Methyl alcohol is the first most and smallest alcohol in organic compounds. Methanol is produced naturally in the anaerobic metabolism by varieties of bacteria, and is ubiquitous in the environment. As a result, there is a small fraction of methanol vapor in the atmosphere. Over the course of several days, atmospheric methanol is oxidized with the help of sunlight to carbon dioxide and water.
Preparation methods of Methanol:
By the hydrolysis of methyl halides:
It is the laboratory method of preparation where methyl halide boiled with aqueous sodium hydroxide or aqueous potassium
hydroxide. This base hydrolysis produces methyl alcohol.
Industrial method of preparation:
Water gas is a mixture of CO and H2 is mixed with hydrogen and passed over heated catalyst
[Cr2O3 or ZnO] at 350°C. Carbon monoxide present in water gas is reduced to give methanol.
Methanol is a biodegradable stable chemical that is produced and transported around the globe everyday for
many industrial and commercial applications.
Physical properties:
Methanol is a colorless liquid having a strong alcoholic odor. It is an inflammable, highly toxic liquid in nature. Small doses
of it on consumption can cause blindness, whereas large doses prove fatal.
It is soluble in water and most of the organic solvents in all proportions. It boils at 64.5°C.
Chemical properties:
Reaction with sodium:
Methanol has acidic proton when treated with sodium forms sodium methoxide and liberates hydrogen gas.
With conc. sulfuric acid:
When methyl alcohol reacted with conc. sulfuric acid at 140°C dehydration of alchol takes place forms dimethyl ether.
Oxidation by acidified K2Cr2O7:
Methyl alcohol treated with powerful oxidizing agent like acidified potassium dichromate, it is oxidized to formic acid.
With acetic acid:
It reacts with acetic acid in the presence of sulfuric acid to form methyl acetate. This reaction is also called as
esterification of alcohols.
A solution of 50% Methylated Spirits and 50% Water can be used for window cleaning.
Uses of methyl alcohol:
- Methanol is used as a basic component for several chemicals and consumer products such as Plastic, Synthetic fibers, Colors, Resins, Laminate for glass insulation, Glues, Solvents, Caret fabric, Insulation, Laundry detergent,Pigments and colors.
- Methanol or methyl alcohol is used as solvent for paints and varnishes.
- It is used in the manufacture of formaldehyde and formic acid.
- It is used in making ethyl alcohol unfit for drinking. 5% of methyl alcohol is added to ethyl alcohol to form methylated spirit which is unfit for human consumption and this is used as cleaning agent.
- Methanol can decrease the freezing point of water so it is mixed with the water in radiators of automobiles, it prevents freezing of water in cold climate.