Peroxymonosulfate reaction

Montgomery RE. Catalysis of peroxymonosulfate reactions by ketones. J Am Chem Soc 1974 96 7820-1. 

Bromide ndIodide. The spectrophotometric determination of trace bromide concentration is based on the bromide catalysis of iodine oxidation to iodate by permanganate in acidic solution. Iodide can also be measured spectrophotometricaHy by selective oxidation to iodine by potassium peroxymonosulfate (KHSO ). The iodine reacts with colorless leucocrystal violet to produce the highly colored leucocrystal violet dye. Greater than 200 mg/L of chloride interferes with the color development. Trace concentrations of iodide are determined by its abiUty to cataly2e ceric ion reduction by arsenous acid. The reduction reaction is stopped at a specific time by the addition of ferrous ammonium sulfate. The ferrous ion is oxidi2ed to ferric ion, which then reacts with thiocyanate to produce a deep red complex. 

Oxidation of Chlorides. Hypochlorite can also be formed by the in situ oxidation of chloride ions by potassium peroxymonosulfate [25482-78-4] (36). Ketones like acetone cataly2e the reaction (37). The triple salt of potassium peroxymonosulfate is a stable powder that has been combiaed with chloride salts and sold as toilet bowl cleaners. Bromides can be used ia place of chlorides to form hypobromites, and such combiaations are used to disiafect spas and hot tubs. 

Epoxidation by Dioxirane Derivatives. Another useful epoxidizing agent is dimethyldioxirane (DMDO),86 which is generated by in situ reaction of acetone and peroxymonosulfate in buffered aqueous solution. Distillation gives about aO.lM solution of DMDO in acetone.87... 

Hajipour and coworkers prepared benzyltriphenylphosphonium peroxymonosulfate (BnPhsPHSOs) in a very high yield (95%) and purity (99%). This new oxidizing reagent was applied successfully in various deprotection reactions such as the conversion of oximes, phenylhydrazones, 2,4-dinitrophenylhydrazones and semicarbazones to the corresponding carbonyl compounds in the presence of bismuth chloride under nonaqueous conditions . Oxidative deprotection of trimethylsilyl ethers, tetrahydropyranyl ethers and ethylene acetals with BnPh3PHS05 under microwave irradiation affords the corresponding carbonyl compounds in very high yields (equation 71). The same reaction also proceeds under nonaqueous conditions ". 

Sulfides in the electrophilic positions are often oxidized to sulfones to facilitate nucleophilic displacement reactions. The sulfoxide is initially formed, and can sometimes be isolated, but normally the oxidation is allowed to proceed fully to give the sulfone. Peroxyacids are commonly used as the oxidant, although other reagents such as oxone (potassium peroxymonosulfate) can also be employed <20030L1011, 2006ARK(vii)452>. 

Trimethoxybenzaldehyde lc (0.196 g, 1.0 mmol), hydroxylamine hydrochloride (0.077 g, 1.1 mmol) and peroxymonosulfate (0.61 g, 1.0 mmol) doped on a neutral alumina (1.0 g) were mixed thoroughly on a vortex mixer. The reaction mixture was placed in an alumina bath inside a commercial microwave oven (operating at 2450 MHz frequency) and irradiated for a period of 7 min. After completion of the reaction (monitored by TLC) the inorganic support was separated by filtration, after eluting the product with dichloromethane (2x 15 mL). The solvent was removed and the residue on purification by column chromatography on silica gel gave the corresponding trimethoxybenzonitrile 2a in 95% yield and there was no evidence for the formation of any side products. 

