Methyl sulfoxide

Product Details

CasNo： 67-68-5

MF： C2H6OS

Appearance： liquid

Delivery Time： 15 days

Packing： 200kg/drum

Purity： 99%

1. Basic Information

• Chinese Name: 二甲基亚砜
• English Name: Dimethyl sulfoxide (Abbreviation: DMSO)
• CAS No.: 67-68-5
• Molecular Formula: C2​H6​OS
• Relative Molecular Weight: 78.13
• Appearance: Colorless, odorless transparent liquid at room temperature (may develop a slight garlic-like odor if contaminated with impurities or oxidized).
• Melting Point: 18.4℃ (unique characteristic—solidifies into white crystals at temperatures below 18℃; can be melted by gentle heating [e.g., 25–30℃] without affecting purity).
• Boiling Point: 189℃ (high boiling point, suitable for high-temperature reactions as a solvent).
• Flash Point: 95℃ (closed cup; classified as a combustible liquid, lower fire risk compared to low-flash-point solvents).
• Relative Density: 1100 kg/m³ (1.100 g/cm³ at 20℃; slightly denser than water).
• Solubility: Miscible with most organic substances such as water, ethanol, propanol, benzene, and chloroform; can dissolve many inorganic salts (e.g., sodium chloride, potassium nitrate) and polymers (e.g., polyacrylonitrile), earning it the title of "universal solvent."

2. Chemical Properties

• Acidity and Alkalinity: Exhibits weak basicity; can react with protons to form salts (e.g., reacting with nitric acid to generate sulfoxide nitrate, (CH3​)2​SO⋅HNO3​).
• Redox Reactions:
  • Oxidation: Can be oxidized to dimethyl sulfone ((CH3​)2​SO2​) by oxidizing agents such as potassium permanganate (KMnO4​) or hydrogen peroxide (H2​O2​).
  • Reduction: Can be reduced to dimethyl sulfide ((CH3​)2​S) by reducing agents such as ferrous salts or hydrogen iodide (HI).
• Reactions with Organic Halides: Reacts with specific types of organic halides—for example, reacting with α-haloketones or α-haloesters to form α-ketoaldehydes or α-aldehydo esters.
• Hazardous Reactions:
  • Reacts explosively with concentrated perchloric acid (HClO4​) (especially at high concentrations or elevated temperatures).
  • Undergoes violent exothermic reactions with acyl halides (e.g., acetyl chloride) and their derivatives, potentially causing splashing or gas release.

3. Core Applications

3.1 Solvent (Primary Application)

• Used extensively as a solvent and reaction reagent:
  • In aromatic hydrocarbon extraction (separating aromatics from petroleum fractions) and acrylonitrile polymerization (as a solvent for polyacrylonitrile spinning, improving fiber uniformity).
  • As a polymerization and spinning solvent for polyacrylonitrile and cellulose acetate, enabling the production of high-performance synthetic fibers.
• In organic synthesis: Serves as a solvent for Grignard reactions, Friedel-Crafts reactions, and oxidation-reduction reactions, enhancing reaction rates and product yields.

3.2 Pharmaceutical Industry

• Permeation Protector: Reduces the freezing point of cells and minimizes ice crystal formation, widely used in cell cryopreservation (e.g., preserving stem cells, blood cells) and organ transplantation (short-term organ preservation).
• Transdermal Penetration Enhancer: One of the earliest used transdermal enhancers; it can disrupt the skin’s stratum corneum barrier, promoting the transdermal absorption of drugs (e.g., in anti-inflammatory ointments, pain-relief patches).
• Pharmacological Effects: Exhibits anti-inflammatory, analgesic, and anti-edema properties; used in topical formulations to relieve joint pain, muscle soreness, and skin inflammation.

3.3 Pesticide Industry

• Acts as a solvent, penetrant, and synergist for pesticides and agricultural fertilizers:
  • Improves the solubility of fat-soluble pesticide active ingredients, ensuring uniform dispersion in formulations.
  • Enhances pesticide penetration into plant cuticles or insect exoskeletons, boosting pest control efficiency; increases fertilizer absorption by crop roots or leaves.

