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Dynamics of Gas-Liquid Reactions; The Pseudo-Surface Approach

气液反应动力学；

基本信息

批准号：
EP/J002534/1
负责人：
Stuart Greaves
金额：
$ 135万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FJ002534%2F1
关键词：
Dynamics Gas Liquid Reactions Pseudo

项目摘要

Chemical reactions require a collision between two chemical species, and have been widely developed and exploited in solution by synthetic chemists to make a variety of products such as plastics and drugs. Chemical interactions are studied in greater detail by physical chemists, who often work with gases in order to isolate individual molecular collisions for quantitative study. However the fundamental dynamics of dual-phase (gas-liquid) interactions are poorly understood and, to date, have received only limited attention. Gas-liquid interactions are of particular importance to a wide variety of physical processes, ranging from respiration in living organisms (which relies on uptake of oxygen from air, into the blood) to distillation, gas chromatography, and atmospheric chemistry at the surfaces of aerosol particles (where for example water droplets in air can absorb sulfuric acid to from acid rain) and the Earth's oceans. The aim of the proposed research is to improve the fundamental understanding of gas-liquid surface interactions by employing a novel experimental strategy; using a large, but volatile, flexible molecule as a simplified proxy for a liquid surface (a pseudo-surface). This will allow chemical reactions that occur at the gas-liquid interface to be studied in unprecedented detail using high resolution laser based techniques coupled with imaging methods. The imaging allows pictures to be taken of the fate of products of a chemical reaction, which will allow us to develop in-depth understanding of the mechanisms involved. This project will focus on the construction and use of a unique, compact imaging experiment that will be the first of its kind in the UK. Using the experiment we can measure the direction and speed with which any products of reactions fly. This will allow us to gain in-depth knowledge of the different possible reaction mechanisms of collisions of molecules with pseudo-surfaces. The simplest pathway is a single collision reaction, called a direct mechanism. Some colliding atoms or molecules are trapped on the surface, however, undergoing multiple collisions before reacting (a so called trapping-desorption mechanism), and in extreme cases the pseudo-surface adsorbs the other reagent. The football / apple tree analogy is helpful here: imagine if you kick a football into an apple tree, it could come out straight away, bouncing off a branch, bringing an apple with it (direct mechanism), or it could get temporarily caught bouncing from branch to branch before leaving with an apple (trapping-desorption), or it could become wedged between the branches. The work proposed here will study the football and apple tree problem in detail and use it as a model to investigate the football and orchard problem (the real liquid, where lots of identical molecules (apple trees) make up the surface). This analogy can be extended to use rugby and other shaped balls to represent different incoming atoms/molecules/radicals that we intend to study. The research will have a profound impact on the understanding of surface interactions, and will be of benefit to a broad community of researchers in Chemistry, Physics, Engineering, and ultimately Life Sciences, with interest in gas-liquid interfaces.

化学反应需要两种化学物质之间的碰撞，并且已经被合成化学家广泛开发和利用，以制造各种产品，如塑料和药物。物理化学家更详细地研究化学相互作用，他们经常与气体一起工作，以分离单个分子的碰撞进行定量研究。然而，双相（气-液）相互作用的基本动力学知之甚少，迄今为止，只得到有限的关注。气液相互作用对各种各样的物理过程都特别重要，从生物体的呼吸（依赖于从空气中吸收氧气进入血液）到蒸馏，气相色谱，以及气溶胶颗粒表面的大气化学（例如空气中的水滴可以吸收硫酸形成酸雨）和地球的海洋。拟议研究的目的是通过采用一种新的实验策略来提高对气液表面相互作用的基本理解;使用一种大的，但易挥发的，灵活的分子作为液体表面（伪表面）的简化代理。这将允许使用高分辨率激光技术结合成像方法以前所未有的细节研究气液界面处发生的化学反应。成像允许拍摄化学反应产物的命运，这将使我们能够深入了解所涉及的机制。该项目将重点建设和使用一个独特的，紧凑的成像实验，这将是第一次在英国。利用这个实验，我们可以测量任何反应产物飞行的方向和速度。这将使我们能够深入了解分子与伪表面碰撞的不同可能反应机制。最简单的途径是一个单一的碰撞反应，称为直接机制。然而，一些碰撞的原子或分子被捕获在表面上，在反应之前经历多次碰撞（所谓的捕获-脱附机制），在极端情况下，伪表面会吸附其他试剂。足球和苹果树的类比在这里很有帮助：想象一下，如果你把足球踢到苹果树上，它可能会立刻跳出来，从一根分支上弹起来，带着一个苹果（直接机制），或者它可能会在带着一个苹果离开之前暂时从一根分支跳到另一根分支上（陷阱-解吸），或者它可能会卡在树枝之间。这里提出的工作将详细研究足球和苹果树问题，并将其作为模型来研究足球和果园问题（真实的液体，其中许多相同的分子（苹果树）组成表面）。这个类比可以扩展到使用橄榄球和其他形状的球来代表我们想要研究的不同的原子/分子/自由基。这项研究将对理解表面相互作用产生深远的影响，并将有利于化学，物理，工程和最终生命科学领域的广泛研究人员，并对气液界面感兴趣。