The Influence of Dopants on Copper Chloride Catalysts for Ethylene Oxychlorination Reaction
Appears in the following Collection
- Kjemisk institutt 
AbstractThe main aim of this Ph.D. project was to study, understand and improve the current knowledge on the Cu-based catalytic reaction in the conversion of ethylene-to-1,2-dichloroethane (oxychlorination), a crucial intermediate reaction to produce PVC (poly-vinyl chloride) plastic, a second largest commodity. The main concerns of the catalyst (Copper chloride supported on a porous alumina support) are loss of the catalyst (deactivation) and getting 100% desired product (selectivity). Deactivation of the catalyst and production of undesirable chlorinated by-products increase the overall costs of the PVC process and more importantly release high amount of environmentally polluted gases. So, study of this process has two main importances: Economical and environmental. We succeeded firstly in an improved fundamental knowledge about the catalytic system, there on developed a better efficient catalyst by adding selective foreign (technically called as dopants/promoters) metal chlorides. Besides that, the developed fundamental knowledge from this work helped our partner company “INEOS ChlorVinyls Scandinavia” to improve the performance of their industrial process, which had plants in Porsgrunn (Norway) and Stenungsund (Sweden). Copper chloride supported on alumina catalysts doped with other metal chlorides (potassium, caesium, lanthanum, magnesium, lithium and sodium chlorides) which are basically promote the reaction activity and selectivity were subjected to investigation in this work. Main emphasis has been given to study these materials i.e study their surfaces, bulks and the changes in their physical, chemical properties in a fresh material and also during the reaction. For this purpose, we adopted several experimental techniques such as synchrotron radiation techniques (X-rayabsorption spectroscopy, XAS), Infra-red spectroscopy (IR), Ultra-violet spectroscopy (UV), the reaction tests in the home-build reactor set up. The various parameters (such as surface composition, oxidation states (I and II) of copper, their relative fractions, chemical phases of the copper containing species and their red-ox behaviour etc.). By using these several complimentary technique we were able to study all these parameters, which are the main factors which influence the chemistry of the reaction. By studying these materials using XAS, we were able to investigate the how the copper oxidation states, its surroundings and its red-ox behaviour are changing during the reaction vs the dopant added. Investigated these materials using IR, and helped us to develop the better knowledge on how the surface (technically acidity and active sites) sites which are responsible for processing the reaction and also for producing some unwanted by-products, are modified by adding dopant. With this knowledge, we were able to control the speed of the process and also controlling the unwanted products. In short summary, this work developed very fruitful knowledge about the influence of foreign element on the catalytic property of the copper chlorides and in-turn helped to provide a scientific knowledge base for further improving not only this reaction, but also for other reactions which involves red-ox property of copper.
List of publications
Paper 3-5 are removed due to publisher restrictions.
Publication I: N. B. Muddada, U. Olsbye, G. Leofanti, D. Gianolio, F. Bonino, S. Bordiga, T. Fuglerud, S. Vidotto, A. Marsella, C. Lamberti, "Quantification of copper phases, their reducibility and dispersion in doped-CuCl2/Al2O3 catalysts for ethylene oxychlorination". Dalton Transactions, 2010, 39, 8437-8449. DOI: 10.1039/c0dt00488j
Publication II: N. B. Muddada, U. Olsbye, L. Caccialupi, F. Cavani, G. Leofanti, D. Gianolio, S. Bordiga, C. Lamberti, “Influence of additives in defining the active phase of the ethylene oxychlorination catalyst” Physical Chemistry Chemical Physics, 2010, 12, 5605-5618. DOI: 10.1039/b926502n
Publication III: D. Gianolio, N.B. Muddada, U. Olsbye, C. Lamberti, “Doped-CuCl2/Al2O3 catalysts for ethylene oxychlorination: influence of additives on the nature of active phase and reducibility”, Nuclear Instruments Methods Phys. Research B, 2012, 284, 53-57. DOI: 10.1016/j.nimb.2011.08.004
Publication IV: N. B. Muddada , U. Olsbye, T. Fuglerud, S. Vidotto, A. Marsella, S. Bordiga, D. Gianolio, G. Leofanti and C. Lamberti, "The role of chlorine and additives on the density and strength of Lewis and Brønsted acidic sites of gamma-Al2O3 support used in oxychlorination catalysis: a FTIR study", Journal of Catalysis, 2011, 284, 236–246. DOI: 10.1016/j.jcat.2011.08.014
Publication V (unpublished): Influence of dopants in controlling the by-products formation in ethylene oxychlorination reaction: site selective mechanistic details. N.B.Muddada, U.Olsbye, T. Fuglerud and C. Lamberti.