Modified Ti-MWW Zeolite as a Highly Efficient Catalyst for the Cyclopentene Epoxidation Reaction.

Wen Tong,Peng Wu,Hao Xu,Jinpeng Yin,Luoyi Ding

doi:10.3389/fchem.2020.585347

Abstract

The liquid-phase epoxidation of cyclopentene (CPE) was performed in the Ti-zeolite/H2O2 catalytic system for the clean synthesis of cyclopentene oxide. Among all the Ti-zeolites (Ti-Beta, Ti-MOR, Ti-MCM-68, TS-1, TS-2, and Ti-MWW) investigated in the present study, Ti-MWW provided relatively lower CPE conversion of 13% due to the diffusion constrains but a higher CPO selectivity of 99.5%. The catalytic performance of Ti-MWW was significantly enhanced by piperidine (PI) treatment, with the CPE conversion and CPO selectivity increased to 97.8 and 99.9%, respectively. The structural rearrangement upon PI treatment converted the 3-dimensional (3D) MWW structure to a 2D lamellar one, which enlarged the interlayer space and greatly alleviated the diffusion constrains of cyclic cyclopentene. Furthermore, the newly constructed “open site” six-coordinated Ti active sites with PI as the ligand exhibited higher catalytic activity. The two factors contributed to more significant enhancement of the activity upon PI-assisted structural arrangement compared to the cases in linear alkenes.

Highlights

Epoxy compounds, as important organic intermediates and chemical raw materials, can undergo ring-opening reactions with water, alcohols, amines, ammonia, or carboxylic acids to form a series of fine and bulk chemicals in the fields of petrochemical industry, polymer synthesis, and pharmaceuticals (Imamura et al, 1989; Yuan et al, 2011; Sharma et al, 2014; Jiang et al, 2019).The epoxidation of olefins is a typical way to produce epoxides
As shown in SEM images (Supplementary Figure 2), Ti-MWW possessed unique thin platelet morphology with the thickness of ∼50 nm, which was quite different from Ti-Beta (50 nm), Ti-MOR
In order to select a suitable catalyst for the cyclopentene epoxidation process, the catalytic performance of the above titanosilicates was firstly investigated under the same reaction conditions (Table 1)

Summary

Introduction

As important organic intermediates and chemical raw materials, can undergo ring-opening reactions with water, alcohols, amines, ammonia, or carboxylic acids to form a series of fine and bulk chemicals in the fields of petrochemical industry, polymer synthesis, and pharmaceuticals (Imamura et al, 1989; Yuan et al, 2011; Sharma et al, 2014; Jiang et al, 2019).The epoxidation of olefins is a typical way to produce epoxides. As important organic intermediates and chemical raw materials, can undergo ring-opening reactions with water, alcohols, amines, ammonia, or carboxylic acids to form a series of fine and bulk chemicals in the fields of petrochemical industry, polymer synthesis, and pharmaceuticals (Imamura et al, 1989; Yuan et al, 2011; Sharma et al, 2014; Jiang et al, 2019). The main product of cyclopentene epoxidation is 1,2-epoxycyclopentane (CPO), which is widely used as the intermediate in medicine and organic synthesis (Milen et al, 2000; Huang et al., 2015; Seol et al, 2020)

Methods

Results

Conclusion