The oxidation of secondary alcohols by potassium tetraoxoferrate(VI)

Abstract

The kinetics of the oxidation of 2-propanol, 1,1,1-trifluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 1-phenyl-2,2,2-trifluoroethanol, 1-(4-methylphenyl)-2,2,2-trifluoroethanol, 1-(3-bromophenyl)-2,2,2-trifluoroethanol, and 1-(3-nitrophenyl)-2,2,2-trifluoroethanol by potassium tetraoxoferrate(VI) have been studied under basic conditions. The products are ketones, formed in almost quantitative yields, iron(III) hydroxide, and dioxygen. The reactions are characterized by substantial enthalpies of activation (40–60 kJ/mol), very unfavorable entropies of activation, large primary deuterium isotope effects, and a positive Hammett ρ value. Both acid and base catalysis are observed. Acid catalysis is attributed to formation of a more reactive oxidant, HFeO4−, at low pH. Base catalysis is attributed partly to the conversion of the reductants to alkoxide ions at high pH, and partly to the reaction of hydroxide ion with tetraoxoferrate(VI) to give a five-coordinated species, HOFeO43−, that reacts rapidly with nucleophiles. A reaction mechanism involving formation of an intermediate ferrate ester is proposed. Keywords: oxidation, alcohols, potassium tetraoxoferrate(VI), ferrate esters, base catalysis, acid catalysis.

Ferrate(VI) in the Treatment of Wastewaters: A New Generation Green Chemical

“…25-652, [18]) as reference for the pure substance is available. Moreover, it was also proposed that Fe(VI) ions can have three resonance hybrid structures in aqueous solution as shown in figure (4) [21]. Of these three resonance structures in figure 4, the structures of '1' and '2' were suggested as main contributors to the resonance structures of Fe(VI) based on theoretical studies of metal oxide structures.…”

“…The rate constants k 1 , k 1`, k 2 , k 2`, k 11 , k 11`, k 21 and k 21` were obtained by the least-square fitting method. Results obtained were given in Table 7.…”

A study of the preparation and reactivity of potassium ferrate

“…The expected benefits of this combined effect in advanced water and wastewater treatment are higher water quality (particularly a lower risk of producing hazardous chemical byproducts), and lower operational and capital costs. Previous investigations have considered aspects of Fe(VI) treatment such as the inactivation of micro-organisms (Kazama, 1995), its reactivity with a wide range of aqueous contaminants, such as ammonia and heavy metals (Murmann and Robinson, 1974) and the treatment of industrial and municipal wastewaters (Delaude and Laszlo, 1996;Johnson and Read, 1996;Norcross et al, 1997;Read et al, 1998;Sharma et al, 1999). Recently we reported on the degradation of phenol and chlorophenols by potassium ferrate (Graham et al, 2004).…”

An Overview on Production and Applications of Ferrate(VI)

“…Study of ferrate(VI) seems to be essential due to its high capacity for the removal of organic and inorganic compound that are harmful for the environment. Ferrate(VI) in comparison with other current oxidants is a cheap and low-risk one (1). Three methods have been developed to produce ferrate(VI) including (i) electrochemical method, (ii) thermal method, and (iii) chemical method (2,3).…”

“…Three methods have been developed to produce ferrate(VI) including (i) electrochemical method, (ii) thermal method, and (iii) chemical method (2,3). Analytical methods can also be used to express the capacity and structure of ferrate(VI) species (1,4,5). Ferrate(VI) can be used as an oxidizer, coagulant and disinfector in water and wastewater treatment.…”