Synthesis And Separation Of The Dicyclopentadiene And Methyl Cyclopentadiene Dimer

With the development of ethylene industry, the yield of cracking C9fraction has continuously increased.The components of cracking C9are complex, which contain a large number of C9aromatics, styrene, indene, naphthalene, dicyclopentadiene (DCPD), methyl cyclopentadiene dimer (DMCPD), cyclopentadiene with methyl cyclopentadiene (CPD+MCPD) dimer, etc. DCPD (CPD) and DMCPD (MCPD) are important chemical raw materials and valuable products, which have broad market prospects.After reading aomunts of literatures and analyzing the cracking C9raw materials, liquid phase depolymerization process for separating DCPD and DMCPD was used. The high purity CPD and the crude MCPD was obtained by separation of the depolymerized monomer. DCPD (>97%) was obtained by dimerization of the CPD while DMCPD (>95%) was obtained after cutting the light constituent and heavy constituent. The separation condition and equipment parameters were optimized as follow:1. Cleavage column and monomer separating column were used in series to depolymerize. The optimal theoretical plate for cleavage column was15and the optimal theoretical plate for monomer separating column was20. The mixture of CPD and MCPD was obtained from the top of the cleavage column. MCPD was obtained form the fifth plate. CPD was obtained form the bottom of the column. The best depolymerization extraction temperature was80～90℃, the best extraction temperature at the top of the monomer separating column was40℃and the best siding extraction temperature was70～80℃. The best reflux ratio for the top of the cleavage column was1:1, the best reflux ratio for the top of the monomer separating column was1:1and the best reflux ration for siding was2:1. The depolymerization temperature for the cleavage column was180～200℃. The bottom temperature for the monomer separating column was180～200℃.500ppm para-quinone was used as the polymerization inhibitor.2. With the dimerization reaction of MCPD and CPD, the highly purified DCPD and the crude DMCPD was obtained. The polymerization temperature was80～90℃and the residence time was540min. 3. During the purification of DMCPD, the fractionating temperature was115～125℃(0.095MPa). The top of column was under internal reflux. By the separation of cutting the light constituent and heavy constituent, the highly purified DMCPD was obtained. The cut light temperature was lower than90℃and the cut heavy temperature was lower than105℃. The optimal extraction temperature for DMCPD was90～105℃.The whole process was simulated by Aspen Plus. A set of production device was developed to separate methyl cyclopentadiene dimer and dicyclopentadiene from the cracking C9fraction. After the device put into operation, the production line is operating stably. The purity of DMCPD is more than95%and DCPD is more than97%.