Methanol and isopropyl alcohol both have industrial uses, and both are toxic to humans and other mammals. Their chemical structures and other properties differ in several ways. These compounds are not the same.
In common usage, "alcohol" means ethanol–the drinkable, mind-altering substance found in vodka and beer. However, in chemistry, "alcohol" refers to a hydroxyl group, consisting of hydrogen bonded to oxygen, attached to a carbon group, according to Georgia State University. Remembering that makes it easier to understand the difference between methanol and isopropyl alcohol.
Methanol consists of a methyl group (a carbon with three hydrogens attached) connected to a hydroxyl group. The formula is CH3OH.
Methanol functions as a solvent in laboratories. Manufacturers add it to ethanol to create denatured alcohol, undrinkable by design, for use as a fuel or cleanser. Ingesting even a tiny amount of methanol can cause permanent blindness or death, according to NIH Medline.
Isopropyl Alcohol Structure
Isopropyl alcohol, also known as isopropanol, consists of an isopropyl group–this can be described as two methyl groups attached to a carbon–bonded to a hydroxyl (OH) group. The formula for isopropyl alcohol is C3H7OH.
Isopropyl Alcohol Properties
Isopropyl alcohol, frequently used as a solvent and a disinfectant, has less severe toxicity than methanol, but can also cause poisoning. It catches fire very easily.
Methanol and isopropyl alcohol both have toxic properties and should never be taken internally.
About the Author
Eri Luxton holds a B.A. in liberal arts, an M.F.A. in creative writing, a first aid certification and a biomedical ethics certificate. She has worked as an English teacher overseas and as a local volunteer in first aid and in technology troubleshooting. Luxton mentors students in chemistry and physics while studying toward a pre-health sciences degree.
Brand X Pictures/Brand X Pictures/Getty Images