Di:alkyl phosphate prodn. from phosphite - by oxidn. with nitrous gas with addn. of halogen or inorganic halide to prevent mono:alkyl phosphite formation

摘要

The oxidn. of dialkyl phosphites (I) to dialkyl phosphates (II) with nitrous gas (III) is carried out in the presence of a halogen (IVA) or inorganic halide(IVB). (II) are used in the extn. of metal salts (e.g. of Zn, U or Ni) from aq. solns. in the presence of Fe (III) ions, The (II) obtd. is free from monoalkyl phosphites (V) and only readily available chemicals are needed. Pref. after oxidn. (II) is washed with water. (IV) is pref. X2 or a soluble halide, esp. HX, PX3 or POX3 (in which X is halogen, pref. Cl). The amt. used is pref. 0.01-5 (esp. 0.1-1) wt.% w.r.t. (I). The alkyl gp. of (I) pref. has 1-20 (2-10)C. Oxidn. is pref. carried out at 50-90 deg.C.