- Facile Hydrodehalogenation with Hydrogen and Pd/C Catalyst under Multiphase Conditions
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A multiphase system consisting of a hydrocarbon solvent, a strong alkaline solution, and a quaternary onium salt, in the presence of a Pd/C catalyst with hydrogen at atmospheric pressure, allows the rapid and progressive displacement of the chlorine atoms from polyhalogenated benzenes.The onium salt in this case constitutes a third liquid phase in which the reaction takes place.At 50 deg C, 1,2,4,5-tetrachlorobenzene is reduced to benzene in 30 min using a Pd/Cl molar ratio of 1/130.Halogenated compounds are partitioned between the hydrocarbon solution and the liquid phase of the phase-transfer agent; rapid removal of HCl adsorbed on Pd/C is effected by neutralization with the alkaline solution.The enhancement of the reaction rate compared with the known methods might be attributed to the facile adsorption of H2 by the catalyst under the reaction conditions.Different reaction rates result in the reduction of the three isomeric chlorotoluenes, whether the reaction is carried out in the presence or absence of the onium salt.
- Marques, Carlos Alberto,Selva, Maurizio,Tundo, Pietro
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- The Photochemistry of Polyhaloarenes. 5. Fragmentation Pathways in Polychlorobenzene Radical Anions
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Negative chemical ionization mass spectroscopy of polychlorobenzenes reveals that parent radical anion undergoes fission by two pathways--(a) cleavage to aryl radical plus Cl- (kCl-) and (b) fission to aryl carbanion plus chlorine atom (kCl*)--and that there is a Hammett relationship between log(kCl*/kCl-) and Σ?.The dependence of the reciprocal of the quantum yield for photochemical dechlorination of trichlorobenzenes through pentachlorobenzene upon the reciprocal of the concentration of the electron donor, triethylamine, was analyzed in order to establish the optimum concentration for radical anion formation.The regiochemistries for the photodechlorination of trichlorobenzenes through pentachlorobenzene in the presence of triethylamine, with and without acetophenone sensitizer, were determined and found to be very similar and quite different from those observed for the direct photolysis in the absence of triethylamine for the comparison cases of 1,2,3,5-tetrachloro- and pentachlorobenzene.The regiochemistry of the fragmentation of polychlorobenzene radical anion to aryl radical plus chloride ion is rationalized in terms of a bent transition state.
- Freeman, Peter K.,Srinivasa, Ramanujan,Campbell, J.-A.,Deinzer, Max L.
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- Photolyses of Polychloro- and Polybromobenzenes. Novel Isomerization in Solvents Resisting against Hydrogen Abstraction
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Polychloro- and polybromobenzenes were photolyzed in acetonitrile and perfluorohexane.Photolyses of polychlorobenzenes in acetonitrile gave isomerized products in addition to dechlorinated products, which appeared exclusively in the photolyses in hexane and other solvents carrying hydrogen atoms active to hydrogen abstraction.The photolyses in perfluorohexane gave isomerized products to a lesser extent.The reaction in this solvent gave predominantly polyhalobiphenyls which are assumed to be produced through coupling.Without exception the isomerized products have the structure which can be expected to be formed via 1,3-migration of chlorine atom, though it is not sure at present whether it takes place actually.The isomerization was shown to proceed intramolecularly.Some evidence and theoretical rationalization in favor of the 1.3-chlorine migration mechanism are given.
- Hirota, Minoru,Nakada, Masahiro
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- Zeolite ZSM-5 and related materials as catalyst in benzene chlorination
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ZSM-5 type zeolites and related high siliceous materials induce addition of chlorine to benzene yielding hexachlorocyclohexanes, whereas Y-type zeolites favour substitution to yield chlorobenzenes.
