Hexane to Hexanol Oxidation with Metal-Organic Frameworks in the Light of Alkane to Alcohol Conversion

Abstract

This thesis investigates the oxidation of hexane to hexanol using metal-organic frameworks (MOFs) as catalysts, with hydrogen peroxide as the oxidizing agent. The study focuses on MIL-100, HKUST-1, and MOF-808 @His-Cu, examining their structural, thermal, and catalytic properties. Nitrogen adsorption-desorption isotherms and XRD analyses reveal distinct pore structures and crystallinity levels, which significantly influence their performance. MIL-100 and HKUST-1 exhibit mesoporous characteristics, while MOF-808 @His-Cu shows slit-shaped mesopores. XRD results indicate that MIL-100 is synthesized with high purity and relatively high crystallinity, HKUST-1 has a minor impurity, and MOF-808 @His-Cu shows signs of impurities or incomplete synthesis.

The SEM images reveal distinct morphologies: MIL-100 displays porous polyhedral grains, HKUST-1 exhibits smooth octahedral crystals, and MOF-808 @His-Cu shows precise octahedral crystals, confirming their crystalline nature. Thermogravimetric analysis (TGA) demonstrates that MIL-100 has the highest thermal stability, followed by HKUST-1 and MOF-808 @His-Cu. Under inert conditions, MIL-100 decomposes at higher temperatures than the other MOFs, reflecting its greater stability.

Experimental results indicate that increasing temperature and reaction time enhance hexane conversion, though selectivity decreases with temperature but improves with longer reaction times. Varying pressure does not significantly affect conversion or selectivity, and the presence of MOFs significantly boosts both conversion and selectivity compared to reactions without MOFs.

Among the studied MOFs, MIL-100 offers lower conversion but higher selectivity compared to HKUST-1, while MOF-808 @His-Cu exhibits both lower conversion and selectivity. These findings underscore the importance of MOF properties in optimizing hexane oxidation processes and provide valuable insights for their application in industrial catalysis.