Isopropyl Alcohol (IPA)
Ordinary distillation stops at 87.7% because the water refuses to leave. Everything above that — anhydrous, pharmacopoeial, semiconductor grade — requires a different separation entirely, and that is what the grade ladder is really about.
Molecular Structure
What is Isopropyl Alcohol (IPA)?
Isopropyl alcohol is a secondary alcohol — a hydroxyl on the middle carbon of a three-carbon chain. It is fully miscible with water and with most organic solvents, dissolves a wide range of oils, resins and salts, evaporates cleanly and leaves no residue, and has low chronic toxicity. That combination is why it is the default cleaning solvent across industries that share almost nothing else.
It also forms an azeotrope with water at 87.7% by weight, boiling at 80.3 °C. No amount of ordinary fractionation gets past that point, so anhydrous grades require azeotropic distillation with an entrainer, molecular sieve adsorption, or membrane pervaporation. That step is the real distinction between a 99% commercial grade and a 99.9% anhydrous one.
Production is by hydration of propylene, either indirectly through sulphuric acid esters or directly over an acid catalyst, and a smaller volume by hydrogenating acetone. Grades run from 70% aqueous through 99.7% technical to pharmacopoeial and semiconductor grades specified in parts per billion.
Seventy per cent IPA disinfects better than ninety-nine per cent. Water is needed to denature bacterial proteins and to slow evaporation enough for adequate contact time — concentrated alcohol coagulates the outer protein layer and flashes off before it penetrates. Buying the highest purity for a disinfection application makes it work less well.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
A hydroxyl group on the middle carbon of propane. The short chain keeps it fully water-miscible while the alkyl groups give enough organic solvency to lift oils and resins — the balance that makes it a universal cleaning solvent.
Skeletal structure — secondary alcohol on a three-carbon chain
Structural Identity
- IUPAC NamePropan-2-ol
- Common namesIPA, isopropanol, rubbing alcohol
- Molecular FormulaC₃H₈O
- Molecular Weight60.10 g/mol
- Functional groupSecondary alcohol
- MiscibilityWater and most organic solvents
- Water azeotrope87.7 wt%, boils 80.3 °C
- Anhydrous routeAzeotropic distillation, sieve or membrane
- Made fromPropylene hydration; acetone hydrogenation
- CAS Number67-63-0
- InChI KeyKFZMGEQAYNKOFK-UHFFFAOYSA-N
Product Specifications
Chelora supplies Isopropyl Alcohol (IPA) in standard and custom grades. Contact us for specification sheets tailored to your process.
| Chemical name | Isopropyl alcohol |
|---|---|
| CAS Number | 67-63-0 |
| Molecular formula | C₃H₈O |
| Molecular weight | 60.10 g/mol |
| Purity (min) | ≥ 99.70 wt%; ≥ 99.9% for anhydrous grades |
| Water (max) | ≤ 0.20 wt%; ≤ 0.05% anhydrous (Karl Fischer) |
| Acidity as acetic acid (max) | ≤ 0.002 wt% |
| Colour (max) | ≤ 5 Pt-Co (Hazen) |
| Specific gravity | 0.7845 – 0.7865 at 20/20 °C |
| Distillation range | 82.0 – 83.0 °C |
| Non-volatile residue (max) | ≤ 5 ppm wt |
| Acetone (max) | ≤ 0.02 wt% |
| Methanol (max) | ≤ 0.02 wt% |
| Di-isopropyl ether (max) | ≤ 0.05 wt% |
| Benzene, USP/EP grade (max) | ≤ 2 ppm wt |
| Peroxides as H₂O₂ (max) | ≤ 5 ppm wt |
| Metals, electronic grade | Na, Fe, Ca and others to ppb, specified separately |
| Flash point | 12 °C (closed cup) |
| Autoignition temperature | 399 °C |
| Transport classification | UN 1219, Class 3, PG II |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Isopropyl Alcohol (IPA).
Cleaning & Disinfection
Surface, medical and equipment disinfection, usually as 70% aqueous solution, plus hand sanitiser formulation where the WHO reference uses 75% by volume.
