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

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

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), 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 diethyl ether, making it one of the most potent organic solvents. Industrially, it is produced by oxidation of dimethyl sulfide, a byproduct of the Kraft process in papermaking, with oxygen or nitrogen dioxide. It was first synthesized by the Russian chemist Zaitsev in 1866.

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 for carbanion research; 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 (the oral LD50 in rats is approximately 14,500 mg/kg, lower than ethanol's 7,060 mg/kg), but it is highly hygroscopic, easily penetrates the skin, and can carry solutes through biological membranes. It should be stored in a sealed, moisture-proof, and light-protected environment, away from oxidants and acyl chlorides.

In terms of grading system, DMSO is classified into industrial grade, electronic grade, reagent grade (analytical grade/chromatographic grade/NMR grade), and cosmetic grade according to its use: industrial grade is used in industrial production such as chemical, petrochemical, chemical fiber, gas purification, and agrochemical industries; electronic grade is used in semiconductor and flat panel display manufacturing; and reagent grade is used in scientific research experiments.

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

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

DMSO has high dielectric constant (48), high polarity and high electron donating ability at the oxygen end. It is also a good solvent for salts and polar compounds due to strong polar solvation, and for nonpolar compounds due to the hydrophobic methyl end. It can also hydrogen bond/dipole interact with polymers causing their swelling and dissolution. This versatility is the basic reason for its being called a “universal solvent.”

2.Cryoprotection mechanism (inhibition of ice crystal formation and vitrification)

DMSO can enter the cell and hydrogen bond with water molecules, thus decreasing the freezing point of the solution and inhibiting the nucleation and growth of ice crystals. This allows the water to be in a glassy state rather than an ice crystal state during the cooling process, preventing ice crystals from piercing the cell membrane and protecting the cell’s activity during cryopreservation and thawing. It is the fundamental principle of cryopreservation technology.

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

DMSO has a nucleophilic sulphur and an oxygen that is nucleophilic. It can be used as a mild oxidant (Swern et al. oxidised alcohols to aldehydes and ketones), as a ligand for coordination with transition metals, and can also give a weakly acidic methyl group to give a carbanion with strong base conditions, and thus it is a multifunctional reaction medium in organic chemical synthesis and coordination chemistry.

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

DMSO is a very strong water attractor and can form hydrogen bonds with polysaccharides such as cellulose. This allows the DMSO to penetrate the fibre and cause it to swell. This property is used in the processing of cellulose, textile treatment and similar of the material.

II. What are all the uses of Dimethyl sulfoxide?

DMSO has applications spanning industry, electronics, scientific research, and veterinary medicine, making it one of the most widely used organic solvents. Each application is detailed below, including application field, corresponding products and applicability principle:

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, pesticide/dye / intermediate synthesis solvent, polymerization reaction solventApplicability Principle: DMSO is a strongly polar aprotic solvent. It strongly solvates cations while hardly solvating anions, significantly increasing the activity of nucleophiles such as halide ions and greatly accelerating SN2 substitution reactions (such as the Finkelstein reaction). Simultaneously, it can dissolve a variety of salts and organic compounds, has a high boiling point and low volatility, making it an irreplaceable reaction medium in industrial organic synthesis.

2.Aromatic hydrocarbon extraction solvent (petrochemical industry)

Application Field: Petrochemical industry

Corresponding Products: Oil aromatics extraction units for catalytic reforming, benzene/toluene/xylene (BTX) extraction and separation process

Applicability Principle: DMSO has much higher selectivity for aromatics than non-aromatic hydrocarbons. Based on the principle of liquid-liquid extraction, it can selectively extract aromatics such as benzene, toluene and xylene from alkane mixtures in reforming oil, and has become one of the classic solvents for aromatics extraction in the petrochemical industry.

3.Solvent for acrylic fibre spinning (Chemical fibre industry)

Application Field: Synthetic fibres industry

Corresponding Products: Polyacrylonitrile (acrylic fibre) spinning solution, dry/wet spinning processes of acrylic fibres

Applicability Principle: DMSO is a good solvent for polyacrylonitrile, dissolving the polymer to prepare a spinnable spinning solution. Acrylic fibres are obtained after spinning and solidification. As one of the classic solvents for acrylic fibre production, it features a high boiling point, low volatility and good solubility, which ensure stable and controllable spinning processes.

