Technology of separating dimethyl carbonate from dimethyl carbonate and methanol and water

A technology of dimethyl carbonate and methanol, applied in the field of organic chemical separation, can solve the problems of high energy consumption and equipment cost, lack of economic value, large solvent consumption, etc., and achieves small solvent demand, high operation efficiency, and extraction operation. wide range of effects

Active Publication Date: 2008-07-09
SOUTHWEST RES & DESIGN INST OF CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] To sum up, in the industrial application of the prior art, either the amount of solvent used is too large, the energy consumption and equipment cost are high, and the economic value is lacking; or the solvent has a certain degree of limitation; powerful
In addition, the above separation processes have one thing in common: solvent extraction and distillation are carried out in the same extractive distillation tower, and it is necessary to take into account the favorable extraction temperature and favorable distillation temperature, and the two conflict with each other, making the operation difficult

Method used

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  • Technology of separating dimethyl carbonate from dimethyl carbonate and methanol and water
  • Technology of separating dimethyl carbonate from dimethyl carbonate and methanol and water
  • Technology of separating dimethyl carbonate from dimethyl carbonate and methanol and water

Examples

Experimental program
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Effect test

Embodiment 1-3

[0035] The experiments were carried out in two rectification columns, an extractor and a stratifier. The rectification tower is a stainless steel packed tower with a tower diameter of 1200mm and a packing (stainless steel corrugated packing) height of 18000mm.

[0036] Raw material liquid 9 (containing a small amount of methyl formate and methyl acetate) containing DMC, methyl alcohol and water and come from water phase rectifying tower 4 tower top material 15, product rectifying tower 3 tower top material 14 and methanol recovery tower still material 11 (mainly water) and a small amount of the second solvent n-hexane 10 (boiling point is 68.7 ° C, almost insoluble in water) enter the extractor 1 together, and an appropriate amount of the second solvent n-hexane is added in advance in the extractor 1 to carry out Vapor-liquid, liquid-liquid mass and heat transfer. The gas after this process is drawn out from the top of the extractor 1, and the liquid is drawn out from the bot...

Embodiment 4-6

[0039] The whole process flow is the same as that of Examples 1-3, except that the nonpolar solvents used in Examples 4-6 are cyclohexane, cyclopentane, and n-heptane, and their boiling points are respectively 80.7°C, 49.2°C, and 98.4°C. ℃, the common point is that they are insoluble in water.

[0040] The test conditions and results are shown in the attached tables listed in Fig. 8, Fig. 9 and Fig. 10.

[0041] By adopting the technological method of the patent invention, the azeotrope of methanol and DMC can be separated well, and the purity of the obtained DMC can reach more than 99.90%, and the total yield of DMC is more than 99%. The process has good operability and a wide operating range, and can obtain good separation effects in a wide range of conditions.

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Abstract

The invention provides a process for separating dimethyl carbonate from the mixture of dimethyl carbonate, methanol and water through the procedures of solvent extraction and distillation, wherein the solvent extraction and distillation are carried out in different equipments, and a liquid-liquid extraction system is formed from water and non-polar solvents. The process of the present invention has the advantages of easy operation, easy control, wide range of extraction operation, substantial effect of separation, and circulated use of solvents.

Description

[0001] The invention belongs to the separation of organic chemicals, especially the technical field of separating dimethyl carbonate from dimethyl carbonate and methanol and water mixed liquid. Background technique [0002] There is an azeotrope between methanol and dimethyl carbonate (DMC) (the azeotrope point is 63°C, and the azeotrope composition is CH 3 OH 70%, DMC 30% (mass), the pure product cannot be obtained by ordinary rectification methods. There are mainly two kinds of existing separation techniques, one is extractive distillation and the other is azeotropic distillation. These two separation methods have a large amount of solvent circulation and high energy consumption. [0003] US Patent 3,963,586 discloses a process for separating dimethyl carbonate from dimethyl carbonate, methanol and water. Water is put into the top of the extractive distillation tower at a weight ratio of at least 10:1, and methanol, water and a small amount of dimethyl carbonate flow out f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/96C07C68/08
Inventor 胡文利王学再王国斌许红云张江平刘芃
Owner SOUTHWEST RES & DESIGN INST OF CHEM IND
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