作者:Charles L. Perrin、Agnes Flach、Marlon N. Manalo
DOI:10.1021/ja301867s
日期:2012.6.13
Malonic anhydrides decompose at or below room temperature, to form a ketene and carbon dioxide. Rate constants for the thermal decomposition of malonic, methylmalonic, and dimethylmalonic anhydrides were measured by NMR spectroscopy at various temperatures, and activation parameters were evaluated from the temperature dependence of the rate constants. Methylmalonic anhydride is the fastest, with the
丙二酸酐在室温或低于室温时分解,形成乙烯酮和二氧化碳。丙二酸、甲基丙二酸和二甲基丙二酸酐的热分解速率常数通过 NMR 光谱在不同温度下进行测量,活化参数根据速率常数的温度依赖性进行评估。甲基丙二酸酐最快,ΔH(‡)最低,二甲基丙二酸酐最慢。对甲基数量的非线性依赖性是根据协调的 [2(s) + (2(s) + 2(s))] 或 [2(s) + 2(a)] 环回复进行讨论的由计算支持的扭曲过渡状态结构。