Sulphuric acid Winkler

An acid of sp. gr. 1-517 at 15°/4° absorbs 0-88 per cent, of nitric oxide so that the coefi. of absorption is 12-5. The speed of absorption varies with the cone, of the acid. C. A. Winkler obtained no absorption of nitric oxide by the hydrate of sulphuric acid and M. Berthelot said that nitric oxide is very slightly soluble in cone, sulphuric acid. O. Lubarsch made some observations on this subject. E. Desbassayns de Richemont said that if the sulphuric acid contains a little ferrous sulphate, nitric oxide imparts to it a red colour and if copper sulphate, a violet colour. In the latter case, W. Manchot found that the coloration is due to the formation of an easily dissociated copper nitrosylsulphate, CuSO4.NO— vide infra. For the corresponding compound with ferrous sulphate, vide infra. G. Lunge found that 1 c.c. of sulphuric acid of sp. gr. 1-84 absorbs 0-035 c.c. of nitric oxide, and an acid of sp. gr. 1-50, 0-017 c.c. and O. F. Tower, v vol. of nitric oxide at 760 mm. absorbed by one vol. of acid 18° and H2S04 per cent. 

Clemens Alexander Winkler (Freiberg, 26 December 1838-Dresden, 8 or 10 October 1904) was (1873) professor in the Mining Academy in Freiberg. Besides discovering germanium he worked out the contact process for sulphuric acid for the Badische Co. (see p. 903). 

Mercaptans are oxidised to disulphides by peroxodisulphate. Eager and Winkler studied the kinetics of the oxidations of n-butyl, n-octyl, and n-dodecyl mercaptans in acetic acid/water solvent (80 ml acid-I-20 ml water) and found first-order kinetics with respect to peroxodisulphate. The first-order rate coefficient increases with increase of mercaptan concentration, and reaches a limit at about 5 x 10 Af mercaptan. A decrease in the first-order rate coefficient with increase of the initial peroxodisulphate concentration was observed and attributed to a salt effect. Eager and Winkler suggested a mechanism involving sulphate radical ions. Levitt proposed a mechanism involving sulphur te-troxide, but there is no evidence for its formation in peroxodisulphate oxidations. 

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