Sulfamic acid is a chemical compound with the molecular formula H3NSO3. It is a colourless, water soluble compound, and is also called by many names such as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid. It is a strong acid. The aqueous state of sulfamic acid is unstable and hydrolyses to ammonium bisulphate. The crystalline solid state of sulfamic acid is stable under ordinary conditions.
Sulfamic acid is produced industrially by the treatment of urea with a mixture of sulphur trioxide and sulphuric acid. This happens in two stages, and each stage can be described in the following way:
OC(NH2)2 + SO3 → OC(NH2)(NHSO3H)
OC(NH2)(NHSO3H) + H2SO4 → CO2 + 2 H3NSO3
Sulfamic acid is mainly a precursor to sweet-tasting compounds and hence it is used as sweeteners in the food industry.
It is used as an acidic cleaning agent, especially for metals and ceramics. It is used to remove rust and lime scale. It is a common household descaling agent. It is also used in industrial cleaning of dairy and brew-house equipment. It is also present in denture cleaners.
The derivatives of sulfamic acid, sulphamates, are used in the design of therapeutic agents such as antibiotics, nucleoside/nucleotide HIV reverse transcriptase inhibitors, HIV protease inhibitors, anti-cancer drugs, anti-epileptic drugs and weight loss drugs.
It is used as a catalyst for esterification process, used in dye and pigment manufacturing, as a herbicide, a coagulator for urea-formaldehyde resins, as an ingredient in fire extinguishing media, as a raw material for ammonium sulfamate, in the pulp and paper industry as a chloride stabilizer, in the synthesis of nitrous oxide by reaction with nitric acid, in electroplating as a counter ion for nickel, and in polishing silver.