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Cas Database

74-84-0

74-84-0

Identification

  • Product Name:Ethane

  • CAS Number: 74-84-0

  • EINECS:200-814-8

  • Molecular Weight:30.0696

  • Molecular Formula: C2H6

  • HS Code:2901100000

  • Mol File:74-84-0.mol

Synonyms:Bimethyl;Dimethyl;Ethyl hydride;Methylmethane;R 170;R 170 (hydrocarbon);

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Safety information and MSDS view more

  • Pictogram(s):HighlyF+,FlammableF

  • Hazard Codes:F+,F

  • Signal Word:Danger

  • Hazard Statement:H220 Extremely flammable gas

  • First-aid measures: General adviceConsult a physician. Show this safety data sheet to the doctor in attendance.If inhaled Fresh air, rest. Artificial respiration may be needed. Refer for medical attention. In case of skin contact ON FROSTBITE: rinse with plenty of water, do NOT remove clothes. Refer for medical attention . In case of eye contact First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention. If swallowed Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a physician. In high vapor concentrations, can act as simple asphyxiant. Liquid causes severe frostbite. (USCG, 1999)Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]: Vapors may cause dizziness or asphyxiation without warning. Some may be irritating if inhaled at high concentrations. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating and/or toxic gases. (ERG, 2016) FIRST AID: Skin--ON CONTACT WITH LIQUID FROSTBITE: rinse with plenty of water, do NOT remove clothes. Refer for medical attention; Eyes--ON CONTACT WITH LIQUID FROSTBITE. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

  • Fire-fighting measures: Suitable extinguishing media Wear self contained breathing apparatus for fire fighting if necessary. Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]: EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966) and Methane (UN1971) are lighter than air and will rise. Hydrogen and Deuterium fires are difficult to detect since they burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket. (ERG, 2016)Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]: EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966) and Methane (UN1971) are lighter than air and will rise. Hydrogen and Deuterium fires are difficult to detect since they burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket. (ERG, 2016) Wear self-contained breathing apparatus for firefighting if necessary.

  • Accidental release measures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. For personal protection see section 8. Evacuate danger area! Consult an expert! Personal protection: self-contained breathing apparatus. Ventilation. Remove all ignition sources. NEVER direct water jet on liquid. Evacuate danger area! Consult an expert! Personal protection: self-contained breathing apparatus. Ventilation. Remove all ignition sources. NEVER direct water jet on liquid.

  • Handling and storage: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Avoid exposure - obtain special instructions before use.Provide appropriate exhaust ventilation at places where dust is formed. For precautions see section 2.2. Fireproof. Cool. Separated from strong oxidants and halogens.Keep container tightly closed in a dry and well-ventilated place.

  • Exposure controls/personal protection:Occupational Exposure limit valuesBiological limit values Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday. Eye/face protection Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU). Skin protection Wear impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace. Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique(without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands. The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it. Respiratory protection Wear dust mask when handling large quantities. Thermal hazards

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Relevant articles and documentsAll total 1707 Articles be found

Catalytic hydrosilylation of oxalic acid: Chemoselective formation of functionalized C2-products

Feghali, Elias,Jacquet, Olivier,Thuery, Pierre,Cantat, Thibault

, p. 2230 - 2234 (2014)

Oxalic acid is an attractive entry to functionalized C2-products because it can be formed by C-C coupling of two CO2 molecules under electrocatalytic reduction. Herein, we describe the first attempts to reduce oxalic acid by catalytic hydrosilylation. Using B(C6F 5)3 as a Lewis acidic catalyst, oxalic acid can be converted to reduced C2-molecules, with high chemoselectivity, under mild reaction conditions.

Oxidative Condensation of Methane on Sr2 –xLaxTiO4 Catalysts: Effect of the Degree of Substitution of Sr and La

Petrov,Ivanova, Yu. A.,Reshetnikov,Isupova

, p. 862 - 867 (2019)

Abstract: The Sr2 –xLaxTiO4 (x = 0–2.0) catalysts were synthesized based on strontium titanate with a layered perovskite structure. The effect of the degree of substitution of La for Sr on the physicochemical (phase composition and textural characteristics) and catalytic properties of oxides in the oxidative condensation of methane at temperatures of 700–800°C were studied. It was found that multiphase Sr2?–?xLaxTiO4 samples with the degree of substitution x = 0.8–1.8 were most active and selective in the test reaction; this was likely related to the presence of lanthanum oxide and strontium oxide impurities in them, their optimum distribution over the surface, and the specific surface area.

New mechanism of photodissociation of gaseous acetone

Skorobogatov,Meilakhs,Pogosyan,Khripun

, p. 1271 - 1275 (2002)

It is found for the first time that photolysis of gaseous acetone under UV irradiation produces ethane not only via recombination of methyl radicals, but also by the mechanism of induced predissociation.

Mechanisms of 1,1-Reductive Elimination from Palladium: Elimination of Ethane from Dimethylpalladium(II) and Trimethylpalladium(IV)

Moravskiy, A.,Stille, J. K.

, p. 4182 - 4186 (1981)

The energies and entropies of activation for the 1,1-reductive elimination of ethane from cis-bis(diphenylmethylphosphine)dimethylpalladium(II) (2a) in polar and nonpolar solvents were determined.The rates of elimination are slower in polar solvents such as Me2SO, acetone, and acetonitrile than in nonpolar solvents such as benzene.The energies of activation in nonpolar solvents are very close (25 kcal/mol) to the calculated values (extended HMO).Lower energies of activation (6-10 kcal/mol) but high negative entropies of activation (ca.45 eu) in polar solvents are consistent with an elimination that produced a coordinatively unsaturated palladium(0) complex and a late transition state having the characteristics of the product, such that solvent coordinates during the transition state.Reaction of 2a or the corresponding bis(triphenylphosphine)dimetnylpalladium(II) complex 2b with methyl iodide yields ethane and the trans-bis(phosphine)iodomethylpalladium(II) complexes (10a,b).The second-order reaction proceeds through a rate-determining oxidative addition of methyl iodide to 2a,b, yielding the bis(phosphine)iodotrimethylpalladium(IV) intermediate, followed by a rapid elimination.In polar solvents, the rates of these reactions are faster than the 1,1-reductive eliminations from 2a,b mostly because of the lower entropies of activation in the oxidative addition step.In nonpolar solvents, the rates are comparable.The reaction of 2a,b with CD3I gave both C2H6 and C2H3D3, the ratios of these isomers in the reaction of 2a being most consistent with the trans oxidative addition reaction followed by statistical reductive elimination from adjacent methyls.

