Permanganate oxidations in non-aqueous solvents. I. Oxidation by triphenylmethylarsonium permanganate

Abstract

Quaternary arsonium cations have been widely used in analysis,l mainly in the formation, with anionic complexes, of ion-association compounds which are soluble in aprotic solvents.2The triphenylmethylarsonium cation has been used to form ion-association compounds with anionic complexes of a number of metals3-' and has also been used to form ion-association compounds with the ~ermanganate,~ dichromate,g and triiodidelo ions.The tetraphenyIarsonium cation has been used to extract the permanganate ion into non-aqueous solvents.llJ2The permanganate ion can be extracted into non-polar solvents from acid aqueous solutions containing tributylphosphate.The triphenylarsine oxide permanganic acid adduct is soluble in chloroform and nitrobenzene.13Triphenylmethplarsonium permanganate has been isolateds and is soluble in aprotic polar solvents.It is very soluble in chloroform and nitrobenzene (saturated solutions are approximately l~ and 0 .8 ~ respectively) and is sufficiently stable in these solvents to make possible a study of oxidizing properties of the permanganate ion in non-aqueous media.While triphenylmethylarsonium dichromate has no oxidizing properties in nonaqueous solvents,ls the corresponding permanganate behaves like permanganate ion in neutral solution, being reduced in the presence of a suitable reductant to insoluble manganese dioxide.Preliminary investigation of the oxidizing properties of the permanganate ion in chloroform showed that propan-2-01 was oxidized quantitatively to acetone.The results of a typical reaction are shown in Table 1.Kinetics of this reaction and the oxidizing properties with regard to other functional groups will be reported later.