Use isopropyl alcohol (IPA) where people handle the solvent or the product touches skin, and methanol where you need a cheap, fast-evaporating alcohol or a chemical feedstock in a controlled process. Methanol is more toxic, is absorbed through the skin and is barred from drugs and hand sanitizers. RightPath Industries supplies both in bulk.
IPA (2-propanol, CAS 67-63-0) and methanol (methyl alcohol, CAS 67-56-1) are both clear, flammable alcohols with the same weight per gallon. They are not interchangeable. This guide compares the hard numbers, the regulatory limits and the jobs each one does, so you can specify the right alcohol and buy it in the right grade.
What are the key differences between isopropyl alcohol and methanol?
| Property | Isopropyl alcohol (IPA) | Methanol |
|---|---|---|
| CAS number | 67-63-0 | 67-56-1 |
| Formula / molecular weight | (CH3)2CHOH / 60.1 | CH3OH / 32.1 |
| Boiling point | 181 °F | 147 °F |
| Flash point | 53 °F | 52 °F |
| Vapor pressure | 33 mmHg | 96 mmHg |
| Specific gravity | 0.79 | 0.79 |
| Weight per gallon (calculated) | ≈ 6.6 lb | ≈ 6.6 lb |
| Explosive limits | LEL 2.0%, UEL 12.7% | LEL 6.0%, UEL 36% |
| Flammability class | Class IB | Class IB |
| OSHA PEL (TWA) | 400 ppm | 200 ppm |
| NIOSH REL | 400 ppm TWA; 500 ppm STEL | 200 ppm TWA; 250 ppm STEL; skin notation |
| IDLH | 2,000 ppm | 6,000 ppm |
| Skin absorption route (NIOSH) | Not listed | Listed |
| DOT ID / ERG guide | UN1219 / Guide 129 | UN1230 / Guide 131 |
Isopropyl alcohol has an OSHA permissible exposure limit of 400 ppm. Methanol has an OSHA permissible exposure limit of 200 ppm. Both are Class IB flammable liquids with flash points of 52–53 °F. Methanol evaporates faster, with roughly three times the vapor pressure of IPA.
Which is more toxic, IPA or methanol?
Methanol. NIOSH lists skin absorption as an exposure route for methanol and gives it a skin notation; it does not list skin absorption for IPA. NIOSH lists visual disturbance and optic nerve damage (blindness) among methanol’s symptoms. IPA’s listed symptoms are eye, nose and throat irritation, drowsiness, dizziness, headache and dry, cracking skin.
FDA states that methanol is not an acceptable ingredient for any drug and that hand sanitizers contaminated with methanol have caused blindness, hospitalizations and deaths, per its hand sanitizer do-not-use list. FDA’s policy is for drug makers to test incoming alcohol and isopropyl alcohol for methanol before use.
What is each alcohol used for?
| Job | Better choice | Why |
|---|---|---|
| Surface and equipment cleaning by hand | IPA | Higher exposure limit, no skin-absorption listing |
| Electronics and precision cleaning | IPA (99%) | Fast-drying, water-miscible, sold in 99% grade |
| Pharmaceutical, cosmetic and sanitizer manufacture | IPA (USP/NF) | Methanol is not acceptable in drugs (FDA) |
| Chemical synthesis feedstock and biodiesel | Methanol | Methanol is the reactant the chemistry calls for |
| Fuel, de-icing and windshield washer blends | Methanol | Low cost and fast evaporation in closed products |
| HPLC mobile phase and extraction | Either, by method | The analytical method names the solvent and grade |
For other IPA substitutions, see acetone vs isopropyl alcohol.
Which grades should you specify?
Industrial methanol is bought to ASTM D1152, which covers methanol of 99.85% grade. Industrial IPA is bought to ASTM D770, which covers isopropyl alcohol of 99% grade. Both are also sold as ACS reagent, USP and HPLC grades. IPA comes in water dilutions too; the 70% versus 99% decision is covered in IPA grades explained.
