Hydroxylamine Sulfate CAS 10039-54-0

What is Hydroxylamine Sulfate?

Hydroxylamine sulfate is the stable salt form of hydroxylamine — two hydroxylamine molecules held by one sulphuric acid, (NH₂OH)₂·H₂SO₄. Free hydroxylamine is thermally unstable and dangerous to store, so the industry buys the sulphate salt and liberates the reagent in situ with base. That is the entire commercial logic of the product.

It is a white crystalline solid, highly soluble in water, giving a strongly acidic solution. It decomposes rather than melting cleanly, with exothermic decomposition beginning in the region of 120–170 °C depending on purity and on what else is present. Trace metals, particularly iron and copper, lower that onset temperature measurably.

Chemically it is a nucleophile with a nitrogen-oxygen bond, and almost everything it is used for follows from one reaction: condensation with a carbonyl group to give an oxime. Oximes are then rearranged, reduced, cyclised or hydrolysed onward, which puts hydroxylamine sulfate at the start of a surprising number of synthetic routes.

Commercially it is a mid-volume intermediate. The largest single consumer historically is caprolactam manufacture via cyclohexanone oxime, with substantial additional demand from pharmaceutical synthesis, agrochemicals, rubber chemicals, photographic chemistry and metal surface treatment.

Why hydroxylamine sulfate specifically

• A storable form of an unstable reagent. Free hydroxylamine cannot be shipped or warehoused safely at scale. The sulphate salt can, and releases the reagent exactly when and where you want it.
• Clean, high-yielding oxime formation. Condensation with aldehydes and ketones is fast, predictable and usually near-quantitative, which is why it is the default across API and agrochemical synthesis.
• Entry to several ring systems. Oximes cyclise to isoxazoles, amidoximes close to oxadiazoles, and the Beckmann rearrangement converts them to amides and lactams.
• Economical relative to the hydrochloride. For most uses the sulphate is the cheaper salt on an available-hydroxylamine basis — the choice between it and the hydrochloride usually comes down to whether sulphate or chloride is tolerable in your work-up.

How HAS is Manufactured

Hydroxylamine sulfate is made by reducing a nitrogen oxide or nitrite to the hydroxylamine oxidation state and trapping the product as the sulphate salt. Two routes carry most of the world's production.

• Raschig process. Ammonium nitrite is reduced with sulphur dioxide or bisulphite to hydroxylamine disulphonate, which is then hydrolysed under acidic conditions to hydroxylamine sulphate. The oldest route and still widely operated.
• Catalytic hydrogenation of nitric oxide. Nitric oxide is hydrogenated over a platinum catalyst in dilute sulphuric acid, giving hydroxylamine sulphate directly. Cleaner, with a lower ammonium sulphate burden.
• Nitromethane hydrolysis. A smaller route hydrolysing nitroalkanes, used where that feedstock stream is available.
• Crystallisation and drying. The product is crystallised from the acidic liquor, centrifuged, washed and dried at controlled temperature — drying is the step where thermal stability becomes a live process safety question rather than a theoretical one.

Typical Commercial Specification

Figures below are representative of standard commercial grade. Pharmaceutical and low-iron grades with tighter limits are available — send us the specification you work to and we will quote against it.

Physical & Chemical Properties

Reactivity in practice

A nucleophile that is also a reducing agent, delivered from a stable acidic salt. Three reactions account for most of the demand:

• Oxime formation. Condensation with aldehydes and ketones gives aldoximes and ketoximes, usually in high yield under mild buffered conditions.
• Beckmann rearrangement downstream. Ketoximes rearrange under acid to amides and lactams — the step that turns cyclohexanone oxime into caprolactam.
• Amidoxime and heterocycle formation. Reaction with nitriles gives amidoximes, which close to 1,2,4-oxadiazoles; oximes themselves cyclise to isoxazoles and isoxazolines.
• Reduction. It acts as a mild reducing agent in metal surface treatment, photographic chemistry and some dye processes.
• Decomposition under base. Liberating free hydroxylamine with base is the intended first step of most uses — and also the point at which the process becomes thermally sensitive, because free hydroxylamine is the unstable species.

Hydroxylamine Sulfate vs the Hydrochloride and Free Base

Hydroxylamine reaches the market in three forms, and the choice between them is usually decided by your work-up chemistry and your safety case rather than by the hydroxylamine itself.

