CHARACTERIZATION OF THE ACIDIC AND BASIC PROPERTIES OF ALPHA-LIALO2, GAMMA-LIALO2, AND CALCINED HALO2 USING ISOPROPYL-ALCOHOL

Characterization of both the acidic and basic sites of alphaLiAlO2, ga mmaLiAlO2, and calcined ''HAlO2'' was carried out with the isopropyl a lcohol probe reaction. All three materials catalyzed the formation of both propylene and acetone. The formation of propylene is indicative o f acidic-basic pair sites, while the presence of acetone is indicative of basic sites. In addition to the formation of both propylene and ac etone, base-catalyzed acetone aldol condensation products were formed on both alphaLiAlO2 and calcined ''HAlO2.'' Both materials produced a C6DIENE (2-methyl-1,3-pentadiene or 4-methyl-1,3-pentadiene) aldol con densation product, while alphaLiAlO2 also produced the aldol condensat ion products 4M2PONE (4-methyl-2-pentanone) and 4M2POL (4-methyl-2-pen tanol). The reaction pathways that describe the formation of the vario us C6 products were used to infer the nature of the basic sites on the materials. Additional information obtained from TPD and FTIR of chemi sorbed CO2 demonstrate that the basic sites on alphaLiAlO2 are similar in strength and number to MgO. (C) 1994 Academic Press, Inc.