Hypoiodous acid, HOI

What we have is a solution of two weak acid, hypochlorous acid (HOC1) and hypoiodous acid (HOI) ... 

Kv is the self-ionization constant for water (Table 3.2) and equation (3.18) reflects the not surprising inverse relation between Ka and Kh. It is only when Ka and Kv for a compound are of different magnitudes that it may be classified as an acid or a base. An example which is difficult to classify is hypoiodous acid (HOI) where K = 2.5 x lO11 mol dm 3 andKh = 3.2 x 10 10 mol dm3. Although Kb has been widely used in the past, it is a quantity which is largely redundant, for Ka (or pKa) may be used to express the strength of bases as well as acids, see Table 3.3. 

All forms of iodine including the elemental iodine, hypoiodous acid (HOI), hypoiodite anion (OI ), free iodide anion (I-), and triiodide anion (I3 ) in water also may be measured by the Leuco crystal violet method. The sample is treated with potassium peroxymonosulfate to oxidize all iodide species in the sample. It then is treated with leukocrystal violet reagent for color development. Interference from free chlorine may be eliminated by addition of an ammonium salt. 

Similarly, the oxidation of iodocyclohexane by DMD under a nitrogen-gas atmosphere leads to the iodohydrin and diol as unexpected products (equation 24). The iodohydrin, formed as the major product, clearly reveals that hypoiodous acid (HOI) is generated in situ, which adds to the liberated cyclohexene. Indeed, when methyl iodide (Mel) is oxidized by DMD at subambient temperature in the presence of cyclohexene, the corresponding iodohydrin is obtained in very good yield The latter method may be utilized for the preparation of allylic alcohols with a vinylic iodo functional group from allenes (equation 25) . ... 

Hypoiodous acid (HOI), generation in dioxirane oxidation, 1158 Hypothiocyanite, from lactoperoxidase, 612... 

The claims are not particularly valid, as, for example, the hydrolysis of elemental iodine to hypoiodous acid (HOI) is, of course, affected by pH. At pH 7.5 approximately 84% of the iodine is available as HOI, whereas at pH 9.0 it rises to approximately 97%. However, this type of biocidal control equipment could prove to be useful for small comfort cooling systems with fairly constant operating conditions, as the chemical handling mechanism is safe and the design is simple. 

A volatile iodine species, neither elemental nor organic, which has been found in steam/air atmospheres, has been identified as hypoiodous acid (HOI) (Cartan et al., 1968). In water-cooled power reactors, any fission products released from fuel will pass into hot alkaline water and thence to a steam-air mixture. These conditions are thought to favour the formation of HOI (Keller et al., 1970), but the evidence is indirect. For example, tests for elemental iodine or iodine with an oxidation state higher than that of HOI gave negative results. 

Voilleque, P.G. Keller, J.H. (1981) Air to vegetation transport of1311 as hypoiodous acid (HOI). Health Physics, 40, 91-4. 

With the exception of iodomethane (CH3I) and neopentyl iodide ((CH3)3CCH2l) all the reactions of 0( P) with the alkyl iodides were found to produce as major product an alkene. An example is shown for 1-iodobutane in Figure 9. Hypoiodous acid (HOI), the probable coproduct in each case, was also identified via its known infrared absorptions at 3620 and 1070 cm (Bames et al., 1992). This compound is, however, very short-lived under the conditions of the experiments and was only visible in the infrared spectrum in the initial stages of the reaction (Figure 10) and could therefore not be quantified. For many of the alkenes calibrated reference spectra were available and the yield of the alkene has been determined. Oxygen atoms also react fairly rapidly with alkenes, therefore, the reaction of O atoms with the alkenes has been taken into consideration when calculating the alkene yields from the O + Rl reactions. The yields and the identity of the alkene for the respective O + RI reactions are listed in Table 1. 

Hypochlorous acid Chlorous acid HOCl HOCIO (HCIO2) Hypobromous acid HOBr Hypoiodous acid HOI ... 

In marine aerosol, iodine exists mainly in the inorganic forms, iodate (I03 ) and iodide (H) (Baker et al., 2001), although recently the presence of soluble organic iodine, formed through the reaction of hypoiodous acid (HOI) and organic matter, has also been identified in aerosol samples collected from air above the Adantic Ocean (Baker, 2005). 

Iodine can adopt a range of oxidation states, and various iodine species exist in an aqueous environment — 1 to -i 5, e.g., —1 (iodide, I ) + 1 (hypoiodous acid, HOI) -i5 (iodate, IO3 ). The oxidation of iodide by reactive oxygen species, such as H2O2, has been studied since the early 1920s. Two of the primary variables that determine the concentration and distribution of iodine species formed during the oxidation of iodide are pH and iodide. The effect of pH is dramatic the effect of iodide is nonlinear in that the rate of formation of Ij or hypoiodous acid (HOI) can increase or decrease as iodide is increased, depending on the precise experimental conditions (Gottardi, 1999). 

HA being a buffer acid such as acetic acid. As discussed by Berliner (1951), the first term is not likely to be caused by a rate-determining attack of hypoiodous acid (HOI), formed in a pre-equilibrium, upon un-ionized phenol, but probably by a reaction between the iodine cation (I ) or hypoiodous acidium ion (lOHJ) upon phenolate ion, followed by a fast proton-release (equations 10-11). 

Asensio and coworkers reported a low temperature oxidation of iodomethane with DMDO to afford a pale yellow precipitate of iodosylmethane (20, Scheme 2.10) [104]. Upon raising the temperature to -40 °C, in the presence of moisture iodosylmethane decomposes to form the unstable hypoiodous acid, HOI, which can be trapped in situ by an alkene to afford iodohydrins. The formation of MelO has also been detected in the photochemical reaction of iodomethane with ozone in an argon matrix at 17 K [105], A similar low-temperature reaction of trilluoroiodomethane affords the unstable CF3IO, which was identified by infrared spectroscopy [106]. 

A second iodide ion then attacks the hypoiodous acid (HOI, a weak acid with a of about 11) produced, yielding molecular iodine ... 

At neutral pH, oxidation is insignificant in the absence of heat, light, and metal ions. Above pH 11, iodine disproportionates to hypoiodous acid (HOI), iodate (10 J), and iodide. 

The disproportionation of hypoiodous acid HOI has also been often studied ... 

Considerably larger uncertainties have to be noted regarding the specific partition coefficient of hypoiodous acid HOI in this respect, several contradictory mea-... 

In addition, hypoiodous acid HOI can be formed by radiolytic oxidation of iodide in aqueous solution saturated with nitrous oxide or by radiolytic reduction of iodate in hydrogen-saturated aqueous solution (Fletcher and Miller, 1985). 

Hypochlorous Acid (HOCl), Hypohromous Acid (HOBr), Hypoiodous Acid (HOI)... 

Hypochlorous acid HOCl, hypobromous acid HOBr, and hypoiodous acid HOI are formed in the chain termination reactirais between CIO, BrO, lO radicals and HO2 radicals. Since they have absorption spectra in the ultraviolet to visible regirai, the photolytic regeneration of the radicals has to be considered in the atmosphere. 

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