高分子负载铁催化剂的制备及其甲苯选择性氯化反应性能  

Preparation and application of a polymer-supported iron catalyst for selective chlorination of toluene

作　　者：王跃华[1] 李婷婷[1] 任开路 葛裕华[1] 

机构地区：[1]东南大学化学化工学院,江苏南京211189

出　　处：《工业催化》2015年第8期609-613,共5页Industrial Catalysis

基　　金：江苏省产学研联合创新资金-前瞻性联合研究项目(SBY201320102)

摘　　要：通过金属铁离子与高分子载体进行螯合反应,制备高分子负载铁催化剂,用原子吸收光谱法测定催化剂中Fe3+含量,并利用傅里叶变换红外光谱仪、扫描电子显微镜、热重分析对制备的催化剂分子结构、微球形貌和热稳定性进行表征,并研究有机硫助催化剂的添加对高分子负载铁催化剂催化甲苯选择性氯化性能的影响。结果表明,铁离子与乙酰丙酮基的两个氧原子形成了六元螯合环的强相互作用,使Cl2分子更易极化,提高了催化反应速率;有机硫助催化剂不仅改变Cl—Cl键的强度,而且增大了亲电试剂的空间位阻,从而显著提高对位选择性和稳定性。1%(占甲苯的质量分数)高分子负载铁催化剂/0.05%(占甲苯的质量分数)有机硫助催化剂催化甲苯选择性氯化反应表现出最佳的催化性能,氯化反应2 h,甲苯转化率超过90%,对氯甲苯选择性55.74%,多氯甲苯质量分数低于1%。催化剂可重复使用。A polymer-supported iron catalyst （YCH2CHAcAc-Fe3＋ ） was prepared by chelation reaction of Fe3 ＋ and polymer support. The molecular structure, microsphere morphology and thermal stability of the as-prepared catalyst was characterized by fourier transform infrared spectrometer, scanning electron micro- scope and thermogravimetric analysis, and its iron content was determined by atomic absorption spectrom- etry. The effects of sulfur-containing cocatalyst （OS） on the catalytic properties of polymer-supported iron catalyst （YCH2CHAcAc-Fe3＋） for the selective chlorination of toluene were investigated. The results showed that iron ions formed a chelated six-member ring with two oxygen atoms of acetylacetone, and C12 molecules were easier to be polarized due to the strong interaction between iron ions and oxygen atoms, so the chlorination rates was improved;sulfur-containing cocatalyst （OS） not only changed the bond strength of C1--C1, but also increased the steric hindrance of electrophilic reagent, which greatly improved the catalytic selectivity and stability. YCH2CHAcAc-Fe3＋ catalyst （ 1% of toluene mass） with sulfur-containing cocatalyst （0.05% of toluene mass） exhibited the best catalytic performance under the condition of room temperature and chlorination reaction time 2 h and could be recycled. Toluene conversion and the selec- tivity to p-chlorotoluene reached over 90% and 55.74%, respectively, and the mass fraction of byproduct multi-chlorotoluene was controlled less than 1%.

关 键 词：催化化学 高分子 螯合反应 负载催化剂 选择性氯化 回收利用 

分 类 号：O643.26[理学—物理化学] TQ426.6[理学—化学]