Method for preparing high pure methyl acetate through adsorption of liquid phase

Abstract

The present invention utilizes the processes of extraction rectification, liquid-phase adsorption, variable temperature purge desorption regeneration and methyl alcohol rectification to conveniently and high-effectively prepare high-purity methyl acetate with high value from industrial waste liquid (gas) containing methyl acetate, at the same time, said invention can obtain another main components in waste liquid (gas)-methyl alcohol.

Description

technical field [0001] The invention belongs to the technical scope of organic material preparation, and particularly relates to a method for preparing high-purity methyl acetate from industrial waste liquid (exhaust gas) containing methyl acetate. The method can also be used for the production of acetic acid by the esterification process of acetic acid and methanol Refined products of methyl esters. Background technique [0002] In the industrial production process of polyvinyl alcohol and terephthalic acid, a large amount of waste liquid (gas) containing methyl acetate is produced. Generally speaking, 1.5-1.7 tons of methyl acetate is produced for every ton of polyvinyl alcohol produced; a 200,000-ton / year purified terephthalic acid (PTA) production plant will produce 1,600 tons of methyl acetate per year. These methyl acetates also contain impurities such as methanol and water, which make their performance very unstable and limit their industrial application. Since meth...

AI Technical Summary

Problems solved by technology

These methyl acetates also contain impurities such as methanol and water, which make their performance very unstable and limit their industrial application.

Since methanol and water are easy to form azeotropes with methyl acetate and are excellent solvents, it is difficult to separate them by ordinary distillation or extraction methods.

At present, most of these waste liquids (gas) are processed by circulating hydrolysis or returning to the furnace for combustion. The energy consumption and material consumption of the process are extremely high, and the requirements for equipment anticorrosion are also very high. The acetic acid and methanol produced by the carbonylation method are combined. Methanol is uncompetitive in price and is a serious waste of methyl acetate resources

In addition, in the process of producing methyl acetate through the esterification of acetic acid and methanol, there is also the problem of low product purity due to the difficulty in separating methyl acetate and methanol

At present, the high-purity methyl acetate with a methyl acetate content of more than 99.8% that is urgently needed in the market is produced through complex processes such as esterification, extraction and rectification of methanol and acetic acid, which requires expensive corrosion-resistant extraction and rectification towers. Greatly increased the production cost of high-purity methyl acetate

[0003] For this type of methyl acetate production waste liquid (gas) containing impurities such as methanol and water, the main problem is that methyl acetate and methanol, water and other substances in the waste liquid (gas) will form azeotropes. Distillation and extraction methods are difficult to separate it; and if membrane separation technology is used, it is difficult to obtain high-purity methyl acetate

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