- Huizinga,Scholten,Wortel,van Bekkum
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- Photo-Rearrangement of Polychlorobenzenes meta-Migration of Chlorine Atom
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Several polychlorobenzenes were irradiated by ultraviolet light (254 nm) in acetonitrile and the products were determined by gas chromatography.In addition to the abstraction of hydrogen atom from the solvent, photo-isomerization was shown to proceed giving isomeric polychlorobenzenes one of which chlorine atoms migrated to meta to the original position.The meta-rearrangement was rationalized by an MNDO calculation on o-chlorophenyl free radical.
- Morisaki, Kenji,Miura, Yasuki,Abe, Kazuhisa,Hirota, Minoru,Nakada, Masahiro
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- Chlorination of Benzene with L-Zeolite Catalyst in the Presence of Oxygen and Various Solvents
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Benzene was chlorinated by using L type zeolite into p-dichlorobenzene (p-DCB) in a high yield in the presence of 1,2-dichloroethane (EDC) and oxygen.
- Nakamura, Tadashi,Shinoda, Kiyonori,Yasuda, Kensei
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- Dechlorination of Polychlorobenzenes over Triiron Tetraoxide in the Presence of Hydrogen Donating Solvents
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Dechlorination of polychlorobenzenes over Fe3O4 was investigated by a pulse micro-reactor technique.Dechlorinations of various polychlorobenzenes in hexane and cyclohexane were carried out in the gas phase at the temperatures ranging from 498 to 623 K.In the presence of such hydrogen donating solvents, dechlorination was shown to proceed almost exclusively.The relative rates of dechlorination were measured by gas chromatography.It was found that the solvents used to dissolve polychlorobenzenes plays a role of a hydrogen donor in this reaction.The different rates among unequivalent chlorine atoms in a molecule were interpreted by the effect of steric acceleration caused by the neighboring chlorine atom(s).The reaction will probably proceed via hydrogenolytic cleavage of C-Cl bonds.
- Hao, Cui Xiang,Nakada, Masahiro,Yamaguchi, Tatsuaki,Fukushi, Sachio,Hirota, Minoru
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- A Desirable Route to Heterodimers of 1,4-Dihalobenzenes and Anthracene and Their Photoproperties and Thermal Properties
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Electronic oxidative bisdecarboxylation of photoadducts of 2,5-dihalo-1,2-dihydrophthalic anhydride and anthracene gave the corresponding energy-rich heterodimers 12 and 13.The quantum yields of the formation of the excited anthracene from 12 and 13 by the irradiation of 280-nm light were 0.65 and 0.25, respectively.We assumed that the heterodimers of 12 and 13 form biradicaloid intermediates during thermal retro cycloaddition and consumed their stored energy without any visible light.However, we observed emission light from 340 to 460 nm through a glass filter and the formation of anthracene using Nd-YAG laser IR light (1.06 μm) by the multiphoton absorption, when fine powders of 12 and 13 were used.
- Kimura, Masaru,Okamoto, Hideki,Kura, Hisatoshi,Okazaki, Ayumi,Nagayasu, Eiji,et al.
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- Dechlorination of lindane, dieldrin, tetrachloroethane, trichloroethene, and PVC in subcritical water
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Pure water has been used to dechlorinate aliphatic organics without the need for catalysts or other additives. Dehydrohalogenation (loss of HCl with the formation of a double bond) occurred at temperatures as low as 105-200 °C for 1,1,2,2-tetrachloroethane, lindane (1,2,3,4,5,6-hexachlorocyclohexane, γ-isomer), and dieldrin (1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-endo, exo-1,4:5,8-dimethanonaphthalene). Complete loss of the parent compounds was achieved in less than 1 h at 150, 200, and 300 °C for 1,1,2,2-tetrachloroethane, lindane, and dieldrin, respectively. The initial dechlorination of lindane had an activation energy of 84 kJ mol-1 with an Arrhenius pre-exponential factor of 1.5 x 106 s-1. Dehydrohalogenation of lindane formed trichlorobenzenes, followed by subsequent hydrolysis and hydride/chloride exchange to form chlorophenols, lower chlorobenzenes, and phenol as the major final product. Reaction of poly(vinyl chloride) at 300 °C for 1 h formed aromatic hydrocarbons ranging from benzene to anthracene and a char residue with a ca. 1:1 carbon-to-hydrogen ratio (mol/mol). The residue contained 1 wt % of chlorine compared to 57 wt % chlorine in the original polymer. All compounds tested yielded chloride ion as the major product (at higher temperatures), indicating that complete dechlorination of some aliphatic organochlorines may be feasible.
