SULFAMIC ACID

synonyms:
SULFAMIC ACID; Acide sulfamique; acide sulfamidique, acide aminosulfonique, acide amidosulfonique, acide amidosulfurique; SULFAMICACID; 5329-14-6; Amidosulfonic acid; Aminosulfonic acid; Sulphamic acid; Amidosulfuric acid; Imidosulfonic acid; Sulfamidic acid; Sulfaminic acid; Jumbo; Sulphamidic acid; Kyselina amidosulfonova; Caswell No. 809; sulfuramidic acid; NSC 1871; MFCD00011603; Kyselina sulfaminova [Czech]; UNII-9NFU33906Q; Acide sulfamique; Sulfamidic acid; Sulfaminic acid; Jumbo; Sulphamidic acid; Aminosulfuric acid; Kyselina sulfaminov; Kyselina amidosulfonova; Caswell No. 809; sulfuramidic acid; NSC 1871; MFCD00011603; Kyselina sulfaminova [Czech]; UNII-9NFU33906Q; Acide sulfamique;  Aminosulfuric acid; Kyselina sulfaminov; Kyselina amidosulfonova; Caswell No. 809; sulfuramidic acid; NSC 1871; MFCD00011603; Kyselina sulfaminova [Czech]; UNII-9NFU33906Q; Acide sulfamique; SULFAMIC ACID; SULFAMİC ACİD; SULFAMİK ACİD; SÜLFAMİK ACİD; SULFAMİK ACİT  Acide sulfamique; acide sulfamidique, acide aminosulfonique, acide amidosulfonique, acide amidosulfurique; SULFAMICACID; 5329-14-6; Amidosulfonic acid; Aminosulfonic acid; Sulphamic acid; Amidosulfuric acid; Imidosulfonic acid; Sulfamidic acid; Sulfaminic acid; Jumbo; Sulphamidic acid; Aminosulfuric acid; Kyselina sulfaminov; Kyselina amidosulfonova;sulfuramidic acid; NSC 1871; MFCD00011603; Kyselina sulfaminova [Czech]; UNII-9NFU33906Q; Acide sulfamique; SULFAMIC ACID; SULFAMİC ACİD; SULFAMİK ACİD; SÜLFAMİK ACİD; SULFAMİK ACİT; sülfamic asit; sülfamique acide; sulfamik asid; sülfamik asid; Acide sulfamique; Acide Sulfamique

Sulfamic acid

Sulfamic acid
Tautomerism of sulfamic acid
Ball-and-stick model of the canonical neutral form
Ball-and-stick model of the zwitterionic form
Sample of sulfamic acid.jpg
Names
IUPAC name
Sulfamic acid
Identifiers
CAS Number    
5329-14-6 check
3D model (JSmol)    
Interactive image
zwitterion: Interactive image
ChEBI    
CHEBI:9330 check
ChEMBL    
ChEMBL68253 check
ChemSpider    
5767 check
ECHA InfoCard    100.023.835 Edit this at Wikidata
EC Number    
226-218-8
PubChem CID    
5987
RTECS number    
WO5950000
UNII    
9NFU33906Q check
UN number    2967
CompTox Dashboard (EPA)    
DTXSID6034005 Edit this at Wikidata
InChI[show]
SMILES[show]
Properties
Chemical formula    H3NSO3
Molar mass    97.10 g/mol
Appearance    white crystals
Density    2.15 g/cm3
Melting point    205 °C (401 °F; 478 K) decomposes
Solubility in water    Moderate, with slow hydrolysis
Solubility    
Moderately soluble in DMF
Slightly soluble in MeOH
Insoluble in hydrocarbons
Acidity (pKa)    1.0[1]
Hazards
Safety data sheet    ICSC 0328
EU classification (DSD) (outdated)    Irritant (Xi)
R-phrases (outdated)    R36/38 R52/53
S-phrases (outdated)    (S2) S26 S28 S61
Related compounds
Other cations    Ammonium sulfamate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Sulfamic acid, also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid, is a molecular compound with the formula H3NSO3. This colourless, water-soluble compound finds many applications. Sulfamic acid melts at 205 °C before decomposing at higher temperatures to water, sulfur trioxide, sulfur dioxide and nitrogen.[2]

Sulfamic acid (H3NSO3) may be considered an intermediate compound between sulfuric acid (H2SO4), and sulfamide (H4N2SO2), effectively replacing a hydroxyl (–OH) group with an amine (–NH2) group at each step. This pattern can extend no further in either direction without breaking down the sulfonyl (–SO2–) moiety. Sulfamates are derivatives of sulfamic acid.

