Ethanol and methanol identification Abdullah turkey

ALCOHOLS An alcohol is an organic compound with a hydroxyl (OH) functional group on an aliphatic carbon atom. Because OH is the functional group of all alcohols, we often represent alcohols by the general formula

Classification according to carbon attached to hydroxyl group

Physical characters: of Methanol Condition: Liquid, mobile. Color : colorless. Odor : alcoholic odor. Miscibility: Miscible with H2O, L.P → neutral.

Chemical Reactions: Action of Soda lime: Not done. Action of FeCl3: No action Action of NaOH : No action Action of conc H 2 SO 4 : No action Action of Na 2 CO 3 : No action

Special test: 1- Esterification: (Salicylic acid): …vick’s odour (smell of wintergreen oil ) 1- In dry test tube put 1 ml of methyl alcohol then add o.5 ml of conc. H2SO4 and o.5 gm. of salicylic acid or its derivatives. 2- Heat the mixture for 3mints in water bath, then cool and pour the contents in a beaker containing about 30 ml of sodium carbonate solution. 3- Note the characteristic odor of methyl salicylate.

partial oxidation: 1- In dry test tube, place 0.5 ml of K 2 Cr 2 O 7 and 0.5 ml of conc. H2SO4, then cool. 2- Add 0.5 ml of methanol and boil gently (on water bath) notice the pungent odor of formaldehyde and change of color to green.

Methanol is an important industrial material and it is used 1.in the manufacture of formaldehyde. 2. As a solvent in the paint and varnish industry. as an anti-Freeze in car radiators..3

Ethanol Physical characters: Condition: Liquid, mobile. Color : colorless. Odor : alcoholic odor. Miscibility: Miscible with H2O, L.P → neutral.

Chemical Reactions: Action of Soda lime: Not done. Action of FeCl3: No action Action of NaOH : No action Action of conc H 2 SO 4 : No action Action of Na 2 CO 3 : No action

Special test: 1- Esterification: Place 1 ml of ethanol in dry test tube, then add 0.5 ml of conc. H 2 SO 4 and 1 ml of acetic acid. 2- Heat the mixture gently for 3 mints in water bath, cool and pour the tube into beaker containing sodium carbonate solution.

3- Not the characteristic odor of ester.

Iodoform test: 1- Add 3 ml of iodine solution to 1 ml of ethyl alcohol then add NaOH solution drop wise until the color of solution becomes straw yellow. 2- Gentle warm the solution for 5 mints 3- yellow ppt. of iodoform is appearing

This test is specific for alcohols which have a free methyl group (- CH3 )and a hydrogen attached to the carbon bearing the hydroxyl group such as ethanol and sec-butanol.

1- Oxidation reaction 1- Place 1 ml of K 2 Cr 2 O 7 and 0.5 ml of conc. H 2 SO 4, then cool. 2- Add 0.5 ml of ethanol and boil gently (on water bath) 3- Notes the odor of acetaldehyde and change the color solution to green.