Chlorine dioxide hydrolysis

In solution, chlorine dioxide decomposes very slowly at ambient temperatures in the dark. The primary decomposition process is hydrolysis of chlorine dioxide into chlorite and chlorate ions. The hydrolysis rate is a function of the concentration of hydroxyl ions and temperature, proceeding rapidly at solution pH values above 10 ... 

The reaction chemistry changes when the initial reactant concentrations are low or there is excess hypochlorous acid present. The [CI2O2] intermediate disproportionation route to chlorine dioxide becomes less important (eq. 48), and the route to chlorite formation by hydrolysis predominates as does the reaction with any available excess HOCl to form chlorate and chlorine ... 

Oxidation of triazine herbicides with chlorine and chlorine dioxide has been widely studied [105-108]. In the case of sulfur-containing triazines, oxidation occurs mainly via cleavage of the weakened R-S-CH3 bond rather than by addition of chlorine. Reactions of S-triazines with chlorine are faster than with chlorine dioxide, and form sulfoxide, sulfone, and a sulfone hydrolysis product. Chlorination with chlorine dioxide only produced sulfoxide [108]. Lopez et al. identified the formation of sulfonate esters during the chlorination of ametryn and terbutryn [106, 107]. Triazine DBFs identified by Brix et al. exhibited higher toxicities than the parent compounds [105]. Similar to triazines, clethodim, a cyclohexanedione herbicide, is oxidized by hypochlorite and chloramines to clethodim sulfoxide and then to sulfone [109]. 

The injury caused by chlorine trifluoride is in part attributed to its hydrolysis products, including chlorine, hydrogen fluoride, and chlorine dioxide. Effects in humans have not been reported but may be expected to be very severe inhalation may cause pulmonary edema, and contact with eyes or skin may cause severe burns. 

The reactivity of acidified chlorite solutions is reduced for bleaching some textiles by adding compounds like polyamines, pyrophosphates, and hydrogen peroxide that suppress the formation of chlorine dioxide (57). Another method is to buffer the solution at pH 5—6 to reduce the rate of chlorine dioxide formation. Hydrolysis of anhydrides and esters or oxidation of alcohols can be used to slowly generate acids to promote chlorine dioxide formation (58). Aldehydes also promote chlorine dioxide generation from neutral chlorite solutions, but the effect is greater than simply lowering the pH as they... 

In the second stage of production the chlorine dioxide is converted into chlorite. This conversion can be carried out by hydrolysis in an alkaline solution, according to the equation ... 

Hydrolysis of CIO3 and C1207 gases also results in perchlorate formation. Chlorine dioxide can be oxidised by ozone with the formation of Cl206. Hydrolysis results in the formation of perchloric acid [(7.41) and (7.40)]. 

Although, under neutral and alkaline conditions, cellulose, methyl p-gluco-pyranoside and methyl p-eellobioside react with chlorine predominantly via formation of hypoehlorites (see Seetion 6.6.1.1), in acid (pH <2), when radical reactions are suppressed by addition of chlorine dioxide, the products are exclusively glueono-5-lactone (and some cellobionolactone from the cello-bioside), in aeeord with hydride abstraction followed by hydrolysis (Figure 6.60)." ... 

To evaluate the overall oxidation reaction of parathion, the kinetics of chemical hydrolysis of parathion and paraoxon first had to be investigated. Then the kinetics of chemical oxidation of p-nitrophenol, paraoxon, and parathion were studied with KMn04. This oxidant was chosen partially because of its accepted use to reduce tastes and odors caused by organic compounds 31, 32, 33, 34) potassium permanganate also is easily applied, and its reduction products are filtered from the finished water. Chlorine and chlorine dioxide were tested for their efiiciencies in oxidizing parathion and paraoxon. 

Taube and Dodgen (217) did not observe any difference in the rate of decomposition of chlorous acid for two solutions with widely different concentrations of chlorate ion. Hong (99) found that chlorate had only a very small, but noticeable, effect on the rate of formation of chlorine dioxide from a chlorous acid solution. At (4-6) x 10 M chlorate ion concentrations, it has been obsejrved (120) that chlorate ion has at most only a very small effect on the rate of disproportionation of chlorous acid. This evidence indicates that the reaction between chlorous acid and chloric acid must be very slow. This hypothesis is consistent with the slow rate of hydrolysis of chlorine dioxide... 

This was reacted with chlorine to give the dichloropregnene compound, then with selenium dioxide to give the dichloropregnadiene compound. By hydrolysis with methanolic potassium hydroxide there was obtained the free 6a-fluoro-9a,11/3-dichloro-A -pregnadiene-16a,-17a,21-triol-3,20-dione. By treatment with acetone in the presence of perchloric acid, the 16,17-acetonide of 6a-fluoro-9a,11/3-dichloro-A -pregnadiene 16a,17a,21-triol-3,20-dione was formed. 

Chemical/Physical. Diuron decomposes at 180 to 190 °C releasing dimethylamine and 3,4-dichlorophenyl isocyanate. Dimethylamine and 3,4-dichloroaniline are produced when hydrolyzed or when acids or bases are added at elevated temperatures (Sittig, 1985). The hydrolysis half-life of diuron in a 0.5 N NaOH solution at 20 °C is 150 d (El-Dib and Aly, 1976). When diuron was pyrolyzed in a helium atmosphere between 400 and 1,000 °C, the following products were identified dimethylamine, chlorobenzene, 1,2-dichlorobenzene, benzonitrile, a trichlorobenzene, aniline, 4-chloroaniline, 3,4-dichlorophenyl isocyanate, bis(l,3-(3,4-dichlorophenyl)urea), 3,4-dichloroaniline, and monuron [3-(4-chlorophenyl)-l,l-dimethylurea] (Gomez et al., 1982). Products reported from the combustion of diuron at 900 °C include carbon monoxide, carbon dioxide, chlorine, nitrogen oxides, and HCl (Kennedy et al., 1972a). 

The compound is produced by evaporating hydrochloric acid solutions of polonium (IV) 6, 26, 74), by heating the dioxide in carbon tetrachloride vapor 74), in hydrogen chloride, thionyl chloride or with phosphorus pentachloride 6) and by heating the metal in dry chlorine at 200°C (6, 25, 74). It is hygroscopic and hydrolyzes in moist air to a white solid, possibly a basic chloride (7)). The tetrachloride is soluble in thionyl chloride and in water with hydrolysis, and is moderately soluble in ethanol, acetone, and... 

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