Production
Sulfamic acid is produced industrially by treating urea with a mixture of sulfur trioxide and sulfuric acid (or oleum). The conversion is conducted in two stages:

OC(NH2)2 + SO3 → OC(NH2)(NHSO3H)
OC(NH2)(NHSO3H) + H2SO4 → CO2 + 2 H3NSO3
In this way, approximately 96,000 tonnes were produced in 1995.[3]

Structure and reactivity

Ball-and-stick model of a sulfamic acid zwitterion as it occurs in the crystal state.[4]
The compound is well described by the formula H3NSO3, not the tautomer H2NSO2(OH). The relevant bond distances are 1.44 Å for the S=O and 1.77 Å for the S–N. The greater length of the S–N is consistent with a single bond.[5] Furthermore, a neutron diffraction study located the hydrogen atoms, all three of which are 1.03 Å distant from the nitrogen.[4] In the solid state, the molecule of sulfamic acid is well described by a zwitterionic form.

Aqueous solutions of sulfamic acid are unstable and slowly hydrolyse to ammonium bisulfate, but the crystalline solid is indefinitely stable under ordinary storage conditions. Its behaviour resembles that of urea, (H2N)2CO. Both feature amino groups linked to electron-withdrawing centres that can participate in delocalised bonding. Both liberate ammonia upon heating in water ; however, the sulfamic acid reverts back to sulfuric acid , in place of the CO2 that urea would release , according to the following reaction :

H3NSO3 + H2O → H2SO4 + NH3
Acid–base reactions
Sulfamic acid is a moderately strong acid, Ka = 0.101 (pKa = 0.995). Because the solid is not hygroscopic, it is used as a standard in acidimetry (quantitative assays of acid content).

H3NSO3 + NaOH → NaH2NSO3 + H2O
Double deprotonation can be effected in ammonia solution to give the anion HNSO2−
3.[6]

H3NSO3 + 2 NH3 → HNSO2−
3 + 2 NH+
4
Reaction with nitric and nitrous acids
With nitrous acid, sulfamic acid reacts to give nitrogen:

HNO2 + H3NSO3 → H2SO4 + N2 + H2O
while with nitric acid, it affords nitrous oxide:[7]

HNO3 + H3NSO3 → H2SO4 + N2O + H2O
Reaction with hypochlorite
The reaction of excess hypochlorite ions with sulfamic acid or a sulfamate salt gives rise reversibly to both N-chlorosulfamate and N,N-dichlorosulfamate ions.[8][9][10]

HClO + H2NSO3H → ClNHSO3H + H2O
HClO + ClNHSO3H ⇌ Cl2NSO3H + H2O
Consequently, sulfamic acid is used as hypochlorite scavenger in the oxidation of aldehydes with chlorite such as the Pinnick oxidation.

Reaction with alcohol
Upon heating sulfamic acid will react with alcohols to form the corresponding organosulfates. It is more expensive than other reagents for doing this, such as chlorosulfonic acid or oleum, but is also significantly milder and will not sulfonate aromatic rings. Products are produced as their ammonium salts. Such reactions can be catalyzed by the presence of urea.[10]

ROH + H2NSO3H → ROS(O)2O− + NH+
4
Without the presence of any catalysts , sulfamic acid will not react with ethanol at temperatures below 100 °C .

Applications
Sulfamic acid is mainly a precursor to sweet-tasting compounds. Reaction with cyclohexylamine followed by addition of NaOH gives C6H11NHSO3Na, sodium cyclamate. Related compounds are also sweeteners, such as acesulfame potassium.

