590-18-1Relevant articles and documents
Stereospecific Heteroatom and Hetero Group Transfer from Oxiranes, Thiiranes, and Aziridines by a Simple Alkyl Tantalocene
Proulx, Grant,Bergman, Robert G.
, p. 7953 - 7954 (1994)
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Alkali metals on nanoporous carbon: New solid-base catalysts
Stevens, Mark G.,Foley, Henry C.
, p. 519 - 520 (1997)
Caesium entrapped in nanoporous carbon is not pyrophoric, is thermally stable towards desorption up to 773 K, but retains its ability to produce hydrogen from water, and is a strong basic catalyst, providing a greater than 9:1 ratio of the less stable cis-but-2-ene over the trans isomer in the isomerization of but-1-ene at 273 K.
Solid-State Molecular Organometallic Catalysis in Gas/Solid Flow (Flow-SMOM) as Demonstrated by Efficient Room Temperature and Pressure 1-Butene Isomerization
Furfari, Samantha K.,Martínez-Martínez, Antonio J.,Royle, Cameron G.,Suriye, Kongkiat,Weller, Andrew S.
, p. 1984 - 1992 (2020)
The use of solid-state molecular organometallic chemistry (SMOM-chem) to promote the efficient double bond isomerization of 1-butene to 2-butenes under flow-reactor conditions is reported. Single crystalline catalysts based upon the σ-alkane complexes [Rh(R2PCH2CH2PR2)(η2η2-NBA)][BArF 4] (R = Cy, tBu; NBA = norbornane; ArF = 3,5-(CF3)2C6H3) are prepared by hydrogenation of a norbornadiene precursor. For the tBu-substituted system this results in the loss of long-range order, which can be re-established by addition of 1-butene to the material to form a mixture of [Rh(tBu2PCH2CH2PtBu2)(cis-2-butene)][BArF 4] and [Rh(tBu2PCH2CH2PtBu2)(1-butene)][BArF 4], in an order/disorder/order phase change. Deployment under flow-reactor conditions results in very different on-stream stabilities. With R = Cy rapid deactivation (3 h) to the butadiene complex occurs, [Rh(Cy2PCH2CH2PCy2)(butadiene)][BArF 4], which can be reactivated by simple addition of H2. While the equivalent butadiene complex does not form with R = tBu at 298 K and on-stream conversion is retained up to 90 h, deactivation is suggested to occur via loss of crystallinity of the SMOM catalyst. Both systems operate under the industrially relevant conditions of an isobutene co-feed. cis:trans selectivites for 2-butene are biased in favor of cis for the tBu system and are more leveled for Cy.
Features of Butene-1 Adsorption on H-Beta Zeolite
Volnina,Kipnis,Khadziev
, p. 177 - 180 (2019)
Abstract: The adsorption of butene-1 on Beta zeolite (H form) is studied via flow-adsorption calorimetry. Upon feeding a mixture of 2 vol % of butene-1 in nitrogen over the pre-calcined zeolite (500°C) at room temperature, an exothermic effect is observed that is associated with the adsorption and transformations of butene, particularly its isomerization to cis- and trans-butenes-2. The thermal desorption of adsorbed butene?1 results in formation of hydrocarbon products showing that oligomerization proceeds during adsorption. It is found that zeolite pretreated with moist nitrogen adsorbs water up to 9.2 wt %. A?weak exothermic effect is observed when butene-1 is adsorbed on this rehydrated zeolite, due apparently to the physical adsorption of butene-1. When the rehydrated zeolite is held for long periods of time in a stream of a butene/nitrogen mixture, cis-butene-2 is detected at the reactor outlet, indicating the gradual replacement of water with butene-1 on the active sites of zeolite.
SUPERBASICITY OF RUBIDIUM OXIDE AND CAESIUM OXIDE, AND THEIR REACTION PROFILES OF ISOMERIZATION OF BUTENES
Tsuchiya, Susumu,Takase, Shigeyuki,Imamura, Hayao
, p. 661 - 664 (1984)
The superbasic sites on a rubidium oxide and a caesium oxide have been revealed by means of the benzoic acid titration method.The double-bond-migration and the cis-trans isomerization of butenes took place over the rubidium oxide and the caesium oxide; but the skeletal isomerization was not observed.
