It can be done by the following reaction.
The direct hydration of alkene leads to the formation of alcohols. The reaction takes place according to the markovnikov’s rules for addition reaction. For example we can make 2-methyl propan-2-ol (tertiary – butyl alcohol) from 2- methyl propene (Isobutylene) as shown in the above reaction.
The ethylene chlorohydrin can be prepared by the reaction of ethylene with Hypochlorus acid (Hypohalus acid) It is a kind of addition reaction.
It is a type of addition reaction in which the hydroxyl and halogen groups are introduced in alkene molecule . The alkenes react with freshly prepared solution of hypohalus acid. The acid is formed by the reaction of dihalogen with water. The hypohalus acid gives Halohydrin on reacting with alkene.
The mechanism for this kind of reaction involves the formation of free radicals, and the relative stability of different molecules will decide the formation of major and minor products. Step 1 , Chain initiation :- First of all , the homolytic cleavage takes place in peroxide molecule as shown below :- Step2 Chain propagation :-
It is the phenomenon which is seen in case of addition of hydrogen halide in the presence of a peroxide like benzoyl peroxide. The major product in this kind of reaction is the alkane in which the halide is attached to terminal or the less substituted carbon atom as shown below.
This is due to the following reason :- This is in accordance with sytzeff rule that whenever two alkenes are theoretically possible during a dehydrohalogenation reaction , it is always the more highly substituted alkene which predominates . It can also be best understood by the following illustrations showing the stabilizes of primary(1°) , secondary
The haloalkanes give alkenes on undergoing beta elimination. But in case if we there is unsymmetrical haloalkane , the product formation follows Sytzeff rule as shown below.
In case of unsymmetrical alkenes the addition of hydrogen halide takes place according to the markovnikov’s rule . During this reaction under markovnikov’s rule the positive part of the attacking reagent joins with the carbon with more number of Hydrogen and the negative part of attacking reagent joins with the more substituted carbon.
We can make haloalkanes from the alkenes by treating them with rhe hydrogen halides HX . Here the double bond is converted into single bond , hydrogen and halogen gets attached to the carbons involved in double bond.
We can make the dibromoethane from ethene by the addition of halogen in ethene , in the presence of carbon tetrachloride. In the presence of ether as a solvent the above reaction takes place. The dihalo products are formed in which the halogen groups are present on adjacent carbon atoms.
By catalytic hydrogenation we can get the alkanes from the alkenes. The reaction takes place by reacting ethene with hydrogen in the presence of platinum and pladium and Rany nickel (active form of Nickel) Here is the reaction :-
The mechanism involves the following steps :- Step 1 :- In first step the polarity is developed on the bromine molecule , and the partial positive side of the bromine molecule attacks on the carbon atom of the double bond. This leads to the formation of carbocation. Step 2 :- In second step the negative
Alkenes give electrophillic addition reactions because of the following reasons:- 1. The pie electrons of the double bond attract electrophiles . 2. The electron density is more on the C-C double bond , so the electrophiles preferably attack on it as compared to the electrophiles which are repelled.
In this reaction the decarboxylation of dicarboxylic acids take place . The potassium salts of dicarboxylic acid give alkene as the COO- group is removed as CO2 , this leads to the formation of double bond between two adjacent carbon atoms.
The complete mechanism takes place in three steps as shown below :- Step 1 :- Step 1 involves the release of Hydronium ion (proton) and then the attack of proton on the lone pair electrons of oxygen. By this way protonated alcohol is formed. Step 2 :- This step is slow and rate determining step.
By just heating in the presence of methanol we can get the alkene by treating the vicinal dihalides with zinc. Here Is the complete reaction:-
In these kind of reactions the Saytzeff rule is followed. Here is the reaction and its conditions:-
We can obtain the alkenes from alkyl halides by the Dehydrohalogenation. In this kind of reaction the halogen and hydrogen from adjacent carbon are removed to make a double bond in the presence of alcohlic KOH . The reaction is shown below.
It is a kind of reaction in which under suitable conditions of temprature and pressure a simple alkane can give various products. As shown below. Pyro means the heat and lysis means the breaking, so it is a process of breaking the alkanes in the presence of heat.
In this kind of reduction the alkynes are reduced with sodium in liquid ammonia. This leads to the formation of Trans alkenes.