Atmospheric Oxidation of Amines Relevant for Carbon Capture and Storage

在短期和中期，胺基物种从烟气流中捕获燃烧后的二氧化碳将成为减少二氧化碳战略的一个主要组成部分。这种技术的广泛采用是产生重大影响所必需的，它将需要生产成千上万吨胺，随后在生产、运输、使用、回收和处置期间向大气释放少量但数量仍然很大的胺，或在意外释放或工厂故障后释放大量胺。即使是简单胺或已提出用于碳捕获的更复杂胺（例如单乙醇胺- MEA）的大气寿命或降解产物也知之甚少。该项目的总体目标是填补我们在胺的气相氧化方面的知识空白。迄今为止所进行的非常有限的研究表明气相氧化和非均相氧化都很重要。这个项目的重点是气相化学，但我们在利兹的同事和奥斯陆大学的合作者都是异质过程方面的专家，因此两个社区之间将有一个良好的信息流。该项目的第一个组成部分是测量各种胺与OH、NO3、Cl自由基和臭氧（O3）等重要大气氧化剂反应的速率系数。这些速率系数将在孤立条件下测量，重点放在胺氧化过程的第一步。测量将使用激光闪光光解和激光诱导荧光等技术进行。由此得出的速率系数将使我们能够计算出胺在大气中的寿命，从而计算出任何污染的空间扩散。该项目的第二个组成部分将是确定生产第一代和下一代产品的化学机制，用于选定的重要胺，如甲基亚胺。这将通过确定胺的初始自由基攻击位置（例如，对于简单的胺，如CH3NH2，从CH3或NH2基团中提取的H原子的比例是多少？）和通过观察稳定产物的浓度来实现，主要是通过红外光谱。在RNHR基团受到攻击形成NR2自由基后，胺氧化有可能在NR2与NO反应后形成高毒性亚硝胺。通过确定由选定的重要胺与NO和O2形成NR2的速率系数，该项目的第三部分将评估亚硝胺形成的潜力。该项目的最后组成部分是综合上述资料，并将其纳入一个全面的大气化学模型- -总化学机制- -以评估胺对臭氧产生（空气质量和气候变化影响）和其他大气问题作出贡献的可能性。该项目将涉及与工业团体和立法组织的互动。虽然主要关注的是碳捕获产生的胺，但胺的来源多种多样，例如海洋环境，因此该项目具有更广泛的应用和潜力。

Post combustion CO2 capture from flue gas streams by amine based species will form a major component of the strategy for CO2 mitigation in the short and medium term. The wide spread uptake of this technology necessary to make a significant impact will require the production of many thousands of tonnes of amines with consequent atmospheric release either in small but still significant amounts during production, transport, use, recycling and disposal or in larger amounts following accidental release or plant failure. Very little is known about the atmospheric lifetimes or degradation products of even simple amines or the more complex amines that have been proposed for carbon capture (e.g. monoethanolamine - MEA). The overall objective of this project is to fill this gap in our knowledge on the gas phase oxidation of amines. The very limited studies that have taken place to date show that both gas phase and heterogeneous oxidation is important. The focus of this project is gas phase chemistry, but we have colleagues in Leeds and collaborators in the University of Oslo who are experts on the heterogeneous process, so that there will be a good flow of information between the two communities. The first component of the project is the measure the rate coefficients for the reaction of a variety of amines with important atmospheric oxidants such as the OH, NO3 and Cl radicals and ozone (O3). These rate coefficients will be measured under isolated conditions, focusing on just this first step in the amine oxidation process. The measurements will be performed using techniques such as laser flash photolysis and laser induced fluorescence. The resulting rate coefficients will allow us to calculate the atmospheric lifetimes of the amines and hence the spatial spread of any pollution. The second component of the project will be to determine the chemical mechanism for the production of first and subsequent generation products for selected important amines such as MEA. This will be achieved both by determining the position of the initial radical attack on the amine (i.e. for a simple amine such as CH3NH2, what fraction of the H atoms abstracted comes from the CH3 or NH2 groups?) and by observing the concentrations of the stable products, primarily by IR spectroscopy. Amine oxidation following attack at the RNHR group to form NR2 radicals has the potential to form highly toxic nitrosamines following reaction of NR2 with NO. By determining the rate coefficients for NR2 formed from selected important amines, with NO and O2, the third component of the project will asses the potential for nitrosamine formation. The final component of the project is to combine the above information and incorporate into a comprehensive chemical model of the atmosphere - the Master Chemical Mechanism, MCM - to assess the potential for amines to contribute to ozone production (air quality and climate change implications) and other atmospheric issues. The project will involve interactions with industrial groups and legislative organisations. Whilst the primary focus is on amines from carbon capture, amines are produced from a variety of sources - e.g. marine environment, so the project has wider applications and potential.