3.4 Electronics Industry

• Used for cleaning electronic components and integrated circuits:
  • Removes organic contaminants (e.g., resin residues, oil stains), inorganic impurities (e.g., metal oxides), and polymer residues (e.g., photoresists) in one step, without corroding metal or semiconductor materials.
  • As a dielectric for capacitors, it has high insulation performance and stable electrical properties, suitable for high-temperature and high-humidity environments.

3.5 Other Fields

• Textile Industry: Serves as a dye solvent, stripping agent, and dyeing carrier for synthetic fibers (e.g., polyester, nylon), improving dyeing uniformity and color fastness.
• Gas Absorption: Used to absorb acetylene (C2​H2​) and sulfur dioxide (SO2​) from industrial waste gas, enabling gas purification and recycling.
• Other Uses: Functions as an antifreeze (prevents freezing of aqueous solutions in low-temperature equipment) and a plasticizer (enhancing the flexibility of PVC and polyurethane materials).

4. Safety Information

4.1 Toxicity

• Low Intrinsic Toxicity: DMSO itself has low acute toxicity (oral LD₅₀ for rats: ~14,500 mg/kg); however, it has strong skin penetration—it can carry other toxic substances (e.g., pesticides, heavy metals) through the skin into the bloodstream, amplifying the toxicity of co-existing compounds.
• Skin Effects: Contact with high-concentration (≥90%) or large-volume DMSO may cause skin redness, itching, dryness, or dermatitis; prolonged exposure can lead to skin peeling.
• Systemic Effects: High-dose exposure (e.g., inhaling large amounts of vapor or ingesting) may cause central nervous system disturbances (initial excitement, followed by drowsiness or confusion), hemolysis (red blood cell damage), and hemoglobinuria (hemoglobin in urine), potentially damaging the kidneys.

4.2 Fire and Explosion Hazards

• Combustible: Its vapor can form explosive mixtures with air (explosion limits: ~2.6%–28.5% volume fraction); contact with open flames, high heat, or electrostatic sparks may trigger combustion or explosion.
• Combustion Products: Release toxic gases such as sulfur dioxide (SO₂) and carbon monoxide (CO); avoid inhaling smoke during fire fighting.

4.3 Protective Measures

• Personal Protection:
  • Wear nitrile rubber gloves (latex gloves are permeable to DMSO) and chemical-resistant goggles (to prevent eye contact).
  • In high-concentration vapor environments, wear an organic vapor respirator (N95 or higher grade); avoid direct skin contact—immediately rinse with soap and water if contact occurs.
• Workplace Safety: Use explosion-proof electrical equipment and ground containers to eliminate static; prohibit smoking or eating in the work area.

5. Packaging and Storage

5.1 Packaging

• Industrial Grade (Bulk): Packaged in 200 L aluminum drums (aluminum is corrosion-resistant to DMSO) or 1000 L intermediate bulk containers (IBCs) with high-density polyethylene (HDPE) inner liners (suitable for large-scale transportation and storage).
• Reagent Grade (Small Volume): Available in 500 mL, 1 L, or 5 L amber glass bottles (to block light and slow oxidation) or HDPE plastic bottles (for low-cost, shatterproof storage); sealed with polytetrafluoroethylene (PTFE)-lined caps to prevent moisture absorption or vapor leakage.
• Pharmaceutical Grade: Packaged in sterile, pyrogen-free HDPE bottles or glass vials (10 mL–500 mL), compliant with pharmaceutical packaging standards (e.g., USP, EP) to ensure sterility and purity.

5.2 Storage

• Store in a cool, dry, well-ventilated warehouse with a temperature controlled at 15–30℃ (avoiding low temperatures that cause solidification or high temperatures that accelerate oxidation).
• Keep containers tightly sealed to prevent moisture absorption (DMSO is hygroscopic) and oxidation (oxidation produces dimethyl sulfone, reducing purity).
• Store separately from strong oxidants (e.g., KMnO₄), strong acids (e.g., HClO₄), acyl halides, and food chemicals to avoid hazardous reactions or cross-contamination.
• Label clearly with "Combustible Liquid" and "Skin Irritant" warning signs; avoid storing near heat sources (e.g., heaters, steam pipes).