Oxidation of Benzene to Phenol with Hydrogen Peroxide Catalyzed by a Modified Titanium Silicalite (TS‐1B)

Abstract

The hydroxylation of benzene to phenol with hydrogen peroxide was investigated using different solvents and a series of catalysts, obtained by modification of titanium silicalite (TS-1). The best results were obtained after post-synthesis treatment of TS-1 with NH 4 HF 2 and H 2 O 2 . The new catalyst (TS-1B), used in the presence of a particular co-solvent (sulfolane) is able to protect the produced phenol from over-oxidation and dramatically enhanced the selectivity of the reaction.

Switching off H2O2 Decomposition during TS-1 Catalysed Epoxidation via Post-Synthetic Active Site Modification

“…According to this provisional characterisation, it may tentatively be attributed that NH4HF2 treatment leads to a change to the framework Ti IV atoms. We note that the spectral data presented in Part 1 is in good agreement to the scattered reports of TS-1B in the open literature [8][9][10].…”

“…The post-synthetic modification of calcined TS-1 with NH4HF2 and H2O2 was performed in an aqueous solution under the conditions optimised by Bianchi and co-workers for 4 h (catalyst henceforth denoted TS-1B) [8][9][10]. The treatment does not lead to any substantial differences in crystallographic structure, porosity or Ti loading, with each of these parameters remaining constant following NH4HF2 treatment.…”

“…Whilst previous studies of TS-1B have focused upon aromatic hydroxylation [8][9][10], we chose to investigate the impact of NH4HF2 treatment on the epoxidation activity of TS-1. Allyl alcohol was chosen as a model HPPO substrate [6].…”

“…Recent work has demonstrated that post-synthetic modification of TS-1 with NH4HF2 leads to exciting improvements for aromatic hydroxylation activity and selectivity [8][9][10]. Despite this, the impact of this treatment on: (i) the active site speciation; and (ii) the activity of TS-1 for other oxidation reactions, particularly epoxidation, remains almost unexplored.…”

Direct Synthesis of Phenol from Benzene over Platinum-loaded Tungsten(VI) Oxide Photocatalysts with Water and Molecular Oxygen

“…1 Direct synthesis of phenol from benzene in a one-step reaction, especially using environmentally benign oxidants such as molecular oxygen (O 2 ) or water, is highly desirable, and thus have been extensively studied. [2][3][4] However there have been few catalytic process that enables high benzene conversion with high phenol selectivity by using such environmentally benign oxidants (O 2 and/or water). Photocatalysis on semiconductor materials may be one of the candidates for such clean and direct synthesis of phenol from benzene.…”