Phase and dose effects of13N in pile-irradiated propionic-d2 acid

A sharp phase effect on the yields of¹³NH₄ ⁺ and¹³NO₂ ^– has been observed in propionic-d₂ acid irradiated in a reactor similarly to the other carboxylic acids previously reported. In the formation of¹³NH₄ ⁺,¹³NO₂ ^– and ¹³N]amide, there is no (H/D)-isotope effect between CH₃CD₂COOH and C₂D₅COOD systems unlike for protiated and deuterated benzene and cyclohexane. With a rise in irradiation dose from 100 to 400 MGy, the yield of¹³NH₄ ⁺ increased, but that of¹³NO₂ ^– decreased in proportion to the dose. The dose effect was clear more in liquid phase than in frozen one. The results are in harmony with the reaction mechanism proposed in our previous works.