EFFECT OF LYE SOURCE ON THE KINETICS AND QUALITY OF LOCAL SOAP

This research presents the effect of lye on the kinetics and quality of local soaps. To achieve this, 40ml of 10 percent lye (palm bunch, coconut shell and synthetic sodium hydroxide) reacted with 60ml of oil (palm oil and palm kernel oil) in a batch system, under conditions as, constant temperature (50 degree celcius) and constant stirring (100 rpm). Variation in saponification value and free fatty acid was monitored with time, that is, at intervals of 2mins. It was noticed that as time increases the values of both saponification and free fatty acid reduced. The reaction kinetics was studied using the integral method. MATLAB R2009b was used for evaluating the integral method employed and was also used for graphs plotting and developing the order of reaction and rate constant. Result using MATLAB R2009b showed that the six soaps were all first order for both the variation in saponification value and free fatty acid. Although the rate constant for both saponification and free fatty acid were different for the soaps. For variation in saponification value, the rate constant (k) for NaOH and palm kernel oil soap: 0.076sec-i, for NaOH and palm oil soap: 0.076sec-i, for palm bunch and palm oil soap 0.06sec-i, for palm bunch and palm kernel oil soap: 0.073sec-i, for coconut shell and palm kernel oil soap: 0.033sec-i, for coconut shell and palm oil soap: 0.073sec-i. For variation in free fatty acid, the rate constant (k) for NaOH and palm kernel oil soap: 0.30sec-i for NaOH and palm oil soap: 0.25sec-i, for palm bunch and palm oil soap: 0.14sec-i, for palm bunch and palm kernel oil soap: 0.22sec-i, for coconut shell and palm kernel oil soap: 0.160sec-i, for coconut shell and palm oil soap: 0.31sec-i .The reaction rate was substantially influenced by the concentration of lye which was evident at the beginning of the reaction. The lye from palm bunch and coconut shell for soap making was extracted by local method, sodium and potassium content for palm bunch is 8.5455ppm and 5.7820ppm and for coconut shell 6.2494ppm and 3.9860ppm respectively. Saponification value of the oil was checked before the reaction, and was observed to be 171mgKOH/g for palm oil and 144.45mgKOH/g for palm kernel oil. Analysis of the local soap was done which was compared with the analysis of B29 soap and literature values. Conclusively, local soap made by reacting palm bunch, synthetic NaOH and coconut shell with palm oil and palm kernel oil is reliable.