Physicochemical and Catalytic Properties of SAPO-31 Materials Prepared from the Silica Sources Characterized by a Different Degree of Polymerization
Russian Chemical Bulletin
, E-ISSN: 1573-9171
||fumed silica, isomerization, mechanism of silicon incorporation, microporous silicoaluminophosphates, n-decane, tetraethoxysilane
G. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
5 prosp. Akad. Lavrentieva, 630090 Novosibirsk, Russian Federation.
Novosibirsk State University, 2 ul. Pirogova, 630090 Novosibirsk, Russian Federation.
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences,
18 ul. Kutateladze, 630128 Novosibirsk, Russian Federation
Research Institute of Inorganic Chemistry, RENTECHUniCRE, Areal Chempark, Zaluzi, 436 70 Litvinov, Czech Republic.
Two series of microporous silicoaluminophosphates SAPO-31 with different Si content (Si/Al = 0—0.5) were synthesized using silica sources characterized by various degree of polymerization (fumed silica and tetraethoxysilane). Physicochemical properties of the resulted materials were studied by X-ray diffraction, XPS, scanning (SEM) and transmission (TEM) electron microscopy. The nature of the silicon species was identified by 29Si NMR method and the acidity was measured by IR-spectroscopy of adsorbed pyridine. The activity and selectivity of Pd modified SAPO-31 samples from both series were evaluated in the isomerization of n-decane. It was found that the use of the monomer as a silicon source ensured more efficient silicon incorporation, which resulted in the higher activity of Pd/SAPO-31 catalysts. Moreover, the selectivity of these samples for isomerization was found to be independent of the silicon content and its distribution.