Question

Show the complete reaction.
Methyl alcohol to pentan-3-ol.

Answer 1

Hint: An alcohol is denoted by an OH group. Methyl alcohol is a hydrocarbon that consists of an OH group. There is only one carbon in methyl alcohol. The molecular formula of methyl alcohol is $ C{H_3}OH $ .

Complete step by step solution:
The conversion of methyl alcohol to pentan-3-ol takes place in six steps which are as follows,
- $ C{H_3}OH\xrightarrow{{HBr}}C{H_{_3}}Br + {H_2}O $
When alcohols are treated with hydrogen bromide, they undergo a nucleophilic substitution reaction to generate an alkyl halide and water.
Methyl alcohol or methanol will proceed with an $ S{N^2} $ mechanism since they have a highly unfavourable mechanism.
- $ C{H_3} - Br + 2Na + Br - C{H_3} \to C{H_3} - C{H_3} + 2NaBr $
When methyl bromide is treated with sodium in the presence of dry ether as a catalyst, ethane is formed. This reaction is also known as wurtz reaction.
- $ C{H_3} - C{H_3}\xrightarrow{{B{r_2},h\nu }}C{H_3} - C{H_2} - Br + H - Br $
Ethane is reacted with bromine gas in the presence of sunlight and uv rays to give ethyl bromide.
- $ C{H_3}C{H_2} - Br + Mg\xrightarrow{{{\text{Dry ether, Mg}}}}C{H_3}C{H_2} - MgBr $
When ethyl bromide is reacted with magnesium in the presence of dry ether as catalyst, it forms ethyl magnesium bromide. Here ethyl magnesium bromide is also known as a Grignard reagent.
- $ C{H_3}C{H_2}MgBr + C{H_3}C{H_2}CHO \to C{H_3} - C{H_2} - C(OMgBr) - C{H_2} - C{H_3} $
When Grignard reagent or magnesium bromide is reacted with propanal it gives the product that is mentioned in the reaction.
- $ C{H_3}C{H_2}C(OMgBr)C{H_2}C{H_3}\xrightarrow{{{H_3}{O^ + }}}C{H_3} - C{H_2} - CH(OH) - C{H_2} - C{H_3} $
The hydronium ion when reacted gives hydrogen ion and the hydrogen ion bonds with oxygen to form pentan-3-ol.

Note:
-Methyl alcohol is used as a fuel for industries and factories. Methyl alcohol is also used in the formation of many products like ethane using wurtz reaction. It is used in the making of pentan-3-ol. It is used to make ethyl bromide or ethyl chloride.
-Pentan-3-ol is used in olfactory communication between organisms of the same species which elicit change in sexual or social behaviour. It is a substance used as an indicator of biological state.