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本文研究了1,2,2,6,6-五甲基哌啶醇在异辛烷溶液中的光稳定作用。实验结果表明:五甲基哌啶醇具有和四甲基哌啶醇基本相同,而此四甲基哌啶醇氮氧自由基略优的光稳定效率;五甲基哌啶醇和四甲基哌啶醇一样,在光稳定作用过程中产生氮氧自由基,并且氮氧自由基浓度变化经历了一个最大值,但其积累的速度及达到的浓度极大值均比四甲基哌啶醇的场合为低。实验还发现,五甲基哌啶醇在光稳定过程中产生一个稳定中间产物——N-氧化-1,2,2,6,6-五甲基哌啶醇。据此,提出了五甲基哌啶醇首先转化为N-氧化物,进而转化为氮氧自由基的两步作用机理。
In this paper, the photostabilization of 1,2,2,6,6-pentamethylpiperidin in isooctane was studied. The experimental results show that: pentamethylpiperidine alcohol and tetramethylpiperidin alcohol is basically the same, and this tetramethylpiperidine alcohol nitroxyl radical slightly superior light stability efficiency; pentamethylpiperidine alcohol and tetramethylpiperidine Like the alcohol, nitroxides were produced during photostabilization and the concentration of nitroxides experienced a maximum, but the rate of accumulation and the maximum reached were higher than that of tetramethylpiperidin Occasion is low. The experiment also found that pentamethylpiperidin in the photostabilizing process to produce a stable intermediate - N-oxide-1,2,2,6,6-pentamethylpiperidinol. Accordingly, a two-step mechanism of pentamethylpiperidinol conversion to N-oxide and then to nitroxide is proposed.