Formic Acid : Preparation, Properties, Uses

Formic Acid.

Formic acid derives its cite from the fact that it was kickoff obtained past times distillation of ants (Latin, Formica =ant):

Preparation. Formic acid may hold upward obtained every bit follows:

(1) From Methanol. By the oxidation of methanol amongst acidified sodium dichromate solution.

(2) From Oxalic Acid. Formic acid is prepared inwards the laboratory past times heating oxalic acid amongst glycerol catalyst at 110°C.

Laboratory Method.

Anhydrous glycerol (50 ml) as well as powdered oxalic acid (40 g) are placed inwards a flask as well as the apparatus laid upward every bit shown inwards Fig. 1.1 The flask is heated at 1 C till the development of carbon dioxide (marked past times effervescence) ceases. The reaction flask is so cooled as well as a fresh lot of oxalic acid (40 g) is added. The mixture is in ane trial again heated at 110°C when an aqueous solution of formic acid collects inwards the receiver.

The aqueous formic acid is neutralised amongst Pb carbonate. The solution of Pb formate therefore produced is filtered as well as concentrated. The crystals of Pb formate are so charged inwards the inner underground of a water-condenser as well as the apparatus laid upward every bit shown inwards Fig. 1.2. Hydrogen sulphide is allowed to transcend through the condenser spell steam is passed through its outer jacket. The anhydrous formic acid collecting inwards the receiver flask is freed from dissolved hydrogen sulphide past times distilling over fresh Pb formate.

Anhydrous formic acid may likewise hold upward made inwards the laboratory past times distilling a mixture of sodium formate as well as sodium hydrogen sulphate.

(3) From Carbon Monoxide. Formic acid is prepared industrially past times beating carbon monoxide.

with sodium hydroxide at 150°C as well as nether the pressure level of 8 atmospheres.

The complimentary acid is liberated from its sodium tabular array salt past times reaction amongst sulphuric acid.

Physical properties.

Formic acid is a colourless, abrupt smelling, irritating liquid, bp 100.8°C. It is miscible amongst water, ethanol, as well as there. It is really corrosive as well as causes bumps as well as blisters on the skin.

Chemical Properties.

Formic acid is unique because it contains both an aldehyde grouping as well as a carboxyl group.

Uses. 

Formic acid is used :

1. In stuff dyeing as well as finishing.
2. As a coagulating agent for security latex.
3. In leather tanning.
4. In the preservation of fruits.
5. As an antiseptic.
6. In the handling of gout.
7. In the laboratory training of carbon monoxide.