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Rational Design of Zinc/Zeolite Catalyst: Selective Formation of p-Xylene from Methanol to Aromatics Reaction
The production of p-xylene from the methanol to aromatics (MTA) reaction is challenging. The catalytic stability, which is inversely proportional to the particle size of the zeolite, is not always compatible with p-xylene selectivity, which is inversely proportional to the external acid sites. In this study, based on a nano-sized zeolite, we designed hollow triple-shelled Zn/MFI single crystals using the ultra-dilute liquid-phase growth technique. The obtained composites possessed one ZSM-5 layer (≈30 nm) in the middle and two silicalite-1 layers (≈20 nm) epitaxially grown on two sides of ZSM-5, which exhibited a considerably long lifetime (100 % methanol conversion >40 h) as well as an enhanced shape selectivity of p-xylene (>35 %) with a p-xylene/xylene ratio of ≈90 %. Importantly, using this sandwich-like zeolite structure, we directly imaged the Zn species in the micropores of only the ZSM-5 layer and further determined the specific structure and anchor location of the Zn species.
Chen, Biaohua,Chen, Congmei,Chen, Xiao,Hou, Yilin,Hu, Xiaomin,Li, Jing,Qian, Weizhong,Sun, Wenjing,Wang, Ning,Yang, Yifeng,Zhang, Lan
supporting information

(2022/02/16)

Protodesilylation of Arylsilanes by Visible-Light Photocatalysis
The first visible-light-mediated photocatalytic, metal- and base-free protodesilylation of arylsilanes is presented. The C(sp2)-Si bond cleavage process is catalyzed by a 5 mol % loading of a commercially available acridinium salt upon blue-light irradiation. Two simple approaches have been identified employing either aerobic or hydrogen atom transfer cocatalytic conditions, which enable the efficient and selective desilylation of a broad variety of simple and complex arylsilanes under mild conditions.
García Manche?o, Olga,Kuhlmann, Jan H.,Uygur, Mustafa
supporting information
p. 1689 - 1694
(2022/03/14)

Photochemical and electrochemical C-N borylation of arylhydrazines
The C-N borylation of arylhydrazine hydrochlorides with bis(pinacolato)diboron was achieved under photochemical and electrochemical conditions, respectively. This novel and scalable transformation provides two efficient and mild transition-metal-free synt
Du, Linlin,Sun, Li,Zhang, Hua
supporting information
p. 1716 - 1719
(2022/02/21)

One-Pass Conversion of Benzene and Syngas to Alkylbenzenes by Cu–ZnO–Al2O3 and ZSM-5 Relay
Alkylbenzenes have a wide range of uses and are the most demanded aromatic chemicals. The finite petroleum resources compels the development of production of alkylbenzenes by non-petroleum routes. One-pass selective conversion of benzene and syngas to alkylbenzenes is a promising alternative coal chemical engineering route, yet it still faces challenge to industrialized applications owing to low conversion of benzene and syngas. Here we presented a Cu–ZnO–Al2O3/ZSM-5 bifunctional catalyst which realizes one-pass conversion of benzene and syngas to alkylbenzenes with high efficiency. This bifunctional catalyst exhibited high benzene conversion (benzene conversion of 50.7%), CO conversion (CO conversion of 55.0%) and C7&C8 aromatics total yield (C7&C8 total yield of 45.0%). Characterizations and catalytic performance evaluations revealed that ZSM-5 with well-regulated acidity, as a vital part of this Cu–ZnO–Al2O3/ZSM-5 bifunctional catalyst, substantially contributed to its performance for the alkylbenzenes one-pass synthesis from benzene and syngas due to depress methanol-to-olefins (MTO) reaction. Furthermore, matching of the mass ratio of two active components in the dual-function catalyst and the temperature of methanol synthesis with benzene alkylation reactions can effectively depress the formation of unwanted by-products and guarantee the high performance of tandem reactions. Graphic Abstract: [Figure not available: see fulltext.]
Dong, Jinxiang,Ge, Hui,Han, Tengfei,Li, Xuekuan,Liu, Jianchao,Xu, Hong,Zhou, Ligong
(2021/05/21)

Metal-Free Heterogeneous Semiconductor for Visible-Light Photocatalytic Decarboxylation of Carboxylic Acids
A suitable protocol for the photocatalytic decarboxylation of carboxylic acids was developed with metal-free ceramic boron carbon nitrides (BCN). With visible light irradiation, BCN oxidize carboxylic acids to give carbon-centered radicals, which were trapped by hydrogen atom donors or employed in the construction of the carbon-carbon bond. In this system, both (hetero)aromatic and aliphatic acids proceed the decarboxylation smoothly, and C-H, C-D, and C-C bonds are formed in moderate to high yields (35 examples, yield up to 93%). Control experiments support a radical process, and isotopic experiments show that methanol is employed as the hydrogen atom donor. Recycle tests and gram-scale reaction elucidate the practicability of the heterogeneous ceramic BCN photoredox system. It provides an alternative to homogeneous catalysts in the valuable carbon radical intermediates formation. Moreover, the metal-free system is also applicable to late-stage functionalization of anti-inflammatory drugs, such as naproxen and ibuprofen, which enrich the chemical toolbox.
Shi, Jiale,Yuan, Tao,Zheng, Meifang,Wang, Xinchen
p. 3040 - 3047
(2021/03/09)

Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
supporting information
p. 8108 - 8115
(2021/10/29)

Metal-Free Photoredox-Catalyzed Hydrodefluorination of Fluoroarenes Utilizing Amide Solvent as Reductant
A metal-free photoredox-catalyzed hydrodefluorination of fluoroarenes was achieved by using N,N,N’,N’-tetramethyl-para-phenylenediamine (1) as a strong photoreduction catalyst. This reaction was applicable not only to electron-rich monofluoroarenes but also to polyfluoroarenes to afford non-fluorinated arenes. The experimental mechanistic studies indicated that the amide solvent NMP plays an important role for regeneration of the photocatalyst, enabling additive-free photoreduction catalysis.
Toriumi, Naoyuki,Yamashita, Kazuya,Iwasawa, Nobuharu
supporting information
p. 12635 - 12641
(2021/08/03)

