Nitrosylsulfuric Acid
The Nitrosylsulfuric Acid supplied by Chelora Chemicals — a non-aqueous nitrosating and diazotising reagent central to hydroxylamine sulfate and dye-intermediate manufacture — exported from Indonesia in specialised moisture-proof packaging with full batch documentation on every shipment.
What Nitrosylsulfuric Acid is, and why buyers source it
A working overview of the reagent's chemistry, how it provides nitrosating power without the water that would otherwise accompany it, and the role it plays in hydroxylamine sulfate and dye-intermediate manufacture.
Nitrosylsulfuric Acid is formed by absorbing nitrogen oxide gases into concentrated sulfuric acid or oleum, producing a compound that delivers the reactive nitrosonium (NO+) species in a non-aqueous, strongly acidic medium — a combination that is often exactly what a nitrosation or diazotisation reaction needs but that the more familiar aqueous sodium nitrite/mineral acid combination cannot provide, since that classic method necessarily introduces water into the reaction that nitrosylsulfuric acid's anhydrous chemistry avoids entirely. Avoiding free water in a nitrosation reaction matters whenever the substrate, intermediate or desired product would otherwise hydrolyse, decompose or react unfavourably with the water a conventional nitrite-based method brings along with it.
At room temperature it is a white to pale yellow solid that melts to a liquid a little above typical ambient temperature, and it is commonly supplied, handled and used either in its solid/molten form or as a solution in sulfuric acid, depending on the buyer's own process. It reacts with water, releasing nitrous acid (which itself decomposes further into nitrogen oxide gases) and sulfuric acid, a reaction that must be managed carefully given both the corrosivity of the sulfuric acid released and the toxicity of the nitrogen oxide gases.
Where it fits in the value chain
Nitrosylsulfuric Acid's most consequential industrial role, closely tied to our own catalogue, is as a key intermediate species in one classical route to hydroxylamine sulfate (the oxime-forming reagent we supply separately, itself the precursor to caprolactam via the Beckmann rearrangement): nitric oxide absorbed into sulfuric acid to form nitrosylsulfuric acid is subsequently reduced to hydroxylamine sulfate in the Raschig-Hooker process. Independently of that route, nitrosylsulfuric acid is also used directly as a non-aqueous diazotising agent in dye and pigment intermediate synthesis, and in certain other nitrosation reactions across fine-chemical manufacture where anhydrous conditions are specifically required.
Grades we supply
Chelora Chemicals offers Nitrosylsulfuric Acid in technical grade, supplied as solid/molten material or as a sulfuric acid solution according to the buyer's process requirement. Each grade is supplied with a batch-wise certificate of analysis.
How Nitrosylsulfuric Acid is produced
An overview of the production route for orientation purposes. Our manufacturing partners' own process parameters and in-process controls are proprietary and are not disclosed beyond what is needed to interpret the certificate of analysis.
Nitrosylsulfuric Acid is produced by absorbing nitrogen oxide gases — typically a mixture of nitric oxide and nitrogen dioxide, generated by the catalytic oxidation of ammonia or by reduction of nitric acid — into concentrated sulfuric acid or oleum, where the nitrogen oxide reacts directly with the acid medium to form the nitrosylsulfuric acid compound. The ratio and oxidation state of the nitrogen oxides absorbed, together with the strength of the absorbing acid, are the main process variables controlling conversion efficiency and final product purity.
This absorption chemistry has a long industrial history, having originally been central to the lead-chamber process for sulfuric acid manufacture before the more efficient contact process superseded it; today the same underlying chemistry is run in dedicated, purpose-built absorption systems specifically to produce nitrosylsulfuric acid itself as the target product, most significantly as an intermediate step toward hydroxylamine sulfate manufacture. The product is recovered, depending on the intended use and shipping form, either as a solution in sulfuric acid or, after further concentration, as the solid/molten compound.
Industries and processes that use it
Nitrosylsulfuric Acid is consumed predominantly as a key intermediate toward hydroxylamine sulfate manufacture, with further use in dye-intermediate diazotisation and other anhydrous nitrosation chemistry. The fields below account for most of the demand we see through our export desk.
Hydroxylamine Sulfate Manufacture (Raschig-Hooker Process)
Serves as the key nitrogen-oxide-carrying intermediate that is subsequently reduced to hydroxylamine sulfate, the oxime-forming reagent behind the caprolactam/Nylon 6 route.
Non-Aqueous Diazotisation
Used as a diazotising agent for aromatic amines under anhydrous conditions, avoiding the water that a conventional aqueous sodium nitrite/acid diazotisation would introduce.
Dye & Pigment Intermediate Synthesis
Used in the synthesis of certain dye and pigment intermediates requiring a nitrosation or diazotisation step under non-aqueous conditions.
Specialty Fine-Chemical Nitrosation
Used in other fine-chemical nitrosation reactions across pharmaceutical and specialty-chemical manufacture where anhydrous conditions are specifically required.
How the reagent is typically used forward
The reagent's non-aqueous nitrosonium reactivity governs almost all of Nitrosylsulfuric Acid's further use. The categories below account for most of the ways it is applied in downstream synthesis.
Reduction to Hydroxylamine Sulfate
Catalytically reduced with hydrogen, typically over a platinum or similar catalyst, converting the nitrosylsulfuric acid intermediate into hydroxylamine, captured directly as its stable sulfate salt.
