized green and environmentally friendly chemical raw material. It can replace highly toxic phosgene, benzene and other bulk chemical raw materials. , Flavor enhancers, food preservatives, lubricating oil additives, cleaning oil additives and other fields have been more and more widely used, with very broad market development prospects, known as the "new cornerstone" of today's organic synthesis. [0003] At present, there are many methods for the synthesis of dimethyl carbonate. The phosgene method is the earliest industrialized DMC production process, but the method has a long production process, low product yield, high cost, and phosgene is highl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/96C07C68/06C07C68/08C07D317/36C07D317/38
CPCC07C68/065C07C68/08C07D317/36C07D317/38C07C69/96Y02P20/584
Inventor 刘肖肖陈迎贾微裴凯凯徐曼张艺张翼
Owner SINOPEC SHANGHAI ENG
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