Gold-doping of carbon-supported palladium improves reduction catalysis

Fang, Yu-Lun,Heck, Kimberly N.,Zhao, Zhun,Pretzer, Lori A.,Guo, Neng,Wu, Tianpin,Miller, Jeffrey T.,Wong, Michael S.

, p. 1776 - 1786 (2016)

Bimetallic palladium-gold (PdAu) catalysts have better catalytic performance than monometallic catalysts for many applications. PdAu catalysts with controlled nanostructures and enhanced activities have been extensively studied but their syntheses require multiple and occasionally complicated steps. In this work, we demonstrated that supported PdAu catalysts could be simply prepared by doping a supported Pd catalyst with gold through wet impregnation and calcination. Resulting PdAu-on-carbon (PdAu/C) catalysts were tested for the room-temperature, aqueous-phase hydrodechlorination of trichloroethene. The most active PdAu/C catalyst (Pd 1.0 wt%, Au 1.1 wt%, dried/air/H2 process) had an initial turnover frequency (TOF) of 34.0 × 10?2 molTCE molPd?1 s?1, which was >15 times higher than monometallic Pd/C (Pd 1.0 wt%, initial TOF of 2.2 × 10?2 molTCE molPd?1 s?1). Through X-ray absorption spectroscopy, the gold kept Pd from oxidizing under calcination at 400 °C. Probable nanostructure evolution pathways are proposed to explain the observed catalysis.

Arrhenius Parameter Determination for the Reaction of Methyl Radicals with Iodine Species in Aqueous Solution

Mezyk, Stephen P.,Madden, Keith P.

, p. 9360 - 9364 (1996)

The techniques of electron pulse radiolysis and direct ESR detection have been used to determine Arrhenius parameters for the recombination reaction of methyl radicals and methyl radical reaction with iodine in aqueous solution.At 22.8 deg C, rate constants of 2k7=(1.77+/-0.16)E9 dm3 mol-1 s-1 and k1=(2.75+/-0.43)E9 dm3 mol-1 s-1, with corresponding activation energies of 14.89+/-0.87 and 13.10+/-0.71 kJ mol-1 (5.7-39.6 deg C), were obtained respectively for these two reactions.The analogous reaction of methyl radicals with iodide or iodate was found to be much slower, with the room temperature rate constant for both reactions estimated as k3 mol-1 s-1.

Kinetic limit of the ethane and ethylene yield in the gas phase condensation of methane

Vedeneev, V. I.,Arutyunov, V. S.,Basevich, V. Ya.

, p. 372 - 373 (1995)

A kinetic simulation of the initiated condensation of methane in the gas phase showed that the additional generation of methyl radicals via the reaction CH4 + I2 -> CH3 + HO2 causes a nearly tenfold increase in the C2 hydrocarbon yield.However, a kinetic limit of the yield exist that is close to that determined in experiments on the catalytic oxidative condensation of methane. - Key words: kinetic simulation; oxidative condensation of methane.

Variability of particle configurations achievable by 2-nozzle flame syntheses of the Au-Pd-TiO2 system and their catalytic behaviors in the selective hydrogenation of acetylene

Pongthawornsakun, Boontida,Mekasuwandumrong, Okorn,Santos Aires, Francisco J.Cadete,Büchel, Robert,Baiker, Alfons,Pratsinis, Sotiris E.,Panpranot, Joongjai

, p. 1 - 7 (2018)

Catalysts with Au and Pd supported on TiO2 (Au:Pd 1:1 wt/wt%) were prepared by 1- and 2-nozzle flame spray pyrolysis (FSP). The 2-nozzle configuration allowed to synthesize various particle configurations by separate or co-feeding of the metal precursor solutions to the two nozzles. For the Au-Pd/TiO2 system, four different catalyst particle configurations were investigated: “TiO2 + AuPd”, “Pd/TiO2 +Au”, “Au/TiO2 +Pd”, and “Pd/TiO2 + Au/TiO2”, where + separates the corresponding precursor solutions fed to the two nozzles. There were no significant differences in the specific surface areas and the average TiO2 crystallite sizes of the catalysts (100 m2/g and 16–17 nm, respectively) with the exception of “Pd/TiO2 +Au/TiO2”, which exhibited larger surface area and smaller crystallite size (152 m2/g, 12 nm) due to halving of the Ti precursor concentration in each nozzle. As revealed by CO chemisorption, XPS, and STEM-EDX results, the catalyst properties varied largely in terms of bimetallic AuPd particle compositions, the interaction between metal–metal and metal-support, and the location of Pd (or AuPd) on the TiO2. Among the catalysts studied, “TiO2 + AuPd” prepared with the 2-nozzle system exhibited the highest conversion of acetylene (~50%) at 40 °C with high selectivity to ethylene ( > 95%). Co-feeding the noble metal precursors together with the Ti precursor afforded less active catalysts due to the formation of Ti-O species partially covering the most active bimetallic AuPd particles. Compared to the commercially available acetylene hydrogenation catalyst and the AuPd/TiO2 prepared by conventional co-impregnation and deposition-precipitation, all the FSP-AuPd/TiO2 catalysts showed superior performances under the reaction conditions used.

Back,Winkler

, p. 718,719 (1954)

Oxidative Coupling of Methane over Na2WO4/CeO2 and Related Catalysts

Yu, Zhenqiang,Yang, Xueming,Lunsford, Jack H.,Rosynek, Michael P.

, p. 163 - 173 (1995)

Na2WO4/CeO2 is an active and selective catalyst for the oxidative coupling of methane (OCM).At 780 deg C and using a reactant feed of CH4:O2:He=4.8:1.0:5.6, a C2 selectivity in excess of 70percent can be achieved over a 9.4 molpercent Na2WO4/CeO2 catalyst at a CH4 conversion of 22percent.By contrast, the C2 selectivity exhibited by pure CeO2 under the same reaction conditions, in the absence of Na2WO4 promoter, is 2- on the calcined catalysts and reveal no evidence for additional surface oxygen species, such as O22- or O-, that might serve as sites for CH4 activation.Pulse reaction experiments show that bulk lattice oxygen species do not participate directly in the OCM reaction, and that the active oxygen species involved in the activation of methane exist only in the presence of gas phase oxygen.Ion scattering spectroscopy and in situ Raman spectroscopy indicate that the initial CeO2 surface of the calcined catalyst is completely covered by one or more layers of Na2WO4, which exists in the molten state under reaction conditions.

Novel catalysts for carbon dioxide-induced selective conversion of methane to C2 hydrocarbons

Cai, Yingchun,Chou, Lingjun,Li, Shuben,Zhang, Bing,Zhao, Jun

, p. 828 - 829 (2002)

The combination of Mn with BaCO3 leads to active catalysts for carbon dioxide-induced selective conversion of methane to ethane and ethylene in the absence of oxygen.

