- A ZEOLITE CATALYST AND USE THEREOF FOR THE DEHYDROGENATION OF ALKANES
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The present invention relates to a zeolite catalyst, wherein the zeolite catalyst comprises a zeolitic material, wherein the framework of the zeolitic material comprises Y02 and X203, wherein Y is a tetravalent element and X is a trivalent element, wherein the Y : X molar ratio of Y and X contained in the framework of the zeolitic material is comprised in the range of from 500 to 10,000, and wherein the zeolite catalyst further comprises Pt which is supported on the zeolitic material. Furthermore, the present invention relates to a molding comprising the zeolite catalyst, as well as to processes for the preparation of the molding. The present invention also relates to a process for the dehydrogenation of alkanes using the inventive zeolite catalyst or molding, as well as to their respective use. In particular, the catalyst can be Pt/ZSM-5, Pt-Zn/ZSM-5, Pt-K/ZSM-5 or Pt-Zn-K / ZSM-5, with the zeolite exhibiting a Si/A I molar ratio of 850.
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Page/Page column 29-31
(2022/02/05)
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- A pronounce approach on the catalytic performance of mesoporous natural silica toward esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols
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Catalytic esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols in the liquid phase over unmodified natural silica catalyst has been studied. The virgin and calcined catalysts were characterized by thermal analyses (Thermogravimetry (TG) and diffrential thermal analysis (DTA)), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and N2 sorption analyses. The acidity of natural silica catalysts was investigated using isopropyl alcohol dehydration and chemisorption of pyridine and dimethyl pyridine. The results indicated that most of the acidic sites are of Br?nsted type and of intermediate strength. The effect of different parameters such as reaction time, molar ratio, catalyst dosage, and calcination temperature was studied. Natural silica catalyst exhibited excellent catalytic performance with a selectivity of 100% to acetate esters formation. The maximum yields of isoamyl, benzyl, and cinnamyl acetate esters obtained in the batch conditions were 80, 81, and 83%, respectively. Whereas on adopting a simple distillation technique, these yields were successfully improved to higher values of 97, 98, and 90%, respectively. Experimental results manifested that the reaction followed Langmuir–Hinshelwood mechanism. Finally, the catalyst could be completely recycled without loss of its activity after four cycles of the esterification reactions.
- Said, Abd El-Aziz A.,Abd El-Wahab, Mohamed M. M.,El-Gamal, Nadia O.,Goda, Mohamed N.
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p. 257 - 268
(2021/12/14)
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- TfO-···H-O-H Interaction-Assisted Generation of a Silicon Cation from Allylsilanes: Access to Phenylallyl Ferrier Glycosides from Glycals
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We demonstrate here that the strained and bulky protonated 2,4,6-tri-tert-butylpyridine (TTBPy) triflate salt serves as a mild and efficient organocatalyst for the diastereoselective C-Ferrier glycosylation of various glycals. The importance of the role of the 1/2 H2O molecule trapped in the catalyst has been disclosed. The mechanism of action involves unique anionic triflate and H2O hydrogen-bond interactions that assist the activation of allylsilanes, providing unprecedented access to diastereoselective phenylallyl Ferrier glycosides.
- Addanki, Rupa Bai,Halder, Suvendu,Kancharla, Pavan K.
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supporting information
p. 1465 - 1470
(2022/02/23)
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- Investigation on the Thermal Cracking and Interaction of Binary Mixture of N-Decane and Cyclohexane
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Abstract: The investigation about the thermal cracking performance and interaction of different components in hydrocarbon fuels is of great significance for optimizing the formulation of high-performance hydrocarbon fuels. In this work, thermal cracking of n-decane, cyclohexane and their binary mixture were studied in a tubular reactor under different temperatures and pressures. The gas and liquid products were analyzed in detail with different gas chromatography. The main gas products of pure n-decane and cyclohexane are similar, and there is a certain difference in the main liquid products. For binary mixture, the overall conversion rate and gas yield are lower than their theoretical value. The cracking conversion rate of n-decane in binary mixture is lower than that in pure n-decane, but the opposite change occurs for cyclohexane, and the effect become more obvious as the increase of the reaction pressure. These experimental phenomena can be explained by bond dissociation energy and free radical reaction mechanism. The pressure affects the free radical reaction path, and high pressure is more conducive to bimolecular hydrogen abstraction reaction, which will lead to different product content. A law of interaction between the n-decane and cyclohexane was observed according to the experimental results. [Figure not available: see fulltext.]
- Chen, Xuejiao,Pang, Weiqiang,Wang, Bo,Zhang, Ziduan,Zhou, Lingxiao,Zhu, Quan
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-
- Impact of composition and structural parameters on the catalytic activity of MFI type titanosilicalites
-
Titanosilicalite of the MFI type was obtained via a hydrothermal method. Its initial and annealed at 75 °C (TS-1P(75)) and 500 °C (TS-1P(500)) forms were studied by X-ray powder diffraction (PXRD), X-ray absorption spectroscopy (XAS-method), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), temperature-programmed ammonia desorption (TPD NH3), and pyridine adsorption (Py). The full-profile Rietveld method allowed us to observe the presence of the organic template tetrapropylammonium hydroxide (TPAOH) in the framework voids, as well as to determine the silicate module (Si/Ti = 73.5) and the distribution of Ti4+ ions over the MFI-type structure sites (Ti atoms replace Si ones in two positions: T1 and T6). The coordination numbers of titanium (CNTi = 4.6 for TS-1P and TS-1P(75), CNTi = 3.8 for TS-1P(500)) were established by the XAS-method. The catalytic activity of titanosilicalites was found in the reactions of nitrous oxide decomposition (the maximal decomposition rate is demonstrated for the TS-1P(75) sample), allyl chloride epoxidation to epichlorohydrin (the best combination of all indicators was exhibited for the TS-1P sample) and propane conversion (maximum propane conversion, and butadiene and propylene selectivity were observed in both TS-1P(75) and TS-1P(500) samples). Mechanisms for the catalytic processes are proposed. The relationship between the catalytic properties and the composition (Si/Ti), Ti4+ ion distribution over the MFI-type structure sites, the local environment of titanium ions, and the number of acid sites in the titanosilicalites are discussed.
- Bruk, Lev,Chernyshev, Vladimir,Khramov, Evgeny,Kravchenko, Galina,Kustov, Aleksander,Kustov, Leonid,Kuz'Micheva, Galina,Markova, Ekaterina,Pastukhova, Zhanna,Pirutko, Larisa
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p. 3439 - 3451
(2022/03/14)
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- Transformation synthesis of SSZ-13 zeolite from ZSM-35 zeolite
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Interzeolite conversion as a promising alternative strategy for zeolite synthesis has received extensive attention. It is of great significance to understand the potential rules of conversion between zeolites with different topologies for effective regulation of zeolite synthesis. Hydrothermal conversion of ZSM-35 (FER-type) zeolite containing the mor composite building units into SSZ-13 zeolite (CHA-type) using N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH) as template was performed for the first time. The effects of TMAdaOH/SiO2 ratio, Na2O/SiO2 ratio, the additional starting zeolite and crystallization time on the interzeolite conversion of ZSM-35 into SSZ-13 were investigated. The interzeolite conversion mechanism concerning the synthesis of SSZ-13 from ZSM-35 zeolite was proposed and verified by DFT calculation. The results of DFT calculations suggested that ZSM-35 zeolite with mor composite building unit had the potential to decompose into 6-Membered Rings, and further transform into CHA-type zeolite containing d6r composite building unit. Therefore, zeolites containing mor structure have the potential to be converted into zeolites containing d6r structure.
