Aminolysis of triglycerides using nanocrystalline nickel doped CaO as an efficient solid catalyst

Abstract

The present manuscript reports the preparation of Ni doped CaO in nanocrystalline form, using a wet chemical method, and the investigation of their catalytic activity towards aminolysis of a variety of triglycerides with diethanolamine. The powder XRD study suggested the formation of a solid solution of NiO in CaO as long as the nickel content in the catalyst remained ≤5 wt%. A transmission electron microscopy study supported the formation of Ni/CaO particles in the form of nanorods at a 650 °C calcination temperature. Catalyst activity was found to be a function of basic strength which in turn depends upon the catalyst calcination temperature. The catalyst prepared by 0.5 wt% Ni doping in CaO at 650 °C was found to complete the aminolysis (>99% amide yield) of waste cottonseed oil within 0.5 and 3.0 h at 110 °C and room temperature (35 °C), respectively. The catalyst was easily recovered from the reaction mixture by simple filtration and reused during seven consecutive reaction cycles without a significant loss in activity. The (pseudo) first order rate constant and activation energy for the reaction was observed as 0.15 min⁻¹ and 52.7 kJ mol⁻¹, respectively.