Preparation and Characterization of Metal Soaps of Cocos nucifera Seed Oil

Abstract

This study investigated the extraction of Cocos nucifera seed oil (CSO) from Cocos nucifera seed using aqueous processing and the production of metal soaps from the oil and their characterization in terms of colour, pH, free caustic alkalinity, foaming power, foam stability, and corrosion inhibition test. The metal soaps of the oil produced by metathesis were soaps of nickel, calcium, barium, zinc, iron and magnesium. The results of tests of the metal soaps showed that Ni-CSO was greenish in colour, Zn-CSO, Mg-CSO, Ba-CSO and Ca-CSO were white and Fe-CSO had a dark-brown colour. The pH of the metal soaps varied between 6.5 to 8.2. The free caustic alkalinity was low and varied between 0.30 % to 0.43 %. Foam stability was in the order Fe-CSO 0.80, Ca-CSO 0.81, Zn-CSO 0.86, Ni-CSO 0.90, Mg-CSO 0.92 and Ba-CSO 0.93. For corrosion inhibition test Ni-CSO at 100 mg/L, Ca-CSO at 60 mg/L, Mg-CSO, Ba-CSO and Fe-CSO at 40 mg/L inhibited tiger head razor blade corrosion while the other concentrations of the metal soaps showed varied degrees of corrosion.

Keywords: Cocos nucifera seed oil; metal soaps; corrosion inhibition; foam stability