(CaO‐Y₂O₃)@LiFe₅O₈ magnetic catalyst by doping yttrium for improving stability: Optimized by response surface methodology for biodiesel production

Abstract

In this work, CaO@LiFe 5 O 8 and (CaO-Y 2 O 3 )@LiFe 5 O 8 solid base catalysts were synthesized using LiFe 5 O 8 as the magnetic core to support the active centers. The as-prepared catalysts and commercial CaO were characterized using X-ray diffraction, scanning electronic microscope, and CO 2 -temperatureprogrammed desorption techniques. The results indicated that CaO@LiFe 5 O 8 and (CaO-Y 2 O 3 )@LiFe 5 O 8 solid base catalysts, which could be recycled under the external magnetic field because of their strong magnetism, exhibited better dispersibility and higher total number of basic sites compared with commercial CaO. Additional water and oleic acid were added to the reaction system of palm oil with methanol, and the catalyst was exposed to air to detect its stability in the reaction process. The experiments showed that the (CaO-Y 2 O 3 ) @LiFe 5 O 8 solid base catalyst performed better and possessed not only good water resistance ability but also preferable tolerance to air exposure. In addition, response surface methodology based on the Box-Behnken design was used to optimize the process parameters for the synthesis of biodiesel from palm oil and methanol in the presence of (CaO-Y 2 O 3 )@LiFe 5 O 8 . The optimum process conditions were determined as follows: reaction temperature was 64.96 C, reaction time 4.36 hr, methanol: oil 13, catalyst amount 3.73%, and the highest biodiesel yield reached 96.21%. K E Y W O R D Sbase catalyst, biodiesel, magnetism, response surface methodology, transesterification

Study of Thermodynamics and Experiment on Direct Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol over Yttrium Oxide

“…The isolated O 2− could supply electrons and act as basic sites in the synthesis process. 31,32 From Table S3, we can witness that the Y 2 O 3 -750 catalyst owned the most adsorbed oxygen and O 2− compared with other catalysts, which may largely facilitate the activation of CO 2 and CH 3 OH. Considering the XPS and NH 3 /CO 2 -TPD reports in the literature, 25,29 the concentrations of the moderate basic and acidic sites were essentially related to those of the isolated O 2− and adsorbed oxygen, respectively, which was in reasonable agreement with our experimental and characterization results.…”

Response surface methodology optimization of supramolecular dispersive liquid‐liquid microextraction‐solidified floating organic drop of brilliant green and its spectrophotometric determination

“…The significance of each parameter was evaluated through the sum of squares, the F value (Fisher test), and the corresponding p-value. At 95% confidence level, a p value less than 0.05 indicates that the null hypothesis of equal variances (comparing the mean square of the parameter and the mean square of the error) is rejected and the variable effect is statistically significant, [40] F value reveals the importance of the corresponding component. [41] The significance of the quadratic equation is also determined by the values of R 2 and R 2 adj , the closeness of these values to one indicates the high correlation between the experimental and the predicted results.…”

Zirconia‐coated magnetic Fe2O3 nanoparticles supported 12‐tungstophosphoric acid: A novel environmentally friendly catalyst for biodiesel production

“…Along with the gradual depletion of traditional fossil resources, there has been growing interest in the development of alternative renewable fuels that are easily available and environmentally friendly, for example, biodiesel. [ 1–4 ] Traditionally, biodiesel refers to fatty acid methyl or ethyl ester produced through the (trans)esterification [ 5 ] process of low‐cost raw materials such as waste cooking oil, [ 6 ] jatropha seeds, [ 7 ] palm fatty acid, [ 8 ] and distillate [ 9 ] with methanol or ethanol using acid/alkaline catalysts. [ 10 ] These raw materials contain a high level of free fatty acids (FFAs) resulting in a saponification problem with a homogeneous basic catalyst.…”