In the presence of hydrogen peroxide as an oxidizing agent, the heteropoly anions H₆P₂W₁₈O₆₂, H₆P₂Mo₁₈O₆₂, α-K₃PW₉Mo₃O₄₀, α-K₇PW₉Mo₂O₃₉, H₄PMo₁₁VO₄₀, H₅PMo₁₀V₂O₄₀ and H₆PMo₉V₃O₄₀ were studied as catalysts for the N-oxidation of picolinic acid, in various solvents such as toluene, benzene and carbon tetrachloride. The highly selective oxidation, gave good to excellent yields of the related N-oxide along with decarboxylation at 2-position of ring. Among the catalysts tested, α-K₃PW₉Mo₃O₄₀ catalyzed the selective N-oxidation into related N-oxide product most efficiently. The effect of some operative variables, such as the mole numbers of hydrogen peroxide, amount of the catalyst, and the reaction time was studied. The reaction conditions were optimized.

中文翻译：

---

杂多酸（包括钼和钨）存在下吡啶甲酸的催化N氧化

在过氧化氢的存在下作为氧化剂，杂多阴离子ħ ₆ P ₂ W ^ ₁₈ ø ₆₂，H ₆ P ₂沫₁₈ ø ₆₂，α-K ₃ PW ₉沫₃ ö ₄₀，α-K ₇ PW ₉沫₂ O ₃₉，H ₄ PMo ₁₁ VO ₄₀，H ₅ PMo ₁₀ V ₂ O ₄₀和H ₆ PMo ₉ V ₃研究了O ₄₀作为在各种溶剂（例如甲苯，苯和四氯化碳）中N-氧化吡啶甲酸的催化剂。高度选择性的氧化使相关的N-氧化物具有优异的优良收率，同时在环的2位脱羧。在所测试的催化剂中，α-K ₃ PW ₉沫₃ ö ₄₀最有效地催化的选择性N-氧化成相关的N-氧化物产物。研究了一些操作变量的影响，例如过氧化氢的摩尔数，催化剂的量和反应时间。优化反应条件。