This manuscript describes our research work devoted to the understanding of the aqueous phase reactions of phosphate and polyphosphate radicals. Inorganic phosphate and polyphosphate radicals were generated after photolysis of peroxo-diphosphate, tripolyphosphate and pyrophosphate ions. The reactions of SO4•-radicals with P2O74- and P3O105- are also discussed.
The logarithm of the bimolecular rate constants for the reactions of the three phosphate radicals (H2PO4• HPO4•- PO4•2-) with substituted benzenes are discussed in terms of Hammett correlations and a reaction mechanism is proposed. Phenoxyl type radical formation from the reactions of H2PO4• and HPO4•- radicals with phenol, chlorobenzene, and α, α, α-trifluorotoluene (TFT) supports the contribution of an addition pathway yielding a phosphate adduct with the substituted benzene. Additional information on the absorption spectra and decay kinetics of the hydroxycyclohexadienyl radicals of chlorobenzene and TFT is also given.
HelzG.R., ZeppR.G., and CrosbyD.G. (eds), Aquatic and Surface Photochemistry, Lewis Publishers, London, 1994.
2.
FaustB.C.Photochemistry of clouds, fogs and aerosols. Environ. Sci. Technol., 1994, 28, 217–222A.
3.
LegriniO., OliverosE., and BraunA.M., Photochemical Processes for water treatment, Chem. Rev., 1993, 93, 671–698.
4.
NetaP.; HuieR.E., and RossA.B.Rate constants for reactions of inorganic radicals in aqueous solution. J. Phys. Chem. Ref. Data, 1988, 17, 1027–1284. And references therein.
5.
BuxtonG.V., GreenstockC.L., HelmanW.P., and RossA.B.Critical review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals in aqueous solution. J. Phys. Chem. Ref. Data, 1988, 17, 513–816. And references therein.
6.
HuberJ.R., and HayonE.Flash-photolysis in the vacuum ultraviolet region of the phosphate anions, H2PO4-, HPO42-, and P2O74- in aqueous solutions. J. Phys. Chem., 1968, 72, 3820–3827.
7.
MaruthamuthuP., and NetaP., Phosphate radicals. Spectra, acid – base equilibria, and reactions with inorganic compounds. J. Phys. Chem., 1978, 82, 710–713.
8.
RossoJ.A., RodríguezNieto F.J., GonzalezM.C., and MártireD.O., Reactions of phosphate radicals with substituted benzenes. J. Photochem. Photobiol. A: Chemistry, 1998, 116, 21–25.
9.
CencioneS.S., GonzalezM.C., and MártireD.O.Reactions of phosphate radicals with substituted benzenes. A structure – reactivity correlation study. J. Chem. Soc., Faraday Trans., 1998, 94, 2933–2937.
10.
RossoJ.A., AlegrettiP.E., MártireD.O., and GonzalezM.C.Reaction of sulfate and phophate radicals with α, α, α – trifluorotoluene. J. Chem. Soc, Perkin Transactions, 2, 1999, 205–210.
11.
CorbridgeD.E.C.in Phosphorus. An outline of its chemistry, biochemistry and technology. Studies in Inorganic Chemistry, 20, 5th edn; Elsevier, New York, 1995.
12.
BaoZ.-C., and BarkerJ.R.Temperature and ionic strength effects on some reactions involving sulfate radical. J. Phys. Chem., 1996, 100, 9780–9787.
13.
LussierR.L., RisenW.M., and EdwardsJ.O.The photochemistry of peroxodiphosphates. The oxidation of water and two alcohols. J. Phys. Chem., 1970, 74, 4039–4046.
14.
RossoJ.A., GonzalezM.C., and MártireD.O.Photolysis of polyphosphate ions in alkaline aqueous solution. Int. J. Chem. Kinet, in press.
15.
GonzalezM.C., MártireD.O., and BraunA.M.Aqueous phase kinetic studies involving highly reactive species of environmental interest. Rec. Res. Devel. Photochem. Photobiol., 2, 1998, 25–45 and references therein.
16.
WardmanP.Reduction potentials of one – electron couples. J. Phys. Chem. Ref. Data, 1989, 18, 1637–1716.
17.
JaysonG.G., ParsonsB.J., and SwallowA.J.Some simple, highly reactive, inorganic chlorine derivatives in aqueous solution. J. Chem. Soc, Faraday Trans. 1, 1973, 69, 1597–1607.
18.
