Sulfamic acid is a molecular formula compound, the molecular formula is H3NSO3. This colorless water-soluble compound has many applications. Sulfamic acid melts at 205 °C and then decomposes at higher temperatures into water, sulfur trioxide, sulfur dioxide and nitrogen gas.
Sulfamic acid (H3NSO3) can be thought of as an intermediate compound between sulfuric acid (H2SO4) and sulfa (H4N2SO2), effectively replacing the hydroxyl (-OH) group with the amine (-NH2) group at each step. This mode cannot be extended further in either direction without destroying the sulfonyl (-SO2-) portion. Sulfamate is a derivative of sulfamate.
Sulfamic acid is produced industrially by treating urea with a mixture of sulfur trioxide and sulfuric acid (or fuming sulfuric acid). The transformation is carried out in two stages, the first being sulfonation:
OC(NH2)2 + SO3 → OC(NH2)(NHSO3H)
OC(NH2)(NHSO3H) + H2SO4 → CO2 + 2 H3NSO3
As a result, some 96,000 tons were produced in 1995.
Sulfamic acid is primarily a precursor of sweet compounds. It reacts with cyclohexylamine, and then NaOH is added to get C6H11NHSO3Na, cyclamate. Related compounds are also sweeteners, such as potassium acetosulfonate.
Sulfonates have been used in the design of a wide range of therapeutic agents, such as antibiotics, nucleoside/nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitors, HIV protease inhibitors (PI), anticancer drugs (steroid sulfase and carbonic anhydrase inhibitors), antiepileptic drugs and weight-loss drugs.
Sulfamic acid is used as an acid cleaner and scale remover, sometimes pure or as an ingredient in proprietary mixtures, and is commonly used in metals and ceramics. For cleaning purposes, there are different grades depending on the application, such as GP grade, SR grade, and TM grade. Often used for rust removal, scale removal, instead of more volatile, more irritating hydrochloric acid, the price is cheaper. It is often used as an ingredient in household scale removers, for example, lime-A-way thick gels containing up to 8% sulfamic acid with A pH of 2.0 -- 2.2, or cleaners used to remove scale. Compared with most common strong inorganic acids, sulfamic acid has ideal water descaling properties, low volatility and low toxicity. It forms a water-soluble salt of calcium and iron trivalent.
Because of its inherent safety, sulfamic acid is superior to hydrochloric acid in home use. If inadvertently mixed with a bleach based product like hypochlorite, it won't form chlorine gas, as the most common acids do; As described in the previous section, the reaction (neutralization) with ammonia produces salt.
