Studies in molten chloroaluminates : A. Fischer-Tropsch synthesis using metallic dispersions, B. Infrared spectroelectrochemistry using attenuated total reflectance

Author

Scott Edward Walters

Date of Award

12-1983

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

Gleb Mamantov

Committee Members

Richard Pagni

Abstract

The Fischer-Tropsch activity of several metallic catalysts in molten chloroaluminates has been studied at relatively low pressures. Low conversions of C0 to alkanes were observed for Co, Fe, Ni, Pd, Pt, Ir, Rh and Re. No reaction was observed for W, Ta and the pure chloroaluminate melt. Methane was the major product formed using any of these heterogeneous catalysts. The most favorable product distribution for these metals was observed for Ni catalysts, since less than half of the products was CH₄.

The effect of aluminum on the Fischer-Tropsch activity of these metallic catalysts in molten chloroaluminates has also been studied. In all cases, the conversion of C0 was enhanced by the presence of aluminum. The magnitude of enhancement depended on the catalyst. Large enhancements were observed for Co, Ni and Fe catalysts, while only slight enhancements were observed for Pd, Pt and Re. Aluminum behaved as a reagent, and not as a catalyst, since C0 conversion varied with the amount of Al in the system. The effect of Al on product distribution was also largely dependent on the metal catalyst involved. Small amounts of Al increased the production of CH₄, relative to the other products for Co, Fe and Ni catalysts, while no clear pattern emerged for these catalysts, when larger amounts of Al were present.

The Iri₄(CO)₁₂ catalyst precursor was also studied in chloroaluminate melts. In batch reactions at relatively long times, a slight excess of CH₄ over C₂H₆ was found. No CH₃CI was detected. In a recycle-flow reactor, C₂H₆ was produced in greater amounts than CH₄. CH₃CI was observed in the flow system. Enhancement by Al was found to be greater for small amounts of Al than for large amounts. The proportion of CH₄ in the products was observed to increase with increasing Al content.

An infrared spectroelectrochemical cell, based on attenuated total reflectance using a silicon crystal, has been developed for use in molten chloroaluminates. Spectra of chloranil and its reduction products have been obtained.

Recommended Citation

Walters, Scott Edward, "Studies in molten chloroaluminates : A. Fischer-Tropsch synthesis using metallic dispersions, B. Infrared spectroelectrochemistry using attenuated total reflectance. " PhD diss., University of Tennessee, 1983.
https://trace.tennessee.edu/utk_graddiss/13159