Isopropyl Alcohol (CAS 67-63-0): Applications, Cleaning Mechanism and Solvent Selection Guide
September 30, 2026 · Sourcing Guide
Summary. Isopropyl alcohol (IPA, isopropanol, CAS 67-63-0, C3H8O, MW 60.10) is a clear, water-miscible secondary alcohol solvent with a boiling point of 82.5 °C, a low surface tension and moderate evaporation rate. Its main uses are semiconductor, printed circuit board and precision component cleaning and water-displacement drying, 70 % disinfectant and sanitising products, pharmaceutical processing and crystallisation, coatings, inks and adhesive formulations, cosmetics and personal care, de-icing and windscreen washer fluids, and as a feedstock for acetone, isopropyl acetate and isopropyl esters. IPA is an ICH Q3C Class 3 residual solvent (limit 5000 ppm), and electronic grade material is specified for low water, low metals and low particles. This guide summarises specifications, manufacturing, application mechanisms, downstream products and comparisons with ethanol, acetone, ethyl acetate and n-hexane.
Basic information
| Item | Value |
|---|---|
| Product name | Isopropyl alcohol (isopropanol, 2-propanol) |
| CAS number | 67-63-0 |
| Molecular formula / MW | C3H8O / 60.10 g/mol |
| Appearance | Clear colourless liquid, characteristic alcohol odour |
| Assay | ≥99.9 % (industrial); ≥99.9 % electronic grade; pharmaceutical grade available |
| Water content | ≤0.1 % (industrial); ≤0.05 % or lower for electronic grade |
| Boiling point | 82.5 °C |
| Density (20 °C) | 0.785 g/cm³ |
| Flash point | 11.7 °C (flammable liquid) |
| Water solubility | Fully miscible; azeotrope with water at ≈80.4 °C |
| Surface tension | ~21.7 mN/m (low, supports water displacement) |
| ICH Q3C | Class 3 residual solvent, concentration limit 5000 ppm |
| Packaging | 160 kg drum, 1000 kg IBC, ISO tank |
| HS code | 2905.12 (confirm with local customs) |
| Storage | Cool, shaded, well ventilated; sealed to limit moisture pickup; no ignition sources |
| Main uses | Electronics cleaning and drying; disinfectant; pharmaceutical, coatings and cosmetics solvent; de-icing |
1. Product overview
IPA is valued for combining complete water miscibility with lipophilic solvency: the hydroxyl group gives hydrogen bonding and water compatibility, while the isopropyl group dissolves oils, fluxes, resins and greases. It has a low surface tension, evaporates cleanly without residue, and is much less toxic than methanol, n-hexane or chlorinated solvents, which makes it the default cleaning alcohol in electronics and medical applications.
2. Manufacturing (brief)
Industrial IPA is produced by hydration of propylene. In the indirect (sulfation) process, propylene reacts with sulfuric acid to form isopropyl hydrogen sulfate, which is hydrolysed and distilled. In the direct process, propylene and water are passed over a solid acid catalyst at elevated pressure, and IPA is separated by distillation. A secondary route is hydrogenation of acetone. Water is removed by azeotropic or extractive distillation or by molecular sieve drying to obtain anhydrous grades, and electronic grade material receives additional distillation, ion exchange and filtration to control metals and particles.
3. Application principles
- Dual solvency. The molecule simultaneously dissolves polar and non-polar soils, so it removes flux, oils, fingerprints and ionic residues in one step without leaving water or organic residue behind.
- Water-displacement (Marangoni) drying. Because IPA is miscible with water and has a lower surface tension, it displaces the water film on a wafer, lens or metal surface and then evaporates, preventing water spots and corrosion. This is the basis of IPA vapour drying in semiconductor and precision optics lines.
- Disinfection. A concentration of about 70 % (v/v) in water is the standard disinfectant strength: water is needed to penetrate cell walls and denature proteins, while the alcohol dissolves lipids and dehydrates the cell. Higher concentrations evaporate too quickly and act less effectively.
- Solvent for formulation. IPA is a Class 3 residual solvent, has moderate evaporation, good resin compatibility and low odour, so it is used as a co-solvent in waterborne coatings, inks and cosmetic formulations.
- Feedstock chemistry. Dehydrogenation of IPA gives acetone, and esterification gives isopropyl acetate and isopropyl esters; the alcohol also serves as a hydrogen source in transfer hydrogenation.
4. Application areas in detail
4.1 Electronics and precision cleaning
IPA is the standard cleaning and drying solvent for semiconductor wafers, photomasks, printed circuit boards, connectors, hard disk components, optical lenses and precision metal parts. Downstream products include defluxing agents for PCB assembly, stencil and solder-paste cleaning fluids, wafer drying systems, and lens and screen cleaning products. Electronic grade IPA is specified with low water, low metal ions, low particles and controlled UV absorbance.
