Evaluation of Rate Parameters during Heterogeneous Catalysisin Supercritical Fluids

超临界流体多相催化速率参数的评估

• 批准号: 8909940
• 负责人: Martin Abraham
• 金额: $ 7.48万
• 依托单位: University of Tulsa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8909940&HistoricalAwards=false
• 关键词: Evaluation; Rate; Parameters; during; Heterogeneous

The unique properties of a fluid near its critical point can be utilized to alter principle reaction pathways within a reacting system. The unusual solvent properties of a supercritical fluid (SCF) can facilitate reactions which cannot be achieved in traditional solvents. This happens because the supercritical solvent provides an environment where mass transfer limitations are eliminated due to the solvent's physical properties, which lie intermediate between a gas and a liquid. Thus, the high solvent density relative to a gas combined with high solute diffusivity relative to diffusivity in a liquid, create an environment where high concentrations of solute can dissolve in the solution and yet severe mass transfer limitations are absent. The goal of this research project are to investigate the effect of SCF solvents on the rate processes which control the overall rate of a catalytic reaction. Specifically, the PI will attempt to measure the rate of adsorption, the rate intraparticle diffusion, and the adsorptive capacity of the catalyst under supercritical conditions. He will use chromatographic techniques to measure the desired rate parameters under a variety of experimental conditions and consider the overall effect of the SCF on the reaction pathways by measuring conversion and product selectivity. An application of this technology is in the area of hazardous waste remediation through combined SCF extraction of organics from the porous soil and solvent regeneration by oxidation. In lieu of this potential use of such systems, this work will involve the vanadium pentoxide (V2O5) catalyzed oxidation of 1,4-dichlorobenzene (a model compound for many hazardous materials) in both supercritical water and supercritical nitrous oxide (N2O).

流体在其临界点附近的独特性质可用于改变反应系统内的主要反应路径。 超临界流体 (SCF) 独特的溶剂特性可以促进传统溶剂无法实现的反应。 发生这种情况是因为超临界溶剂提供了一个环境，其中由于溶剂的物理性质（介于气体和液体之间）而消除了传质限制​​。 因此，相对于气体的高溶剂密度与相对于液体中的扩散率的高溶质扩散率相结合，创造了一种环境，其中高浓度的溶质可以溶解在溶液中，但不存在严格的传质限制。 该研究项目的目标是研究 SCF 溶剂对控制催化反应总体速率的速率过程的影响。 具体来说，PI 将尝试测量超临界条件下催化剂的吸附速率、颗粒内扩散速率和吸附能力。 他将使用色谱技术在各种实验条件下测量所需的速率参数，并通过测量转化率和产物选择性来考虑 SCF 对反应路径的总体影响。 该技术的一个应用是通过结合 SCF 从多孔土壤中提取有机物和通过氧化再生溶剂来修复危险废物。 这项工作将涉及在超临界水和超临界一氧化二氮 (N2O) 中用五氧化二钒 (V2O5) 催化氧化 1,4-二氯苯（许多危险材料的模型化合物），以代替此类系统的潜在用途。