The organometallic complex ≡Si-O-Zr(CH2C(CH 3)3)3 was synthesized on the surface of silica dehydroxylated at 500 °C and its reactivity towards oxygenated molecules was studied. The materials were characterized by IR, 13C CP-MAS NMR, analysis of evolved gases and elemental analysis. Reaction with neopentyl alcohol ((CH3)3CCH2OH) leads to the quantitative formation of ≡Si-O-Zr(OCH2C(CH3) 3)3. Similarly, reaction with pivalic acid ((CH 3)3CCOOH) leads to the quantitative formation of ≡Si-O-Zr(OCOC(CH3)3)3. Addition of dry oxygen at 25 °C to ≡Si-O-Zr(CH2C(CH3) 3)3 leads to the formation of ≡Si-O-Zr(OCH 2C(CH3)3)3. When heated at 200 °C under oxygen, the alkoxy ligands transform into carboxylate species ((CH3)3CCOO)- probably coordinated to zirconium. These results, together with molecular modelling studies of the adsorption of hydrocarbons on mordenite modified by such complexes, explain the different behaviours observed in presence of air or inert gases.
- Solid-state NMR
ASJC Scopus subject areas
- Process Chemistry and Technology
- Physical and Theoretical Chemistry