- Hydrodesulfurization of 4,6-DMDBT in the high boiling fraction of gas oil
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A high boiling fraction of straight run gas oil, which contained 4,6-DMDBT by addition but free from dimethylbiphenyl and dimethylcyclohexylbenzene of its HDS products, was desulfurized over commercial catalysts to find principal products of 4,6-DMDBT. Thus, HDS of 4,6-DMDBT in the high boiling fraction of real feed was proved to proceed principally through hydrogenative route. During the HDS of the fraction, 4,6-DMDBT was found to be produced from trimethyldibenzothiophenes. This activity depended very much on the acidity of the catalyst.
- Choi, Ki-Hyouk,Korai, Yozo,Mochida, Isao
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- Palladium effect over Mo and NiMo/alumina-titania sulfided catalysts on the hydrodesulfurization of 4,6-dimethyldibenzothiophene
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The influence of Pd as additive for Ni and Mo catalysts supported on alumina-titania (Mo/AT) sulfided catalysts was investigated in the hydrodesulfurization of 4,6-dimethyldibenzothiophene. Pd incorporation was carried out in the oxidic phases by using sequential impregnation. The alumina-titania support was formed by anatase-TiO2 crystallites randomly dispersed on γ-Al2O3. Characterization by X-ray diffraction and Raman spectroscopy revealed that MoOx species for PdMo supported on alumina-titania displayed larger particles than those in PdNiMo catalysts. HRTEM images showed an increase in order and stacking for MoS 2 slabs after Pd addition to NiMo samples, as compared with Mo/AT. Pd incorporation over the NiMo/AT sample increased the reaction rate by 30% while no significant increase was recorded for the PdMo sample. This value corresponds to the most active catalyst and it points out to a promoting effect by Pd. This prominent hydrodesulfurization capacity for the PdNiMo/AT suggests a close interaction of Pd with NiMo. Furthermore, since Pd promoted the HDS activity for a NiMo system, the alumina-titania support played an important role.
- Aguirre-Gutierrez,De La Fuente, J.A. Montoya,De Los Reyes,Del Angel,Vargas
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- Noble metal silicides catalysts with high stability for hydrodesulfurization of dibenzothiophenes
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Development of highly efficient and long stable hydrodesulfurization (HDS) catalysts still is a great challenge for the refining industry. In this work, a series of intermetallic noble metal silicides supported by carbon nanotubes catalysts (Pt2Si/CNTs, RhxSi/CNTs, and RuSi/CNTs) have been developed by chemical vapor deposition successfully, using dichlorodimethylsilane as Si source. These materials were used as efficient catalysts for the deep HDS of dibenzothiophenes (4,6-DMDBT and DBT) and performed high selectivity to the direct desulfurization pathway. The sequence of HDS activity over noble metal silicides catalysts is in keeping with the sequence of HDS activity of the corresponding metal catalysts, which is Pt2Si/CNTs > RhxSi/CNTs >> RuSi/CNTs. In addition, the Pt2Si/CNTs performed an excellent stability in 100 h stability testing for HDS of 4,6-DMDBT. Therefore, this sulfur-tolerant noble metal silicides could be as promising catalysts for the ultra-deep HDS of fossil-fuel.
- Yang, Kaixuan,Chen, Xiao,Bai, Zongxuan,Liang, Changhai
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- Isomerization of substituted biphenyls by superacid. A remarkable confluence of experiment and theory
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Acid-catalyzed isomerization of dimethylbiphenyls is determined by the relative stability of intermediate carbocations, rather than the neutral products, and may be predicted by a simple semiempirical method (AM1). A general kinetic model for such isomeri
- Sherman, S. Christopher,Iretskii, Alexei V.,White, Mark G.,Gumienny, Charles,Tolbert, Laren M.,Schiraldi, David A.
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- Mechanism of reaction of trans-diarylbis(diethylphenylphosphine)palladium(II) complexes with aryl iodides to give biaryls
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The mechanism of reaction of trans-PdAr2L2 (Ar = m-tolyl or phenyl, L = PEt2Ph) with aryl iodides affording biaryls has been studied.The rate of reaction is independent of the concentration of aryl iodide but is significantly accelerated by the presence of trans-PdAr(I)L2.Cross-over experiments on the reaction of diarylpalladium complexes with monoarylpalladium iodides reveals the occurrence of two types of intermolecular processes between the diaryl and monoaryl complexes.The first process results in a scrambling of aryl groups between the diaryl and monoaryl complexes without formation of biaryls, while the second yields the reductive elimination products, biaryls.
- Ozawa, Fumiyuki,Hidaka, Takahiro,Yamamoto, Takakazu,Yamamoto, Akio
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- Hydrodesulfurization of 4,6-dimethyldibenzothiophene over promoted (Ni,P) alumina-supported molybdenum carbide catalysts: Activity and characterization of active sites
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The effect of phosphorus and nickel on alumina-supported molybdenum oxycarbides has been studied. Catalysts were characterized by elemental analysis, X-ray diffraction, CO chemisorption, transmission electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy. Propene and tetralin hydrogenation was used to probe the activity of the doped materials. Hydrodesulfurization of 4,6-dimethyldibenzothiophene (613 K and 4 MPa total pressure) was investigated as a probe for the deep HDS of diesel fuel. For contact times ranging from 0 to 0.4 s (conversion 4+ abundance, increase in the number of Lewis acid sites, and consequent enhancement of the DDS rate. Nickel induces the highest HDS activity; a nickel-molybdenum interaction observed by FTIR spectroscopy of adsorbed CO could be responsible for this behavior.
- Manoli,Da Costa,Brun,Vrinat,Mauge,Potvin
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- Activity of Mo(W)S2/SBA-15 Catalysts Synthesized from SiMoW Heteropoly Acids in 4,6-Dimethyldibenzothiophene Hydrodesulfurization
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Abstract: Mo(W)/SBA-15 catalysts are prepared using heteropoly acids H4SiMo12O40, H4SiW12O40, and H4SiMo3W9O40. The catalysts in the sulfide form are studied by low-temperature nitrogen adsorption, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Catalytic properties are tested in the hydrodesulfurization of 4,6-dimethyldibenzothiophene. It is shown that the gas-phase sulfiding of Mo(W)/SBA-15 catalysts leads to increase in the average length of particles and the number of Mo(W)S2 layers in active phase particles compared with liquid-phase sulfiding with the use of dimethyl sulfide. The replacement of a quarter of tungsten atoms with molybdenum ones makes it possible to considerably improve the catalytic activity of the mixed catalyst Mo + W/SBA-15 compared with the monometallic counterparts. This effect can be enhanced due to the use of mixed heteropoly acid H4SiMo3W9O40 as a precursor of the active phase of the MoW/SBA-15 catalyst, which is apparently associated with the formation of MoWS2 active sites.
- Koklyukhin,Nikul’shina,Sheldaisov-Meshcheryakov,Mozhaev,Lancelot,Blanchard,Lamonier,Nikul’shin
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- Investigation of 4,6-dimethyldibenzothiophene hydrodesulfurization over a highly active bulk MoS2 catalyst
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The hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene was investigated in a batch-stirred microautoclave reactor over a laboratory-synthesized MoS2 catalyst. The reaction was found to proceed through two main parallel pathways: direct desulfurization (DDS) and hydrogenation (HYD). The effect of a wide range of H2S concentrations on the HDS activity and selectivity was studied. Contrary to the well-known inhibition of HDS caused by H2S, the global catalytic activity of HDS was enhanced more than two times with inclusion of H2S in the reaction zone. The increase in the activity is attributed to a significant enhancement in the hydrogenation reaction route, while the direct desulfurization products were only slightly affected. It is suggested that H2S modifies the active sites so that they can be exploited more efficiently in the hydrogenation reaction.
