(560dz) Synthesis of High Purity Norbornene in a Microreactor Under Supercritical Conditions

Synthesis of High Purity Norbornene
in a Microreactor under Supercritical Conditions

Xin Xu, Yin Wu,
Bei Yuan, Zhen Yao, Kun Cao*

(State Key Laboratory of
Chemical Engineering; College of Chemical and Biological Engineering, Zhejiang
University, Hangzhou, P.R. China)

* Corresponding
author: kcao@che.zju.edu.cn.
This work was supported
by the National Natural Science Foundation of China (No. 21676237).

Abstract:

Norbornene (NB) is
obtained by Diels-Alder reaction of cyclopentadiene (CPD) and dienophile
ethylene, while producing by-products tetracyclododecene
(TCD) and tricyclopendiene(TCPD). CPD is unstable at
room temperature and exists in the form of dimer dicyclopentadiene (DCPD),
which is one of the main components in the by-product C5 fraction in the
petroleum cracking process. In recent years, China's petrochemical industry has
developed rapidly. Millions of tons of C5 fractions are produced each year
without efficient way to be utilized. Studying the Diels-Alder reaction of CPD
is conducive to promoting the fine and comprehensive utilization of C5, which
is of great significance to the upgrading of China's petrochemical industry.

Since ethylene does
not contain electron-withdrawing substituents and the energy level difference
between the matching orbitals is large, the Diels-Alder reaction between
ethylene and CPD is carried out at high temperature and pressure with serious
safety concerns. For this reason, a microreactor has been employed in this
work. Supercritical states were introduced by changing the reaction temperature
and pressure. The two substances (E, CPD) participating in the main reaction
are concentrated in the supercritical phase, and the side reaction reactants
(CPD and DCPD or NB) are separated in different phases, which enhances the main
reaction and inhibits the side reaction. The experimental results have shown
that DCPD conversion rate and NB selectivity reached 99.39% and 99.34%, respectively,
at 25MPa and 300^oC.

Keywords: Norbornene;
Microreactor; Supercritical state