Optimization of Cotton Seed Methyl Ester and Mustard Methyl Ester from Transesterification Process

The most commonly used method for biodiesel preparation is via transesterification of vegetable oil using alkaline catalysts. Biodiesel yield and oil conversion are affected by operating conditions including the catalyst formulation and concentration. Application of alkaline catalysts can also lead to undesired soap formation. This study evaluated the alkaline catalyst effects on biodiesel yield and soap formation in transesterifying methanol with waste cotton seed oil and waste mustard oil at different catalyst concentrations. It was observed that methoxide catalysts led to better biodiesel yields. The methoxide catalysts not only accelerated the reaction but also elevated the conversion equilibrium. Based on experimental optimization, the operating conditions for maximizing cotton seed and mustard biodiesel yield and minimizing soap formation were potassium methoxide as catalyst at 1.5% (1.365 gm) for cotton seed biodiesel and 1.5% (1.305 gm) for mustard biodiesel, reaction temperature of 600C, and methanol-to-oil molar ratio of 5:1 for both the oils. Experimental verification gave 78.9% biodiesel yield from waste cotton seed oil and 87.9% biodiesel yield from waste mustard oil.