- Farag, Hamdy,Sakanishi, Kinya
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- Visible Light Induced Aerobic Coupling of Arylboronic Acids Promoted by Hydrazone
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A visible-light-induced oxidative coupling of arylboronic acids has been developed for the synthesis of biaryls. The reaction that employs polydentate hydrazones as the bifunctional catalyst works smoothly under room temperature. It is compatible with a w
- Xia, Hongyu,Wang, Ganghu,Zhao, Dongbo,Zhu, Chunyin
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supporting information
p. 922 - 929
(2022/02/10)
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- Ligand and Base Free Synthesis of Biaryls from Aryl Halides in Aqueous Media with Recyclable Ti0.97Pd0.03O1.97 Catalyst
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Abstract: Facile protocol for the synthesis of biaryls from aryl halides in presence of magnesium metal without prior formation of organometallic intermediate has been exploited. Irrespective of aqueous medium, Ti0.97Pd0.03O1.97 catalyst supports C–C bond formation reaction in presence of metals rather than dehalogenation without any additives. Homocoupling of 16 different aryl halides furnished corresponding biphenyls in good yield with better functional group tolerance. The recovery of the catalyst was carried out by employing catalyst coated cordierite monolith up to 7th cycle with high yields. A new approach for the cross-coupling reaction is also attempted. Graphic Abstract: [Figure not available: see fulltext.]
- Prasanna,Bhat, Shrikanth K.,Usha,Hegde
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p. 3313 - 3322
(2021/03/04)
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- Zirconium-redox-shuttled cross-electrophile coupling of aromatic and heteroaromatic halides
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Transition metal-catalyzed cross-electrophile coupling (XEC) is a powerful tool for forging C(sp2)–C(sp2) bonds in biaryl molecules from abundant aromatic halides. While the synthesis of unsymmetrical biaryl compounds through multimetallic XEC is of high synthetic value, the selective XEC of two heteroaromatic halides remains elusive and challenging. Herein, we report a homogeneous XEC method, which relies on a zirconaaziridine complex as a shuttle for dual palladium-catalyzed processes. The zirconaaziridine-mediated palladium (ZAPd)-catalyzed reaction shows excellent compatibility with various functional groups and diverse heteroaromatic scaffolds. In accord with density functional theory (DFT) calculations, a redox transmetallation between the oxidative addition product and the zirconaaziridine is proposed as the crucial elementary step. Thus, cross-coupling selectivity using a single transition metal catalyst is controlled by the relative rate of oxidative addition of Pd(0) into the aromatic halide. Overall, the concept of a combined reducing and transmetallating agent offers opportunities for the development of transition metal reductive coupling catalysis.
- Fu, Yue,Liu, Fang-Jie,Liu, Peng,Tang, Jian-Tao,Toste, F. Dean,Wu, Ting-Feng,Ye, Baihua,Zhang, Yue-Jiao
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supporting information
p. 1963 - 1974
(2021/07/07)
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- Reductive Coupling of Aryl Halides via C—H Activation of Indene
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This paper describes the first case of a reductive coupling reaction with indene, a non-heteroatom olefin used as a reducing agent. The scope of the substrate is wide. The homo-coupling, cross-coupling, and synthesis of 12 and 14-membered rings were realized. The control experiment, indene-product curve and density functional theory calculations showed that the η3-palladium indene intermediate was formed by C—H activation in the presence of cesium carbonate. We speculate that the final product was obtained through a Pd (IV) intermediate or aryl ligand exchange. In addition, we excluded the formation of palladium anion (Pd(0)?) intermediates.
- Zhang, Bo-Sheng,Yang, Ying-Hui,Wang, Fan,Gou, Xue-Ya,Wang, Xi-Cun,Liang, Yong-Min,Li, Yuke,Quan, Zheng-Jun
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p. 1573 - 1579
(2021/05/28)
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- Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate
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Pairing lithium and manganese(II) to form lithium manganate [Li2Mn(CH2SiMe3)4] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C?C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C?C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH2SiMe3 during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.
- Uzelac, Marina,Mastropierro, Pasquale,de Tullio, Marco,Borilovic, Ivana,Tarrés, Màrius,Kennedy, Alan R.,Aromí, Guillem,Hevia, Eva
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supporting information
p. 3247 - 3253
(2020/12/11)
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- Synthesis of biaryl compounds via Suzuki homocoupling reactions catalyzed by metal organic frameworks encapsulated with palladium nanoparticles
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Heterogeneous homocoupling reactions of phenylboronic acids were greatly accelerated via Suzuki homocoupling reactions. In this work, a tandem route was designed which firstly one part of phenylboronic acids reacted with iodine to form iodobenzenes, then another part of phenylboronic acids coupled with iodobenzenes to produce biaryl compounds. The tandem reaction were catalyzed by a bifunctional heterogeneous catalyst of metal organic frameworks encapsulated with palladium nanoparticles (Pd?MOFs). This strategy for forming symmetric C-C bond between benzene rings has obvious advantages such as high efficiency, easy separation, good recyclability and no addition of toxic halogenated benzene.
- Bao, Yan-Sai,Cui, Xin-Yu,Han, Zheng-Bo,Li, Xin,Tang, Hong,Yang, Ming,Zhang, Yu-Yang,Zhao, Kun,Zhou, Mei-Li
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- Pd-catalyzed oxidative homocoupling of arylboronic acids in WEPA: A sustainable access to symmetrical biaryls under added base and ligand-free ambient conditions
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Symmetrical and unsymmetrical biaryls comprises a diverse class of biologically eloquent organic compounds. We herein report, a quick and eco-friendly protocol for the synthesis of biaryls by an oxidative (aerobic) homocoupling of arylboronic acids (ABAs) using Pd(OAc)2 in water extract of pomogranate ash (WEPA) as an efficient agro-waste(bio)-derived aqueous (basic) media. The reactions were executed at ambient aerobic conditions in the absence of external base and ligand to result symmetrical biaryls in excellent yields. The use of renewable media with an effective exploitation of waste, short reaction times, excellent yields of products, easy separation of the products, unnecessating the external base, oxidant, ligand or volatile organic solvents and ambient reaction conditions are the vital insights of the present protocol.
- Appa, Rama Moorthy,Lakshmidevi, Jangam,Naidu, Bandameeda Ramesh,Venkateswarlu, Katta
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- Sustainable Synthesis of Biaryls Using Silica Supported Ferrocene Appended N-Heterocyclic Carbene-Palladium Complex
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Abstract: A novel silica supported ferrocene appended N-heterocyclic carbene-palladium complex (SilFemBenzNHC@Pd) has been prepared and characterized by using fourier transform infrared (FT-IR), fourier transform Raman (FT-Raman), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and energy dispersive X-ray analysis (EDX). This novel complex served as a robust heterogeneous catalyst for the synthesis of biaryls via homocoupling of aryl boronic acids under base-free conditions in water. Recyclability experiments were executed successfully for six successive runs. Graphic Abstract: [Figure not available: see fulltext.]
