Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Polish Journal of Chemistry

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Sol-gel Synthesis and Characterization of ZrO2-SiO2 Mixed Oxides

Viter V. N.

Polish Journal of Chemistry

2009

Vol. 83, nr 9

1515-1522

A simple and convenient sol-gel method for preparation of ZrO2-SiO2 mixed oxides (10–60 mol. % zirconia) has been developed. Tetraethylorthosilicate and zirconium oxychloride were used as starting materials. The obtained mixed oxides have specific surface ar eas of 140–630 m2/g. High de grees of xerogels ho mo ge ne ity were con firmed by XRD, and FT-IR methods as well as surface acidity studies. The strength of acid sites corresponds to an H0 value between –8.2 and –10.10. The sample with 33 mol. per cent ZrO2 showed the maximum acidity. .

Synthesis and Characterization of Solid Acid in System SnO2/B2O3

Viter V. N., Nagorny P. G.

Polish Journal of Chemistry

2008

Vol. 82, nr 11

2081-2087

SnO2/B2O3 materials with Sn/B molar ratio 1:1; 1:2 and 1:3 were synthesized from SnCl4, H3BO3 and (NH2)2CO. The samples contain SnO2 with different cristallinity and anamorphous borate phase. Their thermal transformations were investigated by DTA method. The surface acidity was investigated by TPR method using conversion of 2-methyl-3-butyn-2-ol (MBOH). The temperature maximum of MBOH dehydration for SnO2/B2O3 materials is close to that for ZrO2/SiO2 catalyst. On the surface of SnO2/B2O3 mainly strong acid sites were detected. In the case of B2O3/SiO2 (aerosil), samples have mainly weak acid sites. The surface of pure SnO2 has amphoteric sites. IR spectroscopy and MAS NMR spectra of 11B showed that SnO2/B2O3 materials had three- and four-coordinated B atoms.