High-performance ring-opening catalysts based on iridium-containing zeolite Beta in the hydroconversion of decalin

Santi, Dominic; Holl, Tobias; Calemma, Vincenzo; Weitkamp, Jens

doi:10.1016/j.apcata.2013.01.020

Cited by 45 publications

(51 citation statements)

References 30 publications

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“…Different from the PH 3 LDEs discussed below, the other bri CO LDEs, from $39 to $46 kcal/mol, are close to or even slightly greater than those of api CO, ranging from $37 to $47 kcal/mol. This result suggests that carbonyls can bind to two Ir atoms more efficiently than PH 3 .…”

Section: Ir 4 (Ph 3 ) Y (Co) Z Structures Relative Energies and Dismentioning

confidence: 84%

“…Iridium clusters catalyze a wide range of reactions, including oxidation, hydrogenation, C-H bond activation, cycloaddition, cycloisomerization [1,2], and ring-opening [3]. Iridium complexes play important roles in oxidation (e.g., of alcohols [4][5][6], phenols [7][8][9], and amines [10,11]), hydrogenation [12,13], C-H activation [14][15][16], cycloaddition (e.g., [2 + 2 + 2] [17][18][19], [2 + 2 + 1] [20,21], and [4 + 2] [22,23]), cycloisomerization [1,2], and ring-opening reactions [24].…”

Section: Introductionmentioning

confidence: 99%

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Structures, relative energies, and ligand dissociation energies of iridium carbonyl phosphine clusters

Zhang

Katz

Gates

et al. 2015

Computational and Theoretical Chemistry

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a b s t r a c tThere is significant interest in the catalytic properties of substituted iridium carbonyl clusters but little thermodynamic information available characterizing them. The low-energy isomers of Ir x (PH 3 ) y (CO) z (x = 1, 2, 4) were investigated with density functional theory and correlated molecular orbital theory at the coupled cluster CCSD(T) level. The relative energies and ligand dissociation energies were calculated. Differences in relative energies are consequences of both electronic and steric effects of the phosphines and carbonyls. The calculations predict three fundamental structural types for Ir 2 (PH 3 ) y (CO) z : C 2v , C 2 , and D 3d . Ten exchange-correlation functionals were used for the ligand dissociation energy calculations in addition to CCSD(T) for the smaller clusters. The xB97X-D functional gave the most consistent ligand dissociation energies as compared with the CCSD(T) benchmark calculations, and, so it was used to predict the dissociation energies for larger clusters when CCSD(T) calculations were infeasible. The dissociation energies characteristic of Ir 4 (PH 3 ) y (CO) z were in the range of $30 to $60 kcal/mol. Dissociation of a bridging ligand often involved a hydrogen atom transfer from a phosphine to a coordinatively unsaturated iridium atom and a phosphine converting from a bridging site to an equatorial site. The products of such reactions are predicted to have lower relative energies than other isomers.Phosphines act as r-electron donors, and there is a trend of an increase in carbonyl ligand dissociation energies as more phosphines are substituted in the small clusters.

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Section: Ir 4 (Ph 3 ) Y (Co) Z Structures Relative Energies and Dismentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Structures, relative energies, and ligand dissociation energies of iridium carbonyl phosphine clusters

Zhang

Katz

Gates

et al. 2015

Computational and Theoretical Chemistry

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“…fuel. 2 While the selective ring opening (SRO) of naphthenic molecules is a promising pathway for heavy residue upgrading and it has been studied by many researchers, SRO still presents challenges due to a complex chemistry, product selectivities, operation conditions, composition of the final products, and the catalytic system. 3 In the catalytic system, a bi-functional catalytic system (metallic and acidic functions) is required in the SRO of naphthenic molecules.…”

Section: Introductionmentioning

confidence: 99%

Ring Opening of Naphthenic Molecules Over Metal Containing Mesoporous Y Zeolite Catalyst

