An investigation on the formation of an effective activity layer by acetylene penetration in copper-bismuth catalyst with spherical silica gel as supporter was conducted in connection with butynediol synthesis. Employing Weisz-Prater Criterion

it was proved that

within the scope of our experimental conditions

acetylene was the key component in the bicomponent in-trapellet diffusion control system. Since acetylene showed zero order in intrinsic reaction kinetics

according to the criterion value 2A

valuable conclusions were drawn by comparing uniformed distributed copper with egg-shell and multilayer distributed catalyst pellets.