- Khanapure, Sharanabasappa,Pore, Dattaprasad,Jagadale, Megha,Patil, Vaishali,Rashinkar, Gajanan
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p. 2237 - 2249
(2021/01/11)
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- Porphyrin n-pincer pd(Ii)-complexes in water: A base-free and nature-inspired protocol for the oxidative self-coupling of potassium aryltrifluoroborates in open-air
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Metalloporphyrins (and porphyrins) are well known as pigments of life in nature, since representatives of this group include chlorophylls (Mg-porphyrins) and heme (Fe-porphyrins). Hence, the construction of chemistry based on these substances can be based on the imitation of biological systems. Inspired by nature, in this article we present the preparation of five different porphyrin, meso-tetraphenylporphyrin (TPP), meso-tetra(p-anisyl)porphyrin (TpAP), tetra-sodium meso-tetra(p-sulfonatophenyl)porphyrin (TSTpSPP), meso-tetra(m-hydroxyphenyl)porphyrin (TmHPP), and meso-tetra(m-carboxyphenyl)porphyrin (TmCPP) as well as their N-pincer Pd(II)-complexes such as Pd(II)-meso-tetraphenylporphyrin (PdTPP), Pd(II)-meso-tetra(p-anisyl)porphyrin (PdTpAP), Pd(II)-tetrasodium meso-tetra(p-sulfonatophenyl)porphyrin (PdTSTpSPP), Pd(II)-meso-tetra(m-hydroxyphenyl)porphyrin (PdTmHPP), and Pd(II)-meso-tetra(m-carboxyphenyl)porphyrin (PdTmCPP). These porphyrin N-pincer Pd(II)-complexes were studied and found to be effective in the base-free self-coupling reactions of potassium aryltrifluoroborates (PATFBs) in water at ambient conditions. The catalysts and the products (symmetrical biaryls) were characterized using their spectral data. The high yields of the biaryls, the bio-mimicking conditions, good substrate feasibility, evading the use of base, easy preparation and handling of catalysts, and the application of aqueous media, all make this protocol very attractive from a sustainability and cost-effective standpoint.
- Hanafiah, Marlia M.,Lakkaboyana, Sivarama Krishna,Lakshmidevi, Jangam,Marella, Ravi Kumar,Naidu, Bandameeda Ramesh,Prasad, Sana Siva,Venkateswarlu, Katta
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- Nickel- and Palladium-Catalyzed Cross-Coupling Reactions of Organostibines with Organoboronic Acids
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A strategy for the formation of antimony-carbon bond was developed by nickel-catalyzed cross-coupling of halostibines. This method has been applied to the synthesis of various triaryl- and diarylalkylstibines from the corresponding cyclic and acyclic halostibines. This protocol showed a wide substrate scope (72 examples) and was compatible to a wide range of functional groups such as aldehyde, ketone, alkene, alkyne, haloarenes (F, Cl, Br, I), and heteroarenes. A successful synthesis of arylated stibine 3 a in a scale of 34.77 g demonstrates high synthetic potential of this transformation. The formed stibines (R3Sb) were then used for the palladium-catalyzed carbon–carbon bond forming reaction with aryl boronic acids [R?B(OH)2], giving biaryls with high selectivity, even the structures of two organomoieties (R and R′) are very similar. Plausible catalytic pathways were proposed based on control experiments.
- Zhang, Dejiang,Le, Liyuan,Qiu, Renhua,Wong, Wai-Yeung,Kambe, Nobuaki
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supporting information
p. 3104 - 3114
(2020/12/11)
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- Controllable Synthesis of Defect-Rich CoMoS Catalysts with Different Morphologies for the Ultradeep Hydrodesulfurization of 4,6-Dimethydibenzothiophene
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CoMoS catalysts with controllable morphology are prepared by a single-source precursor hydrothermal method using sodium diethyldithiocarbamate trihydrate (DDTC) as the ligand and the sulfur source. The effects of the single-source precursor, the pH of the hydrothermal solution, and the surfactant with respect to the morphology, nanostructure, and hydrodesulfurization (HDS) activity of the CoMoS catalyst are investigated. It is revealed that the coordination between the metal atom and DDTC can effectively control the in-plane and out-of-plane crystal growth of MoS2 and promote the formation of the CoMoS active phase. The lower pH value of the hydrothermal solution facilitates the synthesis of CoMoS catalysts with improved purity, lower crystallinity, and smaller nanocrystallites, and the different surfactants would significantly change the morphologies. For HDS activity, the conversion efficiency of 4,6-DMDBT is increased from 71 to 99% by the CoMoS catalysts that have fewer stacking layers of MoS2 slabs. While the high HDS activity is maintained, a notable improvement in selectivity for the direct desulfurization (DDS) pathway is observed for the CoMoS-CTAB catalyst, where the average slab length of MoS2 is the longest.
- Han, Yuanyuan,Liu, Yongjun,Niu, Xiantao,Zhou, Weixia
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p. 14254 - 14264
(2021/12/13)
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- Palladium/Sensory Component-Catalyzed Homocoupling Reactions of Aryl Halides
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A novel and efficient catalyst system was developed for homocoupling reactions of aryl halides. The catalyst system consists of Pd(OAc) 2and the peppery sensory component of tobacco leaves. This is the first time that a sensory component has been used in an organic reaction. Experiments using the catalyst system showed that the reactions proceeded smoothly under air in the absence of both an additional ligand and a reductant. Furthermore, the catalyst system can be applied to the coupling reactions of hetaryl iodides. Many functional groups (including a hydroxy group) are tolerated.
- Bai, Haixin,Bao, Fengyu,Chai, Guobi,Liu, Pengfei,Liu, Zhikai,Zhang, Haiyan,Zhang, Qidong
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supporting information
(2020/09/09)
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- Ultradeep hydrodesulfurization of fuel over superior NiMoS phases constructed by a novel Ni(MoS4)2(C13H30N)2precursor
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This article presents novel decyltrimethylammonium bromide-dispersed Ni-Mo sulfide (DTMA-NiMo) as a precursor for preparing an efficient NiMoS/γ-Al2O3hydrodesulfurization (HDS) catalyst. The as-synthesized DTMA-NiMo is a sulfide containing both long-chain quaternary ammonium and Ni-Mo-S elements. The proposed method not only significantly improves the dispersion of Mo species but also greatly promotes the incorporation of Ni into MoS2slabs, leading to an increase in the number of NiMoS phases. As a result, the DTMA-NiMo-based NiMoS/γ-Al2O3catalyst exhibits much higher activity for the HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and fluid catalytic cracking (FCC) diesel than NiMoS/γ-Al2O3catalysts prepared by the co-impregnation and tetrapropylammonium bromide (TPAB)-assisted methods. This novel strategy sheds a light on the facile and low-cost preparation of superior NiMoS phases without sulfidation treatment.
- Fan, Yu,He, Shuisen,Wen, Chenglong,Xu, Jundong
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p. 6065 - 6075
(2020/09/23)
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- MICRO-ELECTROLYSIS REACTOR FOR ULTRA FAST, OXIDANT FREE, C-C COUPLING REACTION AND SYNTHESIS OF DACLATASVIR ANALOGS THEREOF
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The present invention relates to a continuous micro-electro-flow reactor system for ultra-fast, oxidant free, C—C coupling reaction for making symmetrical biaryls and analogs thereof. This invention further relates to the said process for preparation of antiviral drug, daclatasvir of general formula I.
