Question

Give structures of the products you would expect when each of the following alcohol reacts with (a) $HCl - ZnC{l_2}$ (b) $HBr$ and (c)$SOC{l_2}$
i.Butan-1-ol
ii.2-Methylbutan-2-ol

Answer 1

Hint: The reaction of the different reagents is different with the different substituents or the reactants under the similar reaction conditions which in turn depends upon the reactivity of the substituents and the catalysts used in the reaction conditions.

Complete step by step answer:
a)When Butan-1-ol and 2-Methylbutan-2-ol reacts with $HCl - ZnC{l_2}$ which is also known as the Luca’s reagent they react differently no reaction take place in case of butan-1-ol while 2- chloro-2-methyl butane is formed when 2- methylbutan-2-ol reacts with the same reagent. The reactions are given below:
i.$C{H_3} - C{H_2} - C{H_2} - C{H_2} - OH\xrightarrow{{HCl/ZnC{l_2}}}$ No reaction
 With the Luca’s reagent $HCl - ZnC{l_2}$ primary amines do not react appreciably at room temperature.
ii.$C{H_3} - C{H_2} - C{H_3} - C - OH - C{H_3}\xrightarrow{{HCl/ZnC{l_2}}}C{H_3} - C{H_2} - C{H_3} - C - Cl - C{H_3} + {H_2}O$
The tertiary alcohols react immediately with the Lucas reagent
b)When Butan-1-ol and 2-Methylbutan-2-ol reacts with $HBr$, in case of butan-1-ol
 1- Bromobutane is formed while 2- bromo-2-methyl butane is formed when 2- methylbutan-2-ol reacts with the same reagent. The reactions are given below:
i.\[C{H_3} - C{H_2} - C{H_2} - C{H_2} - OH + HBr\xrightarrow{{ - {H_2}O}}C{H_3} - C{H_2} - C{H_2} - C{H_2} - Br\]
ii.$C{H_3} - C{H_2} - C{H_3} - C - OH - C{H_3} + HBr \to C{H_3} - C{H_2} - C{H_3} - C - Br - C{H_3} + {H_2}O$
c)When Butan-1-ol and 2-Methylbutan-2-ol reacts with, in case of butan-1-ol
 1- chloro-butane is formed while 2- chloro-2-methyl butane is formed when 2- methylbutan-2-ol reacts with the same reagent. The reactions are given below:
i.\[C{H_3} - C{H_2} - C{H_2} - C{H_2} - OH + SOC{l_2} \to C{H_3} - C{H_2} - C{H_2} - C{H_2} - Cl + S{O_2} + HCl\]
ii.$C{H_3} - C{H_2} - C{H_3} - C - OH - C{H_3} + SOC{l_2} \to C{H_3} - C{H_2} - C{H_3} - C - Cl - C{H_3} + S{O_2} + HCl$
As is evident from the above that even the same reagent reacts differently with the different reactants under the same reaction conditions as well.

Note:
 In an organic chemical reaction some bonds are broken and some bonds are formed during the chemical reaction, where the reactants react and the products are formed during the reaction which largely depends upon the reaction conditions as well.