Preparation Of Solid Acid Catalyst By Modification Of Hangjin2~# Clay And Preparation Of Biodiesel

In this experiment,the SO₄^2-/ZrO₂-Hangjin 2^#clay solid acid catalyst was prepared by co-precipitation-impregnation method to catalyze the preparation of biodiesel from soybean oil using Hangjin2#clay produced in Hangjin Banner of Ordos City as raw material,and the activity of the catalyst system was evaluated in terms of biodiesel yield,and the catalyst was characterized by various methods to study the catalyst preparation The catalysts were characterized by various methods,and the property changes and stability of the catalysts during the preparation process were studied.The experimental results showed that.1.SZ-HJ-2^#solid acid catalyst was prepared by co-precipitation-impregnation method and used to catalyze the transesterification reaction between soybean oil and methanol,and the composition of the product was proved to contain fatty acid methyl ester by GC-MS,thus proving that SZ-HJ-2^#solid acid catalyst has transesterification reaction activity.The best preparation conditions were:the concentration of zirconium solution was0.5 mol/L,the concentration of sulfuric acid impregnating solution was 1.5 mol/L,and the roasting temperature was 450℃,and the biodiesel yield was 89.61%.3.The XPS,XRD,FT-IR,SEM,EDS,BET,ICP-MS,NH₃-TPD and TG characterization of SZ-HJ-2^#solid acid catalyst and intermediate products showed that both sulfuric acid activation and loaded Zr could effectively increase the specific surface area;the Zr-OH produced during co-precipitation would be converted to Zr-O by pre-roasting;the loaded Zr Zr-O-Si bonding helps to enhance the acid strength of the catalyst;the loading of sulfuric acid will cause the leaching of Zr;the catalytic activity is better when the roasting temperature reaches 450°C,although the catalyst structure will collapse.4.Combining the experimental results of single factor,the BBD experimental design method was used to optimize the catalytic transesterification reaction of soybean oil with methanol by SZ-HJ-2^#.The mathematical model was obtained by fitting and analyzing the experimental results;the optimized optimal biodiesel production conditions were:the reaction temperature was 56℃,the molar ratio of alcohol to oil was 8.14:1,the catalyst dosage（mass fraction of catalyst to vegetable oil used）was 2.51 wt%,and the reaction time was 9 h.The highest biodiesel yield of 95.46%was obtained under this condition,which was similar to the predicted value（94.74%）;after ANOVA and significance analysis,the order of the influence of the factors on the experimental results was determined as:catalyst dosage（wt%）>reaction temperature>alcohol-oil molar ratio>reaction time.The catalyst was subjected to repeated catalytic transesterification reactions,and the results showed that the stability of the catalyst was poor,and only 26.7%of the transesterification activity remained after four times of repeated use,and the deactivation was attributed to the obvious loss of sulfur elements and carbon accumulation by characterization analysis.