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Method for extracting high purity methyl acetate in methyl acetate-methanol-water mixed liquor

A technology of methyl acetate and mixed solution, which is applied in the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of organic compounds, etc., and can solve the problems of high energy consumption in rectification, complicated process, and lack of high-purity methyl acetate, etc. problems, to achieve the effect of low equipment requirements, simple process and low energy consumption

Active Publication Date: 2014-12-10
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Methyl acetate, a by-product of PTA in industry, is a mixed solution of methyl acetate, methanol and water, generally consisting of 78-92wt% methyl acetate, 1-21wt% methanol and 1-21wt% water. The ester-methanol-water mixture is easy to form binary and ternary azeotropes, and it is difficult to obtain high-purity methyl acetate by ordinary distillation methods
At present, the method of combining salt effect separation and rectification can be used in industry to purify methyl acetate to a higher concentration, and then further purify methyl acetate to 99.8% by rectification to meet the requirements of industrial production of high-purity methyl acetate. requirements, but the method is complex and requires high rectification energy consumption
In the "Study on the Extraction and Separation of Methyl Acetate-Methanol-Water Compound Salt" published in [Journal of Chemical Engineering of Colleges and Universities] Volume 21, Issue 2, Yang Dongjie and others used magnesium chloride, potassium acetate and water. 3 The compound salt extractant of compound salt extractant is carried out separation and purification to this system, and the purity of methyl acetate is raised to more than 98% by 87%, but still can't reach the requirement of high-purity methyl acetate (purity is 99.8%)
In the domestic patent 200510002905.3, Chen Jian and others obtained high-purity methyl acetate by methods such as adsorption distillation and liquid phase adsorption, but these methods are complex in process and difficult in industrial production

Method used

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  • Method for extracting high purity methyl acetate in methyl acetate-methanol-water mixed liquor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] With the near azeotrope of methyl acetate-methanol-water as raw material F (by the methyl acetate of 78.02wt%, the methyl alcohol of 18.25wt% and the water of 3.73wt%), extraction process flow is as follows figure 1 shown.

[0016] The first extractant S1 is an aqueous solution of ammonium chloride with a mass fraction of 5 wt%. The first extractant S1 and methyl acetate-methanol-water mixture F are added to the first extraction tower I for cross-flow extraction, and the amount of methyl acetate - Twice the volume of the methanol-water mixture F, the extraction temperature in the first extraction tower I is 25° C., and the pressure is 1 atm. The first extraction phase obtained 99.3wt% methyl acetate crude product E, wherein the methanol content was 0.5wt%, and the water content was 0.2wt%. The main components of the first raffinate phase R1 were the first extractant S1 and methanol.

[0017] Then take glycerol as the second extractant S2, add glycerin and methyl acetat...

Embodiment 2

[0022] The operation is basically the same as in Example 1, except that: the first extractant S1 is a potassium acetate aqueous solution with a mass fraction of 6%, and the consumption is 3 times the volume of the methyl acetate-methanol-water mixed solution F, and the first extraction tower The extraction temperature of I is 30° C.; the amount of glycerol is the same as that of crude product E of methyl acetate. The purity of the methyl acetate crude product E is 99%, wherein, the methanol content is 0.48wt%, and the water content is 0.52wt%; the purity of the high-purity methyl acetate product P is 99.82%, and the recovery rate is 97.5%.

Embodiment 3

[0024] Operation is basically the same as in Example 1, except that the raw material F consists of 78wt% methyl acetate, 1wt% methyl alcohol and 21wt% water, and the first extraction agent S1 is a calcium chloride aqueous solution with a mass fraction of 5%, and the consumption is 3 times the volume of methyl acetate-methanol-water mixture F, the extraction temperature of the first extraction tower I is 30°C; the amount of glycerol is 2 times the volume of the crude product E of methyl acetate, the extraction temperature of the second extraction tower II is 30°C. The purity of the methyl acetate crude product E is 98.8%, wherein, the methanol content is 0.48wt%, and the water content is 0.54wt%; the purity of the high-purity methyl acetate product P is 99.81%, and the recovery rate is 97.5%.

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Abstract

The invention relates to a method for extracting high purity methyl acetate in methyl acetate-methanol-water mixed liquor, which comprises the following steps: extracting a first extract phase namely methyl acetate crude product from methyl acetate-methanol-water mixed liquor with a first extractant, then extracting second extract phase namely high purity methyl acetate high purity methyl acetate with a second extractant glycerin, wherein the first extractant is ammonium chloride, potassium acetate, calcium chloride or their mixture aqueous solution, and the mass fraction of the salt is 3-8%. According to the invention, an industrial methyl acetate byproduct is taken as a raw material to prepare methyl acetate with purity more than 99.8%, and the recovery rate is more than 97%, the technology is simple, the equipment requirement is low, compared with the rectification, the energy consumption is low, and the method is adapted to industrial production application.

Description

technical field [0001] The invention relates to a method for extracting high-purity methyl acetate from methyl acetate-methanol-water mixed liquid. Background technique [0002] Methyl acetate is an important solvent and organic chemical raw material. High-purity methyl acetate can be used to synthesize acetic acid, acetic anhydride, methyl acrylate, vinyl acetate and acetamide. The market price is high, and the production of high-purity methyl acetate has Huge economic benefits. At present, there are two main sources of industrial high-purity methyl acetate, one is obtained by chemical synthesis, and the other is obtained by chemical purification. Methyl acetate, a by-product of PTA in industry, is a mixed solution of methyl acetate, methanol and water, generally consisting of 78-92wt% methyl acetate, 1-21wt% methanol and 1-21wt% water. The ester-methanol-water mixture is easy to form binary and ternary azeotropes, and it is difficult to obtain high-purity methyl acetate ...

Claims

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Application Information

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IPC IPC(8): C07C69/12C07C67/58
Inventor 顾美娟汪洋胡维强刘宗健
Owner CHINA PETROLEUM & CHEM CORP