Ti-Si CATALYSTS FOR THE LIQUID-PHASE OXIDATION OF ORGANIC COMPOUNDS WITH MOLECULAR OXYGEN

Abstract

The transformation of organic compounds into oxygen-containing products such as epoxides, alcohols, ketones, and carboxylic acids plays an important role in the production of both bulk and fine chemicals. In this work, titanium-incorporated mesoporous silica (Ti-MCM-41) catalysts were synthesized via a direct hydrothermal approach and evaluated for their performance in liquid-phase oxidation reactions using environmentally friendly oxidants, particularly molecular oxygen. The influence of key synthesis parameters, including titanium loading, surfactant-to-silicon ratio, and template removal conditions, was systematically investigated in relation to the structural and catalytic properties of the materials. A variety of characterization techniques was employed to examine the physicochemical properties of the catalysts, with particular emphasis on the coordination environment of Ti(IV) species within the silica framework. The results revealed that both the dispersion and local coordination of titanium centers play a crucial role in determining catalytic activity, selectivity, and stability. The prepared catalysts exhibited efficient performance in selective oxidation reactions, highlighting the advantages of isolated active sites that combine features of both homogeneous and heterogeneous catalysis. Overall, this study contributes to the development of more efficient and sustainable catalytic systems for liquid-phase oxidation processes and provides important insights into the rational design of single-site catalysts based on mesoporous materials.