On the synthesis of LaCl3 catalysts for oxidative chlorination of methane

LaCl3 is an active and selective catalyst for oxidative chlorination of methane to methyl chloride, generated in situ by chlorination from LaOCl. The latter is prepared by precipitation of La(OH)2Cl and subsequent calcination. The synthesis route was modified by using different bases in order to synthesize high surface area LaOCl catalyst precursors. Ammonium hydroxide and the organic bases tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide are used as precipitating agents. The marked increase of the specific surface area by using organic bases indicates also that they may act as templating agents. After chlorination the specific surface areas of pure LaOCl samples decrease drastically, lanthanum carbonate, however, acts as structural promoter stabilizing the specific surface area during chlorination.