Abstract
Catalytic transformation of n-heptane over H(4)SiW(12)O(40)center dot 13H(2)O as a solid acid catalyst was investigated. The prepared heteropolyacid H(4)SiW(12)O(40)center dot 13H(2)O was characterized by means of XRD and IR. Catalytic tests were carried out in a continuous flow system under atmospheric pressure. The effect of the reaction temperature and the support on the n-heptane transformation was investigated. It has been found that Bronsted acidic sites play an important role in n-heptane reaction. The lack of protons on the heteropolyacid owing to the collapse of the Keggin structure observed at 320 degrees C led to a decay of the activity of H(4)SiW(12)O(40)center dot 13H(2)O. The decrease of the number of protons through a heteropolyacid-support interaction favored the cracking reaction to the detriment of cyclization reaction.