Dimethylformamide
Dimethylformamide is an organic compound with the formula (CH)NC(O)H. Commonly abbreviated as DMF (although this initialism is sometimes used for dimethylfuran, or dimethyl fumarate), this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions. Dimethylformamide is odorless, but technical-grade or degraded samples often have a fishy smell due to impurity of dimethylamine. Dimethylamine degradation impurities can be removed by sparging samples with an inert gas such as argon or by sonicating the samples under reduced pressure. As its name indicates, it is structurally related to formamide. DMF  is a polar (hydrophilic) aprotic solvent with a high boiling point. It facilitates reactions that follow polar mechanisms, such as S2 reactions. Structure and properties. As for most amides, the spectroscopic evidence indicates partial double bond character for the C-N and C-O bonds. Thus, the infrared spectrum shows a C=O stretching frequency at only 1675 cm, whereas a ketone would absorb near 1700 cm. DMF is a classic example of a fluxional molecule. The ambient temperature H NMR spectrum shows two methyl signals, indicative of hindered rotation about the (O)C-N bond. At temperatures near 100  °C, the 500 MHz NMR spectrum of this compound shows only one signal for the methyl groups. DMF is miscible with water. The vapour pressure at 20 °C is 3.5 hPa. A Henry's law constant of 7.47 × 10 hPa m mol can be deduced from an experimentally determined equilibrium constant at 25 °C. The partition coefficient log "P" is measured to −0.85. Since the density of DMF (0.95 g cm at 20 °C) is similar to that of water, significant flotation or stratification in surface waters in case of accidental losses is not expected . Reactions. DMF is hydrolyzed by strong acids and bases, especially at elevated temperatures. With sodium hydroxide, DMF converts to formate and dimethylamine. DMF undergoes decarbonylation near its boiling point to give dimethylamine. Distillation is therefore conducted under reduced pressure at lower temperatures. In one of its main uses in organic synthesis, DMF was a reagent in the Vilsmeier–Haack reaction, which is used to formylate aromatic compounds. The process involves initial conversion of DMF to a chloroiminium ion, [(CH)N=CH(Cl)], known as a Vilsmeier reagent, which attacks arenes. Organolithium compounds and Grignard reagents react with DMF to give aldehydes  after hydrolysis in a reaction named after Bouveault. Dimethylformamide forms 1:1 adducts with a variety of Lewis acids such as the soft acid I, and the hard acid phenol. It is classified as a hard Lewis base and its ECW model base parameters are E= 2.19 and C= 1.31. Its relative donor strength toward a series of acids, versus other Lewis bases, can be illustrated by C-B plots. Production. DMF was first prepared in 1893 by the French chemist Albert Verley (8 January 1867 – 27 November 1959), by distilling a mixture of dimethylamine hydrochloride and potassium formate. DMF is  prepared by combining methyl formate and dimethylamine or by reaction of dimethylamine with carbon monoxide. Although currently impractical, DMF can be prepared from supercritical carbon dioxide using ruthenium-based catalysts. Applications. The primary use of DMF 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. As a cheap and common reagent, DMF has many uses in a research  laboratory. 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 (usually) 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. On the 20 of June 2018, the Danish Environmental Protective Agency published an article about the DMF's use in squishies. The density of the compound in the toy  resulted in all squishes being removed from the Danish market. All squishies were recommended to be thrown out as household waste. Toxicity. The acute LD50 (oral, rats and mice) is 2.2–7.55 g/kg. Hazards of DMF have been examined.