Stated plainly: the sulphate and the hydrochloride do the same chemistry, and the anion is the decision. Free hydroxylamine solution removes the salt burden but brings a thermal stability problem into your storage rather than leaving it with the supplier, which is why most plants buy the salt and liberate the reagent in the vessel.

Industries We Supply HAS To

The same white crystalline solid goes to an API plant, a herbicide works and a surface treatment line. What changes between them is the grade, the metals limit and the dangerous-goods paperwork each destination expects.

Where HAS is Used

Hydroxylamine sulfate is bought almost entirely for one reaction and its consequences. These are the end uses our customers buy it for.

In pharmaceutical oxime chemistry

The oxime fragment turns up repeatedly in modern APIs — in the methoxyimino side chains of several cephalosporins, in antifungal and cardiovascular intermediates, and as a staging point on the way to amines and amides. Hydroxylamine sulfate is the usual reagent because the condensation is reliable and because the salt is storable. API users typically specify trace metals tightly, partly for elemental impurity control and partly because of the thermal stability issue.

In heterocyclic and agrochemical synthesis

Oximes and amidoximes are the entry point to isoxazole, isoxazoline and oxadiazole rings, all of which appear widely in crop protection actives. Agrochemical buyers are generally less demanding on metals than pharmaceutical buyers and more sensitive on price and on ammonium sulphate content, because the diluent directly affects how much they have to charge.

In caprolactam and industrial use

Cyclohexanone oxime, made from cyclohexanone and hydroxylamine, rearranges under acid to caprolactam for nylon 6. This is the largest single historical use and it operates on a scale where the hydroxylamine is often made on site rather than bought — which is why the merchant market is dominated by the smaller, higher-specification pharmaceutical and agrochemical demand.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis. The methods behind the numbers are standard across the industry, and we are happy to share them or to work to your own in-house test protocol.

• Assay — iodometric titration against the available hydroxylamine, which is the number your charge calculation actually depends on.
• Free acidity — titration. It determines how much base you need to liberate the reagent, and an unexpected shift changes your stoichiometry.
• Ammonium sulphate — the main diluent from the synthesis route, and the usual explanation for a yield that drifts without an obvious impurity.
• Iron and heavy metals — a safety specification as much as a purity one, because trace metals lower the decomposition onset.
• Water insoluble matter and residue on ignition — inorganic carry-over, relevant where the material is charged as a solution.
• Moisture — the material is mildly hygroscopic and cakes, which is a handling problem before it is a quality one.

Common Process Problems & Likely Causes

When hydroxylamine sulfate causes trouble in a plant, the cause is usually one of a short list of things. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. 25 kg net in laminated HDPE bags with inner liners, or in lined fibre or plastic drums, palletised and shrink-wrapped.
• Storage. Cool, dry, well-ventilated and bunded, away from bases, oxidising agents, nitrites and metal salts. Keep well below any temperature that approaches the decomposition range.
• Thermal separation. Do not store near heat sources, steam lines or in direct sun. The decomposition is exothermic, so a heated mass can sustain itself once started.
• Metal contact. Avoid iron, copper and their alloys in handling and transfer equipment. Metal contact is both a contamination route and a decomposition catalyst.
• Base segregation. Store away from alkalis. Contact with base liberates free hydroxylamine, which is the unstable species — that reaction belongs in a controlled vessel, not on a warehouse floor.
• Moisture. Mildly hygroscopic. Keep liners tied and bags closed; caked material is harder to charge accurately.
• Shelf life. Typically 24 months in unopened original packing under those conditions. Beyond that, re-test assay and free acidity rather than assume.
• Transport classification. Shipped under UN 2865, Hydroxylamine sulphate, Class 8, Packing Group III. Confirm against the current SDS and the shipper's declaration for your destination and mode.

Hazards & Safe Handling

Hydroxylamine sulfate is harmful if swallowed and in contact with skin, is a skin sensitiser, causes serious eye damage and is a suspected carcinogen in several classification systems. It also decomposes exothermically. It must be handled by trained personnel under a proper risk assessment — the current SDS supplied with your consignment is the governing document.

