CuCl2/Al2O3 ethylene oxychlorination catalysts have been characterized by using IR spectroscopy of the surface hydroxy-groups and of adsorbed pyridine and CO2. The ethylene oxychlorination reaction to 1,2-dichloroethane has been investigated by using pulse reactor studies and in-situ IR experiments in static conditions. The results allowed emphasizing the negative role of uncovered alumina surface, evidenced by IR experiments, considered to be responsible for the dehydrochlorination of 1,2-dichloroethane with a consequent loss in selectivity that is very important in low Cu-loading samples.