IDENTIFICATION OF ADSORPTION FORMS BY IR SPECTROSCOPY FOR FORMALDEHYDE AND FORMIC-ACID ON K3PMO12O40

Interaction of HCOOH and H2CO with K3PMo12O40 has been studied by IR s pectroscopy. HCOOH adsorbed mainly in molecular form due to hydrogen b onds with surface oxygen ions. Two forms of adsorbed H2CO were observe d depending on the pressure. At low pressures it adsorbed on Bronsted acid sites with the formation of hydrogen-bonded complexes. Dioxymethy lene groups and a small amount of polyoxymethylene groups were formed at higher pressures. In contrast to oxide catalysts, formates were for med only in small amounts iu the absence of oxygen. This can be explai ned by the formation of new surface adsorption sites - Mo ions - due t o a partial reduction of K3PMo12O40 during its interaction with HCOOH and H2CO.