Thermolytic Conversion of a bis(alkoxy)tris(siloxy)tantalum(V)Single-Source Molecular Precursor to Catalytic Tantala-SilicaMaterials
The new complex ({sup i}PrO){sub 2}Ta[OSi(O{sup t}Bu){sub 3}]{sub 3} (1) was prepared via silanolysis of Ta(O{sup i}Pr){sub 5} with ({sup t}BuO){sub 3}SiOH and is a useful structural and spectroscopic (NMR, FTIR) model of Ta(V) on silica. The complex was also used to prepare tantalum-containing silica materials, via the thermolytic molecular precursor method (yielding Ta{sub 2}O{sub 5}{center_dot}6SiO{sub 2} and Ta{sub 2}O{sub 5}{center_dot}18SiO{sub 2}) or by grafting 1 onto mesoporous SBA-15 silica (yielding a surface-supported tantala species, TaSBA-15). The solution phase thermolysis of 1 in nonpolar media afforded homogeneous, high-surface-area (ca. 450 m{sup 2} g{sup -1}) xerogels (Ta{sub 2}O{sub 5}{center_dot}6SiO{sub 2}) that are amorphous up to approximately 1100 C. A more silica-rich tantala-silica material (Ta{sub 2}O{sub 5}{center_dot}18SiO{sub 2}) was prepared via a solution-phase co-thermolytic route with 1 and HOSi(O{sup t}Bu){sub 3}, to yield a material with a Si/Ta ratio of 9/1. It was demonstrated that tantala-silica materials are active as catalysts for cyclohexene oxidation.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Basic EnergySciences
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 919913
- Report Number(s):
- LBNL-57108; JCTLA5; R&D Project: 401701; BnR: KC0302010; TRN: US200822%%600
- Journal Information:
- Journal of Catalysis, Vol. 229; Related Information: Journal Publication Date: 2005; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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