Transformation of Phenolic Compounds by Fe(III) in the Aqueous Solution in Dark and Under Irradiation

Abstract

The degradation of phenolic compounds (PC) by Fe(III) aquacomplexes was investigated in homogeneous phase at neutral pH in dark and using monochromatic irradiation lamp (365 nm). The process of degradation depends essentially on the concentration of monomeric species, which is the most reactive species in terms of HO• radicals formation. A dark study of a system containing a mixture of phenolic compounds (3,5-dimethylphenol, 2,6-dimethylphenol, m-methylphenol, phenol) and Fe(III) was performed before starting the photochemical study. In this step only the 2,6-dimethylphenol give a thermal reaction with iron in homogenous solution. Under monochromatic excitation (365 nm), the photodegradation of PC induced by Fe(III) aquacomplexes showed that this process followed pseudo first-order kinetic. We investigate also the effect of initial concentrations of Fe(OH)2+, Fe(III) and the substrate. Tertiobutanol, used as scavenger of (HO•), confirmed that this radical was the main pathway of PC degradation. However the degradation of the 2,6-dimethylphenol in the presence of tertiobutanol, was not slowed completely which confirm that the degradation was a combination of thermal and photochemical reactions.

Meso-functionalization of calix[4]arene with 1,3,7-triazapyrene in the design of novel fluorophores with the dual target detection of Al3+ and Fe3+ cations

“…The latter phenomenon could be accounted for the oxidation of phenolic fragments of calix [4]arenes into the corresponding quinones by action of Fe 3+ ions. 26 To evaluate the changes in emission intensities for the obtained compounds in the presence of various metals cations quantitatively, the uorescence enhancement factors (FEF ¼ I/I o ) have been calculated according to the typical procedure (Fig. 4).…”

“…The latter phenomenon could be accounted for the oxidation of phenolic fragments of calix[4]arenes into the corresponding quinones by action of Fe 3+ ions. 26 …”

“…5 M solution in hexane),2,, iodocyclohexane were purchased and used as received. 5,11,17,26,27, arene (2a), 25,26,27,28-tetramethoxycalix[4]arene (2b), 20 1,3,7triazapyrene (3) 31 were prepared according to the literature procedures.…”

“…2- (1,3,11,17,26,27, 5; 154.8; 154.0; 150.8; 150.5; 148.9; 148.8; 147.1; 136.1; 134.6; 134.5; 134.2; 133.9; 131.6; 129.2; 128.2; 126.6; 126.5; 126.2; 126.1; 122.7; 121.9; 115.5; 65.9; 64.8; 34.5; 34.2; 31.1; 31.05; 30.3; 29.9 ppm. IR (DRA): n 2954, 2866,1628,1555,1478,1388,1359,1244,1201,1117,1019,919,870,798,727,645,578 3,26,27, arene (4b). White solid.…”

“…IR (DRA): n 3888, 3749,3643,3542,3426,3281,2951,1735,1629,1594,1480,1390,1359,1295,1198,987,872,815,704,589 7.22;N,4.93;O,7.51. Found: C,80.32;H,7.58;N,3,26,27, arene (5b). Yellow solid.…”