Physical Properties
- Molecular Formula: C₂H₆OS
- Molecular Weight: 78.13 g/mol
- Appearance: Colorless, hygroscopic liquid (may appear slightly yellow if impure)
- Odor: Odorless (pure), but metabolized compounds can produce a garlic-like taste/smell
- Boiling Point: ~189°C (372.2°F)
- Melting Point: ~18.5°C (65.3°F)
- Density: 1.1004 g/cm³ at 20°C
- Refractive Index: 1.479 (20°C)
- Viscosity: 1.996 cP at 20°C
- Surface Tension: 43.54 mN/m at 20°C
- Dielectric Constant: ~47 (highly polar)
- Flash Point: 95°C (203°F) (closed cup)
- Autoignition Temperature: 215°C (419°F)
- Vapor Pressure: 0.42 mmHg at 20°C
- Heat of Vaporization: 52.9 kJ/mol
- Miscibility:
- Fully miscible with water, alcohols, acetone, ether, benzene, chloroform
- Immiscible with paraffins (e.g., hexane, mineral oil)
- Solvent Properties:
- Excellent polar aprotic solvent
- Dissolves polar & nonpolar compounds (e.g., salts, polymers, drugs)
- Penetrates biological membranes easily
Chemical Properties
- Structure: Sulfoxide functional group (S=O) with two methyl groups
- Reactivity:
- Nucleophilic at oxygen, electrophilic at sulfur
- Can act as a ligand in coordination chemistry
- Redox Reactions:
- Can be reduced to dimethyl sulfide (DMS, (CH₃)₂S)
- Oxidized to dimethyl sulfone (DMSO₂, (CH₃)₂SO₂)
- Hydrogen Bonding: Strong H-bond acceptor (but poor donor)
- Stability:
- Stable under normal conditions
- Decomposes at high temps (>189°C) → releases SO₂, CH₄, COS
- Reacts violently with strong oxidizers (e.g., H₂O₂, HNO₃, perchlorates)
- Forms explosive mixtures with metal perchlorates
Biological & Pharmacological Properties
- Cell Permeability:
- Rapidly penetrates skin, membranes, blood-brain barrier
- Used as a transdermal drug delivery enhancer
- Anti-inflammatory & Analgesic Effects:
- Used in pain relief (e.g., arthritis, sports injuries)
- May reduce swelling & oxidative stress
- Cryoprotectant: Preserves cells, tissues, organs in freezing (e.g., stem cells, embryos)
- Radical Scavenger: Reacts with hydroxyl radicals (•OH) → forms dimethyl sulfone
