Dimethylformamide is an organic compound with the formula2NC(O)H. Commonly abbreviated as
DMF, this colourless liquid is miscible with water and the majority of organic liquids.
DMF is a common solvent for chemical reactions. Dimethylformamide is odorless whereas technical
grade or degraded samples often have a fishy smell due to impurity of dimethylamine. As
its name indicates, it is a derivative of formamide, the amide of formic acid.
Dimethylformamide is a polar aprotic solvent with a high boiling point. It facilitates
reactions that follow polar mechanisms, such as SN2 reactions. Dimethylformamide can be
synthesized from methyl formate and dimethylamine or by reaction of dimethylamine with carbon
monoxide. Dimethylformamide is reactive toward strong bases such as sodium hydroxide or strong
acids such as hydrochloric acid or sulfuric acid and is hydrolyzed back into formic acid
and dimethylamine, especially at elevated temperatures.
Structure and properties Due to the contribution of the two major resonance
structures of an amide, the bond order of the carbonyl C=O bond is reduced and that
of the carbon–nitrogen bond is increased. Thus the infrared spectrum of DMF shows a
lower C=O stretching frequency at 1675 cm−1 than an unsubstituted C=O bond. Also, because
of the partial double bond character, the rotation about the C-N axis is slow at room
temperature, making the two methyl groups inequivalent on the NMR time scale, giving
rise to two singlets of 3 protons each at δ 2.97 and 2.88, instead of one singlet of
6 protons in the proton NMR spectrum. DMF is miscible with water in all proportions.
The vapour pressure at 20°C is 3.5hPa. A Henry's law constant of 7.47×10−5 hPa·m3/mol
can be deduced from an experimentally determined equilibrium constant at 25 °C. The partition
coefficient logPOW is measured to −0.85. Since the density of DMF is very similar to
that of water, significant flotation or stratification in surface waters in case of accidental losses
is not expected.
Production Dimethyl formamide is produced either via
a catalyzed reaction of dimethylamine and carbon monoxide in methanol or via the reaction
of methyl formate with dimethylamine. Applications
The primary use of dimethylformamide is as a solvent with low evaporation rate. DMF is
used in the production of acrylic fibers and plastics. It is also used as a solvent in
peptide coupling for pharmaceuticals, in the development and production of pesticides,
and in the manufacture of adhesives, synthetic leathers, fibers, films, and surface coatings.
It is used as a reagent in the Bouveault aldehyde synthesis and in the Vilsmeier-Haack reaction,
another useful method of forming aldehydes. It is also a common catalyst used in the synthesis
of acyl halides, in particular the synthesis of acyl chlorides from carboxylic acids using
oxalyl or thionyl chloride. The catalytic mechanism entails reversible formation of
an imidoyl chloride. DMF penetrates most plastics and makes them
swell. Because of this property DMF is suitable for solid phase peptide synthesis and as a
component of paint strippers. DMF is used as a solvent to recover olefins
such as 1,3-butadiene via extractive distillation. It is also used in the manufacturing of solvent
dyes as an important raw material. It is consumed during reaction.
Pure acetylene gas cannot be compressed and stored without the danger of explosion. Industrial
acetylene gas is, therefore, dissolved in dimethylformamide and stored in metal cylinders
or bottles. The casing is also filled with agamassan, which renders it safe to transport
and use. Niche uses
As a common and cheap reagent, DMF has many uses in the research laboratory.
DMF is effective at separating and suspending carbon nanotubes, and is recommended by the
NIST for use in near infrared spectroscopy of such.
DMF can be utilized as a standard in proton NMR allowing for a quantitative determination
of an unknown compound. In the synthesis of organometallic compounds,
it is used as a source of carbon monoxide ligands.
DMF is a common solvent used in electrospinning. Safety
Reactions including the use of sodium hydride in DMF as a solvent are somewhat hazardous;
exothermic decompositions have been reported at temperatures as low as 26 °C. On a laboratory
scale any thermal runaway is quickly noticed and brought under control with an ice bath
and this remains a popular combination of reagents. On a pilot plant scale, on the other
hand, several accidents have been reported. Toxicity
DMF has been linked to cancer in humans, and it is thought to cause birth defects. In some
sectors of industry, women are banned from working with DMF. For many reactions, it can
be replaced with dimethyl sulfoxide. Most manufacturers of DMF list 'Life' or 'Chronic'
as a health hazard in their MSDS since DMF is not readily disposed of by the body. According
to IARC, DMF is a possible carcinogen, although EPA does not consider it a cancer risk.
References
External links International Chemical Safety Card 0457
NIOSH Pocket Guide to Chemical Hazards 0226 Dimethylformamide usage on Organic Syntheses
Concise International Chemical Assessment Document 31: N,N-Dimethylformamide
Material Safety Data Sheet for DMF DMF Chronic Toxicity Summary
Dimethylformamide Technical Specs from BASF(pdf) DMF GHS MSDS from NuGenTec