Industrial grade, electronic grade 99% Dimethyl sulfoxide 67-68-5 DMSO

What is dimethyl sulfoxide (DMSO)? How does it work? What are its industrial applications ?

1. What is dimethyl sulfoxide? How does it work?

Dimethyl sulfoxide (DMSO, also known as methylsulfinylmethane or Dermasorb) is the oxidation product of dimethyl sulfide and is the most widely used sulfoxide compound in the commercial market. It is hailed as a "universal solvent" in the chemical industry. Its molecular formula is:

C2H6OS (molecular weight approximately 78.13; CAS No.: 67-68-5; EC No.: 200-664-3)

It is a colorless and transparent liquid at room temperature, almost odorless (it produces a garlic-like odor upon skin contact), with a melting point of 18.5-19℃ (it solidifies near room temperature; proper insulation is required for winter transportation and storage), a boiling point of 189℃, a density of 1.1004 g/cm³ (20℃), a refractive index of 1.479, a viscosity of 1.996 cP (20℃), a flash point of 89℃, a dielectric constant as high as 48, a dipole moment of 3.96 D, and a vapor pressure of 0.556 mbar (20℃). It is completely miscible with water and most organic solvents such as ethanol, acetone, chloroform, and benzene, but insoluble in ether, making it one of the most powerful industrial organic solvents.

Structurally, the DMSO molecule is trigonal pyramidal in shape, with the sulfur atom carrying a lone pair of electrons and forming a strong polar S=O bond with the oxygen atom. The oxygen end is highly electronegative, while the sulfur end is positively charged. The entire molecule has both strong polarity and electron-donating ability, which allows it to dissolve both polar and nonpolar compounds, as well as many inorganic salts and polymers. This is the structural basis for its reputation as a "universal solvent".

Chemically, DMSO is a typical strongly polar aprotic solvent, relatively stable but participating in a variety of reactions: the methyl group has a pKa of approximately 35 (weakly acidic), tolerates strong bases, and can be used in carbanion systems; both the sulfur and oxygen centers are nucleophilic, making it a mild oxidant (Swern, Corey-Kim, Pfitzner-Moffatt oxidation reactions) and a transition metal ligand; it is low in toxicity (oral LD50 in rats is approximately 14500 mg/kg, lower than ethanol's 7060 mg/kg) and non-flammable (flash point 89℃), but it is highly hygroscopic, easily penetrates skin, and can carry solutes through biological membranes; therefore, precautions must be taken for industrial use. Storage should be sealed, moisture-proof, protected from light, and kept away from oxidants and acyl chlorides.

In terms of grade definition, "industrial grade" as referred to in this article refers to DMSO specifications used in industrial production processes and formulation systems such as chemical, petrochemical, chemical fiber, gas purification, agrochemical, coating, cleaning, new energy, leather textile, and polymer, mainly for factory workshops and industrial production lines;

From the perspective of its mechanism of action, DMSO exerts its effects through its unique properties of "universal dissolution + reaction participation + selective extraction + hygroscopic swelling + penetration aid". The mechanisms of action in different industrial applications are as follows:

1.Universal dissolution mechanism (high dielectric constant and strong electron-donating property)

DMSO has a high dielectric constant (48), high polarity and strong electron donating ability at the oxygen end. It can dissolve salts and polar compounds by strong polar solvation, and it can dissolve non-polar compounds by its hydrophobic methyl end. It also can form hydrogen bonds/dipole interactions with polymers to swell and dissolve them. This versatility is the main reason for its “universal solvent” status and the main reason for its choice in industrial formulations.

2.Reaction participation mechanism (nucleophilic/oxidative/coordinative)

DMSO has a nucleophilic sulfur center and a nucleophilic oxygen center, which can act as a mild oxidant (Swern et al. oxidized alcohols to aldehydes and ketones), as a ligand to coordinate with transition metals, and can also provide a weakly acidic methyl group to generate a carbanion under strong base conditions, making it a multifunctional reaction medium in organic synthesis, polymerization reactions and coordination chemistry.

