Sol-gel entrapped cobalt complex

Journal Article · Sat Mar 15 04:00:00 EST 2003 · Materials Characterization

DOI:https://doi.org/10.1016/S1044-5803(03)00074-3· OSTI ID:20748685

Lima, Omar J. de; Papacidero, Andrea T; Rocha, Lucas A; Sacco, Herica C; Nassar, Eduardo J; Ciuffi, Katia J; Bueno, Luciano A; Messaddeq, Younes; Ribeiro, Sidney J L

This work describes optimized conditions for preparation of a cobalt complex entrapped in alumina amorphous materials in the form of powder. The hybrid materials, CoNHG, were obtained by a nonhydrolytic sol-gel route through condensation of aluminum chloride with diisopropylether in the presence of cobalt chloride. The materials were calcined at various temperatures. The presence of cobalt entrapped in the alumina matrix is confirmed by ultraviolet visible spectroscopy. The materials have been characterized by X-ray diffraction (XRD), surface area analysis, thermogravimetric analysis (TGA), differential thermal analyses (DTA) and transmission electron microscopy (TEM). The prepared alumina matrix materials are amorphous, even after heat treatment up to 750 deg. C. The XRD, TGA/DTA and TEM data support the increase of sample crystallization with increasing temperature. The specific surface area, pore size and pore diameter changed as a function of the heat treatment temperature employed. Different heat treatment temperatures result in materials with different compositions and structures, and influence their catalytic activity. The entrapped cobalt materials calcined at 750 deg. C efficiently catalyzed the epoxidation of (Z)-cyclooctene using iodozylbenzene as the oxygen donor.

• OSTI ID: 20748685
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 2-3 Vol. 50; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AFTER-HEAT
ALUMINIUM CHLORIDES
ALUMINIUM OXIDES
COBALT
COBALT CHLORIDES
COBALT COMPLEXES
CRYSTALLIZATION
DIFFERENTIAL THERMAL ANALYSIS
HEAT TREATMENTS
MATRIX MATERIALS
OXYGEN
POWDERS
SOL-GEL PROCESS
SPECIFIC SURFACE AREA
SURFACE AREA
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY
ULTRAVIOLET RADIATION
X-RAY DIFFRACTION