- Bing, Liancheng,Cong, Wenwen,Han, Dezhi,Li, Kexu,Li, Qiang,Wang, Fang,Wang, Guangjian,Xu, Changyou
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- Light Olefin Production Method Comprising Catalyst Regeneration Using Low Temperature Oxidizing Gas
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The present invention relates to a method for producing light olefins, and more particularly, to a method for producing light olefins by alternately supplying reactants and catalyst regeneration by catalytic inactivation by reaction, 1) supplying reactants to a reactor filled with a catalyst to produce a target olefin. 2) The process of 1), wherein the deactivated catalyst is fired in the presence of an oxidizing gas. 3) Step 2), and repeating the step 1). And. In step 2), NO). 2 The method for producing light olefins according to 2), wherein the regeneration temperature of the step is maintained equal to the reaction temperature of the step 1).
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Paragraph 0065-0066; 0068-0069; 0071-0073; 0075-0078; ...")
(2021/07/13)
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- Understanding the origin of selective oxidative dehydrogenation of propane on boron-based catalysts
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Boron-based catalysts have been reported to exhibit high selectivity to olefins in oxidative dehydrogenation of propane (ODHP). However, the origin of their superior ODHP selectivity to conventional vanadium-based catalysts is still under debate. In this work, we proposed that oxidized boron species is the active site for highly selective olefin formation in ODHP on boron-based catalysts. Combined isotopic and kinetic experiments suggested that O2 weakly bonds to the electron-deficient B center to form non-dissociative >B–O-O–BB–O-O–B sites. These findings offer in-depth knowledge of ODHP on boron-based catalysts.
- Li, Jiwei,Lin, Jingdong,Qian, Shuya,Tian, Jinshu,Wan, Shaolong,Wang, Shuai,Wang, Yong,Zhang, Zhaoxia
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- STABLE, HIGH SELECTIVITY CATALYSTS AND CATALYST SYSTEMS, AND PROCESSES FOR THEIR USE
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The present invention relates to catalysts, catalyst systems, and processes for the production of valuable light olefins, such as C2-C4 olefins (ethylene, propylene, and/or butenes) from paraffinic hydrocarbons, such as propane, through dehydrogenation and metathesis. Some particular aspects relate to the discovery of non-precious metal catalysts and catalyst systems utilizing such catalysts, for example in the case of being in an admixture with a metathesis catalyst, which advantageously exhibit high performance in terms of activity, selectivity, and stability. Other advantages can include a reduced production of byproducts (e.g., methane and ethane) that result from undesired side reactions, in addition to benefits that may be attained through the addition of a sulfur-bearing compound (e.g., H2S).
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-
Paragraph 84-87; 92; 93; 96
(2021/08/06)
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- INTEGRATED PROCESS FOR PRODUCING OLEFINS FROM ALKANES BY HYDROGEN TRANSFER
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This application relates to transfer hydrogenation between light alkanes and olefins, and, more particularly, embodiments related to an integrated olefin production system and process which can produce higher carbon number olefins from corresponding alkanes. Examples methods may include reacting at least a portion of the ethylene and the at least one alkane via transfer hydrogenation to produce at least a mixed product stream comprising generated ethane from at least a portion of the ethylene, unreacted ethylene, and an olefin corresponding to the at least one alkane.
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Paragraph 0051
(2021/04/02)
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- MWW TYPE ZEOLITE, METHOD FOR PRODUCING SAME, AND CRACKING CATALYST
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Provided are the following: an MWW type zeolite which has many Br?nsted acid sites when in the form of a proton type and which is highly suitable as a cracking catalyst for cumene; a method for producing same; and an application of same. The present invention provides an MWW type zeolite in which the ratio (B/A) of the peak intensity (B) attributable to tetracoordinate aluminum relative to the peak intensity (A) attributable to hexacoordinate aluminum is 2 or more in 27Al MAS NMR, when measured as an ammonium type. The present invention also provides a method for producing an MWW type zeolite, the method having a step for carrying out a hydrothermal synthesis reaction in the presence of: a seed crystal of an MWW type zeolite containing no organic structure-directing agent; and a reaction mixture containing a silica source, an alumina source, an alkali source, an organic structure-directing agent, and water. The reaction mixture satisfies the following molar ratio: X/SiO20.15 (here, X denotes the number of moles of the organic structure-directing agent).
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Paragraph 0142-0144
(2021/01/21)
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- Selective Preparation of Olefins through Conversion of C2 and C3 Alcohols on NASICON-Type Phosphates
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Abstract—: We have studied the catalytic activity of LiZr2(PO4)3-based NASICON-type phosphates for conversion of C2 and C3 aliphatic alcohols with the aim of selectively preparing C2–C4 olefins. Selectivity has been controlled via partial heterovalent substitutions of In3+ or Nb5+ for Zr4+ or Mo for phosphorus. We have investigated the structure and morphology of the synthesized catalysts. The nature of the dopants has been shown to play a key role in determining the selectivity of the catalysts studied. Partial In3+ substitution for Zr4+ improves the dehydrogenating properties of the materials, whereas partial substitutions of Nb5+ for Zr4+ and Mo6+ for P5+ improve their dehydrating properties. We have demonstrated the possibility of highly selective preparation of ethylene and butylenes from ethanol and of propylene from propanol-1 and propanol-2.
- Ermilova, M. M.,Il’in, A. B.,Orekhova, N. V.,Yaroslavtsev, A. B.
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p. 693 - 700
(2021/07/26)
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- Sulfonated nanoporous activated carbons for catalytic isopropyl alcohol dehydration
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Sulfonation of nanoporous activated carbon (NAC) was performed in the different ways available within the synthetic organic chemistry armory for preparing solid acid catalysts of isopropyl alcohol dehydration (IDH). The sulfonated NACs, with from 0.15 to 1.0 mmol of sulfo groups per gram of NAC, have good catalytic performance. Sulfonated oligo- and poly(α-methylstyrene)s grafted on the oxidized NAC exhibited superior catalytic activity and high stability in the IDH reaction. Conversion of isopropyl alcohol to propene of about 100% was achieved with these catalysts at temperatures in the range of 140–170 °C. Most catalysts obtained are active in the IDH reaction; however, we observed that the propene yield depends on the method used for the NAC sulfonation.
- Grishchenko, Liudmyla M.,Yatsymyrskiy, Andrii V.,Matushko, Igor P.,Klymchuk, Dmytro O.,Mischanchuk, Oleksandr V.,Boldyrieva, Olga Yu.,Diyuk, Vitaliy E.