- Kubatova, Alena,Lagadec, Arnaud J. M.,Hawthorne, Steven B.
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- Nickel Complexes as Soluble Catalysts for Reductive Dehalogenation of Aromatic Halides
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Nickel(II) complexes 1 and 2 are soluble catalysts for reductive dehalogenation of aromatic bromides and polychlorobenzenes by sodium borohydride at 25-45 deg C in aqueous ethanol, aqueous acetonitrile, or ethanol-acetonitrile.Deuterium incorporation experiments, and rate retardation by added cumene, point to a radical-chain mechanism.Hydrazine can replace borohydride as a source of reducing power.Reactivity toward this reducing system increases with increasing halogen content of the substrate, a finding that parallels prior observations of dechlorination in natural sediments.
- Stiles Martin
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- Thermolysis of hexachlorocyclohexane in a flow-through packed reactor
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Thermolysis of hexachlorocyclohexane in a flow-through packed system in an inert gas atmosphere was studied.
- Kut'in,Gubanova,Zorin,Zanozina,Markova,Suprunova,Bykova
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- Transchlorination of o-Dichlorobenzene and Benzene into Chlorobenzene
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The transchlorination of o-dichlorobenzene (o-DCB) and benzene into chlorobenzene (CB) was carried out in the presence of catalyst at 400 degC. o-C6H4Cl2 + C6H6 = 2 C6H5Cl Noble metal chloride supported on activated charcoal promoted remarkably the transchlorination.
- Shinoda, Kiyonori
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- Photodechlorination of polychlorobenzene congeners in surfactant micelle solutions
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Photochemical reactions of polychlorobenzene congeners in aqueous solutions containing surfactant micelles have been investigated. Photoreduction through photodechlorination was shown to be the main decay pathway in which lesser chlorinated congeners and benzene were formed as intermediates. Final products included H+ and Cl- in approximately stoichiometric amounts. Several hydrogen sources were investigated with sodium borohyride shown to be a promising rate enhancer at elevated concentrations. -Authors
- Wei Chu,Jafvert
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- Palladium on ultradisperse diamond and activated carbon: The relation between structure and activity in hydrodechlorination
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Ultradisperse diamond was studied as a promising carrier for Pd-containing hydrodechlorination catalysts. Transmission electron microscopy, temperature-programmed reduction, and the adsorption method were used to study catalysts on ultradisperse diamond and activated carbon and a commercial catalyst from Fluca. Catalyst activities in multiphase hydrodechlorination of chlorobenzenes were compared. The activity of Pd-containing catalysts on ultradisperse diamond was found to be several orders of magnitude higher than that of Pd catalysts on activated carbon. Nauka/Interperiodica 2007.
- Kachevskii,Golubina,Lokteva,Lunin
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- Catalytic isomerization of dihalobenzenes C6H3X2R in the presence of high-silica zeolites
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Catalytic isomerization of dichloro- and difluorobenzenes was carried out under conditions of a gas-phase reaction occuring in the presence of metallosilicates with the pentasiltype zeolite structure, in which several silicon atoms are isomorphically replaced by Al, Ga, or Fe atoms.A correlation between the acid properties of these zeolites and their ability to induce dihalobenzene isomerization was found. - Key words: isomerization, difluorobenzene, dichlorobenzene, zeolites.
- Lishchiner, I. I.,Plakhotnik, V. A.,Kuzmicheva, A. N.,Mortikov, E. R.
