IRON OXIDE-IRON PHOSPHATES AS SOLID ACID CATALYSTS

A series of iron oxide-iron phosphate (FeFeP) catalysts with various Fe/P ratio were prepared with the coprecipitation method. The acidic properties of these catalysts were examined by temperature-programmed-desorption (TPD) of ammonia and the dehydration reaction of isopropanol. The reaction was carried out in a continuous flow microreactor at 120-230 ° C under atmospheric pressure. Alumina-aluminum phosphates (AAPs) were also included in this study. The results of TPD of ammonia indicated that the surface of FeFeP is weakly acidic and their strength are approximately the same. The dehydration activities of these catalysts are decreased with increasing the Fe/P ratios of the samples. Correlation between the reaction rates and the Fe/P ratios indicated that the addition of phosphorus enhanced the acidities of the catalysts. © 1990 J.C. Baltzer A.G. Scientific Publishing Company.