CH3-ReO3 on γ-Al2O3: Activity, selectivity, active site and deactivation in olefin metathesis
Salameh, Alain,Baudouin, Anne,Soulivong, Daravong,Boehm, Volker,Roeper, Michael,Basset, Jean-Marie,Coperet, Christophe
, p. 180 - 190 (2008)
The active sites (15% of total Re) of CH3ReO3 supported on alumina arise solely from the reaction of the C{single bond}H bond of CH3ReO3 with reactive AlS{single bond}OS sites of a γ-Al2O3 surface to yield [AlSCH2ReO3], whereas the major species, inactive, corresponds to MeReO3 chemisorbed through its oxo ligand(s) on Lewis acid sites of alumina. Monitoring the active sites of CH3ReO3 supported on alumina by solid-state NMR spectroscopy shows that no carbenic signals are observed and that the resting states of the catalyst in the metathesis of propene correspond to μ-methylene and μ-ethylidene species, so that the propagating carbenic species are likely formed only in the presence of olefins. Although this system is highly active in the metathesis of propene, with initial rates similar to some of the best catalysts, it undergoes fast deactivation, which is due to the propene metathesis products, most likely ethene.
Catalytic evidence of formation of water-induced silicomolybdic acid on a MoO3/SiO2 catalyst
Ogata, Atsushi,Kazusaka, Akio,Yamazaki, Akiko,Enyo, Michio
, p. 15 - 18 (1989)
The formation of silicomolybdic acid induced by the preadsorbed or catalytically formed water on MoO3/SiO2 was evidenced by typical heteropoly acid catalysed reactions, isomerization of 1-butene or dehydration of 2-propanol.
ZINC-PHOTOSENSITIZED CIS-TRANS ISOMERIZATION OF 2-BUTENES
Yamamoto, Shunzo,Nobusada, Naoki,Sueishi, Yoshimi,Nishimura, Norio
, p. 723 - 726 (1985)
The zinc-photosensitized isomerization of cis- and trans-2-butenes has been studied.The photostationary cis/trans ratio was found to be about 1/1.5 and to be independent of the 2-butene pressure.
An Infrared Study of Molybdenum Carbonyl-Butadiene Complexes Encaged in a Zeolite. Implication of the Active Molybdenum Carbonyl Species in the Hydrogenation of Butadiene
Okamoto, Yasuaki,Kane, Hiroshige,Imanaka, Toshinobu
, p. 2005 - 2008 (1988)
Molybdenum carbonyls encaged in a NaY zeolite were found to form stable butadiene complexes; Mo(CO)4(C4H6) and Mo(CO)2(C4H6)n (n = 1 or 2).These complexes are implied to deactivate the hydrogenation of C4H6 over molybdenum carbonyls/zeolite catalysts.The active species is proposed to be Mo(CO)3 ads.
