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用核磁红外、质谱等方法证实了某些市售的5-羟基戊醛在室温下主要以其异构体2-羟基四氢吡喃形式存在,并对其~(13)C、~1H-NMR谱线进行了归属。升高温度引起2-羟基四氢吡喃开环异构化生成5-羟基戊醛。140℃时按一级反应速度公式求出了异构化速度常数。
Some commercially available 5-hydroxypentanals were confirmed to be mainly exists in the form of 2-hydroxytetrahydropyran at room temperature by NMR, MS and other methods, and their ~ (13) C, ~ 1H- NMR spectra were assigned. Elevated temperature causes ring opening isomerisation of 2-hydroxytetrahydropyran to 5-hydroxypentanal. The isomerization rate constant was calculated from the first-order reaction rate at 140 ° C.