Pd和甲醛对Ag/C催化四氯化碳原位液相加氢脱氯性能的影响  

Effect of Pd and Formaldehyde on In-Situ Liquid Phase Catalytic Hydrodechlorination of CCl_4 Over Ag/C Catalysts

作　　者：周秀莲[1] 鲁墨弘[1] 朱劼[1] 李明时[1] 单玉华[1] 朱建军[1] 

机构地区：[1]常州大学石油化工学院,江苏常州213164

出　　处：《石油学报（石油加工）》2013年第2期269-276,共8页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金(20976076);江苏高校优势学科建设工程;化工资源有效利用国家重点实验室(CRE-2011-C-106);常州市应用基础研究计划项目(CJ20115004)资助

摘　　要：采用100mL反应釜,在N2存在条件下,研究了Ag/C催化剂催化CCl4液相原位加氢脱氯反应,考察了助催化剂Pd以及助剂甲醛溶液对CCl4原位催化转化反应转化率和产物选择性的影响,并结合XRD、XPS表征技术分析了甲醛自身分解反应。结果表明,助催化剂Pd可以提高Ag/C催化剂的活性,以n(Pd)/n(Ag)为0.03的Pd-Ag/C催化剂的活性最高;但对产物CH2Cl2和CHCl3的选择性没有影响,二者选择性之比仍维持在6/4。甲醛的加入明显提高Ag/C催化剂上CCl4的转化率,同时也改变了产物分布;反应4h,CCl4转化率和CH2Cl2选择性均达到90%。甲醛主要起促进Ag/C催化剂表面Ag-Cl物种还原为Ag的作用。In-situ liquid phase catalytic hydrodechlorination of CCl4 over Ag/C catalysts was studied. The effects of Pd and formaldehyde on the catalytic performance were investigated in a 100 mL autoclave with the presence of N2.The decomposition reaction of formaldehyde combined with the analysis of XRD and XPS was also carried out.The results showed that Pd promoted the activity of Ag/C. The Pd-Ag/C catalyst with Pd/Ag molar ratio of 0.03 exhibited high catalytic activity in the conversion reaction of CCl4. Selectivity of CH2Cl2 and CHCl3 was not influenced by the addition of Pd. Parallel reaction products CH2Cl2 and CHCl3 with a molar ratio of 6/4 were obtained in the catalytic dechlorination of CCl4 over Pd-Ag/C in methanol solution. The conversion of CCl4 catalytic conversion reaction over Ag/C increased and the distribution of product was changed when formaldehyde was added into the reaction system as promoter. Both the conversion of CCl4 and selectivity of CH2Cl2 were up to 90% after 4 h reaction. Formaldehyde played an important role in promoting the transformation of surface Ag-Cl species to active Ag.

关 键 词：四氯化碳(CCl4) 原位加氢脱氯 AG C催化剂 PD 甲醛 

分 类 号：O643[理学—物理化学]