Aminolysis of phenyl dithioacetates,8 pyridinolysis of O-ethyl dithiocarbonates,9 reaction of pyrrolidine with O-ethyl 5-aryl dithiocarbonates,10 aminolysis of chlorothionformates,11 pyridinolysis of alkyl aryl thioncarbonates,12 reaction of anionic nucleophiles with nitrophenyl benzoate and its sulfur analogues,36 hydrolysis of methyl benzoate and phenyl acetate containing SMe, SOMe and S02Me substituents,42 solvolysis of phenyl chlorothioformate,79 synthesis of new thiadiazoles,124 examination of a neighbouring sulfonium group in ester hydrolysis,136 hydrolysis of V-type nerve agents,250 and the reactions of peroxymonosulfate ion with phosphorus(V) esters have all been looked at previously in this review. 

It has been apparent for some time that the inhibition of sulfite autoxidation by organic compounds is due to their reactions with free radical intermediates. Further, it seems likely that the chemical effects associated with S02 autoxidation are due to these radicals or, possibly, peroxymonosulfate. Now that the reactivities of the likely free radical intermediates are known, the mechanism of these effects can be begun to be understood. For many organic compounds, like hydroquinone and other phenolic species, reaction with S03 and SO " is possible. Indeed, they prove to be the most efficient inhibitors of S02 autoxidation and the order of... 

Deister and Warneck [129] reported a rate constant for reaction 82 of k = 5.5 x 108 M 1 s-1 while the branching ratio ksiAso = 0-41. The thermal oxidation step (reaction 83) involves reaction of peroxymonosulfate, SOs2-, with sulfite at pH 7-8, = 350M-1s-1. The catalytic propagation cycle, which... 

The three-membered peroxide systems produced from ketones in the presence of peroxymonosulfate have been discussed separately above because of their importance. There is, however, another three-membered ring peroxide which needs noting the reaction of alkoxysulfuranes with anhydrous hydrogen peroxide. Such systems have been employed for the low temperature epoxidation of alkenes (Figure 2.50).156... 

In addition to the S(IV) —H202 reaction, the reactions of other peroxides such as peroxymonosulfate, peroxyacetic acid, and methyl hydroperoxide with S(IV) are also sensitive to specific-acid catalysis (Hoffmann and Calvert, 1985). The rate of oxidation of S(IV) by HSO / is comparable to the rate of oxidation of S( IV) by hydrogen peroxide (Betterton and Hoffmann, 1988). We have proposed a general mechanism for the ROOH-S(IV) reaction in which the rate-determining step involves the acid-catalyzed decomposition of a peroxide-bisulfite intermediate. The rate expression applicable for this mechanism is... 

Although peroxymonosulfate is potentially highly reactive from a thermodynamic point of view, there may be a kinetic barrier for reaction with HS03. This, I in turn, suggests that under certain conditions in tropospheric water droplets i where S(IV) is the dominant reductant the concentration of HSOj may build up [ to unexpectedly high levels. 

Halogens can also be generated in situ by the action of an oxidizing agent on a sodium halide.226 In this example (3.16), the oxidizing agent is potassium peroxymonosulfate (Oxone). The reactions were run in water diluted with acetone, ethyl acetate or carbon tetrachloride. Bromine can... 

Dioxiranes are good selective oxidants. Some /3-diketones have been oxidized to alcohols (4.56) in 95% or higher yield.269 The dioxiranes are made and used in solution. The nickel catalyst speeds up reaction 4.56. Hydrocarbons can be functionalized (4.57) in up to 92% yield in this way.270 A dioxirane phase-transfer catalyst, produced in situ with potassium peroxymonosulfate, has been used epoxidize an olefin to an epoxide (4.58) in up to 92% yield.271... 

Potassium peroxymonosulfate has been used in the Nef reaction to convert 1-nitrohexane to caproic acid in 98% yield.275 Replacement of the potassium ion by tetrabuty-lammonium ion allows the oxidant to be used in acetonitrile and methylene chloride. (Less toxic solvents would be desirable.) When this reagent was used with a manganese catalyst, 1-octene was epoxidized in more than 99% yield.276 It also converted ethylbenzene to acetophenone with more than 99% selectivity. 

---