MarchJ.Reactions, mechanisms, and structure. In Advanced Organic Chemistry, pp. 258–259, 4th edn, Wiley-Interscience, New York, 1991, and references therein.
19.
HanschC., and GaoH.Comparative QSAR: Radical reactions of benzene derivatives in chemistry and biology. Chem. Rev, 1997, 97, 2995–3059.
20.
GonzalezM.C., and MártireD.O.Reactions of sulfate radicals with substituted benzenes studied by time-resolved spectroscopy. A structure-reactivity correlation analysis. Asi. J. Spectrosc., 1999, 3, 125–128.
21.
NetaP., MadhavanV., ZemelH., and FessendenR.W.Rate constants and mechanism of reaction of SO4·- with aromatic compounds. J. Am. Chem. Soc., 1977, 99, 163–164.
22.
MohanH., MudaliarMohan, AravindakumarC.T., RaoB.S., and MttalJ.P.Studies on structure-reactivity in the reaction of HO radicals with substituted halobenzenes in aqueous solutions. J. Chem. Soc. Perkin Trans., 21991, 1387–1392.
23.
MaruthamuthuP., and TaniguchiH.An in-situ photolysis-electron spin resonance study of some reactions of phosphate radicals. J. Phys. Chem., 1977, 81, 1944–1948.
24.
MohanH., and MittalJ.P.Formation and Reactivity of the radical cation of bromobenzene in aqueous solutions: A pulse radiolysis study. J. Phys. Chem., 1995, 99, 6519–6524.
25.
MohanH., and MittalJ.P.Direct evidence for H+-catalysed dehydration of fluorohy-droxycyclohexadienyl radical: A pulse radiolysis study. J. Chem. Soc. Faraday Trans., 1995, 91, 2121–2126.
26.
SteenkenS., in Free Radicals in Synthesis and Biology. NATO ASI Series C-260, 1989, 220. MnisciF. ed., Kluwer Academic Publishers, Dordrecht, The Netherlands.
27.
MaruthamuthuP., and NetaP., Reactions of phosphate radicals with organic compounds. J. Phys. Chem., 1977, 81, 1622–1625.
28.
von SonntagC., and SchuchmannH.-P.The elucidation of peroxyl radical reactions in aqueous solution with the help of radiation-chemical methods. Angew. Chem. Int. Ed. Engl., 1991, 30, 1229–1253.
29.
NetaP., HuieR.E., and RossA.B.Rate constants for reactions of peroxyl radicals in fluid solutions. J. Phys. Chem. Ref. Data, 1990, 19, 413–513.
30.
MergaG., RaoB.S.M., MohanH., and MttalJ.P.Reactions of OH and SO4·- with some 4 halobenzenes and halotoluenes: A radiation chemical study. J. Phys. Chem., 1994, 98, 9158–9164.
31.
DraperP.B., FoxM.A., PelizettiE., SerponeN.Pulse radiolysis of 2,4,5 trichlorophenol: formation, kinetics and properties of hydrotrichlorocyclohexadyene, trichlorophe-noxyl, and dihydroxytrichlorociclohexadienyl radicals. J. Phys. Chem., 1989, 93, 1938–1943 and references therein.
32.
AdamsG.E., MitchelB.D., and LandE.J.Pulse radiolysis investigations of unimolecular elimination reactions in free radicals produced by OH addition to hydroxy benzenes. Nature, 1966, 211, 293–294.
33.
SwallowA.J. in Progress in Reaction Kinetics, 1979, 9, 195–365.
34.
KochiJ.K. in Free Radicals, vol. 1, KochiJ.K. ed. John Wiley & Sons, New York, 1973.
35.
Karpel Vel LeitnerN, GombertB., Ben AbdessalemR., and KineticsDoré M.and mechanism of the photolytic and OH radical induced oxidation of fluorinated aromatic compounds in aqueous solutions. Chemosphere, 1996, 32, 893–906.
36.
SteenkenS., Topics in Current Chemistry, Vol. 177, Springer-Verlag, Berlin, 1996.
37.
GouldE.S., Mechanism and Structure in Organic Chemistry.Holt, Rinehart and Winston, New York, 1959.
38.
NDRL Radiation Chemistry Data Center, INTERNET compilations, University of Notre Dame, USA. Address:
39.
VillataL.S., RossoJ.A., GonzalezM.C., and MártireD.O.Kinetics of the reactions of O•- and HO· with α, α, α-trifluorotoluene and 4-fluorotoluene. J. Chem. Res., 1997, 172–173.