Reaction of 1,1,1-trichloroethane with zero-valent metals and bimetallic reductants
Fennelly, Jay P.,Roberts, A. Lynn
, p. 1980 - 1988 (1998)
Information concerning the pathways and products of reaction of 1,1,1- trichloroethane (1,1,1-TCA) with zero-valent metals may be critical to the success of in situ treatment techniques. Many researchers assume that alkyl polyhalides undergo reduction via stepwise hydrogenolysis (replacement of halogen by hydrogen). Accordingly, 1,1,1-TCA should react to 1,1- dichloroethane (1,1-DCA), to chloroethane, and finally to ethane. Experiments conducted in laboratory-scale batch reactors indicate, however, that with zinc, iron, and two bimetallic reductants (nickel-plated iron and copper- plated iron) this simplistic stepwise scheme cannot explain observed results. 1,1,1-TCA was found to react rapidly with zinc to form ethane and 1,1-DCA. Independent experiments confirmed that 1,1-DCA reacts too slowly to represent an intermediate in the formation of ethane. In reactions with iron, nickel/iron, and copper/iron, cis-2-butene, ethylene, and 2-butene were also observed as minor products. Product ratios were dependent on the identity of the metal or bimetallic reductant, with zinc resulting in the lowest yield of chlorinated product. For reactions with iron and bimetallic reductants, a scheme involving successive one-electron reduction steps to form radicals and carbenoids can be invoked to explain the absence of observable intermediates, as well as the formation of products originating from radical or possibly from carbenoid coupling. Information concerning the pathways and products of reaction of 1,1,1-trichloroethane (1,1,1-TCA) with zero-valent metals may be critical to the success of in situ treatment techniques. Many researchers assume that alkyl polyhalides undergo reduction via stepwise hydrogenolysis (replacement of halogen by hydrogen). Accordingly, 1,1,1-TCA should react to 1,1-dichloroethane (1,1-DCA), to chloroethane, and finally to ethane. Experiments conducted in laboratory-scale batch reactors indicate, however, that with zinc, iron, and two bimetallic reductants (nickel-plated iron and copper-plated iron) this simplistic stepwise scheme cannot explain observed results. 1,1,1-TCA was found to react rapidly with zinc to form ethane and 1,1-DCA. Independent experiments confirmed that 1,1-DCA reacts too slowly to represent an intermediate in the formation of ethane. In reactions with iron, nickel/iron, and copper/iron, cis-2-butene, ethylene, and 2-butyne were also observed as minor products. Product ratios were dependent on the identity of the metal or bimetallic reductant, with zinc resulting in the lowest yield of chlorinated product. For reactions with iron and bimetallic reductants, a scheme involving successive one-electron reduction steps to form radicals and carbenoids can be invoked to explain the absence of observable intermediates, as well as the formation of products originating from radical or possibly from carbenoid coupling.
Thermodynamics of the geometrical isomerization of 2-butene and 2-pentene
Kapteijn, F.,Steen, A. J. van der,Mol, J. C.
, p. 137 - 146 (1983)
The use of two different catalysts for the metathesis of alkenes, active in adjoining temperature regions, allowed an accurate determination of the equilibrium constant for the gas-phase cis-trans isomerization of both 2-butene and 2-pentene over the temperature range 250 to 823 K.Because of this broad temperature range, thermodynamic functions of these reactions, viz. ΔG0(g, T), ΔH0(g, T), ΔS0(g, T), and even ΔCp0(g, T), could be evaluated with a higher precision than from thermochemical tables (API, NBS) or from other equilibrium studies.Moreover, the use of recent spectroscopic quantities for 2-butene results in calculat ed values of thermodynamic functions which are more in agreement with our experimental results than the values in the API tables.
Gordon,Hay
, p. 427 (1968)
Basic properties of a KF modified AlPO4-5 molecular sieve
Zhu, Jian Hua,Wang, Ying,Xu, Qin Hua,Hattori, Hideshi
, p. 1889 - 1890 (1996)
Dispersion of KF on AlPO4-5 molecular sieve creates strong basic sites and basic catalytic activity for the isomerization of butenes at 273 K.
HYDROTHERMAL ACTIVATION OF SILICA-ALUMINA FOR BUTENE ISOMERIZATION. A DEVICE TO PREPARE A STANDARD SAMPLE.
Furuyama,Murashita,Yukumoto,Morimoto
, p. 3039 - 3043 (1980)
Three kinds of silica-alumina catalysts were prepared by hydrothermal treatment (heating a sample in hot water) over the range of 25-250 degree C for various periods. It was found that the hydrothermal treatment significantly increased its catalytic activity for butene isomerization. The dependencies of various surface properties (the production ratio of 2-butene isomers, the surface acidity, the surface area, the pore-size distribution, and the shape and size of the catalyst particle) on the hydrothermal conditions and the kind of starting catalyst sample were systematically investigated, too. It is concluded that the increase in the catalyst activity might be due to the progress of the Si/Al isomorphic substitution in the tetrahedral surface silica network. Hot water might serve as a solvent for the cations and facilitate their movements.