Carbon-Halogen Bond Activation with Powerful Heavy Alkaline Earth Metal Hydrides
Reaction of [(DIPePBDI)SrH]2 with C6H5X (X=Cl, Br, I) led to hydride-halogenide exchange (DIPePBDI=HC[(Me)CN-2,6-(3-pentyl)phenyl]2). Conversion rates increase with increasing halogen size (FDIPePBDI)SrH]2 with C6H5F was slow and ill-defined but addition of C6H4F2 gave smooth hydride-fluoride exchange. After addition of THF the full range of Sr halogenides was structurally characterized: [(DIPePBDI)SrX ? THF]2 (X=F, Cl, Br, I). Mixtures of AeN“2 and PhSiH3 in situ formed less defined but more robust Ae metal hydride clusters (AexN”yHz, Ae=Ca, Sr, Ba and N“=N(SiMe3)2) which are able to hydrodefluorinate C6H5F. Conversion rates increase with increasing metal size (Ca2/PhSiH3 mixtures also converted SF6 at room temperature to give undefined decomposition products. Addition of Me6Tren to a SrN“2/PhSiH3 led to crystallization of [Sr6N”2H9 ? (Me6Tren)3+][SrN“3?]; Me6Tren=tris[2-(dimethylamino)ethyl]amine). After hydrodefluorination, Sr6N”4F8 ? (Me6Tren)2 was formed and structurally characterized. Dissolution in THF led to cluster growth and the larger cluster Sr16N“8F24 ? (THF)12 is structurally characterized. DFT calculations support that hydrodehalogenation of halobenzenes follows a concerted nucleophilic aromatic substitution mechanism (cSNAr).
Harder, Sjoerd,Knüpfer, Christian,Langer, Jens,Mai, Jonathan,R?sch, Bastian,Wiesinger, Michael
p. 3731 - 3741
(2021/08/23)

Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
Substantial effort is currently being devoted to obtaining photoredox catalysts with high redox power. Yet, it remains challenging to apply the currently established methods to the activation of bonds with high bond dissociation energy and to substrates with high reduction potentials. Herein, we introduce a novel photocatalytic strategy for the activation of inert substituted arenes for aryl borylation by using thiolate as a catalyst. This catalytic system exhibits strong reducing ability and engages non-activated Caryl–F, Caryl–X, Caryl–O, Caryl–N, and Caryl–S bonds in productive radical borylation reactions, thus expanding the available aryl radical precursor scope. Despite its high reducing power, the method has a broad substrate scope and good functional-group tolerance. Spectroscopic investigations and control experiments suggest the formation of a charge-transfer complex as the key step to activate the substrates.
K?nig, Burkhard,Wang, Hua,Wang, Shun
p. 1653 - 1665
(2021/06/17)

Fabrication of a core-shell MFI?TON material and its enhanced catalytic performance for toluene alkylation
Core-shell MFI?TON composites were designed and synthesized as a highly shape-selective catalyst for toluene alkylation with methanol by passivating the nonselective acid sites and tuning the diffusion behavior. The synthesis parameters were comprehensively investigated, indicating the importance of the Si/Al ratio compatibility of the ZSM-5 and ZSM-22 components on the formation of a core-shell structure. The synthesis process was systemically traced, which allowed the formulation of a crystallization mechanism involving the oriented crystal growth and selective fusion steps during the secondary crystallization. As a result, the MFI zeolites as the core were fully covered by the TON zeolites as the shell, yielding spherical morphology. When applied to toluene alkylation with methanol, the core-shell MFI?TON composite exhibited significantly improved para-xylene selectivity in comparison with the original, unattached, and physically mixed catalysts. The enhanced catalytic behaviors of the core-shell MFI?TON composite could be ascribed to the effective suppression of para-xylene isomerization as a result of the passivated acid sites on the external surface and the improved diffusion time and distance for the intermediates inside the channels due to the unique structure. The synthesis method for the MFI?TON composite described herein may provide a generic platform for the design of core-shell zeolites with potentially broader applicability to other porous materials with advanced applications.
Chen, Huimin,Chen, Zhiqiang,Li, Yong-Wang,Liu, Suyao,Ren, Jie,Wen, Xiaodong,Yang, Yong,Zhang, Huaike,Zhang, Liwei
p. 1281 - 1291
(2020/03/24)

Visible-Light-Induced, Base-Promoted Transition-Metal-Free Dehalogenation of Aryl Fluorides, Chlorides, Bromides, and Iodides
We report a simple and efficient visible-light-induced transition-metal-free hydrogenation of aryl halides. The combined visible light and base system is used to initiate the desired radical-mediated hydrogenation. A variety of aryl fluorides, chlorides, bromides, and iodides could be reduced to the corresponding (hetero)arenes with excellent yields under mild conditions. Various functional groups and other heterocyclic compounds are tolerated.
Ding, Ting-Hui,Qu, Jian-Ping,Kang, Yan-Biao
supporting information
p. 3084 - 3088
(2020/04/10)

Effects of steam on toluene hydrogenation over a Ni catalyst
The catalytic toluene hydrogenation over Ni/SiO2 was carried out using H2 or a H2/H2O mixture. The toluene conversion and MCH selectivity were evaluated under partial steam pressures 0?10 kPa, at H2/t
Atsumi, Ryosuke,Kobayashi, Keisuke,Xieli, Cui,Nanba, Tetsuya,Matsumoto, Hideyuki,Matsuda, Keigo,Tsujimura, Taku
(2019/12/23)

METHOD FOR AROMATIZATION OF LIGHT ALKANES
A method for aromatization of light alkanes, comprising: subjecting the light alkanes to dehydroaromatization reaction in the presence of aromatization catalysts including carriers and metal active components supported on the carriers, the metal active components include platinum, the carriers include zeolites and binders, and at least 80 wt. % of the metal active components are distributed on the zeolites. The method of the present disclosure may increase yield of the target product—aromatic hydrocarbons, and the regenerated catalyst can still maintain high catalytic performance. In addition, the method of the present disclosure can meet the requirements of industrial applications.
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(2020/07/16)

Visible-Light-Induced Ni-Catalyzed Radical Borylation of Chloroarenes
A highly selective and general photoinduced C-Cl borylation protocol that employs [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the radical borylation of chloroarenes is reported. This photoinduced system operates with visible light (400 nm) and achieves borylation of a wide range of chloroarenes with B2pin2 at room temperature in excellent yields and with high selectivity, thereby demonstrating its broad utility and functional group tolerance. Mechanistic investigations suggest that the borylation reactions proceed via a radical process. EPR studies demonstrate that [Ni(IMes)2] undergoes very fast chlorine atom abstraction from aryl chlorides to give [NiI(IMes)2Cl] and aryl radicals. Control experiments indicate that light promotes the reaction of [NiI(IMes)2Cl] with aryl chlorides generating additional aryl radicals and [NiII(IMes)2Cl2]. The aryl radicals react with an anionic sp2-sp3 diborane [B2pin2(OMe)]- formed from B2pin2 and KOMe to yield the corresponding borylation product and the [Bpin(OMe)]?- radical anion, which reduces [NiII(IMes)2Cl2] under irradiation to regenerate [NiI(IMes)2Cl] and [Ni(IMes)2] for the next catalytic cycle.
Tian, Ya-Ming,Guo, Xiao-Ning,Krummenacher, Ivo,Wu, Zhu,Nitsch, J?rn,Braunschweig, Holger,Radius, Udo,Marder, Todd B.
supporting information
p. 18231 - 18242
(2020/11/02)

