Exploring the Physical Chemistry of the Catalysis-Based All-Vapor Instant Formation of Gas Hydrates at Moderate P and T (180-220 K)

俄克拉荷马州立大学的Paul Devlin教授受化学系化学结构、动力学和机制项目的支持，研究笼形水合物的基本物理和化学性质。笼形物水合物的形成，通常是由液态水或冰形成的，是如此缓慢，以至于常常阻碍对这一过程的速率和机制的研究。最令人兴奋和最有希望的研究发现是一种全新的水合物形成方法，可以将反应时间缩短到亚秒级。通常缓慢的混合过程已被分流使用全蒸汽方法与组分客体分子充分混合水蒸气。脉冲进入冷室，蒸汽迅速凝结成水溶液滴，立即结晶为气溶胶的100%气体水合物颗粒。在目前的知识阶段，催化剂仍然是必需的，但在该项目的这一阶段所寻求的全蒸汽方法的进步可能有助于以下方面的技术发展：A)从丰富的甲烷水合物海洋沉积物中生产甲烷；b)在大大降低的压力下，作为水合物主体的甲烷和二氧化碳等气体的浓缩/储存。例如，研究表明，包括二氧化碳在内的潮湿空气是一种蒸汽混合物，只要有催化剂，它就适合于气体水合物的全蒸汽形成。水包合物/气体水合物最简单地描述为一个由水分子组成的冰状主体晶格，其中包含了小笼子，作为分子大小的陷阱，容纳小的有机或无机客体分子。由于其丰富的自然资源及其对环境和技术的重大影响，在过去的一个世纪里，它们一直是许多研究的对象。人们对它们的发生和物理性质了解甚多；较少涉及它们在氢键化学中的作用及其形成机制。在这个项目中，Devlin教授和他的本科生研究助理将致力于开发天然气水合物的形成和控制方法，以促进天然气水合物科学在能源工业和环境中的应用，以控制二氧化碳和甲烷等气体。

Prof. Paul Devlin of Oklahoma State University is supported by the Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division to study the basic physical and chemical properties of clathrate hydrates. Clathrate hydrate formation, typically from liquid water or ice, is so slow as to often discourage studies of the rates and mechanisms of the process. The most exciting and promising discovery from research supported under prior awards is a completely new method of hydrate formation that reduces the reaction time to the subsecond scale. A generally slow mixing process has been shunted by using an all-vapor methodology with component guest molecules fully mixed with water vapor. Pulsed into a cold chamber the vapor quickly condenses to aqueous solution droplets that instantly crystallize as 100% gas-hydrate particles of an aerosol. A catalyst is still required at the current stage of knowledge, but advances in the all-vapor method sought in this phase of the project may aid technological developments in a) the production of methane from abundant ocean-sediment deposits of methane hydrate, and b) the concentration/storage of gases such as methane and CO2 as hydrate guests at greatly reduced pressures. It has been shown, for example, that humid air including CO2 is a vapor mixture suited to the all-vapor formation of a gas hydrate provided a catalyst is includedA clathrate/gas hydrate is most simply described as a host ice-like lattice of water molecules with incorporated small cages that serve as molecule-sized traps holding small organic or inorganic guest molecules. Because of an exceptional abundance in nature and their significant environmental and technological implications, they have been an object of many investigations over the past century. Much is known about their occurrence and physical properties; less about their participation in H-bond chemistry and the mechanisms of their formation. In this project, Prof. Devlin and his undergraduate research assistants will pursue the development of methods of gas-hydrate formation and control that will facilitate gas -hydrate science applications for controlling gases such as carbon dioxide and methane in the energy industry and the environment.