A kind of separation method and separation system of trace benzene in vinyl acetate

Abstract

The invention relates to a separation method of trace benzene in vinyl acetate and a separation system for the separation method. One kind or a mixture of more kinds of alkane of which the carbon number is 10-18 is used as an extracting agent, and through extractive distillation, the trace benzene in the vinyl acetate is separated. The method can remove the trace benzene in the vinyl acetate, so that the content of benzene is reduced to 1PPm or below.

Description

technical field [0001] The invention relates to the technical field of chemical extraction, rectification and separation, in particular to a method for separating trace amounts of benzene in vinyl acetate and a separation system thereof. Background technique [0002] Vinyl acetate is an important chemical basic raw material, which is widely used in the production of chemical and chemical fiber products such as polyvinyl alcohol, coatings, adhesives, vinylon, and films. There are two main production methods of vinyl acetate: ethylene method and acetylene method. Due to the characteristics of the production process, there is a small amount of benzene in the synthesis of vinyl acetate by the acetylene method, and the content is about 2-10PPm. The existence of benzene affects its application in the fields of downstream chemical products such as medical treatment and food. For example, the new national standard requires that the benzene content of the water-based tobacco sizing...

AI Technical Summary

Problems solved by technology

Due to the high cost of cyclodextrins and their low specific selectivity to benzene

Therefore, this technology has not yet been industrialized, and the process of removing benzene is only a preliminary separation, which cannot meet the requirements of separating benzene at the ppm level

[0007] In addition, there is no literature report on the current research on the separation method suitable for trace amounts of benzene in vinyl acetate.

Exploratory studies have found that the difficulty of removing trace amounts of benzene in vinyl acetate is mainly due to the similar physical properties of vinyl acetate and benzene, such as boiling point: benzene 80.1°C, vinyl acetate 72.7°C, molecular size: benzene 0.65nm, vinyl acetate 0.52nm , and the difference in polarity between the two is small, conventional physical methods are not suitable for vinyl acetate-benzene system; and vinyl acetate is chemically active, and the structure of benzene is stable and difficult to undergo chemical reactions, so chemical reaction methods are not suitable for acetic acid Vinyl acetate-benzene system based on vinyl ester

At the same time, the difficulty of vinyl acetate debenzene technology is to further reduce the trace amount of benzene, which is already at the ppm level, to below 1PPm. The requirements for debenzene removal are high and the technology is difficult. The standard debenzene method can be followed

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