Hydroxylamine Sulfate

Hydroxylamine Sulfate is the stable, solid sulfate salt of hydroxylamine, a small, highly reactive nitrogen-oxygen compound that is itself far too unstable and prone to explosive decomposition to store or transport as the free base; forming the sulfate salt is what makes hydroxylamine chemistry practical to handle at industrial scale. Its defining reactivity is forming oximes from ketones and aldehydes — the nitrogen atom of hydroxylamine condenses with the carbonyl carbon, releasing water and leaving a C=N-OH oxime group in place of the original C=O — a transformation that sits at the very start of one of the chemical industry's highest-volume downstream products.

At room temperature it is a white, crystalline, freely water-soluble solid, supplied and handled as an aqueous solution in much of its industrial use given how it is consumed in solution-phase reactions. It is a mild reducing agent and oxidising agent depending on reaction partner, and like hydroxylamine itself, it should be treated with care around strong oxidisers given the nitrogen-oxygen bond's underlying reactivity.

Where it fits in the value chain

Hydroxylamine Sulfate's largest single industrial use, by a wide margin, is reacting with cyclohexanone to form cyclohexanone oxime, the direct precursor that then undergoes the acid-catalysed Beckmann rearrangement to produce caprolactam — the monomer for Nylon 6 that we supply elsewhere in our catalogue. This single reaction chain accounts for the great majority of global hydroxylamine demand. Beyond that core use, the same oxime-forming reactivity is used across pharmaceutical and agrochemical fine-chemical synthesis wherever an oxime intermediate is a required synthetic step, and in smaller volume as a reducing agent in certain analytical and specialty chemical applications.

Grades we supply

Chelora Chemicals offers Hydroxylamine Sulfate in technical/industrial grade suited to caprolactam and other large-volume oxime-forming reactions, and a higher-purity grade with tighter iron and trace-metal control for pharmaceutical and fine-chemical intermediate synthesis. Each grade is supplied with a batch-wise certificate of analysis.

Hydroxylamine Sulfate is produced industrially by one of several routes, the most common being the catalytic reduction of nitric oxide or nitrous acid-derived nitrogen species with hydrogen over a platinum catalyst in a sulphuric acid medium, which forms hydroxylamine directly as its sulfate salt in the same reaction vessel it will later be stored and shipped in, avoiding the need to isolate free hydroxylamine at any point. An alternative, older route reduces nitrate or nitrite salts electrolytically, or via a sulphur dioxide/nitric oxide reduction (the Raschig process), again forming the sulfate (or related ammonium) salt directly rather than isolating the free base.

Because free hydroxylamine itself is markedly unstable and can decompose explosively above a moderate concentration or temperature, every commercial production route is designed specifically to form and retain the stable sulfate (or equivalent) salt from the earliest practical point in the process, with the free base never isolated or shipped as such. The crystalline product is recovered from the reaction mixture by evaporation and crystallisation, then dried and screened to the target particle size.