Alcohols, Phenols and Ethers

In Dow's process, sodium phenoxide is obtained by the reaction of chlorobenzene with NaOH at 573 - 623 K and 200 atm, which on acid hydrolysis forms phenol.

Formic acid (HCOOH) cannot be prepared from methyl magnesium bromide (CH,MgBr) while from all other reagents, it is obtained as 

(a) CH₃OH $\stackrel{\left[\mathrm{O}\right]}{\to }$ HCHO $\stackrel{\left[\mathrm{O}\right]}{\to }$ HCOOH

(b) CO + NaOH → HCOONa $\underset{∆}{\overset{{\mathrm{NaHSO}}_4}{\to }}$ HCOOH + Na₂SO₄

(c) Glycerol + Oxalic acid $\underset{{\mathrm{H}}_2\mathrm{O}}{\overset{383 \mathrm{K}}{\to }}$ HCOOH + glycerol

Mixture of anhydrous ZnCl₂, and cone. HCl is known as Lucas reagent. Lucas test is used for the distinction between primary, secondary and tertiary alcohols. The tertiary alcohol reacts immediately with Lucas reagent producing turbidity. The secondary alcohol gives turbidity within 5-10 min and primary alcohol do not give turbidity at all at room temperature. In the given alternates, 2-hydroxy-2-methyl propane is 3° alcohol, so it is more reactive.

General formula for both ethers and alcohols is C_nH_2n+2 but the functional group in ethers is -O- and in alcohols is -OH. Therefore, they are functional isomers.

Alcohols with same molecular weight are expected to have almost same boiling point however two more factors other than molecular weight are important, they are namely H-bonding and surface area of molecule. Both these factors are least in 3° alcohols and maximum in 1° alcohols. Hence, 3° alcohols have least boiling point while 1° alcohols have maximum boiling point.

Kolbe – Schmidt reaction is

The structures of possible alcohols having formula C₄H₉OH are as

Among these, 2-methyl propan-2-ol cannot be prepared by the reduction of carbonyl compounds.

In the above given reaction, the product is diethyl ether.

If temperature is high (i.e. 463 K), ethene is obtained.