The Autoxidation of Stannous and Cuprous Chlorides by Air

Abstract

The oxidation of solutions of stannous chloride was first studied extensively by Young1 who found that the reaction was somewhat dependent upon the acidity of the solution, highly sensitive to the action of certain catalysts such as copper and iron salts, and further, was inhibited by some of the alkaloids and certain other substances. The reaction was also studied by Miyamoto,2 who determined the effect of acid concentration, the rate of bubbling of the oxygen, and several other factors.It has been shown by many investigators that autoxidations are catalyzed by the presence of certain metallic ions, notably by those of copper, iron, manganese, cobalt, and nickel. This investigation was originally undertaken with the object of finding out whether or not a mixture of these ions exhibit promoter action in the case of autoxidations. Since no cases of promoter action were found, certain physical and chemical conditions affecting the autoxidation of stannous and cuprous chlorides have been studied.Reagents: In most cases no special precautions were taken to further purify the reagents inasmuch as very pure reagents were available. The stock solutions of stannous chloride were made by dissolving a weighed amount of the salt in air-free distilled water containing enough hydrochloric acid to prevent the precipitation of any of the basic chlorides of tin. These solutions were kept under an atmosphere of hydrogen.Apparatus: The apparatus used in these experiments was essentially the same as that used by Walton.3 This apparatus consists of a burette and leveling tube connected to a reaction flask by means of capillary glass tubing. The reaction flask was clamped in a vertical position and by means of an appropriate mechanism, it was rotated back and forth around the vertical axis.The only deviation from the original apparatus was in the shape of the reaction flask (Fig. i). The bottom of a 150 cc. round bottom Pyrex flask was heated in such a way that a narrow band, extending to within an inch of the end of the neck on either side and parallel to the vertical axis, was softened. This softened portion was then pressed in by the edge of an iron spatula so that a fissure about one-half inch deep was formed. A second fissure was made in a plane at right angles to the first. When shaken, the ridge on the inside of the flask breaks the surface of the liquid and in this way drives the liquid into the gaseous phase and drives the gas into the liquid phase.Method of Procedure: The concentration of acid in the stannous chloride solution was determined by titration of a measured sample with standard

Copper(i)-mediated synthesis of β-hydroxysulfones from styrenes and sulfonylhydrazides: an electrochemical mechanistic study

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Cu-doped zeolitic imidazolate framework catalysed highly selective conversion of alkynes to $$\upbeta $$ β -keto and vinyl sulfones using sodium sulfinates

“…A plausible reaction mechanism for oxysulfonylation and hydrosulfonylation from these results and relevant literature [29][30][31][32][33][34][35][36][37][38] is illustrated in Scheme 2. In the first step, sodium p-toluene sulfinate is oxidized in the presence of Cu(II) catalyst and sulfonyl radical A is generated, which reacts with an alkyne to give a radical intermediate B.…”

Influence of current density on oxygen transfer in an electroflotation cell

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