Fresh and used alkali acetate (MOAc with M+ = Li+, Na+, K+, Cs+) promoted bimetallic PdAu catalysts were studied to investigate the impact of the alkali metal cations on the deactivation of the catalysts during vinyl acetate (VA) synthesis from ethene and acetic acid. Dynamic reordering of PdAu toward an active Pd1Au1 phase, a less active M2Pd2(OAC)(6) and inactive Pd-3(OAc)(6) complexes determines the overall activity. Decreasing deactivation from LiOAc to CsOAc promoted PdAu can be associated with the lower concentration of inactive Pd-3(OAc)(6) leached from the active PdAu particles and with the lower loss of Cs+ compared to Li+ during reaction. CsOAc binds most efficiently to Pd-3(OAc)(6) and forms active Cs2Pd2(OAc)(6), lowering the tendency to leach Cs+. Reduction of Pd in M2Pd2(OAc)(6) to a mixed "Pd/M+-O" adlayer on the bimetallic PdAu particles stabilized active Pd-0 on the PdAu surface maintaining the catalyst activity. Thus, increasing "Pd/M+-O" concentrations from LiOAc to CsOAc lower long-term deactivation of PdAu. (C) 2015 Elsevier Inc. All rights reserved.