烷基氟化物消除氟化氢反应的取代基效应-2  

Theoretical Study on the Substituent Effect of the Elimination of Hydrogen Fluoride from Ethyl Fluoride-2

作　　者：李庆明[1] 方德彩[2] 傅孝愿 

机构地区：[1]北京师范大学化学系 [2]北京师范大学化学系 北京 100875 [3]北京 100875

出　　处：《物理化学学报》1994年第1期12-14,共3页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金

摘　　要：实验发现卤代烷既可以发生1-1消除卤化氢的反应也可以发生1-2消除卤化氢的反应。究竟那种消除反应占优势,主要由取代基团决定,我们曾对氟代烷烃1-2热消除反应的取代基效应进行了研究。本文对氟代烷1-1热消除氟化氢反应取代基效应进行研究。反应式为式中R₁,R₂,R₃为取代基,所研究的几个反应物分别为 （1）R₁=R₂=R₃=H;（2）R₁=F,R₂=R₃=H;（3）R₁=R₂=H,R₃=F; （4）R₁=CH₃,R₂=R₃=H;（5）R₁=R₂=H,R₃=CH₃;（6）R₁=R₂=H,R₃=CN; （7）R₁=CN,R₂=R₃=H;（8）R₁=R₃=H,R₂=NH₂;（9）R₁=R₂=H,R₃=NH₂The substituent effect of the 1-1 elimination reaction of hydrogen fluoride from ethyl fluoride have been studied by ab initio method at the HF/3-21G level. The reactants are CH_3CH_2F, CH_3CHF_2, CH_2FCH_2F, CH_3CH_2CH_2F, CH_3CHFCH_3, CH_3CHFCN, CH_2CNCH_2F, CH_2NH_2CH_2F, CH_3CHFNH_2 and their reaction barriers are 369.5,433.5,306.9,365.6,357.3,354.1,383.2,370.3,250.3kJ.mo1^(-1) respectively. It can be concluded that the 1-1 elimination reaction of CH3_CHFNH_2 is the easiest to proceed. This conclusion can be rationalized by its characteristic transition state geometry.

关 键 词：烷基氟化物 氟化氢 取代基效应 

分 类 号：O623.21[理学—有机化学]