Formamide

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.[4]

Formamide
Ball and stick model of formamide
Space-filling model of the formamide molecule
Names
Preferred IUPAC name
Formamide[1]
Systematic IUPAC name
Methanamide
Other names
Carbamaldehyde
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.766
KEGG
UNII
Properties
CH3NO
Molar mass 45.04 g/mol
Appearance Colorless, oily liquid[2]
Density 1.133 g/cm3
Melting point 2 to 3 °C (36 to 37 °F; 275 to 276 K)
Boiling point 210 °C (410 °F; 483 K)
Miscible
Vapor pressure 0.08 mmHg at 20 °C
Acidity (pKa) 23.5 (in DMSO)[3]
−2.19×10−5 cm3/mol
Hazards
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
2
0
Flash point 154 °C (309 °F; 427 K) (closed cup)
NIOSH (US health exposure limits):
PEL (Permissible)
 none[2]
REL (Recommended)
 TWA 10 ppm (15 mg/m3) [skin][2]
IDLH (Immediate danger)
 N.D.[2]
Related compounds
Related compounds
 Carbamic acid
Dimethylformamide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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:[5]

HCOOH + NH3 → HCOO−NH+
4
HCOO−NH+
4 → HCONH2 + H2O

Formamide is also generated by aminolysis of ethyl formate:[6]

HCOOCH2CH3 + NH3 → HCONH2 + CH3CH2OH

Modern production

The current industrial process for the manufacture of formamide involves either the carbonylation of ammonia:[4]

CO + NH3 → HCONH2

An 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.[7]

Reactions

Formamide decomposes into carbon monoxide and ammonia at 180 °C.

HCONH2 → CO + NH3

Traces of hydrogen cyanide (HCN) and water are also observed.

In the presence of solid acid catalysts, formamide dehydrates to HCN:[7]

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.[8]

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.

Cycle for methanogenesis, showing two formamide-containing intermediates.[9]

Prebiotic chemistry
Main article: Hypothetical types of biochemistry

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.[10]

Formamide has been shown to convert to traces of guanine upon heating in the presence of ultraviolet light.[11]

Safety

Formamide is moderately irritating to the eyes, skin and mucous membranes.[12] Inhalation of large amounts of formamide vapor may require medical attention.[13][14] It is also a teratogen.[15] Formamide has been shown to exhibit hematoxicity in animals and is considered hazardous by prolonged exposure through inhalation, oral intake and dermal absorption.[16] Formamide should never be handled without proper safety attire including gloves and goggles.

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References
  1. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 841. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The traditional name ‘formamide’ is retained for HCO-NH2 and is the preferred IUPAC name.
  2. NIOSH Pocket Guide to Chemical Hazards. "#0295". National Institute for Occupational Safety and Health (NIOSH).
  3. F. G. Bordwell; J. E. Bartmess; J. A. Hautala (1978). "Alkyl effects on equilibrium acidities of carbon acids in protic and dipolar aprotic media and the gas phase". J. Org. Chem. 43 (16): 3095–3101. doi:10.1021/jo00410a001.
  4. Hohn, A. (1999). "Formamide". In Kroschwitz, Jacqueline I. (ed.). Kirk-Othmer Concise Encylclopedia of Chemical Technology (4th ed.). New York: John Wiley & Sons, Inc. pp. 943–944. ISBN 978-0471419617.
  5. Lorin, M. (1864). "Preparation of Formamide by means of Formiates and Oxalates". The Chemical News and Journal of Physical Science. IX: 291. Retrieved 14 June 2014.
  6. Phelps, I. K.; Deming, C. D. (1908). "The Preparation of Formamide from Ethyl Formate and Ammonium Hydroxide". The Chemical News and Journal of Physical Science. 97: 86–87. Retrieved 14 June 2014.
  7. Bipp, H.; Kieczka, H. (2012). "Formamides". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a12_001.pub2.CS1 maint: multiple names: authors list (link)
  8. Vimal K. Kamineni; Yuri M. Lvov; Tabbetha A. Dobbins (2007). "Layer-by-Layer Nanoassembly of Polyelectrolytes Using Formamide as the Working Medium". Langmuir. 23 (14): 7423–7427. doi:10.1021/la700465n. PMID 17536845.
  9. Thauer, R. K. (1998). "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson". Microbiology. 144: 2377–2406. doi:10.1099/00221287-144-9-2377. PMID 9782487.
  10. Committee On The Limits Of Organic Life In Planetary Systems (2007). The Limits of Organic Life in Planetary Systems. Washington, DC: The National Academies Press. p. 74. ISBN 0-309-66906-5. Retrieved 2012-08-29.
  11. "Origin of Life: Adding UV Light Helps Form 'Missing G' of RNA Building Blocks". Science Daily. June 14, 2010.
  12. TOXNet Formamide HSDB: Formamide
  13. Warheit DB, Kinney LA, Carakostas MC, Ross PE (1989). "Inhalation toxicity study of formamide in rats". Fundamental and Applied Toxicology. 13 (4): 702–713. doi:10.1093/toxsci/13.4.702. PMID 2620791.
  14. MSDS for formamide, hazard.com
  15. Lab use of formamide, University of Bath
  16. Archived 2015-07-10 at the Wayback Machine ECHA Formamide
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