论文部分内容阅读
共轭双键的性质比较活泼,在起加成反应时,主要生成1,4-加成产物,同时也生成1,2-加成产物。如丁二烯与溴化氢加成,其产物是1-溴-2-丁烯和3-溴-1-丁烯但很难生成4-溴-1-丁烯(CH_2-CH-CH=(?)Br HCH_2)。对丁二烯1,4-加成和1,2-加成的解释,目前的教材是根据正碳离子的分布情况和电荷的转移情况来解释的。物理学上认为:带电体系所带的电荷愈分散,体系愈稳定。化学上也引用了这一规律,从而推出正碳离子的安定性取决于正碳离子所带电荷的分散程度。这种解释不但难理解,也缺少“化学味”。电荷转移的观点也难使人信服。本文拟就从分子极化的观点,来解释共轭双烯的1,4-加成和1,2-加成。不对之处,请广
The nature of the conjugated double bond is relatively active. In the addition reaction, the main product is the 1,4-addition product, which also produces the 1,2-addition product. Such as butadiene and hydrogen bromide addition, the product is 1-bromo-2-butene and 3-bromo-1-butene but it is difficult to generate 4-bromo-1-butene (CH_2-CH-CH= (?) Br HCH_2). The explanation of the 1,4-addition and 1,2-addition of butadiene is explained by the current textbook based on the distribution of positive carbon ions and the transfer of charge. In physics, it is believed that the more charged the charged system is, the more stable the system is. Chemically, this rule is also quoted so that the stability of the positive carbon ion is determined by the degree of dispersion of the charge carried by the positive carbon ion. This explanation is not only difficult to understand, but also lacks the “chemical flavor.” The idea of charge transfer is also difficult to convince people. This article will explain the 1,4-addition and 1,2-addition of conjugated dienes from the viewpoint of molecular polarization. The wrong place, please