3.Extraction selection mechanism (selective dissolution)

DMSO possesses a high solubility selectivity for different substances (e.g., higher solubility selectivity for aromatics than for alkanes, and selective absorption of sulphides). It can realise industrial separation such as aromatic extraction, gas desulfurization etc. by using the principle of liquid-liquid extraction and absorption-desorption, which is the mechanistic basis of petrochemical and gas purification.

4.Moisture absorption and swelling mechanism (strong hygroscopicity and swelling capacity)

DMSO is highly hygroscopic and can form hydrogen bonds with polysaccharides like cellulose and various polymers, thus penetrating into fibres and paint films and causing swelling . It is used in industrial applications such as leather and textile penetration treatment, paint stripping and polymer processing.

5.Penetration aid mechanism (penetrating the substrate surface)

DMSO molecules are small and moderately polar, so they readily penetrate porous substrates, fibres, paint layers and dirt. This enables treatment and cleaning solutions to penetrate deeper into the target material, leading to an improvement in penetration, cleaning and stripping efficiency. It is an auxiliary mechanism for paint stripping, cleaning and leather and textile treatment.

In summary, DMSO is a versatile industrial strong polar aprotic solvent: it can dissolve almost all substances as a universal solvent, participate in oxidation and coordination reactions as a reaction medium, achieve aromatic hydrocarbon extraction and gas desulfurization as an extractant, and serve as a penetrating swelling agent for paint stripping, cleaning, leather textiles and polymer processing. It is one of the most widely used organic solvents in industry.

What are all the uses of industrial-grade dimethyl sulfoxide?

1.Solvents for organic synthesis reactions (core application in the chemical industry)

Application Field: Fine Chemicals

Corresponding Products: Finkelstein reaction solvent, nucleophilic substitution reaction solvent, dye / intermediate synthesis solvent, polymerization reaction solvent

Applicability Principle: DMSO is a strongly polar aprotic solvent. It strongly solvates cations while barely solvating anions, greatly boosting the activity of nucleophiles such as halide ions and accelerating SN2 substitution reactions including the Finkelstein reaction. Meanwhile, it dissolves various salts and organic compounds, features a high boiling point and low volatility, making it an irreplaceable reaction medium for industrial organic synthesis.

2.Aromatic hydrocarbon extraction solvent (petrochemical industry)Application Field: Petrochemical Industry

Corresponding Products: Aromatics recovery units for catalytic reforming naphtha, BTX recovery and separation processes, aromatics processing solvents

Applicability Principle: DMSO demonstrates far better selectivity for aromatics than non-aromatic hydrocarbons. Using liquid-liquid extraction principles, it selectively extracts aromatic compounds such as benzene, toluene and xylene from alkane mixtures in reformate oil. The solvent can be recovered through distillation for recycling, so it is one of the classic aromatic extraction solvents in the petrochemical sector.

3.Solvent for spinning acrylic fibres (chemical fibre industry)Application Field: Synthetic fibre industry

Corresponding Products: Polyacrylonitrile (acrylic fibre) spinning solution, acrylic fibre dry/wet spinning process, solvent for the preparation of carbon fibre precursor

Applicability Principle: DMSO is an excellent solvent for polyacrylonitrile. It dissolves the polymer to form a spinnable dope for acrylic fibre spinning. Its high boiling point, low volatility and good solubility guarantee stable and controllable spinning processes. Hence it represents one of the key solvent routes for manufacturing high-performance carbon fibre precursors.

4.Desulfurization of natural gas and refinery gas (gas purification area)

Application Field: Natural gas and petroleum refining industries

Corresponding Products: Natural gas desulfurization units, refinery gas mercaptan removal & desulfurization processes, tail gas purification absorption solventsApplicability Principle: DMSO has excellent selective solubility for sulphur-containing substances including hydrogen sulphide and mercaptans. It efficiently removes sulphides from natural gas and refinery gas via absorption-regeneration cycles to purify gas streams. The solvent can be regenerated and reused, functioning as a selective absorbent in gas desulfurization workflows.