Electronics Cleaning
Wafer rinse, flux removal and precision optics cleaning, using semiconductor grades specified for metals and particles in parts per billion.
Printing Fountain Solution
Dampening solution in offset lithography, controlling surface tension so that the non-image areas of the plate reject ink.
Pharmaceutical Processing
Crystallisation, wet granulation and API isolation under USP and EP grades, plus use as an excipient in liquid formulations.
Coatings & Inks
A co-solvent and viscosity reducer in inks, wood coatings and adhesives, and a common component of thinner blends.
De-icer & Extraction
Fuel line antifreeze, windscreen and aircraft de-icing formulations, and an extraction solvent in natural product and speciality chemical processing.
Why source Isopropyl Alcohol (IPA) through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation — no grey-market supply.
Grade Flexibility
Technical, anhydrous, USP/EP and electronic grades supplied, plus 70% aqueous. We certify water, related compounds and — for pharmacopoeial grades — benzene, which is the specification that actually separates the grades.
Full Documentation
CoA, SDS, UN 1219 transport documents, REACH compliance, and USP/EP or semiconductor documentation where the grade requires it.
Logistics Support
Experienced in flammable solvent logistics — dedicated road tankers and ISO tanks with bonding and earthing, plus drums and IBCs, with segregation for pharmacopoeial and electronic grades, for Indian and international delivery.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Store in earthed and bonded tanks with pressure/vacuum relief and flame arrestors. Flash point is 12 °C, so ignitable vapour is present at most working temperatures.
- Bond and earth every transfer connection and avoid splash filling. Alcohols generate static readily and the flammable range is wide.
- Keep containers closed. IPA is hygroscopic and absorbs water from humid air quickly, which takes an anhydrous grade off specification within hours of being left open.
- Segregate pharmacopoeial and electronic grades completely, with dedicated hoses, pumps and lines. There is no way to recover a contaminated lot, and both grades are bought precisely on the impurities that cross-contamination introduces.
- Test for peroxides on material that has been stored long or exposed to air. Secondary alcohols form peroxides slowly, and concentrating them by evaporation is the risk scenario.
- Match concentration to purpose. For disinfection, 70% is the correct product, and specifying a higher purity actively reduces efficacy.
- Exclude strong oxidisers, particularly nitric and chromic acid, which react violently with alcohols.
- Ventilate to keep vapour below the lower flammable limit rather than merely below the exposure limit, and classify the area for electrical equipment.
- Provide eyewash and safety showers, use non-sparking tools, and label containers clearly, particularly where several concentrations are in use on one site.
Hazard Summary
Classification: Flam. Liq. 2 (H225), Eye Irrit. 2 (H319), STOT SE 3 (H336, may cause drowsiness or dizziness). IPA has low chronic toxicity and is not classified as a carcinogen, mutagen or reproductive toxicant.
Flammability is the practical hazard: a flash point of 12 °C means ignitable vapour at most working temperatures, with a flammable range of 2.0 to 12.7%. Alcohol fires burn with a pale, sometimes nearly invisible flame in daylight, which has caused people to walk into them. Foam suitable for polar solvents is required — ordinary hydrocarbon foam is broken down by alcohol.
A note on IARC: IARC lists isopropyl alcohol manufacture using strong acids as carcinogenic to humans, based on nasal cancers among workers in older plants. That classification applies to the historic process and its by-products, principally di-isopropyl sulphate, and not to isopropyl alcohol itself, which IARC does not classify as carcinogenic. Buyers searching the IARC database sometimes encounter this and reasonably misread it.
Health: irritating to eyes, and vapour causes drowsiness and dizziness at high concentration. Ingestion is significantly more toxic than ethanol and causes central nervous system depression; denatured and industrial grades must never be stored where they could be mistaken for a beverage.
Hygroscopic: IPA absorbs atmospheric moisture readily. This is a specification risk on anhydrous grades rather than a safety issue, but it is the most common reason a compliant lot fails on receipt.