Gas-Phase Proton Affinities for H2O, C2H4 and C2H6

Bohme, Diethard K.,Mackay, Gervase I.

, p. 2173 - 2175 (1981)

Rate and equilibrium constant measurements are reported which provide proton affinities for H2O, C2H4, and C2H6 and heats of formation for the corresponding protonated species at 298 K, on the basis of the well-established proton affinity of CO.The values recommended for the proton affinities are 165.3 +/- 1.8, 163.0 +/- 1.7, and 142.1 +/-1.2 kcal mol-1 for H2O, C2H4, and C2H6, respectively.The proton affinity obtained for H2O is lower than accepted values.The results obtained for C2H4 agree almost exactly with those obtained in a very recent photoionization (PIPECO) study by Baer.The measurements with C2H6 provide a new accurate determination of its proton affinity.

The Role of Coke in Acetylene Hydrogenation on Pd/α-Al2O3

Larsson, Mikael,Jansson, Jonas,Asplund, Staffan

, p. 49 - 57 (1998)

The formation of coke and the influence of the coke on selectivity were investigated during hydrogenation of acetylene on supported palladium catalysts. It was found that the total amount of coke was not directly related to the increase in formation of undesired ethane. Instead, the surface coverage of hydrogen during the deactivation was found to be a crucial parameter. A catalyst deactivated at low hydrogen surface coverage showed a higher ethane selectivity than a sample deactivated at higher surface coverage of hydrogen when compared under the same reaction conditions. In contrast, the coke formation rate was found to increase with increased hydrogen surface coverage. The role of carbon monoxide was also investigated, and the impact on selectivity and coke formation was explained by the reduced surface coverage of hydrogen in the presence of carbon monoxide. The coke was characterized by temperature-programmed oxidation, and deconvolution of the obtained peaks was carried out using a power-law model.

Mechanistic Aspects of Oxidative Coupling of Methane over LaAlO3

Tagawa, Tomohiko,Imai, Hisao

, p. 923 - 930 (1988)

Mechanistic aspects of the oxidative coupling reaction of methane over an LaAlO3 catalyst (La:Al=1:1) prepared by the mist decomposotion method have been studied, using both contonuous-flow and pulsed-flow techniques.The delayed pulse technique together with temperature-programmed desorption reveal that an adsorbed oxygen species is effective in the formation of the C2 compounds, while a gaseous or weakly adsorbed oxygen species is involved in the combustion reaction.Methane cannot stay on the surface stably.Comparing these results with those obtained using the continuous flow reactor, mechanistic aspects are considered from the viewpoint of oxygen activity.The stability of this catalyst is also discussed.

Tailoring the physical and catalytic properties of lanthanum oxycarbonate nanoparticles

Estruch Bosch,Copley,Eralp,Bilbé,Thybaut,Marin,Collier

, p. 104 - 112 (2017)

The synthesis of lanthanum oxide and its carbonate analogues has been performed by flame spray pyrolysis (FSP). Two different feeds have been studied: an organic solution and an aqueous/organic microemulsion. A key experimental parameter of FSP, the O2 dispersion, i.e., the flow rate of the dispersing gas in the FSP nozzle, exhibits an effect on the properties of the materials prepared. Increasing the level of O2 dispersion led to an increase in surface area and a decrease in mean particle size and basicity when a lanthanum containing organic solution was used as FSP feed. Lanthanum can form different phases, such as oxides, hydroxides, oxycarbonates and carbonates. The increase of O2 dispersion also produced a phase change, going from a mixture of type Ia and type II La2O2CO3 and La2O3 to pure La2O3. The use of an aqueous/organic microemulsion feed, which had a higher viscosity than the organic feed, resulted in materials with a lower surface area and a higher mean particle size than those prepared using the organic solution at the same O2 dispersion. In this case a mixture of type II La2O2CO3 and La2O3 was obtained. The materials were tested for oxidative coupling of methane (OCM). We were able to demonstrate that the OCM performance of the materials could be modified by changing the synthesis parameters. For example, lower O2 dispersion produced the highest CH4 and O2 conversions. We also demonstrated that on ageing the mean particle size remain stable; however, the phases do not, showing a new phase, La(OH)3, formation and resulting in an increase in OCM activity. While the OCM performances are modest they do demonstrate the power of this approach for controlled synthesis of lanthanum materials.

The effect of pressure on the surface structure of MgO/BaCO3 catalyst for oxidative coupling of methane

Liu, Yu,Yu, Changchun,Liu, Xuxia,Zhang, Bing,Shen, Shikong

, p. 1127 - 1128 (1996)

The effect of pressure on oxidative coupling of methane (OCM) over MgO/BaCO3 catalyst was studied at the range of 0.1~1.1MPa at 1053 K. Deactivation of the MgO/BaCO3 catalyst at elevated pressure was attributed to the migration of BaCO3 from bulk to the surface of the catalyst.

Oxidative Coupling of Methane over SrCO3 and SrO

Aika, Ken-ichi,Aono, Kenji

, p. 1273 - 1277 (1991)

The oxidative coupling of methane has been studied with an SrCO3-SrO mixed catalyst.Two surface states (an SrO-rich surface and an SrCO3-rich surface) were prepared and examined by various methods including XPS.SrO-rich surfaces, prepared by H2 treatment of SrCO3, had a high C2 yield, and evolved CO2 was absorbed by the catalyst at 1023 K.The bulk diffusion of CO2 was considered to be rapid enough to absorb most of the evolved CO2 and to keep SrO partly on the surface (SrCO3-rich surface) at 1023 K.SrCO3-rich surfaces gave low C2 yields, and the surface was composed of both oxides and carbonates.The active sites were considered to be oxides.The SrO surface was more active than MgO in this reaction.However, it was less active under the steady state because of carbonate formation.

Oxidative coupling of methane in the redox cyclic mode over the Ag-La2O3/SiO2 catalytic system

Greish, Alexander A.,Glukhov, Lev M.,Finashina, Elena D.,Kustov, Leonid M.,Sung, Jae-Suk,Choo, Ko-Yeon,Kim, Tae-Hwan

, p. 92 - 94 (2010)

Synergism of Ag and La2O3 in the Ag-La2O3/SiO2 catalytic system provides substantial efficiency in oxidative coupling of methane carried out in the redox cyclic mode. Selectivity to C2 products can be raised by preliminary injection of small amount of hydrogen to the catalyst.