ON THE REVERSIBILITY OF METAL CARBENE FORMATION PROCESS IN OLEFIN METATHESIS REACTION OVER MoOx/β-TiO2 CATALYST
Tanaka, Katsumi,Miyahara, Koshiro,Tanaka, Ken-ichi
, p. 623 - 626 (1980)
Co-isomerization of d0- and d8-cis-2-butene was carried out on a novel catalyst, MoOx/β-TiO2 (2.9>x>2.3), which is active for olefin metathesis reaction without inter- and intra-molecular hydrogen scrambling of olefins.The ratio, d4/(d0+d8), in produced trans-2-butene was found to be zero at the initial stage of the reaction, indicating a type of cis-trans isomerization by intra-molecular metathesis.
Synthesis and Structural Characterization of an Unusual Platinum π-Arene Complex: (η6-C6H3Me3)Pt[(C2F5)2PMe]Me+
Thapaliya, Bhusan,Debnath, Suman,Arulsamy, Navamoney,Roddick, Dean M.
, p. 4018 - 4022 (2015)
Treatment of cis-(dfmp)2PtMe2 (dfmp = (C2F5)2PMe) with the mesitylenium acid (C6Me3H4)+B(C6F5)4- in 1,2-difluorobenzene cleanly produces an unusually stable arene complex, [(η6-C6Me3H3)Pt(dfmp)(CH3)]+(B(C6F5)4)- (1). Facile arene exchange and competitive binding equilibria have been quantified for mesitylene relative to toluene (K = 0.0030(3)) and durene (K = 20(2)). Reaction of 1 with H2 at 80°C results in hydrogenolysis to form the arene hydride (η6-C6Me3H3)Pt(dfmp)(H)+ (2), while treatment of 1 with CO gives trans-(dfmp)2Pt(CO)Me+ as the major phosphine product. Addition of excess Me3P to 1 results in both arene and dfmp displacement to form (Me3P)3PtMe+. (η6-C6Me3H3)Pt(dfmp)(CH3)+ is a moderately active ethylene dimerization catalyst to form 2-butenes (～7 TO h-1, 20°C). (Chemical Equation Presented).
Novel route of double-bond migration of an olefin without protonated species on ZSM-5 zeolite
Kondo,Domen,Wakabayashi
, p. 5477 - 5479 (1997)
A novel reaction of the double-bond migration (DBM) of 1-butene on Bronsted acid sites (BAS) of zeolites in the absence of proton transfer from BAS to the adsorbed olefin was found. The widely accepted protonated intermediate should result in the conversion of the acidic OD groups to OH upon the DBM. Nevertheless, the OD groups forming a 1:1 complex with the adsorbed 1-butene were unchanged even after the reaction. The isotope exchange of OD groups occurred at a higher temperature than that of the DBM. Thus, the existence of a new type of reaction on BAS is demonstrated, which takes place more easily than the proton transfer.
Accumulation of Potassium Oxide on Carbon and Enhancement of Catalytic Activity for Isomerization by O2
Yokoyama, Shin-ya,Tanaka, Ken-ichi,Seisho, Minoru
, p. 1061 - 1062 (1981)
The concentration of potassium oxide on a carbon surface is changed by contact with oxygen at room temperature, resulting in a marked enhancement in catalytic activity for the isomerization of but-1-ene to cis-but-2-ene.