4.2 Medical disinfection and hygiene
70 % IPA solutions are the basis of disinfectant wipes, hand sanitising gels, surface disinfectants, pre-injection swabs and instrument cleaning fluids. IPA is also used in pharmaceutical manufacturing as a cleaning agent for equipment and cleanrooms, as a solvent for API crystallisation, granulation and tablet coating, and in the preparation of tinctures and liniments.
4.3 Coatings, inks and adhesives
IPA is a co-solvent and dilution solvent in waterborne and solvent-borne coatings, printing inks, flexographic and gravure ink systems, adhesives and sealants, where it improves substrate wetting, controls drying and prevents blushing. It is also used in dampening solutions for offset printing and in screen-printing and pad-printing inks.
4.4 Cosmetics and personal care
IPA is used in astringent toners, aftershave lotions, deodorants, nail products and fragrance concentrates as a fast-evaporating carrier, and as a processing solvent for isopropyl myristate and isopropyl palmitate, the emollient esters widely used in skin and hair care.
4.5 Automotive, industrial and household fluids
Typical downstream products include windscreen washer fluids and de-icers, fuel-line antifreeze (dry gas) additives, degreasers, glass cleaners, and electronic contact cleaners, where IPA provides fast evaporation and low residue.
4.6 Chemical intermediate
IPA is feedstock for acetone (which in turn feeds methyl methacrylate, bisphenol A and methyl isobutyl ketone production), isopropyl acetate, isopropylamine derivatives, and a range of isopropyl esters used as solvents and emollients.
5. Comparison with alternative solvents
| Solvent | Difference vs IPA | Practical implication |
|---|---|---|
| Ethanol (CAS 64-17-5) | Slightly lower boiling point, weaker solvency for oils and resins | Ethanol is preferred for food and beverage contact; IPA cleans flux, oils and grease more effectively |
| Acetone (CAS 67-64-1) | Much lower flash point (−20 °C), attacks many plastics, stronger for polar resins | IPA is safer on plastic parts and has a lower evaporation loss; acetone is faster but more aggressive |
| Ethyl acetate (CAS 141-78-6) | Not fully water-miscible, more flammable | IPA is the better choice where water displacement or water-borne compatibility is needed |
| n-Hexane | Non-polar, neurotoxic, strict exposure limits | IPA offers better worker safety and cleaning performance for polar and mixed soils |
| Methanol | Toxic, metabolised to formic acid | IPA is much safer for cleaning and formulation |
| Chlorinated solvents | Stronger for heavy oils and cured polymers, higher toxicity | IPA is preferred for electronics and medical cleaning where residue and toxicity matter |
IPA advantages: water miscible yet lipophilic, low surface tension and clean evaporation, low toxicity, ICH Class 3 status, broad availability. Limitations: hygroscopic (moisture pickup reduces cleaning strength over time), flammable, and it can swell or stress some elastomers and plastics.
6. Safety, storage and regulatory notes
IPA is flammable (flash point 11.7 °C) and must be handled with grounding, bonding and ventilation. Occupational limits are typically around 200–400 ppm (8-hour TWA) depending on jurisdiction. Because it is miscible with water, drums and storage tanks should be kept sealed to prevent moisture pickup, which would lower the assay and can cause haze or water marks in cleaning applications. IPA is not a controlled substance and is transported as a flammable liquid (UN 1219, Class 3).
FAQ
Q1. What is isopropyl alcohol used for? Electronics and precision cleaning and drying, 70 % disinfectant products, pharmaceutical processing, coatings, inks and adhesives, cosmetics, de-icing fluids, and as a feedstock for acetone and isopropyl esters.
Q2. Why is 70 % IPA used for disinfection instead of 99 %? About 70 % in water gives the best balance: water penetrates the cell wall and denatures proteins while the alcohol dissolves lipids and dehydrates the cell. Higher concentrations evaporate too fast and are less effective.
Q3. Why is IPA used for wafer and PCB drying? It is miscible with water and has a low surface tension, so it displaces the residual water film and evaporates without leaving water spots or corrosion — the basis of IPA and Marangoni drying.
Q4. What is the residual solvent classification of IPA? IPA is an ICH Q3C Class 3 solvent with a concentration limit of 5000 ppm.
Q5. IPA or ethanol for cleaning? IPA generally removes flux, oils and greases more effectively and is less hygroscopic in use, while ethanol is preferred where food-contact or beverage regulations apply.
Q6. Does IPA attack plastics? It is compatible with most metals, glass and many plastics, but it can stress or swell some elastomers, polycarbonate and certain acrylics; compatibility testing is recommended before use.
Q7. How should IPA be stored? In sealed, cool, shaded, well-ventilated areas away from ignition sources, with moisture ingress controlled to maintain assay; electronic grade material should be kept under nitrogen where specified.
Q8. What is the HS code for isopropyl alcohol? HS 2905.12; confirm the final classification with the importing customs authority.
Keywords: isopropyl alcohol, IPA, isopropanol, CAS 67-63-0, electronic grade IPA supplier, semiconductor cleaning solvent, PCB defluxing solvent, water displacement drying, 70% alcohol disinfectant raw material, pharmaceutical solvent, ICH Q3C Class 3 solvent.