Dodecyl aldehyde is the intermediate in the one-step amination of dodecyl alcohol and dimethylamine (HNMe2) to the corresponding tertiary amine, N,N-dimethyldodecylamine (RNMe2). Carbon monoxide (CO) generated by the decarbonylation of dodecyl aldehyde, significantly poisons the Cu/Ni-based colloidal catalysts stabilized by barium stearate (Cu/Ni/Ba). Therefore, the prevention of CO generation or removal of CO from the reaction system was required to maintain the catalytic activity. A copper-based CO absorber was effective for removing CO, but the methanation of CO was not effective because of a significant decrease in activity of the Cu/Ni/Ba colloidal catalyst and a significant transalkylation of HNMez. The incorporation of a small amount of triphenylphosphite (P(OPh)(3)) with the Cu/Ni/Ba colloidal catalyst (Cu:Ni:Ba:P(OPh)(3) mole ratio = 5:1:1:0.16) caused a significant reduction in CO poisoning. Water was also a catalyst poison for the Cu/Ni/Ba colloidal catalyst, and cupric hydroxide significantly decreased the catalytic activity. (c) 2005 Elsevier B.V. All rights reserved.