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- Alcohol-assisted synthesis of high-silica zeolites in the absence of organic structure-directing agents
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In this work, we show for the first time that high-silica zeolites (MFI, TON, MTT, and *MRE) could be synthesized from a combined strategy of both zeolite seeding and alcohol filling in the absence of organic structure-directing agents (OSDAs). High-silica ZSM-5 zeolites with Si/Al ratios ranging from 38 to 240 (TF-Al-ZSM-5) could be synthesized via this route. The key to the success of this technique was the employment of an aluminosilicate precursor with a fully 4-coordinated aluminum species as the initial source, wherein the rearrangement and condensation of the silicate species, rather than the aluminate species, occurred during zeolite crystallization. In addition, heteroatoms, such as Fe and B, could be incorporated into the zeolite frameworks. Catalytic tests for the methanol-to-propylene (MTP) reaction exhibited good catalytic performance for TF-Al-ZSM-5, which was comparable to that of the aluminosilicate ZSM-5 zeolite synthesized with OSDAs. Hence, this method offers viable opportunities for the industrial production and catalytic application of high-silica zeolites in the future.
- Luan, Huimin,Lei, Chi,Ma, Ye,Wu, Qinming,Zhu, Longfeng,Xu, Hao,Han, Shichao,Zhu, Qiuyan,Liu, Xiaolong,Meng, Xiangju,Xiao, Feng-Shou
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p. 563 - 570
(2020/09/01)
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- Bridging the Gap: From Homogeneous to Heterogeneous Parahydrogen-induced Hyperpolarization and Beyond
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Demonstration of parahydrogen-induced polarization effects in hydrogenations catalyzed by heterogeneous catalysts instead of metal complexes in a homogeneous solution has opened an entirely new dimension for parahydrogen-based research, demonstrating its applicability not only for the production of catalyst-free hyperpolarized liquids and gases and long-lived non-equilibrium spin states for potential biomedical applications, but also for addressing challenges of modern fundamental and industrial catalysis including advanced mechanistic studies of catalytic reactions and operando NMR and MRI of reactors. This essay summarizes the progress achieved in this field by highlighting the research contributed to it by our colleague and friend Kirill V. Kovtunov whose scientific career ended unexpectedly and tragically at the age of 37. His role in this research was certainly crucial, further enhanced by a vast network of his contacts and collaborations at the national and international level.
- Chekmenev, Eduard Y.,Goodson, Boyd M.,Bukhtiyarov, Valerii I.,Koptyug, Igor V.
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p. 710 - 715
(2021/04/14)
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- Oxidative Cracking of Propane in the Presence of Hydrogen
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The effect of H2 additions to the initial mixture on the parameters of the oxidative cracking of propane at atmospheric pressure, temperatures of 500°C–750°C, reaction time of 2 s, and С3H8/О2 initial ratio ~2 was experimentally evaluated. Results revealed that small amounts of H2 promoted the process due to the formation of additional active radicals OH? and H?. Performance of the oxidative cracking of propane in a large excess of H2 led to an increase in the yield of methane and ethane, while the yield of ethylene, the target product of the process, decreased.
- Arutyunov, V. S.,Nikitin, A. V.,Ozerskii, A. V.,Sedov, I. V.,Timofeev, K. A.,Zimin, Ya. S.
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p. 787 - 792
(2021/08/13)
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- Insight into Carbocation-Induced Noncovalent Interactions in the Methanol-to-Olefins Reaction over ZSM-5 Zeolite by Solid-State NMR Spectroscopy
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Carbocations such as cyclic carbenium ions are important intermediates in the zeolite-catalyzed methanol-to-olefins (MTO) reaction. The MTO reaction propagates through a complex hydrocarbon pool process. Understanding the carbocation-involved hydrocarbon pool reaction on a molecular level still remains challenging. Here we show that electron-deficient cyclopentenyl cations stabilized in ZSM-5 zeolite are able to capture the alkanes, methanol, and olefins produced during MTO reaction via noncovalent interactions. Intermolecular spatial proximities/interactions are identified by using two-dimensional 13C–13C correlation solid-state NMR spectroscopy. Combined NMR experiments and theoretical analysis suggests that in addition to the dispersion and CH/π interactions, the multiple functional groups in the cyclopentenyl cations produce strong attractive force via cation-induced dipole, cation–dipole and cation–π interactions. These carbocation-induced noncovalent interactions modulate the product selectivity of hydrocarbon pool reaction.
- Cai, Wenjin,Chu, Yueying,Deng, Feng,Hu, Min,Li, Shenhui,Qi, Guodong,Wang, Chao,Wang, Qiang,Xu, Jun
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supporting information
p. 26847 - 26854
(2021/11/17)
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- Synergistic effect of Fe and Ga incorporation into ZSM-5 to increase propylene production in the cracking ofn-hexane utilizing a microchannel reactor
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In the present study, the effect of various amounts of Fe and Ga in the catalytic cracking ofn-hexane in a microchannel reactor was investigated using experimental design by the D-optimal method. Nano zeolites incorporated with Fe and Ga metals were synthesized in a fluorine environment to investigate the synergistic effect of the metals on the textural and acidic properties of the catalysts, which ultimately improved the performance of the synthesized catalysts in the efficient production of light olefins, in particular propylene. Three synthesis parameters including the Si/Al, Si/Fe and Si/Ga ratios were considered as the main factors to determine the optimal conditions for obtaining the maximum conversion ofn-hexane, yield of light olefins, and P/E ratio and minimum yield of alkanes as the responses. In sample FeGa-1, the P/E ratio reached 3.97, indicating the significant effect of the substituted metals in improving the desirable routes for propylene production. According to the results of the acidic properties, Fe, Al and Ga increased the number of total acid sites and the strengths of strong and weak acid sites, respectively. In addition, according to the results obtained from sample FeGa-7, the synergistic effect of Fe and Ga increased the number of weak acid sites.
- Halimitabrizi, Parya,Rashidzadeh, Mehdi,Sakha, Mohsen Rostami,Salari, Darush,Soltanali, Saeed
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p. 13833 - 13846
(2021/08/16)
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- CATALYST AND METHOD FOR PREPARING LIGHT OLEFIN USING DIRECT CONVERSION OF SYNGAS
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A catalyst for preparing light olefin using direct conversion of syngas is a composite catalyst and formed by compounding component I and component II in a mechanical mixing mode. The active ingredient of component I is a metal oxide; and the component II is one or more than one of zeolite of CHA and AEI structures or metal modified CHA and/or AEI zeolite. A weight ratio of the active ingredients in the component Ito the component II is 0.1-20. The reaction process has high product yield and selectivity, wherein the sum of the selectivity of the propylene and butylene reaches 40-75%; and the sum of the selectivity of light olefin comprising ethylene, propylene and butylene can reach 50-90%. Meanwhile, the selectivity of a methane side product is less than 15%.
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Paragraph 0082; 0085
(2021/04/30)
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- Clean protocol for deoxygenation of epoxides to alkenes: Via catalytic hydrogenation using gold
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The epoxidation of olefin as a strategy to protect carbon-carbon double bonds is a well-known procedure in organic synthesis, however the reverse reaction, deprotection/deoxygenation of epoxides is much less developed, despite its potential utility for the synthesis of substituted olefins. Here, we disclose a clean protocol for the selective deprotection of epoxides, by combining commercially available organophosphorus ligands and gold nanoparticles (Au NP). Besides being successfully applied in the deoxygenation of epoxides, the discovered catalytic system also enables the selective reduction N-oxides and sulfoxides using molecular hydrogen as reductant. The Au NP catalyst combined with triethylphosphite P(OEt)3 is remarkably more reactive than solely Au NPs. The method is not only a complementary Au-catalyzed reductive reaction under mild conditions, but also an effective procedure for selective reductions of a wide range of valuable molecules that would be either synthetically inconvenient or even difficult to access by alternative synthetic protocols or by using classical transition metal catalysts. This journal is
- Fiorio, Jhonatan L.,Rossi, Liane M.
