OP-II-3

PP-I-4TIOxygen InjectorPITIPIProduct ContainerAcetic AcidContainer(Evaporator)ReactorTIPIPITIHeat ExchangerFig. 1. A schematic of the vinyl acetate pilot reactor instrument3. Results and ConclusionsThe experiments showed that the reaction rate of producing vinyl acetate inpresence of Pd-Au catalysts, without implementing promoters can be very slow, thus noteconomically efficient. However in contrast, metallic promoters increase the reactionrate, eventually increasing the conversion and the selectivity of the reaction by creatingan acid layer on the catalyst bed. The acetate salts of alkaline metals such as lithium,sodium and potassium increases the reaction rate significantly while the effect isincreased from the top to the bottom of the alkali metals column in the periodic table. Toexplain this behavior, one can refer to the effect of the common ion. The common ionthat is achieved from the dissociation of acetate salts in compounds available on thecatalyst bed; improving adhesion of the acetic acid molecules to the catalyst surface,thus producing the mediator material Pd(CH 3 CO), which is the main mediator in theproduction reaction of vinyl acetate on the catalyst bed.References[1]. S. Nakamura, T. Yasui, “The mechanism of the palladium-catalyzed synthesis of vinyl acetatefrom ethylene in a heterogeneous gas reaction”, J. Catal., 17, (1970), 366.[2]. B. Samanos, P. Boutry, R. Montarnal, “The mechanism of vinyl acetate formation by gas-phasecatalytic ethylene acetoxidation”, J. Catal., 23 (1971), 19.[3]. A.H. Zaidi, “Catalytic activity of supported liquid-phase lithium—palladium acetate catalysts in theoxidation of ethylene to vinyl acetate”, Appl. Catal., 30 (1987), 131.[4]. Y.F. Han, J.H. Wang, D. Kumar, Z. Yan, D.W. Goodman, "A kinetic study of vinyl acetatesynthesis over Pd-Au/Sio2 and Pd/Sio2 catalysts". J. Catal, 232, pp. 467-475 (2005).226