Electrocatalytic Dehalogenation of 1,2-DihaIoethanes by the C60, C70, C76, C78, and C84 Fullerene Anions: Structure-Reactivity Aspects

D'Souza, Francis,Choi, Jai-Pil,Kutner, Wlodzimierz

, p. 2892 - 2896 (1999)

The homogeneous electrocatalytic reduction of 1,2-dihaloethanes by anions of larger fullerenes, C76, C78, and C84, is presented, and structure-reactivity correlations are derived by including our data reported earlier for the C60 and C70 electrocatalytic process. Cyclic voltammetry measurements indicate that dianions of C76 and C78, as well as trianions of C76, C78, and C84, electrochemically generated in 0.1 M (TBA)PF6, in benzonitrile, catalyze dehalogenation of 1,2-dihaloethanes. Values of the second-order rate constant, k, for the electrocatalytic dehalogenation of 1,2-dihaloethanes by the fullerene anions were determined by using the rotating-disk electrode voltammetry under pseudo-first-order conditions with respect to the 1,2-dihaloethanes. For each fullerene anion, k increases in the order: Cl 84 78 76 70 60, as a function of respective redox potentials of the fullerene, for each 1,2-dihaloethane. Unlike the C60n- electrocatalysis, reported by us earlier to be accompanied by chemical reaction between C60n- and certain ?±,??-diiodoalkanes yielding alkyl adducts of C60, no reaction between the anions of larger fullerenes and 1,2-dihaloethanes was observed within the voltammetric time scale. Because of the high stability with respect to adduct formation and more positive potentials of the electrocatalyses, the larger fullerenes may be more useful than C60 as catalysts, even though the corresponding catalytic rate constants are smaller.

Fine structural photoluminescence spectra of silica-supported zirconium oxide and its photoactivity in direct methane conversion

Yoshida, Hisao,Chaskar, Manohar G.,Kato, Yuko,Hattori, Tadashi

, p. 2014 - 2015 (2002)

Highly dispersed zirconium oxide species on silica exhibit fine structure in phosphorescence emission spectra showing the vibration energy of the photoactive Zr-O-Si linkage to be 955 cm-1, and the species promotes the photoinduced non-oxidativ

Rochow,Dennis

, p. 486 (1935)

A structurally rigid bis(amido) ligand framework in low-coordinate Ni(I), Ni(II), and Ni(III) analogues provides access to a Ni(III) methyl complex via oxidative addition

Lipschutz, Michael I.,Yang, Xinzheng,Chatterjee, Ruchira,Tilley, T. Don

, p. 15298 - 15301 (2013)

A structurally persistent bis-amido ligand framework capable of supporting nickel compounds in three different oxidation states has been identified. A highly unusual, isolable Ni(III) alkyl species has been prepared and characterized via a rare example of a two-electron oxidative addition of MeI to Ni(I).

MANGANESE CATALYSTS FOR THE OXIDATIVE CONDENSATION OF METHANE WITH ALKALI AND ALKALINE-EARTH METAL SALT ADDITIVES

Minachev, Kh. M.,Usachev, N. Ya.,Khodakov, Yu. S.,Udut, V. N.,Makarov, P. A.

, p. 1975 - 1977 (1987)

-

Intrinsic Reactivity of Magnesium Surfaces toward Methyl Bromide

Nuzzo, Ralph G.,Dubois, Lawrence H.

, p. 2881 - 2886 (1986)

The chemisorption and subsequent decomposition of methyl bromide on a Mg(0001) single-crystal surface is found to lead cleanly to the formation of a surface bromide and gas-phase hydrocarbon products including ethane.Stable surface alkyls are not observed even at temperatures as low as -150 deg C.Co-adsorbed dimethyl ether does not perturb this reactivity pattern.The formation of either a thin surface bromide or a surface oxide passivates this material to further reaction under UHV conditions.The implications of these results with respect to the mechanisms of carbon-halogen bond cleavage on magnesium and the formation of Grignard reagents are discussed.

-

Ackermann

, (1937)

-

High-Performance Catalysts Derived from Cupric Subcarbonate for Selective Hydrogenation of Acetylene in an Ethylene Stream

Lu, Chenyang,Zeng, Aonan,Wang, Yao,Wang, Anjie

, p. 997 - 1004 (2021)

A high-performance base metal catalyst for acetylene selective hydrogenation was prepared from cupric subcarbonate (Cu2(OH)2CO3) by thermal treatment with an acetylene-containing gas followed by hydrogen reduction. The characterization results revealed that the copper catalyst was composed of interstitial copper carbide (CuxC) and metal Cu, which were embedded in porous carbon matrix. The CuxC crystallites, which showed outstanding hydrogenation activity, were derived from the hydrogen reduction of copper (II) acetylide (CuC2) which was generated from the reaction between acetylene and Cu2(OH)2CO3. The Cu particles and porous carbon were generated from the unavoidable thermal decomposition of CuC2. The prepared Cu-derived catalyst completely removed the acetylene impurity in an ethylene stream with a very low over-hydrogenation selectivity at 110 °C and atmospheric pressure. No obvious deactivation was observed in a 180-h test run. In the Cu-derived catalyst, CuxC served as the catalytic site for H2 dissociation, Cu mainly functioned as the site for selective hydrogenation of acetylene, whereas the porous carbon matrix posed a steric hindrance effect on the chain growth of linear hydrocarbons so as to suppress the undesired oligomerization.

Peroxide Anions as Possible Active Species in Oxidative Coupling of Methane

Otsuka, Kiyoshi,Jinno, Kiyotaka,Komatsu, Takayuki

, p. 77 - 80 (1987)

Oxidative coupling of CH4 forming C2H6 and C2H4 proceeded smoothly upon contact with Na2O2, BaO2, and SrO2 at low temperature below 673 K.This indicates that O22- ions are very reactive for activation of CH4.O2- ions contained in the peroxides did not activate CH4.

Photooxidation of Ethyl Iodide at 22 deg C

Shepson, Paul B.,Heicklen, Julian

, p. 2691 - 2694 (1981)

C2H5I was photolized at 313 nm and 22 deg C in the presence of either I2, (C2H5)2NOH, or O2-He mixtures.We have determined that the quantum yields for the primary processes C2H5I + hυ -> C2H5 + I (3a) and C2H5I + hυ -> C2H4 + HI (3b) are Φ3a = 0.31 +/- 0.01 and Φ3b = 0.0095 +/- 0.0005.An upper limit for the rate coefficient for the following reaction has been found to be 1 x 1E-14 cm3/(molecule s) at 22 deg C: C2H5 + O2 -> C2H4 + HO2 (1).

