Transesterification of non-edible castor oil (Ricinus communis L.) from Mexico for biodiesel production: a physicochemical characterization

Biodiesel is an alternative fuel that has been used to replace petroleum diesel and to generate a positive impact on the economy and the environment. The aim of this paper was at identifying the variety of castor oil plant that could be cultivated and harnessed as bioenergy crops in Tlaltenango (Zacatecas, Mexico). Different varieties of wild castor (Ricinus communis L.) were studied, obtaining oil from its seeds and producing biodiesel from the variety with higher oil content by transesterification reaction at laboratory scale. Both oil and biodiesel were characterized physicochemically, and biodiesel quality was evaluated and compared with biofuels standards ASTM-D6751 (USA) and EN-14214 (European Union). Three varieties were identified; the denominated "green stem with wax, ashen fruit" showed the highest oil content (51.7 +/- 5.6%), presenting a yield of the transesterification reaction of 61.44 +/- 0.44%. The produced biodiesel complies with recommended value by both standards, except for the viscosity and the moisture, so its use is only suggested in blends with petroleum diesel. In conclusion, the variety "green stem with wax, ashen fruit" has the basic physicochemical characteristics for being considered an option in the industrial production of biodiesel in this city, being safe to use it in diesel engines.