Physicochemical and catalytic properties of SAPO-31 materials prepared from the silica sources characterized by a different degree of polymerization

• Published in: Russian chemical bulletin Vol. 66; no. 2; pp. 231 - 240
• Main Authors: Smirnova, M. Yu, Davydova, M. G., Titkov, A. I., Ayupov, A. B., Kikhtyanin, O. V.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2017; Springer Nature B.V
• Subjects: Aluminum; Catalysis; Chemical synthesis; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Degree of polymerization; Full Articles; Infrared spectroscopy; Inorganic Chemistry; Isomerization; Materials selection; NMR; Nuclear magnetic resonance; Organic Chemistry; Polymerization; Scanning electron microscopy; Selectivity; Silica fume; Silicoaluminophosphates; Silicon; Silicon dioxide; Spectroscopic analysis; Tetraethyl orthosilicate; Transmission electron microscopy; X ray photoelectron spectroscopy; X-ray diffraction; mechanism of silicon incorporation; tetraethoxysilane; n-decane; microporous silicoaluminophosphates; fumed silica; isomerization
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-017-1723-x

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 29 Si 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.