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- Photochemistry of Polyhaloarenes. 9. Characterization of the Radical Anion Intermediate in the Photodehalogenation of Polyhalobenzenes
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The product-determining intermediate in the photodehalogenation of polyhalobenzenes has been characterized by generating excimers and radical anions within a micellar core and by formation of corresponding radical anions by electron transfer from lithium p,p'-di-tert-butylbiphenyl radical anion (LiDBB).The photodechlorination of pentachlorobenzene (1; 254 nm, CH3CN) produces 1,2,3,5-tetrachloro- (2), 1,2,4,5-tetrachloro- (3), and 1,2,3,4-tetrachlorobenzene (4).The regiochemistry of this reaction is compared with that observed in the photodechlorination of 1 in a micellar solution of hexadecyltrimethylammonium bromide (CTAB) with occupancy numbers (n) principally /=2.Further comparisons with photodechlorination of 1 in a micellar CTAB solution (n 2) in the presence of triethylamine, as well as photodechlorination in CH3CN in the presence of triethylamine, were used to characterize unencumbered radical anions.The regiochemistries observed in photolytic dehalogenations of 1, 2, 1,2,4-trichlorobenzene, and pentafluorobenzene in the presence of triethylamine are in good agreement with those realized in the radical anion fragmentations induced by electron transfer from LiDBB.
- Freeman, P. K.,Ramnath, N.
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- Electroreduction of polychlorobenzenes using either lead or copper electrodes
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Polychlorobenzenes can be reduced electrolytically to dichlorobenzenes by using either lead or copper as the electrodes in a MeOH/THF solution. Among the resultants of dichlorobenzenes, 1,4-dichlorobenzene is a major product that might be due to a low enthalpy of formation. A chlorine atom situated at the ortho position of another chlorine atom in the benzene ring is removed prior to others. However, the sequence of reactivities of the polychlorobenzenes for electroreducing by lead electrodes in this study is as follows: 1,2,3,4-C 6H2Cl4 > 1,3,5-C6H 3Cl3 > C6HCl5 - 1,2,4,5-C 6H2Cl4 > 1,2,3,5-C6H 2Cl4 - 1,2,3-C6H3Cl3 > 1,2,4-C6H3Cl3 > C6Cl 6.
- Lin, Shaw-Tao,Chao, Richard Yung-Ho,Lin, Sun-Che,Lin, Shu-Fan
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- Novel catalysts for dechlorination of polychlorinated biphenyls (PCBs) and other chlorinated aromatics
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Diiron complexes of fluorene and fluorene* (1,2,3,4,5,6,7,8,9- nonamethylfluorene) have been found to be catalysts for the dechlorination of chlorinated aromatics, such as PCBs. The Royal Society of Chemistry.
- Fletcher, Andrew E. D.,Moss, James,Cowley, Andrew R.,O'Hare, Dermot
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- KINETIC STUDY ON THE OXYCHLORINATION OF BENZENE.
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Gas-phase benzene oxychlorination was carried out over a CuCl//2-CeCl//3/Al//2O//3 catalyst. A kinetic model is proposed which permits us to obtain a rate equation capable of reproducing experimental results. The presence of cerium in the catalyst increases the reaction rate and maintains the conversion level for a long time. It seems that this element facilitates copper reoxidation by making the total rate independent of the partial pressure of oxygen and stabilizes the active phase of the catalyst.
- Blanco,Avila,Melo
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- Rate of Reaction of Phenyl Radicals with Oxygen in Solution and in the Gas Phase
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The rate constant for the title reaction, k1, is 3.8 X 109 M-1 s-1 in water at 298 K and is >/= 108 M-1 s-1 in the gas phase at 603 K.It is concluded that two reports that this reaction is very slow in the gas phase, k1 >/= 1.2 X 104 and ca.2.3 X 106 M-1 s-1, are in error.
