铜吡啶配合物催化合成1-甲氧基-2,2,6,6-四甲基哌啶-4-醇

目前1-烷氧基-2,2,6,6-四甲基哌啶基化合物的合成主要是以醛酮法为主。醇法合成虽然醇价格便宜，但合成效率很低。为解决这一问题，本文对醇法合成工艺进行了深入探讨，并以乙醇和4-羟基-2,2,6,6-四甲基哌啶氮氧自由基（ZJ-701）为原料，30%过氧化氢为氧化剂，氯化铜和吡啶配合物为催化剂，通过氧化和自由基偶合合成了1-甲氧基-2,2,6,6-四甲基哌啶-4-醇，通过红外光谱、核磁共振谱和质谱表征了其结构。通过实验进一步优化了反应时间、温度等一系列合成条件。研究结果表明：当反应时间为12h，反应温度为78℃，n(ZJ-701)∶n(乙醇)∶n(H₂O₂)∶n(CuCl₂)∶n(吡啶)=1∶39.25∶17.01∶0.034∶0.36时，产品产率最高，为60.6%，质量分数为98.8%，熔点为87～90℃。该方法具有原料乙醇便宜易得、反应条件温和、产品提纯容易等优点。

Catalytic synthesis of 1-methoxy-2,2,6,6-tetramethylpiperidine-4-ol by copper complex of pyridine

1-alkoxy-2,2,6,6-tetramethylpiperidinyl compounds are currently synthesized by using aldehydes and ketones as the main raw materials. Alcohol synthesis has the advantage of low cost of raw materials, but the efficiency is rather low. In order to solve this problem, the alcohol synthesis method was deeply discussed, and 1-methoxy-2,2,6,6-tetramethylpiperidine-4-ol was synthesized through oxidation and free radical coupling reactions by using 4-hydroxy-2,2,6,6-tetramethyl-piperidinooxy (ZJ-701) and ethanol as raw materials, 30% H₂O₂ as oxidant, Cu complex of pyridine as catalyst. The product was characterized by IR, ¹H NMR, ¹³C NMR and MS. The synthesis conditions, such as reaction time and temperature, were further optimized through designed experiments. The results showed that when the mole ratio of n(ZJ-701)∶n(ethanol)∶n(H₂O₂)∶n(CuCl₂)∶n(pyridine) was 1∶39.25∶17.01∶0.034∶0.36, the reaction time was 12h, and the reaction temperature was 78℃, the yield of the product reached 60.6%, with the purity of 98.8% and melting point of 87—89℃. The advantages of such alcohol synthesis are that the raw ethanol is cheap and easy to obtain, the reaction conditions are mild, and the products are easy to purify.