4.Natural gas and refinery gas desulphurization (gas purification field)

Application Field: Natural gas and oil refining industries

Corresponding Products: Natural gas desulfurization units, refinery gas mercaptan removal desulfurization processes, tail gas purification solvents

Applicability Principle: DMSO exhibits excellent selective solvency for sulphur compounds such as hydrogen sulphide and mercaptans. It can selectively remove sulphides from natural gas and refinery gas through absorption-regeneration cycles to purify gas streams. Meanwhile, the solvent can be regenerated and reused, so it serves as a selective absorbent in gas desulfurization workflows.

5.Components of environmentally friendly paint removers (coatings and cleaning industry)

Application Field: Surface coatings and surface treatment

Corresponding Products: Environmentally friendly paint remover, adhesive remover, industrial paint cleaner

Applicability Principle: DMSO can penetrate and swell the polymer in paint films, break the bonding force between the paint layer and the substrate, causing aged paint and coatings to swell and peel off rapidly. DMSO is less toxic and more environmentally friendly than traditional paint strippers containing benzene and dichloromethane, and is an important ingredient of green paint strippers.

6.Industrial and precision cleaning (cleaning area)

Application Field: Industrial cleaning

Corresponding Products: Precision parts detergents, equipment maintenance detergents, optical component detergents

Applicability Principle: DMSO is a powerful solvent that removes contaminants including grease, wax, resin, flux and more. It is non-flammable (flash point 89℃) and low in toxicity, suitable for cleaning precision parts and sensitive substrates. It is a highly efficient and low-toxicity solvent for industrial precision cleaning.

7.Solvents and additives of battery electrolyte (new energy field)

Application Field: New Energy, Energy Storage

Corresponding Products: Co-solvents for lithium-ion battery electrolytes, electrolytes for supercapacitors, solvents for electrochemical research

Applicability Principle: DMSO has a high dielectric constant of 48, which efficiently dissociates lithium salts and other electrolytes and improves the ionic conductivity of the electrolyte. Its wide electrochemical window and strong dissolving power make it a good candidate as an electrolyte co-solvent or research solvent, and thus valuable for the development of new batteries and electrochemical power storage technologies.

8.Leather and textile auxiliaries (leather and textile industry)

Application Field: Leather and textile industry

Corresponding Products: Leather soaking and penetrating agents, fibre swelling treatment agents, textile dyeing and finishing auxiliariesApplicability Principle: DMSO can penetrate into the interior of leather and cellulose fibres and induce fibre swelling, which helps treatment solutions deeply infiltrate fibre structures, improving leather softness as well as the dyeing and finishing performance of textile fibres. It functions as a swelling and penetrating agent applied in the leather and textile industries.

9.Polymer polymerization and membrane material preparation (Polymer Science)

Application Field: Polymer materials industry

Corresponding Products: Polymerization reaction solvents such as polysulfone and polyethersulfone, casting solution solvents for separation membranes, solvents for the preparation of functional polymers

Applicability Principle: DMSO can dissolve a variety of monomers and polymers. It has a high boiling point and minimal side reactions, making it suitable as a solvent for polymerization reactions such as polycondensation. Its strong solubility also makes it a commonly used solvent for preparing separation membranes (phase inversion casting solutions) and functional polymers.

10.Photoresist stripping solution (main application in semiconductor and flat panel display industries)

Application Field: Semiconductor and Display Manufacturing

Corresponding Products: TFT-LCD panel photoresist stripping solution, wafer photoresist removal solution, advanced packaging photoresist stripping process

Applicability Principle: Patterned photoresist must be fully removed after photolithography. DMSO effectively dissolves and swells photoresist resin without damaging the underlying metal, oxide layer and substrate. It is also safe and recyclable, which makes it the standard solvent for photoresist stripping in TFT-LCD panels and advanced packaging (wafer-level packaging, solder ball patterning).

11.Solvents for semiconductor wet processing (electronics area)

Application Field: Manufacture of integrated circuits

Corresponding Products: Wafer wet cleaning solution, photoresist/film stripping process solvent, electronic-grade cleaning reagents

Applicability Principle: Electronic-grade high-purity DMSO (ppb-level metal ions, excellent UV transmittance) can be used for wafer cleaning and removal of organic residues. It has excellent dissolving power for removing photoresist, flux and organic contaminants. Its high purity prevents metal contamination, making it a clean solvent for semiconductor wet processes.

12.Microelectronics manufacturing auxiliary processes (Electronics)

Application Field: Microelectronics fabrication

Corresponding Products: Solvent for manufacturing of TFT-LCD, solvent for manufacturing of MEMS devices, cleaning solution for electronic packaging

Applicability Principle: DMSO-based chemical formulations are used in microelectronics manufacturing for processes such as photoresist stripping and patterning cleaning. They feature good solubility selectivity and little damage to device structures, and are environmentally friendly, serving as multifunctional solvent systems in the electronic manufacturing process chain.

