Design Of Magnetic Calcium Base Solid Alkali And Its Catalytic Transesterification Synthesis Of Biodiesel

As a kind of new biomass energy, biodiesel is environmental friendly and renewable. Compared with the traditional alkaline catalysts, magnetic solid alkali catalyst not only solve the problem of separation from products and wastewater, but also have some advantages such as no corrosion of equipment, high catalytic activity and reusability. In this work, four kinds of new solid base catalysts were successfully synthesized and characterized, and they were applied to biodiesel production by transesterification to research their catalytic activity.According to the synergy between calcium and magnesium, which could improve the catalytic activity of calcium oxide, CaO@MgFe2O4 catalysts using MgFe2O4 as magnetic core were investigated. The obtained heterogeneous catalyst was highly efficient for the synthesis of biodiesel with soybean oil and methanol as raw material. Furthermore, under the reaction conditions of catalyst dosage 1.0 wt.%, methanol and soybean oil ratio of 12:1, reaction temperature of 70 oC, reaction time of 3 h, the CaO@MgFe2O4 catalyst showed the better activity, the higher acid-resistance and the better water resistance in the transesterification reaction compared with pure CaO. The excellent performance of CaO@MgFe2O4 catalyst with the yield of biodiesel 98.3% could be mainly attributed to the synergy between calcium and magnesium. Moreover, the catalyst simply recovered by an external conventional magnet and recycled after completion of reaction, and there was no significant decrease of the catalytic activity. After further reused 5 times, the yield of FAME could still reach 89.7%, which indicated that the CaO@MgFe2O4 catalyst had a prefect stability and recyclability.The Ca-Mg mixed oxides were synthetized from a new method by using calcium oxalate and magnesium oxalate as the precursors for transesterification of soybean oil. The analysis results showed that the catalyst with neat blocky structure had better water-resistance compared to the pure calcium oxide. And the CaO-MgO exhibited higher amounts of basic site and provided higher catalytic activity in the methanol activation process. The highest biodiesel yield reached 98.4% over CaO/MgO with a Ca-to-Mg molar ratio of 1:3 under the optimal reaction conditions: 1.0 wt.% of catalyst adding, 12:1 of methanol/oil and reacting at 70 oC for 2 h. Hopefully, this kind of stable solid base catalyst could confirm the yield of FAME still above 90.0% after using 5 times which demonstrated the good reusability of mixed oxide CaO-MgO catalyst.A kind of magnetic solid base catalyst was prepared by using CaO-MgO as active component and CoFe2O4 as magnetic nuclear, which was applied to synthesize the biodiesel in transesterification reaction as solid base catalyst. The solid base catalyst was characterized through magnetic hysteresis loop, X-ray diffraction(XRD), CO2-TPD and transmission electron microscopy(TEM). The different core-shell mole ratio, calcination temperature, reaction temperature, reaction time, mole ratio of methanol oil and the amount of catalyst on the soybean oil conversion were evaluated. The results showed that the biodiesel yield could reach to 98.1% when the core-shell mole ratio was 1:6, calcination temperature was 700 oC, reaction temperature was 65 oC, reaction time was 3 h, oil and methanol mole ratio was 12:1 and the amount of catalyst on the soybean oil was 1.0 wt.%. The recycle of catalyst was investigated. The result showed that the biodiesel yield still above 90.0% after being used four times.A novel solid base catalyst CaO parcel strontium ferrite with magnetism used for the production of clean biodiesel was prepared and characterized by X-ray diffraction, transmission electron microscope, infraredspectrum magnetism analysis and CO2-TPD. The catalytic activities of the fresh and the reused catalysts for the transesterification of soybean oil with methanol to produce biodiesel were investigated. The catalyst was similar to the shell-core form by transmission electron microscopy images. The yield of biodiesel was 94.9% under the conditions of catalyst dosage(catalyst/oil) of 0.5 wt.%, 70 oC for2 h, methanol/oil molratio of 12:1.