Date of Award

1998

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemical Engineering

First Advisor

Geoffrey L. Price

Abstract

Copper-containing zeolites have been prepared by vapor, aqueous, and solid-state ion-exchange, characterized, and investigated for the conversion of light amines. A copper-containing zeolite was synthesized by vapor ion-exchange in this study by a method that does not appear to have been previously reported. This material was prepared by reaction of the acidic zeolite with CuCl vapor, followed by oxidation of the Cu+ ions to copper oxonium. ions which are converted to copper hydroxyl dimers on exposure to air. The copper hydroxyl dimer exchanged zeolite is stable in air and can be converted back to a highly exchanged Cu+ zeolite by either partial hydrogen reduction or thermal treatment in an inert environment. Aqueous ion-exchanged MFI and BEA have also been prepared and investigated. These investigations indicated that, as with the vapor ion-exchanged materials, most of the copper ions in the aqueous ion-exchanged materials existed as copper hydroxyl ions but in lower loadings than we were able to achieve using the vapor ion-exchange technique. The solid-state ion-exchange of CuO and Cu2O with acidic MFI was also investigated. The results in this study suggested that CuO reacts with the zeolite on thermal treatment according to form zeolite coordinated Cu2+. During this process, some of the CuO is converted into an unreducible species such as copper metal or copper aluminates. The results obtained suggested that under 1-propanamine reaction conditions, all of the copper ions in the zeolites were reduced to copper metal by the reactant, with regeneration of the zeolitic acid sites. Both the copper content and the dispersion of the copper metal play a significant role in the rate of conversion of 1-propanamine and the distribution of products produced. The acid sites in these materials catalyze the condensation of the primary amine reactant to secondary amines and ammonia. Dispersed copper metal catalyzes the selective dehydrogenation of the secondary amine to produce imines. The presence of copper clusters with two or more copper atoms further catalyzes the dehydrogenation of the imines to nitriles.

ISBN

9780599213715

Pages

165

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