Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The oxidation of hydroxy phosphonates to acyl phosphonates using three heterogeneous systems, MnO 2 , KMnO 4 and CrO 2 was investigated. The best results were obtained with CrO 2 in refluxing acetonitrile. ... The oxidation of hydroxy phosphonates to acyl ...