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Paragraph 0105-0110; 0117-0121
(2020/12/01)
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- Synthesis of highly ordered TiO2-Al2O3 and catalytic performance of its supported NiMo for HDS of 4, 6-dimethyldibenzothiophene
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The highly ordered mesoporous TiO2-Al2O3 composite oxides were prepared via a facile evaporation-induced self-assembly (EISA) method. All of those synthesized materials were characterized by means of XRD, XRF, N2 adsorption, FTIR, Py-FTIR and TEM. The results show that the hexagonally ordered mesoporous TiO2-Al2O3 oxides with high specific surface area, high thermal stability and narrow pore size distributions were successfully synthesized by EISA. The corresponding NiMo catalysts supported on TiO2-Al2O3 oxides were further characterized by H2-TPR, HRTEM and XPS. Their hydrodesulfurization catalytic performances were tested in a fixed-bed reactor, using 4,6-dimethyldibenzothiophene as the probe. The analyzing results exhibit that the incorporation of TiO2 could effective weaken the support-metal interactions, thus enhancing the reduction degree of active metals and forming more “Type II” Ni-Mo-S active phases that would be beneficial for the HDS of highly refractory organosulfur compound. The catalytic results reveal that the 4,6-DMDBT conversion over NiMo/TA-n catalysts gradually increased as the Ti/Al molar ratio increases, and reaches a maximum values at NiMo/TA-0.4. The NiMo/TA-0.4 exhibited the highest hydrodesulfurization catalytic performance of 4,6-DMDBT due to the synergistic effect of suitable textural properties, high thermal stability and moderate metal-support interactions.
- Liu, Xiaodong,Long, Yuchi,Mu, Fujun,Shan, Yacheng,Wei, Qiang,You, Qingxiang,Zhang, Pengfei,Zhou, Wuwen,Zhou, Yasong
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- Palladium Ion Catalysed Oxidative C–C Bond Formation Reactions in Arylboronic Acid: Application of Cordierite Monolith Coated Catalyst
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Abstract: Catalytic efficiency of palladium ion substituted in TiO2, Ti0.97Pd0.03O1.97 is successfully exploited for the oxidative homocoupling of arylboronic acid and oxidative Heck coupling reactions between arylboronic acid and olefins. The reaction protocol provides direct approach to synthesize biphenyls and cinnamates from moderate to good yield with good functional group tolerance. As a result, 11 symmetrical biaryls and 14 cinnamates were synthesized from readily available arylboronic acids. Ti0.97Pd0.03O1.97 powder catalyst is synthesized by solution combustion method and characterized by powder X-ray diffraction. The C–C bond formation reactions were carried out by catalyst cartridge method using Ti0.97Pd0.03O1.97 catalyst coated cordierite monolith. Coating of the catalyst on a cordierite monolith enhanced the applicability of the catalyst and made handling and recycling of the catalyst very easy. Catalyst was recovered and recycled for eight times in both homocoupling and oxidative Heck coupling reactions. The turnover number for both the reactions found to be 443 and 424, respectively. Graphic Abstract: [Figure not available: see fulltext.].
- Bhat, Shrikanth K.,Prasanna,Dasappa, Jagadeesh Prasad,Hegde
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p. 2911 - 2927
(2020/03/31)
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- Efficient Pd-catalyzed oxidative homocoupling of arylboronic acids in aqueous NaClO
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An efficient, mild and practical method was developed for the synthesis of biaryls via the Pd-catalyzed oxidative homocoupling of aromatic/heteroaromatic boronic acids in aqueous NaClO.
- Li, Min-Xin,Tang, Yan-Ling,Gao, Hui,Mao, Ze-Wei
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supporting information
(2020/03/04)
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- Green-Synthesized Nickel Nanoparticles on Reduced Graphene Oxide as an Active and Selective Catalyst for Suzuki and Glaser-Hay Coupling Reactions
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A mild and benign methodology to syntheses biaryls and 1,3-diynes has been demonstrated using the nickel nanoparticles supported on reduced graphene oxide (RGO-Ni) as a heterogeneous catalyst which is prepared using green reagents. A series of substituted biaryls and 1,3-diynes has been synthesised in good to excellent yields through C-C homocoupling reaction of arylboronic acids and terminal alkynes respectively using 1,4-dioxane as a benign solvent. The present ligand-free catalytic system proceeds smoothly under mild conditions, avoids noble and stoichiometric metal reagents and tolerates sensitive functional groups. Also has a wide substrate scope and feasible with other nitrogen and sulphur containing heteroaryl boronic acids. Hot filtration test unambiguously proves the true heterogeneity of the catalyst and which support for the further reusability of the catalyst for several times without any change in the activity. The easy preparation and simple magnetic separation, stability and reusability reveal that as-prepared RGO-Ni as a versatile catalyst for the synthesis of polyaromatic compounds both in academia and industries. Highlights: Green-synthesized RGO-Ni nanocomposite used as a heterogeneous catalyst for Suzuki type (C-C) and Glaser–Hay (C ≡ C) homocoupling coupling reactions. Ligand-free catalytic system and avoids noble and stoichiometric metal reagents Short reaction time with a minimum catalyst (nickel) loading RGO-Ni nanocomposite is highly stable, reusable, and magnetically retrievable.
- Murugan, Karthik,Nainamalai, Devarajan,Kanagaraj, Pavithara,Nagappan, Saravana Ganesan,Palaniswamy, Suresh
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- Synthesis of Enaminone-Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki-Miyaura Cross Coupling Reaction
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A series of Pd(II)-enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)-reagents has proved that the Pd(eao)2-1 possesses excellent catalytic activity for the Suzuki- Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)-reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2-2 has been found as a practical catalyst for the homo-coupling reactions of aryl boronic acids.
- Fu, Leiqing,Cao, Xiaoji,Wan, Jie-Ping,Liu, Yunyun
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p. 254 - 258
(2020/01/25)
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- Kinetically Controlled Reticular Assembly of a Chemically Stable Mesoporous Ni(II)-Pyrazolate Metal-Organic Framework
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The application scope of metal-organic frameworks (MOFs) is severely restricted by their weak chemical stability and limited pore size. A robust MOF with large mesopores is highly desired, yet poses a great synthetic challenge. Herein, two chemically stable Ni(II)-pyrazolate MOFs, BUT-32 and -33, were constructed from a conformation-matched elongated pyrazolate ligand through the isoreticular expansion. The two MOFs share the same sodalite-type net, but have different pore sizes due to the network interpenetration in BUT-32. Controlled syntheses of the two MOFs have been achieved through precisely tuning reaction conditions, where the microporous BUT-32 was demonstrated to be a thermodynamically stable product while the mesoporous BUT-33 is kinetically favored. To date, BUT-32 represents the first example of Ni4-pyrazolate MOF whose structure was unambiguously determined by single-crystal X-ray diffraction. Interestingly, the kinetic product BUT-33 integrates 2.6 nm large mesopores with accessible Ni(II) active sites and remarkable chemical stability even in 4 M NaOH aqueous solution and 1 M Grignard reagent. This MOF thus demonstrated an excellent catalytic performance in carbon-carbon coupling reactions, superior to other Ni(II)-MOFs including BUT-32. These findings highlight the importance of kinetic control in the reticular synthesis of mesoporous MOFs, as well as their superiority in heterogeneous catalysis.
- He, Tao,Huang, Zhehao,Yuan, Shuai,Lv, Xiu-Liang,Kong, Xiang-Jing,Zou, Xiaodong,Zhou, Hong-Cai,Li, Jian-Rong
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supporting information
p. 13491 - 13499
(2020/09/02)
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- Aerobic and Ligand-Free Manganese-Catalyzed Homocoupling of Arenes or Aryl Halides via in Situ Formation of Aryllithiums
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Ligand-free manganese-catalyzed homocoupling of arenes or aryl halides can be carried out under aerobic conditions via the in situ formation of the corresponding aryllithiums. A wide range of biaryls and derivatives has been obtained, and a mechanism involving monomeric manganese-oxo complexes has been proposed on the basis of DFT calculations.
