¹Department of Chemical engineering, Dr B.R. Ambedkar National Institute of Technology, Jalandhar Punjab India

²Indian Oil Corporation Limited (R&D Centre), Faridabad Haryana India

Email:-gerapoonam@gmail.com

Biodiesel, a renewable energy source seems to be an ideal solution for global energy demands. The main advantages of biodiesel include its domestic origin, potential for reducing a given economy's dependency on imported petroleum, biodegradability, high flash point, and inherent lubricity. The current review is addressed to the application of various heterogeneous catalysts for biodiesel production. Heterogeneous catalysts are environmentally benign, non-corrosive, easily separated from the liquid products; give higher activity, selectivity and longer catalyst lifetime. However a high molar ratio of alcohol to oil, large amount of catalyst and high temperature and pressure are required while utilizing heterogeneous catalysts to produce biodiesel. Transesterification using CaO as solid catalyst and other basic alkaline earth metal compounds like Calcium methoxide and Barium hydroxide with different edible and non-edible oils has been studied. Different kinds of metal oxides containing Calcium, Barium, Magnesium, or Lanthanum have been used as catalysts. CaMnO₃, Ca₂Fe₂O_5, CaZrO₃, CaCeO₃ and CaTiO₃ whose catalytic basicities were the highest, showed higher yields of ester. The catalysts with low basicities BaTiO₃, BaZrO₃, BaCeO₃, MgTiO₃, MgZrO₃, MgCeO₃, LaZrO₃, and LaCeO₃ ester yields were 1% or less and little activity was observed. Alumina supported heterogeneous catalysts KNO3/Al₂O_3, KI/Al₂O_3, Na/NaOH/g-Al₂O₃ were used for the production of biodiesel from soybean oil. NaX zeolite loaded with 10% KOH followed by heating gave promising results as heterogeneous catalyst. A heterogeneous catalyzed process needs to be optimized, considering the effect of relevant process parameters like temperature, residence time, methanol to oil ratio etc. in order to improve biodiesel yield and properties.The diminishing petroleum reserves and growing environmental concerns have made renewable fuels an exceptionally attractive alternative as the fuel for the future.