Factors Affecting the Kinetics of Biodiesel Reactions

A study of factors affecting reaction kinetics of biodiesel production was continued by examining two variations on biodiesel reactions.  Composition of the reaction mixture was analyzed by NMR.  In one study, unreacted catalyst and excess methanol present in the waste glycerol layer from a previous reaction were used as the only source of catalyst and base.  This reaction was slow, reaching a conversion of approximately 10%.  Similar slow reaction rates were observed when the glycerol layers from two previous experiments were used to give a 6:1 methanol:triglyceride ratio.  The rate increased significantly when the reaction was run with one glycerol layer as well as half the fresh amount of methanol and methoxide used as the basis.  Previous work suggested that addition of isopropyl alcohol showed promise in increasing reaction rates.  When the reaction was run using fresh methanol and methoxide, but with the addition of 20 mL of isopropyl alcohol, both reaction rate and conversion increased.  Similar increases were observed when isopropyl alcohol was also added to the reaction mixture using recycled glycerol waste.  Further investigations to quantify these effects are planned.