- Sommeling, Paul M.,Mulder, Peter,Louw, Robert,Avila, David V.,Lusztyk, Janusz,Ingold, K. U.
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- Reactions of 2,4,6-trichlorophenol on model fly ash: Oxidation to CO and CO2, condensation to PCDD/F and conversion into related compounds
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Thermal treatment of 2,4,6-trichlorophenol on a magnesium silicate-based model fly ash in the temperature range between 250°C and 400°C leads predominantly to carbon monoxide and carbon dioxide. The fraction of 2,4,6-trichlorophenol which is oxidized to CO and CO2 increases from 3% at 250°C to 75% at 400°C. Further products are polychlorinated benzenes, dibenzo-p-dioxins, dibenzofurans and phenols. The homologue and isomer patterns of the chlorobenzenes suggest chlorination in the ipso-position of the trichlorophenol. The formation of PCDD from 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol on municipal solid waste incinerator fly ashes and model fly ash were compared and the reaction order calculated.
- Hell,Stieglitz,Altwicker,Addink,Will
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- Simultaneous Dehalogenation of Polychloroarenes and Chlorination of HSiEt3 Catalyzed by Complexes of the Groups 8 and 9
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The catalytic activity of the complexes FeCl2(PPh3)2, RuHCl (PPh3)3, RuH2(CO)(PPh3)3, RuHCl(CO)(AsPh3)3, RuHCl(CO) (PiPr3)
- Diaz, Julia,Esteruelas, Miguel A.,Herrero, Juana,Moralejo, Luisa,Olivan, Montserrat
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- Electrochemical reductive dehalogenation of chlorobenzenes
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Electrochemical dechlorination of 1,2,3,5-tetrachlorobenzene in methanol and chlorobenzene in dimethylsulfoxide with tetraalkylammonium salts as supporting electrolytes was carried out.The extent of dechlorination depends significantly on the electrode composition. - Key words: electrochemical dechlorination, cathodic materials, polychlorobenzenes.
- Plekhanov, V. P.,Tsyganok, A. I.,Kulikov, S. M.
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- Photochemical Rearrangements of o-and m-Dichlorobenzene Cation to p-Dichlorobenzene Cation in Solid Argon
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Matrix photoionization experiments with o- and m-dichlorobenzene and 1,2,4-trichlorobenzene produced and isolated for spectroscopic study not only radical cations of the precursor compound but also rearranged cation products.It is postulated that a bridged chloronium ions is formed upon excitation to the lone pair hole state which serves as an intermediate in rearrangements among the excited-state di- and trichlorobenzene cation isomers.The chlorine lone pair hole excited state facilitates a "chloronium ion walk" around the aromatic ring.
- Friedman, Ronald S.,Andrews, Lester
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- MFI-type zeolite nanosheets for gas-phase aromatics chlorination: A strategy to overcome mass transfer limitations
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The continuous gas-solid (environmentally-friendly) chlorination of deactivated arenes using trichloroisocyanuric acid (TCCA, C3N 3O3Cl3) as a chlorination agent was chosen to compare the catalytic performances of various MFI-type catalysts in a reaction demanding a strong acidity. Mass transfer limitations were also evaluated by reacting either chloro- or nitrobenzene through a ZSM-5 zeolite porous network having different crystal sizes and morphologies. Whereas, the reaction rate was completely controlled by internal diffusion in 10-15 μm-sized big ZSM-5 zeolite crystals (Weisz modulus, big crystals ~ 10), the impact of internal diffusion could be ruled out for ZSM-5 nanocrystals (200-400 nm) and in stacked ZSM-5 nanosheets (thickness 2 nm). Based on reactivity differences in arene halogenation between the two nano-sized ZSM-5 zeolites, we were able to estimate the quantity of mild acidic silanol groups in ZSM-5 nanosheets to roughly 1/3 of the total amount of Brnsted acid sites.