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p. 312 - 318
(2021/01/29)
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- Quantification of Redox Sites during Catalytic Propane Oxychlorination by Operando EPR Spectroscopy
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Identification and quantification of redox-active centers at relevant conditions for catalysis is pivotal to understand reaction mechanisms and requires development of advanced operando methods. Herein, we demonstrate operando EPR spectroscopy as an important technique to quantify the oxidation state of representative CrPO4 and EuOCl catalysts during propane oxychlorination, an attractive route for propylene production. In particular, we show that the space-time-yield of C3H6 correlates with the amount of Cr2+ and Eu2+ ions generated over the catalysts during reaction. These results provide a powerful strategy to gather quantitative understanding of selective alkane oxidation, which could potentially be extrapolated to other functionalization approaches and operating conditions.
- Zichittella, Guido,Polyhach, Yevhen,Tschaggelar, René,Jeschke, Gunnar,Pérez-Ramírez, Javier
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p. 3596 - 3602
(2020/12/17)
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- Nb?V Mixed Oxide with a Random Assembly of Pentagonal Units: A Catalyst for Oxidative Dehydrogenation of Ethane and Propane
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High-dimensionally structured (HDS) mixed oxides of vanadium with metals (M) (e. g., Nb, Mo, and W; denoted as HDS-MVO) were constructed by {M6O21}12? pentagonal units and {MO6} (M=Nb, Mo, W, or V) octahedra as linkers. The materials were synthesized using a hydrothermal method and rod-shaped solids. The random assembly of the pentagonal units and octahedra in the cross-sectional plane of the rods facilitated the formation of micropore channels along the long axis of the rods. Micropore formation was directly observed in the cross-section by HAADF-STEM. These structural features are common to HDS-NbVO, HDS-MoVO, and HDS-WVO. The catalytic activity of these three HDS-MVOs with V/Mo ratios in the range 0.35–0.39 was tested for the oxidative dehydrogenation of ethane and propane. The reaction rates per surface area for ethane oxidation and propane oxidation over the HDS-MoVO and HDS-WVO catalysts were comparable, whereas the HDS-NbVO catalyst showed an appreciable difference between the two reaction rates. Both HDS-MoVO and HDS-WVO exhibited higher selectivity for olefin formation during ethane oxidation than propane oxidation. Interestingly, the olefin selectivity over the HDS-NbVO catalyst was found to be almost independent of the alkane substrate. These catalytic features were discussed on the basis of V?O?V or V?O?Mo redox coupling and pore structure effects in HDS-MoVO and HDS-WVO and also of isolated and valence stable surface V in HDS-NbVO.
- Shimoda, Kosuke,Ishikawa, Satoshi,Matsumoto, Katsuya,Miyasawa, Mai,Takebe, Marino,Matsumoto, Riku,Lee, Syutoku,Ueda, Wataru
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p. 3132 - 3139
(2021/05/29)
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- Pd-Modified ZnO-Au Enabling Alkoxy Intermediates Formation and Dehydrogenation for Photocatalytic Conversion of Methane to Ethylene
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Photocatalysis provides an intriguing approach for the conversion of methane to multicarbon (C2+) compounds under mild conditions; however, with methyl radicals as the sole reaction intermediate, the current C2+ products are dominated by ethane, with a negligible selectivity toward ethylene, which, as a key chemical feedstock, possesses higher added value than ethane. Herein, we report a direct photocatalytic methane-to-ethylene conversion pathway involving the formation and dehydrogenation of alkoxy (i.e., methoxy and ethoxy) intermediates over a Pd-modified ZnO-Au hybrid catalyst. On the basis of various in situ characterizations, it is revealed that the Pd-induced dehydrogenation capability of the catalyst holds the key to turning on the pathway. During the reaction, methane molecules are first dissociated into methoxy on the surface of ZnO under the assistance of Pd. Then these methoxy intermediates are further dehydrogenated and coupled with methyl radical into ethoxy, which can be subsequently converted into ethylene through dehydrogenation. As a result, the optimized ZnO-AuPd hybrid with atomically dispersed Pd sites in the Au lattice achieves a methane conversion of 536.0 μmol g-1 with a C2+ compound selectivity of 96.0% (39.7% C2H4 and 54.9% C2H6 in total produced C2+ compounds) after 8 h of light irradiation. This work provides fresh insight into the methane conversion pathway under mild conditions and highlights the significance of dehydrogenation for enhanced photocatalytic activity and unsaturated hydrocarbon product selectivity.
- Jiang, Wenbin,Low, Jingxiang,Mao, Keke,Duan, Delong,Chen, Shuangming,Liu, Wei,Pao, Chih-Wen,Ma, Jun,Sang, Shuaikang,Shu, Chang,Zhan, Xiaoyi,Qi, Zeming,Zhang, Hui,Liu, Zhi,Wu, Xiaojun,Long, Ran,Song, Li,Xiong, Yujie
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supporting information
p. 269 - 278
(2021/01/12)
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- Mo–V–O nanocrystals synthesized in the confined space of a mesoporous carbon
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Ternary Mo–V oxide nanocrystals (Nano-MoVO) were hydrothermally synthesized in the confined space of a mesoporous carbon template and tested in the oxidative dehydrogenation (ODH) of ethane and propane. The synthesized nanocrystals are approximately 60 nm in length, 20 nm in diameter on average, and possess a structure resembling orthorhombic MoVO (Orth-MoVO) as indicated by spectroscopic and microscopy characterization. The Nano-MoVO catalyst has a 5-fold higher mesopore volume and a 4-fold larger external surface area than an Orth-MoVO synthesized by a conventional method (Orth-MoVO) as characterized through N2 adsorption analysis. Nano-MoVO shows similar activation energy in the ODH of ethane compared with other conventional MoVO catalysts. However, Nano-MoVO exhibits significantly higher propane/ethane activation rate ratio and higher propene selectivity even in the absence of elements such as Te and Nb that suppress overoxidation of propane-derived species to COx. The results suggest the benefits of the nanocrystalline morphology to limit overoxidation.
- Mukai, Shin R.,Obunai, Ryo,Ogino, Isao,Tamura, Keisuke,Ueda, Wataru
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- PROCESS FOR CONVERTING ONE OR MORE METHYL HALIDES INTO ETHYLENE AND PROPYLENE
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The present disclosure concerns a process for converting methyl halides to ethylene and propylene, said process comprising the steps of (a) providing a feedstream comprising methyl halides; (b) providing a first and second catalyst composition, said second catalyst composition comprising a cracking catalyst; (c) contacting said feedstream with said first catalyst composition in a first reaction zone under first reaction conditions to provide a first product stream; and (d) subjecting at least a part of said first product stream to an Olefin Catalytic Cracking with said second catalyst composition in a second reaction zone under second reaction conditions to provide a second product steam. The process is remarkable in that said step (c) is performed under 400°C, and in that said first catalyst composition comprises molecular sieves with a Si/Al atomic between 2 and 18 and with a plurality of pores with a shape of an 8-membered ring or less.
