Hydrothermal Conversion Of Fatty Acids Into Fatty Alcohols And Hydrocarbons

A Large amount of fossil energy is consumed excessively with the rapid growth of the world economy,which will threaten the development of human society due to fossil energy's non-renewab ility.Therefore,looking for the new renewab le and green energy sources which can replace the fossil energy is urgent.Over the past several decades,biomass has attracted more and more attention to be used to produce high value-added chemicals and alleviate the pressure from excessive consumption of fossil fuels due to its excellent properties,such as abundance,renewab ility,and less pollution.Natural oils and fats,as one of the most potential biomass resources,are complex mixtures of glycerides,which consist of a glycerol backbone with three fatty acid moieties.The fatty acids can serve as feedstocks for the production of fatty alcohols and renewable liquid transportation fuels,such as biodiesel and green diesel(e.g.,hydrocarbons).The current catalytic hydrogenation method for the synthesis of fatty alcohols or hydrocarbons from fatty acids still has some limitations,such as the use of gaseous hydrogen,organic solvents and expensive catalysts.Therefore,the development of a suitable reaction process for the production of fatty alcohols or hydrocarbons from fatty acids is highly desirable.In this study,the synthesis of fatty alcohols from fatty acids using water as hydrogen source in the presence of metals under hydrothermal conditions is investigated.This research provides a useful process for the synthesis of fatty alcohols with the advantages of more simpleness,higher yield and less pollution,without the use of high-pressure gaseous hydrogen,expensive catalysts and organic solvents.On the other hand,the hydrothermal convers ion of fatty acids into fatty hydrocarbons using relatively cheap metals as catslysts is also investigated.This synthetic procedure of fatty hydrocarbons lowers the reaction costs.Initially,the conversion of fatty acids into fatty alcohols under hydrothermal conditions with palmitic acid as a model compound was investigated.The reaction conditions such as the kinds of catalysts and reductants,reaction time and temperature,water filling were optimized.The yield of 81.4% hexadecanol was obtained with the addition of 5.0 mmol Zn,1.0 mmol Ni,40% water filling at 300 ? for 2 h.This result provides a useful method for the production of fatty alcohols from fatty acids under hydrothermal conditions.Next,based on previous experimental results,reaction pathway for the fatty alcohols production from fatty acids under hydrothermal conditions was proposed.Finally,experiments of palmitic acid,as a model compound of fatty acids,with different metal catalysts under hydrothermal conditions were conducted to screen the optimal catalyst to produce fatty hydrocarbons from fatty acids.We finally chose Ru/C as the optimal catalyst and the highest pentadecane yield of 43.6% was obtained with 0.2 mmol palmitic acid,0.02 mmol Ru/C and 50% water filling at 325 ? for 2 h.