Terms Related to Alcohols
( a ) Rectified spirit It contains 95 % ethyl alcohol and 45 % water . It is an azeotrope ( constant boiling mixture ) and boils at 74 °
( b ) Absolute alcohol Alcohol containing no water , i . e ; 100 % C2H5OH is known as absolute alcohol . It is prepared as follows . ( i ) Quick lime process ( ii ) Azeotropic method
( c ) Methylated spirit The rectified spirit rendered poisonous by addition of 4-5 % methyl alcohol , traces of pyridine and some copper sulphate and is known as methylated spirit or denatured alcohol .
( d ) Power alcohol Alcohol mixed with petrol or fuel and used In internal combustion engines Is known as power alcohol .
( e ) Wood spirit Methyl alcohol ( CH3OH ) is also called wood spirit . It is obtained by destructive distillation of wood . Pyroligneous add , the product of destructive distillation of wood , contains acetic acid ( 10 %), methyl alcohol ( 25 %) and acetone ( 05 %). Drinking of methanol causes blindness .
( f ) Grain alcohol Ethyl alcohol C2H5OH is also called grain alcohol . It is used In the preparation of various beverages containing different percentages .
Dihydric Alcohols
These are generally called glycols because of their sweet taste . Ethylene glycol ( CH2OH – CH2OH ) is the first and most important member of dihydric alcohol series .
Methods of Preparation