Residue additives sulphur oxides

Cytochrome c has 4 methionine residues, two of which are covalently linked to the haem moiety One of the other two methionine residues is coordinated to the iron in the axial position The major S 2 p band of the crystalline compound appears at 162.6 eV attributable to the methionine residues. Prolongued irradiation causes an increase of the RSOJ or the sulphate band from 28% to 40% (Table 2). When aqueous cytochrome c is recorded, the amount of oxidised sulphur rises to 63% of the methionine sulphur band. The possible extraneously bound redox active transition metals, probably, have created a metal driven Haber Weiss reaction which led to the marked amount of oxidised sulphur observed. Splitting of the iron-sulphur bonding by cyanide results in dramatic increase of the 167.7 band and the additional appearance of a S 2p signal at 164.3, probably due to RS=0 species. This oxidation is believed to be catalyzed by the haem iron. Hydrogen peroxide alone converts the methionine sulphur completly to sulphonic acid. 

Equal weights of distilled p-phenetidine and glacial acetic acid are heated under a reflux with the addition of a little fused sodium acetate until no free base remains (diazotise and test with alkaline j8-naphthol). The excess acetic acid is removed by distillation in vacuo, and the residue dissolved in boiling water to which animal charcoal is added, and after cooling and filtering, phenacetin separates out. It is filtered, washed, and recrystallised from water or 60% alcohol, a little sulphur dioxide solution being added to prevent oxidation. 

This is the solid residue left when turpentine is distilled for the preparation of oil of turpentine. It consists essentially of resin acids and their oxidation products and forms brittle, translucent masses with a peculiar resinous odour and a colour varying from pale yellow to dark brown D = 1 05-1 085. It is readily soluble in alcohol (1 part in 10 parts of 70% alcohol) and dissolves also in methyl or amyl alcohol, ether, acetone, benzene, chloroform, carbon disulphide or oil of turpentine in petroleum ether it is not completely soluble. It is easily and completely saponified by caustic soda solution. Addition of a drop of concentrated sulphuric add to a solution of a small quantity of colophony in acetic anhydride produces an intense violet-red or purple coloration, soon changing to yellowish-brown. Different types or grades of colophony are sold, distinguished mainly by the colour and origin. 

Fusel oil may be detected by adding water, shaking out with chloroform, separating, and allowing the chloroform to evaporate. The residue wifh addition of dilute sulphuric acid should give no smelt of fusel oil. Fusel oil may he estimated quantitativdy by oxidation to valeric arid. 

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