二、取代基对芳环亲电取代反应的影响 A study of the chemistry of aromatic compounds leads to/deeper understanding of the effects of electronic and/ steric factors on reactivity, which will be of benefit in the further study of chemistry and biochemistry
二、取代基对芳环亲电取代反应的影响 A study of the chemistry of aromatic compounds leads to deeper understanding of the effects of electronic and steric factors on reactivity, which will be of benefit in the further study of chemistry and biochemistry
二、取代基对芳环亲电取代反应的影响 1. Experimental Facts CH. 3 c CH3 HNO NO2 3 Faster than nitration of bezene no. 2 ortho para- Br Br Br HNO3 NO 2 Slower than nitration of bezene NO 2 ortho- para- NO 2 NO 2 Slower than HNO meta- nitration of bezene NO
二、取代基对芳环亲电取代反应的影响 1. Experimental Facts: CH 3 HNO 3 CH 3 NO 2 CH 3 NO 2 ortho- paraFaster than nitration of bezene Br HNO 3 Br NO 2 Br NO 2 ortho- paraSlower than nitration of bezene NO 2 HNO 3 NO 2 Slower than nitration of bezene NO 2 meta-
二、取代基对芳环亲电取代反应的影响 2. The effect of substituents on reactivity ① Activating substituents(致活基 Electron-donating/ substituents/(给电子基 increase the reactivity of the benzene ring toward electrophilic aromatic substitution ② Deactivating substituents(致钝基) Electron-withdrawing substituents(吸电子 4t)decrease the reactivity of the benzene ring toward electrophilic aromatic substitution
二、取代基对芳环亲电取代反应的影响 2. The effect of substituents on reactivity ① Activating substituents (致活基 ) —— Electron-donating substituents (给电子基) increase the reactivity of the benzene ring toward electrophilic aromatic substitution. ② Deactivating substituents (致钝基 ) —— Electron-withdrawing substituents (吸电子 基) decrease the reactivity of the benzene ring toward electrophilic aromatic substitution
二、取代基对芳环亲电取代反应的影响 2. The effect of substituents on reactivity relative rates of electrophilic substitution Z donates electrons Y withdraws electrons into the benzene ring from the benzene ring
二、取代基对芳环亲电取代反应的影响 2. The effect of substituents on reactivity
二、取代基对芳环亲电取代反应的影响 ● Relative reactivity: Strongly activating substituents 致活基{ Moderately activating substituents Weakly activating substituents 取决于取代基电子效应对苯环电子云密度影响的大小 Weakly Activating Substituents 致钝基{ Moderately activating Substituents Strongly activating substituents
二、取代基对芳环亲电取代反应的影响 z Relative reactivity: 致活基 致钝基 取决于取代基电子效应对苯环电子云密度影响的大小 Strongly activating substituents Moderately activating substituents Weakly activating substituents Weakly Activating Substituents Moderately activating Substituents Strongly activating substituents