- Liu, Yujia,Bergès, Julien,Zaid, Yassir,Chahdi, Fouad Ouazzani,Van Der Lee, Arie,Harakat, Dominique,Clot, Eric,Jaroschik, Florian,Taillefer, Marc
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p. 4413 - 4420
(2019/03/26)
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- Photocatalytic coupled redox cycle for two organic transformations over Pd/carbon nitride composites
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Heterogeneous photocatalysis offers a means for "green" organic transformations. Generally, photogenerated electrons and holes are not utilized simultaneously and effectively. Here we report a coupling approach to promote simultaneously two organic transformations of the Ullmann C-C coupling reaction and the value-added aromatic alcohol oxidation reaction in inert solvent and under anaerobic conditions using a carbon nitride based composite (Pd/CN-450) prepared by loading Pd nanoparticles (NPs) on CN-450 (N defect and O dopant co-modified g-C3N4 with high crystallinity). Upon photo-excitation of the photocatalyst, the activation of carbon-halogen bonds of the adsorbed aryl halides can be promoted by the photogenerated electrons on Pd NPs and the aromatic alcohols undergo dissociation and dehydrogenation, and finally can be oxidized by the captured photogenerated holes from CN-450 in the presence of a Br?nsted base. N defects, O doping, and improved crystallinity, controlled by changing the post-annealing temperature in molten salts, enhance the visible light absorption and improve charger carrier separation of the functionalized carbon nitride. The smaller size and high dispersity of Pd NPs give the higher surface area-to-volume ratio resulting in efficient adsorption and activation of reactant molecules on Pd NPs and allow for the effective interfacial interaction of CN-450 with Pd NPs for promoting electron transfer from CN-450 to Pd NPs. As a result, Pd/CN-450 displays a superior photocatalytic activity of the coupled reaction compared to Pd/g-C3N4 (Pd NP supported pristine g-C3N4). Moreover, the coupled reaction system has general applicability for various substrates and shows reusability.
- Jia, Qiaohui,Zhang, Sufen,Jia, Xiaoxia,Dong, Xiaoyang,Gao, Ziwei,Gu, Quan
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p. 5077 - 5089
(2019/10/05)
-
- Micro-electro-flow reactor (μ-EFR) system for ultra-fast arene synthesis and manufacture of daclatasvir
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The World Health Organization (WHO) has listed daclatasvir (DCV), symmetrical arene, as one of the essential medicines for human health. DCV manufacturing is usually carried out in a non-continuous or "batch" approach over multiple locations and is severely limited by long production times (3-10 days), resulting in non-affordability (highly expensive) and disruption of the potential chain supply. Here, we report the total process system including the development of a novel electro-flow reactor containing patterned electrodeposited Ni or Pt nanoparticles over a copper electrode for a C-C coupling reaction in a co-reductant/oxidant-free, ultra-fast process for symmetrical substituted/unsubstituted biphenyl synthesis. This method was further extended to a new generation commercial batch synthetic route for continuous flow ultra-fast daclatasvir synthesis in 33.2 min. We envisage that this micro-electro-flow reactor (μ-EFR) system platform will substantially enable advances in continuous-μ-flow fine chemical manufacturing, multistep reaction sequences, reaction devising equipment, and real-time extraction.
- Mahajan, Bhushan,Mujawar, Taufiqueahmed,Ghosh, Subhash,Pabbaraja, Srihari,Singh, Ajay K.
-
supporting information
p. 11852 - 11855
(2019/10/11)
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- Ligand-free palladium catalyzed Ullmann biaryl synthesis: 'Household' reagents and mild reaction conditions
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A palladium catalysed Ullmann biaryl synthesis has been developed using hydrazine hydrate as the reducing reagent at room temperature. The combination of Pd(OAc)2 and hydrazine hydrate works smoothly for the coupling of both electron-rich and electron-deficient aryl iodides, as well as hetero-aryl iodides, leading to a wide range of biaryls in good to excellent yields. The reaction requires only 1 mol% Pd(OAc)2 and the in situ generated palladium naoparticles are found to be active catalysts.
- Gong, Xinchi,Wu, Jie,Meng, Yunge,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
-
supporting information
p. 995 - 999
(2019/03/12)
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- Synergistic Activities in the Ullmann Coupling of Chloroarenes at Ambient Temperature by Pd-Supported Calcined Ferrocenated La2O3
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Novel palladium-doped nanoparticles have been explored to serve as the first metal oxide-derived heterogeneous catalyst for Ullmann reaction of chloroarenes under mild condition (34?°C). This heterogeneous catalyst exhibited high catalytic activity towards the Ullmann homocoupling of chloroarenes into a series of useful symmetrically biaryl products with good to excellent yields in the presence of ethanol and NaOH, thereby leading to green and economical Ullmann reaction. The produced nanoparticles were successfully characterized by various techniques including PXRD, XPS, HRTEM, SEM-EDS, BET, TGA techniques, elemental mapping analysis and ICP-OES. Interestingly, based on characterization and experimental data, a reasonable mechanism has been proposed. Also, the formation of aryl methyl ketone as a by-product has been further confirmed by isotopic labelling experiments that the acetyl moiety is derived from ethanol. Moreover, the catalyst was stable and could be easily reused up to 5 times under atmospheric air without suffering significant loss in catalytic activity.
- Chumkaeo, Peerapong,Poonsawat, Thinnaphat,Meechai, Titiya,Somsook, Ekasith
-
-
- Polyoxomolybdate based ionic-liquids as active catalysts for oxidative desulfurization of simulated diesel
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This work compares the stability and the catalytic efficiency of different ionic liquid phosphomolybdates ([BPy]3[PMo12O40] and [BMIM]3[PMo12O40]) with a cationic (propylpyridinium) functionalized mesoporous silica nanoparticle composite (PMo12O40@PPy-MSN). These were used as solid catalysts for the oxidative desulfurization of a multicomponent model diesel using hydrogen peroxide as oxidant and a polar immiscible extraction solvent. Ionic liquid ([BMIM][PF6] was successfully used as solvent to extract sulfur compounds from model diesel. The ionic liquid phosphomolybdates showed partial solubility in the ionic liquid phase, occurring some decomposition of their Keggin structure in the soluble reaction media, probably caused by their interaction with oxidant. On the other hand, the phosphomolybdate composite PMo12O40@PPy-MSN presented high structural stability and only negligible leaching occurrence after various consecutive reaction cycles. The model diesel was near complete desulfurized after 3 h and consecutive desulfurization cycles were performed without loss of activity. Therefore, the immobilization of Keggin phosphomolybdate structure [PMo12O40]3? using cationic propylpyridinium silica nanoparticle is an assertive strategy to produce stable and active heterogeneous catalysts.
- Mirante, Fatima,Gomes, Neide,Corvo, Marta C.,Gago, Sandra,Balula, Salete S.
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p. 762 - 770
(2019/07/17)
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- Aerobic Homocoupling of Arylboronic Acids Catalyzed by Regenerable Pd(II)@MIL-88B-NH2(Cr)
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A fast and operationally simple method for the aerobic homocoupling of arylboronic acids is described. The process is catalyzed by Pd(II) complexes supported on the metal-organic framework MIL-88B-NH2(Cr). The benefits of this approach include the use of a benign oxidant/solvent mixture at room temperature with catalytic amounts of base, easy recovery of the catalyst, and easy isolation of the products. Very high conversions and good yields were achieved for a variety of substrates, and the process was also carried out on a larger scale with the same efficiency. The catalyst was found to suffer deactivation due to progressive reduction and agglomeration of palladium into inactive metal clusters/particles. An innovative procedure for the oxidative redispersion and regeneration of the active Pd(II)@MOF species is presented.
