果胶对钯的吸附及其在有机合成中的应用  

Adsorption of Palladium by Pectin and Its Application in Organic Synthesis

作　　者：周宇[1] 何媛[1] 周文俊[1] 

机构地区：[1]内江师范学院化学化工学院,四川内江641112

出　　处：《应用化学》2015年第12期1402-1409,共8页Chinese Journal of Applied Chemistry

基　　金：四川省教育厅培育项目(12ZZ012);青年基金项目(11ZB074);内江师范学院博士科研启动费(2012B05)资助项目~~

摘　　要：以果胶为吸附剂,研究其对钯(Ⅱ)的吸附性能,探讨了溶液的p H值、吸附温度、果胶用量、吸附时间及钯(Ⅱ)溶液的初始浓度对吸附量的影响。采用Pseudo-First-order、Pseudo-Second-order、Intraparticle、Diffusion、Langmuir、Freundlich和Temkin等模型对实验数据进行线性拟合。结果表明,果胶对钯(Ⅱ)有很强的吸附性能,吸附率高达96%以上,溶液的最佳p H值为6.5,最佳温度为50℃,果胶对钯的吸附量随果胶用量的增加而降低,随钯溶液初始浓度的增加而增加。吸附动力学遵从Pseudo-Second-order模型,即以化学吸附为主;等温吸附过程符合Freundlich方程;吉布斯自由能为负值,焓变和熵变分别为3.23 k J/mol和13.32 J/(mol·K),即该过程是自发吸热的;果胶吸附的钯作为催化剂应用到Suzuki反应中,结果表明该催化剂有较高的催化活性。The adsorption of palladium from aqueous solution by pectin was studied. The effect of solution pH value, temperature, pectin dosage, contact time and initial concentration of palladium solution on the adsorption was investigated. The kinetics data were analyzed by the Pseudo-First-order, Pseudo-Second-order and Intraparticle Diffusion models. The equilibrium data were simulated using Langmuir, Freundlich, and Temkin isothermal equations. The results show that pectin has good adsorption ability and the adsorption ratio is as high as 96%. With the best pH of 6.5 and the best temperature of 50 ℃, the adsorption capacity decreases with the increase of the pectin dosage, while it increases as the initial concentration of palladium solution increases. The adsorption kinetics of palladium obeys the Pseudo-Second-order model to show that this is a chemical adsorption. The isotherm adsorption is fitted in the Freundlich equation. Gibbs free energy is negative, the enthalpy change is 3.23 kJ/mol and the entropy change is 13.32 J/（mol·K）, showing that it is a spontaneous endothermic process. The adsorbed palladium was used as the catalyst for Suzuki reaction with a good catalytic activity.

关 键 词：果胶 钯 吸附 SUZUKI反应 

分 类 号：O629.9[理学—有机化学]