There is a group of compounds in which carbon forms only two bonds. These neutral divalent carbon compounds are called carbenes. Most carbenes are highly unstable compounds that are capable of only fleeting existence. Soon after carbenes are formed they usually react with another molecule

One complication associated with alkene hydration is the occurrence of arrangements

In the addition of HX to an unsymmetrically substituted alkene, the hydrogen atom adds to the carbon atom of the double bond that already has the greater number of hydrogen atoms and that the X group adds to the carbon having more alkyl substituents. Markovnikov’s rule can be restated by saying that, in the addition of HX to an alkene, the more stable carbocation intermediate is formed

Acetylenic hydrogens can be deprotonated with relatively strong bases (sodium amide is typical)

1. The experimental conditions — temperature and acid concentration — that are required to being about dehydration are closely related to the structure of the individual alcohol. The relative ease with which alcohols undergo dehydration is in the following order:

Alkenes are hydrocarbons whose molecules contain the carbon-carbon double bond. Alkynes are hydrocarbons whose molecules contain the carbon-carbon triple bond

SN2 reactions are highly useful in organic synthesis because they enable use to convert one functional group into another —— functional group transformation (functional group interconversion)

First order overall (一级反应) The reaction is a unimolecular nucleophilic substitution（单分子亲核取代反应）

The C—X bond of alkyl halides is polarized. The carbon atom bears a partial positive charge, The halogen atom a partial negative charge

一、基本概念 二、氧化还原反应方程配平 三、电极电势 四、电势图及应用 五、电解 六、化学电源