(600bx) Mechanism and Kinetics of Diels–Alder Reaction Between Dicyclopentadiene and 1,3-Butadiene in a High Temperature and High Pressure Continuous Tube Reactor

Yao, Z., Zhejiang University
Cao, K., Zhejiang University

The synthesis of 5-vinyl-2-norbornene( VNB) ,the very critical intermediate of the best third monomer (ethylidenenorbornene, ENB) for EPDM. The most economical way to manufacture VNB is through the Diels–Alder reaction between cyclopentadiene and 1,3-butadiene because of the availability and low cost of the reactant. However, these involves high temperature and high pressure, exothermic reaction, which lead to serious safety concerns and the instability of product's quality. Besides, the existence of various side reactions greatly reduces the selectivity of the reaction and results in tremendous energy and raw meterials waste. Therefore, new means of process enhancing, such as new type of reactors and side-reaction controlling strategies are expected to reinforce stability, safety and economics of process.

In this paper, the combination of previous studies and our investigation of the products of thermal reaction between 1,3-butadiene and cyclopentadiene(CPD) make it possible to describe the process as a set of the parallel and consecutive reactions. The effects of residence time, reaction temperature and ratio between CPD and 1,3-butadiene in feeding on synthesis processes of VNB are investigated. Both the selectivity and conversation of 1,3-butadiene and CPD have been measured. All reactions were conducted in a continuous tube flow reactor. The axial dispersion model has been established to simulate the reaction process, which coincides well with the experimental results. Detailed kinetic parameters are determined, which lay a solid foundation for the optimization of VNB synthesis process. Based on this, the optimum reaction conditions have been evaluated, including residence time, reaction temperature and ratio between CPD and 1,3-butadiene in feeding.