- Valiente, Alejandro,Carrasco, Sergio,Sanz-Marco, Amparo,Tai, Cheuk-Wai,Bermejo Gómez, Antonio,Martín-Matute, Belén
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p. 3933 - 3940
(2019/05/22)
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- Ullmann reaction optimization within bitolyl and decafluorobiphenyl synthesis
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This article describes the investigation of the cross-coupling Ullman's reaction of aryl halides under various conditions to find optimal scalable method of biaryl synthesis and the development of preparative methods of synthesizing 3,3'-bitolyl and perfluorobipfenyl, which are valuable semi-products of organic synthesis.
- Kolotaev,Razinov,Khachatryan
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p. 993 - 999
(2018/05/28)
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- Nickel-Catalyzed Electrochemical Reductive Homocouplings of Aryl and Heteroaryl Halides: A Useful Route to Symmetrical Biaryls
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Due to their widespread presence in functional materials and pharmaceuticals, biaryls are of fundamental importance in organic chemistry. Methods for the synthesis of symmetrical biaryls generally involve both metallic reduction and transition-metal catalysis. In this work, we show that electroreduction can also constitute a very relevant way to achieve the nickel-catalyzed reductive synthesis of symmetrical biaryl compounds. Therefore, it is demonstrated that both aryl and heteroaryl halides undergo reductive coupling to furnish the corresponding symmetrical biaryls in fair to excellent yields. Reactions are performed under very mild conditions thus ensuring important functional group tolerance.
- Rahil, Rima,Sengmany, Stéphane,Le Gall, Erwan,Léonel, Eric
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p. 146 - 154
(2017/09/28)
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- Immobilization of an Aminobisphosphine–PdII Complex over Graphene Oxide: An Efficient and Reusable Catalyst for Suzuki–Miyaura, Ullmann Coupling and Cyanation Reactions
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The grafting of an aminobis(phosphine)–PdII complex (PNP–PdII) [PdCl2{(Ph2P)2N(CH2)3Si(OMe)3}] (2) on graphene oxide (GO) has been carried out by a condensation reaction between methoxysilane groups of 2 and hydroxyl groups of GO. The composite material was characterized by FTIR spectroscopy, solid-state 31P NMR spectroscopy, SEM, TEM, XPS and ICP-AES techniques. All these tools support the clean immobilization of compound 2 on GO. The composite material showed high catalytic activity in Suzuki–Miyaura, Ullmann coupling and cyanation reactions. The heterogeneity of the composite was confirmed by a hot filtration test. The immobilized PNP–PdII shows comparable activity to its homogeneous analogue 2. The recycling ability of the catalyst was examined for five consecutive runs, which showed little or no reduction in its catalytic efficiency.
- Sengupta, Debasish,Pandey, Madhusudan K.,Mondal, Dipanjan,Radhakrishna, Latchupatula,Balakrishna, Maravanji S.
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p. 3374 - 3383
(2018/05/08)
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- PRODUCTION METHOD OF 4,4'-DIIODO-3,3'-DIMETHYLBIPHENYL
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PROBLEM TO BE SOLVED: To provide a production method of 4,4'-diiodo-3,3'-dimethylbiphenyl, which is industrially excellent with high production efficiency and without using highly-toxic raw material. SOLUTION: Provided ia a production method of 4,4'-diiodo-3,3'-dimethylbiphenyl by reacting 3,3'-dimethylbiphenyl with an iodinated agent, comprising the steps of: subjecting 4,4'-diiodo-3,3'-dimethylbiphenyl to reactive crystallization in a reaction liquid; and subjecting deposited 4,4'-diiodo-3,3'-dimethylbiphenyl to solid-liquid separation. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
- -
-
Paragraph 0027; 0028
(2018/11/22)
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- Self-Assembly of Hierarchically Porous ZSM-5/SBA-16 with Different Morphologies and Its High Isomerization Performance for Hydrodesulfurization of Dibenzothiophene and 4,6-Dimethyldibenzothiophene
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ZSM-5/SBA-16 (ZS) composite materials with different morphologies were synthesized successfully. The series supports were utilized to prepare NiMo/ZS for dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) reactions. Series ZS supports and NiMo/ZS were well characterized to investigate their structure-property relationship. The NiMo/ZS catalyst (NiMo/ZS-3) with uniform morphology and well-ordered pore channels showed the maximum kHDS and TOF values of DBT and 4,6-DMDBT HDS. The kHDS value (13.9 × 10-4 mol g-1 h-1) of DBT over NiMo/ZS-3 was more than 2 times greater than that over the reference NiMo/ZS-M catalyst (5.5 × 10-4 mol g-1 h-1), 3 times greater than that over the NiMo/SBA-16 catalyst (4.4 × 10-4 mol g-1 h-1), and almost 4 times greater than that over the NiMo/ZSM-5 catalyst (3.5 × 10-4 mol g-1 h-1). Furthermore, the kHDS value (8.4 × 10-4 mol g-1 h-1) of 4,6-DMDBT over NiMo/ZS-3 was more than 3 times greater than that over the reference NiMo/ZS-M catalyst (2.8 × 10-4 mol g-1 h-1), more than 4 times greater than that over the NiMo/SBA-16 catalyst (1.7 × 10-4 mol g-1 h-1), and almost 5 times greater than that over the NiMo/ZSM-5 catalyst (1.6 × 10-4 mol g-1 h-1). The superior DBT and 4,6-DMDBT HDS performances were assigned to the uniform morphology, well-ordered pore channels, and high B/L ratio of the NiMo/ZS-3 catalyst and the suitable dispersion of the MoS2 active phases. HYD was the preferential route for DBT HDS, while ISO was the preferential route for 4,6-DMDBT HDS because of the high B/L ratio of NiMo/ZS-3. Moreover, the DBT and 4,6-DMDBT HDS reaction networks of the series NiMo/ZS are presented.
- Wang, Xilong,Mei, Jinlin,Zhao, Zhen,Zheng, Peng,Chen, Zhentao,Gao, Daowei,Fu, Jianye,Fan, Jiyuan,Duan, Aijun,Xu, Chunming
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p. 1891 - 1902
(2018/03/13)
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- A ligand free protocol using Cu(OAc)2@Mont K-10 as versatile reusable catalyst for efficient homocoupling of arylboronic acids for synthesis of symmetric biaryls
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Biaryls are an important class of organic compounds that occur in many natural products and they have a wide variety of applications in drugs, agrochemicals, dyes, semi-conductors, and asymmetric syntheses. A versatile, eco-friendly, recyclable, heterogeneous catalyst has been developed for the efficient synthesis of symmetric biaryls from aryl boronic acids. The developed protocol for homocoupling of aryl boronic acid to symmetric biaryls is based on copper acetate supported on acid activated Mont K-10 which is ligand free, mild, inexpensive and compatible with wide range of functional groups and exhibit excellent yields. The catalyst is characterised by FTIR, ESR, XRD, SEM-EDX, BET surface area measurement and the catalyst can be separated from the reaction mixture by simple centrifugation and reused upto five cycles without significant loss in activity.
- Rahman, Taskia,Borah, Geetika,Gogoi, Pradip K.
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p. 795 - 800
(2020/06/26)
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- Synthesis and characterization of a palladium(0) complex with cyclophosphazene bearing two diphenylphosphine ligands and application in Suzuki-Miyaura cross-coupling
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This paper describes the synthesis of a cyclophosphazene-based diphenylphosphine ligand and a new Pd(0) complex. Infrared spectroscopy (ATR-IR), ESI+-MS, 31P, 1H and 13C NMR, Raman, WD-XRF, ICP-OES and TGA analysis show the coordination of two palladium atoms per unit of cyclophosphazene. A semiempirical calculation method was employed to find the lowest energy structure among the possible ones and Density Functional Theory (DFT) was used to optimize the found structure and obtain its bond angles, dihedral angles, bond lengths, atomic distances, and to calculate the vibrational spectrum (PBE/def2-TZVP(-f)). The new Pd complex showed activity in Suzuki-Miyaura cross-coupling reactions with halobenzenes and phenylboronic acid, tolerating different functional groups.
