Method for preparing high-purity dicyclopentadiene by taking crude dicyclopentadiene as raw material

Abstract

The invention relates to a method for preparing high-purity dicyclopentadiene by using crude dicyclopentadiene as a raw material, which comprises the following steps: (1) enabling the crude dicyclopentadiene raw material to enter a fixed bed reactor to carry out selective hydrogenation reaction, wherein the catalyst is Pt and Pb modified Pd catalyst; (2) feeding the hydrogenated material into a depolymerization reaction rectifying tower, and depolymerizing to generate cyclopentadiene; and (3) polymerizing cyclopentadiene through a first-stage polymerization reactor, a second-stage polymerization reactor and a third-stage polymerization reactor to obtain dicyclopentadiene. According to the method, crude dicyclopentadiene separated from an ethylene by-product C5 fraction is used as a raw material, and norbornene is converted into a relatively stable substance through hydrogenation by adopting a selective hydrogenation process, so that the side reaction of the raw material in a depolymerization reaction rectifying tower can be effectively eliminated, and high-purity dicyclopentadiene with the content of more than 99% is obtained.

Description

technical field [0001] The invention relates to dicyclopentadiene, in particular to a method for preparing high-purity dicyclopentadiene from crude dicyclopentadiene. Background technique [0002] Dicyclopentadiene (DCPD) is an important fine chemical raw material, mainly derived from the by-product C5 fraction of petroleum cracking to ethylene, and the main way is to separate cyclopentadiene (CPD) in the C5 fraction after polymerization. Due to side reactions in the polymerization process, the obtained crude dicyclopentadiene product has a purity of about 80%, and its main by-product is norbornene (a copolymer of cyclopentadiene and isoprene). Usually crude dicyclopentadiene is used to produce resin or replace part of phthalic anhydride to produce unsaturated polyester, and the added value is not high; while ultra-high purity (greater than 99%) bicyclic can be used to produce reaction injection molding engineering plastic polydicyclopentadiene ( PDCPD), its products can re...

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Problems solved by technology

However, because IP and CPD are prone to polymerization reactions, and there is not much difference between the copolymerization rate of CPD dimerization and IP and CPD, the depth of reaction is difficult to control. In order to ensure the purity of dicyclopentadiene, there will be more unpolymerized IP and CPD are circulated from the top of the tower, which affects the yield and greatly increases energy consumption

[0004] This shows that there are also obvious defects in the existing technology for removing impurities (isoprene) in cyclopentadiene, which cannot meet the high purity and high yield of product dicyclopentadiene simultaneously.

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