Lee¹,

Kim²,

Kim³

et al. 2015

j nanosci nanotechnol

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Mesoporous Y zeolite (Meso-Y) with a uniform mesopore was synthesized via pseudomorphic syn- thesis. The Meso-Y supported Ni-W catalyst (NiW/Meso-Y) was introduced as a catalyst for the selective ring opening of naphthenic rings. The catalytic test for the ring opening of naphthalene as a model compound of multi-ring aromatics was performed using a batch-type reaction system with both sulfided 20 wt% NiW/Meso-Y and NiW/Y catalysts under different reaction conditions. The catalytic results reveal that the Meso-Y supported NiW catalyst experiences a naphthalene conversion similar to the NiW/Y catalyst, but the NiW/Meso-Y catalyst has higher product yields for BTEX (benzene, toluene, ethyl benzene, and xylene) and the middle distillate than those of the NiW/Y catalyst at a low reaction temperature. These results suggest that the mesoporosity of the NiW/Meso-Y catalyst is more advantageous for the ring opening reaction of multi-ring aromatics due to the easier access for the bulky molecules compared to the NiW/Y catalyst.

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“…As principais fontes de alumínio são aluminato de sódio, alumínio metálico, além da pseudoboemita (KONG et al, 2009), do sulfato de alumínio (SANTI et al, 2013), do nitrato de alumínio ( VAN DER MYNSBRUGGE et al, 2012) e do caolin (DUAN et al, 2011). Como fontes de sílica encontram-se, principalmente, a sílica fumê, a sílica coloidal e o tetraetilortosilicato e, como alternativas, a sílica gel (WANG et al, 2004) e também a cinza da casca de arroz (PRASETYOKO et al, 2006).…”

Section: Introductionunclassified

Cinzas De Casca De Arroz Como Fonte Alternativa De Silício Para a Síntese De Zeólita Beta

Enzweiler

Barbosa-Coutinho

Schwaab

2014

REGET

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ResumoCinzas de casca de arroz são resíduos agroindustriais gerados em larga escala que podem acarretar problemas ambientais e riscos à saúde da população. Como solução para este problema, as cinzas podem ser utilizadas como fonte alternativa de sílica altamente reativa, com vasto campo de aplicação, como, por exemplo, na síntese de catalisadores de alto teor de silício, como as zeólitas. Neste trabalho, zeólita beta foi sintetizada usando sílica amorfa, extraída de cinzas de casca de arroz, e pseudoboemita. Utilizando esta fonte alternativa de silício foi possível a formação da estrutura zeolítica com excelentes propriedades catalíticas. A aplicação da zeólita beta na desidratação do isopropanol possibilitou a produção de propeno com alta seletividade a baixas temperaturas, mostrando que a utilização de sílica proveniente de cinzas de cascas de arroz tem grande potencial tecnológico e ambiental.Palavras-chave: Zeólita beta; catalisador; cinzas de casca de arroz; isopropanol; propeno. AbstractRice husk ash is an agroindustrial residue generated in large scale that can cause environmental problems and risks to people health. As a solution to this problem, this ash could be used as an alternative source of high reactive silica, with a wide field of applications, such as, for example, in the synthesis of catalysts with high silicon content. In this work, beta zeolite was synthesized using amorphous silica, extracted from rice husk ash, and pseudo-boehmite. Using this alternative source of silicon, it was possible to form the zeolitic structure with excellent catalytic properties. The application of the beta zeolite in the dehydration of isopropanol enables the production of propylene with high selectivity at low temperatures, showing that the use of silica from rice husk ash has a great technological and environmental potential.

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High-performance ring-opening catalysts based on iridium-containing zeolite Beta in the hydroconversion of decalin

Cited by 45 publications

References 30 publications

Structures, relative energies, and ligand dissociation energies of iridium carbonyl phosphine clusters

Structures, relative energies, and ligand dissociation energies of iridium carbonyl phosphine clusters

Ring Opening of Naphthenic Molecules Over Metal Containing Mesoporous Y Zeolite Catalyst

Cinzas De Casca De Arroz Como Fonte Alternativa De Silício Para a Síntese De Zeólita Beta

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