The present study is of great importance both from industrial application side and from fundamental point of view. The work considers ecologically significant industrial processe - utilization of chlorinated hydrocarbons. Particularly, 1,2-dichloroethane utilization is chosen as a model reaction to study the kinetics of hydrogenation process in fixed batch flow reactor over Pt-Cu silica supported bimetallic catalysts. The fundamental part of the study includes correlation search between kinetics performance and electronic-structural properties of Pt-Cu bimetallic catalyst. Establishing correlation between electronic-structural properties and performance in chemical reactions are of prime significance for understanding of chemical nature of particular chemical systems. The understanding means the ability to govern the process that is of huge interest for industrial applications.
The kinetic performance is determined directly by testing the selected catalyst in fixed bed reactor. The main characteristics derived from kinetics testing that are interesting for current study - selectivity and activity. The product of interest for presented process is ethylene, C2H4. The electronic-structural properties were derived mainly from the infrared-red (FTIR) study of carbon monoxide (CO) test molecule. The correlation between electronic-structural properties and kinetics performance are related to freshly pretreated catalyst.
It was established that the selectivity toward C2H4 is a strong function of Cu/Pt atomic ratio that depends on the size of Pt ensembles: the smaller the size of Pt ensembles the higher selectivity toward C2H4. Activity slightly decreases as Cu/Pt ratio is increasing. The observed kinetics performance is rationalized based on knowledge derived from FTIR study and knowledge from previously published works.
Structural sensitivity of C-Cl bond cleavage reaction is established for 1,2-dichloroethane hydrodechlorination. Elementary step of C-Cl bond cleavage is require 2-6 platinum atoms. Besides, the role of Cu as a main component responsible for C2H4 formation is shown experimentally. The structural dependence is rationalized in terms of ensemble size effect.
The mechanism of 1,2-dichloroethane hydrodechlorination reaction for highly selective catalysts is explained in terms of independent role of Pt and Cu.
Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-02222006-001930 |
Date | 02 June 2006 |
Creators | Kazachkin, Dmitry V. |
Contributors | Götz Veser, Assistant Professor, Department of Chemical and Petroleum Engineering, J. Karl Johnson, Professor, Department of Chemical and Petroleum Engineering, Radisav D. Vidic, Professor, Department of Civil and Environmental Engineering |
Publisher | University of Pittsburgh |
Source Sets | University of Pittsburgh |
Language | English |
Detected Language | English |
Type | text |
Format | application/pdf |
Source | http://etd.library.pitt.edu/ETD/available/etd-02222006-001930/ |
Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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