F:Flammable;
110-83-8Relevant articles and documents
Vaughan,Craven
, p. 4629,4630, 4631 (1955)
Monolithic materials: New high-performance supports for permanently immobilized metathesis catalysts
Mayr, Monika,Mayr, Betina,Buchmeiser, Michael R.
, p. 3839 - 3842 (2001)
Back to the roots: Ring-opening metathesis polymerization allows the synthesis of monolithic materials, which may be subject to an in situ derivatization with dihydroimidazolium salts through metathesis graft polymerization. This method offers an attracti
DIRECT PHOTOLYSIS AT 185 nm OF SIMPLE CYCLOBUTENES. MOLECULAR ELIMINATION OF ACETYLENE
Inoue, Yoshihisa,Sakae, Mitsuhiro,Hakushi, Tadao
, p. 1495 - 1498 (1983)
Direct photolyses at 185 nm of bicyclohept-6-ene and bicyclooct-7-ene in pentane afforded acetylene and the fragment cycloalkenes as the major photoproducts, whereas the Woodward-Hoffmann allowed ring-opening giving rise to 1,3-diene was a minor process.
Slaugh,Raley
, p. 2861,2863 (1967)
Molybdenum Imido Alkylidene N-Heterocyclic Carbene Complexes: Structure–Productivity Correlations and Mechanistic Insights
Buchmeiser, Michael R.,Sen, Suman,Lienert, Christina,Widmann, Laura,Schowner, Roman,Herz, Katharina,Hauser, Philipp,Frey, Wolfgang,Wang, Dongren
, p. 2710 - 2723 (2016)
The syntheses and single-crystal X-ray structures of a series of Mo–imido alkylidene N-heterocyclic carbene (NHC) complexes (1–15) and of the first complexes containing bidentate NHC-phenolate ligands (16–18) are reported. Mo(N-2,6-Me2-C6H3)((1-R-phenethyl)-3-mesitylimidazolidin-2-ylidene)(CHR)(OTf)2 (R=CMe2Ph, 1) is the first enantiomerically pure Mo–imido alkylidene NHC catalyst. With [Mo(N-2,6-Me2-C6H3)(IMes)(CHR)(CH3CN)(OTf)(CH3CN)+ B(ArF)4?] (7), turnover numbers up to 545 000 were achieved in the homometathesis (HM) of 1-octene and 1-nonene (≤95 percent E). With 7 and 1-nonene, a turnover frequency (TOF4 min) of 8860 min?1 was determined. Productivity and E/Z-selectivity were correlated with catalyst structure. For 1, Mo(N-3,5-Me2-C6H3)(IMesH2)(CHR)(OTf)2 (9) and Mo(N-3,5-Me2-C6H3)(IMes)(CHR)(OTf)2 (10), productivity was correlated with the coalescence temperature of the two triflates, determined by variable-temperature 19F NMR spectroscopy. The square-planar conformer is postulated to be the most relevant for the catalyst activation.
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Clive,D.L.J.,Menchen,S.M.
, p. 658 - 659 (1977)
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Benkeser,Kaiser
, p. 2858 (1963)
The Nature of the Preferred Chain-carrying Metallacarbene Intermediate in Metathesis Reactions Involving Alk-1-enes
Bencze, Lajos,Ivin, Kenneth J.,Rooney, John J.
, p. 834 - 835 (1980)
The minor products from the cross-metathesis of norbornadiene (NBD) with hex-1-ene and of cyclopentene (CP) with octa-1,7-diene (1,7-OD), respectively, show that the complexed alkylidenes, RCH= (where denotes the metal site with the ligands attached), are much preferred to the complexed methylene, CH2=, as chain carriers formed by the reactions of the terminal olefins; but CH2=, when formed, is highly reactive towards the latter, with the strongly electrophilic methylene ligand selectively adding to the terminal olefins at the C-1 position.
The syntheses of carbamates from reactions of primary and secondary aliphatic amines with dimethyl carbonate in ionic liquids
Sima, Tianlong,Guo, Shu,Shi, Feng,Deng, Youquan
, p. 8145 - 8147 (2002)
At 170°C and using ionic liquids as solvent and catalyst, primary and secondary aliphatic amines could react with dimethyl carbonate to give alkyl carbamates with good yield. Due to its insolubility, the desired carbamate solid could be recovered by simpl
Platinum complexes of a boron-rich diphosphine ligand
Bowes, Eric G.,Drover, Marcus W.,Dufour, Maeve C.,Lesperance-Nantau, Lindsay A.
