Synthesis of semicarbazide hydrochloride

Preparation of semicarbazide hydrochloride

130 g hydrazine sulfate and 54 g sodium carbonate are dissolved in 50 ml of water. The solution is warmed to 50-60°C and 86 g potassium cyanate dissolved in 500 ml water is slowly added. The next day the reaction mixture is filtered, and filtrate is treated with 120 g of acetone. The solution with frequent shaking is left for another 24 hours. The small amount of precipitations are filtered and mother liquor is evaporated to dryness. The dry residue is extracted with Soxhlet extractor using ethyl alcohol as a solvent. The acetone-semicarbazone crystallizes in the distilling flask of the extraction apparatus. The ethyl alcohol is removed and residue is washed with a little alcohol and ether. The yield is 80% with melting point 186-187° C. Acetone-semicarbazone is transformed quantitatively into semicarbazide hydrochloride, by gently warming 11.5 g of semicarbazone with 10 g concentrated hydrochloric acid. During the hydrolysis the semicarbazone is completely dissolved, which on cooling solidifies to a thick paste of colorless, well-formed needles. Semicarbazide hydrochloride is filtered and washed with little alcohol and ether. From the mother-liquor, by adding double its volume of alcohol and ether, some more semicarbazide hydrochloride could be obtained. Semicarbazide hydrochloride melts at 173° with decomposition.

Laboratory methods of inorganic chemistry by H. Biltz, 11, 1928





InChI Key


Canonical SMILES


Depositor-Supplied Synonyms

SEMICARBAZIDE HYDROCHLORIDE, 563-41-7, Semicarbazide HCl, Aminourea hydrochloride, hydrazinecarboxamide hydrochloride, Semicarbazide chloride, Amidourea hydrochloride, Carbamylhydrazine hydrochloride, Semicarbazide monohydrochloride, Semicarbazide, monohydrochloride, Carbamyl hydrazine.HCl, Hydrazine carboxamide hydrochloride, Hydrazinecarboxamide, hydrochloride, Hydrazinecarboxamide monohydrochloride, EK 226, Hydrazinecarboxamide, monohydrochloride, Semicarbazide, hydrochloride, CCRIS 556, CHEBI:82532, HSDB 5197, Semicarbazide hydrochloride (VAN), NSC 4732, EINECS 209-247-0, Hydrazinecarboxamide, hydrochloride (VAN), AI3-52680, N-Aminourea hydrochloride, Hydrazinecarboxamide, hydrochloride (1:1), PubChem15701, DSSTox_CID_244, Semikarbazide hydrochloride, ACMC-1B0NX, WLN: ZVMZ &GH, Aminourea hydrochloride, semi-carbazide hydrochloride, AC1L1WX1, SCHEMBL6932, S2201_ALDRICH, DSSTox_RID_75458, DSSTox_GSID_20244, KSC490O3N, MLS002153236, 57-56-7 (Parent), hydrochloric acid semicarbazide, 33656_RIEDEL, CHEMBL1256355, UNII-34854VG84B, 33656_FLUKA, 84940_FLUKA, CTK3J0736, NSC4732, hydrazinecarbox-amide hydrochloride, MolPort-001-757-400, XHQYBDSXTDXSHY-UHFFFAOYSA-N, BB_SC-7175, NSC-4732, Tox21_200950, ANW-32488, EBD568260, AKOS015848282, 34854VG84B, CCG-222400, LP01096, LS-1382, MP-2143, RP19032, RTC-064162, NCGC00091589-01, NCGC00094369-01, NCGC00258503-01, AK116147, AN-23700, CAS-563-41-7, KB-60429, SC-16469, SC-47308, SMR000326716, AB0010803, ST2413115, TC-064162, EU-0101096, S0032, C19521, S 2201

Removed Synonyms

Semicarbazide, CID11236, S-2460

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