间甲基苯腈的硝化及产物的结构表征

Nitration of m-Tolunitrile and Identification of the Products

以浓硝酸为硝化剂硝化间甲基苯腈得到3种硝基间甲基苯腈的异构体.在n(间甲基苯腈):n(发烟硝酸)=1:10,反应时间2 h,反应温度18～20 ℃的条件下,冰浴中将浓硝酸缓慢滴加到间甲基苯腈中,得3种硝基间甲基苯腈异构体,粗品总收率92%.经柱层析和重结晶,从粗产物中分离出3种纯异构体,分别为3-甲基-4-硝基苯腈、3-甲基-6-硝基苯腈和3-甲基-2-硝基苯腈,以间甲基苯腈计,收率分别为43%、37%和12%.应用核磁共振、红外和气质联用技术,表征了3种纯异构体的结构,对硝化反应的位置选择性进行了初步分析.

Three nitro isomers of m-tolunitrile were obtained in 92% total yield via nitration of m-tolunitrile with concentrated nitric acid （ ≥ 98% ） under the following conditions ： n （ m-tolunitrile ） ： n （ nitric acid） = 1 ： 10, reaction time 2 h, reaction temperature 18 - 20 ℃ and dropping nitric acid to m-tolunitrile in ice bath. Column chromatography followed by recrystallization gave three pure isomers 5-cyano-2-nitrotoluene, 3-cyano-4-nitrotoluene and 3-cyano-2-nitrotoluene in 43%, 37% and 12% yield respectively, based on m-tolunitrile. Structure of the pure isomers was characterized by IR, ^1HNMR and GS/MS. Regioselectivity of the nitration was discussed.