Dimethyl Sulfoxide (DMSO)

   CAS No.: 67-68-5
   Synonyms / IUPAC Name: Dimethyl sulfoxide, methanesulfinylmethane
   Molecular Formula: C₂H₆OS
   Molecular Weight: 78.13 g/mol

Physicochemical Properties (Typical)

• Appearance: Colorless to pale yellow liquid
• Odor: Slightly sulfur-like or garlicish on skin contact
• Melting / Freezing Point: ~18–20 °C
• Boiling Point: ~189 °C
• Density (20 °C): ~1.10 g/cm³
• Refractive Index (n²⁰ᴰ): ~1.479
• Solubility: Fully miscible with water and most organic solvents
• Viscosity: ~2.2 cP at 20 °C
• Vapor Pressure (20 °C): ~0.6 Torr (~0.8 mmHg)
• Dielectric Constant: ~46.7 (20 °C)
• Stability: Stable under normal handling; hygroscopic and can absorb water

Purity & Quality Standards

• Purity (by GC or equivalent): ≥ 99.0%
• Water / Moisture Content: Typically ≤ 0.2%
• Non-volatile Residue: Minimal (<0.01%)
• Heavy Metals and Impurities: Strictly limited
• Analytical Methods: Gas chromatography, Karl Fischer titration, spectroscopy
• Documentation: Certificate of Analysis (COA) and Safety Data Sheet (SDS) provided

Applications / Uses

• High-performance polar aprotic solvent for synthesis, extraction, and formulation
• Used in pharmaceuticals, fine chemicals, agrochemicals, polymers, and electronics
• Serves as a cryoprotectant in biological and medical applications
• Applied as reagent or medium in advanced chemical reactions

Safety & Handling

• Hazard Classification: Flammable liquid (Class 3) under certain conditions
• Health Effects:
• Skin contact may cause absorption and transport of dissolved substances
• Eye contact may cause irritation
• Inhalation of vapor or mist may cause discomfort
• Precautions:
• Ensure good ventilation
• Wear solvent-resistant gloves, eye protection, and protective clothing
• Avoid ingestion and prolonged skin contact
• Fire & Explosion: Vapors can ignite; keep away from sparks, open flame, or heat
• Reactivity / Incompatibilities: Avoid contact with strong oxidizers, halogens, or reactive metals
• First Aid Measures:
• Inhalation – Move to fresh air
• Skin – Wash thoroughly with soap and water
• Eyes – Flush with clean water for several minutes
• Ingestion – Seek medical advice immediately

Packaging & Storage

• Packaging: Sealed solvent-resistant containers (metal drums, lined vessels)
• Storage Conditions: Store in cool, dry, and ventilated area away from ignition sources
• Container Closure: Keep tightly closed to avoid moisture absorption and contamination
• Storage Temperature: Recommended below 30 °C
• Shelf Life: 12–24 months under proper storage conditions