Silica-Supported Tungsten Neosilyl Oxo Precatalysts: Impact of the Podality on Activity and Stability in Olefin Metathesis
Grekov,Bouhoute,Szeto,Merle,De Mallmann,Lefebvre,Lucas,Del Rosal,Maron,Gauvin,Delevoye,Taoufik
, p. 2188 - 2196 (2016)
In order to establish structure-reactivity relationships in propylene metathesis as a function of the podality of tungsten oxo species bearing neosilyl ligands, we targeted the parent tris alkyl [(≡SiO)WOR3] and bis alkyl oxo [(≡SiO)2WOR2] derivatives prone to carbene formation. Thus, [WO(CH2SiMe3)3Cl] (1) was grafted onto silica dehydroxylated at 700 °C (SiO2-700), proceeding via W-Cl cleavage to yield well-defined monopodal species [(≡SiO)WO(CH2SiMe3)3] (2a) along with HCl release. On the other hand, the corresponding bipodal species [(≡SiO)2WO(CH2SiMe3)2] (2b) was obtained on SiO2-200 by release of both HCl and TMS. The formation of these species were demonstrated by mass balance analysis, elemental analysis, IR, advanced solid-state NMR (1D and 2D 1H, 13C, 29Si, and 17O), and EXAFS. Furthermore, DFT calculations allowed understanding and rationalizing the experimental results regarding grafting selectivity. Materials 2a and 2b proved to lead to stable and efficient supported tungsten oxo catalysts for propene metathesis under dynamic conditions at 80 °C. The symmetric bipodal precatalyst (expressed as [W(=E)(=CHR)(X)(Y)] (X = Y, E = spectator ligand)) showed somewhat higher activity than the asymmetric (X ≥ Y) counterparts.
Kinetics of the Isomerization of But-1-ene on NaHY Zeolites Studied by Infrared Spectroscopy
Datka, Jerzy
, p. 391 - 396 (1981)
The kinetics of but-1-ene isomerization on zeolite with an oligomer was studied by infrared spectroscopy.The product of butene oligomerization is catalytically inactive in but-1-ene isomerization.OH groups vibrating at 3640 cm-1 which remain in the zeolite are responsible for the reaction of the zeolite with the oligomer.However, their catalytic activity is very low, because they are not easily accessible to reagent molecules (the oligomer blocks the zeolite channels).At temperatures > 390 K partial decomposition of the oligomer takes place, accessibility of the OH groups vibrating at 3640 cm-1 improves and the zeolite can again catalyse the isomerization.The kinetics of but-1-ene isomerization was also studied at low temperatures.Under these conditions butene oligomerization is avoided and all OH groups vibrating at 3640 cm-1 can participate in the reaction.Over a series of NaHY zeolites the catalytic activity increases with degree of exchange and decreases with the amount of pyridine adsorbed.The acid strength of the OH groups vibrating at 3640 cm-1 changes in the same direction thus indicating that there is a correlation between the acid strength of the groups and their catalytic activity.
Enhanced Metathesis Activity and Stability of Methyltrioxorhenium on a Mostly Amorphous Alumina: Role of the Local Grafting Environment
Zhang, Fan,Szeto, Kai C.,Taoufik, Mostafa,Delevoye, Laurent,Gauvin, Régis M.,Scott, Susannah L.
, p. 13854 - 13868 (2018)
Inorganic oxides play a crucial role in the activation of atomically dispersed metal oxides for catalytic olefin transformations, but the inefficient activation processes remain poorly understood. Activation of methyltrioxorhenium (MTO) for propene metathesis via its deposition on the surface of ?3-Al2O3 typically results in 2O3) results in ca. 4× more activity and at least 10× more productivity. On both types of alumina, metathesis is initiated only at specific sites, whose availability limits the catalytic activity. While the two aluminas have similar total numbers of Lewis acid sites, the less crystalline support activates twice as many grafted MTO sites. Interestingly, a-Al2O3 has nearly double the number of strong Lewis acid sites. However, the number of active sites is ca. 10× lower than the total number of strong Lewis acid sites, and metathesis proceeds even when most are occupied by pyridine. DQSQ and D-HMQC 1H and 27Al solid-state NMR reveal that many Lewis acid sites are co-located with surface hydroxyl groups, which prevent activation and/or cause rapid deactivation. Undercoordinated Al sites on dominant (110) facets, which retain hydroxyl groups under catalyst preparation conditions, are therefore unlikely to lead to stable active sites. In contrast, the minor (100) facets of ?3-Al2O3, which are completely dehydroxylated, contain strongly Lewis-acidic five-coordinate Al sites that are necessarily remote from surface hydroxyl groups. Such sites, which are relatively more abundant on less well-crystallized aluminas, are inferred to be responsible for generating stable metathesis sites.
