Aqueous Persulphate Research Articles

Voltage-controlled spectral shift of porous silicon electroluminescence.

In this paper, it is reported that the electroluminescence (EL) of porous silicon shows a reversible spectral shift as large as 270 nm for an external bias variation of 0.6 V. This electroluminescence is obtained upon cathodic polarization of lightly doped n-type porous silicon in contact with aqueous persulphate solutions. The study of the EL behavior as a function of the external voltage and the persulphate ion concentration proves that while the amplitude of the EL is proportional to the intensity of the exchanged current, the spectral position is only determined by the applied voltage

A dye-sensitized photocatalyst (p-type CuCNS) for the generation of oxygen from aqueous persulphate

p-CuCNS coated with Rhodamine B and then photoplatinized is found to photogenerate oxygen from aqueous persulphate with the dye remaining photostable. The photochemical mechanisms involved are discussed.

Persulphate initiated polymerisation of methacrylamide—I: Kinetics and molecular weight dependences

A kinetic study of the aqueous persulphate initiated polymerisation of methacrylamide has shown that the rate of polymerisation is represented by the equation R p = k [ M] [ I] 1 2 where the overall rate constant, k = 1.3 × 10 9 exp (−18,400/ RT) 1 1 2 mol − 1 2 s −1 . Chain transfer with monomer, where C M = 5.4 × 10 −3 at 60°, is shown to be the dominant transfer step. Comparison with kinetic studies of the analogous acrylamide polymerisation shed doubt on the ‘cage effect’ interpretation of complex orders with respect to monomer. An alternative explanation is proposed.

Polymerization kinetics of tetrafluorethylene in aqueous persulphate solutions

Polymerization kinetics of tetrafluorethylene in aqueous persulphate solutions

Oxidation by persulphate. Part IV. Silver-catalysed oxidation of primary aliphatic amines

Oxidation of a primary aliphatic amine, RCH2·NH2, by aqueous persulphate under alkaline conditions and in the presence of a catalytic amount of silver nitrate, gave the aldimine, RCH:N·CH2R, which was subsequently hydrolysed to the aldehyde, RCHO, and the original amine, or was hydrogenated to the corresponding secondary amine, (RCH2)2NH. The yield of aldehyde varied from 15 to 95% among C3—C9 amines, and the conversion was favoured by branching in the alkyl chain or by the presence of an α-phenyl group. Under similar conditions, a primary amine of the type R1R2CH·NH2 was converted into the ketone, R1R2CO, without separation of the ketimine. Primary amines of the type R1R2R3C·NH2 were unchanged. Secondary reactions may complicate the oxidations.

Oxidation by persulphate. Part V. Silver-catalysed oxidation of secondary aliphatic amines and α-amino-acids

Silver-catalysed oxidation by cold aqueous persulphate, which converts primary aliphatic amines into aldehydes or ketones, gave poorer yields when applied to related secondary amines of the types (RCH2)2NH and (R1R2CH)2NH. α-Amino-acids were converted into aldehydes, but the yields were not better than with other inorganic oxidants.

Colour changes in the uncatalyzed and Ag+ catalyzed oxidation of aromatic amines by persulphate ion

A scheme has been proposed for the identification of some of the aromatic amines, viz., aniline, ethyl and methyl aniline, diethyl and dimethyl aniline, α- and β-naphthylamine, o-, m- and p-toluidine, o-, m- and p-anisidine, m- and p-phenetidine, o-, m- and p-phenylenediamine, carbazole, benzidine, o-tolidine, quinoline and iso-quinoline, p-xylidine and diphenylamine. It is based on the reaction of an aqueous persulphate solution with an alcoholic solution of the amine.