- Silva, Maria das G. de O. e,Galuppo, Carolina,Tudisco, Bárbara C.,Oliveira Junior, Arnaldo G. de,Barrionuevo, Manoel V.F.,Abbehausen, Camilla,Buffon, Regina
-
supporting information
p. 259 - 267
(2018/06/26)
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- Palladium-mediated radical homocoupling reactions: A surface catalytic insight
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In this contribution, we report a palladium nanoparticle-promoted reductive homocoupling of haloarenes that proceeds efficiently to produce corresponding bis-aryls in moderate to excellent yields using relatively low catalyst loading (1 mol%), and exhibits broad functional group tolerance. This work sheds light on how the surface state of Pd(0) nanoparticles plays a crucial role in the reactivity of catalytic systems. Notably, the appropriate choice of palladium salts for the preparation of the preformed nanocatalysts was a key parameter having a major impact on the catalytic activity; thus, the effect of halide anions on the reactivity of the as-prepared palladium nanoparticles could be assessed, with iodide anions being capable of inhibiting the corresponding homocoupling reaction. The homocoupling reaction mechanism has been further studied by means of radical trap and electron paramagnetic resonance (EPR) experiments, revealing that the reaction proceeds via radical intermediates. Taking into account these data, a plausible reaction mechanism based on single-electron transfer processes on the palladium nanoparticle surface is discussed.
- Favier, Isabelle,Toro, Marie-Lou,Lecante, Pierre,Pla, Daniel,Gómez, Montserrat
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p. 4766 - 4773
(2018/09/29)
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- Palladium islands on iron oxide nanoparticles for hydrodesulfurization catalysis
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A four-fold increase in palladium (Pd) mass-based hydrodesulfurization (HDS) activity was achieved by depositing Pd species as nanosized islands on 12 nm colloidal iron oxide (FeOx) nanoparticles via the galvanic exchange reaction. The highest palladium dispersion was obtained at an optimal Pd/Fe molar ratio of 0.2, which decreased when the ratio increased. The improved dispersion was responsible for the enhanced catalytic activity per the total Pd amount in the HDS of 4,6-dimethyldibenzothiophene at 623 K and 3 MPa as compared to the iron-free Pd/Al2O3 catalyst. The lattice strain and modified electronic properties of the Pd islands suppressed deep hydrogenation to dimethylbicyclohexyl and changed the hydrocracking product distribution. Pd nanoparticles deposited on commercial Fe2O3 did not provide such an activity enhancement and catalyzed significant cracking. This study demonstrates that FeOx@Pd structures are a possible alternative to monometallic Pd catalysts with enhanced noble metal atom efficiency for ultra-deep HDS catalysis and points to their great potential to reduce the catalyst cost and move towards more earth-abundant catalytic materials.
- Mansouri, Ali,Semagina, Natalia
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p. 2323 - 2332
(2018/05/23)
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- Desulfurization of dibenzothiophene and dibenzothiophene sulfone via Suzuki–Miyaura type reaction: Direct access to o-terphenyls and polyphenyl derivatives
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The reactivity of dibenzothiophene (DBT) or dibenzothiophene sulfone (DBTO2) with a variety of phenylboronic acids was mediated by the nickel precursor [Ni(dippe)Cl2] in the presence of a base. The reaction was performed under relatively mild conditions (70–100 °C), in aqueous media. The study of the reactivity revealed the role of water as a hydrogen source and showed a competition between the desulfurization of the corresponding substrates via a hydrodesulfurization (HDS) or by a hydrodesulfurative cross-coupling (HDSCC) reaction. Furthermore, in the absence of water sulfur-free poly-phenylic compounds were obtained in good yields as a result of a Suzuki–Miyaura type reaction, being the main product in most of the cases the corresponding o-terphenyl derivative, these products are valuable building blocks in the synthesis of more complex materials.
- Gutiérrez-Ordaz, Rubén,García, Juventino J.
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p. 373 - 381
(2018/08/31)
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- Carbon-carbon bond forming reactions via Pd-catalyzed detellurative homocoupling of diorganyl tellurides
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A simple and highly efficient method for the constructions of Csp-Csp, Csp2-Csp2 and Csp3-Csp3 bonds is reported. The symmetrical diaryl tellurides undergo detellurative homocouplings to afford symmetrical biaryl products. The reactions are carried out at ambient temperature using PdCl2 as a catalyst in the presence of Ag2O and Na2CO3. Similarly, the detellurative homocouplings of dibenzyl telluride and bis(phenylethynyl)telluride give bibenzyl and the conjugated diyne, respectively.
- Zhang, Shaozhong,Kolluru, Lalitha,Vedula, Souseelya K.,Whippie, Drew,Jin, Jin
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p. 3594 - 3597
(2017/08/23)
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- OXIDATION OF METHYL-SUBSTITUTED BIPHENYL COMPOUNDS
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A process for oxidizing methyl-substituted biphenyl compounds comprises contacting a mixture comprising isomers of at least one methyl-substituted biphenyl compound with a source of oxygen, wherein the mixture comprises at least 20 wt% of isomer(s) having a methyl group at a 2-position or a 3-position on at least one benzene ring and at least 50 wt% of isomer(s) having a methyl group at a 4-position on at least one benzene ring, wherein said percentages are based on the total weight of the at least one methylbiphenyl compound in the mixture.
- -
-
Paragraph 0064-0066
(2017/11/04)
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- Hydrotalcite-supported Pd-Au nanocatalysts for Ullmann homocoupling reactions at low temperature
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Hydrotalcite-supported Pd-Au nanocatalysts were found to be efficient heterogeneous catalysts for Ullmann homocoupling reactions of aryl bromides or chlorides at 25 or 40 °C, which could be due to the ensemble effect and increased electron density of Pd sites on Pd-Au nanoparticles, and the assistant role of the hydrotalcite for the reversion of the catalytic active center, Pd(0).
- Wang, Jiang,Xu, Aiju,Jia, Meilin,Bai, Sagala,Cheng, Xiaodan,Zhaorigetu, Bao
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p. 1905 - 1908
(2017/03/09)
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- Rapid Ligand-Free Base-Accelerated Copper-Catalyzed Homocoupling Reaction of Arylboronic Acids
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A rapid, ligand-free, base-accelerated, copper-catalyzed homocoupling reaction of (het)arylboronic acids is presented. A -CuCl2·2H2O/Na2CO3-based catalyst enabled the formation of bi(het)aryl compounds by a homocoupling process in moderate to excellent yields (72-97%) within 15 minutes. A mechanism for the copper-catalyzed base-accelerated reaction is proposed.
- Cao, Ya-Nan,Tian, Xin-Chuan,Chen, Xing-Xiu,Yao, Yun-Xin,Gao, Feng,Zhou, Xian-Li
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supporting information
p. 601 - 606
(2017/03/11)
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- Amide-ligand-controlled highly para-selective arylation of monosubstituted simple arenes with arylboronic acids
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Pd-catalyzed highly para-selective arylations of monosubstituted simple arenes with arylboronic acids to widely existed biaryls have been developed. Inspired by requisite amide-directing groups in reported selective oxidative couplings, amide ligands, especially DMF, are designed and found to be critical for the selectivity control in current arylations.