The Selective Conversion of Methyl and Ethyl Acetate to High Content Alkyl Aromatic Hydrocarbons over H-ZSM5
Abstract: This research is devoted to a catalytic process using the H-ZSM5 catalyst for the conversion of methyl and ethyl acetate to hydrocarbon aromatics. These reactions are carried out in a fixed bed reactor under atmospheric pressure at 370°C. The distribution of products was measured by GC-Mass spectrometer. The variation of weight hourly space velocity (WHSV) on the conversion of these esters to aromatic hydrocarbons showed a significant effect on carbon distribution. The deactivation catalyst by time was monitored using product selectivity and conversion. The production of alkyl and poly alkyl aromatic compounds was formed under controlled conditions. The advantages of these methods are the formation of a higher concentration of octane number booster poly alkyl aromatic compounds (mono-aromatics) from esters as starting materials. Moreover, the catalyst lifetime on stream was investigated and exhibited longer catalyst lifetime for ethyl acetate conversion than methyl acetate.
Dabbagh, H. A.,Hassanpour, J.
p. 1284 - 1290
(2020/12/02)

ZnFe-LDH/GO nanocomposite coated on the glass support as a highly efficient catalyst for visible light photodegradation of an emerging pollutant
This study reports the fabrication of ZnFe-layered double hydroxides with sulfate-intercalated anion (ZnFe-SO4-LDH) modified with graphene oxide (GO) by chemical co-precipitation method. They were then coated on the glass substrates (denoted as ZnFe-LDH/GO/GS). The XRD, SEM, EDX, X-ray Dot-mapping, FTIR, AFM, UV–Vis DRS, and PL analyses were used for the characterization of the as-synthesized sample. The photocatalytic implementation of the as-prepared photocatalyst was scrutinized for the degradation of phenazopyridine hydrochloride (PhP) from the solution under visible light irradiation. The prepared photocatalyst showed photocatalytic performance of elimination PhP, the degraded rate of pollutant could reach 60.01% in 150 min of photocatalysis process under the optimum conditions: initial PhP concentration of 15 mg/L, pH of 8 (natural pH), and 3 photocatalysts plates. The addition of 1 mmol/L of potassium persulfate (k2S2O8) caused the degradation efficiency of 93.95% within the 150 min of photocatalytic process. Trapping experiments indicated the influence order of O2 ?· > [rad]OH > h+ for the ROSs present in decomposition. The transformation of five intermediates of PhP produced in the photocatalytic degradation process was identified by the GC–MS technique. 60% COD removal efficiency was achieved after 300 min of photocatalytic reaction confirming mineralization of the PhP solution. Finally, a reusability test of ZnFe-LDH/GO/GS photocatalyst in the PhP degradation revealed that almost 12% drop occurred after five successive cycles.
Motlagh, Parisa Yekan,Khataee, Alireza,Hassani, Aydin,Sadeghi Rad, Tannaz
(2020/01/29)

Synthesized high-silica hierarchical porous ZSM-5 and optimization of its reaction conditions in benzene alkylation with methanol
In our present work, the high-silica hierarchical porous ZSM-5 with appropriate Br?nsted acidity and hierarchical porous structure was synthesized by sol-gel method for continuously catalytic conversion of benzene alkylation with methanol to xylene. The effects of temperature, pressure, benzene/methanol molar ratio and weight hour space velocity (WHSV) on the catalytic performance of the catalyst were investigated as well. As a result, the high-silica hierarchical porous ZSM-5 showed great performance as the yield of xylene was up to 41.1% under the optimum reaction conditions (500 °C, 0.1 MPa, Mbenzene/Mmethanol = 1:1.5 and WHSV = 4 h?1), while the selectivity to by-product, ethylbenzene, was well suppressed (below 0.1%). In addition, the catalyst structure and properties were characterized by the means of XRD, IR, TPD, SEM, TEM and N2 physical adsorption technologies.
Rui, Jiayao,Lyu, Jinghui,Hu, Hualei,Zhang, Qunfeng,Wang, Qingtao,Li, Xiaonian
p. 757 - 761
(2018/11/23)

Chemical Imaging of the Binder-Dependent Coke Formation in Zeolite-Based Catalyst Bodies During the Transalkylation of Aromatics
The choice of binder material, added to a zeolite-based catalyst body, can significantly influence the catalyst performance during a reaction, i. e. its deactivation and selectivity. In this work the influence of the binder in catalyst extrudates on the formation of hydrocarbon deposits was explored during the transalkylation of toluene with 1,2,4-trimethylbenzene (1,2,4-TMB). Using in situ UV-vis micro-spectroscopy and ex situ confocal fluorescence microscopy approach, coke species were revealed to predominantly form on the rim of zeolite crystals within Al2O3-bound extrudates. It was found that this was due to Al migration between the zeolite crystals and the Al2O3-binder creating additional acid sites near the zeolite external surface. In contrast, minimal isomerization of 1,2,4-TMB in the SiO2-bound extrudate allowed greater access to the zeolite internal pore network, creating a more homogeneous coke distribution throughout the zeolite crystals.
Verkleij, Suzanna P.,Whiting, Gareth T.,Pieper, Denise,Parres Esclapez, Sonia,Li, Shiwen,Mertens, Machteld M.,Janssen, Marcel,Bons, Anton-Jan,Burgers, Martijn,Weckhuysen, Bert M.
p. 4788 - 4796
(2019/09/17)

Transition metal-free hydrodefluorination of acid fluorides and organofluorines by Ph3GeH promoted by catalytic[Ph3C][B(C6F5)4]
It has been shown that the germane Ph3GeH converts aryl and aliphatic acid fluorides directly to their corresponding aldehydes without over-reduction via the conversion of Ph3GeH to the germylium cation[Ph3Ge]+ by a catalytic amount of the tritylium salt[Ph3C][B(C6F5)4]. Here, no transition metal catalyst is required and there is no decarbonylation of the acid fluoride, which are advantages over existing methods. The fluorine atoms can also be abstracted from organofluorine compounds using this method.
Hayatifar, Ardalan,Borrego, Alejandro,Bosek, David,Czarnecki, Matthew,Derocher, Gabriel,Kuplicki, Adam,Lytle, Erik,Padilla, Jonas,Paroly, Charles,Tubay, Gillian,Vyletel, Jackson,Weinert, Charles S.
supporting information
p. 10852 - 10855
(2019/09/18)

Insight into the impact of Al distribution on the catalytic performance of 1-octene aromatization over ZSM-5 zeolite
To correlate the relationship between the Al distribution and the catalytic performance of long-chain olefin aromatization, several ZSM-5 zeolites with different Al locations and proximities were prepared via adjusting the hydrothermal synthesis condition
Zhang, Liwei,Zhang, Huaike,Chen, Zhiqiang,Ning, Qiang,Liu, Suyao,Ren, Jie,Wen, Xiaodong,Li, Yong-Wang
p. 7034 - 7044
(2019/12/24)