, p. 16312 - 16318 (2020)
Herein, we describe the preparation, characterization, and reactivity of two PtII bis-hydrocarbyl complexes containing the 1,2-bis(di(3-dicyclohexylboraneyl)propylphosphino)ethane (P2BCy4) ligand. These scaffolds are readily accessed from four-fold hydroboration of 1,2-bis(diallylphosphino)ethane PtII precursors. The electrophilcity of such frameworks is showcased by facile coordination of the strong Lewis base, 4-N,N-dimethylaminopyridine (DMAP). Thermolysis reactions of [Pt(P2BCy4)(R)2] (R = CH3 or Ph) show enhanced (and divergent) reactivity when compared to their all-alkyl diphosphine counterparts, implicating involvement of the pendant borane groups. This behaviour is attenuated by protection of these units with DMAP.
Effect of organic additives on the performance of nano-sized Ru-Zn catalyst
Sun, Haijie,Chen, Zhihao,Guo, Wei,Zhou, Xiaoli,Liu, Zhongyi,Liu, Shouchang
, p. 369 - 373 (2011)
A novel Ru-Zn catalyst was prepared by coprecipitation. The catalyst was characterized by XRF, XRD and TEM. The effects of organic additives on the performance of the Ru-Zn catalyst for benzene selective hydrogenation to cyclohexene were investigated. The results showed that the catalyst was composed of Ru and Zn in molar ratio of 33.8:1, and the most probable value of the Ru crystallite size in the catalyst was 5.1 nm. The modification of Ru with Zn and the small size effect were the main cause why the catalyst exhibited the high activity and the excellent cyclohexene selectivity. When PEG (polyethylene glycol) was used as an additive, the activity of the catalyst decreased, and the cyclohexene selectivity increased with the increase of the PEG molecular weight. With the addition of PEG-20000, a cyclohexene selectivity of 78.9% at a benzene conversion of 68.7% and a maximum cyclohexene yield of 61.4% were obtained. With diethanolamine and triethanolamine as additives, cyclohexene yields were as high as 58.9% and 58.2%, respectively. Copyright
Reaction of Deuterium Atoms with Cyclohexane on Cu(111): Hydrogen Abstraction Reactions by Eley-Rideal Mechanisms
Xi, Ming,Bent, Brian E.
, p. 4167 - 4172 (1993)
Cyclohexane desorbs molecularly intact from Cu(111) and does not react with deuterium atoms that are preadsorbed on the surface.By contrast, when deuterium atoms formed on a hot tungsten filament are impinged onto a Cu(111) surface precovered with cyclohexane, dehydrogenated products (cyclohexene, cyclohexadiene, and benzene) are evolved when the surface is heated in a subsequent temperature-programmed reaction (TPR) experiment.These D-atom-induced dehydrogenation products provide strong evidence for an Eley-Rideal mechanism where D atoms abstract hydrogen from cyclohexane prior to thermal accommodation with the surface.The kinetics of cyclohexene evolution indicate that both single and sequential H-atom abstractions occur by this mechanism.The cross section for abstraction is on the order of 0.5 Angstroem2/cyclohexane, about an order of magnitude smaller than that for D-atom addition to ?-bonds, consistent with the relative cross sections for these reactions in the gas phase.In addition to these Eley-Rideal-type reactions, there is evidence for Langmuir-Hinshelwood hydrogenation and dehydrogenation reactions during the TPR experiment.Product distributions in the desorbing flux were quantified by mass spectrometry using an electron-impact ionization energy of 15 eV to accentuate the molecular ions.
