- Photooxidation of Arylazo-Naphtholes with Singlet Oxygen
-
The reaction of p-substituted 4-arylazo-1-naphtholes 1 and 1-arylazo-2-naphtholes 5 with singlet oxygen (produced by methylene blue-sensitized photolysis) has been studied spectroscopically in methanol as a solvent.The rate constants of dye bleaching are the same, irrespective whether the extinctions of the azo or the hydrazone forms of the tautomeric systems are measured.Both reaction series 1 and 5 afford linear Hammett plots, which is discussed in the light of the azo-hydrazone equilibrium of the dyes and an "ene" mechanism of the reaction with singlet oxygen.It could be shown by short-time spectroscopy that the azo-hydrazone isomerization proceeds much faster than the attack of singlet oxygen on the hydrazone form, which explains all observed facts.
- Becker, H. G. O.,Franze, J.
-
p. 957 - 964
(2007/10/02)
-
- SALT EFFECT IN HYDROLYSIS OF 3-ACYL-1,3-DIPHENYLTRIAZENES
-
Rate constants of non-catalyzed hydrolysis of 3-acetyl-1,3-diphenyltriazene (I) and 3-(N-methyl-carbamoyl)-1,3-diphenyltriazene (II) have been measured in the presence of salts (ammonium chloride, potassium chloride, lithium chloride, sodium chloride and bromide, ammonium sulphate, potassium sulphate, lithium sulphate, sodium sulphate, and zinc sulphate) within broad concentration ranges.Temperature dependence of the hydrolysis of the substrates studied has been measured in the presence of lithium sulphate within temperature range 20 deg to 55 deg C.The results obtained have been interpreted by mechanisms of hydrolysis of the studied substances.
- Ludwig, Miroslav,Pytela, Oldrich,Vecera, Miroslav
-
p. 3104 - 3109
(2007/10/02)
-