Sulfamic Acid
Sulfamic acid NH2SO3H
Sulfamic acid has been one of the most widely used scavengers of nitrous acid. It reacts, Eq. (128), to give nitrogen and bisulfate ion. It has the 128 advantage of a high solubility in water, for reactions carried out in water, and is often added as the ammonium salt. Kinetic measurements at 0°C [216] and later at 25°C [188] show that there is acid catalysis up to ~0.2 M, thereafter the rate constant is independent of acidity. The results are interpreted in terms of reaction via the sulfamate ion NH2SO3−, and the two sets of results yield values of 0.98 and 1.1 for the pKa of sulfamic acid.