论文部分内容阅读
一、定位规律苯的一元取代物所起的取代反应,根据大量实验事实归纳出来下面的定位规律: 1.在苯环上新导入取代基的位置主要由原有取代基来决定。 2.可以把取代基分为两类:第一类取代基使新导入的基进入邻位和对位,并且使取代反应易于进行(卤素例外);第二类取代基使新导入的取代基进入间位,并且使取代反应难于进行。属于第一类取代基有: OH,OR,OCOR,SH,SR,NH_2,NHR,NR_2, NHCOR,CH_3,
First, the positioning laws Benzene substitution reaction from the monobasic substitution, according to a large number of experimental facts summarized the following positioning rules: 1. In benzene ring on the introduction of new substituents mainly by the original substituents to decide. 2. Substituents can be divided into two groups: the first group of substituents introduces the newly introduced group into ortho and para positions and facilitates the substitution reaction (exception of halogens); the second group of substituents introduces newly introduced substituents Enter the meta position, and make the substitution reaction difficult to proceed. The first class of substituents are: OH, OR, OCOR, SH, SR, NH_2, NHR, NR_2, NHCOR, CH_3,