Surface Modification of a Supported Pt Catalyst Using Ionic Liquids for Selective Hydrodeoxygenation of Phenols into Arenes under Mild Conditions
The selective and efficient removal of oxygenated groups from lignin-derived phenols is a critical challenge to utilize lignin as a source for renewable aromatic chemicals. This report describes how surface modification of a zeolite-supported Pt catalyst using ionic liquids (ILs) remarkably increases selectivity for the hydrodeoxygenation (HDO) of phenols into arenes under mild reaction conditions using atmospheric pressure H2. Unmodified Pt/H-ZSM-5 converts phenols into aliphatic species as the major products along with a slight amount of arenes (10 % selectivity). In contrast, the catalyst modified with an IL, 1-butyl-3-methylimidazolium triflate, keeps up to 76 % selectivity for arenes even at a nearly complete conversion of phenols. The IL on the surface of Pt catalyst may offer the adsorption of phenols in an edge-to-face manner onto the surface, thus accelerating the HDO without the ring hydrogenation.
Ohta, Hidetoshi,Tobayashi, Kanako,Kuroo, Akihiro,Nakatsuka, Mao,Kobayashi, Hirokazu,Fukuoka, Atsushi,Hamasaka, Go,Uozumi, Yasuhiro,Murayama, Haruno,Tokunaga, Makoto,Hayashi, Minoru
supporting information
p. 14762 - 14766
(2019/11/13)

Surface-Passivated Hierarchically Structured ZSM5 Zeolites: High-Performance Shape-Selective Catalysts for para-Xylene Production
Hierarchically structured ZSM-5 zeolites (HSZ) were synthesized and used as high-performance catalysts for para-xylene (p-X) production by tuning their pore structures and external surface acidity, which was achieved by two independent passivation approaches: dealumination in oxalic acid solution and chemical liquid deposition of tetra-ethoxysilane (CLD of TEOS). The mesoporous structures of HSZ were well-preserved after dealumination or CLD of TEOS, and the external surfaces of HSZ were passivated significantly. Compared to dealumination, CLD is more efficient because not only the external surface could be passivated, but also the pore-openings of HSZ had been effectively narrowed, which both favored the enhancement of product p-X selectivity in ortho-xylene (o-X) isomerization. The constraint index (CI) of as-synthesized catalysts derived from the competitive reactions of ethylbenzene (EB) dealkylation and meta-xylene (m-X) isomerization and gravimetric adsorption measurements were introduced to investigate the extent of pore-narrowing by CLD of TEOS. Benefitting from the auxiliary mesopores and surface-passivation treatments, the optimized catalyst HSZ(Si0.5) showed remarkably enhanced catalytic activity over the microporous ZSM-5 counterpart in the model reaction of o-X isomerization.
Lv, Jian,Hua, Zile,Zhou, Jian,Liu, Zhicheng,Guo, Hangle,Shi, Jianlin
p. 2278 - 2284
(2018/03/13)

A Zeolite Family Nonjointly Built from the 1,3-Stellated Cubic Building Unit
From a technological point of view, the synthesis of new high-silica zeolites is of prime importance owing to their high potential as industrial catalysts and catalyst supports. Two such materials have been synthesized which are made up of the 1,3-stellated cubic unit (hexahedral ([4254]) bre unit) as a secondary building unit, with the aid of existing imidazolium-based structure-directing agents under “excess fluoride” conditions. One of them, denoted PST-21, is the first aluminosilicate zeolite consisting of 9-ring apertures solely; it displays exceptional activity towards steering the skeletal isomerization of 1-butene to isobutene and bridges the gap between small- and medium-pore structures. A series of hypothetical structures are also described that are nonjointly built from the bre unit; all of these structures are chemically feasible and will thus be helpful in designing the synthesis of novel zeolites containing 9-ring and/or 10-ring channels.
Jo, Donghui,Park, Gi Tae,Shin, Jiho,Hong, Suk Bong
supporting information
p. 2199 - 2203
(2018/02/06)

Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds
Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
Stache, Erin E.,Ertel, Alyssa B.,Rovis, Tomislav,Doyle, Abigail G.
p. 11134 - 11139
(2018/11/21)

Pushing the Limits on Metal-Organic Frameworks as a Catalyst Support: NU-1000 Supported Tungsten Catalysts for o-Xylene Isomerization and Disproportionation
Acid-catalyzed skeletal C-C bond isomerizations are important benchmark reactions for the petrochemical industries. Among those, o-xylene isomerization/disproportionation is a probe reaction for strong Br?nsted acid catalysis, and it is also sensitive to the local acid site density and pore topology. Here, we report on the use of phosphotungstic acid (PTA) encapsulated within NU-1000, a Zr-based metal-organic framework (MOF), as a catalyst for o-xylene isomerization at 523 K. Extended X-ray absorption fine structure (EXAFS), 31P NMR, N2 physisorption, and X-ray diffraction (XRD) show that the catalyst is structurally stable with time-on-stream and that WOx clusters are necessary for detectable rates, consistent with conventional catalysts for the reaction. PTA and framework stability under these aggressive conditions requires maximal loading of PTA within the NU-1000 framework; materials with lower PTA loading lost structural integrity under the reaction conditions. Initial reaction rates over the NU-1000-supported catalyst were comparable to a control WOx-ZrO2, but the NU-1000 composite material was unusually active toward the transmethylation pathway that requires two adjacent active sites in a confined pore, as created when PTA is confined in NU-1000. This work shows the promise of metal-organic framework topologies in giving access to unique reactivity, even for aggressive reactions such as hydrocarbon isomerization.
Ahn, Sol,Nauert, Scott L.,Buru, Cassandra T.,Rimoldi, Martino,Choi, Hyeju,Schweitzer, Neil M.,Hupp, Joseph T.,Farha, Omar K.,Notestein, Justin M.
supporting information
p. 8535 - 8543
(2018/06/25)

