An evaluation of alkylthiols and dialkyl disulfides on deactivation of Cu/Zn catalyst in hydrogenation of dodecyl methyl ester to dodecanol

Deactivation of co-precipitated Cu/Zn catalyst caused by exposure to either alkylthiols or dialkyl disulfides in catalytic hydrogenation of dodecyl methyl ester to dodecanol is explored in a stirred batch reactor. Catalytic activity decrement is highly dependent on levels of poisons, types of thiols/disulfides, chain length of alkanes. XRD, EDS and XPS are employed to characterize the fresh and spent Cu/Zn catalysts. It is evident that sulfuric species prefer to attack zinc oxide, forming chemically adsorbed Zn-SR at low sulfur levels, and ZnS is formed in the highly reductive atmosphere before sulfuric species attacking copper (forming Cu7S4 or Cu31S16).