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) carrying out ether analysis reaction to methyl tert-amyl ether through a catalyst bed layer in a gas phase at 130-300 DEG C; (2) removing methanol in a product of the ether analysis reaction so as to obtain a coarse isoamylene material; (3) adding tertiary amyl alcohol to the coarse isoamylene material, and then carrying out isomerization reaction 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 tertiary amyl alcohol takes the coarse isoamylene as a reference and is 0.1-2.0 percent by weight, the mass space velocity is 1-35 hr, the reaction temperature is 18-45 DEG C, and the reaction pressure is 0.3-1.0MPa. 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 dimerization reaction 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 the isomerization reaction of crude isopentene obtained by etherolysis through a fixed-bed catalyst bed composed of sulfonic acid-based cation exchange resin , In order to increase the content of 2-methyl-2-butene in the method of preparing isoamylene. Background technique [0002] Isoamylene is an important chemical raw material used in the production of resins and pesticide intermediates. Isopentene 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, isopentene The higher the content of 2-methyl-2-butene, the higher the application value. [0003] Isoamylene is mainly present in the carbon five fraction of catalytically cracked gasoline or the carbon five fraction produced by naphtha cracking to produce ethylene. Because these carbon five materials contain ma...

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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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