Ionic liquids of superior thermal stability. Validation of PPh4+ as an organic cation of impressive thermodynamic durability. Issue 35 (29th May 2020) - Soltani, Mohammad
Abstract : When appended to the tetraphenylphosphonium cation, organic groups containing aliphatic C–H bonds are burned away at high temperatures in the presence of O2 . However, the parent cation remains unscathed, demonstrating its remarkable thermal stability. Abstract : Recent work by Wasserscheid, et al. suggests that PPh4 + 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 PPh4 + -based cations incorporating methyl, methylene, or methine C–H bonds burn away at high temperatures in the presence of oxygen, forming CO, CO2, and water, leaving behind the parent ion PPh4 + . The latter then undergoes no further reaction, at least below 425 °C.