Effects of Temperature, Concentration of Catalyst and Reaction Time

Gossipium hirsutum (cotton) seeds were collected and processed. 500.00 g of the processed cotton seeds were subjected to soxhlet extraction for 5 hours at 85^oC using absolute methanol (as extracting solvent). The extract (cotton seed oil) was recovered from extracting solvent by rotary evaporation and conce^ontrated to a constant weight at 37^oC. A solution mixture of volume ratio, 1: 9 of cotton seed oil to methanol was prepared and subjected to transesterification reaction under different operational conditions of temperature, concentration of catalyst (KOH) and reaction time for biodiesel production. The biodiesel produced was separated from the associated product (glycerol). The excess methanol containing biodiesel produced was removed by distillation. The saponification value of the glycerol component of the transesterification product was determined. The work showed that the optimum operational conditions for maximum biodiesel production were 65^oC, 1.00 M of KOH (as catalyst) and 65 minute. The work also showed that: temperature above 65^oC led to decomposition of biodiesel; catalyst concentrations above 1.00 M led to formation of soap as by-product and; prolonging of reaction time beyond 65 minute led to hydrolysis of the biodiesel formed.

Keywords: Gossipium hirsutum seed oil; transesterification reaction; biodiesel; glycerol; saponification value.