Microwave Assisted Catalytic Transfer Hydrogenation Of Jatropha Oil Biodiesel By Raney-Ni

With the rapid development of the economy in this era,people's overall living standard have been continuously improved,and their demand for substances is also growing.To maintain the energy needed for economic development,the fossil energy in this world was excessively used,which caused irreparable situations.And the environmental problems caused by fossil energy are even more difficult to solve.Fortunately,the concept of sustainable development has gradually formed in human consciousness in recent decades,and the human has begun to develop clean reproducible energy.Biodiesel is a research hotspot of reproducible energy.Because of its good safety,combustion performance,and regeneration property,biodiesel as a green energy can become a replacement of fossil fuels,which would help reduce human dependence on fossil energy.Jatropha curcas is a woody plant with drought tolerance,which is easy to plant,and can grow quickly in difficult environments.Jatropha oil biodiesel was prepared using the low cost Jatropha oil.The main component of Jatropha oil biodiesel is fatty acid methyl ester(FAME),however,a large amount of polyunsaturated FAMEs causes poor antioxidant capacity of biodiesel,and the practical application for Jatropha oil biodiesel is still limited.Hence,it can improve the using performance of Jatropha oil biodiesel by hydrogenation.In this work,a systematic study on the catalytic transfer hydrogenation(CTH)reaction of microwave-assisted Jatropha oil biodiesel was conducted using low industrial cost Raney-Ni as catalyst,isopropanol as hydrogen donor,and water as solvent.Microwave was used into the CTH of biodiesel to avoid the harsh hydrogenation conditions of high temperature and high pressure.And then hydrogenation reaction can be processed under mild conditions.The process conditions were optimized under isothermal and non-isothermal conditions.And the influence of different process conditions on the biodiesel components of upgraded biodiesel was investigated.In addition,the effect of microwaves on the catalyst was explored.SEM,XRD,FTIR and thermogravimetric analysis were used to characterize the Raney-Ni catalyst before and after the reaction,and the reason of inactivation of Raney-Ni was discussed as well.Finally,the effects of different kinds of hydrogen donor on catalytic transfer hydrogenation(CTH)were investigated.And then combining with the GC-MS analysis of upgraded biodiesel,the reaction mechanism of microwave-assisted Raney-Ni catalytic transfer hydrogenation of Jatropha oil biodiesel was determined.The research results provide reference for the industrial utilization of Jatropha oil biodiesel.The main research results are as followed:(1)Under isothermal conditions,microwave was used to assist Raney-Ni of CTH.The components of upgraded biodiesel under different conditions were analyzed by gas chromatography,and the quantitative analysis was carried out by the rectified area normalization method.The optimum conditions were catalyst dosage 8 wt%,reaction temperature 85 ?,isopropyl alcohol amount 24 g,water amount 80 g,and stirring rate 400 rpm.The changes of biodiesel components with reaction time at different temperatures were investigated.The microwave-assisted CTH of Jatropha oil biodiesel by Raney-Ni can be well described by pseudo first-order kinetics.The model was learned and the kinetic parameters at different temperatures were obtained.Effective ways to hydrogenation of Jatropha oil biodiesel were that microwave as heat source,Raney-Ni as catalyst,water as solvent,and isopropyl alcohol as hydrogen donor.(2)Under the condition of equal microwave power,the optimum conditions for the microwave-assisted CTH of Jatropha oil biodiesel by Raney-Ni are catalyst dosage 12 wt%,microwave power 150 W,isopropyl alcohol amount 24 g,water amount 80 g,and stirring rate 200 rpm.The changes of biodiesel components with reaction time and reaction temperature under different microwave powers were investigated.It was found that the content of C18:2 in biodiesel was 2.74 wt.%at a microwave power of 150 W for 40 min,and the contents of C18:1 and C18:0 were 77.46 wt.%and 8.33 wt.%,respectively,at which point the upgraded biodiesel achieved a better performance.Non-isothermal kinetics were investigated and the kinetic parameters under different microwave powers were obtained.(3)The effect of microwave on the performance of Raney-Ni catalyst was investigated.It was found that higher temperature was unfavorable for the performance of Raney-Ni catalyst.Compared with the traditional heating,the microwave has inhibitory effect on the performance of Raney-Ni catalyst.Furthermore,the effects of different kinds of hydrogen donor on the microwave-assisted CTH were compared,and it was found that primary alcohol were inferior to secondary alcohol as hydrogen donor.And the tertiary alcohol was not suitable for CTH as a hydrogen donor.In addition,it was discovered that formic acid,sodium formate and ammonium formate all had no effect on CTH as the hydrogen donor.Therefore,secondary alcohol was selected as the hydrogen donor for microwave-assisted CTH of Jatropha oil biodiesel by Raney-Ni.Comparison of different secondary alcohols under microwave heating and under conventional heating,the results showed that microwave heating was more contributed to the reaction rate of C18:2 to C18:1,and the CTH had a higher C18:1 selectivity under microwave heating.The catalysts were characterized by SEM,XRD,FTIR and thermogravimetric analysis,which revealed the reason for the deactivation of Raney-Ni catalyst was the increase of the sediments on the catalyst surface after the reaction.Finally,the reaction mechanism of microwave-assisted CTH of Jatropha oil biodiesel by Raney-Ni was described by the six-membered ring transition state theory.