Iodoxy compounds

Diphenyl selenide, 24, 91 Dr- -PROPYLAMINO ETHYL AMINE, 23, 24 y-Di-ra-propylaminopropylamine, 24, 46 Disproportionation, of an iodoso and an iodoxy compound, 22, 52 of iodosobenzene by steam distillation, 22, 72... 

In general the iodonium bases are formed from iodoso- and iodoxy-compounds in the presence of alkali, preferably silver oxide the two organic iodine compounds combine with elimination of iodate. 

The iodoso- and, in particular, the iodoxy-compounds decompose with a puff when heated, since the oxygen which they contain is present in a state of tension. They liberate an equivalent amount of iodine from acidified potassium iodide solution and are thereby reconverted into iodobenzene. 

Iodobenzene [591-50-4], C6HBI, mol wt 204.02, 62.23% I, mp —30°C, bp 188—189°C, is a colodess liquid that rapidly becomes yellow and has a characteristic odor. It is insoluble in water, but completely miscible with alcohol, chloroform, and ether. It has a density of 1.832 g/mL at 20°C and a refractive index of 1.621 at 4°C. Iodobenzene is prepared by the reaction of iodine and benzene in the presence of an oxidizing agent and from benzeneiazonium sulfate and potassium iodide (122). Iodobenzene is used as a heavy liquid for refractive index determinations, but probably its principal use is in the synthesis of iodoso compounds, RIO iodoxy compounds, RI02 and iodonium salts, R IX. 

The following procedure is used in the analysis of iodoso and iodoxy compounds. In a 200-cc. iodine flask are placed 100 cc. of water, 10 cc. of 6 N sulfuric acid, 2 g. of iodate-free potassium iodide, 10 cc. of chloroform, and finally the sample, about 0.25 g. The flask is shaken for fifteen minutes (or longer, if the reaction is not complete), and then the mixture is titrated with 0.1 N sodium thiosulfate. If the sample is pure the change of color in the chloroform layer may be taken as the end point, but if impurities are present starch must be used, for the impurities impart a brownish color to the chloroform. This solvent is desirable, as it facilitates the reaction with potassium iodide by dissolving the reaction products. Iodosobenzene may be differentiated from iodoxybenzene, for the former reduces iodide ion in a saturated sodium borate solution, whereas the latter does not.1 The reactions involved are ... 

The iodoso- and iodoxy-compounds explode when heated. 

AsO(OH)2, is obtained. The iodoxy compound is precipitated by dilute sulphuric acid, and the product filtered, washed, and dried. It crystallises in needles, which explode sharply on heating, and are insoluble in the usual solvents. 

The most important applications of peroxyacetic acid are the epoxi-dation [250, 251, 252, 254, 257, 258] and anti hydroxylation of double bonds [241, 252, the Dakin reaction of aldehydes [259, the Baeyer-Villiger reaction of ketones [148, 254, 258, 260, 261, 262] the oxidation of primary amines to nitroso [iJi] or nitrocompounds [253], of tertiary amines to amine oxides [i58, 263], of sulfides to sulfoxides and sulfones [264, 265], and of iodo compounds to iodoso or iodoxy compounds [266, 267] the degradation of alkynes [268] and diketones [269, 270, 271] to carboxylic acids and the oxidative opening of aromatic rings to aromatic dicarboxylic acids [256, 272, 271, 272,273, 274]. Occasionally, peroxyacetic acid is used for the dehydrogenation [275] and oxidation of aromatic compounds to quinones [249], of alcohols to ketones [276], of aldehyde acetals to carboxylic acids [277], and of lactams to imides [225,255]. The last two reactions are carried out in the presence of manganese salts. The oxidation of alcohols to ketones is catalyzed by chromium trioxide, and the role of peroxyacetic acid is to reoxidize the trivalent chromium [276]. 

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