A kinetics study for the oxidative coupling of methane on a Mn/Na 2WO4/SiO2 catalyst

Tiemersma,Tuinier,Gallucci,Kuipers,Annaland, M. Van Sint

, p. 96 - 108 (2012)

This paper presents an experimental kinetic study for the oxidative coupling of methane (OCM) over a Mn/Na2WO4/SiO2 catalyst prepared by incipient wetness impregnation. Because the catalyst is a reducible metal oxide, the stability of the catalyst has been assessed by Thermo Gravimetric Analysis (TGA). These experiments show that the catalyst has to be pre-treated with oxygen in order to obtain high C2 selectivity (around 85%) and that a low oxygen partial pressure during the OCM reactions is already sufficient to maintain the catalyst stable in the oxidized state. The catalyst has subsequently been tested in a micro-catalytic fixed bed reactor. The overall reaction orders and rate constants of the primary reactions were determined by measuring the intrinsic reaction rates at different methane and oxygen inlet concentrations. It was found that the reaction order in oxygen for the coupling reaction is 0.38, while the reaction order in oxygen for ethylene oxidation approaches unity, indicating that low oxygen concentration levels are beneficial for obtaining a high C2 selectivity (up to 80-90%). Such a low oxygen concentration can be obtained with distributive feeding in a membrane reactor. Based on the experiments and least-squares minimization, a simplified reaction mechanism is proposed, where the dependency of the ethane (coupling) and carbon dioxide (oxidation) production rates and the secondary ethylene production and C2 oxidation rates can be described with power-law type reaction rate expressions.

Transformation of chlorinated organic compounds by iron and manganese powders in buffered water and in landfill leachate

Schreier, Cindy G.,Reinhard, Martin

, p. 1743 - 1753 (1994)

Tetrachloroethylene was transformed by iron powder (4.1 g/L) in oxygen-free, HEPES-buffered (pH 7) water at 50°C with a half-life of 20 days. The only products observed were the reactive intermediate, trichloroethylene, and ethene and ethane. 1,1,1-Trichloroethane, 1,1-dichloroethylene, and tetrachloroethylene were transformed by iron at room temperature in both autoclaved buffered water and in two non-autoclaved landfill leachates. The pattern and degree of removal were similar in all cases. Dichloromethane, 1,1-dichloroethane, and 1,4-dichlorobenzene were also tested, but were not removed from any of the systems. If manganese rather than iron was used, the substrates transformed depended upon the aqueous phase. Some biological transformations were seen in Leachate 2, but the activity was reduced by manganese and completely suppressed by iron.

Group 5A Metal Oxides as Promoters for Oxidative Coupling of Methane

Yamamura, Masami,Okado, Hideo,Tsuzuki, Naohide

, p. 203 - 206 (1992)

Group 5A metal oxides were tested as promoters for oxidative coupling of methane.They were effective promoters for the coupling reaction, when mixed with 1A, 1A/2A, and 1A/3A oxide catalysts, respectively.Addition of Group 5A metal increased the activity

BaCO3-supported vanadium oxide catalysts for the oxidative coupling of methane

Dang, Zhongyuan,Gu, Jingfang,Lin, Jingzhi,Yang, Dexing

, p. 1901 - 1902 (1996)

BaCO3-supported vanadium oxide catalysts, which consist of BaCO3 and small amounts of a barium orthovanadate Ba3(VO4)2 phase, exhibit high catalytic activity for oxidative coupling of methane, with particularly high activity for ethene and ethane production.

Reactions of C2H5 radicals with HBr and Br at 298 K and millitorr pressures

Dobis, Otto,Benson, Sidney W.

, p. 8171 - 8179 (1995)

The rates of the reactions of ethyl radicals with HBr (k7) and with Br atoms (k8) have been measured at 298 K and millitorr pressures using the Very Low Pressure Reactor (VLPR) technique. The rate constants at 298 K are the following: k7 = (6.67 ± 0.14) × 10-13 cm3/(molecule's) and k8 = (1.19 ± 0.04) × 10-11 cm3/(molecule's). Reaction 7 is a factor of about 14 times slower than had been reported in the only other two direct measurements made (Nicovich, J. M. et al. J. Phys.Chem. 1991, 95, 9890. Seakins, P. W. et al. J. Phys Chem. 1992, 98, 9847) which also reported a negative activation energy for k7 of from -0.8 to -1.1 kcal/mol. Using broadly accepted thermochemistry for reaction 7 and reported values for the reverse reaction, it is shown that all reported data give a positive activation energy for k7.

Silicon-Carbon Bond Formation Kinetics: Study of the Reactions of CH3 with SiH3, Si(CH3)3, and SiCl3

Niiranen, Jukka T.,Gutman, David

, p. 9392 - 9396 (1993)

The kinetics of three Si-C bond-forming association reactions were investigated at the high-pressure limit: SiH3 + CH3 (1), Si(CH3)3 + CH3 (2), and SiCl3 + CH3 (3).Rate constants were measured using a heatable tubular reactor coupled to a photoionization mass spectrometer.The two radical reactants were produced simultaneously (CH3 always in great excess) using pulsed 193-nm photolysis of suitable precursors diluted in helium, and the radical decays were monitored in time-resolved experiments.The radical decay profiles were fitted to appropriate expressions to obtain the desired rate constants.Reaction 1 was studied between 301 and 526 K yielding the following Arrhenius expression for the association reaction: k1 = (5.6 +/- 2.4) * 10-11 exp((3.0 +/- 1.6) kJ mol-1 / RT). (All rate constants are in the units cm3 molecule-1 s-1.) Reaction 2 was investigated between 306 and 526 K yielding the expression k2 = (5.2 +/- 2.2) * 10-11 exp((2.4 +/- 1.4) kJ mol-1 / RT).Reaction 3 was studied at one temperature, 303 K, where k3 = (1.1 +/- 0.4) * 10-10.Treating these association reactions as cross-combination reactions, the measured rate constants were found to be predicted with reasonable accuracy using the geometric mean rule and the rate constants of the related self-association reactions of the reactant radicals.The mechanisms of these reactions are discussed.

Selective Synthesis of Ethylene by Dehydrogenative Coupling of Methane by Use of Thermal Diffusion Column

Yamaguchi, Tatsuaki,Saito, Chiaki

, p. 2649 - 2650 (1988)

Ethylene was found to be obtained dehydrogenatively from methane in extremely high selectivities (91.5percent at 9.4percent conversion of methane) with the downward introduction to the modified thermal diffusion column with electrically heated tungsten wire at 1200 deg C.

