Selective aromatization of light paraffins on platinum-ion-exchanged gallium-silicate bifunctional catalysts

Aromatization of propane over MFI-gallosilicates

“…I. This is in accordance with results published earlier [ 15,17 ]. Upon measuring the conversions at different temperatures, some coke deposition on the catalyst could not be avoided.…”

Introduction of gallium in HZSM5 and HY zeolites by post-synthesis treatment with trimethylgallium

“…In the latter case, slightly lower conversions are measured ( fig. 6b), while the selectivity to aromatics increases sharply from 36 C% without gallium to 55 C% in the presence of gallium, which is similar to earlier observations on gallium impregnated HZSM5 zeolites and isomorphously substituted gallosilicates [7,8]. The high aromatics selectivities indicate that the gallium introduced in this way is active for molecular hydrogen formation.…”

“…The conversion of propane over HZSM5 zeolites containing gallium gives high yields of aromatics, which appeared to be independent of the preparation method [7,8]. Catalysts prepared by isomorphous substitution of aluminum by gallium in the HZSM5 zeolite, by impregnation of the HZSM5 zeolite with a gallium salt solution and subsequent calcination, or prepared by physically mixing GazO 3 powder with the HZSM5 zeolite, yielded comparable aromatics selectivities.…”

Aromatization ofn-butane over Ni-ZSM-5 and Cu-ZSM-5 zeolite catalysts prepared by using Ni and Cu impregnated silica, fiber

“…The authors in ref. [13] concluded that the reaction of propane aromatization over Ni-ZSM-5 catalysts was not selective and that the reaction of hydrogenolysis was predominant. However, our results for the reaction of n-butane aromatization showed that hydrogenolysis activity was decreased and dehydrogenation activity was increased over the Ni-ZSM-5 catalysts.…”

“…It has been reported by some authors that the state of Ni and Cu is dependent upon the methods of catalyst preparation, types of support, and modes of catalyst pretreatments [8,9]. The aromatization reactions reported over Ni and Cu-ZSM-5 zeolite catalysts are: ethene aromatization over Cu-ZSM-5 [10], hexane aromatization over Ni-ZSM-5 [11 ], pentane aromatization over Ni-ZSM-5 [12] and propane aromatization over Ni-ZSM-5 [13]. In this paper we have investigated the aromatization of n-butane over Ni-ZSM-5 and Cu-ZSM-5 catalysts prepared by using Ni and Cu impregnated silica fiber during the process of ZSM-5 zeolite synthesis.…”