Synthesis, characterization, reactivity, and catalytic hydrogenation activity of the hexanuclear hexahydrido carbonyl cluster compound 3,η2-ampy)2(CO)14> (Hampy = 2-amino-6-methylpyridine)
Cabeza, Javier A.,Rio, Ignacio del,Fernandez-Colinas, Jose M.,Llamazares, Angela,Riera, Victor
, p. 169 - 178 (1995)
The reaction of the 48-electron complex 3,η2-ampy)(CO)9> (1) (Hampy = 2-amino-6-methylpyridine) with molecular hydrogen (1 atm, toluene, 110 deg C) gives the 92-electron hexanuclear hexahydrido derivative 3,η2-ampy)2(CO)14> (2).This hexanuclear compound regenerates complex 1 when exposed to carbon monoxide.However, it undergoes CO substitution instead of ligand addition when treated with PR3 to give 3,η2-ampy)2(PR3)2(CO)12> (R = 4-tolyl (3a) or Ph (3b)).The X-ray diffraction structure of 3a indicates that it consists of two trinuclear fragments connected to each other through two bridging hydrides, and two weak metal-metal bonds.NMR experiments (1H, 13C, homonuclear 1H NOE, and heteronuclear indirect 13C-1H correlations) indicate that 2 is isostructural with 3a.Complex 2 is an efficient catalyst precursor for the homogeneous hydrogenation of unsaturated organic molecules.A kinetic analysis of the hydrogenation of diphenylacetylene under very mild conditions (T = 323 K, P(H2)1 atm) has shown that the reaction is first-order in the concentration of 2, first-order in hydrogen pressure and zero-order in substrate concentration, suggesting that the active catalytic species are hexanuclear.Keywords: Ruthenium; Hydride; Cluster; X-ray structure; Catalytic hydrogenation; Alkyne hydrogenation kinetics
Photon can tremendously accelerate the alkyl iodides' elimination in water
Liu, Wenbo,Li, Chao-Jun
, p. 1699 - 1702 (2015)
Elimination of the alkyl halides in water is very difficult due to the heterogeneous nature and the limitation of base strength. We discovered that ultra-violet (UV) light can enhance the elimination rate of alkyl iodides, including primary, secondary, and tertiary iodides in water dramatically for the first time. We propose a tandem radical-carbocation reaction mechanism to rationalize this special property of alkyl iodides.
Strohmeier,Steigerwald
, p. C37 (1977)
Photocatalysis of RhCl(PCy3)2 for Cyclohexane Dehydrogenation: Thermal Dissociation of C - H Bond and Photoelimination of H2
Itagaki, Hiroaki,Murayama, Hiroki,Saito, Yasukazu
, p. 1254 - 1257 (1994)
Catalytic cyclohexane dehydrogenation, yielding cyclohexane and dihydrogen, proceeded under photoirradiation on either a three-coordinated complex, RhCl(PCy3)2 (Cy = cyclohexyl), or a dihydride complex, RhClH2(PCy3)2, with almost the same turnover frequencies (8.4 or 8.6, respectively) attained by use of a cut-filter (UV-27) under refluxing conditions (354 K).RhCl(PCy3)2 in cyclohexane gave stoichiometric amounts of cyclohexene and RhClH2(PCy3)2 at 354 K; the latter complex yielded little H2 even at 373 K in toluene.A photocatalysis cycle for cyclohexane dehydrogenation with RhCl(PCy3)2 is proposed, where cyclohexene is yielded by thermal C - H bond dissociation and dihydrogen is photoeliminated from RhClH2(PCy3)2, regenerating the original complex.
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Srinivarsan,Ors
, p. 7089 (1978)
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AMINOSULFUR TRIFLUORIDES: RELATIVE THERMAL STABILITY
Messina, Patrica A.,Mange, Kevin C.,Middleton, W. J.
, p. 137 - 144 (1989)
The fluorinating reagent, DAST (diethylaminosulfur trifluoride, 1b), has the potential to decompose violently when heated and presents a hazard if not propely handled.This investigation has shown that the decomposition occurs in two steps.First, a non-ene
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Floutz
, (1945)
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White,Scherrer
, p. 758,759 (1961)
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Johnson,R.A.,Nidy,E.G.
, p. 1680 - 1681 (1975)
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Shenton,Johnson
, p. 1461,1464 (1971)
Reaction of thianthrene cation radical with alcohols: Cyclohexanols
Shine, Henry J.,Yueh, Wang
, p. 6583 - 6586 (1992)
Cyclohexanol (1), 4-methylcyclohexanol (2), 4-tert-butylcyclohexanol (3), cis-2-methyl- (4) and trans-2-methylcyclohexanol (5) reacted cleanly with thianthrene cation radical perchlorate (Th·+ClO4-) in the presence of 2,6-di-tert-butyl-4-methylpyridine (DTBMP). The alcohols were converted quantitatively into cyclohexenes, while Th·+ was converted quantitatively into thianthrene (Th) and thianthrene 5-oxide (ThO). The oxygen atom of ThO came from the alcohol, as was demonstrated with the use of [18O]cyclohexanol.
