Hydrolysis Individual halides

One of the oldest and most popular methods for oxidizing activated halides is the three-step KrShnke oxidation. The individual steps are (i) quatemization of the halide with pyridine (ii) deprotonadon in base and reaction of the resulting pyridinium ylide with AfJV-dimethyl-4-nitrosoaniline and (iii) acid hydrolysis of the nitrone to the carbonyl compound (Scheme S). 

The fusion of individual metal halides and of their mixtures is accompanied, as a rule, by high-temperature hydrolysis (recently, the term, pyro-hydrolysis has been used), which occurs due to the presence of traces of water vapour in the atmosphere over the liquid salts. These traces arise by evaporation of water from hygroscopic salts or are present in the inert gas, which has been insufficiently dried before use. 

Salts. In general, salts are completely ionized in dilute solution of the few exceptions, the halides of mercury, cadmium, and lead are the most notable. Because salts are completely ionized, they have no biological properties other than those of the individual ions of which they are composed. Thus calcium chloride can have no conceivable physiological effects other than those peculiar to calcium ions and to chloride ions. This simple conception needs modification when a salt is derived from either a weak acid or a weak base, because some of the uncharged species is liberated by hydrolysis (see below), thus adding its own biological effect to those of the constituent ions of the salt. 

---