Synthesis and Characterization of Basic Catalysts Based on Sodium-Magnesium Mixed Phosphates and Their Use in the Conversion of 2-Hexanol.

Various catalysts consisting of sodium-magnesium mixed orthophosphates were synthesized and characterized in structural terms using X-ray diffraction, thermogravimetric analysis, differential thermal analysis, diffuse reflectance infrared spectroscopy, and solid-state (31)P NMR spectroscopy. In addition, the surface properties of the solids were determined from N(2) adsorption-desorption isotherms and their chemical properties characterized with various titrants. One of the solids obtained consists of NaMgPO(4)/Mg(2)P(2)O(7) and the rest of NaMgPO(4)/MgO. Their surface chemical properties vary depending on the particular synthetic procedure used; thus, the NaMgPO(4)/MgO systems exhibit similar populations of acid and basic sites, whereas the NaMgPO(4)/Mg(2)P(2)O(7) systems contain many more acid sites than basic sites. All the solids obtained exhibit substantial dehydrogenating activity in the conversion of gaseous 2-hexanol; in fact, some of the NaMgPO(4)/MgO systems are even more active and selective than a MgO solid tested under identical reaction conditions. Copyright 2001 Academic Press.