Formamide, also known as methanamide, is an amide derived from formic acid.
It is a clear liquid which is miscible with water and has an ammonia-like odor.
It is chemical feedstock for the manufacture of sulfa drugs, other pharmaceuticals, herbicides,
pesticides and the manufacture of hydrocyanic acid.
It has been used as a softener for paper and fiber.
It is a solvent for many ionic compounds.
It has also been used as a solvent for resins and plasticizers.Formamides are compounds
of the type RR′NCHO.
One important formamide is dimethylformamide, (CH3)2NCHO.
== Production ==
=== Historical production ===
In the past, formamide was produced by treating formic acid with ammonia, which produces ammonium
formate, which in turn yields formamide upon heating:
HCOOH + NH3 → HCOO−NH+4 HCOO−NH+4 → HCONH2 + H2OFormamide is
also generated by aminolysis of ethyl formate: HCOOCH2CH3 + NH3 → HCONH2 + CH3CH2OH
=== Modern production === The current industrial process for the manufacture
of formamide involves either the carbonylation of ammonia:
CO + NH3 → HCONH2An alternative two-stage process involves the ammonolysis of methyl
formate, which is formed from carbon monoxide and methanol:
CO + CH3OH → HCOOCH3 HCO2CH3 + NH3 → HCONH2 + CH3OH
== Applications == Formamide is used in the industrial production
of hydrogen cyanide.
It is also used as a solvent for processing various polymers such as polyacrylonitrile.
=== Reactions === Formamide decomposes into carbon monoxide
and ammonia at 180 °C.
HCONH2 → CO + NH3Traces of hydrogen cyanide (HCN) and water are also observed.
In the presence of solid acid catalysts, formamide dehydrates to HCN:
HC(O)NH2 → HCN + H2O
=== Niche or laboratory applications === Formamide is a constituent of cryoprotectant
vitrification mixtures used for cryopreservation of tissues and organs.
Formamide is also used as an RNA stabiliser in gel electrophoresis by deionizing RNA.
In capillary electrophoresis, it is used for stabilizing (single) strands of denatured
DNA.
Another use is to add it in sol-gel solutions in order to avoid cracking during sintering.
Formamide, in its pure state, has been used as an alternative solvent for the electrostatic
self-assembly of polymer nanofilms.Formamide is used to prepare primary amines directly
from ketones via their N-formyl derivatives, using the Leuckart reaction.
== Biochemistry == Formamides are intermediates in the methanogenesis
cycle.
=== Prebiotic chemistry ===
Formamide has been proposed as an alternative solvent to water, perhaps with the ability
to support life with alternative biochemistries to that currently found on Earth.
It forms by the hydrolysis of hydrogen cyanide.
With a large dipole moment, its solvation properties are similar to those of water.Formamide
has been shown to convert to traces of guanine upon heating in the presence of ultraviolet
light.
== Safety == Formamide is moderately irritating to the
eyes, skin and mucous membranes.
Inhalation of large amounts of formamide vapor may require medical attention.
It is also a teratogen.
Formamide has been shown to exhibit hematoxicity in animals and is considered hazardous by
prolonged exposure through inhalation, oral intake and dermal absorption.
Formamide should never be handled without proper safety attire including gloves and
goggles