Coordination chemistry of the tetrakis(2-hydroxyphenyl)ethene support mimic - Polymetallic magnesium, aluminum, and titanium derivatives

Verkerk, Udo H.,McDonald, Robert,Stryker, Jeffrey M.

, p. 922 - 928 (2005)

The crystal structures of magnesium, aluminum, and titanium coordination complexes of the structurally preorganized tetrakis(2-hydroxyphenyl)ethene are reported. As a result of the absence of steric shielding and the conformational flexibility of the ligand, pseudo-dimeric complexes are formed instead of crown- or raft-like compounds. The unsubstituted tetrakis(2-hydroxyphenyl)ethene ligand thus emulates the complexation characteristics of the sterically open calix[4]arene system.

The study of supported manganese catalysts in the course of the oxidative coupling of methane

Kulichkov,Semikin,Kuzichkin,Lisitsyn

, p. 458 - 461 (2013)

The effect of the process parameters on the yield of the main products, ethane and ethylene, was studied for the methane oxidative dimerization over manganese catalysts deposited on solid carrying agents. The effect of various factors defining activity of manganese systems on their properties was analyzed. The best carrying agent for the catalytic system under study was chosen, and the optimal contents of an active component and a promoting additive providing a high yield of C2 hydrocarbons were determined.

Dzugan, Sharlene T.,Goedken, Virgil L.

, p. 169 - 176 (1988)

Surface processes in the catalytic oxidative coupling of methane to ethane

Buyevskaya, Olga,Wolf, Dorit,Baerns, Manfred

, p. 459 - 464 (1994)

Recent results on surface reaction steps in the oxidative coupling of methane (OCM) obtained from (1) transient experiments and (2) a microkinetic analysis are summarized.The interaction of methane and oxygen with MgO and Sm2O3 surfaces was investigated by applying H/D- and oxygen-isotope-exchange reactions.The role of short-lived adsorbed oxygen species in methane activation and product formation over MgO and Sm2O3 catalysts is discussed.Furthermore, elementary reaction steps and their rate constants are derived for the oxidative conversion of methane to COx and ethane from kinetic data for different (CaO)x(CeO2)1-x catalysts; the rate constants are related to the solid's properties, i.e., electron and O(2-) conductivity.

Oxidative Coupling of Methane over Tin-containing Rare-earth Pyrochlores

Ashcroft, Alexander T.,Cheetham, Anthony K.,Green, Malcolm L. H.,Grey, Clare P.,Vernon, Patrick D. F.

, p. 1667 - 1669 (1989)

Rare-earth pyrochlores of general formula Ln2Sn2O7 (Ln=rare-earth) are found to be active catalysts for the oxidative coupling of methane, with enhanced conversion to useful hydrocarbons, particularly ethene, being observed at 1150 K for those rare-earths

Norman,Pitt

, p. 6104 (1955)

Bradley,Kistiakowsky

, p. 264,265, (1961)

CATALYSTS FOR THE OXIDATIVE CONDENSATION OF METHANE TO FORM C2 HYDROCARBONS

Minachev, Kh. M.,Usachev, N. Ya.,Khodakov, Yu. S.,Kozlov, L. L.,Udut, V. N.,Fomin, O. A.

, p. 1544 (1985)

-

Reactions of Ethanethiol on Mo(110): Formation and Decomposition of a Surface Alkyl Thiolate

Roberts, Jeffrey T.,Friend, C. M.

, p. 5205 - 5213 (1988)

The reactions of ethanethiol C2H5SH on Mo(110) under ultrahigh vacuum have been investigated by temperature-programmed reaction, X-ray photoelectron, and high-resolution electron energy loss spectroscopies.Electron energy loss spectroscopy indicates that the S-H bond in ethanethiol dissociates below 120 K to form a surface ethyl thiolate (C2H5S).At low coverages the ethyl thiolate decomposes to atomic carbon, atomic sulfur, and gaseous H2, with decomposition complete below 350 K.At high coverages, the surface thiolate decomposes during temperature-programmed reaction via three competing pathways: hydrogenolysis at 300 K to gaseous ethane, dehydrogenation at 340 K to gaseous ethylene, and decomposition to surface carbon, surface sulfur, and gaseous dihydrogen.Notably, the presence of surface atomic sulfur is not necessary for selective formation on clean Mo(110): the thiolate remains intact up to the temperature of hydrogenolysis onset.The last pathway proceeds via a hydrocarbon fragment(s) which decomposes at 570 K to gaseous H2 and atomic carbon.At saturation, ca. 75percent of all irreversibly chemisorbed ethanethiol forms gaseous hydrocarbons.The coverage-dependent kinetics for ethanethiol decomposition are discussed in terms of electronic and site-blocking effects.

Kinetics and mechanism of ethylene hydrogenation poisoned by CO on silica-supported monodisperse Pt nanoparticles

Rioux, Robert M.,Komor, Russell,Song, Hyunjoon,Hoefelmeyer, James D.,Grass, Michael,Niesz, Krisztian,Yang, Peidong,Somorjai, Gabor A.

, p. 1 - 11 (2008)

The influence of particle size on the poisoning of ethylene hydrogenation by CO was studied over a series of catalysts composed of nearly monodisperse Pt nanoparticles (1.7-7.1 nm) encapsulated in mesoporous silica (SBA-15). The turnover frequency at 403 K in the presence of 0.5 Torr CO was ~2 × 10-2 s-1 (compared with ~102 s-1 in the absence of CO). The apparent activation energy in the absence and presence of 0.2 Torr CO was ~10 and 20 kcal mol-1, respectively. The pressure dependency changes significantly in the presence of CO; reaction orders in hydrogen were 1/2 in the presence of CO at 403 K and noncompetitive with regard to co-adsorption with C2H4. In the absence of CO at similar temperatures, H2 adsorption was primarily irreversible (first-order dependence), and H2 and C2H4 compete for the same sites. Ethylene orders at 403 K were first order in the presence of 0.2 Torr CO and remained unity with increasing CO pressure. At similar reaction conditions in the absence of CO, ethylene had an inhibitory effect (negative reaction order) on the overall hydrogenation reaction. The change in C2H4 and H2 kinetics suggests strong competitive adsorption between C2H4 and CO for the same type of site, whereas H2 apparently adsorbs on distinct surface sites due either to steric hindrance or H2-induced CO desorption. Incorporation of a quasi-equilibrated CO adsorption step into a noncompetitive Langmuir-Hinshelwood mechanism predicts the experimentally observed pressure dependencies and a doubling of the apparent activation energy. Hydrogenation of ethylene in the presence of 1 Torr CO was examined under reaction conditions at 403 K by infrared spectroscopy; the only surface species identified under reaction conditions was linear-bound CO. The hydrogenation of ethylene on clean Pt catalysts was structure-insensitive and remains insensitive in the presence of CO; rates decreased only by a factor of two with increasing particle size.

