Stabilized Criegee intermediates react with organic acids in the gas phase and at the air–water interface to form a class of ester hydroperoxides, α-acyloxyalkyl hydroperoxides (αAAHPs). A number of recent studies have proposed the importance of αAAHPs to the formation and growth of secondary organic aerosol (SOA). The chemistry of αAAHPs has not been investigated due to a lack of commercially available chemical standards. In this work, the behavior of αAAHPs in condensed phases is investigated for the first time. Experiments were performed with two synthesized αAAHP species. αAAHPs decomposed rapidly in the aqueous phase, with the rate highly dependent on the solvent, temperature, solution pH, and other compounds present in the solution. The measured 1^st-order decomposition rate coefficient varied between 10^–3 and 10^–5 s^–1 under the conditions examined in this work. Elucidation of the reaction mechanism is complicated by byproducts arising from the synthetic procedure, but observations are consistent with a base-catalyzed hydrolysis of αAAHPs. The rapid hydrolysis of αAAHPs observed in this work implies their short lifetimes in ambient cloud and fog waters. Decomposition of αAAHPs likely gives rise to smaller peroxides, such as H₂O₂. The loss of αAAHPs is also relevant to filter extraction, which is commonly practiced in laboratory experiments, potentially explaining contradictory results reported in the existing literature regarding the importance of αAAHPs in SOA.

中文翻译：

---

由Criegee中间体和有机酸引起的氢过氧化物酯的快速水相水解

稳定的Criegee中间体在气相和空气-水界面与有机酸反应，形成一类酯氢过氧化物，即α-酰氧基烷基氢过氧化物（αAAHPs）。最近的许多研究提出了αAAHPs对次级有机气溶胶（SOA）的形成和生长的重要性。由于缺乏市售的化学标准品，因此尚未对αAAHP的化学性质进行研究。在这项工作中，首次研究了αAAHP在凝聚相中的行为。用两种合成的αAAHP物种进行了实验。αAAHPs在水相中迅速分解，分解速率高度依赖于溶剂，温度，溶液pH值和溶液中存在的其他化合物。所测量的1^日10之间阶分解速率系数变化^–3和10 ^–5 s ^–1在本工作中研究的条件下。阐明了反应机理，使合成过程中产生的副产物复杂化，但观察结果与碱催化的αAAHPs水解相一致。在这项工作中观察到的αAAHPs的快速水解意味着它们在环境云和雾水中的寿命很短。αAAHPs的分解可能会产生较小的过氧化物，例如H ₂ O ₂。αAAHPs的损失也与过滤器提取有关，后者是实验室实验中普遍采用的方法，有可能解释了现有文献中有关αAAHPs在SOA中的重要性的报道相互矛盾的结果。