Studies On Supported Rare Earth Metals Solid Base Preparation And Its Catalysis Performance In Transesterification

At present,biomass energy and chemicals can play an important role in coping with the depletion of fossil energy,energy conservation and emission reduction,and national strategic energy reserve.Biodiesel is biodegradable,renewable,lightning fast,non-toxic and can be mixed with fossil fuels and other advantages.In general,biodiesel is synthesized by transesterification with homogeneous acid or base catalyst.However,because homogeneous acid or alkali catalyst is easy to corrode the equipment and not easy to separate from the product and other disadvantages,in recent years,people have been exploring and trying to use solid alkali catalyst for the preparation of biodiesel.In addition,with the severe shortage of fossil fuels,it is urgent to develop the technology of biodiesel preparation,in which catalysts for transesterification play an important role.The main research contents of this paper are as follows:?1?In this paper,hydrothermal method was used to prepare catalyst carrier ZrO2-CeO2,and KF was introduced into the catalyst by impregnation method to improve the basicity of the catalyst.The final catalyst was used for transesterification reaction to synthesize biodiesel.XRD,N2 adsorption-desorption,FT-IR,CO2-TPD,TEM-EDS and Raman were used to characterize the physical and chemical properties of catalysts of catalyst.The results showed that the introduction of ZrO₂ into CeO₂could improve the thermal stability of the catalyst carrier and provide more oxygen holes.The introduction of KF on ZrO2-CeO2 supports can improve the overall basicity of the catalyst.In best condition for the KF load of 15 wt.%?relative to the soybean oil?,calcination temperature is 400?,alcohol oil ratio systematically,catalyst for 5 wt.%?relative to the soybean oil?,the reaction temperature is 65?,the reaction time of 5 h of soybean oil with methanol transesterification preparation of biodiesel yield up to 99.8%.?2?In this paper,the catalyst carrier MgO-CeO₂ was prepared by co-precipitation method,and then the base strength of the catalyst was improved by impregnation method.The final catalyst was used for transesterification reaction to synthesize biodiesel.In the process of roasting,lattice defects occur in the process of MgO crystal destruction,and KF and MgO interact with each other to generate a new strong alkali species KMgF₃,therefore,providing a strong alkali catalytic activity center.XRD,N2 adsorption-desorption,TG-DTA,SEM,CO2-TPD,TEM and Raman were used to test and characterize the prepared catalyst.It can be known that the catalyst presented spherical shape,which will be conducive to improve the specific surface area of the catalyst and make the raw material have a larger contact area with the alkaline active site.In the best conditions for the KF load of 12.5 wt.%?relative to the soybean oil?,calcination temperature is 400?,alcohol oil ratio of 25:1,catalyst for5 wt.%?relative to the soybean oil?,the reaction temperature is 65?,reaction time is 6 h of soybean oil with methanol transesterification preparation of biodiesel yield up to 99.8%.