Ionic liquids of superior thermal stability. Validation of PPh as an organic cation of impressive thermodynamic durability.

Recent work by Wasserscheid, suggests that PPh is an organic molecular ion of truly exceptional thermal stability. Herein we provide data that cements that conclusion: specifically, we show that aliphatic moieties of modified PPh -based cations incorporating methyl, methylene, or methine C-H bonds burn away at high temperatures in the presence of oxygen, forming CO, CO, and water, leaving behind the parent ion PPh . The latter then undergoes no further reaction, at least below 425 °C.