**9.2 Production of biodiesel via acylglycerols route**

Another approach reported in the literature consists on esterification of FFA with glycerol to form acylglycerols, followed by conventional transesterification. Synthesis of MAG from deodorizer distillate was mainly studied due to the large number of applications as additives (e.g. enhancing plasticity of fats) in the food, medicine and cosmetic industry. Among synthesized acylglycerols, the monoester has the highest surface activity and therefore, its concentration is very important for direct utilization of the reaction mixture as emulsifier.

Although the use of a large number of different heterogeneous catalysts have been reported in literature, most of the research has been done on the synthetic samples and less on the side stream refining products. Different studies summarized hereunder describe processes for synthesis of acylglycerols as an intermediate step in the production of biodiesel/biofuels. These processes are catalyzed either chemically or enzymatically, or conducted under noncatalytic conditions.
