FT-IR STUDY ON THE ADSORPTION OF BENZOIC-ACID AND ITS DERIVATIVES ON TRANSITION-METAL OXIDES

The present study gives the results of our attempts to gain more knowl edge on the interaction between an aromatic carboxylic acid and an oxi de catalyst. There is quite a difference in the coordination of benzoi c (and salicylic) acid with an acid-base catalyst (gamma-Al2O3) or a r edox one (alpha-Mn3O4). When a substituent is incorporated into the ri ng, the difference becomes even larger. These differences can perhaps explain the difficulties in the catalytic reduction from (substituted) benzoic acids to the corresponding aldehydes.