High-throughput primary synthesis and screening methods have been applied to the heterogeneously-catalyzed gas phase oxidation of ethane to acetic acid using mixed metal oxide catalysts. The discovery libraries consisted of 16 x 16 arrays of 256 catalysts on 3" x 3" quartz wafers. Catalysts were prepared using automated liquid-dispensing techniques and screened in parallel for catalytic activity in a Symyx Technologies 256-channel microfluidic reactor. Product detection was performed using parallel colorimetric techniques on products adsorbed on silica-coated glass TLC plates. This workflow allows the screening of more than 3000 samples per day. Promising leads were confirmed in focus libraries and are being optimized in secondary screening. MoV was identified as the most active binary of redox metals and was subsequently doped with main group, rare earth, and transition metals to form ternaries. Prior art MoVX (X = Nb, Ni, Sb) catalysts were successfully reproduced and it was shown that Pd doping significantly increases the catalytic activity of these systems. Three novel MoVY ternary systems were discovered. (C) 2003 Elsevier Science B.V All rights reserved.