Of formamide

Boil 1 ml. of formamide in a test-tube and note that ammonia is freely evolved. Carbon monoxide is also produced, but cannot usually be ignited in the presence of the ammonia. 

Two Lewis structures (resonance forms) of formamide the atoms are connected in the same order but the arrangment of the electrons is different... 

Formic acid is currently produced iadustriaHy by three main processes (/) acidolysis of formate salts, which are ia turn by-products of other processes (2) as a coproduct with acetic acid ia the Hquid-phase oxidation of hydrocarbons or (3) carbonylation of methanol to methyl formate, followed either by direct hydrolysis of the ester or by the iatermediacy of formamide. 

Tables 1 and 2 Hst the important physical properties of formamide. Form amide is more highly hydrogen bonded than water at temperatures below 80°C but the degree of molecular association decreases rapidly with increa sing temperature. Because of its high dielectric constant, formamide is an excellent ionizing solvent for many inorganic salts and also for peptides, proteias (eg, keratin), polysaccharides (eg, cellulose [9004-34-6] starch [9005-25-8]) and resias.

Table 2. Vapor Pressure of Formamide at Various Temperatures ...

Aqueous solutions of formamide react with formaldehyde [50-00-0] in neutral or alkaline media to yield the dimethylol derivative,... 

In unalloyed steel containers formamide discolors slowly during shipment and storage. Both copper and brass are also subject to corrosion, particularly in the presence of water. Lead is less readily attacked. Aluminum and stainless steel are resistant to attack by formamide and should be used for shipping and storage containers where the color of the product is important or when metallic impurities must be minimized. Formamide attacks natural mbber but not neoprene. As a result of the solvent action of formamide, most protective paints and finishes are unsatisfactory when in contact with formamide. Therefore, formamide is best shipped in containers made of stainless steel or in dmms made of, or coated with, polyethylene. Formamide supphed by BASF is packed in Lupolen dmms (230 kg) or Lupolen canisters (60 kg) both in continental Europe and overseas. 

The estimated capacity of formamide was approximately 100,000 t/yr worldwide in 1990. In 1993, there are only three significant producers BASE in Germany is the leading manufacturer. Smaller quantities of formamide are produced in the former Czechoslovakia (Sokolov) and Japan (Nitto) by direct synthesis from carbon monoxide and ammonia. Most of the formamide produced is utilized direcdy by the manufacturers. The market price for formamide (ca 1993) is about 2.00/kg. 

The quahty of formamide suppHed by BASE is certified as having a minimum assay of 99.5%. The principal impurities in the material are ammonium formate, methanol, water, and traces of iron. The quaUty of formamide supphed by BASE is certified to meet the specifications given in Table 3. 

Direct deterruination of the formamide content by gc methods proves to be inaccurate because of its tendency to decompose at elevated temperatures. This also limits the accuracy of the classical Kjehldahl deterruination. The purity of formamide is, therefore, more reUably deterrnined by analysis of its impurities and substraction of the combined contents from 100%. 

Aromatic and heterocycHc compounds are formylated by reaction with dialkyl- or alkylarylformamides in the presence of phosphoms oxychloride or phosgene (Vilsmeier aldehyde synthesis) (125). The Vilsmeier reaction is a Friedel-Crafts type formylation (126), since the intermediate cation formed by the interaction of phosphoms oxychloride with formamide is a typical electrophilic reagent. Ionic addition compounds of formamide with phosgene or phosphoms oxychloride are also known (127). 

In the Shoe or one-shot method (4), formamide is used to coagulate sodium silicate. The silicate solution used in the Joosten method can be diluted with water to lower its viscosity. Concentrations of sodium silicate between 10—70% are used (viscosities of 2.5—50 mPa-s). Concentrations of formamide are between 2 and 30%. Other reactants such as CaCl2 and sodium aluminate are used in concentrations between 2.4—12 g/L of silicate solution. 

