New catalysts have been developed by combining Pd-based bimetallic catalysts and zeolite supports to achieve higher selectivity for the selective hydrogenation of acetylene in a stream containing excess ethylene at relatively low temperatures (300-339K). Low-temperature hydrogenation offers the opportunity of using competitive adsorption to achieve preferential hydrogenation of acetylene. Previous work for this has found that bimetallic catalysts favor low temperature hydrogenation. Results from many other groups have also shown that Pd is a good catalyst for the selective hydrogenation of alkynes in excess ethylene. Therefore the strategy of the present work was to modify Pd catalysts and embed bimetallic particles in an environment that is highly selective for acetylene hydrogenation. Cation-pi interaction offers the potential for selective adsorption of acetylene. We used the ion-exchanged zeolite for the support of the bimetallic catalysts. The zeolite structure should have multiple dimensions and contain large pores, in order to house the bimetallic particles inside the pores. In this work, we focus on beta-type zeolites. Flow reactor studies using GC, batch reactor studies using FTIR, and TPR evaluation have been utilized for this project. It was found that the Pd-Ag bimetallic catalyst had a much higher selectivity for acetylene hydrogenation in excess ethylene than either Pd or Ag, while the Pd-Ni bimetallic catalyst behaved similarly to the Pd catalyst. Modeling of reactions in FTIR also showed that there was a small difference in the rate constant and equilibrium constant of Pd/beta-zeolite and Pd-Ni/beta-zeolite. The zeolite support also exhibited enhanced activity for the low temperature hydrogenation of acetylene.

This thesis offers novel methods for catalyst and process design for the selective hydrogenation of acetylene and 1,3-butadiene. The author predicts the properties of supported Pd–Ni bimetallic catalysts using density functional theory (DFT) calculations and temperature-programmed desorption (TPD). The excellent correlation between model surfaces and supported catalysts demonstrates the feasibility of designing effective bimetallic catalysts for selective hydrogenation reactions. The author also proposes a method for designing non-precious metal catalysts to replace precious metals. She modifies the process of selective hydrogenation of acetylene by coupling the selective adsorption to the selective hydrogenation in the liquid phase, as a result of which the ethylene selectivity is greatly improved and heat transfer is greatly enhanced. Lastly, by analyzing the mechanism of liquid-phase hydrogenation, the author proposes a multi-stage slurry bed reactor for industrial applications.“/p>

Recent Advances in Science and Technology of Zeolites and Related Materials is a collection of oral and poster communications, presented during the 14th International Zeolite Conference (IZC). The conference was hosted by the Catalysis Society of South Africa. In the tradition of the IZC series, this Conference provides a forum for the presentation of new knowledge in the science and technology of zeolites and related materials. Papers presented cover a wide range of topics that include synthesis, structure determination, characterisation, modelling, and catalysis. This highly visual book is a must for readers looking to stay up-to-date on zeolite science. * This three-part volume provides valuable information on zeolites and related materials * Includes papers that cover topics such as structure determination, modelling and separation processes * Contains new and exciting developments in the field