Sulfur trioxide
Sulfur trioxide (CAS 7446-11-9, SO3), also known as sulfuric anhydride, is a powerful dehydrating and oxidizing agent. This highly reactive compound is critical in industrial chemical synthesis, particularly for the production of sulfuric acid, the most widely used chemical worldwide. Its strong affinity for water makes it a potent sulfonating agent in various organic chemistry applications. Sulfur trioxide is supplied by TSS with an assay of ≥99%.
- IUPAC
- Sulfuric anhydride
Sulfuric Acid Production
Sulfur trioxide is the direct precursor to sulfuric acid via the contact process, reacting with water. Sulfuric acid is a fundamental industrial chemical used in fertilisers, detergents, and numerous other applications.
Sulfonation Reactions
As a potent sulfonating agent, sulfur trioxide is essential for introducing sulfur trioxide groups into organic molecules. This is vital in the synthesis of detergents, dyes, and pharmaceuticals.
Dehydrating Agent
Its extreme affinity for water makes sulfur trioxide an effective dehydrating agent in specific chemical processes where water removal is critical.
Oleum Production
Sulfur trioxide is used to produce oleum (fuming sulfuric acid) by dissolving it in concentrated sulfuric acid. Oleum is a key reagent in organic synthesis and the petroleum industry.
| Molecular weight | 80.06 |
|---|---|
| Linear formula | SO3 |
| Assay | ≥99% |
| Boiling point | 44.7 °C(lit.) |
| Density | 1.97 g/mL at 25 °C(lit.) |
| Vapour pressure | 280 mmHg (25 °C) |
| Vapour density | 2.8 (vs air) |
| Melting point | 16.8 °C(lit.) |
| Contains / stabiliser | stabilizer |
Hazard statements
- H314Causes severe skin burns and eye damage
- H335May cause respiratory irritation
Precautionary statements
- P261Avoid breathing dust, fume, gas or vapours
- P280Wear protective gloves, clothing and eye/face protection
- P305IF IN EYES
- P310Immediately call a POISON CENTER or doctor
| Protective equipment | Faceshields, full-face respirator (US), Gloves, Goggles, multi-purpose combination respirator cartridge (US) |
|---|---|
| Transport (UN / ADR) | UN 1829 8/PG 1 |
| Water hazard class (WGK, DE) | 1 |
| Hazard codes (EU) | C |
| Risk statements (R) | 14-35-37 |
| Safety statements (S) | 26-30-36/37/39-45 |
| Supplemental hazards | Reacts violently with water. |
Hazard information is provided for guidance. Always consult the product Safety Data Sheet (SDS), available on request, before handling.
Documentation
Every batch ships with a Certificate of Analysis covering assay, identity and purity; the grade is confirmed against your enquiry. Safety Data Sheets and technical data sheets are available on request.
Supply & logistics
Samples for technical evaluation; bulk MOQ by grade and packaging. In-stock material ships in 7–10 working days, worldwide, with full export documentation.
What is Sulfur trioxide (CAS 7446-11-9) used for?
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Sulfur trioxide is primarily used as a precursor to sulfuric acid and oleum, and as a potent sulfonating and dehydrating agent in chemical synthesis, including the production of detergents, dyes, and pharmaceuticals.
What is the CAS number and chemical formula for Sulfur trioxide?
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The CAS number is 7446-11-9, and the chemical formula is SO3.
What grade and purity does Tech Serve Solutions supply for Sulfur trioxide?
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Tech Serve Solutions supplies Sulfur trioxide with an assay of ≥99%. We do not represent this product as USP, BP, EP, or any other pharmacopoeia grade unless explicitly stated in the product specifications.
How should Sulfur trioxide be handled safely?
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Sulfur trioxide is highly corrosive and reacts violently with water, releasing heat and toxic fumes. Handle with extreme caution, using appropriate personal protective equipment including faceshields, respirators, gloves, and goggles. Work in a well-ventilated area and avoid contact with water.
How is Sulfur trioxide packed, shipped, and exported?
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Sulfur trioxide is shipped as UN 1829, Hazard Class 8, Packing Group I. TSS adheres to all international regulations for the safe packaging, handling, and export of hazardous chemicals.
How can I request a sample or quote for Sulfur trioxide?
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Please contact our sales team via the website or phone to request a sample or a quotation for Sulfur trioxide.
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