Phase Cooperation between Tin and Antimony Oxides in Selective Oxidation of Isobutene to Methacrolein

L. T. WENG; P. PATRONO; E. SHAM; P. RUIZ; B. DELMON

JOURNAL OF CATALYSIS

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 1991 vol. 132 p. 360 - 374

0021-9517

A series of Sb-Sn mixed oxides prepared by coprecipitation and calcined at high temperature (900°C) has been studied in the selective oxidation of isobutene to methacrolein. The catalytic properties of these samples depend strongly on the Sb content. The physico-chemical characterization using XRD, BET, electron microscopy (CTEM, SEM, and AEM), and XPS has shown that these samples are composed almost exclusively of a SbxSnt-xO2 solid solution and pure antimony oxide (Sb204). A strong catalytic synergy was observed when a Sb-poor coprecipitate was mixed with either a pure ot-Sb204 or a Sb-rich coprecipitate. Physico-chemical characterization did not indicate any mutual contamination or the occurrence of solid state reaction. The catalytic performances of both pure coprecipitates and mechanical mixtures can be explained by a remote control mechanism, i.e., the fact that Sb204 produces spillover oxygen that can create or regenerate the selective catalytic sites of the SbxSn l_xO2 solid solution by reacting with its surface.