What Is the CAS Number for Isopropyl Alcohol?
Isopropyl alcohol carries the CAS number 67-63-0. The systematic IUPAC name is propan-2-ol, and the compound is also traded as isopropanol, 2-propanol and, in consumer packaging, rubbing alcohol. It is a colourless, flammable liquid with a pungent odour, a molecular formula of C3H8O and a molecular weight of 60.10 g/mol. Because it mixes freely with water and with most organic solvents, it has become one of the most widely used solvents in industry, healthcare and consumer products.
The hydroxyl group sits on the middle carbon of the three-carbon chain, and this secondary structure explains much of the behaviour that buyers rely on: fast evaporation, strong solvency for polar and moderately non-polar soils, and low residue after drying.
Physical Properties and Solvency
| Property | Typical value |
|---|---|
| CAS number | 67-63-0 |
| Formula | C3H8O |
| Molecular weight | 60.10 g/mol |
| Boiling point | 82.6 °C |
| Melting point | -89.5 °C |
| Density at 20 °C | 0.786 g/cm3 |
| Flash point (closed cup) | 12 °C |
| Vapour pressure at 20 °C | 4.4 kPa |
| Water solubility | Miscible in all proportions |
| Transport classification | UN 1219, Class 3, Packing Group II |
Isopropyl alcohol is a polar organic molecule that is miscible with water, ethanol and chloroform. That wide compatibility lets it dissolve ethyl cellulose, polyvinyl butyral, many oils, alkaloids and natural resins. The combination of water miscibility and good solvency makes it a practical choice for cleaning formulations, coatings and extraction processes where residue-free drying matters.
Industrial and Everyday Applications
Cleaning and degreasing: it removes light grease, oils, dust and flux residues from glass, optical parts, printed circuit boards, connectors and metal components, and it evaporates quickly without leaving a film.
Electronics and precision assembly: technical grades are used to clean wafers, hard-disk parts, printer components and heat sinks, and to remove thermal paste during service work.
Disinfection: aqueous solutions in the 60% to 70% by volume range are used for surface disinfection and hand hygiene in medical and food-handling environments.
Coatings, inks and adhesives: it dilutes lacquers, PVC adhesives, dyes and printing inks, and it acts as a carrier solvent in marking and coating systems.
Extraction and laboratory work: the solvent is used for the precipitation and washing of nucleic acids and for general sample preparation.
Cold-weather and fuel uses: it de-ices locks and windscreens, is added to washer fluid, and dissolves water or ice that has entered fuel lines.
Process aids: it serves as an anti-foam agent and as an ingredient in rinse-aid formulations.
Grades and Selection Guidance
Industrial grade: 99.5% minimum assay, used for general cleaning and as a carrier solvent.
Electronic and precision-cleaning grade: 99.9% minimum assay with low non-volatile residue and controlled water content.
Pharmaceutical grade: manufactured to pharmacopoeial monographs with documented impurity profiles and full batch traceability.
Anhydrous grade: water content held at or below 0.05% for moisture-sensitive reactions and formulations.
Blended grades: ready-to-use aqueous solutions with a defined alcohol content for disinfection programmes.
Safety, Storage and Compliance
Isopropyl alcohol is a flammable liquid: vapour can form explosive mixtures with air and can travel to a remote ignition source. It is also an eye and skin irritant at high concentrations, and ingestion is dangerous. Keep the material away from open flames, sparks and hot surfaces, and work in well-ventilated areas with bonding and grounding during transfers.
Store in tightly closed, grounded containers in a cool, dry place, separated from strong oxidising agents.
Use chemical goggles and nitrile or butyl gloves; for confined spaces, monitor vapour levels and wear suitable respiratory protection.
Supply documentation: certificate of analysis, safety data sheet and technical data sheet accompany every lot, and the product is registered under REACH for European deliveries.
Frequently Asked Questions
Q: What is the CAS number of isopropyl alcohol?
The CAS number of isopropyl alcohol is 67-63-0.
Q: What other names are used for isopropyl alcohol?
Other names include isopropanol, 2-propanol, propan-2-ol and rubbing alcohol.
Q: Is isopropyl alcohol miscible with water?
Yes. It is miscible with water, ethanol and chloroform in all proportions.
Q: What is isopropyl alcohol used for?
It is used for cleaning glass, lenses and electronics, as a solvent for inks and adhesives, for disinfection, in extraction processes, and as a de-icer and antifreeze additive.
Q: Is isopropyl alcohol flammable?
It is a flammable liquid with a closed-cup flash point of 12 °C, so it must be kept away from ignition sources and handled with bonding and grounding.
Q: What does isopropyl alcohol dissolve?
It dissolves ethyl cellulose, polyvinyl butyral, many oils, alkaloids, natural resins, dyes and printing inks.