OTC sulfamic acid sample
| IUPAC name
| Systematic IUPAC name
| Other names
|Molar mass||97.10 g/mol|
|Melting point||205 °C (401 °F; 478 K) (decomposes)|
| 14.68 g/100 ml (0 °C)|
18.56 g/100 ml (10 °C)
21.32 g/100 ml (20 °C)
26.09 g/100 ml (30 °C)
29.49 g/100 ml (40 °C)
32.82 g/100 ml (50 °C)
37.10 g/100 ml (60 °C)
41.91 g/100 ml (70 °C)
47.08 g/100 ml (80 °C)
|Solubility|| Moderately soluble in ammonia, DMF, formamide|
Sparingly solubility in methanol, sulfuric acid
Insoluble in acetone, acetonitrile, carbon disulfide, carbon tetrachloride, chloroform, DCM, diethyl ether, ethanol, hydrocarbons
|Solubility in acetone||0.4 g/100 g|
|Solubility in diethyl ether||0.009 g/100 g|
|Solubility in formamide||20 g/100 g|
|Solubility in methanol||4.3 g/100 g|
|Solubility in sulfuric acid||2.38 g/100 g|
|Vapor pressure||~0.06 mmHg (20 °C)|
|Safety data sheet||Sigma-Aldrich|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
| 3,160 mg/kg (rat, oral)|
1,312 mg/kg (mouse, oral)
1,050 mg/kg (guinea pig, oral)
| Sulfuric acid|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Sulfamic acid, also known as amidosulfonic acid, aminosulfonic acid or sulfamidic acid, is a chemical compound with the formula H3NSO3 or H2NSO3H, a solid strong acid at room.
Sulfamic acid is a moderately strong acid, Ka = 0.101 (pKa = 0.995).
Aqueous solutions of sulfamic acid are unstable and slowly hydrolyze to ammonium bisulfate, but the crystalline solid is indefinitely stable under ordinary storage conditions.
- HNO2 + H3NSO3 → H2SO4 + N2 + H2O
- HNO3 + H3NSO3 → H2SO4 + N2O + H2O
Upon heating sulfamic acid will react with alcohols to form the corresponding organosulfates.
- H3NSO3 → H2O + SO3 + SO2 + N2
Sulfamic acid is a colorless odorless solid acid, soluble in water, but insoluble in organic solvents. Sulfamic acid is not hygroscopic, though finely powdered form may appear "sticky", similar to wet snow in appearance.
Sulfamic acid is readily available as solid acidic descaling agent, sold in many hardware stores. Sometimes it's sold as coffee machine cleaning powder, though always read the label, as many have producers have replaced it with citric acid.
- (NH2)2CO + SO3 → OC(NH2)(NHSO3H)
- OC(NH2)(NHSO3H) + H2SO4 → CO2 + 2 H3NSO3
Hydrolysis of sulfamide will yield sulfamic acid.
Preparation of sulfamic acid is not something any amateur chemist can do at home, due to the extreme conditions the preparation requires. As such, it's much more economical to simply purchase the compound, and usually is readily available.
- Make nitrous oxide
- Make methylamine
- Make sodium cyclamate
- Catalyst for esterification process
- Make ammonium bisulfate
- Make ammonium sulfamate
- Make guanidinium sulfate
- Make ammonium dinitramide
- Coagulator for urea-formaldehyde resins
- Silver polishing
Sulfamic acid is irritant and should be handled with care.
Sulfamic acid is best stored in closed plastic bottles, away from ammonia and moisture.
Can be neutralized with an aq. base, then poured down the drain.
- Cupery, M. E.; Industrial and Engineering Chemistry; vol. 30; (1938); p. 627 - 631
- Patron, M.; Ind. chim.; vol. 42; (1955); p. 237 - 243