Ammonium sulfamate

Ammonium sulfamate (or ammonium sulphamate) is a white crystalline solid, readily soluble in water. It is commonly used as a broad spectrum herbicide, with additional uses as a compost accelerator, flame retardant and in industrial processes.

Ammonium sulfamate[1]

Names
IUPAC name Ammonium sulfamate
Other names Ammonium sulphamate Ammate herbicide[2] Ammonium amidosulfonate[2]
Identifiers
CAS Number	7773-06-0
3D model (JSmol)	Interactive image
ChemSpider	22890
ECHA InfoCard	100.028.974
KEGG	C18773
PubChem CID	24482
RTECS number	WO6125000
UNII	945C6IU09L
CompTox Dashboard (EPA)	DTXSID5023875
InChI InChI=1S/H3NO3S.H3N/c1-5(2,3)4;/h(H3,1,2,3,4);1H3 Key: GEHMBYLTCISYNY-UHFFFAOYSA-N InChI=1/H3NO3S.H3N/c1-5(2,3)4;/h(H3,1,2,3,4);1H3 Key: GEHMBYLTCISYNY-UHFFFAOYAI
SMILES [O-]S(=O)(=O)N.[NH4+]
Properties
Chemical formula	H6N2O3S
Molar mass	114.125 g/mol
Appearance	White solid hygroscopic
Density	1.8 g/cm^3
Melting point	131 °C (268 °F; 404 K)
Boiling point	160 °C (320 °F; 433 K) (decomposes)
Solubility in water	very soluble
Solubility	soluble in glycerol, glycol, formamide insoluble in methanol, ether, n-octanol
Acidity (pKa)	6
Hazards
Main hazards	Irritant
Safety data sheet	ICSC 1555
NFPA 704 (fire diamond)	0 2 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2000 mg/kg (oral, rat) 3100 mg/kg (oral, mouse) 3900 mg/kg (oral, rat) 5760 mg/kg (oral, mouse)[3]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 15 mg/m^3 (total) TWA 5 mg/m^3 (resp)[2]
REL (Recommended)	TWA 10 mg/m^3 (total) TWA 5 mg/m^3 (resp)[2]
IDLH (Immediate danger)	1500 mg/m^3[2]
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

Manufacture and distribution

It is a salt formed from ammonia and sulfamic acid.

Ammonium sulfamate is distributed under the following tradenames, which are principally herbicidal product names: Amicide, Amidosulfate, Ammate, Amcide, Ammate X-NI, AMS, Fyran 206k, Ikurin, Sulfamate, AMS and Root-Out.

Uses

Herbicide

Ammonium sulfamate is considered to be particularly useful in controlling tough woody weeds, tree stumps and brambles.

Ammonium sulfamate has been successfully used in several major UK projects by organisations like the British Trust for Conservation Volunteers, English Heritage, the National Trust, and various railway, canal and waterways authorities.

Several years ago the Henry Doubleday Research Association (HDRA) (known as Garden Organic), published an article on ammonium sulfamate after a successful set of herbicide trials. Though not approved for use by organic growers it does provide an option when alternatives have failed.

The following problem weeds / plants can be controlled: Japanese Knotweed (Reynoutria japonica, syn. Fallopia japonica), Marestail / Horsetail (Equisetum), Ground-elder (Aegopodium podagraria), Rhododendron ponticum, Brambles, Brushwood, Ivy (Hedera species), Senecio/Ragwort, Honey fungus (Armillaria), and felled tree stumps and most other tough woody specimens.

Compost accelerator

Ammonium sulfamate is used as a compost accelerator. It is especially effective in breaking down the tougher and woodier weeds put onto the compost heap.

Flame retardant

Ammonium sulfamate (like other ammonium salts, e.g. Ammonium dihydrogen phosphate, Ammonium sulfate) is a useful flame retardant.[4] These salt based flame retardants offer advantages over other metal/mineral-based flame retardants in that they are water processable. Their relatively low decomposition temperature makes them suitable for flame retarding cellulose based materials (paper/wood). Ammonium sulfamate (like Ammonium dihydrogen phosphate) is sometimes used in conjunction with Magnesium sulfate or Ammonium sulfate (in ratios of approximately 2:1) for enhanced flame retardant properties.

Other uses

Within industry ammonium sulfamate is used as a flame retardant, a plasticiser and in electro-plating. Within the laboratory it is used as a reagent.

Safety

Ammonium sulfamate is considered to be slightly toxic to humans and animals, making it appropriate for amateur home garden, professional and forestry uses.[5] It is generally accepted to be safe for use on plots of land that will be used for growing fruit and vegetables intended for consumption.

In the United States, the Occupational Safety and Health Administration has set a permissible exposure limit at 15 mg/m³ over an eight-hour time-weighted average, while the National Institute for Occupational Safety and Health recommends exposures no greater than 10 mg/m³ over an eight-hour time-weighted average.[6] These occupational exposure limits are protective values, given the IDLH concentration is set at 1500 mg/m³.[7]

It is also considered to be environmentally friendly due to its degradation to non-harmful residues.

European Union licensing

The pesticides review by the European Union led to herbicides containing ammonium sulfamate becoming unlicensed, and therefore effectively banned, from 2008.[8] This situation arose as the Irish Rapporteur refused to review the data supplied unless it contained details of animal testing on dogs. As there was already substantial animal data within the package supplied the data pack holder felt further tests without substantiation would cause unnecessary animal suffering. Its licence was not withdrawn on grounds of safety or efficacy.

Its availability and use as a compost accelerator is unaffected by the EU's pesticide legislation.

See also

• Sulfamide

References

1. "Archived copy". Archived from the original on 2007-10-13. Retrieved 2007-07-20.CS1 maint: archived copy as title (link) Chemical properties from Sigma-Adrich
2. NIOSH Pocket Guide to Chemical Hazards. "#0030". National Institute for Occupational Safety and Health (NIOSH).
3. "Ammonium sulfamate". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
4. Bidlack, Verne C.; Fasig, Edgar W. (1951) [1951], "10", Paint and Varnish Production Manual, John Wiley & Sons, p. 275
5. "Pesticide Information Profiles : Ammonium sulfamate". EXTOXNET Extension Toxicology Network. files maintained and archived at Oregon State University. June 1996. Retrieved Mar 21, 2010.
6. "Ammonium sulfamate". NIOSH Pocket Guide to Chemical Hazards. Centers for Disease Control and Prevention. April 4, 2011. Retrieved November 18, 2013.
7. "Ammonium sulfamate". Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs). Centers for Disease Control and Prevention. May 1994. Retrieved November 18, 2013.
8. "Amateur products withdrawn from the market containing ammonium sulphamate". Health and Safety Executive. Archived from the original on 2009-11-13. Retrieved Mar 21, 2010.