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Catalytic and physicochemical properties of modified natural clinoptilolite

“…A large choice of acidic catalysts, such as oxides treated with acids [14,15], modified zeolites [10,13,[16][17][18][19][20], activated clays [21] and heteropoly acids [22,23] have been suggested in the literature for the isomerization of ␣-pinene. On the other hand, basic catalysts (e.g., alkaline earth-metal oxides) have been reported for the isomerization of ␣-to ␤-pinene [24].…”

Liquid phase transformation of α-pinene over Beta zeolites containing aluminium or boron, titanium and vanadium as lattice ions

“…Mono-, bi-and triocyclic products are formed as a result of the isomerization of a-pinene in presence of acid catalysts, in parallel and irreversible steps. Many heterogeneous catalysts such as titanium dioxide, clays, halloysite, natural and synthetic zeolites, activated carbon, silica-supported rare earth oxides and sulphated zirconia are examined for a-pinene isomerization [1][2][3]. In our previous studies, liquid phase isomerization of a-pinene has been investigated over clinoptilolite based natural zeolites, which is the most abundant deposits occurred at Western Anatolia region of Turkey and over natural clays (nonswelling montmorillonite) [1,4,5].…”

ZrO2–SiO2 Mixed Oxides Xerogel and Aerogel as Solid Acid Catalysts for Solvent Free Isomerization of α-Pinene and Dehydration of 4-Methyl-2-Pentanol

“…The selectivity of various products strongly depends on the structural, textural and catalytic features of the catalyst along with the reaction conditions [18,19]. Various solid acid catalysts such as zeolites, clays, zirconia and sulfated zirconia have been studied for the isomerization of a-pinene [20][21][22][23][24][25]. However, the selective isomerization of a-pinene to the desired isomers is still required.…”