Kinetic isotope effects occurring during carbonate precipitation impact the accuracy of paleoclimate records. One rate-limiting process is CO absorption, which, at high pH, primarily proceeds through hydroxylation, where aqueous CO and OH react to form HCO. In this study, we investigated the triple oxygen isotope fractionation (O/O and O/O) associated with the hydroxylation reaction. We experimentally determined the extent of the kinetic isotope effects superimposed on the reacting CO and OH during hydroxylation, using high-pH precipitation reactions. These results were compared to the equilibrium triple oxygen isotope fractionation between HO and OH modeled using quantum chemical computations.

中文翻译：

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CO2 羟基化的三重氧同位素系统学

碳酸盐沉淀过程中发生的动力学同位素效应影响古气候记录的准确性。一种限速过程是 CO 吸收，在高 pH 条件下，CO 吸收主要通过羟基化进行，其中 CO 水溶液和 OH 反应形成 HCO。在本研究中，我们研究了与羟基化反应相关的三氧同位素分馏（O/O 和 O/O）。我们使用高 pH 沉淀反应，通过实验确定了羟基化过程中反应 CO 和 OH 上的动力学同位素效应叠加的程度。将这些结果与使用量子化学计算建模的 H2O 和 OH 之间的平衡三氧同位素分馏进行比较。