PERFORMANCE OF ACIDIC MCM-LIKE ALUMINOSILICATE CATALYSTS IN PYROLYSIS OF POLYPROPYLENE

Abstract

Mesoporous aluminosilicate catalysts having different Al/Si ratios were synthesized following a hydrothermal synthesis route and using different aluminum sources, such as aluminum nitrate and aluminum isopropoxide. These mesoporous materials have high surface areas, in the range of 520–1001 m2/g, and exhibit Type IV nitrogen adsorption isotherms. EDS and 27Al MAS NMR results showed that aluminum was incorporated more effectively into the structure of the catalyst forming a tetrahedral framework when aluminum nitrate was used as the aluminum source. The activities of these catalysts in the polypropylene pyrolysis reaction were tested in a TGA apparatus. Results showed a marked reduction in the degradation temperature in the presence of aluminosilicate catalysts. The activation energy of degradation was 172 kJ/mole without any catalyst. However, using the mesoporous aluminosilicate catalysts synthesized by using aluminum nitrate as the aluminum source, activation energy of the degradation reaction decreased to values of about 24–28 kJ/mole.