Diazotisation of Aromatic Amines
Reacted with an aromatic amine under anhydrous acidic conditions, the nitrosonium species converts the amine directly to its diazonium salt without introducing the water a conventional aqueous diazotisation method would bring.
Nitrosation of Other Nucleophiles
Reacted with other suitable nucleophilic substrates under anhydrous conditions to introduce a nitroso group where aqueous nitrosation methods would be unsuitable.
Controlled Hydrolysis (By-Product Management)
Where the reagent is used in excess or must be quenched, controlled hydrolysis converts it back to nitrous acid/nitrogen oxides and sulfuric acid, managed with appropriate gas scrubbing given the toxicity of the nitrogen oxides released.
Nitrosylsulfuric Acid against related nitrogen/sulfuric chemistry we supply
Buyers sourcing Nitrosylsulfuric Acid for hydroxylamine sulfate manufacture, or for diazotisation chemistry, often also need the related nitrogen-oxide source or downstream reagent. A quick reference to what else is on our regular supply list.
| Product | CAS Number | Category | Notes |
|---|---|---|---|
| Nitrosylsulfuric Acid | 7782-78-7 | Mixed nitrosating/sulfuric acid | The product on this page — a non-aqueous nitrosating and diazotising reagent. |
| Hydroxylamine Sulfate | 10039-54-0 | Inorganic amine reagent | The downstream product of the Raschig-Hooker process this reagent is a key intermediate toward — see its product page. |
| Nitric Acid | 7697-37-2 | Mineral acid / nitrogen oxide source | A related nitrogen-oxide source and mineral acid from our broader catalogue — see its product page. |
| Sulfuric Acid | 7664-93-9 | Mineral acid | The parent acid this reagent's chemistry is built on — see its product page. |
Exact physical constants and purity specifications are confirmed per batch on the certificate of analysis — treat the notes above as a sourcing guide, not a specification sheet, for products other than Nitrosylsulfuric Acid.
Safety classification at a glance
Based on GHS classification as commonly listed for this substance. This is a summary for orientation only — always work from the current safety data sheet supplied with your specific batch.
Causes severe skin burns and eye damage.
Toxic if inhaled.
Reacts violently with water.
Hydrolysis releases toxic nitrogen oxide gases alongside corrosive sulfuric acid.
Chemical-resistant gloves, full-face respiratory protection and acid-resistant clothing are required for routine handling.
Must be handled under strictly moisture-controlled conditions.
Danger
This product causes severe skin burns and eye damage on contact, is toxic if inhaled, and reacts violently with water, releasing a combination of corrosive sulfuric acid and toxic nitrogen oxide gases on hydrolysis. Handling requires chemical-resistant gloves, full-face respiratory protection, acid-resistant clothing and work in a fume hood or otherwise well-ventilated, moisture-controlled area with appropriate gas-scrubbing provision for any controlled quenching or hydrolysis step. Full first-aid, storage, spill and PPE guidance is in the MSDS issued with every shipment, and must be read in full before this material is handled.
Keeping it on spec between delivery and use
General storage guidance for this grade. Site-specific storage rules, segregation requirements and re-test intervals should follow your own EHS procedures and the MSDS issued with your batch.
Store in specialist lined, moisture-excluding containers in a cool, dry area, strictly away from water, organic materials and strong reducing agents (which can react with the nitrosonium species). Any container showing signs of pressure build-up or discoloured fuming (indicative of NOx release) should be treated with particular caution and isolated rather than opened under uncontrolled conditions. Re-check assay on a batch held past its retest date before use.
How it ships from Indonesia
Standard packing and export terms for this product. Confirm exact figures against your order — they vary slightly by destination and quantity.
What travels with every batch
Specification is agreed before the purchase order, not discovered on arrival. Every shipment of Nitrosylsulfuric Acid leaves with a documented, checkable paper trail.
Certificate of Analysis
Batch-wise assay, colour and key physical constants, issued against the agreed specification so your QC team can check it, not just file it.
Safety Data Sheet
GHS-format SDS in English covering hazard classification, handling, storage, first-aid and spill response for the exact grade shipped.
Technical Data Sheet
Reference physical and chemical properties, recommended storage and typical applications, for internal circulation to your process or R&D teams.
Certificate of Origin
Confirms Indonesian origin for customs clearance and any preferential-duty claim at your destination port.
Dangerous Goods Declaration
UN packing group, classification and shipper's declaration prepared ahead of loading so documentation never holds up customs.
Third-Party Inspection
Independent pre-shipment inspection and re-sampling can be arranged on request, at your cost, for buyers who require it as a matter of policy.
Frequently asked questions
What buyers most often ask our sales desk about this grade.
01What is Nitrosylsulfuric Acid used for?+
02Why use Nitrosylsulfuric Acid instead of the usual sodium nitrite/acid diazotisation method?+
03How is Nitrosylsulfuric Acid produced?+
04What grades does Chelora Chemicals supply?+
05Is Nitrosylsulfuric Acid hazardous?+
06What packing options are available?+
07How long does delivery take?+
08Can I get a sample before placing a bulk order?+
09Do you supply the downstream hydroxylamine sulfate and related nitrogen/sulfuric reagents as well?+
10What is the minimum order quantity?+
Need Nitrosylsulfuric Acid on spec, on time?
Send us your required form (solid/molten/solution), quantity, packing preference and destination port. Our desk quotes most enquiries within one working day.