Chlorination of titanias modified by alkali and/or phosphorus additives

Abstract

The kinetics of the chlorination of titania modified by alkali and/or phosphorous additives, were studied by thermogravimetric methods using COCl₂ and gaseous CCl₄ as chlorinating agents. The chlorination of pure titania was compared with that of phosphorous-containing compounds, TiO₂ · nP₂O₅ and K₃P₃O₉ were also investigated. Apparent activation energies and reaction orders were calculated from the dependence of the initial rates on temperature and partial pressure.

With COCl₂ as chlorinating agent and increased alkali content of the samples resulted in an increase in the reaction rate, whereas the phosphorous additive behaved as a retardant, and their inhibiting effects became more and more pronounced in the course of the reaction. On the other hand when chlorinating with CCl₄, high amounts of K or Na additives retarded the reaction, and Li enhanced the chlorination.