Radiolysis of aqueous solutions of ammonium bicarbonate over a large dose range

Oxygen-free aqueous solutions of 0.05 mol dm-3 ammonium and sodium bicarbonate were studied after receiving various doses of 60Co gammas (0.01–400 kGy) or 0.5–20 Gy pulses of 10 Mev electrons. Formate and oxalate were found to be the main radiolytic products, in addition to trace amounts of formaldehyde and an unidentified polymer. A large initial yield of formate in the γ-radiolysis, G(HCOO)=2.2, is due to the reaction COO + HCO3⤦HCOO+CO3. The efficiency of organic synthesis within the large dose range studied is low and is explained by efficient pathways leading to the reformation of bicarbonate, where the reaction COO+CO3 is particularly significant. Computer fitting of the data obtained gives k(COO + HCO3)=(2±0.4) x 103 dm3 mol-1 s-1k(COO+CO3) = (5±1) x 107 dm3 mol-1 s-1k(NH2+HCO3)< 104 dm3 mol-1 s-1, and k(NH2+CO3) = (1.5±0.5) x 109 dm3 mol-1 s-1.