- Luan, Yu-Xin,Zhang, Tao,Yao, Wei-Wei,Lu, Ke,Kong, Lu-Yao,Lin, Yu-Tong,Ye, Mengchun
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supporting information
p. 1786 - 1789
(2017/02/15)
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- An unexpected pathway for hydrodesulfurization of gazole over a CoMoS active phase supported on a mesoporous TiO2 catalyst
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Using dual mesoporous titania as a support, due to the presence of intrinsic Br?nsted acid sites, the main approach to 4,6-dimethylbenzothiophene (46DMDBT) hydrodesulfurization (HDS) becomes the direct desulfurization (DDS) route through isomerization and dismutation reactions, instead of the hydrogenation (HYD) pathway usually observed with a conventional promoted (by Ni or Co) MoS2/Al2O3 catalyst.
- Naboulsi,Felipe Linares Aponte,Lebeau,Brunet,Michelin,Bonne,Blin
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p. 2717 - 2720
(2017/03/10)
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- Gallium Modified HUSY Zeolite as an Effective Co-support for NiMo Hydrodesulfurization Catalyst and the Catalyst's High Isomerization Selectivity
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The effects of metal-modified acidic co-supports on the hydrodesulfurization (HDS) activity and isomerization selectivity of highly refractory organosulfur compounds such as 4,6-dimethyldibenzothiophene have been investigated. Y zeolite crystals with high Si/Al ratios and small crystallite sizes were successfully synthesized by a new hydrothermal synthesis approach. The synthesized Y zeolite crystals were ion-exchanged and stabilized. The prepared samples were then modified with different gallium contents using an impregnation method to adjust their acidity properties, and these modified samples were used as co-supports for NiMo sulfide HDS catalysts. The catalyst containing 10 wt.% zeolite Y modified by 2 wt.% gallium (NiMo/2GaY-ASA-A) exhibited the highest HDS activity, with 4,6-dimethyldibenzothiophene (4,6-DMDBT) conversion nearly double the rate of the catalyst without zeolite at 563 K, 4.0 MPa and liquid hourly space velocity (LHSV) of 40 h?1. NiMo/2GaY-ASA-A also exhibited superior isomerization ability, with 3,4′-DMBP, 4,4′DMBP, and 3,6-DMDBT as the main products, indicating that the isomerization pathway was the main reaction route over NiMo/2GaY-ASA-A. The superior catalytic performance is related to the synergistic effect of the proper amount of medium and strong Br?nsted acid sites. The compounds 3,6-DMDBT and 3,7-DMDBT (isomers of 4,6-DMDBT) and 3,4,6-TMDBT and tetra-methyl-DBT (transmethyl products) were detected simultaneously in the HDS product of 4,6-DMDBT for the first time over NiMo/GaY-ASA-A catalysts. Finally, a new reaction network over NiMo/2GaY-ASA-A was proposed.
- Zhou, Wenwu,Zhou, Yasong,Wei, Qiang,Du, Lin,Ding, Sijia,Jiang, Shujiao,Zhang, Yanan,Zhang, Qing
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p. 9369 - 9382
(2017/07/17)
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- Homocoupling of heteroaryl/aryl/alkyl Grignard reagents: I2-promoted, or Ni- or Pd- or Cu- or nano-Fe-based salt catalyzed
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Five efficient processes for the homo-coupling of various Grignard reagents including aryl, heteroaryl and aliphatic ones in the presence of I2, Pd(OAc)2, Ni(OAc)2, CuI, and nano-Fe3O4 were developed, respectively.
- Li, Xing,Li, Dongjun,Li, Yingjun,Chang, Honghong,Gao, Wenchao,Wei, Wenlong
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p. 86998 - 87002
(2016/09/23)
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- Anionic porous polymers with tunable structures and catalytic properties
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A series of boron-containing conjugated microporous polymers with hierarchical porous structures have been readily prepared via typical transition metal-catalyzed coupling reactions. The distribution of micro- and mesopores in the networks as well as the specific surface areas are tunable via tailoring the structures of the building blocks. The distinct capability of the resulting Lewis acid-based neutral porous polymers to selectively capture fluoride ions provides a high-efficiency conversion into stable anionic porous polymers. For the first time, fluoride anion binding to boron atoms in a solid sample was essentially characterized by solid-state 11B MAS NMR spectroscopy, clearly revealing such an efficient conversion from a neutral network to a negatively charged one only through Lewis acid-base adduct formation. Upon a simple ion-exchange process, various heavy metal cations were facile to be loaded into the networks of the anionic porous polymers. Furthermore, the cobalt(ii)-loaded porous polymers were shown to promote the stoichiometric homocoupling reactions of the different aryl Grignard regents, and exert distinct size selectivities for the homocoupling products, highly dependent on their porous structures. Such a successful loading strategy might be used for design and synthesis of new types of zeolite-like porous polymers with desirable catalytic properties for a certain organic transformation, as well as other functional materials.
- Zhao, Wuxue,Zhang, Fan,Yang, Lingyun,Bi, Shuai,Wu, Dongqing,Yao, Yefeng,Wagner, Manfred,Graf, Robert,Hansen, Michael Ryan,Zhuang, Xiaodong,Feng, Xinliang
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p. 15162 - 15168
(2016/10/13)
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- Palladium Nanoparticle Size Effect in Hydrodesulfurization of 4,6-Dimethyldibenzothiophene (4,6-DMDBT)
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Pd nanoparticle size sensitivity of 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization was investigated by using 4, 8, 13, and 87 nm particles and was compared with the sulfur-free and sulfur-inhibited hydrogenation of 3,3-dimethylbiphenyl, which is a product of direct desulfurization of 4,6-DMDBT. The smallest 4 nm particles provided unprecedented (for Pd at 5 MPa and 300 °C) direct desulfurization selectivity of 20 % at 40 % conversion because of the reduced contribution of the hydrogenation path. The 4 nm particles were poisoned by the adsorbed sulfur to the greatest extent. The optimal size, providing the highest Pd mass-based yield of the desulfurized products, was found to be 8 nm. The catalyst with 87 nm particles was based on Pd nanocubes with the lowest edge/terrace surface atom ratio and large terraces and this showed the lowest sulfur extraction from both 4,6-DMDBT and sulfurous intermediates as a result of the low availability of edge atoms for a perpendicular sigma-mode adsorption through the lone pair of the sulfur atom.
- Shen, Jing,Semagina, Natalia
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p. 2565 - 2571
(2016/08/25)
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- Deep hydrodesulfurization of FCC gasoline and gas oil cuts: Comparison of CO effect, a by-product from biomass
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Regarding the composition of the various feedstocks which should be hydrotreated in order to obtain fuels with amount of sulfur less than 10 wt ppm, we have shown that the presence of traces of CO, a by-product from lignocellulosic biomass feedstock conversion, inhibited the transformation of model compounds representative of FCC gasolines and gas oils over CoMo-based sulfide catalysts. Thus, this effect is more significant in the presence of 2-methylthiophene and 2,3-dimethylbut-2-ene representative of a FCC gasoline than in the presence of dibenzothiophene and 4,6-dimethyldibenzothiophene representative of a straight run gas oil, even if the operating conditions are not the same. This effect is attributed to phenomena of competitive adsorption between sulfur compounds, alkenes and CO on the catalyst surface.
- Pelardy, Florian,Philippe, Maxime,Richard, Frédéric,Daudin, Antoine,Devers, élodie,Hudebine, Damien,Brunet, Sylvette
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p. 1266 - 1275
(2016/10/13)
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