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

Abstract

The liquid-phase epoxidation of cyclopentene (CPE) was performed in the Ti-zeolite/H 2 O 2 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.

Hydrophilic Ti-MWW for catalyzing epoxidation of allyl alcohol

“…Afterward, Ti-MWW with 12MR large cavities and surface half cups was developed. Ti-MWW exhibits higher conversion than TS-1 in the propylene and cyclohexene epoxidation [15] . The catalytic activity of Ti-MWW in olefin epoxidation reactions can be further enhanced by post-modifications, such as fluoride treatment or piperidine (PI)-assisted 3D to 2D structural transformation [16][17][18][19][20] .…”

“…Two characteristic diffraction peaks at 2θ = 3.5° and 6.7° attributed to the (001) and (002) crystal planes of layered MWW structure, respectively, appeared in the XRD pattern of Re-Ti-MWW due to the structural change from 3D Ti-MWW to 2D layered Re-Ti-MWW with the assistance of PI [Scheme 1]. The interlayer Si-O-Si linkages were broken in this process, allowing the PI molecules to be inserted between the MWW layers [15] . The presence of PI molecules in Re-Ti-MWW was further confirmed by the TG analysis and [13] C MAS NMR spectrum [Supplementary Figure 1].…”

Facile and fast synthesis of highly active Lewis acid MWW zeolite from pure silica ITQ-1

“…[2][3][4][5][6][7][8][9][10] Therefore, MWW type lamella zeolites are extensively studied and employed as attractive catalysts. 11,12 Lewis acid zeolites are outstanding catalysts for the activation and conversion of oxygenated molecules, especially for the upgrading of bio-based renewables. [13][14][15][16][17] Sn-Containing Lewis acid MWW, first reported by Wu et al, 18 has shown encouraging catalytic performance in many types of reactions, including Baeyer-Villiger oxidation, 18,19 MPV hydrogen trans-fer 20 and sugar conversion.…”

“…2–10 Therefore, MWW type lamella zeolites are extensively studied and employed as attractive catalysts. 11,12…”

Assembly of SBA‐15 Derived Hybrid Heterogeneous Catalysts for Liquid Phase Cyclopentene Epoxidation

“…[1] Cyclopentene oxide, a significant intermediate and raw material in organic synthesis, [2] can be synthesized from epoxidation of cyclopentene, [3] since abundant cyclopentene could be easily obtained via selective cyclopentadiene hydrogenation, the direct synthesis of cyclopentene oxide from cyclopentene epoxidation with H 2 O 2 is a convenient and economical way of utilizing cyclopentadiene, a mian by-product of C5 fraction in petrochemical industry. [4] Several investigation for cyclopentene epoxidation over recyclable heterogeneous catalysts have also been decribed, [5] nevertheless, in these systems, low accessibility between organic cyclopentene and H 2 O 2 generally occurs due to hydrophilicity of the supported catalysts resulting in low catalytic activity. Successful incorporation of suitable organic moieties in a porous inorganic support network can introduce more hydrophobicity at the resulting nanostructured materials surface, which is desirable for their catalytic application in chemical transformations in liquid-phase.…”