Preparation of formamide
To the round bottom 3 liter flask fitted with a Liebig’s condenser which emptied into a filter flask, which, in turn, was attached to a tube through which excess ammonia vapors escaped 1500 ml of dry pure formic acid was placed. Dry ammonia gas was led into the formic acid through a glass tube reaching to the bottom of the flask. During the reaction between ammonia and formic acid the flask should be cooled with ice-water because considerable heat is evolved. The reaction is complete in 15-30 minutes yielding ammonium formate. The the reaction flask is gradually heated and during this process the flow of ammonia gas was not interrupted during the whole process, except the rate of flow was somewhat diminished. When the temperature reaches about 150° C water of decomposition began to distill, meanwhile the temperature was increased gradually to 180° C. At this temperature no more water distilled over and this process can take 4-5 hours to complete yielding liquid brown in color. Higher temperatures should be avoided in order to give the minimum decomposition of formamide as distillate liquid will be very dark brown or even black in color. The liquid was allowed to cool in the stream of ammonia gas and distilled in vacuum. In order to obtain pure formamide it is important to get rid of the volatile decomposition products, particularly the products of hydrolysis, by fractional distillation. From the first distillation of the brown liquid having a freezing point of -1.1° C the yield was 82% of the theoretical yield. By multiply fractional distillations the final pure product was obtained 66% of the theoretical. Formamide has density of 1.13 g/cm³, boils at 210°C.
J. Am. Chem. Soc., 1918, 40 (5), pp 793–796
formamide, carbamaldehyde, Methanamide, Formimidic acid, 75-12-7, Formic acid, amide, Methanoic acid, amide, formamid, Formic amide, Amid kyseliny mravenci [Czech], Amid kyseliny mravenci, NSC 748, Carbamaldehyde, Methanamide, HSDB 88, AI3-15357, CCRIS 6240, UNII-4781T907ZS, CHEBI:16397, Formamide solution, ZHNUHDYFZUAESO-UHFFFAOYSA-N, Amide C1, EINECS 200-842-0, DSSTox_CID_5337, DSSTox_RID_77755, DSSTox_GSID_25337, FORMAMIDE, ULTRA PURE, CAS-75-12-7, carboxamides, imidates, Methanamid, imidoformic acid, Ameisensaeureamid, N-formyl amine, Methanimidic acid, an aliphatic amide, MB8, FORMAMIDE, ACS, HCONH2, C1 o pound degrees ., HYDRANAL-Formamide dry, WLN: ZVH, ACMC-1BIX7, bmse000267, AC1L19UT, HYDRANAL(R)-Formamide dry, KSC379A6T, F5786_SIGMA, F7503_SIGMA, F9037_SIGMA, 295876_ALDRICH, 34724_RIEDEL, 551384_ALDRICH, 611891_ALDRICH, 612707_ALDRICH, 613339_ALDRICH, AC1Q50F9, CHEMBL266160, F7503_SIAL, GTPL4739, NSC748, 34724_FLUKA, 47670_FLUKA, 47671_FLUKA, 47671_SIGMA, CHEBI:37622, CHEBI:48431, CHEBI:52479, CHEBI:65285, CTK2F1420, CTK2H9069, HMDB01536, NSC-748, 551384_FLUKA, 611891_FLUKA, 612707_FLUKA, 613339_FLUKA, MolPort-000-871-972, 47670_SIAL, degrees +/->>u(1/4)xE(c), LTBB002179, 221198_SIAL, 295876_SIAL, Tox21_201942, Tox21_302824, ANW-13591, AKOS009031608, 4781T907ZS, LS-1656, MCULE-4202420620, RTR-037669, NCGC00091516-01, NCGC00091516-02, NCGC00256321-01, NCGC00259491-01, AN-23839, KB-52170, DB-055937, TR-037669, F0045, FT-0083173, FT-0603514, FT-0631311, FT-0637321, C00488, InChI=1/CH3NO/c2-1-3/h1H,(H2,2,3, A838330, I05-0381, 3B3-030383, 1156543-55-3, 1158234-15-1, 23296-41-5, 60100-09-6