Peroxides: secondary alcohols form peroxides slowly on air exposure. Test before distilling or evaporating material that has been stored for an extended period.
Incompatibilities: strong oxidisers including nitric acid, chromic acid and hydrogen peroxide; also aluminium at elevated temperature.
PPE minimum: chemical goggles, resistant gloves, antistatic clothing and footwear at transfer points, with respiratory protection where ventilation cannot control vapour.
Consult the full SDS for exposure limits, spill containment, emergency response and disposal before any use.
Frequently Asked Questions
Technical and commercial questions about Isopropyl Alcohol (IPA) sourcing and specifications.
What is isopropyl alcohol used for?
Cleaning and disinfection is the largest and most visible use, from hospital surface wipes and hand sanitiser to industrial equipment cleaning. Electronics is a demanding segment — wafer rinsing, flux removal and optics cleaning use grades specified in parts per billion for metals. Beyond those, IPA is the dampening solution in offset lithographic printing, a pharmaceutical processing solvent under USP and EP monographs, a co-solvent in coatings and inks, and the active ingredient in de-icers and fuel line antifreeze.
Why is 70% IPA a better disinfectant than 99%?
Because water is part of the mechanism. Alcohol kills bacteria by denaturing their proteins, and that reaction needs water present to proceed properly. Applied neat, concentrated alcohol coagulates the outer protein layer of the cell so quickly that it forms a barrier, and the alcohol never reaches the interior. Concentrated alcohol also evaporates very fast, often before the contact time needed for disinfection has elapsed. A 70% solution penetrates further, keeps the surface wet longer, and denatures more completely. Anyone specifying the highest available purity for a disinfection application is paying more for a product that works less well.
Why can IPA not be distilled above 87.7%?
Because at that composition it forms an azeotrope with water. The vapour coming off a boiling mixture at 87.7% IPA has exactly the same composition as the liquid, so no further separation happens no matter how many theoretical plates the column has — the mixture behaves as if it were a single substance boiling at 80.3 °C. Getting past it requires changing the system: azeotropic distillation with a third component that breaks the azeotrope, adsorption onto molecular sieves that admit water but not IPA, or membrane pervaporation. That extra unit operation is the real cost difference between a commercial 99% grade and an anhydrous one.
What grades of IPA are there and how do they differ?
Four broad tiers. Aqueous grades, usually 70%, are made for disinfection and are not a diluted version of anything — the concentration is the specification. Technical grade at 99.7% covers cleaning, coatings and general industrial use. Pharmacopoeial grade meets the USP or EP monograph, which adds identification tests and limits on related compounds including acetone, methanol, di-isopropyl ether and benzene, and requires manufacturing and storage controls that prevent cross-contamination. Electronic or semiconductor grade is specified on metals, anions and particle counts in parts per billion, with packaging and filtration to match — the organic assay is almost incidental at that level.
Why does the pharmacopoeial specification include a benzene limit?
Because of how anhydrous IPA has historically been made. Breaking the water azeotrope by azeotropic distillation requires an entrainer, and benzene was the traditional choice before its carcinogenicity led to substitution with cyclohexane and other agents. Trace entrainer can carry through into the product, so pharmacopoeial monographs specify a benzene limit — typically 2 parts per million — as a control on that route. Modern anhydrous IPA is generally made by molecular sieve or membrane drying and contains no benzene at all, but the test remains in the monograph and remains worth seeing on the certificate for any pharmaceutical use.
What documentation does Chelora provide?
Every shipment includes a Certificate of Analysis covering purity, water, acidity, colour, specific gravity, distillation range, non-volatile residue, acetone, methanol and di-isopropyl ether, with benzene and full monograph testing for USP and EP grades and metals and particle data for electronic grades; a Safety Data Sheet to GHS and REACH format; UN 1219 Class 3 dangerous goods documentation; an origin certificate; and destination-market or pharmacopoeial certificates where required.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Isopropyl Alcohol (IPA) grade, volume, logistics, documentation, and lead times. We respond within one business day.