Low Temperature Direct Conversion of Methane using a Solid Superacid
The direct conversion of methane to higher hydrocarbons and hydrogen can be catalyzed using “superacids”: nCH4→CnHm+xH2. The first report of catalytic oligomerization of methane using superacids was that of Olah et al., who demonstrated the superacidity of FSO3H?SbF5, which is a liquid. More recently, Vasireddy et al. showed that gas-phase HBr/AlBr3 was an active superacid. The only reported solid superacid for methane oligomerization is sulfated zirconia (SZ). Here, we report a new class of Br-based solid superacids, AlBrx/H-ZSM-5 (“ABZ-5”, x=1 or 2). ABZ-5 is based on gas-phase HBr/AlBr3, with the objective of synthesizing a heterogeneous analogue of the gas-phase superacid HBr/AlBr3. The results show that ABZ-5 is significantly more active than SZ. Perhaps more significantly, results here show methane conversions of ～1 % at 300 °C using ABZ-5. By comparison with SZ, 350 °C is the lowest temperature reported in the literature at which measurable conversions are shown, and the corresponding methane conversions were a solid superacid catalyst, AlBrx/H-ZSM-5. This solid catalyst is synthesized using a vapor-phase process in which AlBr3 vapor is grafted on to solid H-SZM-5. This catalyst is characterized using NH3-TPD, XRD, and DRIFTS. Hydrocarbon products observed in the temperature range of 200–400 °C include both C2–C6 hydrocarbons and aromatics.
Kanitkar, Swarom,Carter, James H.,Hutchings, Graham J.,Ding, Kunlun,Spivey, James J.
p. 5033 - 5038
(2018/10/24)

Catalyst, preparation method thereof, and application of same in pyrolysis reduction of aryl ether compounds
The invention belongs to the technical field of catalysts and particularly relates to: a catalyst, a preparation method thereof, and an application of same in pyrolysis reduction of aryl ether compounds. The catalyst employs nickel and nickel oxide as active sites and alumina as a carrier and is produced through high-temperature reduction with hydrogen. The catalyst can be used for catalyzing reactions of pyrolying aryl ether compounds with n-butanol, iso-propanol, benzyl alcohol, ethylene glycol and the like as hydrogen sources. The catalyst has simple preparation method and great stability,can be recycled for more than 16 times, and has excellent industrial application prospect.
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(2018/10/11)

Palladium-Catalyzed Chemoselective Protodecarboxylation of Polyenoic Acids
Conditions for the first palladium-catalyzed chemoselective protodecarboxylation of polyenoic acids to give the desired polyenes in good yields are presented. The reactions proceed under mild conditions using either a Pd(0) or Pd(II) catalyst and tolerate a variety of aryl and aliphatic substitutions. Unique aspects of the reaction include the requirement of phosphines, water, and a polyene adjacent to the carboxylic acid.
Al-Huniti, Mohammed H.,Perez, Mark A.,Garr, Matthew K.,Croatt, Mitchell P.
supporting information
p. 7375 - 7379
(2019/01/03)

Palladium/Rhodium Cooperative Catalysis for the Production of Aryl Aldehydes and Their Deuterated Analogues Using the Water–Gas Shift Reaction
A novel Pd/Rh dual-metallic cooperative catalytic process has been developed to effect the reductive carbonylation of aryl halides in moderate to good yield. In this reaction, water is the hydride source, and CO serves both as the carbonyl source and the terminal reductant through the water–gas shift reaction. The catalytic generation of the Rh hydride allows for the selective formation of highly hindered aryl aldehydes that are inaccessible through previously reported reductive carbonylation protocols. Moreover, aldehydes with deuterated formyl groups can be efficiently and selectively synthesized using D2O as a cost-effective deuterium source without the need for presynthesizing the aldehyde.
Ibrahim, Malek Y. S.,Denmark, Scott E.
p. 10362 - 10367
(2018/07/31)

Palladium-Catalyzed Reductive Conversion of Acyl Fluorides via Ligand-Controlled Decarbonylation
Ligand-controlled non-decarbonylative and decarbonylative conversions of acyl fluorides were developed using a Pd(OAc)2/Et3SiH combination. When tricyclohexylphosphine (PCy3) was used as the ligand, aldehydes were obtained as simple reductive conversion products. The use of 1,2-bis(dicyclohexylphosphino)ethane (Cy2P(CH2)2PCy2, DCPE) as the ligand, however, favored the formation of hydrocarbons, which are decarbonylative reduction products.
Ogiwara, Yohei,Sakurai, Yuka,Hattori, Hiroyuki,Sakai, Norio
supporting information
p. 4204 - 4208
(2018/07/29)

Custom Hydrosilane Synthesis Based on Monosilane
The omnipresence of silicon compounds with carbon substituents in synthetic chemistry hides the fact that, except for certain substitution patterns at the silicon atom, their preparation is often far from trivial. The challenge is rooted in the lack of control over nucleophilic substitution with carbon nucleophiles at silicon atoms with three or four leaving groups. For example, SiCl4 usually converts into intractable mixtures of chlorosilanes, typically requiring several distillation cycles to reach high purity. Accordingly, there is no universal approach to silanes with heteroleptic substitution. Here, using a bench-stable SiH4 surrogate, we introduce a general strategy for the on-demand synthesis of silicon compounds decorated with different aryl and alkyl substituents. Reliable protocols are the basis of the selective and programmable synthesis of dihydro- and monohydrosilanes; aryl-substituted trihydrosilanes are also accessible in a straightforward fashion. These otherwise difficult-to-access hydrosilanes are only three or fewer easy synthetic operations away from the SiH4 surrogate. Synthesizing silicon compounds with different carbon substituents from inorganic silicon precursors, i.e., basic silicon chemicals with hydrogen, halogen, or alkoxy substitution, is an intricate and often insoluble task. It is generally difficult to chemoselectively address one of these groups in chemical reactions, particularly when two or more of those are identical. Complicated separation and purification procedures are the result. The challenge of making these silicon compounds containing silicon–carbon bonds, typically hydro- and chlorosilanes, is accentuated considering their high demand in academia and industry. The present approach is a step forward in solving those limitations. It hinges on the stepwise decoration of the silicon atom of a liquid monosilane surrogate. Further development of this strategy and adjusting it to industrial needs could pave the way to easy access of an even more diverse manifold of silicon compounds for synthetic chemistry and material science. Oestreich and colleagues present an approach to the chemoselective stepwise preparation of hydrosilanes with the general formula R4–nSiHn where n = 1–3 and R can be different aryl and alkyl groups. The starting point is a bench-stable SiH4 surrogate with two Si–H bonds masked as cyclohexa-2,5-dien-1-yl substituents. A sequence of palladium-catalyzed Si–H arylation and B(C6F5)3-promoted deprotection and transfer hydrosilylation enables the programmable synthesis of hydrosilanes, even with three different substituents at the silicon atom.
Yuan, Weiming,Smirnov, Polina,Oestreich, Martin
supporting information
p. 1443 - 1450
(2018/04/20)