13.Universal solvent for laboratory use (primary application in scientific research)

Application Field: Chemical and biochemical research

Corresponding Products: Sample dissolving solvent, reaction solvent, stock solution preparation solvent, compound library storage solvent

Applicability Principle: DMSO can dissolve polar and nonpolar compounds, is miscible with water and culture media, and has a high boiling point and low volatility. Therefore, it is the preferred solvent for dissolving test compounds, preparing and storing stock solutions (compound libraries) for long-term preservation. It is also the most commonly used "universal solvent" in laboratories.

14.Solvents for NMR spectroscopy (analytical area)

Application Field: Analytical Chemistry

Corresponding Products: Deuterated dimethyl sulfoxide (DMSO-d6), NMR sample preparation solvent

Applicability Principle: DMSO-d6 dissolves a wide range of analytes, has a simple spectrum and is heat resistant, making it suitable for high-temperature NMR experiments. It is one of the most common deuterated solvents used in NMR spectroscopy (often mixed with CDCl3 to reduce viscosity and melting point).

15.PCR reaction additives (molecular biology)

Application Field: Molecular biology

Corresponding Products: PCR reaction system additives, reagents for amplification of high GC templates, sequencing reaction helpers

Applicability Principle: DMSO breaks inter-strand hydrogen bonds in DNA, disrupts the secondary structure of templates and primers (hairpin structure), lowers primer annealing temperature, and facilitates unwinding of high-GC content templates and supercoiled plasmids, thereby greatly improving the efficiency and specificity of PCR amplification. It is a classic molecular biology additive used in experiments.

16.Cryoprotectants for cell cryopreservation (cell biology)

Application Field: Cell biology and biobanks

Corresponding Products: Cell cryopreservation solution, stem cell cryopreservation systems, bacterial/cell line preservation solutions

Applicability Principle: DMSO can enter cells, lower the freezing temperature and inhibit ice crystal formation (approximately 10% DMSO for slow freezing at -80°C or liquid nitrogen preservation). Ice crystals will not damage cell membranes, and cells retain viability after thawing. It is the most widely used cryoprotectant for preserving cell lines, stem cells and bacterial strains.

17.Biochemical extractants (biochemical field)

Application Field: Biochemistry and cell biology

Corresponding Products: Extractants for lipophilic components, solvents for extracting cell contents, solvents for pretreatment of biological samples

Applicability Principle: DMSO can dissolve a variety of lipophilic and hydrophilic biomolecules. As an extractant, it can extract lipophilic components from biological samples and dissolve poorly soluble biomolecules, making it a commonly used extraction/solubilizing solvent in biochemical and cell experiments.

18.Non-aqueous pKa determination and carbanion research (physical organic chemistry field)

Application Field: Physical organic chemistry and chemical education research

Corresponding Products: Bordwell pKa meter solvent, carbanion reaction research medium, strong base system reaction solvent

Applicability Principle: The methyl group of DMSO is only weakly acidic (pKa≈35). It tolerates strong bases without being consumed and can stabilize carbanions. Therefore, it is widely adopted as a standard solvent for pKa determination of thousands of organic compounds in non-aqueous systems and for the study of carbanions (such as dimsyl anions).

19.Solvents for cosmetics and topical care products (daily chemical industry)

Application Field: Daily chemical and personal care industries

Corresponding Products: Solvents/penetration enhancers for topical care products, and some localized care formulations

Applicability Principle: DMSO's penetrating properties help active ingredients penetrate the stratum corneum of the skin, making it suitable as a solvent/penetration enhancer in some topical care formulations. However, since it can also carry other substances for transdermal absorption, its purity and dosage must be strictly controlled for daily chemical applications, limiting it to niche use cases.

In summary, dimethyl sulfoxide (CAS 67-68-5) is the most widely used sulfoxide-based strongly polar aprotic solvent. Leveraging five key mechanisms—universal dissolution, permeation, cryoprotection, reaction participation, and hygroscopic swelling—it has developed a comprehensive product system covering over thirty mature applications across four major sectors: industry (organic synthesis, aromatic hydrocarbon extraction, acrylic fiber spinning, gas desulfurization, pesticides, paint removers, cleaning, battery electrolytes, leather textiles, polymers), electronics (photoresist stripping, semiconductor wet processes), scientific research (universal solvent, NMR, PCR, biochemical extraction, pKa research), and veterinary medicine (equine liniments, transdermal carriers). Its universal solvent properties and low toxicity make it one of the most widely used organic solvents in the chemical and life sciences fields.