湖南科技大学学报（自然科学版）
湖南科技大學學報（自然科學版）
호남과기대학학보（자연과학판）
JOURNAL OF HUNAN UNIVERSITY OF SCIENCE & TECHNOLOGY（NATURAL SCIENCE EDITION）
2014年
4期
98-103
,共6页
羧酸酯%亲核取代%反应速率%定量结构-性质相关
羧痠酯%親覈取代%反應速率%定量結構-性質相關
최산지%친핵취대%반응속솔%정량결구-성질상관
carboxylic ester%nucleophilic substitution%reaction rate%quantitative structure -property relationship
羧酸酯的亲核取代反应速率受羧酸酯的离去基团（LG）、非离去基团（NLG）和亲核试剂（Nu）结构的影响。从文献整理了大量结构多样的羧酸酯与各种亲核试剂发生亲核取代反应的表观二级速率常数kN，基于亲核取代反应机理，用非离去基团的极化效应指数PEI（NLG）和基团体积参数GVI（NLG），亲核试剂与离去基团的体积参数之比GVI（Nu）／GVI （LG），以及亲核试剂与离去基团共轭酸的pKa 之差（pKa （Nu）－pKa （LG））分别表征非离去基团、离去基团和亲核试剂的结构特征及亲核试剂与离去基团的相互竞争，并用上述参数对73组亲核取代反应的logkN建立多元线性回归模型，得到较好的结果。该模型所用参数简便，物理意义明确，为从分子结构特征定量估算羧酸酯亲核取代反应的速率提供了理论依据。
羧痠酯的親覈取代反應速率受羧痠酯的離去基糰（LG）、非離去基糰（NLG）和親覈試劑（Nu）結構的影響。從文獻整理瞭大量結構多樣的羧痠酯與各種親覈試劑髮生親覈取代反應的錶觀二級速率常數kN，基于親覈取代反應機理，用非離去基糰的極化效應指數PEI（NLG）和基糰體積參數GVI（NLG），親覈試劑與離去基糰的體積參數之比GVI（Nu）／GVI （LG），以及親覈試劑與離去基糰共軛痠的pKa 之差（pKa （Nu）－pKa （LG））分彆錶徵非離去基糰、離去基糰和親覈試劑的結構特徵及親覈試劑與離去基糰的相互競爭，併用上述參數對73組親覈取代反應的logkN建立多元線性迴歸模型，得到較好的結果。該模型所用參數簡便，物理意義明確，為從分子結構特徵定量估算羧痠酯親覈取代反應的速率提供瞭理論依據。
최산지적친핵취대반응속솔수최산지적리거기단（LG）、비리거기단（NLG）화친핵시제（Nu）결구적영향。종문헌정리료대량결구다양적최산지여각충친핵시제발생친핵취대반응적표관이급속솔상수kN，기우친핵취대반응궤리，용비리거기단적겁화효응지수PEI（NLG）화기단체적삼수GVI（NLG），친핵시제여리거기단적체적삼수지비GVI（Nu）／GVI （LG），이급친핵시제여리거기단공액산적pKa 지차（pKa （Nu）－pKa （LG））분별표정비리거기단、리거기단화친핵시제적결구특정급친핵시제여리거기단적상호경쟁，병용상술삼수대73조친핵취대반응적logkN건립다원선성회귀모형，득도교호적결과。해모형소용삼수간편，물리의의명학，위종분자결구특정정량고산최산지친핵취대반응적속솔제공료이론의거。
The nucleophilic substitution reaction rate of carboxylic ester is influenced by the structures of leaving group (LG),non-leaving group (NLG)of carboxylic ester and the nucleophile (Nu).A large number of apparent second -order rate constants (kN)were colletcd and analyzed,which of nucleophilic substitution reactions between structurally diverse carboxylic esters and a variety of nucleophiles.Based on the mechanism of nucleophilic substitution reaction,the polarizability effect index PEI(NLG)and group volume index GVI(NLG) of non-leaving group,the ratio of group volume index of nucleophile to that of the leaving group GVI(Nu)/GVI (LG),the difference between pKa of the conjugate acid of nucleophile and that of leaving group (pKa (Nu)-pKa(LG)),were employed to characterize the structures of non-leaving group,leaving group and nucleophile. logkN of 73 nucleophilic substitution reactions were correlated to the structural descriptors mentioned above,and multiple linear regression model was established with good performances.The parameters used in the model were simple and had clear physical meanings.This study provided a theoretical basis for quantitatively estimating the nucleophilic substitution reaction rate of carboxylic esters from molecular structures.