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Page/Page column 29
(2021/05/29)
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- PROCESS FOR CONVERTING ONE OR MORE METHYL HALIDES INTO C3-C5 ALPHA OLEFINS
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The present disclosure relates to a process for converting methyl halides to C3-C5 α-olefins, said process comprising the steps of (a) providing a feedstream comprising methyl halides; (b) providing a first and second catalyst composition, said second catalyst composition comprising a metathesis catalyst; (c) contacting said feedstream with said first catalyst composition in a first reaction zone under first reaction conditions to provide a first product stream, and (d) contacting said first product stream with an olefin stream and with said second catalyst composition in a second reaction zone under second reaction conditions to provide a second product steam. The process is remarkable in that said step (c) is performed under 400°C, and in that said first catalyst composition comprises molecular sieves with a Si/Al atomic ratio between 2 and 18 and with a plurality of pores with a shape of an 8-membered ring or less.
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Page/Page column 27-29
(2021/05/29)
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- Rational construction of hierarchical SAPO-34 with enhanced MTO performance without an additional meso/macropore template
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A relatively facile strategy was rationally developed for the synthesis of hierarchical SAPO-34 using aluminum phosphate spheres as the nutrient and mesoporogen, without utilizing any additional meso/macropore-directing agents. The simple synthesis resulted in SAPO-34 (CHA) with classical rhombohedral morphology with dimensions between 2 and 3 μm and intracrystalline meso/macropores. It was demonstrated that the employment of spherical aluminum phosphate particles and the regulation of synthesis conditions to carry out the dissolution of aluminum phosphate spheres parallel to the crystallization process of the CHA phase were crucial factors leading to successful synthesis. The crystallization process of the hierarchical SAPO-34 was investigated and a possible crystallization model was proposed. The catalytic performances of the synthesized SAPO-34s in the MTO reaction were evaluated. The SAPO-34 with a hierarchical porous structure exhibited an improved catalytic lifespan and higher selectivity for light olefins. This work not only provides a new facile method to synthesize hierarchical SAPO-34 but also holds great promise for offering useful guidance for the synthesis of other aluminophosphate zeolites with hierarchical structures.
- Liang, Yafei,Gao, Beibei,Zhou, Lipeng,Yang, Xiaomei,Lu, Tianliang,Yao, Hongchang,Su, Yunlai
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p. 1859 - 1867
(2021/02/03)
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- CATALYST COMPOSITIONS AND METHODS OF PREPARATION AND USE THEREOF
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Disclosed are catalyst compositions containing a hydrogen/copper-chabazite (H/Cu- CHA) zeolite with silica (SiO2) and alumina (AI2O3) at a silica-alumina ratio (SAR) of about 5:1 to about 50:1 and about 0.1 wt% to about 5.0 wt% of a copper oxide. Also disclosed are methods of preparation and methods of use thereof.
- -
-
Paragraph 0006-0010; 0017-0018; 0056-0059; 0069-0070
(2021/03/05)
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- Investigation of the Effect of Crystallization Temperature and Time in Synthesis of SAPO-34 Catalyst for the Production of Light Olefins
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Abstract: In this paper, the effect of variation of crystallization temperatures and times on the synthesis of SAPO-34 catalysts for conversion of methanol to light olefins has been investigated. These are two of the very effective parameters in the synthesis of SAPO-34 which affect phase purity, crystallinity, acidic properties, and finally the performance of catalysts. For this purpose, 9 samples have been synthesized by varying of temperature and time of crystallization in the range of 170–210°C, 12–36 h, respectively and the molar ratio of 1Al2O3 : 1P2O5 : 0.4 SiO2: 0.5 TEAOH : 1.5 MOR : 70 H2O and characterized by XRD, SEM, FTIR, BET, and NH3–TPD techniques. Finally, performance of catalysts was investigated in the process of conversion of methanol to light olefins in a fixed-bed reactor 410°C. The results show that crystallinity, phase purity, size, and distribution of particles, surface area, and acidic properties have great effects on performance and selectivity of ethylene and propylene and these properties themselves severely depend on Crystallization temperature and time. The results of characterized of catalysts show that high characterized temperature, reduces the phase purity and increases size in particles. The catalysts that have been synthesized at 190°C and 24 h have the highest crystallinity, suitable size, and distribution of particles, high surface area, and suitable acidic sites, so it has the highest selectivity of light olefins at MTO process.
- Kianfar
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p. 527 - 537
(2021/04/09)
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- High-efficient hierarchical [B]-ZSM-5 catalyst by simultaneously using of CTAB surfactant and boron promoter for methanol to olefins reaction
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In this work, a one-pot hydrothermal route was applied to prepare the hierarchical high-silica ZSM-5 catalyst (Si/Al = 200), including boron promoter in the structure and CTAB surfactant. XRD, FE-SEM, BET, NH3-TPD, and FT-IR techniques were applied to evaluate the physical and chemical properties. The effect of different amounts of secondary template (CTAB) and different operating conditions was studied on the ZSM-5 catalyst preparation and performance in methanol to olefins reaction. The results showed the high surface area (391.8?m2g?1), mesoporous structure, high crystallinity, and well-adjusted acidity for the modified catalyst. The prepared catalyst with CTAB/TPABr molar ratio of 1 led to the highest propylene selectivity (48.56%), the highest P/E ratio of 6.3, and the highest light olefin selectivity (71%). This improved performance can be assigned to the high surface area, short diffusion path length by mesopore structure, and optimum acidity. It was found that the optimum temperature and weight hourly space velocity were 480?°C and 7.2?h?1, respectively.
- Dalirian, Fereshte,Rostamizadeh, Mohammad,Alizadeh, Reza
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p. 3201 - 3215
(2021/04/26)
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- The hydrothermal synthesis of hierarchical SAPO-34 with improved MTO performance
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The fabrication of intracrystalline secondary pores is an important approach to improve the catalytic performance of microporous zeolites. Herein, a two-step crystallization process using only TEAOH/TEA has been developed for the hydrothermal synthesis of hierarchical SAPO-34. When crystalline AlPO4characterized with four-coordinated aluminum and phosphorus atoms was applied, hierarchical SAPO-34 could hydrothermally be synthesized under thenH2O?:?nAl2O3> 20 condition, and the crystallization process was analyzed. The crystalline AlPO4is beneficial for the SAPO-34 synthesis, and hierarchical SAPO-34 with abundant intracrystalline secondary porosity can be efficiently synthesized in 2 h. Although both the distribution range and volume of the mesopores decrease with time, the mesopore volume of hierarchical SAPO-34-31 achieved 0.069 cm3g?1. Furthermore, the silicon atoms in hierarchical SAPO-34-31 are mainly in the Si(OAl)4and Si(OSi)(OAl)3states, and the accessibility would be improved by the intracrystalline mesopores (16-20.3 nm). SAPO-34-31 exhibited more excellent MTO activity than the nano-sized SAPO-34, and the selectivity of ethylene and propylene achieved more than 80%, while thenC2H4?:?nC3H6is always about 0.8.