Sulfamates have been used in the design of many types of therapeutic agents such as antibiotics, nucleoside/nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitors, HIV protease inhibitors (PIs), anticancer drugs (steroid sulfatase and carbonic anhydrase inhibitors), antiepileptic drugs, and weight loss drugs.[11]

Cleaning agent
Sulfamic acid is used as an acidic cleaning agent, sometimes pure or as a component of proprietary mixtures, typically for metals and ceramics. It is frequently used for removing rust and limescale, replacing the more volatile and irritating hydrochloric acid, which is cheaper. It is often a component of household descaling agents, for example, Lime-A-Way Thick Gel contains up to 8% sulfamic acid and has pH 2.0–2.2,[12] or detergents used for removal of limescale. When compared to most of the common strong mineral acids, sulfamic acid has desirable water descaling properties, low volatility, and low toxicity. It forms water-soluble salts of calcium and ferric iron.

Sulfamic acid is preferable to hydrochloric acid in household use, due to its intrinsic safety. If erroneously mixed with hypochlorite based products such as bleach, it does not form chlorine gas, whereas the most common acids would; the reaction (neutralisation) with ammonia, produces a salt, as depicted in the section above.

It also finds applications in the industrial cleaning of dairy and brewhouse equipment. Although it is considered less corrosive than hydrochloric acid, corrosion inhibitors are often added to the commercial cleansers of which it is a component. It can be used for descaling home coffee and espresso machines and in denture cleaners.

Other uses
Catalyst for esterification process
Dye and pigment manufacturing
Herbicide
Coagulator for urea-formaldehyde resins
Ingredient in fire extinguishing media. Sulfamic acid is the main raw material for ammonium sulfamate which is a widely used herbicide and fire retardant material for household products.
Pulp and paper industry as a chloride stabilizer
Synthesis of nitrous oxide by reaction with nitric acid
The deprotonated form (sulfamate) is a common counterion for nickel(II) in electroplating.
Used to separate nitrite ions from mixture of nitrite and nitrate ions( NO3−+ NO2−) during qualitative analysis of nitrate by Brown Ring test.
Silver polishing
According to the label on the consumer product, the liquid silver cleaning product TarnX contains thiourea, a detergent, and sulfamic acid.

Help on calculated properties New window
Property name Property value Reference
Molecular weight of Sulfamic acid: 97.1 g / mol calculated by PubChem 2.1 (PubChem release 2019.06.18)
XLogP3-AA -1.6 calculated by XLogP3 3.0 (PubChem release 2019.06.18)
Number of sulfamic acid hydrogen bond donors: 2 calculated by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Number of hydrogen bond acceptors of Sulfamic acid: 4 calculated by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Number of rotary bonds of sulfamic acid: 0 calculated by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Exact mass of Sulfamic acid: 96.983364 g / mol calculated by PubChem 2.1 (PubChem release 2019.06.18)
Monoisotopic mass of Sulfamic acid: 96.983364 g / mol calculated by PubChem 2.1 (PubChem release 2019.06.18)
Topological polar surface of Sulfamic acid: 88.8 Ų calculated by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Number of heavy atoms of sulfamic acid: 5 calculated by PubChem
Formal charge of Sulfamic acid: 0 calculated by PubChem
Complexity of Sulfamic Acid: 92.6 calculated by Cactvs 3.4.6.11 (PubChem version 2019.06.18)
Number of isotopic atoms of Sulfamic acid: 0 calculated by PubChem
Defined number of atomic stereocenters of Sulfamic Acid: 0 calculated by PubChem
Number of undefined atomic stereocenter of Sulfamic acid: 0 calculated by PubChem
Defined number of Sulfamic Acid bond stereocenters: 0 calculated by PubChem
Number of undefined binding stereocentre of Sulfamic Acid: 0 calculated by PubChem
Number of covalently bound units of Sulfamic Acid: 1 calculated by PubChem
The compound is canonized from Sulfamic Acid: Yes

Sulfamic acid appears as a white crystalline solid. Density 2.1 g / cm3. Melting point 205°C. Combustible. Irritates skin, eyes, and mucous membranes. Low toxicity. Used to make dyes and other chemicals.

CAMEO Chemicals
Sulfamic acid is the simplest of the sulfamic acids consisting of a single sulfur atom covalently bound by single bonds to hydroxy and amino groups and by double bonds to two oxygen atoms.

Sulfamic acid is a water-soluble, moderately strong acid. An intermediate between sulfuric acid and sulfamide, it can be used as a precursor to sweet-tasting compounds, a therapeutic drug component, an acidic cleaning agent, and a catalyst for esterification.