+ (CH ) S + CO + CO + 2HCl propanone Et N XII U11-Hydroxy XII U11-Hydroxy - - - - Biological oxidation The fermentation of the food consumed by an animal produces alcohol. To detoxify the alcohol, the liver produces an enzyme called alcohol dehydrogenase (ADH). Nicotinamide adenine dinucleotide (NAD) present in the animals act as an oxidising agent and ADH catalyses the oxidation of toxic alcohols into non-toxic aldehyde. CH CH OH NAD + ADH CH CHO + NADH + H + ethanol ethanal Catalytic dehydrogenation When the vapours of a primary or a secondary alcohol are passed over heated copper at 573K, dehydrogenation takes place to form aldehyde or ketone.
Cu K CHO + H ethanol ethanal CH Cu K Propan - - ol propanone + H Tertiary alcohols undergo dehydration reaction to give alkenes. Cu K C = CH - methylpropan - - ol - methylprop - - ene H C H C + H O Esterification Alcohols react with carboxylic acids in the presence of an acid to give esters Example HO H + ethanol ethanoicacid ethylethanoate XII U11-Hydroxy XII U11-Hydroxy - - - - Reactions of Glycol Ethylene glycol contains two primary alcoholic groups and it exhibits the usual reactions of hydroxyl group. Like other primary alcohols, it reacts with metallic sodium to form monosodium glycolate and disodium glycolate. The hydroxyl groups can be converted to the halide groups by treating glycol with halic acid (or with PCl / PCl / SOCl .
) When ethylene glycol is treated with HI or P/I2, , – diiodoethane is first formed which decomposes to give ethene. PI I I ethane - , - diol , - diiodoethane ethene -I On heating with conc HNO3 in the presence of Con. H SO , ethylene glycol forms dinitroglycol. ethane - , - diol HNO Conc H SO NO NO