Dual Roles for Potassium Hydride in Haloarene Reduction: CSNAr and Single Electron Transfer Reduction via Organic Electron Donors Formed in Benzene
Potassium hydride behaves uniquely and differently than sodium hydride toward aryl halides. Its reactions with a range of haloarenes, including designed 2,6-dialkylhaloarenes, were studied in THF and in benzene. In THF, evidence supports concerted nucleophilic aromatic substitution, CSNAr, and the mechanism originally proposed by Pierre et al. is now validated through DFT studies. In benzene, besides this pathway, strong evidence for single electron transfer chemistry is reported. Experimental observations and DFT studies lead us to propose organic super electron donor generation to initiate BHAS (base-promoted homolytic aromatic substitution) cycles. Organic donor formation originates from deprotonation of benzene by KH; attack on benzene by the resulting phenylpotassium generates phenylcyclohexadienylpotassium that can undergo (i) deprotonation to form an organic super electron donor or (ii) hydride loss to afford biphenyl. Until now, BHAS reactions have been triggered by reaction of a base, MOtBu (M = K, Na), with many different types of organic additive, all containing heteroatoms (N or O or S) that enhance their acidity and place them within range of MOtBu as a base. This paper shows that with the stronger base, KH, even a hydrocarbon (benzene) can be converted into an electron-donating initiator.
Barham, Joshua P.,Dalton, Samuel E.,Allison, Mark,Nocera, Giuseppe,Young, Allan,John, Matthew P.,McGuire, Thomas,Campos, Sebastien,Tuttle, Tell,Murphy, John A.
supporting information
p. 11510 - 11518
(2018/09/12)

Quantitative infrared spectroscopic studies and 2D COS analysis of xylenes isomerization over hierarchical zeolites
The microporous and hierarchical ZSM-5 zeolites were studied with respect to their interaction with o-, m- and p-xylene molecules as well as the catalytic activity in xylenes isomerization process followed by 2D COS analysis of IR spectra. The aspects of mechanism of xylene isomerization reaction have been discussed in the light of the results of 2D COS analysis of IR spectra and catalytic performance of studied zeolites. The ZSM-5 zeolites were characterized by different Si/Al ratio and by various types of generated mesoporosity. This selection assured ability to follow properly the changes in the catalytic performance related not only to acidic properties but also to porosity of the samples. It was shown that the microporous character of zeolites was crucial for high selectivity to the most desired product i.e. p-xylene. In the case of hierarchical zeolites it was confirmed that the formation of by-products as mesitylene and toluene occurred during ortho-xylene isomerization. Furthermore, for hierarchical zeolites the high amount of silanols groups prompted to the coke formation on highly developed external surface.
Tarach, Karolina A.,Go??bek, Kinga,Choi, Minkee,Góra-Marek, Kinga
p. 158 - 171
(2017/01/06)

Standard and rapid scan infrared spectroscopic studies of: O -xylene transformations in terms of pore arrangement of 10-ring zeolites-2D COS analysis
This study attempts to offer an insight into o-xylene isomerization process in terms of steric constraints of 10-ring zeolites. The zeolites under investigation, i.e. ZSM-5, IM-5 and TNU-9, have purely microporous structures and crystals with the same shape and offer comparable protonic functionality, both in manner of amount and strength of Si(OH)Al groups. Under these conditions, micropore topology is recognised to deliver differentiated catalytic performance of each zeolitic structure. Moreover, 10-ring zeolites of reduced dimensionality, i.e. TNU-10 and ZSM-22, are chosen as reference materials. The 2D COS analysis of IR spectra reveal that interaction and catalytic activity in o-xylene isomerization process are strongly influenced by diffusion of reagents in rigid microporous environment and the formation of intermediate species is characterised by IR bands at 1485 and 1455 cm-1. With a prolonged time of the reaction (15 min), the formation of the latter species is observed for zeolite IM-5 characterised by limited 3-dimensionality. Rapid scan experiments show that in a shorter reaction time (4 min), these intermediate moieties are present for all the structure studied. The intermediate species are believed to originate from arenium ions such as methylbenzenium CH3-C6H5+-CH3 and/or methyl-substituted cycloheptatrienyl ions CH3-C7H7+. Their amount is strictly related to the rigidity of the microporous system: the most spacious environment for o-xylene transformation, e.g. TNU-9, is characterised by the lowest population of intermediates, whereas structures offering sufficiently tight geometry, e.g. TNU-10, can accommodate intermediate species in higher quantities, finally leading to the production of p-xylene with high selectivity.
Go?bek, Kinga,Tarach, Karolina A.,Góra-Marek, Kinga
p. 9934 - 9950
(2017/08/10)

Transfer Hydro-dehalogenation of Organic Halides Catalyzed by Ruthenium(II) Complex
A simple and efficient Ru(II)-catalyzed transfer hydro-dehalogenation of organic halides using 2-propanol solvent as the hydride source was reported. This methodology is applicable for hydro-dehalogenation of a variety of aromatic halides and α-haloesters and amides without additional ligand, and quantitative yields were achieved in many cases. The potential synthetic application of this method was demonstrated by efficient gram-scale transformation with catalyst loading as low as 0.5 mol %.
You, Tingjie,Wang, Zhenrong,Chen, Jiajia,Xia, Yuanzhi
p. 1340 - 1346
(2017/02/10)

Method for producing aromatic hydrocarbon by cycloaddition
The invention relates to a method for producing aromatic hydrocarbon by cycloaddition. The method comprises the following step: enabling raw materials to be in contact with a catalyst to produce aromatic hydrocarbon flow containing benzene, methylbenzene or dimethylbenzene. The raw materials comprise diene and dienophile. The diene has a structural formula (I) as shown in the specification, in the formula (I), R1 and R2 are hydrogen, optional substituted C1-20 straight chain or branched chain alkyls, optional substituted C2-20 straight chain or branched chain alkenyls, optional substituted C2-20 straight chain or branched chain alkynyls, optional substituted C3-20 cycloalkyls or optional substituted C6-20 aryls, and the dienophile is C2-C4 alcohol. The method can be used for industrial production of preparation of aromatic hydrocarbons by non-fossil resources.
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Paragraph 0054; 0055

(2017/05/18)

