Growth and optimization of metal-substituted porous aluminophosphates for catalytic applications

Abstract

A number of monometallic and bimetallic aluminophosphate materials were synthesized by isomorphous substitution of iron (III), cobalt (II), and magnesium (II) for Al+3, and silicon (IV) replacing both Al+3 and P+5. By replacing either Al +3 or P+5 in the ordered microporous aluminophosphate AlPO4-5, a series of active sites are created and the potential for catalytic application as solid acid is created. The monometallic and bimetallic AFI materials were synthesized by the hydrothermal method and produced pure, highly crystalline microporous catalysts which properties not seen in other aluminophosphates. These catalysts were characterized by different techniques including powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption methods. Changes in the structural unit cell parameters were observed when one or two metals were introduced in the structural framework. This stands as evidence of the successful incorporation of these metals in the AFI framework. Synthesized catalysts were tested for the Liquid phase esterification reaction using acetic acid and ethanol to produce ethyl acetate. Currently catalyzed by toxic and hazardous catalyst, the esterification of acetic acid with metal substituted catalysts provides a more environmentally favorable solution. The substitution of silicon to replace both aluminum and phosphorus ions clearly creates a large number of active sites and provides an enhanced catalytic performance for esterification. This monometallic and bimetallic substitution provides an important alternative approach to synthesize acid catalysts for different industrial applications.

Date of Award	2016
Original language	American English