Oxidative Coupling of Methane with Alkaline Earth Halide Catalysts Supported on Alkaline Earth Oxides

Fujimoto, Kaoru,Hashimoto, Shigeru,Asami, Kenji,Tominaga, Hiro-o

, p. 2157 - 2160 (1987)

Halides of alkaline earth metal oxides such as MgCl2 or CaCl2 on CaO or on MgO were found to be excellent catalysts for the oxidative coupling of methane.The selectivity of C2 hydrocarbon reached 87percent at 750 deg C and CH4/O2=9.

Oxidative Coupling of Methane over BaO Mixed with CaO and MgO

Yamagata, Nobutsugu,Tanaka, Katsutoshi,Sasaki, Shoichi,Okazaki, Susumu

, p. 81 - 82 (1987)

Various metal oxides mixed with BaO were studied as a catalyst for coupling of methane.For example, a BaO-CaO catalyst shows a high activity (20.9 mmol/hg) for the C2 formation (C2H6+C2H4) with a high C2 selectivity (61.1percent) under the following conditions; 1073 K, P(CH4)=40 kPa, a ratio of CH4 to O2 = 5.0, and W/F = 3.39 gh/mol.

Bacterial Organomercurial Lyase: Novel Enzymatic Protonolysis of Organostannanes

Walts, Alan E.,Walsh, Christopher T.

, p. 1950 - 1953 (1988)

Pure bacterial organomercurial lyase has been found to catalyze a protonolytic cleavage of the carbon-tin bond in certain organostannanes.Of the compounds tested tetravinyltin is turned over with the highest specific activity, yielding ethylene as the organic product.Similarly, triethylvinyltin undergoes turnover by the lyase to yield ethylene and ethane in a 97:3 ratio, at 1/60th the rate of tetravinyltin turnover.Finally, tetramethyltin and trimethyltin fluoride yield small amounts of methane (2-5 turnovers/mol of enzyme) prior to eventual loss of enzyme activity.The decrease in activity observed during turnover of the organostannanes is consistent with the observed inhibition of the enzyme by dimethyltin dibromide.

Acetylene Hydrogenation to Ethylene in a Hydrogen-Rich Gaseous Mixture on a Pd/Sibunit Catalyst

Shlyapin,Glyzdova,Afonasenko,Temerev,Tsyrul’nikov

, p. 446 - 452 (2019)

Abstract: The reaction of the gas-phase hydrogenation of acetylene on a Pd/Sibunit catalyst was studied depending on the H2 : C2H2 molar ratio, the process temperature, and the presence of carbon monoxide. It was shown that for the reaction mixture of the composition H2 : C2H2 2 : C2H2 > 20, on the contrary, the order in hydrogen becomes zero and the reaction rate is determined by the acetylene content in the reaction mixture. It was found that an increase in the reaction temperature (from 30 to 85°C) leads to an increase in the contribution of complete hydrogenation to ethane. The introduction of CO into the reaction mixture up to a molar ratio of CO : C2H2 = 0.1 is accompanied by the almost complete blocking of the C2H4 readsorption sites, which results in a sharp increase in ethylene selectivity from 4 to 73%. With a further increase in the CO : C2H2 ratio, the number of sites available for hydrogen adsorption gradually decreases, and, correspondingly, the conversion decreases.

The Protolysis of Hexanes over a USHY Zeolite

Bassir, M.,Wojciechowski, B. W.

, p. 1 - 8 (1994)

Detailed information gathered on the cracking of five hexane isomers has revealed major differences in the mechanisms of cracking in the individual isomers and suggests the possibility that synergistic effects play a role in the cracking of mixtures of hydrocarbons.We find that both n-hexane and 2,2-dimethylbutane do not crack via the chain process to any significant extent, presumably due to the absence of tertiary hydrogens in both molecules.On the other hand, 2,3-dimethylbutane, with two tertiary hydrogens, cracks readily via a chain process.The two monomethyl pentanes illustrate the fact that tertiary hydrogens are not all the same in terms of reactivity. 3-methylpentane has a much more reactive hydrogen than 2-methylpentane, with the result that more of this feed is converted by chain processes.However, the overall rate of conversion is higher in 2-methylpentane and lower in 2,3-dimethylbutane.It seems that, when it comes to maximizing the overall rate of reaction, the dominant influence is the rate of initiation by protolysis.In this work we examine the initiating protolysis reactions of the partent hexane molecules.These reactions start the chain processes which, in various measures, are responsible for the observed overall conversion in "catalytic cracking".We find that the rates and modes of the various protolysis reactions are profoundly different in the five isomeric hexanes.In discussing this fact we raise the issue of the significance of "test reactions" in catalyst evaluation.

Efficient Polyester Hydrogenolytic Deconstruction via Tandem Catalysis

Kratish, Yosi,Marks, Tobin J.

supporting information, (2021/12/22)

Using a mechanism-based solvent-free tandem catalytic approach, commodity polyester plastics such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) are rapidly and selectively deconstructed by combining the two air- and moisture-stable catalysts, Hf(OTf)4 and Pd/C, under 1 atm H2, affording terephthalic acid (or naphthalene dicarboxylic acid for PEN) and ethane (or butane for PBT) in essentially quantitative yield. This process is effective for both laboratory grade and waste plastics, and comingled polypropylene remains unchanged. Combined experimental and DFT mechanistic analyses indicate that Hf(OTf)4 catalyzes a mildly exergonic retro-hydroalkoxylation reaction in which an alkoxy C?O bond is first cleaved, yielding a carboxylic acid and alkene, and this process is closely coupled to an exergonic olefin hydrogenation step, driving the overall reaction forward.

Investigation on the Thermal Cracking and Interaction of Binary Mixture of N-Decane and Cyclohexane

Chen, Xuejiao,Pang, Weiqiang,Wang, Bo,Zhang, Ziduan,Zhou, Lingxiao,Zhu, Quan

, (2022/03/02)

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.]

Conversion of Phenol and Lignin as Components of Renewable Raw Materials on Pt and Ru-Supported Catalysts

Bobrova, Nataliia A.,Bogdan, Tatiana V.,Bogdan, Viktor I.,Koklin, Aleksey E.,Mishanin, Igor I.

