| Autor: |
Devendra K. Sharma, Raghunath P. Mehrotra, Pratap Kumar Sinhamahapatra |
| Rok vydání: |
1978 |
| Předmět: |
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| Zdroj: |
Journal of Chemical Technology and Biotechnology. 28:740-744 |
| ISSN: |
0142-0356 |
| DOI: |
10.1002/jctb.5700281108 |
| Popis: |
The surface acidic strength distribution in a series of silica-alumina catalysts prepared by coprecipitation and stepwise precipitation techniques has been measured by the butylamine adsorption method. The amount of silica in the finished catalysts ranged from 86.0 to 96.9%. A linear relationship between the pH of the final gel (i.e. pH values of the solution in equilibrium with the gel material before washing) and X[=Al2O3/(SiO2+Al2O3)] was observed up to a certain level of pH; for coprecipitated catalysts it was 6.0 whereas for those precipitated stepwise the limit of pH was 7.0. Coprecipitated silica-aluminas were more enriched with weak acid sites or Bronsted sites (pKa = +6.8) and their concentration reached a maximum at about 87% silica. Stepwise precipitated silica-aluminas, on the other hand, have a greater population of strong acid sites, thus making them useful for cracking reactions. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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