Solvent‐Free Synthesis and <i>n</i>‐Hexadecane Hydroisomerization Performance of SAPO‐11 Catalyst

Du, Yonghua; Feng, Bing; Jiang, Ying; Yuan, Long; Huang, Keke; Li, Jiusheng

doi:10.1002/ejic.201800134

Cited by 29 publications

(24 citation statements)

References 56 publications

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“…An ideal hydroisomerization catalyst should achieve high isomerization selectivity for long-chain hydrocarbons, resulting in a high liquid yield, avoiding at the same time any parallel reactions resulting in the formation of cracked products. Hydroisomerization occurs consecutively (Figure 2) [13][14][15] when n-alkane is first dehydrogenated on a metal site forming an alkene, and thereafter a carbenium ion, which in turn is isomerized onto an acidic site to an isoolefin through an isocarbocation, finally forming bi-or multibranched alkanes (Figure 3) [13,16]. Alkylcarbenium ions can also further undergo β-scission reaction [17], forming cracking products.…”

Section: Reaction Mechanism In Hydroisomerization Of Long-chain Paraffinsmentioning

confidence: 99%

Catalytic Hydroisomerization of Long-Chain Hydrocarbons for the Production of Fuels

et al. 2018

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Hydroisomerization of long chain paraffins for the production of branched alkanes has recently been intensively studied due to a large availability of these compounds. The most interesting research topics have been the development of novel bifunctional catalysts to maximize the yield of isomers and to suppress the cracking reactions. Since both of these reactions are catalyzed by Brønsted acid sites, the optimum catalyst exhibits equal amounts of metal and acid sites, and it facilitates rapid mass transfer. Thus, several hierarchical and nano-shaped zeolites have been developed, in addition to composite catalysts containing both micro- and mesoporous phases. In addition to catalyst development, the effect of the reactant structure, optimal reaction conditions, catalyst stability and comparison of batch vs continuous operations have been made.

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Section: Reaction Mechanism In Hydroisomerization Of Long-chain Paraffinsmentioning

confidence: 99%

Catalytic Hydroisomerization of Long-Chain Hydrocarbons for the Production of Fuels

et al. 2018

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“…This method leads to significant reduction of waste and solvent use as well as the synthesis procedure is shortened significantly. It differs from the solvent-free methodthat requires pre-reaction of the raw materials and washing of intermediates with ethanol [28,29]. The features of metal andacid sites over the Ni/SAPO-11 catalyst were investigated systematically.…”

Section: Introductionmentioning

confidence: 99%

Metal and acid sites instantaneously prepared over Ni/SAPO-11 bifunctional catalyst

Lyu

Yang

et al. 2019

Journal of Catalysis

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The Ni/SAPO-11 bifunctional catalyst for hydroisomerization of n-hexane was prepared via a novel synthesis method. It involved grinding of nickel source with amorphous precursors used for SAPO-11 followed by crystallization at 473 K for 24 h, thus avoiding the use of extra solvents in the synthesis. The highly dispersed nickel species and acid sites in the Ni/SAPO-11 bifunctional catalyst were instantaneouslyformed. The Ni/SAPO-11 catalyst contains framework nickel, nickel monoxide (NiO) and nickel aluminate spinel. The nickel monoxide with a size of 2-4 nm provides (de)hydrogenation function after reduction, while the framework nickel supplies more acid sites leading to an enhancedisomerization activity.The Ni/SAPO-11 catalyst shows a great synergeticeffect between the metallic nickel and acid sites with a high metal-to-acid sites ratio (C Ni /C A ) and close proximity. A single metallic nickel site is able to balance ca. 5 acid sites (C Ni /C A ≈0.19) over the Ni/SAPO-11 catalyst in n-hexane hydroisomerization.The high dispersion of nickel over the catalyst provides relatively excessive metal sites (C Ni /C A >0.19), leaving the rate limiting reaction to occur on the acid sites. The Ni/SAPO-11 catalyst exhibits comparable n-hexane conversion (71.2%) and iso-hexane yield (66.7%) to the classical Pt/SAPO-11 catalyst.With enhancing acidity, the Ni/SAPO-11 catalyst exhibits one of the highest iso-hexane yields reported in the n-hexane hydroisomerization, which render the new material as a promising candidate for the hydroisomerization catalysts.

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“…The higher isomerization activity of Pt/SAPO‐11‐GO is different from the previous modified Pt/SAPO‐11 samples, normally accompanied with the lower isomerization activity. For instance, according to our previous research, hierarchical Pt/SAPO‐11 catalyst synthesized with the addition of cetyltrimethylammonium bromide (CTAB) showed lower isomerization activity for the decrease of acidic sites than conventional microporous Pt/SAPO‐11 synthesized without CTAB via the non‐solvent method . Furthermore, Pt/SAPO‐11‐GO synthesized with more GO also exhibited higher isomerization activity, due to their enhanced material crystallinities, shown in Figure S5.…”

Section: Resultsmentioning

confidence: 91%

“…It can be indicated in Table that the amount of total acidic sites increased from 33.83 to 75.88 μmol g −1 largely due to the increase of the Lewis acid sites (from 26.80 to 54.91 μmol g −1 ) for SAPO‐11 and SAPO‐11‐GO samples. Achieved from the XPS analysis in Table , there were more Al content and more Al‐OH on the surface of the SAPO‐11‐GO sample, compared to the SAPO‐11 sample, resulting in the formation of more Lewis acid sites …”

Section: Resultsmentioning

confidence: 99%

Graphene Oxide Induced High Crystallinity of SAPO‐11 Molecular Sieves for Improved Alkane Isomerization Performance

Yao

Zhao

et al. 2019

ChemNanoMat

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In the presence of graphene oxide (GO), highly crystallized SAPO‐11 molecular sieves were prepared by a non‐solvent method. The functional groups of GO bind with raw materials, with the formation of hydrogen bonds and acid amides, verified by the XPS analysis. The inorganic precursor and structure‐directing agent molecules will be fixed on the surface of GO, increasing the reaction rate and crystallization for SAPO‐11 preparation, confirmed by the XRD and BET results. Meanwhile, the IR analysis of the adsorption of pyridine indicates there are more acidic sites for the highly crystallized SAPO‐11 sample. The resultant well‐crystallized SAPO‐11 molecular sieves exhibited greater isomer yield and better catalytic activity compared to traditional SAPO‐11 prepared without GO.

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Solvent‐Free Synthesis and n‐Hexadecane Hydroisomerization Performance of SAPO‐11 Catalyst

Cited by 29 publications

References 56 publications

Catalytic Hydroisomerization of Long-Chain Hydrocarbons for the Production of Fuels

Catalytic Hydroisomerization of Long-Chain Hydrocarbons for the Production of Fuels

Metal and acid sites instantaneously prepared over Ni/SAPO-11 bifunctional catalyst

Graphene Oxide Induced High Crystallinity of SAPO‐11 Molecular Sieves for Improved Alkane Isomerization Performance

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