FOOTPRINT CATALYSIS .7. REINVESTIGATION OF THE IMPRINTING PROCEDURES FOR MOLECULAR FOOTPRINT CATALYTIC CAVITIES - THE EFFECTS OF IMPRINTINGPROCEDURE TEMPERATURE ON THE CATALYTIC CHARACTERISTICS

The authors' imprinting procedures for ''molecular footprint'' catalyt ic cavities on a silica (alumina) gel surface were reinvestigated. The increases of temperature during the incorporation of aluminum ions in to the silicate matrix and during the footprint-imprinting with a temp late remarkably affected the catalytic characteristics of the resultin g cavities. A change from room temperature to 75-80-degrees-C increase d the catalytic specificities (k(cat)/K(m)) by a factor of nearly 50. The results also provided experimental proof for the speculated mechan ism of footprint formation. That is, the imprinting comprises preceden t Lewis acid site generation on a silicate and subsequent Lewis acid-t emplate complexation. The resulting acid-template complexes give rise to the footprint cavities upon removal of the template.