- Boltz, Marilyne,Losch, Pit,Louis, Benoit,Rioland, Guillaume,Tzanis, Lydie,Daou, T. Jean
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- Highly selective photochemical and thermal chlorination of benzene by Cl2 in NaZSM-5
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Loading of zeolite NaZSM-5 with benzene and chlorine from the gas phase at -100°C resulted in spontaneous reaction to form chlorobenzene and 1,4-dichlorobenzene as the sole products. Thermal reaction at elevated temperature (up to 0°C) accelerates the rates toward these products and yields, in addition, some 1,3-dichlorobenzene and a small (2 in the zeolite with green or blue light produced 1,2,4-trichlorobenzene as the only product at high conversion. Such selectivities of benzene chlorination by elemental chlorine are much higher than obtained currently by traditional methods. The sharp increase of the reaction rate in NaZSM-5 compared to that in homogeneous liquid or gas phase and the effect of electronic excitation by visible light are attributed to an enhanced electrophilic character of the chlorine molecule.
- Kirkby, Scott J.,Frei, Heinz
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- Highly active polymer anchored palladium catalyst for the hydrodehalogenation of organic halides under mild conditions
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Palladium anchored on poly(N-vinyl-2-pyrrolidone) (PVP-PdCl2) exhibits very high catalytic activity for the hydrodehalogenation of organic halides under atmospheric pressure in the presence of a base.
- Zhang, Yiping,Liao, Shijian,Xu, Yun
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- Kinetic study of the hydrogenolysis of polychlorobenzenes over a Pd/C catalyst in an alkaline aqueous-n-hexane system
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The kinetics of the hydrogenolysis of chlorobenzene, dichlorobenzenes and some trichlorobenzenes over a 10% Pd/C catalyst was studied using a multiphase system. The reactions were carried out in a batch reactor with an aqueous NaOH/n-hexane solution of chloroaromatic compound as the liquid phase. Benzene was the final product of the hydrogenolysis of all the compounds studied. Hydrogenolysis was more effective in the presence of in situ generated hydrogen than gaseous hydrogen. The initial reaction rates and TOFs of dichlorobenzenes and trichlorobenzenes were slightly lower than those of chlorobenzene. The position of the chlorine atoms in trichlorobenzenes affects the kinetics of the removal of the first chlorine from these molecules. The differences in chlorine reactivity were explained by the inductive and steric effects induced by the benzene-Cl bonds.
- Anusiewicz, Iwona,Janiak, Tadeusz,Okal, Janina
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- A new advanced method for heterogeneous catalysed dechlorination of 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes in hydrocarbon solvent
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A new advanced method for dechlorination of 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes in organic solvent catalysed by palladium on carbon support and solid hydrazine hydrochloride yields benzene in short reaction times. The catalyst system can be efficiently reused for several cycles. Ultrasound radiation of the heterogeneous catalyst reaction increases remarkably the rate of dechlorination.
- Rodríguez, J. Gonzalo,Lafuente, Antonio
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- Facile Synthesis of a Fully Fused, Three-Dimensional ?-Conjugated Archimedean Cage with Magnetically Shielded Cavity
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The synthesis of molecular cages consisting of fully fused, ?-conjugated rings is rare due to synthetic challenges including preorganization, large strain, and poor solubility. Herein, we report such an example in which a tris-2-aminobenzophenone precursor undergoes acid-mediated self-condensation to form a truncated tetrahedron, one of the 13 Archimedean solids. Formation of eight-membered [1,5]diazocine rings provides preorganization and releases the strain while still maintains weak ?-conjugation of the backbone. Thorough characterizations were performed by X-ray, NMR, and UV-vis analysis, assisted by theoretical calculations. The cage exhibits a rigid backbone structure with a well-defined cavity that confines a magnetically shielded environment. The solvent molecule, o-dichlorobenzene, is precisely encapsulated in the cavity at a 1:1 ratio with multiple ?···?, C-H···?, and halogen···πinteractions with the cage skeleton, implying its template effect for the cage closing reaction. Our synthetic strategy opens the opportunity to access more complex, fully fused, three-dimensional ?-conjugated cages.