• Thermal stability. This is the defining hazard. Decomposition is exothermic and self-sustaining once started, and the onset temperature is lowered by trace metals and by base. Any process that heats the material or holds it in concentrated solution needs a thermal assessment, not an assumption.
• Base contact. Adding base liberates free hydroxylamine, which is far less stable than the salt. Control the addition rate, the temperature and the mixing — an uncontrolled local excess of base is the classic failure mode.
• Sensitisation. It is a recognised skin sensitiser. Once a worker is sensitised, exposures previously tolerated can provoke a reaction, so preventing first contact matters more than managing repeat contact.
• Carcinogenicity classification. Several jurisdictions apply a suspected-carcinogen classification, which brings specific workplace exposure obligations. Factor it into your own risk assessment.
• PPE and dust control. Chemical-resistant gloves, chemical goggles and respiratory protection where dust is generated. Handle under local exhaust ventilation and avoid free-fall transfers.
• Incompatibilities. Strong bases, oxidising agents, nitrites, chlorinating agents and metal salts, particularly iron and copper.
• Spill response. Avoid raising dust. Sweep or vacuum into a labelled closed container; do not use metal tools that could contaminate the material. Ventilate and wash down afterwards.
• First aid. Remove contaminated clothing, wash skin with plenty of water and soap, flush eyes for at least 15 minutes, and seek medical attention with the SDS to hand. Report any skin reaction, which may indicate developing sensitisation.

Regulatory & Compliance Notes

Hydroxylamine sulfate is an established industrial chemical listed on the major national chemical inventories, and it is a regulated dangerous good in transport. Because obligations differ by territory, volume and use, the notes below are orientation rather than legal advice — confirm your own position with your regulatory adviser before importing.

• Inventory status. Listed on the principal chemical inventories in the major importing regions. Ask us for the inventory confirmation relevant to your destination country.
• Dangerous goods. UN 2865, Class 8, Packing Group III. Packing, marking, labelling and declarations prepared for IMDG (sea) or IATA (air) as appropriate.
• Import registration. Several territories require the importer to hold a registration or notification before a consignment lands. Start that process early — it is the most common cause of delay at destination.
• Carcinogen classification. The suspected-carcinogen classification applied in several jurisdictions triggers specific labelling and workplace exposure obligations.
• Precursor and end-use scrutiny. As a reducing agent with energetic decomposition behaviour, it attracts end-use questions in some territories. Expect to supply a statement of intended use.
• Hazard communication. Supplied with an SDS compliant with the format applicable to your region, and labelled in line with the GHS classification for the product.

We Supply HAS Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Hydroxylamine Sulfate from India to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, dangerous-goods paperwork and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other Indian ports arranged where it suits the routing.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and the UN 2865 dangerous-goods declaration issued as a complete set.
• Flexible volumes. A single bag for laboratory qualification, through LCL consolidations, up to repeat full container loads on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying HAS from Chelora

We are an independent sourcing and supply partner. For hydroxylamine sulfate that means settling two things at enquiry: the trace metals limit your process safety case depends on, and whether your work-up tolerates sulphate — because if it does not, the hydrochloride is the product you actually want.

• Documentation on every lot. Batch-specific COA including assay, free acidity, ammonium sulphate and metals, current SDS and TDS.
• Samples before commitment. Trial quantities for process qualification ahead of a commercial order.
• Quantities. From a single 25 kg bag through to full container loads on contract supply.
• Export experience. Class 8 dangerous-goods documentation, packing and labelling handled for sea and air freight.
• Technical support. Direct access to people who know the chemistry, for questions on stoichiometry, free acidity or thermal behaviour.
• Related reagents. Thionyl chloride, chloroacetyl chloride and the wider pharmaceutical intermediate range from one supplier.

How ordering works

• Send the enquiry. Product, grade or pharmacopoeia standard, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing and a sample COA, normally within one working day.
• Sample and qualify. For first orders or critical applications, we send a trial quantity so your lab can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Production and QC. Material allocated and released against a batch-specific COA, with a pre-shipment sample where the application calls for it.
• Ship and document. Packed, labelled and loaded with the full export document set, and tracked through to arrival.

Related Pharmaceutical Intermediates & Excipients

Buyers of hydroxylamine sulfate usually source several of these alongside it. Consolidating them on one order cuts freight cost and gives you a single point of contact for documentation.