Preparation method of polymer grade piperyene

Abstract

The invention discloses a method for preparing polymer grade pentadiene. Feeding the raw material of pentadiene into the first extraction tower in existence of polymerization inhibitor, getting extracting agent and pentadiene in tower still; feeding the material got in the first extraction tower into the first analysizing tower, getting pentadiene of high purity containing cyclopentadiene and alkyne; feeding the high pure pentadiene into fractionating tower, getting pentadiene of high purity containinging little amount of cyclopentadiene and alkyne in tower top; feeding the material gor in fractionating tower top into the second extraction tower in existence of polymerization inhibitor 731, getting pentadiene in tower top, feeding the extraction agent, cyclopentadiene and alkyne in tower still into the second analyzing tower; stripping cyclopentadiene and alkyne in the second analyzing tower top, the extraction agent in tower still being returned to the second extraction tower for recyclic use. The invention employs the second-time extractive distillation method, preparing pentadiene from raw material, and is characterized by high extraction accuracy and easy for industrial production.

Description

(1) Technical field

[0001] The invention relates to a preparation method of polymer grade piperylene, in particular to a method for further purification of piperylene obtained by separating carbon five, a by-product of petroleum cracking to ethylene. (2) Background technology

[0002] In the process of producing ethylene from petroleum cracking, C5 by-products account for 12%-14%. In 2005, my country's ethylene processing capacity reached 7.5 million tons, producing more than 1 million tons of C5 by-products. Since the C5 fraction contains diolefins such as isoprene, cyclopentadiene, and piperylene, these diolefins are chemically active and are very important chemical raw materials. The development and utilization of these three kinds of diolefins are earlier in foreign countries and domestically, especially isoprene and cyclopentadiene (dicyclopentadiene) are widely used. Since the purity of piperylene is usually between 65% and 70%, And it contains 20%-25% cyclopentene, c...

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