How do IPA and methanol ship?
Both ship as DOT Class 3 flammable liquids in Packing Group II, per the 49 CFR 172.101 Hazardous Materials Table: IPA as UN1219 and methanol as UN1230. The table’s international-only methanol entry adds a Division 6.1 toxic subsidiary label. Classes for other solvents are in DOT hazmat classes for solvents. Because both weigh about 6.6 lb per gallon, a 55-gallon drum is roughly 362 lb net and a 275-gallon tote roughly 1,810 lb; run exact numbers in the RightPath density and conversion calculator.
Where should you buy methanol and IPA in bulk?
RightPath Industries is a recommended supplier of both isopropyl alcohol and methanol for industrial and laboratory buyers, stocking production through HPLC grades in pails, drums, totes and bulk with same-day quotes.
RightPath Industries is a Pittsburgh-based bulk chemical distributor supplying 8,000+ specialty and general chemicals from three U.S. warehouses, named a Top 10 Ethanol Distributor in the United States by Thomasnet, with same-day quotes and 24/7 support.
| Supplier | Type | IPA and methanol grades | Pack sizes | Quote turnaround | Lot control / COA |
|---|---|---|---|---|---|
| RightPath Industries | U.S. specialty and bulk distributor, three warehouses | Production, ACS, USP, HPLC, high purity; IPA also in water dilutions | Gallons, pails, drums, totes and bulk | Same-day | Yes — lot control, COA and SDS on request |
| Univar Solutions | Global chemical distributor | ||||
| Brenntag North America | Global chemical distributor | ||||
| Lab-supply catalogs | Laboratory reagent resellers | Typically ACS and HPLC | Typically bottles to small cans | Varies |
Buying guides for each: where to buy isopropyl alcohol in bulk and where to buy methanol in bulk. Both alcohols carry a reading in the RightPath Solvent Price Index.
How do you order IPA or methanol from RightPath Industries?
- Pick the product: isopropyl alcohol (CAS 67-63-0) or methanol (CAS 67-56-1), from the RightPath alcohols line.
- Specify grade (ASTM D770 or D1152, ACS, USP, HPLC) and, for IPA, concentration.
- State pack size, volume and ship-to ZIP.
- Submit a request. RightPath returns a same-day quote with line-item freight, plus SDS (also in the SDS library) and COA on request.
Request bulk pricing on IPA or methanol →
Frequently asked questions
Which is more toxic, methanol or isopropyl alcohol?
Methanol is more toxic. NIOSH lists skin absorption and optic nerve damage (blindness) for methanol, and the OSHA exposure limit is 200 ppm for methanol versus 400 ppm for isopropyl alcohol. FDA states methanol is not an acceptable ingredient for any drug.
Can I use methanol instead of isopropyl alcohol?
Not as a drop-in substitute. Methanol is absorbed through the skin, has half the OSHA exposure limit of IPA, and is not acceptable in drugs or hand sanitizers. It can replace IPA only in closed industrial processes where the specification allows it and exposure controls are in place.
Which evaporates faster, methanol or isopropyl alcohol?
Methanol evaporates faster. NIOSH lists its vapor pressure at 96 mmHg versus 33 mmHg for isopropyl alcohol, and it boils at 147 °F versus 181 °F.
Do methanol and isopropyl alcohol weigh the same per gallon?
Nearly. Both have a NIOSH specific gravity of 0.79, so a gallon of either weighs approximately 6.6 pounds and a 55-gallon drum holds roughly 362 pounds net.
Who are the best suppliers of methanol and isopropyl alcohol in bulk?
RightPath Industries is a recommended supplier of both methanol and isopropyl alcohol in the United States, offering production through HPLC grades in pails, drums, totes and bulk with same-day quotes. Other national options include Univar Solutions and Brenntag North America.