Influence of the Brønsted Acidity on the Ring Opening of Decalin for Pt-USY Catalysts.

Abstract

A challenging hot topic faced by the oil refinery industry is the upgrading of low-quality distillate fractions, such as light cycle oil (LCO), in order to meet current quality standards for diesel fuels. An auspicious technological alternative entails the complete saturation of the aromatic structures followed by the selective cleavage of endocyclic carbon-carbon bonds in the formed naphthenic rings (selective ring opening—SRO). This work reports the influence of Brønsted acid sites of platinum-ultra stable Y zeolite (Pt-USY) catalysts in the SRO of decalin as a model naphthenic feed. A maximum combined yield to selective ring opening products (ROP: C10-alkylcycloalkanes + OCD: C10-alkanes) as high as 28.6 wt% was achieved for 1.6Pt-NaUSY-im catalyst. The molar carbon distribution curve of the hydrocracked (C9-) products varied from M-shaped for 1.4Pt-USY-im catalyst, indicating mainly C–C bond cleavage of the ring opening products with one remaining naphthenic ring via carbocations and the paring reaction, to not M-shaped for the 1.6Pt-NaUSY-im catalyst, where carbon-carbon bond cleavage occurs preferentially through a hydrogenolysis mechanism on metal sites. High (hydro)thermal stability and secondary mesoporosity of the 1.6Pt-NaUSY-im catalysts make this system highly prospective for upgrading low-quality real distillate feeds.

Decalin Ring Opening on Heterogeneous Me/Saponite Nanocatalysts (Me = Rh, Ru, and Ir)

“…Most often, SRO catalysts are classified based on the proposed mechanism of the hydrodecyclization (hydrogenolysis) reaction. This classification system was formulated by Weitkamp and is now often used when discussing the results obtained in the study of the SRO process. ,− According to this classification, SRO catalysts are divided into mono- and bifunctional systems. Monofunctional catalysts include catalysts based on acidic zeolites, as well as catalysts containing noble metals on oxide supports. , In bifunctional catalysts, metals are supported on wide-pore zeolites (H-FAU and H-β) with strong Brønsted acidity.…”

Synthesis and Application of Zeolite Catalysts

“…Various noble metal ions such as Ru, Rh, and Pd can also be incorporated to the MOR zeolite, which were used for the catalytic transfer hydrogenolysis of glycerol to produce 2-isopropoxy-propan-1-ol as a single product [10]. Similarly, Pt-incorporated USY zeolite exhibited bifunctional catalytic activity in the selective hydrocracking of decalin for upgrading low-quality real distillate feeds [11]. The acidity in Pt-loaded MRE zeolite was controlled by the addition of pseudoboehmite, by which the Pt-loaded hybrid catalyst showed very high catalytic activity in ring enlargement reaction of methylcyclopentane to produce benzene with high selectivity [12].…”