Acid and catalytic properties of new thermostable sulfocationic exchangers supported on aluminosilicates

Abstract

The acid properties of supported polyphenylketone and sulfopolyphenylketone were followed by quantitative IR studies of ammonia and pyridine adsorption. The deposition of polyphenylketone decreased the concentration of Brønsted acid sites and also diminished the intensity of IR band of silanol (Si–OH) groups, due to partial covering of aluminosilicate surface by polymer. Sulfonation of supported polyphenylketone (by H 2SO 4 treatment) resulted in a distinct increase of Brønsted acidity, because of SO 3H groups insertion. The amount of new protonic sites was lower than the amount of sulfur atoms inserted by sulfonation, which indicated that not all sulfur atoms took part of acidic SO 3H groups. The conversion in 2-propanol dehydration showed the same trends as the Brønsted acidity of the samples. The dehydration activity of aluminosilicate supports decreased upon polyphenylketone deposition and distinctly increased upon sulfonation. 2-Propanol dehydration produced propene and diisopropyl ether (DIPE). The selectivity of supports towards DIPE was 31–48%. It increased upon polyphenylketone deposition and sulfonation (to 65–77%). Supported sulfopolyphenylketone may be efficient catalysts for the production of DIPE (which may be high octane, oxygen containing additive to fuels). The advantage of supported sulfopolyphenylketones, comparing with unsupported acidic cationites (e.g. sulfonated styrene-divinylbenzene copolymers) are: possibility of formation of big grains, large surface area, high thermal and mechanical stability, as well as not swelling in reaction media.