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ATMOCHEM - Reactivity of Oxygenated Volatile Organic Compounds (ROVOC): Esters

ATMOCHEM - 含氧挥发性有机化合物 (ROVOC) 的反应性：酯类

基本信息

批准号：
83085079
负责人：
Dr. Ian Barnes
金额：
--
依托单位：
Fachgruppe Chemie und Biologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2008
资助国家：
德国
起止时间：
2007-12-31 至 2012-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/83085079?language=en
关键词：
ATMOCHEM Reactivity Oxygenated Volatile Organic

项目摘要

Oxygenated volatile organic compounds (OVOCs) are omnipresent in the atmosphere. Esters (alkyl alkanoates, e.g. RC(O)OR, R = alkyl groups) are an important class of OVOC with both natural and anthropogenic sources. Esters made up of long chain carboxylic acids are the main constituents of animal- and plant-derived waxes and they also occur naturally in fruits and flowers. Various types of esters are used extensively by industry as solvents in chemical processing. The quest for renewable fuels has seen an increase in the use of biodiesel fuels, which typically consist of methyl and ethyl esters of fatty acids. Esters can also be produced in situ in the atmosphere from, for example, the oxidation of ethers. Few measurements of esters in the atmosphere have been made but those measurements, which have been made, confirm the presence of substantial levels of esters in the atmosphere.Investigations on the atmospheric chemistry of esters to date have been limited to temperature dependent studies of the OH radical kinetics of a number of linear and branched alkyl acetates and room temperature studies of the products from the OH radical or Cl-atom initiated oxidation of a few of these acetates. Studies on methylacetate have shown that the product yield distribution is very temperature dependent. Although this limited set of data has been used been used to improve the structure-activity relationship (SAR) for alkyl esters at 298 K it is clear that there is a definite need for further refine of the SAR for esters particularly with respect to temperature dependence.The project has the overall aim of improving the kinetic, product and mechanistic database for the reactions of OH radicals with a variety of esters as a function of temperature over the range 225-372 K and will use this information to further develop and refine the SAR for esters. The project will consist of the following components: i) determination of OH rate coefficients using absolute and relative methods as a function of temperature; ii) determination of the products of the reactions as a function of temperature and O2 partial pressure; iii) construction of explicit and simplified reaction mechanisms for models; iv) development of SAR for a wider range of ester types applicable over the temperature range 225-372 K.

含氧挥发性有机化合物（OVOCs）在大气中无处不在。酯类（烷基烷烃酸酯，如RC(O)OR, R =烷基）是一类重要的OVOC，既有自然来源，也有人为来源。由长链羧酸组成的酯是动物和植物来源的蜡的主要成分，它们也自然存在于水果和花卉中。各种类型的酯在工业上广泛用作化学加工的溶剂。对可再生燃料的追求使生物柴油燃料的使用有所增加，这种燃料通常由脂肪酸的甲酯和乙酯组成。酯也可以在大气中就地生成，例如，通过氧化醚。人们对大气中的酯类物质进行了很少的测量，但这些已经进行的测量证实了大气中存在大量的酯类物质。迄今为止，对酯类大气化学的研究仅限于对一些线性和支链烷基乙酸酯的OH自由基动力学的温度依赖性研究，以及对其中一些乙酸酯的OH自由基或cl原子引发氧化的产物的室温研究。对乙酸甲酯的研究表明，产物产率分布与温度密切相关。虽然这一有限的数据集已经被用来改善298 K时烷基酯的构效关系（SAR），但很明显，酯的构效关系还需要进一步改进，特别是在温度依赖性方面。该项目的总体目标是在225-372 K范围内改善OH自由基与各种酯反应的动力学、产物和机理数据库，并将利用这些信息进一步开发和完善酯的SAR。该项目将包括以下部分：i)使用绝对和相对方法确定OH速率系数作为温度的函数；ii)测定反应产物随温度和O2分压的函数；Iii)构建明确简化的模型反应机理；iv)开发适用于225-372 K温度范围内的更广泛的酯类型的SAR。