Mechanistic Study of the Role of Substrate Steric Effects and Aniline Inhibition on the Bis(trineopentylphosphine)palladium(0)-Catalyzed Arylation of Aniline Derivatives
The mechanism of the bis(trineopentylphosphine)palladium(0) (Pd(PNp3)2)-catalyzed coupling of aryl halides and aniline derivatives was studied in an effort to understand the role of substrate steric effects on the reaction. Prior studies had shown that the rate of Pd/PNp3-catalyzed coupling of aryl bromides and aniline derivatives was largely unaffected by substrate steric demand. The oxidative addition of aryl bromides to Pd(PNp3)2 is found to follow first-order kinetics with a rate that is independent of both ligand and aryl halide concentration. Thus, the rate limiting step for oxidative addition of aryl bromides is irreversible ligand dissociation. In the case of aryl chlorides, the oxidative addition rate has a first-order dependence on [ArCl] and an inverse dependence on [PNp3], indicating a mechanism involving reversible dissociation of the ligand followed by rate limiting oxidative addition. This difference in aryl halide effect was also found for the catalytic coupling reaction. Aryl bromide steric demand does not affect the coupling rate with hindered anilines, whereas the coupling rate of aryl chlorides is negatively affected by substrate steric demand. These results suggest that oxidative addition is rate limiting in the catalytic reaction for aryl chlorides but that oxidative addition is not rate limiting for aryl bromides. Aniline was found to give coupling rates significantly slower than those of 2,6-diisopropylaniline for both aryl bromides and chlorides. Aniline promotes the decomposition of the [(PNp3)Pd(Ar)(μ-X)]2 catalytic intermediate to a catalytically inactive palladacycle ([(κ2-P,C-Np2PCH2C(Me2)CH2)Pd(μ-X)]2) through C-H activation of a neopentyl group and elimination of arene. These studies show that the ability of the Pd/PNp3 catalyst system to tolerate steric demand in aryl bromides stems from the fact that the rate limiting step of the catalytic cycle is independent of the concentration and steric demand of aryl bromides. A catalyst deactivation pathway involving ligand metalation was identified that is promoted by unhindered aniline derivatives.
Hu, Huaiyuan,Qu, Fengrui,Gerlach, Deidra L.,Shaughnessy, Kevin H.
p. 2516 - 2527
(2017/06/01)

Conversion of propionic acid and 3-pentanone to hydrocarbons on ZSM-5 catalysts: Reaction pathway and active site
Conversion of propionic acid to gasoline-range molecules was investigated at 350?°C on a series of ZSM-5 catalysts with varying density of Br?nsted acid sites (BAS), achieved by ion exchange of proton with Na+. Ketonization of propionic acid to 3-pentanone is the primary reaction, with the sequential aldol condensation to dipentanone alcohol being the secondary. The major reaction pathway for forming the aromatics involves dehydration, cyclization, dehydration and hydride transfer from dipentanone alcohol, leading to the formation of C10 aromatics before being dealkylated to lighter aromatics. Temperature programmed desorption of propionic acid indicates that the reaction initiates with acylium cation formation on BAS through dehydration. Comparing the turnover frequencies of ketonization and aldol condensation on ZSM-5 with varying density of BAS indicates that BAS is the active site for both reactions. The propionic acid feed deactivates the catalyst faster than the 3-pentantone feed due to a stronger adsorption of propionic acid on the acid sites of ZSM-5.
Wang, Xuefen,Ding, Shuang,Wang, Hua,Liu, Xiao,Han, Jinyu,Ge, Qingfeng,Zhu, Xinli
p. 79 - 89
(2017/08/03)

Evidence of single electron transfer from the enolate anion of an: N, N ′-dialkyldiketopiperazine additive in BHAS coupling reactions
A designed N,N′-dialkyldiketopiperazine (DKP) provides evidence for the role of DKP additives as initiators that act by electron transfer in base-induced homolytic aromatic substitution reactions, involving coupling of haloarenes to arenes.
Emery, Katie J.,Tuttle, Tell,Murphy, John A.
p. 8810 - 8819
(2017/11/03)

Insight into forced hydrogen re-arrangement and altered reaction pathways in a protocol for CO2 catalytic processing of oleic acid into C8-C15 alkanes
A new vision of using carbon dioxide (CO2) catalytic processing of oleic acid into C8-C15 alkanes over a nano-nickel/zeolite catalyst is reported in this paper. The inherent and essential reasons which make this achievable are clearly resolved by using totally new catalytic reaction pathways of oleic acid transformation in a CO2 atmosphere. The yield of C8-C15 ingredients reaches 73.10 mol% in a CO2 atmosphere, which is much higher than the 49.67 mol% yield obtained in a hydrogen (H2) atmosphere. In the absence of an external H2 source, products which are similar to aviation fuel are generated where aromatization of propene (C3H6) oxidative dehydrogenation (ODH) involving CO2 and propane (C3H8) and hydrogen transfer reactions are found to account for hydrogen liberation in oleic acid and achieve its re-arrangement in the final alkane products. The reaction pathway in the CO2 atmosphere is significantly different from that in the H2 atmosphere, as shown by the presence of 8-heptadecene, γ-stearolactone, and 3-heptadecene as reaction intermediates, as well as a CO formation pathway. Because of the highly dispersed Ni metal center on the zeolite support, H2 spillover is observed in the H2 atmosphere, which inhibits the production of short-chain alkanes and reveals the inherent disadvantage of using H2. The CO2 processing of oleic acid described in this paper will significantly contribute to future CO2 utilization chemistry and provide an economical and promising approach for the production of sustainable alkane products which are similar to aviation fuel.
Xing, Shiyou,Lv, Pengmei,Yuan, Haoran,Yang, Lingmei,Wang, Zhongming,Yuan, Zhenhong,Chen, Yong
supporting information
p. 4157 - 4168
(2017/09/07)

A green organic boron reagent carbon boron key cracking hydrogenation of the new method (by machine translation)
The invention relates to a kind of green, efficient organic boron reagent carbon boron key cracking hydrogenation of the new method. The method uses a cheap and easily obtained inorganic base as catalyst, common organic alcohol as the reaction solvent and a hydrogen source, is placed under the environment of air can be conveniently catalytic organic boric acid or borate generating carbon boron key cracking hydrogenation reaction, the reaction substrate universality is wide, functional group compatibility outstanding. System realizing metallic catalytic various boric acid and boric acid ester in the fracture of the carbon boron key reaction, also overcome the traditional method requires the use of greatly excessive inorganic alkali, organic acid in great harm to the environment or complex metal catalyst to the limitations of the b-hydrogenation, laboratory preparation and industrial production organoboron reagent of the b-hydrogenation reaction provides a completely new strategy. (by machine translation)
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Paragraph 0022; 0023

(2017/10/09)

Effect of the nature of sulfur compounds on their reactivity in the oxidative desulfurization of hydrocarbon fuels with oxygen over a modified CuZnAlO catalyst
The reactivity of thiophene, dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT), which are the representatives of the main classes of sulfur compounds that are the constituents of diesel fractions, was studied in the course of their oxidative desulfurization with oxygen on a CuO/ZnO/Al2O3 catalyst modified with boron and molybdenum additives. At T ≥ 375°C, the reactivity increased in the order thiophene 2 from hydrocarbon fuel, which was simulated by a solution of 4,6-DMDBT in toluene, was 80%. Under the assumption of a first order reaction with respect to sulfur compound and oxygen, the apparent activation energies of the test processes were calculated. An attempt was made to reveal the role of the adsorption of sulfur compounds in the overall process of oxidative desulfurization with the use of X-ray diffraction analysis, X-ray photoelectron spectroscopy, and differential thermal and thermogravimetric analysis with the massspectrometric monitoring of gas phase composition.
Yashnik,Salnikov,Kerzhentsev,Saraev,Kaichev,Khitsova,Ismagilov,Yamin,Koseoglu
p. 58 - 72
(2017/03/11)

