GOALI: Characterization of Active Sites in Zeolites for Hydrocarbon Cracking Reaction

中文摘要 本文研究了烃类裂解用沸石催化剂的活性中心。 蒸汽处理的HY沸石中的强布朗斯台德位点通过用胺如吡啶毒化，然后通过甲硅烷基化封闭未毒化的（较弱的）羟基位点来分离。 然后，对强位点的仔细再生使它们能够与弱位点分开研究。 这是使用核磁共振，红外光谱，和微量热吸附的基本探针分子。 设计了一组单独的实验来探索骨架外阳离子对催化活性和羟基性质的影响。 骨架外铝、镓或镧离子通过沸石羟基与气相中引入的金属的氯化物或烷基反应而引入到HZSM-5中。 随后的水解得到分散的骨架外物质，其特征在于结构，阳离子位置和催化活性。 烃类裂解是由原油生产汽油的关键步骤。 虽然已经确定HY沸石的蒸汽处理会产生非常活性的裂化催化剂，但导致这种情况的因素仍然是神秘的。 这项研究是一种尝试，以确定和隔离那些网站负责的催化活性，并研究它们的相互作用与extraframework物质在沸石基质。 这是西北大学和阿莫科石油公司之间的合作研究成果。 ***

ABSTRACT Harold Kung This is an investigation of the active sites in zeolite catalysts used for cracking of hydrocarbons. Strong Bronsted sites in steamed HY zeolites are isolated by poisoning with an amine such as pyridine and then blocking the unpoisoned (weaker) hydroxyl sites by silylation. Careful regeneration of the strong sites then allows them to be studied separately from the weaker sites. This is done using nuclear magnetic resonance, infrared spectroscopy, and microcalorimetry of adsorption of basic probe molecules. A separate set of experiments is designed to explore the effects of extraframework cations on catalytic activity and hydroxyl-group properties. Extraframework aluminum, gallium, or lanthanum ions are introduced into HZSM-5 by reacting the zeolite hydroxyl groups with the chloride or alkyl of the metal introduced in the gas phase. Subsequent hydrolysis gives dispersed extraframework species that can be characterized for structure, cation location, and catalytic activity. Hydrocarbon cracking is a crucial step in the production of gasoline from crude oil. Although it is well established that steaming of HY zeolite results in a very active cracking catalyst, the factors responsible for this remain mysterious. This study is an attempt to identify and to isolate those sites that are responsible for the catalytic activity and to study their interactions with extraframework matter in the zeolite matrix. This is a collaborative research effort between Northwestern University and Amoco Oil Company. ***