.1 Select the longest carbon chain including double bonds as the main chain. It is called "a certain alkene" according to the number of carbon atoms contained in the main chain. Alkenes with more than ten carbon atoms are named with lowercase Chinese numbers plus "carbon alkene". .

2. When numbering, number the carbon atoms in the main chain sequentially starting from the end close to the double bond. The position of the double bond is represented by the smaller of the two double bond carbon atoms. When numbering, first consider that the number of the double bond position is as small as possible, and secondly, take into account that other substituents have lower positions.

3. Write the position of the double bond before the name of the parent, separated by a half-word line "-", and then write the position, number and name of the substituents before the position of the double bond.

The remaining group after removing a hydrogen atom from an alkene molecule is called an alkenyl group. When naming an alkenyl group, the numbering begins with the carbon atom on which the free radical is located.

order rules

In the presence of a catalyst, olefins react with hydrogen to form the corresponding saturated hydrocarbons

The relative rates of catalytic hydrogenation of different olefins are: ethylene > monoalkyl substituted ethylene > dialkyl substituted ethylene > trialkyl substituted ethylene > tetraalkyl substituted ethylene

Alkenes contain carbon-carbon double bonds and can undergo electrophilic addition reactions with reagents such as halide, hydrogen halide, water, and sulfuric acid.

1 Adding halogen, alkenes and halogens can react at room temperature to generate the corresponding ortho-dihalogenated hydrocarbons.

2 Add hydrogen halide, and the electrophilic addition reaction between the alkene and the hydrogen halide will produce an alkyl halide.

The order of activity of the reaction between hydrogen halides and alkenes is consistent with the order of their acidity: HI > HBr > HCl.

Markov's rule: When an addition reaction occurs between asymmetric alkenes and asymmetric reagents such as hydrogen halide, the hydrogen atom in the hydrogen halide is added to the double-bonded carbon atom containing more hydrogen, and the halogen atom or other atom and group is added to On the double bonded carbon atom that contains less hydrogen.

Regional selectivity means that when the orientation of the reaction is likely to generate several products, only one product is generated or mainly one product is generated. Applying Markov's rule can correctly predict the main products of the addition reaction of asymmetric alkenes and asymmetric reagents

It refers to the introduction of an atom or group into an organic molecule, which changes the density distribution of the bonding electron cloud in the molecule. This change can not only occur on the directly connected atoms, but can also affect adjacent atoms in the molecule. This change The effect of transferring bond electrons in a certain direction along the atomic chain due to the polarity of an atom or group is called the induction effect

The induction effect can be transmitted from near to far along the molecular chain, but it weakens rapidly as the carbon chain grows. Generally, after three carbon atoms, the influence of the induction effect can be ignored.

Tertiary carbon>Secondary carbon>Primary carbon>Methyl carbon

Alkenes can undergo addition reactions with sulfuric acid at around 0°. The reaction also proceeds through the carbocation mechanism and follows Markovian addition.

Alkenes can also be hydrated into alcohols under acid catalysis.

In the presence of light or peroxide, HBr adds to asymmetric alkenes, mainly obtaining anti-Martens addition products.