| abstract |
In its most general aspect, the present invention relates to the use of fatty substances having a iodine number greater than 135 gI2/l00g, preferably greater than 140 gI2/l00g, more preferably greater than 150 gI2/l00g, for the production of biodiesel . In particular, the invention relates to a method for the production of biodiesel starting from fatty substances having a iodine number greater than 135 gI2/l00g, preferably greater than 140 gI2/l00g, more preferably greater than 150 gI2/l00g, comprising the following steps: a) esterification of the fatty acids or transesterification of the triglycerides present in the aforementioned fatty substances with a Ci-Ci0 alkyl alcohol, optionally in the presence of a suitable catalyst; b) the selective hydrogenation of the fatty acid alkyl esters obtained in step a) in the presence of a catalyst allowing the attainment of a biodiesel with a degree of unsaturation (evaluated as the iodine number) less than or equal to 120 gI2/l00 g and which is liquid at temperatures greater than or equal to -200C. Between step a) and step b) there may also optionally be a step al) for the separation of the fatty acid alkyl esters obtained in step a) from the non-esterified resin acids. |