Method of preparing methyl cyclo penlene by continuous hydrogenation of methyl cyclo pentadiene

Abstract

The continuous methyl cyclopentadiene hydrogenating process to prepare methyl cyclopentene is one continuous catalytic hydrogenation reaction of the mixture of methyl cyclopentadiene, solvent and hydrogen in a fixed bed catalyst bed. The catalyst includes gamma-Al2O3 as carrier and Pa as active component. The solvent is any one of benzene, toluene, cyclohexane, ethanol, methanol, tertiary amyl alcohol and tertiary butyl alcohol. The reaction system has pressure of 0.9-1.5 MPa and temperature of 60-100 deg.c. The reacted liquid is discharged partially and externally circulated partially with the weight ratio being 1 to 6-12, and the externally circulated liquid after being cooled is mixed with methyl cyclopentadiene material and solvent before being mixed with hydrogen in venturi ejector, atomized into gas-liquid mixture and reacted in the catalyst bed. The catalyst load is 3-6.0 / hr accounted in liquid phase material, and the reacted heat is transferred via external circulation. The present invention has high yield.

Description

technical field [0001] The invention relates to a method for preparing methylcyclopentene by selective hydrogenation of methylcyclopentadiene. Background technique [0002] Methylcyclopentene is an intermediate of many fine chemical products, such as various pesticides and resin intermediates. In the prior art, methylcyclopentene can be obtained by various methods, but the method of hydrogenation of methylcyclopentadiene has the most industrial application prospect. There are few references to the hydrogenation of methylcyclopentadiene to methylcyclopentene, but since it is essentially the same reaction as the hydrogenation of cyclopentadiene to cyclopentene, the latter has the same reference value. For example, US Pat. No. 3,994,986 introduces a method of depolymerizing dicyclopentadiene into cyclopentadiene, followed by two-stage hydrogenation to continuously produce cyclopentene. It adopts a tubular reactor as a hydrogenation reactor, the molar ratio of hydrogen to cyc...

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Problems solved by technology

Since the hydrogenation reaction of (methyl) cyclopentadiene is a strong exothermic reaction, the catalyst bed is prone to runaway temperature during the catalytic hydrogenation process, which leads to catalyst deactivation

In the prior art, the method of installing heat exchange devices in the hydrogenation reactor is mostly used to remove a large amount of reaction heat. The defect of this method is that the uniformity of cooling in the reactor is limited to a certain extent.

It is speculated that there is a local excessive temperature rise in the catalyst bed, which causes partial catalyst deactivation, and (methyl) cyclopentadiene is easily dimerized in this high temperature region to form bis (methyl) cyclopentadiene , which will reduce the yield of (methyl) cyclopentene

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