With the addition of known impurities in the starting materials, several previously unobserved impurities were predicted for ibuprofen synthesis (Figure ). In R1, CH 3 COOH and H 2 O are known to be present in acetic anhydride, and hydrofluoric acid, respectively . Their presence resulted in two new impurities. For R2, we noted multiple carbonylated and oxidized impurities with the presence of CO, CO 2 , HCHO, and HCOOH in the H 2 gas. In R3, palladium (Pd) and CO contained several trace metal impurities and several other common gaseous impurities, leading to the production of several low-level impurities .