- Rui, Peixin,Wang, Baorong,Chen, Feibiao,Xiang, Yanjuan,Yang, Jianming,Guo, Tao,Wu, Zheng,Liao, Weilin,Shu, Xingtian
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p. 11093 - 11100
(2021/07/06)
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- Embryonic zeolite-assisted synthesis of SSZ-13 with superior efficiency and their excellent catalytic performance
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An X-ray amorphous material with a CHA-like structure, named embryonic CHA zeolite, has been designed and employed for the synthesis of SSZ-13, which leads to ultra-fast crystallization (1.5-12 h), wide product SiO2/Al2O3ratio (SAR = 22-100) and high yield (82.8-92.9%). The usage ofN,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH) for the synthesis can be controlled at unprecedentedly low amounts (TMAdaOH/SiO2= 0.035-0.050). Characterization results reveal that the embryonic zeolite has a small particle size of 10-20 nm, large micro/mesopore volume and abundant double 6-ring units (subunits of the CHA structure). It provides ample active surface and subunits for the formation of the CHA structure and promotes the fast synthesis of SSZ-13 with a wide phase region. The resultant material (SAR = 23.2), after Cu2+exchange, exhibits superior NH3-SCR activity and extraordinary hydrothermal stability (steaming at 800 °C for 16 h), implying its promising application for NOxremoval. In addition, high-silica SSZ-13 shows good catalytic performance for the MTO reaction. It is anticipated that the embryonic zeolite-assisted strategy will benefit the synthesis of more industrially important zeolites.
- Cui, Wenhao,Fan, Dong,Han, Jingfeng,Li, Bing,Liu, Zhongmin,Tian, Peng,Wang, Juan,Wang, Linying,Zhu, Dali
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p. 15238 - 15245
(2021/07/21)
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- Generating Assembled MFI Nanocrystals with Reduced b-Axis through Structure-Directing Agent Exchange Induced Recrystallization
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Controlling crystal size and shape of zeolitic materials is an effective way to promote their mass transport and catalytic properties. Herein, we report a single step, Na+- and porogen- free crystallization of MFI hierarchical architecture made up of aligned nanocrystals with reduced b-axis thickness (5–23 nm) and adjustable Si/Al ratios between 35 to 120, employing the commonly used tetrapropylammonium hydroxide (TPAOH) and tetrabutylammonium hydroxide (TBAOH) as structure-directing agents (SDAs). Homogeneous nucleation driven by both SDAs and subsequent SDA-exchange induced dissolution-recrystallization are responsible for the formation of such structure. The enhanced textural and diffusion properties account for a notable exaggeration of propene selectivity and catalyst lifetime in dimethyl ether-to-olefins (DTO) conversion. This protocol is extendable to the rational synthesis of other hierarchical zeolites through crystallization process control.
- Zhao, Xiaoling,Zeng, Shu,Zhang, Xueliang,Deng, Quanzheng,Li, Xiujie,Yu, Wenguang,Zhu, Kake,Xu, Shutao,Liu, Jichang,Han, Lu
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supporting information
p. 13959 - 13968
(2021/05/19)
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- CATALYST, AND METHOD FOR DIRECT CONVERSION OF SYNGAS TO PREPARE LIGHT OLEFINS
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A process for direct synthesis of light olefins uses syngas as the feed raw material. This catalytic conversion process is conducted in a fixed bed or a moving bed using a composite catalyst containing components A and B (A+B). The active ingredient of catalyst A is metal oxide; and catalyst B is an oxide supported zeolite. A carrier is one or more of Al2O3, SiO2, TiO2, ZrO2, CeO2, MgO and Ga2O3 having hierarchical pores; the zeolite is one or more of CHA and AEI structures. The loading of the zeolite is 4%-45% wt. A weight ratio of the active ingredients in the catalyst A and the catalyst B is within a range of 0.1-20, and preferably 0.3-5. The total selectivity of the light olefins comprising ethylene, propylene and butylene can reach 50-90%, while the selectivity of a methane byproduct is less than 15%.
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-
Paragraph 0064-0067
(2021/01/26)
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- METHOD FOR PREPARING LIGHT OLEFIN THROUGH CATALYTIC SYNGAS WITH HIGH SELECTIVITY BY HETEROATOM-DOPED ZEOLITE
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A composite catalyst containing heteroatom-doped zeolite for preparing light olefin using direct conversion of syngas formed by compounding component I and component II in a mechanical mixing mode. The active ingredient of component I is a metal oxide, and the component II is a heteroatom-doped zeolite. The zeolite topology is CHA or AEI, and the skeleton atoms include Al—P—O or Si—Al—P—O; the heteroatoms is at least one of divalent metal Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Mo, Cd, Ba and Ce, trivalent metal Ti and Ga, and tetravalent metal Ge. A weight ratio of the active ingredient in the component I to the component II is 0.1-20. The reaction process has high light olefin selectivity; the sum selectivity of the light olefin including ethylene, propylene and butylene can reach 50-90%, while the selectivity of a methane side product is less than 7%.
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Paragraph 0077-0079
(2021/11/13)
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- Zeolitic catalytic conversion of alcohols to olefins
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A catalyst composition for converting an alcohol to olefins, the catalyst composition comprising the following components: (a) beta zeolite; (b) at least one element selected from the group consisting of zinc, magnesium, calcium, strontium, sodium, and potassium; and (c) at least one element selected from the group consisting of hafnium, yttrium, zirconium, tantalum, niobium, and tin; wherein the components (b) and (c) are independently within or on a surface of said beta zeolite. The catalyst may also further include component (d), which is copper or silver. Also described herein is a method for converting an alcohol to one or more olefinic compounds, the method comprising contacting the alcohol with a catalyst at a temperature of at least 100° C. and up to 500° C. to result in the alcohol being converted to the one or more olefinic compounds.
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Page/Page column 10; 11
(2021/07/08)
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- Dehydrogenation of Propane in the Presence of CO2 on Supported Monometallic MOy/SiO2 and CrOxMOy/SiO2 (M = Fe, Co, and Ni) Bimetallic Catalysts
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Abstract: An analysis is performed of the physicochemical properties of M/SiO2 (M = Fe, Co, and Ni) oxide monometallic and CrM/SiO2 (M = Fe, Co, and Ni) bimetallic catalysts supported on amorphous silica. The catalysts are characterized via TGA, XRD, UV–Vis diffuse reflectance spectroscopy, and SEM. Adding 1?wt?% of a second transition metal (Fe, Ni, and Co) to the 3% CrOx/SiO2 chromium oxide catalyst substantially raises the conversion of propane to 64% with a drop in the selectivity towards propylene and formation of methane as a main by-product in the case of nickel. Introducing iron and cobalt raises the selectivity towards propylene to 72% with a drop in the conversion of propane.
