ISOLATION AND PURIFICATION OF ISOPRENE FROM CYCLOPENTADIENE

Abstract

Isoprene is a basic monomer in the petrochemical industry. It is used in the synthetic rubber production for the manufacture of rubber products for the electrical, aviation and engineering industries, for the manufacture of food and medical products. In the Republic of Bashkortostan, Sintez-Kauchuk OJSC (Sterlitamak) produces isoprene by the two-stage dehydrogenation of isopentane with an annual product output of hundreds of thousands of tons. The disadvantage of this technology for producing isoprene is the significant content of impurities in raw isoprene, which seriously affect the kinetics of polymerization and the quality of the final product. Of all the impurities present in the monomer, cyclopentadiene is the most detrimental to the stereoregular polymerization process. Its content in isoprene should not exceed 0.0001 % wt. Due to the urgency of the problem, a technical solution was developed to remove cyclopentadiene impurities from monomers.Currently, there is a problem of accumulation of cyclopentadiene in the system of purification and treatment of isoprene at the operating production. The paper proposes to purify isoprene from cyclopentadiene before the stage of extractive distillation. This purification method allows to reduce the content of cyclopentadiene in the isoprene-isoamylene fraction from 0.10 % wt. to 0.00014 % wt, which reduces its concentration in all recycle flows of the isoprene isolation and purification system. To implement this solution, laboratory experiments were carried out to purify the isoamylene-isoprene fraction formed at the second stage of isopentane dehydrogenation. In order to assess the energy efficiency of the studied method for reducing cyclopentadiene, a computer model of the isoprene isolation and purification process was built in the Honeywell Unisim Design software environment.