Pore Characteristics and Acid Properties of Hierarchical SAPO-34
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- Institutt for kjemi 
This thesis investigates the pore connectivity and acid properties of the hierarchical SAPO 34 molecular sieve. The hierarchical version of the SAPO 34 molecular sieve was synthesized using the dry gel conversion as described by Yang et al. . The newly synthesized hierarchical sieve and its conventional counterpart, as synthesized at NTNU by Trygve Jakobsen , were compared through different methods of characterization: XRD, BET, FTIR and TPD, and by testing their efficiency in different reactions: the oligomerization of propene, the hydroxylation of phenol and the methanol to hydrocarbons (MTH) reaction. By BET measurements, the hierarchical SAPO 34 was found to contain micropores and mesopores at volumes of 0.155 cm3/g and 0.135 cm3/g respectively while the conventional SAPO 34 contained mostly micropores and some mesopores at volumes of 0.218 cm3/g and 0.003 cm3/g respectively. The pore connectivity investigations were inconclusive and possible explanations for this are provided as well as suggestions for further studies. Although the hierarchical SAPO 34 was found to have a smaller amount of acid sites than the conventional SAPO 34, the acid strength of the two samples was found to be similar. Furthermore, the product distributions from the employed reactions indicated the absence of acid sites in the mesopores of the hierarchical SAPO 34.