Search results for "Autocatalysis"
showing 3 items of 13 documents
Über die Autoxydation gesättigter makromolekularer Kohlenwasserstoffe
1973
Die Autoxydation in Losung von isotaktischem Polypropylen bzw. Polyputylen-1 gehorcht einer anderen kinetischen Beziehung als die entsprechende Autoxydation von ataktischem Polypropylen, Polybutylen-1 und Polyathylen. Die Autokatalyse der Autoxydation isotaktischer Produkte wird durch einen bimolekularen Kettenstart der gebildeten Hydroperoxyde hervorgerufen, wahrend bei ataktischen Produkten ein monomolekularer Kettenstart beobachtet wird. Die unterschiedliche Kinetik der Autoxydation kann eindeutig auf Taktizitatsunterschiede zuruckgefuhrt werden. The autoxidation of isotactic polypropylene and poly-butylene-1 in solution shows a kinetic difference from that of atactic fractions of these …
Unexpectedly ambivalent O-2 role in the autocatalytic photooxidation of 2-methoxybenzyl alcohol in water
2015
An unusual autocatalytic photooxidation of 2-methoxybenzyl alcohol has been observed under UV irradiation in aqueous medium. The homogeneous oxidation is catalyzed by the corresponding aldehyde that is also the main oxidation product. The trend of alcohol disappearance rate matches the typical shape of an autocatalytic process, where a crucial and ambivalent role is played by the presence of molecular oxygen. Low oxygen concentrations give rise to a zero-order reaction since the beginning of irradiation, while higher amounts of oxygen reduce the alcohol oxidation rate until the aldehyde reaches a concentration high enough to speed up the alcohol's conversion. Experiments performed by varyin…
Dual application of (aqua)(chlorido)(porphyrinato)chromium(III) as hypersensitive amine-triggered ON switch and for dioxygen activation.
2014
Although synthesis and substitution reactions of chlorido chromium(III) porphyrins Cr(III)(TPP)(Cl)(L) (H2TPP = 5,10,15,20-tetraphenyl porphyrin, L = pyridine, H2O, ROH, etc.), have been well-established in coordination chemistry for decades, an unexpected dichotomous reactivity of Cr(III)(TPP)(Cl)(H2O) (1) toward amines is disclosed here. This reactivity leads to the application of 1 as highly sensitive substoichiometric and irreversible ON switch for amine detection by an autocatalytic pathway. The concomitant activation of O2 by the 1/amine system is furthermore exploited in an electrochemically driven epoxidation of norbonene using O2 as initial oxidant.