Lanthanum oxide-based catalysts are active in the elimination of HCl from C 2 H 5 Cl, 1,2-C 2 H 4 Cl 2 and 1,1,2-C 2 H 3 Cl 3 leading to the formation of their respective chlorinated ethenes. An oxygen-rich catalytic surface may form CO, CO 2 and C 2 HCl as side products, whereas with chlorine-rich catalytic surfaces a stable product distribution is achieved with 100% selectivity towards the formation of ethenes, such as the valuable C 2 H 3 Cl intermediate.