Interaction of the hydroxyl groups of the zeolitic support with the P-V-O active component in a redox catalyst

The results of the measurements of the concn. changes of structural OH groups or electron acceptor centers of the following types of zeolitic catalysts are given: (1) an HY zeolite either with the supported active component P-V-O (P/V = 1) or with a component contg. only either V or P in concns. corresponding to the active component P-V-O; (2) a zeolite HZSM-11 with the supported active component P-V-O. The latter catalyst, in contrast to the catalysts based on HY zeolite, makes it possible to oxidize butadiene to maleic anhydride and not only to furan. The changes of the OH group concns. were detd. by measuring the changes in the absorbances of the stretching vibration bands of the structural OH groups and by measuring the changes of the initial reaction rates of ethylene oligomerization. The difference in the selective oxidn. of butadiene is caused by interaction of the OH groups of the supporting HY zeolite localized in the large cavities of its skeleton with both P and V present in the active component P-V-O. In the case of the zeolitic catalyst HZSM-11 supporting the same active component, no such interaction was found; explaining the different catalytic behavior of zeolitic catalysts (1) and (2). [on SciFinder(R)]