Sulfamic acid, also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid, is a molecular compound with the formula H3NSO3. This colorless, water-soluble compound finds many applications. Sulfamic acid melts at 205 °C before decomposing at higher temperatures to H2O, SO3, SO2, and N2. |
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, see acesulfame potassium.
1). 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 however cheaper. It is often a component of household descaling agents, for example, Lime-A-Way Thick Gel contains up to 8% sulfamic acid and pH 2 - 2.2, 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, low toxicity. It forms water-soluble salts of calcium and ferric iron.
Importantly, sulfamic acid is preferable to use in household in comparison to hydrochloric acid for its intrinsic safety. If erroneously mixed with hypochlorite based products such as bleach, it does not form chlorine gas, where the most common acids would; the reaction (neutralization) with NH3, produces a salt as depicted in the section above.
Its also finds applications in the industrial cleaning of dairy and brew-house equipment. Although it is considered less corrosive than hydrochloric acid, corrosion inhibitors are often added to commercial cleansers of which it is a component. Some of its domestic use, e.g. Easy-Off, for descaling include home coffee and espresso equipment and in denture cleaners.
2). Others Uses
For descaling agent of:
Cooling towers (air conditioners)
Marine equipment (sea water evaporators)
Oil, gas Wells
Dairy equipment (pipeline milkers, milk evaporators)
Pulp and paper equipment
General industrial equipment (boilers, condensers, heat exchangers, evaporators, etc.)
Bleaching for Pulp
Sulfation and Sulfonation
Dyes and Pigments
Electroforming, Electroplating, and Electrorefining pH Adjustment
Curing Agent for Phenol, Melamine, and Urea Resin
For Manufacture of Bubbling Pipe Cleaner
3. Precaution For Safety Handling and Storage
Water solution of sulfamic acid shows strong acidity. It may cause eye burns, irritation of nose, throat and skin. Avoid contact with eyes skin and clothing. Avoid breathing dust. Wash thoroughly after handling.
Sulfamic acid is not flammable nor explosive itself. But when involved in a fire it may release hazardous gases, such as SO2,SO3,NH3 .
To prevent absorption of moisture and possible caking, store in a cool dry area. Do not expose to high temperature.
4. For Personal Health and Safety
Sulfamic acid in solid form causes virtually no skin irritation, but its aqueous solution may cause corrosive burns like mineral acids. When handling aqueous sulfamic acid solutions, the same safety measures must be taken as dilute sulfuric acid.
Avoid contact with skin or eyes. Cup-type, rubber or soft plastic-framed goggles, protective clothing, and rubber gloves must be worn when handling sulfamic acid either in crystalline or solution form. Avoid breathing dust. Use adequate ventilation. Wash hands thoroughly after handling.
In case of eye contact, immediately flush the eyes with plenty of running water for at least 15 mins. and send the patient to a doctor or hospital. For skin contact, wash the area with plenty of water.
Sulfamic acid is non-flammable and non-explosive and requires no special safety measures during storage. To prevent from the absorbition of moisture and possible caking, it should be stored in a cool, dry place. Exposure to excessive temperature should be avoided.
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