Degree Type

Dissertation

Date of Award

2003

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

Robert J. Angelici

Abstract

The ability of Ru(NH3)5(H2O) 2+ to bind to thiophenes has been used in an extraction process in which a solution of Ru(NH3)5(H2O) 2+ in 70% DMF and 30% H2O is contacted with a simulated petroleum feedstock (45% toluene/55% hexanes) containing 400 ppm of DBT. Five successive extractions reduce the amount of DBT in the simulated feedstock from 400 ppm to 25 ppm. The Ru(NH3)5(H2O) 2+ extractant can be regenerated from the Ru(NH3) 5(DBT)2+ either by air-oxidation followed by H2-reduction or by displacement of the DBT by adding H2O to the DMF/H2 O phase.;Complexes CpRu(CO)2(BF4) and CpFe(CO)2(THF) 2+ were adsorbed onto a mesoporous silica substrate. When these modified silica surfaces are stirred with a simulated gasoline feedstock containing 400 ppm(S) DBT, they form CpRu(CO)2(DBT)+ and CpFe(CO) 2(DBT)+ on the silica surface and lower DBT levels by 98% and 70% respectively, as determined by GC. These metal-complex modified surfaces behave as solid phase extractants (SPEs) towards sulfur impurities in gasoline and diesel fuels. The surface metal-DBT complexes, have been characterized by CP MAS 13C NMR and XPS. Through their independent synthesis, the X-ray structures of CpRu(CO)2(DBT)+ and CpFe(CO) 2(DBT)+ were solved.;Finally, we report the use of solid phase extractants (SPE) consisting of Ag+ salts (SPE-Ag) adsorbed on mesoporus SBA-15 or amorphous silica for the removal of DBT and 4,6-Me2DBT from a simulated diesel feedstocks. In these extractions SPE-Ag was stirred with DBT in decanes. It was observed that within 1 min, the DBT level was reduced from 400 ppm to 72 (+/-9) ppm, while 4,6-Me2DBT was reduced to 75 (+/-6) ppm. The active SPE-Ag may be regenerated by washing with diethylether, thereby separating the DBT from the petroleum feedstocks. The easy regeneration of these adsorbents makes them attractive for the deep desulfurization of petroleum feedstocks.

DOI

https://doi.org/10.31274/rtd-180813-168

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu

Copyright Owner

Scott Groh McKinley

Language

en

Proquest ID

AAI3105092

File Format

application/pdf

File Size

73 pages

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