Sodium sulphite, oxidation

Sodium arsenite does not oxidize in air while sodium sulphite oxidizes. When mixture of sodium arsenite and sodium sulphite is treated, both of them undergo simultaneous oxidation. Oxidation of sodium sulphite catalyses the oxidation of sodium arsenite. 

Physical (including thermochemical and explosive) properties Chemical properties of 2,4,6-trinitrotoluene Reaction with sodium sulphite Oxidation of 2,4,6-trinitrotoluene Reduction of 2,4,6-trinitrotoluene Melhylation of 2,4,6-trinitrotoluene... 

Copperil) oxide, CujO, occurs naturally as the red cuprite. It is obtained as an orange-yellow precipitate by the reduction of a copper(II) salt in alkaline solution by a mild reducing agent, for example glucose, hydroxylamine or sodium sulphite ... 

This direct sulphonation should be compared with the indirect methods for the preparation of aliphatic sulphonic acids, e.g., oxidation of a thiol (RSH -> RSOjH), and interaction of an alkyl halide with sodium sulphite to give the sodium sulphonate (RBr + Na,SO, -> RSO,Na + NaBr). 

Oxidation to acids. Varm together in a small conical flask on a water-bath for lo minutes a mixture of 0 5 ml. of benzaldehyde or salicylaldehyde, 15 ml. of saturated KMn04 solution, and 0-5 g. of NajCOj. Then acidify with cone. HCl, and add 25% sodium sulphite solution until the precipitated manganese dioxide has redissolved. On cooling, benzoic or salicylic acid crystallises out. 

The elements present in a host of pharmaceutical substances are determined quantitatively by atomic absorption spectroscopy, for example Pd in carbenicillin sodium Cu, Pb and Zn in activated charcoal Fe in ascorbic acid Ag in cisplatin Ph and Zn in copper sulphate Zn in glucogen Zn in insulin Pb in oxprenolol hydrochloride Ni in prazosin hydrochloride Zn in sodium sulphite heptahydrate, and Cd and Pb in zinc oxide. 

Nonen-2-one. J. Gen. Chem. (USSR), Vol. 33, p. 134 of the English translation. Oxidation of the ketone is accomplished in this manner 0.5 mole of n-hexylideneacetone (this should be freshly distilled at 93-95° with 16 mm of vacuo) is shaken in an oxygen atmosphere at 30° for 8 hours. Decompose the hydroperoxides with a little sodium sulphite. Fractionally distill in three steps about 40° at 16 mm vacuo, 93-95° at 16 mm vacuo, and the product is obtained by reducing the vacuum to 1 mm and raising the temp to 107-108°. Yield of pale, yellow, viscous liquid, 6 g. The unreacted starting material (93-95° 16 mm) is used over and over until reacted. 

Nitrososulphonic Acid or Nitrosohydroxylamine-sulphonic Acid, N(NO)(OH)SOgH or H02N2S03H.—The sodium salt of this acid has been prepared by the action of nitric oxide on a caustic soda solution of sodium sulphite 3... 

Bleaching. It is often necessary in the manufacture of lacquer nitrocellulose to remove all traces of coloured substances by bleaching. One method consists in oxidizing with potassium permanganate in the proportion of 1 kg KMn04 to 100 kg of lacquer nitrocellulose in the presence of a little sulphuric acid. After the reaction is over the nitrocellulose is rinsed with water, and the brown colour of manganese dioxide is removed by the action of sulphur dioxide or sodium sulphite. 

The most direct evidence that negative catalysis sometimes works in this way in ordinary thermal reactions, and, therefore, incidentally that the chain mechanism can operate in such reactions, has been found by Backstrom. In the photochemical oxidation of benzaldehyde, heptalde-hyde, and of solutions of sodium sulphite, there are very large numbers of molecules transformed for each quantum of light absorbed, amounting respectively to 10,000,15,000, and 50,000 for the three reactions. Such deviations from Einstein s law show that the light probably sets up chain reactions. These photochemical changes are markedly subject to the action of inhibitors, which presumably cut short the chains. Backstrom establishes the important... 

The results obtained for the oxidation of sodium sulphite solutions containing various alcohols as inhibitors are particularly instructive. The rate of reaction depends upon the concentration of the inhibitor, C, in the following way. 

In some cases, however, the modus operandi is modified. In the oxidation of hydriodic acid with chromic acid, the data indicate that while liberation of iodine takes place, the vanadous or hypovanadic salt employed as the catalyst also undergoes oxidation to vanadate.2 The vanadium compound here belongs to the class of catalysts known as inductors, and the reaction is comparable to the oxidation in aqueous solution of sodium sulphite with sodium arsenite, whereby both sodium sulphate and sodium arsenate are produced. 

Total thiamine Milk Enzymatic hydrolysis of protein with trypsin and thiamine phosphates to thiamine with claradiastase oxidation of thiamine to thiochrome using ferricyanide (derivatization stopped with sodium sulphite) thiochrome extracted with 1-butanol Analytical Nucleosil Phenyl (150 mm, 5 fi Macherey-Nagel). Isocratic methanol + acetonitrile + isobutanol + water (80 +10+10+5 v/v/v/v). 0.7 ml/min. Fluorescence 375/430 nm (ex/em). External standardization. 76 Recoveries 95% thiamine as thiochrome from milk. 

N. R. Dhar observed that the oxidation of sodium sulphite by air is hastened by the simultaneous oxidation of sodium nitrite as a secondary reaction but W. P. Jorissen and 0. van den Pol found that sodium sulphite does not induce the oxidation of sodium nitrite by air or oxygen under ordinary conditions. 

In section6.3.1, it was shown that for the second oxidation wave of sodium dithionite (sulphite oxidation to sulphate), an influence of electron-transfer rate (kinetics) is observed that cannot be neglected. Therefore, first the oxidation of sulphite is studied and described, followed by the oxidation reaction of sodium dithionite. 

In the further scans, this first wave is not observed because in the aforementioned potential region, the electrode surface is no longer a pure platinum one but is a rearranged platinum hydroxide surface39. The results described in section 6.2 showed that the limiting-current plateau of the second oxidation wave (first scan) is controlled by transport of dithionite. This indicates that electron transfer from dithionite to PtOH and/or PtO is a much faster process than transport of dithionite towards the electrode. This is confirmed by the fact that in the further scans an identical limiting-current is obtained. The third oxidation wave in the first scan (second wave for the other scans) is attributed to the oxidation of sulphite described earlier. It is formed as a reaction product of the sodium dithionite oxidation and also of the homogeneous decomposition of sodium dithionite. Also in this case, a hysteresis effect is observed for the sulphite forward/back-ward sweep oxidation wave. 

In a buffer of pH=8, completely different results were obtained for sulphur dioxide and sodium sulphite as starting species. Starting from sulphite, only one oxidation wave is obtained around 0.7 V vs. AglAgCl. From Table 12.1 it can be seen that sulphite itself is the main compound in solution, therefore it is clear that this wave can be attributed to Equation 12.17. Its slope (Fig. 12.10, curve 6), obtained by plotting the peak current versus concentration, is situated in the range that allows exchange of two electrons ... 

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