Question

Convert propene to 1- nitropropane.

Answer 1

Hint: The reaction is the nitration of propene to 1- nitropropane. But it is not a direct addition but a substitution reaction in which the bromide group gets substituted by the nitro group. First, the alkene will be converted into alkyl halide by addition reaction and then this alkyl halide will get converted into nitro product which is the desired product.

Complete step by step answer :
The propene molecule is a three carbon chain with one double bond at first carbon. The conversion of propene to 1- nitropropane is not a direct addition reaction in which the nitro group and a hydrogen atom get attached across the double bond to the chain. This is in actual a substitution reaction where an halide is substituted by a nitro group. The propene gets converted to propyl bromide in the first step where the propene reacts with hydrogen bromide (HBr) in the presence of peroxide. It is a free radical reaction giving additional product prop-1-bromide. The reaction is written as -
$C{H_3} - CH = C{H_2} + HBr\xrightarrow{{Peroxide}}C{H_3} - C{H_2} - C{H_2}Br$
The second step is that the propyl bromide undergoes a nitration reaction to give product.
The propyl bromide reacts with silver nitrate to form 1- Nitro propane and silver bromide. The reaction is written as -
$C{H_2} - C{H_2} - C{H_2}Br\xrightarrow{{AgN{O_3}}}C{H_3} - C{H_2} - C{H_2}N{O_2} + AgBr$

Note: The peroxide in the first step of reaction is used to initiate the reaction. It forms free radicals of bromide ions and hydrogen free radicals that attack the alkene and initiate the reaction. This step is the initiation step. Then, there is a propagation of chain and after that termination.