Silica-Supported Boron Phosphate Catalyst Prepared by Chemical Vapor Deposition

Abstract

Abstract A silica-supported boron phosphate (BPO4) catalyst was prepared by chemical vapor deposition (CVD) using mixtures of boron triethoxide and phosphoryl trimethoxide. Both the amount and the P/B ratio of deposited BPO4 were changed with the CVD temperature and time. At the optimum CVD temperature of 300°C, the amount of deposited BPO4 was linearly increased with the CVD time. When alkoxide mixtures with the desired P/B ratio were used as CVD sources at 300°C, the expected P/B ratios were available. At CVD temperatures below 300°C, neither a sufficient amount nor a desired P/B ratio was given. On the other hand, above 325°C, the deposition was suppressed by blocking the micropore of silica, especially for long-time CVD operation, owing to the too fast deposition. Although the resulting surface compound was amorphous, it was revealed to have microstructures of BPO4 by means of a 31P NMR measurement. The amorphous BPO4 dispersed highly on silica exhibited a high catalytic efficiency for the isomerization of 1-butene and a simultaneous oligomerization of 1-butane in comparison with a catalyst prepared by the conventional impregnation method.