美国加州理工学院Christopher M. Kenseth团队报道了颗粒相吸积在蒎烯二级有机气溶胶中形成二聚酯。相关研究成果发表在2023年11月17日出版的国际知名学术期刊《科学》。

二次有机气溶胶（SOA）在大气中普遍存在，在气候、空气质量和健康方面发挥着关键作用。通过吸积反应生产低挥发性二聚化合物是SOA形成的一个关键方面。然而，尽管进行了广泛的研究，SOA中二聚体的结构以及形成机制在很大程度上仍未得到表征。

该文中，研究人员通过独立合成真实的标准物，阐明了SOA中几种主要二聚酯的结构，这些二聚酯来自α-蒎烯和β-蒎烯的臭氧分解，它们是全球SOA的重要来源。研究发现这些二聚酯是在颗粒相中形成的，并提出了醇与环状酰基过氧半缩醛亲核加成的机制。这种化学可能代表了在环境SOA中生成二聚体化合物的通用途径。

附：英文原文

Title: Particle-phase accretion forms dimer esters in pinene secondary organic aerosol

Author: Christopher M. Kenseth, Nicholas J. Hafeman, Samir P. Rezgui, Jing Chen, Yuanlong Huang, Nathan F. Dalleska, Henrik G. Kjaergaard, Brian M. Stoltz, John H. Seinfeld, Paul O. Wennberg

Issue&Volume: 2023-11-17

Abstract: Secondary organic aerosol (SOA) is ubiquitous in the atmosphere and plays a pivotal role in climate, air quality, and health. The production of low-volatility dimeric compounds through accretion reactions is a key aspect of SOA formation. However, despite extensive study, the structures and thus the formation mechanisms of dimers in SOA remain largely uncharacterized. In this work, we elucidate the structures of several major dimer esters in SOA from ozonolysis of α-pinene and β-pinene—substantial global SOA sources—through independent synthesis of authentic standards. We show that these dimer esters are formed in the particle phase and propose a mechanism of nucleophilic addition of alcohols to a cyclic acylperoxyhemiacetal. This chemistry likely represents a general pathway to dimeric compounds in ambient SOA.

DOI: adi0857

Source: https://www.science.org/doi/10.1126/science.adi0857