和表面活性物质是否会影响沿海大气颗粒的增长?
Kristijan Vidović1,2, Samo Hočevar1, Irena Grgić1
1National Institute of Chemistry, Department of Analytical Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia.
Heliyon
|June 3, 2024
概括
亚得里亚海的新粒子形成 (NPF) 是由和有机化合物驱动的,而不是硫酸. 这项研究揭示了克罗地亚沿海地区频繁发生的NPF事件和表面活性物质影响的颗粒生长.
科学领域:
- 大气化学和物理大气化学和物理
- 环境科学 环境科学
- 气溶科学 气溶科学
背景情况:
- 新粒子形成 (NPF) 是大气粒子和云凝聚核 (CCN) 的关键来源.
- 了解沿海地区的NPF和颗粒生长是有限的,特别是在亚得里亚海.
- 之前的研究没有在这个特定的地理区域广泛记录NPF事件.
研究的目的:
- 研究和描述亚得里亚海沿海新粒子形成 (NPF) 和粒子增长事件.
- 阐明NPF和克罗地亚Rogoznica颗粒生长背后的化学机制和影响因素.
- 引入和应用一种用于确定粒子增长率的新方法.
主要方法:
- 在克罗地亚Rogoznica的一个沿海站进行了在线测量和离线颗粒收集.
- 对收集的粒子样本进行了详细的物理化学表征和化学分析.
- 采用了一种新的半实证的第1导数方法来确定时间解析的粒子增长率.
主要成果:
- 在夏季期间,在亚得里亚海中部记录了频繁的NPF和随后的粒子生长事件.
- 鉴定出化合物和有机碳 (OC) 是导致粒子生长的关键因素,与表面活性物质 (SAS) 一起.
- 在NPF事件中观察到较高的OC度和超细颗粒中的存在;硫酸盐水平没有显著差异.
结论:
- 这项研究提供了在亚得里亚海沿岸地区频繁出现的NPF和颗粒生长的第一个证据.
- ,有机化合物和SAS在沿海NPF和颗粒生长中发挥着重要作用,硫酸似乎不那么重要.
- 这些发现提高了对沿海环境中的大气过程和化学物种在粒子形成中的复杂相互作用的理解.
相关概念视频
01:27Radical Substitution: Allylic Bromination
5.1K
In organic synthesis, the formation of products can be altered by changing the reaction conditions. For example, a dibromo addition product is formed when propene is treated with bromine at room temperature. In contrast, propene undergoes allylic substitution in non-polar solvents at high temperatures to give 3-bromopropene. In order to avoid the addition reaction, the bromine concentration must be kept as low as possible throughout the reaction. This can be achieved using N-bromosuccinimide...
5.1K
02:41Formation of Halohydrin from Alkenes
12.9K
An alkene, such as propene, reacts with bromine in the presence of water to yield a halohydrin. Halohydrins contain a halogen and a hydroxyl group attached to adjacent carbons. When the halogen is bromine, it is called a bromohydrin, while a chlorohydrin has chlorine as the halogen.
12.9K
02:46Halogenation of Alkenes
15.5K
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
15.5K
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
3.3K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.3K
02:35Regioselectivity of Electrophilic Additions-Peroxide Effect
8.5K
In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
8.5K
01:17Radical Anti-Markovnikov Addition to Alkenes: Mechanism
3.7K
The reaction of hydrogen bromide with alkenes in the presence of hydroperoxides or peroxides proceeds via anti-Markovnikov addition. The radical chain reaction comprises initiation, propagation, and termination steps.
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy...
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy...
3.7K