● What to call (CH3)2CH(OH)? The November 2012 issue of Chem13 News has “isopropanol” listed in the materials for the Miniature Whoosh Bottle Demonstration. The question was raised whether this was an appropriate name or whether “2-propanol” or “isopropyl alcohol” would be the better choice. A quick look in the 12th edition of The Merck Index revealed “isopropyl alcohol” as a major heading followed by pseudonyms “2- propanol, isopropanol, secondary propyl alcohol, dimethyl carbinol,” and “petrohol.” One can also find “rubbing alcohol” (70% isopropanol) and “isopropyl alcohol” (91% isopropanol) at local pharmacies. So what should we call this substance?
As an instructor, I teach students the IUPAC system of nomenclature because this system allows one to deduce the structural formula of some ominous-looking named substances such as 2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane. I also teach students common names when appropriate so they are aware that a substance can go by more than one name. A good example I use is that acetic acid is the common name for ethanoic acid. It is important to make our subject relevant to the students’ everyday lives. In talking about ethanoic acid or acetic acid, I would point out that vinegar is a dilute solution of acetic acid.
While I likely would not call it 2-propanol, dimethyl carbinol or petrohol, the use of isopropanol is acceptable. And actually right now there is a bottle labeled — by the manufacturer — as such in my lab.