Question

Convert $1 - $ Chlorobutane into the following compounds
1. Butane - $1$- ol
2. $1 - $Iodobutane
3. ${H_3}C - C{H_2} - C{H_2} - C{H_2} - CN$

Answer 1

Hint: Look for changes in functional groups and determine the reagent to use accordingly. The reagents should not produce this product as the major one.

Complete step by step answer:
1. The first reaction occurs with the change of the chloride functional group to the hydroxyl group. The number of chromosomes remains the same as well as the position of the functional group. For this process, the aqueous $KOH$ is chosen so that the substitution of the $O{H^ - }$ functional group can occur at the first carbon position removing the $C{l^ - }$.
${H_3}C - C{H_2} - C{H_2} - C{H_2} - Cl\xrightarrow{{Aq.KOH}}{H_3}C - C{H_2} - C{H_2} - C{H_2} - OH$
2. In the second reaction, one halogen is substituted with another halogen and hence both the reactants and product. Hence both the reactants and products are alkyl halides and the $C{l^ - }$ is substituted by ${I^ - }$. Hence $1$ -Chlorobutane is converted to $1$ -Iodobutane due to the effects of $NaI$ in the presence of Acetone. The acetone in the reaction mixture helps in the process of substitution.
${H_3}C - C{H_2} - C{H_2} - C{H_2} - Cl\xrightarrow{{NaI + Acetone}}{H_3}C - C{H_2} - C{H_2} - C{H_2} - I$
3. In the third reaction, chloride is substituted by the cyanide residue in the same specific position. Here for the conversion potassium cyanide is used as it can form alkyl cyanide easily. The release of chlorine takes place from $1$ -Chlorobutane and then cyanide causes a nucleophilic attack on the same carbon residue resulting in the formation of ${H_3}C - C{H_2} - C{H_2} - C{H_2} - CN$.
${H_3}C - C{H_2} - C{H_2} - C{H_2} - Cl\xrightarrow{{KCN}}{H_3}C - C{H_2} - C{H_2} - C{H_2} - CN$
In all these organic reactions the substitutions of the specific molecule take place at the same carbon position in the molecule. The reactants are used according to the requirement so that all the nucleophilic attack takes place in the right region. This is to ensure that even though the carbocations are more stable at the secondary positions or two-degree carbons, the changes take place in the one-degree carbon position only.

Note: In all the reactions the carbon number is not changed which means there is no process of step-up or step-down, but if that is required the reaction proceeds in a different manner where at first carbon number is increased and then the associated changes. Here the functional groups are changed and hence very specific reactants are used.