1. Basic chemical properties

Chinese name: Dimethyl sulfoxide

English name: Dimethyl Sulfoxide (DMSO)

CAS number: 67-68-5

Molecular formula: C₂H₆OS

Molecular weight: 78.13

Physical properties:

Appearance: Colorless transparent liquid, slightly garlicky

Density: 1.1004 g/cm³ (25℃)

Melting point: 18.4℃

Boiling point: 189℃

Flash point: 95℃ (closed cup)

Solubility: Miscible with water, ethanol, acetone, strong polar aprotic solvent

2. Main application areas

(1) Medicine and biotechnology

Drug carrier: As a transdermal absorbent, it enhances the permeability of drugs (such as anti-inflammatory drugs and analgesics).

Cell cryoprotection: Used for low-temperature preservation of biological samples (cells, tissues) (concentration 5%-10%).

Clinical trials: Treatment of diseases such as interstitial cystitis and arthritis (requires high-purity pharmaceutical grade DMSO).

(2) Chemical industry and materials

Reaction solvent: Used in coupling reactions and polymerization reactions (such as polyimide synthesis) in organic synthesis.

Polymer materials: As a solvent for polyacrylonitrile and polyurethane, it is used in fiber spinning and film production.

Electronic industry: Cleaning semiconductor wafers and removing photoresist residues (requires electronic grade DMSO).

(3) Agriculture and environmental protection

Pesticide synergist: Improve the leaf penetration efficiency of herbicides (such as glyphosate).

Soil remediation: Extract organic pollutants such as polycyclic aromatic hydrocarbons (PAHs).

3. Production process and quality standards

Synthesis method:

Methanol reacts with hydrogen sulfide to produce dimethyl sulfide (CH₃SCH₃);

Oxidation of dimethyl sulfide (catalyzed by nitric acid or oxygen) to produce DMSO.

Purity level:

Industrial grade: ≥99.5%, used for chemical synthesis;

Pharmaceutical grade: ≥99.9% (USP/EP standard), must pass bacterial endotoxin test;

Electronic grade: metal ion content ≤1ppb, particle size ≤0.1μm.

Detection method: gas chromatography (GC), high performance liquid chromatography (HPLC), ICP-MS (metal impurity analysis).

4. Safety and storage regulations

Health risks:

Skin contact: Rapid penetration and carrying other substances into the blood, which may cause allergies;

Inhalation: Irritating the respiratory tract, high concentrations cause headaches and nausea.

Protective measures:

Wear nitrile gloves, goggles and gas masks during operation;

Avoid contact with strong oxidants (such as hydrogen peroxide) to prevent violent reactions.

Storage conditions:

Sealed and light-proof, temperature 15-25℃;

Keep away from fire sources, and the storage area must be well ventilated.

5. Industry trends and innovative applications

Green synthesis: Develop bio-based DMSO (using lignin as raw material) to reduce carbon emissions;

Medical research and development: As a cryoprotectant for CAR-T cell therapy, it replaces traditional DMSO to reduce toxicity;

New energy: Used in lithium-sulfur battery electrolytes to improve battery cycle stability.

Procurement recommendations

Clearly define the purpose: select the corresponding purity grade (industrial/pharmaceutical/electronic grade);

Verify qualifications: request COA (quality certificate), MSDS and third-party test report (such as heavy metal content);

Small sample test: For pharmaceutical/electronic applications, it is recommended to try a small batch first.

Chemical properties

Dimethyl sulfoxide is a strong non-proton polar compound, so it has no acidity or alkalinity. It is a colorless liquid at room temperature and is hygroscopic. It is almost odorless and has a bitter taste. It is soluble in water, ethanol, acetone, ether, benzene and chloroform. This product is weakly alkaline, unstable to acid, and generates salts when it encounters strong acid. It decomposes at high temperatures and reacts violently with chlorine. It burns in the air and emits a light blue flame. The oral LD50 of mice is 1700mg/kg.

Uses

1. Used as analytical reagent and gas chromatography stationary liquid, also used as solvent for ultraviolet spectrum analysis, also used for aromatic hydrocarbon extraction, reaction medium for resin and dye, acrylic fiber polymerization, solvent for spinning, etc.

2. Can be used as organic solvent, reaction medium and organic synthesis intermediate. It has a wide range of uses. This product has a high selective extraction ability and is used as polymerization and condensation solvent for acrylic resin and polysulfone resin, polymerization spinning solvent for polyacrylonitrile and acetate fiber, extraction solvent for separation of alkanes and aromatic hydrocarbons, and reaction medium for aromatic hydrocarbon, butadiene extraction, acrylic fiber spinning, plastic solvent and organic synthetic dye, pharmaceutical and other industries. In medicine, dimethyl sulfoxide has anti-inflammatory and analgesic effects and has strong penetration into the skin, so it can dissolve certain drugs and allow such drugs to penetrate into the human body to achieve therapeutic purposes. Using this carrier property of dimethyl sulfoxide, it can also be used as an additive for pesticides. Adding a small amount of dimethyl sulfoxide to certain pesticides helps the pesticides penetrate into plants to improve their efficacy. Dimethyl sulfoxide can also be used as a dyeing solvent, dye remover, and dyeing carrier for synthetic fibers. It can also be used as an absorbent for recovering acetylene and sulfur dioxide, a synthetic fiber modifier, an antifreeze agent, a capacitor medium, a brake oil, and a rare metal extractant.

Production method

Dimethyl sulfoxide is generally produced by the dimethyl sulfide oxidation method. Due to the different oxidants and oxidation methods used, there are different production processes.

1. Methanol carbon disulfide method Methanol and carbon disulfide are used as raw materials, γ-Al2O3 is used as a catalyst, dimethyl sulfide is first synthesized, and then oxidized with nitrogen dioxide (or nitric acid) to obtain dimethyl sulfoxide.

2. Hydrogen peroxide method Acetone is used as a buffer medium to react dimethyl sulfide with hydrogen peroxide. The cost of producing dimethyl sulfoxide by this method is relatively high and is not suitable for large-scale production.

3. Nitrogen dioxide method Methanol and hydrogen sulfide are used to generate dimethyl sulfide under the action of γ-alumina; sulfuric acid reacts with sodium nitrite to generate nitrogen dioxide; dimethyl sulfide is then oxidized with nitrogen dioxide at 60-80°C in a gas-liquid phase to generate crude dimethyl sulfoxide. There is also direct oxidation with oxygen to generate crude dimethyl sulfoxide, which is then refined by vacuum distillation to obtain the finished dimethyl sulfoxide. This method is a more advanced production method.

4. Dimethyl sulfate method: Dimethyl sulfate is reacted with sodium sulfide to produce dimethyl sulfide; sulfuric acid is reacted with sodium nitrite to produce nitrogen dioxide; dimethyl sulfide is oxidized with nitrogen dioxide to obtain crude dimethyl sulfoxide, which is then neutralized and distilled to obtain refined dimethyl sulfoxide. In addition, dimethyl sulfoxide is produced from dimethyl sulfide by anodic oxidation.

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