Reactions of phosphate radicals with organic compounds. [Gamma rays and electron beams]

Journal Article · Thu Aug 25 04:00:00 UTC 1977 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100532a004· OSTI ID:7316838

Maruthamuthu, P; Neta, P

Phosphate radicals in the three acid-base forms, H/sub 2/PO/sub 4/, HPO/sub 4//sup -/, and PO/sub 4//sup 2 -/, were produced by the reaction of hydrated electrons with peroxodiphosphate ions at pH values of 3-4, 7-9, and 12, respectively. Rate constants for the reactions of these radicals with organic compounds were determined by following the rate of decay of the phosphate radical absorption in the presence of increasing concentrations of the substrate. Rates of reaction of H/sub 2/PO/sub 4/ were found to be higher than those of HPO/sub 4//sup -/ and PO/sub 4//sup 2 -/ by a factor of approximately 4-10, while the latter radicals have similar rates. The rate constants for hydrogen abstraction from aliphatic compounds ranged from approximately 10/sup 5/ M/sup -1/ s/sup -1/ for acetic acid and 2-methyl-2-propanol to approximately 10/sup 8/ M/sup -1/ s/sup -1/ for 2-propanol and formate. Addition to a double bond was not faster but reaction with aromatic compounds reached a rate constant greater than 10/sup 9/ M/sup -1/ s/sup -1/ for the most reactive compounds. The effects of substituents were found to be similar for H/sub 2/PO/sub 4/ and SO/sub 4//sup -/ and both radicals are suggested to react with the aromatic ring by one-electron transfer to the inorganic radical. In hydrogen abstraction reactions H/sub 2/PO/sub 4/ (and SO/sub 4//sup -/) were found to react with rate constants approximately 10-100 times lower than those of OH and to have a selectivity about three times higher than that of OH. Radiolytic chain decomposition of peroxodiphosphate in the presence of some organic compounds was also studied.

• Research Organization: Notre Dame Univ., IN
• OSTI ID: 7316838
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 81:17; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ACID PHOSPHATES
BEAMS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
G VALUE
GAMMA RADIATION
IONIZING RADIATIONS
LEPTON BEAMS
LEPTONS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PARTICLE BEAMS
PEROXIDES
PHOSPHATES
PHOSPHORUS COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS
SOLVATED ELECTRONS