氟两相体系与甲苯硝化反应

Fluorous Biphase System and Nitration of Toluene

研究了氟溶剂和有机溶剂组成的氟两相体系、等当量的甲苯和硝酸的硝化反应。考察了硝化体系、反应时间和温度、氟溶剂的用量对硝基甲苯收率和产物异构体比例(Rp-/o-)的影响。全氟己烯(PFH)和全氟壬烯(PFN)可以和乙醚、正庚烷、四氯化碳和甲苯等有机溶剂形成氟两相体系,其互溶温度与组成有关。甲苯在全氟己烯中硝化的较佳工艺条件:n甲苯:n硝酸:n硫酸:nPFH=1:1:0.2:2.0,50℃反应4 h收率93.8%,Rp-/o-为0.66。冷却反应物料氟溶剂自动分层,分离简便,可循环使用。

Fluorous biphase system（FBS） formed by organic solvents and perfluorous nonene （PFN） or perfluorous hexane （PFH） and toluene nitration were investigated. The effects of nitration system, reaction time and temperature, perfluorous solvent on yield and ratio ofp-nitrotoluene to o-nitrotoluene（Rp＋/o＋） were studied. PFN or PFH forms binary FBS with ethyl ether, tetrachloromethanc, n-heptane and toluene respectively. The critical mutual soluble temperature depends on the contents of FBS. The yield is 93.8% and Rp-/o- is 0.66 in toluene nitration or ntoluene ： nHNO3 ： nH2SO4 ： nPFH = 1 ： 1 ： 0.2 ： 2.0 at 50 ℃ for 4 h. The perfluorous solvents can be recovered by simple phase separation and reused.