Aprotic - new to me

kw: words

Reading a report I found the word aprotic. I could guess that it refers to a chemical that cannot donate a proton, thus limiting the kinds of reactions it can undergo. Such substances make good solvents, good hosts for oxidation-reduction reactions (which operate by trading protons). A little searching confirmed my horseback hunch.

Digging around in Google Books, the earliest reference I could find is in a 1953 volume, Non-Aqueous Solvents by Audrieth and Kleinberg (seemingly earlier uses in print are instances of typos or mistaken OCR, such as 1907 for 1987. Of course the Google Books project hasn't snarfed up everything just yet).

Early usage focused on nonpolar solvents such as benzene, or non-H-bearing chemicals such as sulfur dioxide, but in more recent years polar chemicals that hold their hydrogens very tightly have been included, such as phosphazenes, which are full of NH₂ groups but do not permit any hydrogen ions to be removed. Acetone and DMSO are considered aprotic, polar solvents.

A useful word, in certain contexts, and an interesting one to have learned.