What Is Pure DMSO?
Pure dimethyl sulfoxide (DMSO) is an organosulfur compound with the molecular formula (CH3)2S=O and a molecular weight of 78.13. Its Chemical Abstracts Service number is 67-68-5. DMSO is a colorless liquid and is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and non-polar compounds, and it is miscible with a wide range of organic solvents as well as with water. These characteristics make DMSO one of the most versatile solvents available for scientific and industrial work.
Key Physical and Chemical Properties
The main properties of pure DMSO are summarized below.
| Property | Value |
|---|---|
| Chemical name | Dimethyl sulfoxide |
| CAS number | 67-68-5 |
| Molecular formula | (CH3)2S=O |
| Molecular weight | 78.13 |
| Appearance | Colorless liquid |
| Boiling point | Approximately 189 C |
| Melting point | Approximately 19 C |
| Solvency | Dissolves polar and non-polar compounds; miscible with water and most organic solvents |
| Hygroscopicity | Hygroscopic; absorbs moisture from the air |
Pure DMSO has a high dielectric constant and strong electron-donating ability, which explains its exceptional dissolving power and its frequent use as a reaction medium in organic synthesis.
Medical and Clinical Use of Pure DMSO
Dimethyl sulfoxide is a purified preparation used in medicine to relieve the symptoms of interstitial cystitis, a chronic bladder condition. The procedure is carried out by a healthcare professional:
A catheter or syringe is used to place the DMSO solution into the bladder.
The solution is allowed to remain in the bladder for about 15 minutes.
The patient then expels the solution by urinating.
In addition, DMSO is used in topical pharmaceutical preparations as a penetration enhancer, helping active ingredients reach deeper layers of the skin. Its medical applications are subject to regulatory approval and must always be performed under professional supervision.
Laboratory and Industrial Applications
Beyond clinical use, pure DMSO is widely employed in laboratories and industry:
Reaction solvent: its polar aprotic nature accelerates many organic reactions, including nucleophilic substitutions.
Extraction and purification: DMSO is used to separate and purify organic compounds, polymers and certain inorganic materials.
Electronics cleaning: its strong solvency and high boiling point make it useful for precision cleaning of semiconductors and optical components.
Biochemistry: DMSO is used as a cryoprotectant in cell freezing and as a solvent for water-insoluble compounds in assays.
Analytical chemistry: it is a common solvent for nuclear magnetic resonance spectroscopy and other analytical techniques.
Polymer processing: DMSO supports the production of acrylic fibers and other specialty polymers.
This wide range of applications reflects the unique solvency profile of pure DMSO.
Quality and Handling Considerations
When selecting and handling pure DMSO, the following points are important:
Purity grade: high-purity grades such as 99.9% are preferred for pharmaceutical, analytical and electronics applications; verify the water content, which should be low because DMSO is hygroscopic.
Storage: keep containers tightly sealed in a cool, dry place to prevent moisture absorption.
Skin penetration: DMSO readily penetrates the skin and can carry dissolved substances into the body; wear chemically resistant gloves and protective clothing.
Compatibility: avoid mixing DMSO with strong oxidizing or reducing agents without a compatibility review.
Medical use: any therapeutic use of DMSO must follow approved protocols and professional medical guidance.
With correct grade selection and handling, pure DMSO is a safe and valuable solvent across many fields.
Frequently Asked Questions
What is pure DMSO used for?
Pure DMSO is used as a versatile solvent in laboratories and industry, as a penetration enhancer in topical pharmaceutical preparations, and as a bladder instillation for interstitial cystitis symptom relief under medical supervision.
Is pure DMSO safe?
Pure DMSO has relatively low acute toxicity, but it penetrates the skin rapidly and can carry dissolved substances into the body. It can also irritate skin and eyes. Handle it with chemically resistant gloves and follow professional guidance for any medical use.
What is the formula of DMSO?
The molecular formula of dimethyl sulfoxide is (CH3)2S=O, with a molecular weight of 78.13.
Why is DMSO called a universal solvent?
DMSO dissolves both polar and non-polar compounds and is miscible with water and most organic solvents, which gives it one of the broadest solvency ranges of any common solvent.
How is DMSO used for interstitial cystitis?
A healthcare professional instills the DMSO solution into the bladder through a catheter or syringe, allows it to remain for about 15 minutes, and the patient then voids it by urinating. This treatment must be performed under medical supervision.
What is the CAS number of pure DMSO?
The CAS number of dimethyl sulfoxide is 67-68-5.
