Dependence of the solubility of atmospheric oxygen in weakly alkaline aqueous solutions on surfactant concentration

Oxidation of polysorbates – An underestimated degradation pathway?

“…Striving for clarifications on how iron and stainless-steel exposure lead to polysorbate degradation, Kranz et al (2020) proposed a working hypothese where oxidation mainly takes place within micelles ( Kranz et al, 2020 ). They argued that micelles possess a higher oxidation potential due to following reasons: (i) higher solubility of molecular oxygen in the apolar environment demonstrated for non-ionic surfactants at pH 8.0 ( Chistyakova et al, 2012 ), (ii) complexion of metal ions by POE moieties ( Sari et al, 2006 ), or (iii) attractive interactions between the micelle-dissolved negatively-charged fatty acids and the positively-charged iron ions ( Kranz et al, 2020 ). In this context, micelles are claimed to act as "tiny" reaction vessels, as no oxidation markers for PS20 and PS80 were detected after dissolving micelles by t-BuOH.…”

Effect of Bulk Nanobubbles on the Flocculation and Filtration Characteristics of Kaolin Using Cationic Polyacrylamide

“…The experimental results showed that with an increase in the treatment time of ultrasonic and hydrodynamic cavitation, the viscosity of flocculants decreases gradually and a flocculant mixture system with multimolecular weight is formed. These modified flocculants have been shown to create smaller and tighter flocs, reducing total dewatering resistance, and increasing filter cake porosity [22,31,32].…”

Vanadium Catalyst in Micelles: Toward a Greener Aerobic Oxidative Cleavage of Vicinal Diols in Water

“…As far as oxidation reactions in micellar media are concerned, most reported protocols use either stoichiometric amounts of transition metals − or primary oxidants such as hydrogen peroxide (H 2 O 2 ), tert -butyl hydroperoxide (TBHP), , or sodium hypochlorite (NaOCl) to run reactions such as the oxidation of alkenes, − phenols, or organosulfur compounds − and Baeyer–Villiger oxidations. , Aerobic oxidations have interestingly enough not been the object of many studies, despite the fact that air and O 2 are cheap and clean oxidants and exhibit high solubility inside the hydrophobic core of micelles, thus increasing local oxygen concentration. − Reported aerobic reactions are the Cu/TEMPO-catalyzed oxidation of benzylic and allylic alcohols, − the oxosulfonylation of aryl alkynes under acidic conditions, and the NaI-catalyzed oxidative sulfonylation of ketones. Gold nanoclusters trapped in the PEG chains of non-ionic cross-linked micelles have also been used to oxidize α-hydroxy ketones under oxygen to form the corresponding bis-ketone product …”