Prefunctionalized Porous Organic Polymers: Effective Supports of Surface Palladium Nanoparticles for the Enhancement of Catalytic Performances in Dehalogenation
Three porous organic polymers (POPs) containing H, COOMe, and COO?groups at 2,6-bis(1,2,3-triazol-4-yl)pyridyl (BTP) units (i.e., POP-1, POP-2, and POP-3, respectively) were prepared for the immobilization of metal nanoparticles (NPs). The ultrafine palladium NPs are uniformly encapsulated in the interior pores of POP-1, whereas uniform- and dual-distributed palladium NPs are located on the external surface of POP-2 and POP-3, respectively. The presence of carboxylate groups not only endows POP-3 an outstanding dispersibility in H2O/EtOH, but also enables the palladium NPs at the surface to show the highest catalytic activity, stability, and recyclability in dehalogenation reactions of chlorobenzene at 25 °C. The palladium NPs on the external surface are effectively stabilized by the functionalized POPs containing BTP units and carboxylate groups, which provides a new insight for highly efficient catalytic systems based on surface metal NPs of porous materials.
Zhong, Hong,Liu, Caiping,Zhou, Hanghui,Wang, Yangxin,Wang, Ruihu
p. 12533 - 12541
(2016/08/24)

Catalytic reactions of dimethyl disulfide with thiophene and benzene
The gas-phase reaction of dimethyl disulfide with thiophene proceeds under the action of acid catalysts under atmospheric pressure at 160-350°C and a residence time of τ = 0.6-21 s to form thioalkylation and alkylation products. Dimethyl disulfide reacts with benzene to form only alkylation products. Catalysts containing both strong protic and Lewis acid sites, as well as basic sites of moderate strength, are the most active ones.
Mashkina,Khairulina
p. 72 - 81
(2016/04/20)

A facile strategy for preparation of phosphorus modified HZSM-5 shape-selective catalysts and its performances in disproportionation of toluene
The phosphorous modified HZSM-5 catalysts were prepared by using phosphoric acid as the precursor with the addition of ethanol during the impregnation process and their shape-selective performances in the synthesis of p-xylene by disproportionation of toluene were investigated. An excellent para-selectivity along with a relatively high catalytic activity was achieved over the phosphorous modified HZSM-5 catalysts. The addition of ethanol during the impregnation process promotes the transition of phosphoric acid to phosphate, which accomplished the cover of the external acid sites and the reserve of the acid sites in the pores of HZSM-5 zeolite after phosphorous modification.
Liu, Na,Zhu, Xingxing,Hua, Songjie,Guo, Dengfeng,Yue, Hongyun,Xue, Bing,Li, Yongxin
p. 60 - 64
(2016/02/09)

PROCESSES FOR CONVERSION OF BIOLOGICALLY DERIVED MEVALONIC ACID
The invention relates to a process comprising reacting mevalonic acid, or a solution comprising mevalonic acid, to yield a first product or first product mixture, optionally in the presence of a solid catalyst and/or at elevated temperature and/or pressure. The invention further relates to a process comprising: (a) providing a microbial organism that expresses a biosynthetic mevalonic acid pathway; (b) growing the microbial organism in fermentation medium comprising suitable carbon substrates, whereby biobased mevalonic acid is produced; and (c) reacting said biobased mevalonic acid to yield a first product or first product mixture.
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Paragraph 0095-0103

(2016/06/13)

Impact of pore topology and crystal thickness of nanosponge zeolites on the hydroconversion of ethylbenzene
The gas-phase hydroconversion of ethylbenzene was investigated in the presence of intimate mixtures of ?MRE, MFI and MTW-type zeolite nanosponges and a hydrogenating component (Pt/Al2O3). The nanomorphic zeolites were prepared using multiammonium surfactants acting as dual-porogenic agents directing the formation of micro- and mesopores simultaneously. The effects of the zeolite topology (pore size and dimensionality) and crystal thickness on the product selectivity of ultra-thin zeolite frameworks (10 nm) were investigated. The enhanced catalytic activity confirmed the importance of improved molecular diffusion. These nanosponges were unique in producing more xylenes, suggesting lower confinement effects. The selectivity for p-xylene and the selectivity towards ethylbenzene hydroisomerization, dealkylation, disproportionation, transalkylation and hydrocracking were evaluated. Despite the similar 10 nm crystal thickness of all the nanosponge zeolites, the presence of spacious channel interconnections in MFI was concluded to remarkably impact the product selectivity compared to straight channels as in ?MRE and MTW. Our findings clarify the relatively unexplored transformation of alkyl-aromatics over ultra-thin zeolite crystals, through five typical catalytic reactions of major industrial interest.
Marques Mota,Eliá?ová,Jung,Ryoo
p. 2653 - 2662
(2016/05/24)

Implementing thermally-excited-catalytic course solely using ambient heat motivation for efficient abatement of water pollutants
Interest in photocatalysis has been fascinated by the realization that solar light is effectively an inexhaustible energy resource. Nevertheless, the necessity for high-energy ultraviolet irradiation and excessive recombination of photogenerated electrons
Luo, Xuegang,Zhang, Sizhao,Ding, Feng,Lin, Xiaoyan
p. 18040 - 18051
(2016/03/01)

A kind of O-cresol and 2,6-xylenol method for the synthesis of
The invention discloses a method for synthesizing 2,6-xylene and o-cresol by means of co-production. The method includes steps loading iron composite oxide catalysts into a fixed-bed reactor; preparing the o-cresol and the 2,6-xylenol by means of reaction under certain conditions. The certain conditions includes that dimethyl ether with the flow rate of 5-50mL/min is used as carrier gas, a molar ratio of phenol to methanol is 1:1-20, the phenol and the methanol are used as raw materials, the temperatures are 300-400 DEG C, and the weight space velocity of the phenol is 0.1-1h. A molar composition ratio Fe:Zr:Ti:Si:Cs of the iron composite oxide catalysts is 1:(0.05-1.0):(0.01-0.1):(0.01-0.1):(0.001-0.01). The method has the advantages that the dimethyl ether is used as the carrier gas, so that decomposition of the methanol can be prohibited in reaction procedures, the methanol utilization rate can be obviously increased, and the service lives of the catalysts can be prolonged.
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Paragraph 0025

(2016/12/22)

KOtBu: A Privileged Reagent for Electron Transfer Reactions?
Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes, and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction.
Barham, Joshua P.,Coulthard, Graeme,Emery, Katie J.,Doni, Eswararao,Cumine, Florimond,Nocera, Giuseppe,John, Matthew P.,Berlouis, Leonard E. A.,McGuire, Thomas,Tuttle, Tell,Murphy, John A.
supporting information
p. 7402 - 7410
(2016/07/06)