【作者】 陈静；

【导师】 丁立军；

【作者基本信息】 内蒙古农业大学 ， 农业资源应用化学， 2022， 硕士

【摘要】 生物柴油作为一种生物可降解、可再生、绿色环保的理想矿石燃料替代品,受到各国重视。课题组之前的研究证明,杭锦2^#土可以有效地提高SO₄^2-/M_xO_y型固体酸催化剂的比表面积,用于生物柴油（BD）的转酯化反应。然而,如何合理调控金属中心和配体之间的相互作用进而提高催化活性和选择性,一直是该类催化剂催化转酯化反应所面临的巨大挑战。本研究分别以La、Ce为助催化剂制备了SO₄^2-/ZrO₂-La₂O₃-杭锦2^#土（SZLa-HJ）、SO₄^2-/ZrO₂-Ce O₂-杭锦2^#土（SZCe-HJ）两种催化剂,NH₃-TPD、Py-FTIR等表征结果表明,引入La、Ce可调节SO₄^2-/ZrO₂--杭锦2^#土（SZ-HJ）的酸度分布,增加Bronsted和Lewis酸位的数量,并将催化剂更多的保持在Lewis酸位以促进转酯化反应的发生。利用稀土修饰粘土基催化剂制备生物柴油,对于提高稀土在催化剂改性方面的应用具有重要意义,也为学者研发生物柴油提供了参考。主要内容和研究成果总结如下:1.本文采用沉淀浸渍法制备了SZLa-HJ、SZCe-HJ两种催化剂,采用CCD（Central Composite Design）实验设计法对稀土用量、硫酸浓度、焙烧温度三因素进行分析、拟合,得到了数学模型。经优化后SZCe-HJ的制备条件:稀土Ce掺杂量为6.17wt.%,硫酸浓度1.57mol/L,焙烧温度为344℃,此时BD平均转化率为36.18%;优化后SZLa-HJ的制备条件:稀土La掺杂量为3.7wt.%,硫酸浓度为1.69mol/L,焙烧温度为357℃,此时BD平均转化率为28.77%。2.对SZCe-HJ、SZLa-HJ催化剂催化制备生物柴油进行活性评价,结果表明在同一条件下,催化活性:SZCe-HJ>SZLa-HJ,选定SZCe-HJ为最优催化剂,用于后续生物柴油的制备工艺研究。同时采用SEM、BET、XRD、XPS、NH₃-TPD、Py-FTIR等多种表征方法对催化剂的晶相、热分解性能、孔结构、表面酸度及酸类型等进行表征。3.基于单因素结果,采用CCD实验设计优化了SZCe-HJ催化大豆油基生物柴油的制备工艺,结果表明最佳工艺参数为:醇油摩尔比30:1,催化剂用量3.06wt%,反应温度178℃,反应时间6h,此时BD平均转化率最高可达62.92%。此外发现催化剂稳定性良好,通过进一步对催化剂催化性能进行比较,发现生物柴油转化率:SZCe-HJ>SZLa-HJ>SZ-Ti（Contrast）>SZ（Contrast）>SZ-HJ,这进一步证明本文对催化剂的改性是成功的。更多还原

【Abstract】 As an ideal substitute for biodegradable,renewable,and green fossil fuels,biodiesel has been paid attention to by many countries.The previous studies of the research group have proved that Hangjin2^#clay can effectively increase the specific surface area of SO₄^2-/M_xO_ysolid acid catalyst for the transesterification of biodiesel（BD）.However,how to rationally regulate the interaction between metal centers and ligands to improve the catalytic activity and selectivity has always been a great challenge for this kind of catalyst.In this study,two kinds of catalysts,SO₄^2-/ZrO₂-La₂O₃-Hangjin2^#clay（SZLa-HJ）and SO₄^2-/ZrO₂-Ce O₂-Hangjin2^#clay（SZCe-HJ）,were prepared with La and Ce as cocatalysts,respectively.NH₃-TPD,Py-FTIR,and other characterization results show that the introduction of La and Ce can adjust the acidity distribution of SO₄^2-/ZrO₂-Hangjin2^#clay（SZ-HJ）,increase the number of Bronsted and Lewis acid sites,and keep more catalysts in Lewis acid sites to promote the occurrence of transesterification.The preparation of biodiesel using a rare-earth-modified clay-based catalyst is of great significance to improve the application of rare earth in catalyst modification,and also provides a reference for scholars to develop biodiesel.The main contents and research results are summarized as follows:1.SZLa-HJ and SZCe-HJ catalysts were prepared by the precipitation impregnation method.The three factors of rare earth dosage,sulfuric acid concentration,and calcination temperature were analyzed and fitted by CCD（Central Composite Design）experimental design method,and the mathematical model was obtained.After optimization,the preparation conditions of SZCe-HJ are as follows:the amount of rare earth Ce doping is 6.17wt.%,the concentration of sulfuric acid is 1.57mol/L,and the calcination temperature is 344℃.The average coversion rate of BD is 36.18%.The preparation conditions of SZLa-HJ:the amount of rare earth La doping is 3.7wt%,the concentration of sulfuric acid is 1.69 mol/L,and the calcination temperature is 357℃,and the average conversion rate of BD is 28.77%.2.The activity of SZCe-HJ and SZLa-HJ catalysts for biodiesel production was evaluated.The results showed that under the same conditions,the catalytic activity was:SZCe-HJ>SZLa-HJ,and SZCe-HJ was selected as the best catalyst to be used in the subsequent research on the biodiesel production process.At the same time,SEM,BET,XRD,XPS,NH₃-TPD,Py-FTIR and other characterization methods were used to characterize the crystal phase,thermal decomposition performance,pore structure,surface acidity and acid type of the catalyst.3.Based on the single factor results,the preparation process of soybean oil-based biodiesel catalyzed by SZCe-HJ was optimized by CCD experimental design.The results showed that the optimum process parameters were as follows:the molar ratio of alcohol to oil was 30:1,the amount of catalyst was 3.06wt%,and the reaction time was 178℃for6h.At this time,the average conversion rate of BD could reach 62.92%.In addition,it is found that the catalyst has good stability.By further comparing the catalytic performance of the catalyst,it is found that the conversion rate of biodiesel is SZCe-HJ>SZLa-HJ>SZ-Ti（contrast）>SZ（contrast）>SZ-HJ,which further proves the subject’s modification of the catalyst was successful.更多还原