Formaldehyde | Preparation, Properties, & Uses |

Formaldehyde.

Formaldehyde is the simplest fellow member of the aldehyde family.
Preparation. It is manufactured

By dehydrogenation of ethanol. Methanol vapours are passed over heated argent catalyst at 300°C.

By air oxidation of methanol. Methanol vapours in addition to express total of air are passed over heated argent catalyst at 450°C.

By air oxidation of marsh gas inwards the presence of diverse metallic element oxides.

Since formaldehyde is a gas, the production is marketed every bit 40% aqueous solution nether the advert Formalin.

Physical Properties.

Formaldehyde is a colourless gas, bp -21°C. It has an irritating odour. It is extremely soluble inwards water.

Chemical Properties.

Formaldehyde is unlike from other aldehydes. It contains no alkyl grouping inwards the molecules. Both hydrogen atoms may live regarded every bit beingness job of an aldehyde group. As a result, several reactions of formaldehyde arc unlike from those of other aldehydes.

Reaction amongst Ammonia. 

When treated amongst ammonia, it does non give an aldehyde ammonia, only forms hexamethylene tetramine.

hexamethylene tetramine is used a urinary antiseptic, in addition to has been given the merchandise advert of  Urotropine.

Reaction amongst Sodium Hydroxide (Cannizzaro Reaction).

Formaldehyde reacts amongst concentrated NaOH solution to shape methanol in addition to sodium formate.

Reaction amongst Alcohols.

Like other aldehydes, it reacts amongst alcohols to shape acetals. For example, formaldehyde reacts amongst methanol inwards the presence of HCl to shape Methylal.

Uses.

Formaldehyde is sold every bit 40% aqueous solution nether the advert FORMALIN in addition to is used inwards this shape for unopen to purposes. Formalin is used.

1. As a full general antiseptic.
2. In the industry of urinary antiseptic Urotropine.
3. In the introduce creation of biological specimens.
4. In the industry of synthetic dyes similar Pararosaniline in addition to Indigo.
5. In the industry of synthetic plastics such every bit Bakelite in addition to Melmac.