Continuous Production of Fine TiO₂Powders by Vapor-Phase Hydrolysis of Titanium Tetraisopropoxide

Submicrometer, highly porous (BET area <320 m{sup 2}/g) TiO{sub 2} powders were synthesized by vapor-phase hydrolysis of titanium tetraisopropoxide, Ti(OPr{sup i}){sub 4}, in a tubular-flow reactor under atmospheric pressure at 443 to 783 K. Particle size increased with increasing inlet Ti(OPr{sup i}){sub 4} concentration and with decreasing inlet H{sub 2}O concentration and temperature. It is suggested that particle formation and growth occurred in a very short residence time in the reactor. Almost all of the Ti(OPr{sup i}){sub 4} could be converted to TiO{sub 2} powder with negligible deposition inside the reactor, indicating the high efficiency of the process.