it may be fortified by the addition of ammonium sulphate or ammonium phosphate . (iii) Addition of Yeast The solution obtained in step (ii) is collected in large ‘fermentation tanks’ and yeast is added to it. The mixture is kept at about 303K for a few days. During this period, the enzymes invertase and zymase present in yeast, bring about the conversion of sucrose into ethanol.
C H O + H O C H O + C H O Sugar invertase fructose glucose C H O 2C H OH + CO glucose or fructose zymase ethanol The fermented liquid is technically called wash . (iv) Distillation of 'Wash' The fermented liquid (i.e. wash), containing to percent alcohol, is now subjected to fractional distillation. The main fraction drawn is an aqueous solution of ethanol which contains Table .
IUPAC Name of various classes of compounds No. of carbons atoms IUPAC Name Alcohols Aldehydes Ketones Carboxylic acid Methanol (CH OH) Methanal (HCHO) Methanoic acid (HCOOH) Ethanol (CH CH OH) Ethanal (CH CHO) Ethanoic acid (CH COOH) Propanol (CH CH CH OH) Propanal (CH CH CHO) Propanone (CH COCH ) Propanoic acid (CH CH COOH) Butanol (CH CH CH CH OH) Butanal (CH CH CH CHO) Butanone (CH COCH CH ) Butanoic acid (CH CH CH COOH) Pentanol (CH CH CH CH CH OH) Pentanal (CH CH CH CH CHO) Pentanone (CH COCH CH CH ) Pentanoic acid (CH CH CH CH COOH) . % of ethanol and . % of water.
This is called rectified spirit . This mixture is then refluxed over quicklime for about to hours and then allowed to stand for hours. On distillation