CAJ | 학술논문

利用同位素取代法考察了[Bmim]Br-AlCl_3催化苯与1-十二烯烃烷基化反应机理.首先进行了[Bmim]Br-AlCl_3催化氘代苯与1-十二烯烃的反应,通过GC-MS及NMR分析产物十二烷基苯同分异构体的结构,验证了氘原子与产物侧链1-位碳相连的结论.示踪氘原子推导了烷基化反应机理,结果表明:[Bmim]Br-AlCl_3催化苯与长链烯烃的烷基化反应是由[Al_2Cl_6Br]~-发生平衡移动,生成Lewis酸AlCl_3引发的;AlCl_3吸电子作用使l-十二烯烃的π电子向1-碳转移,在烯烃的2-碳上形成正电荷中心,碳正离子与苯发生亲电反应生成不稳定的σ络合物,与σ络合物环上的σ-C相连的D~+转移到负电的侧链1-C上形成C-D键,AlCl_3离去,生成产物2-十二烷基苯.Lewis酸催化机理为离子液体催化苯与长链烯烃的反应中,2-十二烷基苯选择性高于H质子催化产物提供了理论依据.
이용동위소취대법고찰료[Bmim]Br-AlCl_3최화분여1-십이희경완기화반응궤리.수선진행료[Bmim]Br-AlCl_3최화도대분여1-십이희경적반응,통과GC-MS급NMR분석산물십이완기분동분이구체적결구,험증료도원자여산물측련1-위탄상련적결론.시종도원자추도료완기화반응궤리,결과표명:[Bmim]Br-AlCl_3최화분여장련희경적완기화반응시유[Al_2Cl_6Br]~-발생평형이동,생성Lewis산AlCl_3인발적;AlCl_3흡전자작용사l-십이희경적π전자향1-탄전이,재희경적2-탄상형성정전하중심,탄정리자여분발생친전반응생성불은정적σ락합물,여σ락합물배상적σ-C상련적D~+전이도부전적측련1-C상형성C-D건,AlCl_3리거,생성산물2-십이완기분.Lewis산최화궤리위리자액체최화분여장련희경적반응중,2-십이완기분선택성고우H질자최화산물제공료이론의거.
Alkylation mechanism of benzene with 1-dodecene in [Bmim]Br-AlCl_3 was investigated. Alkylation of C_6D_6 with 1-dodecene using [Bmim]Br-ALCl_3 as a catalyst was firstly carried out. Molecular structures of products, dodecylbenzene isomers, were analyzed by GC-MS and NMR, and the deuterated atom in the dodecylbenzenes was verified to be connected with 1-carbon of the side chain. Alkylation mechanism was deduced by tracing the deuterated atom. Results demonstrated that alkylation was induced by AlCl_3, which was generated by the dissociation of [Al_2Cl_6Br]~-. The role of AlCl_3 in attracting electrons pushs π electrons to 1-carbon of 1-dodecene, and the positive center is formed at 2-carbon. The carbonium ion reacts with benzene to form a σ complex, which is instable and D~+ connected to the σ carbon of ring is transferred into electronegative 1-C of the side chain to form a C-D bond, accordingly AlCl_3 leaves. 2-Dodecylbenzene is formed. The Lewis acid mechanism provides the evidences for the higher selectivity of 2-dodecylbenzene using ionic liquid as catalyst than that using H~+ as catalyst.