TPAP

Tetrapropylammonium perruthenate is the chemical compound described by the formula N(C3H7)4RuO4. Sometimes known as the Ley-Griffith reagent, this ruthenium compound is used in organic synthesis. This salt consists of the tetrapropylammonium] cation and the perruthenate, RuO4- anion. Ruthenium tetroxide is a highly aggressive oxidant, but its one-electron reduced derivative is a mild oxidizing agent for the conversion of alcohols to aldehydes.[2] This oxidizing agent can also be used to oxidize primary alcohols all the way to the carboxylic acid through a higher catalyst and co-oxidant loading along with the addition of two equivalents of water. The mechanism works by a normal oxidation of the alcohol to the aldehyde followed by hydration, and a final oxidation.[3]

The oxidation generates water that can be removed by adding molecular sieves. TPAP is expensive but it can be used in catalytic amounts. The catalytic cycle is maintained by adding a stoichiometric amount of a co-oxidant such as N-methylmorpholine N-oxide or an oxygen.[4]