- Tedeeva,Kustov,Pribytkov,Strekalova,Kalmykov,Dunaev,Kustov
-
-
- Enabling Semihydrogenation of Alkynes to Alkenes by Using a Calcium Palladium Complex Hydride
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Selective hydrogenation of alkynes to alkenes requires a catalytic site with suitable electronic properties for modulating the adsorption and conversion of alkyne, alkene as well as dihydrogen. Here, we report a complex palladium hydride, CaPdH2, featured by electron-rich [PdH2]δ- sites that are surrounded by Ca cations that interacts with C2H2 and C2H4 via σ-bonding to Pd and unusual cation-πinteraction with Ca, resulting in a much weaker chemisorption than those of Pd metal catalysts. Concomitantly, the dissociation of H2 and hydrogenation of C2Hx (x = 2-4) species experience significant energy barriers over CaPdH2, which is fundamentally different from those reported Pd-based catalysts. Such a unique catalytic environment enables CaPdH2, the very first complex transition-metal hydride catalyst, to afford a high alkene selectivity for the semihydrogenation of alkynes.
- Chen, Ping,Chen, Ruting,Gao, Wenbo,Guo, Jianping,Guo, Qing,Pei, Qijun,Qin, Chao,Wu, Anan,Xiong, Zhitao,Yan, Hanxue
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supporting information
p. 20891 - 20897
(2021/12/14)
-
- An Aluminosilicate Zeolite Containing Rings of Tetrahedral Atoms with All Odd Numbers from Five to Eleven
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Herein we report the synthesis, structure solution, and catalytic properties of PST-31, which has an unprecedented framework topology. This high-silica (Si/Al=16) zeolite was synthesized using a pyrazolium-based dication with a tetramethylene linker as an organic structure-directing agent (OSDA) in hydroxide media. The PST-31 structure is built from new building layers containing four-, five-, six-, and seven-membered rings, which are connected by single four-membered rings in the interlayer region to form a two-dimensional pore system. Its channels consist of [4.56.6.9.11] and [5.6.7.9.10.11] cavities and are thus delimited by nine-, ten-, and eleven-membered rings. The OSDA cations in as-synthesized PST-31 were determined to reside without disorder in the large [42.514.64.72.94] cavities composed of smaller [4.56.6.9.11] and [5.6.7.9.10.11] ones, leading to a symmetry coincidence between the OSDA and the surrounding zeolite cavity. The proton form of PST-31 was found to be selective for the cracking of n-hexane to light olefins.
- Jo, Donghui,Zhang, Yaping,Lee, Jeong Hwan,Mayoral, Alvaro,Shin, Jiho,Kang, Na Young,Park, Yong-Ki,Hong, Suk Bong
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supporting information
p. 5936 - 5940
(2021/01/29)
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- CATALYTIC FUNNELING OF PHENOLICS
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In general, present invention concerns an integrated wood-to-xylochemicals biorefinery, enabling production of renewable phenol, phenolic oligomers, propylene, and carbohydrate pulp from lignocellulosic biomass.
- -
-
Paragraph 0034; 0089-0090; 0168
(2021/04/30)
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- Chemoenzymatic Buta-1,3-diene Synthesis from Syngas Using Biological Decarboxylative Claisen Condensation and Zeolite-Based Dehydration
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A method for producing buta-1,3-diene (1,3-BD) by an amalgamation of chemical and biological approaches with syngas as the carbon source is proposed. Syngas is converted to the central intermediate, acetyl-CoA, by microorganisms through a tetrahydrofolate metabolism pathway. Acetyl-CoA is subsequently converted to malonyl-CoA using a carbonyl donor in the presence of a carboxylase enzyme. A decarboxylative Claisen condensation of malonyl-CoA and acetaldehyde ensues in the presence of acyltransferases to form 3-hydroxybutyryl-CoA, which is subsequently reduced by aldehyde reductase to give butane-1,3-diol (1,3-BDO). An ensuing dehydration step converts 1,3-BDO to 1,3-BD in the presence of a chemical dehydrating reagent.
- Balasubramaniam, Sivaraman,Badle, Sneh,Badgujar, Swati,Veetil, Vinod P.,Rangaswamy, Vidhya
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p. 705 - 711
(2020/12/01)
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- Iron and copper nanoparticles inside and outside carbon nanotubes: Nanoconfinement, migration, interaction and catalytic performance in Fischer-Tropsch synthesis
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Carbon materials have attracted increasing attention as supports for metal catalysts. Iron-containing carbon nanotubes often promoted with copper have found application in Fischer-Tropsch synthesis, which provides an alternative way for conversion of renewable feedstocks to chemicals and fuels. In carbon nanotubes, the active phase can be nanoconfined inside the channels or localized on the outer surface. In most of previous work, the distribution of metal nanoparticles inside or outside carbon nanotubes is considered to be immobile during the catalyst activation or catalytic reaction. In this paper, we uncovered remarkable mobility of both iron and copper species in the bimetallic catalysts between inner carbon nanotube channels and outer surface, which occurs in carbon monoxide and syngas, while almost no migration of iron species proceeds in the monometallic catalysts. This mobility is enhanced by noticeable fragility and defects in carbon nanotubes, which appear on their impregnation with the acid solutions of metal precursors and precursor decomposition. Remarkable mobility of iron and copper species in bimetallic catalysts affects the genesis of iron active sites, and enhances interaction of iron with the promoter. In the bimetallic iron-copper catalysts, the major increase in the activity was attributed to a higher reaction turnover frequency over iron surface sites located in a close proximity with copper.
- ?míd, B?etislav,Addad, Ahmed,Fellenberg, Ana Katiuce,Hong, Jingping,Ji, Gang,Khodakov, Andrei Y.,Kosto, Yuliia,Simon, Pardis
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p. 306 - 323
(2021/10/29)
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- Rapid hydrothermal synthesis of hierarchical ZSM-5/beta composite zeolites
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An innovative hydrothermal method has been successfully applied to the synthesis of hierarchical ZSM-5/beta composite zeolites with different mass ratios. Firstly, the ZSM-5 zeolites were coated with amorphous silica and aluminum species by a spray drying process. Then, the precursor powder was hydrothermally crystallized for only 1-2 days with the addition of tetraethyl ammonium hydroxide (TEAOH). The obtained products were characterized by XRD, SEM, TEM, N2physical adsorption-desorption,27Al MAS NMR, ICP, pyridine-IR and NH3-TPD techniques. The characterization results imply that the ZSM-5/beta composite zeolites exhibit hierarchical-pores, higher external surface areas and larger mesopore volumes as compared to those of the pure ZSM-5 and beta zeolite. Moreover, the pore structure and acid sites of the ZSM-5/beta composite can be adjusted by changing the mass ratio of ZSM-5/beta. Finally, the ZSM-5/beta composite catalysts exhibit good catalytic performances in the cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB).
- Liu, Jiaxu,Liu, Liping,Meng, Feifei,Xiong, Guang,Zhao, Leping
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p. 21235 - 21247
(2021/07/01)
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- Investigating hydrogenation and decarbonylation in vapor-phase furfural hydrotreating over Ni/SiO2 catalysts: Propylene production
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Furfural can be mass-produced from lignocellulose biomass and can be a platform chemical for producing valuable chemicals. In this study, we examine Ni/SiO2 catalysts for the conversion of furfural under a hydrogen atmosphere. The reactivity an
- Chen, Szu-Hua,Tseng, Ya-Chun,Yang, Sheng-Chiang,Lin, Shawn D.
