Synthesis of diols by means of the gamma irradiation of α ketoacids in aqueous solutions

Photoinduced Oligomerization of Aqueous Pyruvic Acid

“…Regardless of whether the CH 3 C(O)C(O)O· radical ensues after electron transfer, proton-coupled electron transfer, or H-atom transfer processes, the fact remains that its ultrafast decarboxylation ( k 9 ∼ 10 12 s -1 ): , could not be intercepted by any of the radical scavengers used under these conditions. , The acetyl radical is rather stable to decarbonylation (CH 3 CO· → CH 3 · + CO, k dec ∼ 0.01−1 s -1 ) , but is rapidly hydrated in aqueous solution . According to Scheme , A is formed in the self-association of K • radicals. − The formation of B involves the addition of K • to PA, to either the keto form or its enol, followed by the subsequent association of C with the acetyl radical into the multifunctional dicarboxylic acid, D (220 Da). The rapid decarboxylation of D may proceed from the β-oxocarboxyl moiety into B1 − or, less likely, from the α-hydroxycarboxyl moiety into B2 .…”

“…67 According to Scheme 1, A is formed in the self-association of K • radicals. [68][69][70] The formation of B involves the addition of K ˙-(OH) 2 +O 2 ] ) 7.7 × 10 8 M -1 s -1 75 and k sc (K -‚+O 2 ) ) 2.6 × 10 9 M -1 s -1 . 51,74 Some delocalized alkyl radicals, such as the methyl radical derived from N-nitrosodimethylamine (k sc ) 5.3 × 10 6 M -1 s -1 ), 76 react with O 2 in water with rate constants that are considerably smaller than the diffusion-controlled limit.…”