Jie Zhu,Tongxin Qu,Shengli Niu,Jisen Liu,Sitong Liu,Jie Geng,Zihao Yang,Abulikemu Abulizi
The development of reusable heterogeneous catalysts with acid-base bifunctions employing low-cost oil as a raw material is critical for optimizing the biodiesel synthesis process. In the present study, Sr–La/wollastonite bifunctional catalysts with the different Sr/La atomic ratios are synthesized using a straightforward impregnation technique. The results show that the Sr 7 La 3 /wollastonite catalyst establishes a biodiesel yield of 95.35% upon initial use and 85.14% after the fifth cycle of reuse, under the transesterification conditions of a catalyst content of 8 wt.%, methanol to oil molar ratio of 15, reaction duration of 3 h, and reaction temperature of 150 °C. The biodiesel yield of 91.62% is obtained even after the addition of 5 wt.% oleic acid, and the catalyst maintains a high biodiesel yield (>80%) for three reused cycles, which illustrates the good resistance to free fatty acids (FFAs). Meanwhile, the process parameters for transesterification are optimized utilizing Response Surface Methodology combined with Box-Behnken Design (RSM-BBD). With a methanol to oil molar ratio of 17.7 and a catalyst content of 6.4 wt.%, biodiesel yield is 96.08% at 149 °C for 3 h. This study revealed the enormous potential of the Sr–La/wollastonite bifunctional catalyst in biodiesel production.
A solid acid catalyst KLC-SO3H bearing SO3H, COOH and phenolic OH groups was synthesized by the sulfonation of industrial waste kraft kraft lignin-based activated carbon (KLC) which was prepared from phosphoric acid (PA) activation. The KLC support and the catalyst
were characterized by a variety of techniques. The prepared catalyst exhibits good activity to catalyze the esterification of oleic acid with methanol. Yield of methyl oleate as high as 93.2% was obtained under the temperature of 80 °C, methanol to oleic acid molar ratio of 10:1, reaction
time of 12 h and catalyst loading of 10% (based on oleic acid). The prepared KLC-SO3H catalyst showed similar catalytic activity with the carbon acid catalyst from cellulose and the commercial catalyst Amberlyst-15 in the esterification reaction. The high catalytic activity of KLC-SO3H
was probably due to the large specific surface area, pore volume of KLC support, which provided more acid sites for the reactants.
Yilin Ning,Shengli Niu,Yongzheng Wang,Jianli Zhao,Chunmei Lu
This work reported the one-pot synthesis of the promising, cheap and green heterogeneous nanocatalyst for biodiesel production . The halloysite nanotube (HNT) was impregnated with 40 wt % NaAlO 2 (SA) and the assistance of ultrasonic helped to achieve a better and more stable modification. The resulting 0.4SA/HNTs-UI catalyst was applied in catalyzing the transesterification of palm oil with methanol, using a GA_BP neural network to train and predict the optimal values of reaction parameters. The test results proved the prediction accuracy of the model with R 2 = 0.989. The catalyst possessed excellent performance, and the maximum biodiesel yield of 99.15% was achieved with the catalyst loaded amount of 8.82 wt %, methanol to oil molar ratio of 16.79 and transesterification temperature of 65.12 °C. Besides, the physicochemical properties of the purified transesterification product were in accordance with the ASTM D 6751 standard of biodiesel .
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