Finally, some results obtained from indazoles substituted in the carbocycle are of interest, even though in these cases the reaction does not involve the heterocyclic moiety (Section 4.04.2.3.2(ii)). For example, pyrazolo[3,4-/]- (566) and pyrazolo[4,3-/]-quinolines (567) have been obtained from aminoindazoles by the Skraup synthesis (76JHC899). Diethylethoxy-methylenemalonate can also be used to give (566 R = C02Et, R = OH) (77JHC1175). Pyrazolo-[4,3-/]- and -[4,3-g]-quinazolones (568) and (569) have been obtained from the reaction of formamide with 5-amino-4-methoxycarbonyl- and 6-amino-5-carboxyindazole, respectively (81CB1624). 

Commercial formamide (E. Merck, Darmstadt) was used. The use of a large excess of formamide with respect to the sulfinate is required in order to obtain the yield specified. ... 

Triazole has been prepared by the oxidation of substituted 1,2,4-triazoles, by the treatment of urazole with phosphorus pentasulfide, by heating equimolar quantities of formyl-hydrazine and formamide, by removal of the amino function of 4-amino-l,2,4-triazole, by oxidation of l,2,4-triazole-3(5)-thiol with hydrogen peroxide, by decarboxylation of 1,2,4-triazole-3(5)-carboxylic acid, by heating hydrazine salts with form-amide,by rapidly distilling hydrazine hydrate mixed with two molar equivalents of formamide, i by heating N,N -diformyl-hydrazine with excess ammonia in an autoclave at 200° for 24 hours, and by the reaction of 1,3,5-triazine and hydrazine monohydrochloride. ... 

The chain addition of formamide to alkenes is a closely related reaction. It results in the formation of primary amides. The reaction is carried out with irradiation in acetone. The photoexcited acetone initiates the chain reaction by abstracting hydrogen from formamide ... 

There is much evidence that there are many cases in which the interaction between liquids and solids cannot be described in terms of dispersion forces alone. For example, Dann [75] found significant non-dispersion-force contributions to the work of adhesion between ethanol/water mixtures, mixed glycols, and polyglycols and a mixture of formamide and 2-ethoxyethanol against a variety of solids. The nature of these other interactions , however, were at first the subject of some dispute. We may account for them in a general way with a term /sl inserted into Eq. 11 ... 

FIGURE 4.50 FVjrifIcation of mRNA on Toyopearl HW-65F. Column Toyopearl HW-65F. 25 mm X 90 cm. Sample 40 mg of poly(A) RNA/5 ml of formamide, sample from silkworm. Elution 20 mA1 sodium citrate, 5 mM EDTA, 0.5% SDS, 6 M urea, pH 3.5. Flow rate 24 ml/hr. Detection UV at 254, total mRNA activity (—), mRNA activity for major plasma proteins (------------). 

Examine the geometry of formamide. Is the CN bond shorter than expected for a normal single bond (in methylamine), and closer to that expected for a full double bond (in methyleneimine) Is the CO bond longer than that expected in a carbonyl compound (in formaldehyde), perhaps closer to that appropriate for a single bond (in methanol) Also, compare the electrostatic potential map for formamide with those of formaldehyde and methylamine. Is the CO bond in formamide more or less polar than that in formaldehyde Is the CN bond in formamide more or less polar than that in methylamine Draw whatever Lewis structures are needed to properly describe the geometry and charge distribution of formamide. 

Good yields of pyrido[2,3-d]pyrimidiries (37) were also oblaiiied by the action of formamide on o-amino nitriles (36). Reduction of 2-amino-4,6-dimethylnicotinitrilc yields the 3-aminomcthyl compound (38). Acylation to the 3-aoylaminomethyl derivative (39), followed by cyolization, by means of heat or phosphoryl chloride, yielded the dihydropyrido[2,3-d]pyrimidines (40). ... 

In the case of l-dimethylaminobut-l-en-3-yne no 4-methylpyrimidine was isolated because its boiling point is close to that of a side product, dimethylfor-mamide. The latter results from transamination of formamide by dimethylamine in the course of cyclization. The pyrimidines 156 were isolated and characterized as picrates (70ZOR1528). For easier isolation of pure 4-methylpyiimidine... 

In the authors opinion (81UK1252), the evidence for such a scheme is the isolation of formamide transamination products, dialkylformamides (in case of l-dialkylaminoalk-l-en-3-ynes). Examples of formamide transamination, e.g., by /3-amino-substituted carbonyl compounds, are known [58CB2832 60CB1402 60HC( 14)272],... 

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