Linear hexane isomerization over the natural zeolite based catalysts depending on the zeolite phase composition

Superacids Based on Zirconium Dioxide

“…The conversion of n-C 6 at WO x /ZrO 2 (Pt) amounts to more than 82% with up to 87% selectivity in i-C 6 . Similar results at zeolite catalysts are obtained at higher temperatures [78,79]. The promotion of SO 4 2− /ZrO 2 (Pt) with iron, manganese [57,62,67], silicon [24,58,59], aluminum [63,67], and gallium [61,64] oxides leads to increase of the activity in isomerization.…”

“…Another mechanism proposes initial protonation of the alkane molecule with the participation of the strong B centers and the formation of carbonium ions containing a pentacoordinated carbon atom; the removal of two hydrogen atoms from this ion with the participation of Pt; isomerization of the carbenium ion through a cyclopropane transition state; addition of Hto the isomer and H + to the deprotonated B center [55]. A more detailed mechanism, which supposes b-cleavage of the carbenium ion with participation of the L centers, was proposed in [79,80]. Isomerization of n-alkanes at sulfated zirconium dioxide can take place, as already mentioned, with the participation of strong L centers, which abstract a hydride ion from the hydrocarbon molecule [3,4].…”

The kinetics of citral hydrogenation over Pd supported on clinoptilolite rich natural zeolite

“…In present study, Clinoptilolite rich natural zeolite was chosen as a catalyst support to investigate how it affects the Pd catalyst activity and selectivity. Some of the reactions catalysed by the natural clinoptilolite supported catalysts are the isomerization of linear hexane [17] oxidation of m-xylene [18] and the isomerization of a-pinene [19].…”

Influence of organic cations sorption on the point of zero charge of natural zeolite

“…Prirodni zeoliti se koriste kao: katalizatori u mnogim hemijskim reakcijama, molekulska sita i katjonski izmenjivači [5][6][7]. Osobina katjonske izmene je iskorišćena za primenu zeolita kao sorbenta za amonijak i toksične metale, koji su prisutni u otpadnim vodama [8,9].…”