Tetrapropylammonium perruthenate (TPAP or TPAPR) is the chemical compound described by the formula N(C3H7)4RuO4.

[3] It can also be used to oxidize primary alcohols all the way to the carboxylic acid with a higher catalyst loading, larger amount of the cooxidant, and addition of two equivalents of water.

In this situation, the aldehyde reacts with water to form the geminal diol hydrate, which is then oxidized again.

[4] The oxidation generates water that can be removed by adding molecular sieves.

The catalytic cycle is maintained by adding a stoichiometric amount of a co-oxidant such as N-methylmorpholine N-oxide[5] or molecular oxygen.