, (2022/03/01)

Hydrogenation of phenol in aqueous solutions on Pt-Ni/SiO2, Pt-Ni-Cr/Al2 O3, Pt/C, and Ru/C catalysts was studied at temperatures of 150–250? C and pressures of 40–80 bar. The possibility of hydrogenation of hydrolysis lignin in an aqueous medium in the presence of a Ru/C catalyst is shown. The conversion of hydrolysis lignin and water-soluble sodium lignosulfonate occurs with the formation of a complex mixture of monomeric products: a number of phenols, products of their catalytic hydrogenation (cyclohexanol and cyclohexanone), and hydrogenolysis products (cyclic and aliphatic C2 –C7 hydrocarbons).

Symmetry-Broken Au–Cu Heterostructures and their Tandem Catalysis Process in Electrochemical CO2 Reduction

Jia, Henglei,Yang, Yuanyuan,Chow, Tsz Him,Zhang, Han,Liu, Xiyue,Wang, Jianfang,Zhang, Chun-yang

, (2021/04/27)

Symmetry-breaking synthesis of colloidal nanocrystals with desired structures and properties has aroused widespread interest in various fields, but the lack of robust synthetic protocols and the complex growth kinetics limit their practical applications. Herein, a general strategy is developed to synthesize the Au–Cu Janus nanocrystals (JNCs) through the site-selective growth of Cu nanodomains on Au nanocrystals, which is directed by the substantial lattice mismatch between them, with the assistance of judicious manipulation of the growth kinetics. This strategy can work on Au nanocrystals with different architectures for the achievement of diverse asymmetric Au–Cu hybrid nanostructures. Of particular note, the obtained Au nanobipyramids (Au NBPs)-based JNCs facilitate the conversion of CO2 to C2 hydrocarbon production during electrocatalysis, with the Faradaic efficiency and maximum partial current density being 4.1-fold and 6.4-fold higher than those of their monometallic Cu counterparts, respectively. The excellent electrocatalytic performances benefit from the special design of the Au–Cu Janus architectures and their tandem catalysis mechanism as well as the high-index facets on Au nanocrystals. This research provides a new approach to synthesize various hybrid Janus nanostructures, facilitating the study of structure-function relationship in the catalytic process and the rational design of efficient heterogeneous electrocatalysts.

Coupling conversion of methane with carbon monoxideviacarbonylation over Zn/HZSM-5 catalysts

Wen, Fuli,Zhang, Jin,Chen, Zhiyang,Zhou, Ziqiao,Liu, Hongchao,Zhu, Wenliang,Liu, Zhongmin

, p. 1358 - 1364 (2021/03/14)

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.

Process route upstream and downstream products

Process route

4,4-dimethyl-azetidin-2-one
4879-95-2

4,4-dimethyl-azetidin-2-one

2,2-dimethylaziridine
2658-24-4

2,2-dimethylaziridine

ethane
74-84-0

ethane

carbon monoxide
201230-82-2

carbon monoxide

Conditions
Conditions Yield
at 149.9 ℃; under 28.5 Torr; Product distribution; Quantum yield; Mechanism; Irradiation; mercury-photosensitized decomposition; other pressures (640 - 5000 Pa), different light intensities;
spiro[2.5]octane
185-65-9

spiro[2.5]octane

vinylcyclohexane
695-12-5,25498-06-0

vinylcyclohexane

ethane
74-84-0

ethane

ethene
74-85-1

ethene

ethylidenecyclohexane
1003-64-1

ethylidenecyclohexane

Conditions
Conditions Yield
at 176.9 ℃; for 0.75h; Product distribution; Mechanism; also laser-powdered decomposition;
ethyl iodide
75-03-6

ethyl iodide

ethane
74-84-0

ethane

ethene
74-85-1

ethene

hydrogen iodide
10034-85-2

hydrogen iodide

Conditions
Conditions Yield
mit UV-Licht; Produkt5: Wasserstoff.Irradiation;
at 25 ℃; mit Licht (lambda: 253.7 mmy); weitere Produkte: Methan und Wasserstoff.Irradiation;
at 25 ℃; mit Licht (lambda: 202.6 mmy); weitere Produkte: Methan und Wasserstoff.Irradiation;
Photolysis;
ethanol
64-17-5

ethanol

ethyl iodide
75-03-6

ethyl iodide

ethane
74-84-0

ethane

ethene
74-85-1

ethene

hydrogen iodide
10034-85-2

hydrogen iodide

Conditions
Conditions Yield
Irradiation;
ethyl iodide
75-03-6

ethyl iodide

ethane
74-84-0

ethane

ethene
74-85-1

ethene

hydrogen iodide
10034-85-2

hydrogen iodide

Conditions
Conditions Yield
Photolysis;
ethane
74-84-0

ethane

ethylbenzene
100-41-4,27536-89-6

ethylbenzene

Conditions
Conditions Yield
In benzene; at 70 ℃; Yields of byproduct given;
water
7732-18-5

water

pyrographite
7440-44-0

pyrographite

calcium oxide

calcium oxide

ethane
74-84-0

ethane

carbon dioxide
124-38-9,18923-20-1

carbon dioxide

hydrogen
1333-74-0

hydrogen

calcium carbonate

calcium carbonate

Conditions
Conditions Yield
at 650 ℃; for 2h; under 38002.6 Torr;
78%
2.7%
2%
Conditions
Conditions Yield
at 1000 - 1100 ℃; under 820.855 Torr;
12.6 %Chromat.
3.39 %Chromat.
26 %Chromat.
0.35 %Chromat.
0.49 %Chromat.
15.1 %Chromat.
4.02 %Chromat.
3.65 %Chromat.
2.95 %Chromat.
4.85 %Chromat.
2.33 %Chromat.
0.77 %Chromat.
aluminum oxide; iron(III) oxide; at 1000 - 1100 ℃; under 820.855 Torr;
16.53 %Chromat.
4.01 %Chromat.
31.78 %Chromat.
0.49 %Chromat.
0.5 %Chromat.
16.02 %Chromat.
4.71 %Chromat.
0.76 %Chromat.
0.54 %Chromat.
4.2 %Chromat.
3.05 %Chromat.
1.06 %Chromat.
Conditions
Conditions Yield
zeolite ZSM-5; at 550 ℃; under 1500.15 Torr;
0.41%
1.22%
4.59%
2.24%
40.79%
11.83%
3.57%
6.01%
25.26%
Conditions
Conditions Yield
With zeolite ZSM-5; at 550 ℃; under 1500.15 Torr;
0.24%
0.73%
4.87%
2.13%
18.17%
7.03%
2.12%
3.57%
59.03%
zeolite ZSM-5; at 550 ℃; under 1500.15 Torr;
0.39%
1.15%
5.2%
2.24%
28.73%
11.11%
3.35%
5.65%
37.4%

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