Method for preparing isoamylene from methyl tert-amyl ether

Abstract

The invention relates to a method for preparing isoamylene from methyl tert-amyl ether, which comprises the following steps: (1) methyl tert-amyl ether is subjected to an ether analysis reaction through a catalyst bed layer in a gas phase at 130-300 DEG C; (2) methanol in a product of the ether analysis reaction is removed so as to obtain a coarse isoamylene material; (3) tert butyl alcohol is added to the coarse isoamylene material, and then an isomerization reaction is carried out through the catalyst bed layer in a liquid phase so as to ensure that 2-methyl-1-butylene in the coarse isoamylene is converted into 2-methyl-2-butylene, wherein the addition of the tert butyl alcohol takes the coarse isoamylene as a reference and is 0.2-2.2 percent by weight; the mass space velocity is 1-35 hr, and the reaction temperature is 18-45 DEG C; and the reaction pressure is 0.3-1.0 MPa. Sulfonic acid group cationic exchange resin is used as a catalyst, and the mass exchange capacity of the catalyst is 3-5.5 mmol / g. The method effectively restrains respective or mutual dipolymer reactions of the 2-methyl-2-butylene and the 2-methyl-1-butylene in the process of the isomerization reaction.

Description

technical field [0001] The present invention relates to a method for preparing isopentene from methyl tert-amyl ether, in particular to crude isopentene obtained by etherolysis for further isomerization reaction through a fixed-bed catalyst bed composed of sulfonic acid-based cation exchange resin , to improve the method for preparing isopentene of which 2-methyl-2-butene content. Background technique [0002] Isoamylene is an important chemical raw material used in the production of resins and pesticide intermediates. Isoamyl is usually a mixture of 2-methyl-2-butene and 2-methyl-1-butene. Since only 2-methyl-2-butene is the active ingredient for most reactions, isoamyl The higher the 2-methyl-2-butene content, the higher the application value. [0003] Isoamylene mainly exists in the C5 fraction of catalytic cracked gasoline or the C5 fraction of the by-product of naphtha cracking to ethylene. Since these C5 materials contain many compounds with very close boiling points...

AI Technical Summary

Problems solved by technology

[0004] However, while the isomerization reaction is carried out, 2-methyl-2-butene and 2-methyl-1-butene are all prone to dimerization reactions individually or with each other. Dimer content will reach about 4wt%

Although the dimer can be removed through the refining process, this will lead to a decrease in product yield and an increase in energy consumption

On the other hand, the reaction heat of the dimerization reaction will also cause abnormal fluctuations in the temperature of the catalyst bed, making it difficult to control the isomerization reaction smoothly.

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