5.Cosolvents for pesticide formulations (agrochemistry field)

Application Field: Pesticide formulation industry

Corresponding Products: Co-solvents for pesticide emulsifiable concentrates, adjuvants for water-in-oil/suspension formulations, solvents for seed coating agents and plant growth regulator formulations

Applicability Principle: Most pesticide technical materials have poor water solubility. DMSO dissolves many pesticide actives and improves miscibility within formulation systems. As a co-solvent, it disperses and emulsifies technical ingredients, enhancing formulation stability and spraying uniformity. It is a widely adopted co-solvent in pesticide formulations.

6.Environmentally friendly paint stripper components (coating and surface treatment field)

Application Field: Surface treatment and coating

Corresponding Products: Environmentally friendly paint remover, adhesive remover, industrial paint cleaner, paint removal agent for furniture refinishing

Applicability Principle: DMSO penetrates and swells polymers inside paint films, breaking the bonding force between coating layers and substrates. This causes aged paint and coatings to swell and peel rapidly. Compared with traditional paint removers containing benzene and dichloromethane, DMSO has low toxicity and is an important ingredient in green paint removers.

7.Cleaning field: industrial and precision cleaning

Application Field: Industrial cleaning

Corresponding Products: Precision parts cleaning agents, equipment maintenance cleaning agents, optical component cleaning agents, flux cleaning agents

Applicability Principle: DMSO possesses strong dissolving power and effectively removes contaminants such as grease, wax, resin and flux residues. It is non-flammable (flash point 89℃) and low in toxicity, suitable for cleaning precision components and sensitive substrates. It serves as an efficient, low-toxicity solvent for industrial precision cleaning.

8.Battery electrolyte solvents and additives (new energy field)

Application Field: New energy, energy storage

Corresponding Products: Co-solvents for lithium-ion battery electrolytes, electrolytes for supercapacitors, research solvents for electrochemical energy storage, formulation solvents for novel battery system development

Applicability Principle: DMSO has a high dielectric constant (48), which facilitates dissociation of lithium salts and other electrolytes and improves electrolyte ionic conductivity. Its wide electrochemical window and strong dissolving capacity for ionic liquids make it suitable as an electrolyte co-solvent or research solvent, delivering high value for new battery and electrochemical energy storage R&D.

9.Auxiliary agents for the treatment of leather and textiles (leather industry and textile industry)

Application Field: Leather and textile industry

Corresponding Products: Leather soaking and penetrating agents, fibre swelling treatment agents, textile dyeing and finishing auxiliaries, wool/cotton fibre pretreatment agents

Applicability Principle: DMSO penetrates into leather and cellulose fibre interiors and induces fibre swelling. This enables treatment liquids to deeply infiltrate fibre structures, improving leather softness as well as dyeing and finishing performance of textile fibres. It acts as a powerful swelling aid in leather and textile processing.

10.Polymerization of polymers and preparation of membrane material (Polymer Science)

Application Field: Polymer materials industry

Corresponding Products: Solvents for polymerisation reactions such as polysulfone and polyethersulfone, solvents for solution casting of separation membranes, solvents for the preparation of functional polymers and coating resins

Applicability Principle: DMSO can dissolve numerous monomers and polymers. Thanks to its high boiling point and low side-reaction rate, it works well as a polymerisation solvent for polycondensation reactions. Its high solubility makes it a common solvent for manufacturing separation membranes (phase inversion casting solutions) and preparing functional polymers.

To put it simply, dimethyl sulfoxide (CAS 67-68-5) is the most commonly used sulfoxide-based strongly polar aprotic solvent. It has multiple mature industrial applications: organic synthesis (reaction solvent), petrochemicals (aromatic extraction), chemical fibres (acrylic spinning), gas purification (natural gas desulfurization), coatings (environmentally friendly paint remover), cleaning (precision cleaning), new energy (battery electrolyte), leather and textiles (penetration swelling), polymers (polymerisation and membrane materials) and veterinary drug solvents. Its universal dissolving capability and low toxicity make it one of the most widely used organic solvents in industry.