Selective Catalytic Oxydehydrogenation of Methane to Z-But-2-ene on Cobalt Ferrite
Besoukhanova, Cvetana,Uzunova, Elly,Nenova, Veneta
, p. 485 - 486 (1993)
Oxidative oligomerization of methane proceeds over unpromoted cobalt ferrite catalyst with high yield of Z-but-2-ene.
Tuning crystal phase of molybdenum carbide catalyst to induce the different selective hydrogenation performance
Ding, Ziluo,Hou, Ruijun,Sun, Kening,Xu, Yamei,Yang, Qiuchen
, (2021/12/04)
α-MoC, β-Mo2C, and MoC-Mo2C were synthesized and investigated in the selective hydrogenation of 1,3-butadiene to understand the effect of crystal phases. The catalysts were characterized by XRD, N2-physisorption, SEM, TEM, XPS and chemisorptions. The adsorption properties and electronic properties over MoC(001) and Mo2C(001) were investigated by DFT calculations. The catalysts were evaluated at low and high temperatures in a fixed-bed reactor. β-Mo2C exhibits high activity and low butenes selectivity, due to the high concentration of hydrogen at each active site as well as the stronger adsorption and higher capacity of alkene; MoC-Mo2C shows better stability due to synergetic effect. At high temperature, the reaction rate is more dependent on the PH2 than PC4H6. Increasing PH2 could promote the activity and reduce oligomers formation. β-Mo2C exhibits the best performance at high temperatures concerning its high activity and the inhibition of oligomerization. This work is valuable for the non-precious metal catalyst development.
Selective dehydration of 1-butanol to butenes over silica supported heteropolyacid catalysts: Mechanistic aspect
Dutta, Saikat,Kella, Tatinaidu,Mal, Sib Sankar,Shee, Debaprasad,Vennathan, Anjana Anandan
, (2021/11/03)
Butenes are considered as important olefinic building block to produce fuels/fuel additives and commodity chemicals. In the present investigation, selective dehydration of 1-butanol to butenes was studied in a continuous-flow fixed-bed reactor using various silica-supported heteropolyacid (HPA) catalysts such as phosphotungstic acid (PTA), silicotungstic acid (STA), phosphomolybdic acid (PMA), and silicomolybdic acid (SMA) as the solid acid catalysts. The physicochemical properties of these HPA were determined by BET, powder XRD, FTIR, NH3-TPD, and Py-FTIR. The acid strength and Br?nsted/Lewis (B/L) acid ratio were increased with higher loading of HPA on silica. The nature of HPA (addenda and hetero atom) and loading of HPA are important factors for the dehydration of 1-butanol and selectivity towards butenes. PTA and STA showed superior catalytic activity than PMA and SMA. The reaction temperature and WHSV also strongly affected the butanol conversion and selectivity of butenes. The selectivity of di-n?butyl ether decreases with the rising temperature from 523 K to 623 K. The isomerization of 1-butene leading to the formation of other butene isomers depends on the HPA loading, temperature, and WHSV. The presence of molybdenum addendum atom in PMA and SMA promotes dehydrogenation and hydrogenation, leading to the formation of various light hydrocarbons. The 20PTA/SiO2 catalyst afforded 99.8% selectivity towards butenes at quantitative conversion of 1-butanol, whereas the 20STA/SiO2 catalyst gave nearly 97.0% conversion of 1-butanol and 99.9% butenes selectivity at 673 K, 37.4 h?1 of WHSV.
CATALYTIC HYDROCARBON DEHYDROGENATION
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Paragraph 0063; 0064; 0124; 0125, (2021/03/13)
A catalyst for dehydrogenation of hydrocarbons includes a support including zirconium oxide and Linde type L zeolite (L-zeolite). A concentration of the zirconium oxide in the catalyst is in a range of from 0.1 weight percent (wt. %) to 20 wt. %. The catalyst includes from 5 wt. % to 15 wt. % of an alkali metal or alkaline earth metal. The catalyst includes from 0.1 wt. % to 10 wt. % of tin. The catalyst includes from 0.1 wt. % to 8 wt. % of a platinum group metal. The alkali metal or alkaline earth metal, tin, and platinum group metal are disposed on the support.
