Recherches sur la formation et la transformation des esters LXXVII [1]. Etude à l'aide de H 2 [ 18 O] de la scission de quelques monoesters phosphoreux et de l'acide propargyl‐benzènephosphonique

(1) Monopotassium phosphite KH 2 PO 3 heated at 300°C with CO[ 18 O] exchanges one atom of oxygen after 3 hours, one to two atoms after 6 hours, and its three O atoms after 12 hours; the probable mecanism of this exchange is discussed. When the same treatment is carried out in the presence of o ‐phenylene diamine hydrochloride, the exchange is total (three O) after 3 hours at 300°C. Treated by this last procedure, benzenephosphonic acid C 6 H 5 PO(OH) 2 undergoes equally a total exchange of its O atoms in 3 hours.