Surface-active hollow titanosilicate particles as a Pickering interfacial catalyst for liquid-phase alkene epoxidation reactions

Lv, Guojun; Wang, Fumin; Zhang, Xubin; Binks, Bernard P.

Abstract

Design of catalyst particles bearing excellent catalytic activity and suitable surface wettability is the key to the successful application of Pickering interfacial catalysis. In this study, the epoxidation of 1-hexene and cyclohexene with aqueous hydrogen peroxide over hollow TS-1 zeolite was studied as probe reactions to investigate the influence of catalyst surface wettability on catalytic activity. Hydrophobized hollow TS-1 particles (HTS-1) were fabricated via a post-synthesis desilication treatment with tetrapropylammonium hydroxide (TPAOH) and a post-synthesis silylation treatment with hexamethyldisiloxane (HMDSO). The successful preparation of HTS-1 particles was verified by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR). X-ray diffraction patterns and UV-visible spectra confirmed that hydrophobic modification had no effect on the zeolite structure of HTS-1 particles. Stable Pickering emulsions of aqueous hydrogen peroxide in either 1-hexene or cyclohexene could be prepared using HTS-1 particles as emulsifier and confirmed by cryo-SEM images. The catalytic behaviour in the obtained Pickering emulsions revealed a parabolic distribution of turnover frequency (TOF) values with respect to the hydrophobization degree with 0.2-HMDSO/HTS-1 particles possessing the maximum value of 20.6 h-1 for 1-hexene epoxidation and 8.1 h-1 for cyclohexene epoxidation. In addition, these 0.2-HMDSO/HTS-1 particles showed good re-usability for more than five cycles.

Citation

Lv, G., Wang, F., Zhang, X., & Binks, B. P. (2018). Surface-active hollow titanosilicate particles as a Pickering interfacial catalyst for liquid-phase alkene epoxidation reactions. Langmuir : the ACS journal of surfaces and colloids, 34(1), 302-310. https://doi.org/10.1021/acs.langmuir.7b03633

• Journal Article Type: Article
• Acceptance Date: Dec 12, 2017
• Online Publication Date: Dec 27, 2017
• Publication Date: Jan 9, 2018
• Deposit Date: Sep 18, 2018
• Publicly Available Date: Dec 28, 2018
• Print ISSN: 0743-7463
• Electronic ISSN: 1520-5827
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 34
• Issue: 1
• Pages: 302-310
• DOI: https://doi.org/10.1021/acs.langmuir.7b03633
• Public URL: https://hull-repository.worktribe.com/output/502169
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.langmuir.7b03633