The chemical 1,3-butadiene (BD) is usually produced from ethanol and acetaldehyde (ethanol to BD, ETB) over Ta2O5/SiO2 catalyst in fixed-bed system. However, the ETB process has a short catalyst-regeneration cycle due to rapid deactivation of the catalyst by coke. To overcome this problem, a circulating fluidized-bed (CFB) reactor could be used in the ETB reaction for continuous regeneration of deactivated catalyst. The catalyst supplied to a CFB reactor must be spherical, show good catalytic performance, and be mechanically strong. In this study, a series of samples of Ta2O5 catalyst on silica spheres with different pore and particle sizes, were prepared. The catalysts were examined for mechanical strength by an attrition test and in ETB reaction in the fixed-bed reactor. The Ta2O5/Q-6 catalyst, with particles size of 75-150 mu m, showed good mechanical strength and the best catalytic performance. This optimum spherical catalyst was tested to examine its hydrodynamic properties in a cold-bed CFB reactor. (C) 2014 Elsevier B.V. All rights reserved.