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- Coupling conversion of methane with carbon monoxideviacarbonylation over Zn/HZSM-5 catalysts
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Efficient direct transformation of methane into value-added chemicals has great significance for long-term sustainability of fuels and chemicals, but remains a major challenge due to its high inertness. Reported here is that methane can be activated effectivelyviacarbonylation with CO over Zn/HZSM-5 catalysts under mild conditions. The selectivity to aromatics alone reaches 80% among all hydrocarbon products at 823 K, whereas as high as 92% ethane selectivity is achieved at a lower temperature of 673 K.13CO isotope labelling experiments demonstrate that approximately 50% of the carbon atoms in all the products originate from carbon monoxide, whereas another half of the carbons come from methane, indicating that the precursors of hydrocarbon products are acyl compounds and/or acetic acid formed by carbonylation of methane with carbon monoxide. This provides potential for transformation of methane into value-added chemicals under mild reaction conditions.
- Wen, Fuli,Zhang, Jin,Chen, Zhiyang,Zhou, Ziqiao,Liu, Hongchao,Zhu, Wenliang,Liu, Zhongmin
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p. 1358 - 1364
(2021/03/14)
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- RED SLUDGE USED AS A CATALYST FOR OLEFIN ISOMERIZATION
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The invention relates to systems and a method for isomerizing a charge to form a stream of alpha-olefin product. An example of a process includes calcination of red mud, flow of an olefin feedstock onto red sludge in an isomerization reactor, and separation of alpha-olefin from reactor effluent.
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Paragraph 0034
(2021/12/31)
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- The Hydrodeoxygenation of Glycerol over NiMoSx: Catalyst Stability and Activity at Hydropyrolysis Conditions
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Catalytic activity tests were run to elucidate the chemistry and catalyst stability for the hydrodeoxygenation of glycerol and other aliphatic oxygenates over a NiMoSx/Al2O3 catalyst at different pretreatments at hydropyrolysis conditions in a continuous flow reactor. Reactivity metrics were developed to quantify and compare the reactivity of NiMo for deoxygenation, hydrogenation, and C?C cleavage. Activity experiments showed sulfided NiMo and reduced NiMo catalysts had similar deoxygenation and hydrogenation activity for glycerol HDO at 400 °C and 270 psig H2 with the NiMoSx catalyst showing higher C?C cleavage activity. Without a sulfur co-feed, both the NiMoSx and NiMoOx catalysts lost >40 % deoxygenation activity over 30 h time on stream. With a 2100 ppm H2S co-feed the NiMoSx catalyst showed a 12 times decrease in the deactivation rate for deoxygenation and 6 time decrease in the deactivation rate for hydrogenation. The main products at high conversion were propylene, propane, ethylene, methane, CO, methanol, ethanol, and 1-propanol. At low conversion, the major products were unsaturated allyl alcohol, acrolein, hydroxyacetone, and acetaldehyde. With no H2S co-feed at short contact times, there was a significant amount of carbon loss possibly due to condensation reactions, while at 2100 ppm H2S in the feed, the carbon balance was 102.4 %. Temperature programmed oxidation of the spent NiMoSx catalysts after 30 h of glycerol HDO without an H2S co-feed showed that one of the causes of deactivation was coking.
- Anderson, Anthony D.,Lanci, Michael P.,Buchanan, J. Scott,Dumesic, James A.,Huber, George W.
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p. 425 - 437
(2020/11/30)
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- Faujasite silicalites for oxidative dehydrogenation of n-octane: Influence of alkali metals, gallium, and boron on catalyst activity
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The sol-gel method was used to synthesize faujasite type silicalites bearing gallium and boron in the framework. Barium and sodium were used as charge balancing cations since isomorphic substitution of Si4+ by Ga3+ or B3+ results in a negative excess charge of the framework. The successful synthesis of this type of silicalites (GaBaY-S, BBaY-S, GaBBaY-S(IE), GaNaY-S) was confirmed using powder-XRD. SEM analysis showed that the morphology of the catalysts with respect to particle size depended on the framework metals and the charge balancing cation used. Framework Ga containing catalysts showed smaller particle size compared to B containing catalysts. Sodium also yielded a smaller particle-sized catalyst compared to barium. The catalysts were tested in the continuous flow oxidative dehydrogenation (ODH) of n-octane, and the catalytic results showed dependence on the active metal reducibility and acid-base character of the catalysts. At iso-conversion of 8 ± 1 %, the least acidic BBaY-S gave the highest selectivity to octenes (40 %) and the lowest selectivity to COx (28 %), and the most acidic GaNaY-S showed the opposite results with octenes at 17 % and COx at 56 %. The catalysts (BaBY-S and GaBBaY-S(IE) with least total acidity had the greatest quantity of strong acid sites which were attributed to Lewis acid sites, confirmed by the pyridine IR analysis. The GaNaY-S, with the highest total acidity, had the least strong acid sites.
- Ndlela, Siyabonga S.,Friedrich, Holger B.,Cele, Mduduzi N.
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- Heterogeneous 1H and 13C Parahydrogen-Induced Polarization of Acetate and Pyruvate Esters
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Magnetic resonance imaging of [1-13C]hyperpolarized carboxylates (most notably, [1-13C]pyruvate) allows one to visualize abnormal metabolism in tumors and other pathologies. Herein, we investigate the efficiency of 1H and 13C hyperpolarization of acetate and pyruvate esters with ethyl, propyl and allyl alcoholic moieties using heterogeneous hydrogenation of corresponding vinyl, allyl and propargyl precursors in isotopically unlabeled and 1-13C-enriched forms with parahydrogen over Rh/TiO2 catalysts in methanol-d4 and in D2O. The maximum obtained 1H polarization was 0.6±0.2 % (for propyl acetate in CD3OD), while the highest 13C polarization was 0.10±0.03 % (for ethyl acetate in CD3OD). Hyperpolarization of acetate esters surpassed that of pyruvates, while esters with a triple carbon-carbon bond in unsaturated alcoholic moiety were less efficient as parahydrogen-induced polarization precursors than esters with a double bond. Among the compounds studied, the maximum 1H and 13C NMR signal intensities were observed for propyl acetate. Ethyl acetate yielded slightly less intense NMR signals which were dramatically greater than those of other esters under study.
- Salnikov, Oleg G.,Chukanov, Nikita V.,Kovtunova, Larisa M.,Bukhtiyarov, Valerii I.,Kovtunov, Kirill V.,Shchepin, Roman V.,Koptyug, Igor V.,Chekmenev, Eduard Y.
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p. 1389 - 1396
(2021/05/31)
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- ALKYL HALIDES CONVERSION INTO C3-C5 ALPHA OLEFINS
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The present disclosure relates to a process for converting alkyl halides to C3-C5 α-olefins, said process comprising the steps of (a) providing a feedstream comprising alkyl halides; (b) providing a first and second catalyst composition, said second catalyst composition comprising a metathesis catalyst; (c) contacting said feedstream with said first catalyst composition in a first reaction zone under first reaction conditions to provide a first product stream, and (d) contacting said first product stream with an olefin stream and with said second catalyst composition in a second reaction zone under second reaction conditions to provide a second product steam. The process is remarkable in that said it comprises a step of steaming said first catalyst composition before the step (c) and in that said first catalyst composition comprises zeolites and a binder, wherein said zeolites comprise at least one 10-membered ring channel.
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Page/Page column 34-37
(2021/05/29)
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