Authors: Awoke, Y; Chebude, Y; Diaz, I

Article.
Catal. Today. vol: 390. page: 0920-5861.
Date: may-01. 2022.
Doi: 10.1016/j.cattod.2021.10.010.

Abstract:
The aim of this study is to obtain Ti-containing Periodic Mesoporous Organosilica (PMO) materials with catalytic activity in epoxidation reactions. Characterization of the PMO materials using X ray diffraction, N-2 sorption isotherms, chemical analysis (ICP-OES) and UV-vis spectroscopy reveals that the Ti-PMO materials possess or-dered 2-dimensional hexagonal mesostructures, high surface areas (593-944 m(2)/g), uniform pore sizes (4.5-11 nm), large pore volumes (0.59-1.62 cm(3)/g), and tetrahedrally incorporated Ti(IV) species on the surface of the pore walls. The PMO materials with fiber-like particle morphology, which may hinder the diffusion of substrates, have been compared with those of plate-like morphology in which diffusion problems may be avoided. The catalytic activities of these materials were tested in epoxidation of cyclohexene with an optimum conversion rate of 30.5% and good epoxide selectivity (93.8%). Selected Ti-PMO materials were also effective for the epoxidation of vernonia oil, a naturally expoxidized triglyceride oil, using tert-butyl hydroperoxide as an oxidant..