Mechanism of hydrodenitrogenation adsorption of piperidine on reduced molybdenum catalysts

Diffuse reflectance ir spectroscopy of adsorbed piperidine was done to study the interaction of highly basic cyclic amines with OH on various surfaces. The silanol groups on pure silica do not interact strongly with piperidine, as shown by their inability to promote the exchange of deuterium from OD with hydrogen from piperidine. After supporting molybdena on such silica, however, the silanol groups associated with interfacial sites became more acidic and are able to exchange D with piperidine, which is also adsorbed more strongly. The OH groups on pure alumina do not interact with adsorbed piperidine because of their high basicity. Upon supporting molybdena, however, new acidity and probably new OH groups are generated that interact and exchange D with piperidine.