N-氧化烟酸的合成

Synthesis of Nicotinic Acid N-oxide

以烟酸为原料 ,在冰醋酸溶液中 ,用双氧水氧化合成N -氧化烟酸。实验发现在合成中加入一种共沸剂 ,可以降低反应的回流温度 ,同时 ,也可将反应生成的水不断带走 ,使转化率增大 ,并且具有合成工艺简单 ,溶剂可以重复使用 ,无三废等特点。适宜的反应条件为 :烟酸 :双氧水 :冰醋酸的摩尔比为 1∶1 .5∶3 ,共沸剂A或B的用量为 3 0ml,反应时间为 5h,收率 92 .0 %。

Nicotinic acid N-oxide was prepared by oxidizing nicotinic acid in glacial acetic acid by 30 % H 2O 2.This technology showed many advantages, such as the synthetic method was simplified, the solvent may be used repeatedly and the pollution was very low. The suitable reaction conditions were that molar ratio of nicotinic acid to H 2O 2, AcOH was 1∶1.5∶3, amount of azeotropic solvent A or B was 30 ml, reaction time was 5h and the yield was 92.0 %.