Method for Production of Polymerization Grade Isoprene via C5Fraction Separation Developed by Shanghai Petrochemical Company

The SINOPEC Shanghai Petrochemical Company, Ltd. has developed a method for separating C5fraction to manufacture the polymerization grade isoprene. The process scheme includes the following procedures: The raw C5fraction is subjected to rectification to remove the light fraction containing impurities. The raw feed material is subjected to preheating and dimerization reaction to convert a part of cyclopentadiene substances into dicyclopentadiene with the remainder being subjected to rectification to extract a part of isoprene, which is concentrated at the tower overhead. The material remaining in the kettle of the preceding tower is then subjected to second thermal dimerization reaction to convert the remaining cyclopentadiene into dicyclopentadiene with the remainder undergoing separation via rectification to extract the remaining isoprene which is concentrated in the tower overhead, while dicyclopentadiene and piperylene are concentrated in the tower kettle. The isoprene material obtained in the previous phase is further subjected to extractive rectification and purification to yield the polymerization grade isoprene. The advantage of this method is to effectively inhibit the co-polymerization of isoprene and cyclopentadiene in the course of heating and separation to significantly reduce the loss of isoprene and cyclopentadiene.