C-N bond hydrogenolysis of aniline and cyclohexylamine over TaO:X-Al2O3
Bachrach, Mark,Marks, Tobin J.,Notestein, Justin M.
, p. 6001 - 6004 (2016)
TaOx grafted onto Al2O3 is investigated for C-N bond cleavage of amines under H2 pressure. Heteroaromatics such as aniline are stoichiometrically denitrogenated at high temperature, while cyclohexylamine is catalytically denitrogenated. UV-visible and X-ray photoelectron spectroscopy indicate the formation of a stable Ta-N species in the former case.
HALOGEN-EXCHANGE FLUORINATION OF CYCLO AND TERTIARY ALKYL HALIDES USING Cu2O-HF-ORGANIC BASE SOLUTIONS
Yoneda, Norihiko,Fukuhara, Tsuyoshi,Nagata, Seiji,Suzuki, Akira
, p. 1693 - 1694 (1985)
Cu2O-HF-Organic base (tetrahydrofuran or Et2O) solutions were used successively as a highly reactive halogen-exchange fluorination reagent for the cyclo or tertiary alkyl halides without carbon skeletal rearrangement under the mild conditions.
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).
Hydroxycarbonylation of alkenes with formic acid using a rhodium iodide complex and alkyl ammonium iodide
Okada, Masaki,Takeuchi, Katsuhiko,Matsumoto, Kazuhiro,Oku, Tomoharu,Choi, Jun-Chul
supporting information, p. 8727 - 8734 (2021/10/22)
Hydroxycarbonylation of alkenes using formic acid (HCOOH) is ideal for the synthesis of various carboxylic acids as a means to develop a sustainable reaction system with lower environmental impact. In this study, we developed a new catalytic system for hydroxycarbonylation of alkenes with HCOOH using a Vaska-type Rh complex with an iodide ligand, RhI(CO)(PPh3)2(1), as the catalyst, and a quaternary ammonium iodide salt as the promoter for the catalyst. In comparison with similar reaction systems using Rh catalysts, our reaction system is safer and more environmentally friendly since it does not require high-pressure conditions, explosive gases, or environmentally unfriendly CH3I and extra PPh3promoters. In addition, we also experimentally clarified that the catalytic reaction proceedsviaRhHI2(CO)(PPh3)2(2), which is formed by the reaction of1with a quaternary ammonium iodide salt andp-TsOH. Furthermore, the Rh(iii) complex2can catalyze hydroxycarbonylation of alkenes with HCOOH without any promoters.
Differences in Mechanism and Rate of Zeolite-Catalyzed Cyclohexanol Dehydration in Apolar and Aqueous Phase
Chen, Feng,Shetty, Manish,Wang, Meng,Shi, Hui,Liu, Yuanshuai,Camaioni, Donald M.,Gutiérrez, Oliver Y.,Lercher, Johannes A.
, p. 2879 - 2888 (2021/03/09)
The rate of acid-base-catalyzed dehydration of alcohols strongly depends on the solvent and the environment of the acid sites. We find that Br?nsted acidic sites in large-pore zeolites, but not in medium-pore zeolites, catalyze cyclohexanol dehydration in decalin at significantly higher rates than hydrated hydronium ions in aqueous phase. Specifically, the difference in turnover rates between the two solvents amounts to 2-3 orders of magnitude on H-BEA and H-FAU, while being very modest (within a factor of 2) for H-MFI. Combining kinetic, isotopic tracer, and 2H NMR measurements, it is established that cyclohexanol dehydration generally follows an E1-elimination pathway in decalin. A notable exception is the monomer dehydration route on H-MFI, which exhibits a much lower activation energy and a substantially negative activation entropy that appear to be associated with an E2-type mechanism. The C-O bond cleavage displays a dominant degree of rate control in decalin, which stands in contrast to deprotonation (C-H cleavage) being rate-limiting in aqueous-phase dehydration.
