Improving epoxide production using Ti-UVM-7 porous nanosized catalysts

Abstract

Nanosized Ti-UVM-7 materials with a hierarchical system of pores at two different length scales have been prepared through a one-pot procedure by using a simple template agent; the catalytic activity and selectivity of the resulting materials in bulky olefin epoxidation by organic peroxides are the highest reported to date.

Heterogeneous Oxidation of Pyrimidine and Alkyl Thioethers in Ionic Liquids over Mesoporous Ti or Ti/Ge Catalysts

“…This method has been recently applied to the preparation of bimodal mesoporous silicas, and procedural details are described elsewhere. [38,39] Adsorption and desorption isotherms of N 2 at 77 K were obtained using a Micromeritics ASAP 2000 apparatus following degassing of the samples at 150 8C for 12 h under vacuum. Electron probe microanalysis (EPMA) was performed using a Philips SEM-515 instrument.…”

Heterogeneous Catalysis of Alkene Epoxidation

“…The epoxidation of bulkier reactants requires catalysts that provide the characteristic active sites within a more accessible environment. 70Å; this spectrum includes materials such as Ti-SSZ33 [121], Ti-MWW [122], Ti-ITQ6 [123], Ti-SBA15 [124], Ti-MCM41 [125], and Ti-UVM7 [126]. Ti-β can also utilize bulkier alkyl hydroperoxides such as TBHP, unlike TS-1.…”

Titanium-containing desilicated MCM-41 with bimodal pore system as green epoxidation catalyst

“…Both samples exhibit a band centered at ca. 210 nm, which is typically assigned to isolated and tetrahedrally coordinated Ti atoms in the framework of mesoporous titanosilicates [15]. Additionally, no obvious difference on the surface morphology of Ti-MCM-41 and BM-Ti-MCM-41 was observed (see Fig.…”

“…This indicates that the Ti-sites in BM-Ti-MCM-41 are more accessible to the bulky reactants via the large mesopores ( 12.7 nm) than via the unimodal framework mesopores ( 2.7 nm) of Ti-MCM-41. It seems that the activities of BM-Ti-MCM-41 in the epoxidation of this series of alkenes are still promising even when compared with the results obtained with the bimodal mesoporous titanosilicate Ti-UVM-7[15]…”

“…Up to now, most of them are conceptually based on the consequences of decreasing the particle size of the mesoporous materials, and generating interparticle porosity. Despite many efforts devoted to the synthesis of such bimodal mesoporous silicas, studies on application of bimodal mesoporous silicates containing heteroatoms in catalysis are limited [15]. Herein, we reported the preparation and catalysis of bimodal mesoporous Ti-MCM-41 with framework mesopores and intraparticle large mesopores via the alkaline treatment of MCM-41 followed by post-synthesis titanation.…”