- Han, Yi,Jiao, Tianyu,Li, Zhengtao,Ni, Yong,Wu, Jishan,Wu, Shaofei,Zhang, Qiuyu,Zhu, Jun
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supporting information
p. 14314 - 14321
(2021/09/13)
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- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
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An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.
- Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
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p. 18040 - 18049
(2021/05/29)
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- Amplification of Trichloroisocyanuric Acid (TCCA) Reactivity for Chlorination of Arenes and Heteroarenes via Catalytic Organic Dye Activation
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Heteroarenes and arenes that contain electron-withdrawing groups are chlorinated in good to excellent yields (scalable to gram scale) using trichloroisocyanuric acid (TCCA) and catalytic Brilliant Green (BG). Visible-light activation of BG serves to amplify the electrophilic nature of TCCA, providing a mild alternative approach to acid-promoted chlorination of deactivated (hetero)aromatic substrates. The utility of the TCCA/BG system is demonstrated through comparison to other chlorinating reagents and by the chlorination of pharmaceuticals including caffeine, lidocaine, and phenazone.
- Rogers, David A.,Bensalah, Adam T.,Espinosa, Alvaro Tomas,Hoerr, John L.,Refai, Fares H.,Pitzel, Amy K.,Alvarado, Juan J.,Lamar, Angus A.
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supporting information
p. 4229 - 4233
(2019/06/17)
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- Direct Transformation of Arylamines to Aryl Halides via Sodium Nitrite and N-Halosuccinimide
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A one-pot universal approach for transforming arylamines to aryl halides via reaction with sodium nitrite (NaNO2) and N-halosuccinimide (NXS) in DMF at room temperature under metal- and acid-free condition is described. This new protocol that is complementary to the Sandmeyer reaction, is suggested to involve the in situ generation of nitryl halide induce nitrosylation of aryl amine to form the diazo intermediate which is halogenated to furnish the aryl halide.
- Mukhopadhyay, Sushobhan,Batra, Sanjay
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supporting information
p. 14622 - 14626
(2018/09/21)
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- Selective Hydrogenations and Dechlorinations in Water Mediated by Anionic Surfactant-Stabilized Pd Nanoparticles
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We report a facile, inexpensive, and green method for the preparation of Pd nanoparticles in aqueous medium stabilized by anionic sulfonated surfactants sodium 1-dodecanesulfonate 1a, sodium dodecylbenzenesulfonate 1b, dioctyl sulfosuccinate sodium salt 1c, and poly(ethylene glycol) 4-nonylphenyl-3-sulfopropyl ether potassium salt 1d simply obtained by stirring aqueous solutions of Pd(OAc)2 with the commercial anionic surfactants further treated under hydrogen atmosphere for variable amounts of time. The aqueous Pd nanoparticle solutions were tested in the selective hydrogenation reactions of aryl-alcohols, -aldehydes, and -ketones, leading to complete conversion to the deoxygenated products even in the absence of strong Br?nsted acids in the reduction of aromatic aldehydes and ketones, in the controlled semihydrogenation of alkynes leading to alkenes, and in the efficient hydrodechlorination of aromatic substrates. In all cases, the micellar media were crucial for stabilizing the metal nanoparticles, dissolving substrates, steering product selectivity, and enabling recycling. What is interesting is also that a benchmark catalyst like Pd/C can often be surpassed in activity and/or selectivity in the reactions tested by simply switching to the appropriate commercially available surfactant, thereby providing an easy to use, flexible, and practical catalytic system capable of efficiently addressing a variety of synthetically significant hydrogenation reactions.
- La Sorella, Giorgio,Sperni, Laura,Canton, Patrizia,Coletti, Lisa,Fabris, Fabrizio,Strukul, Giorgio,Scarso, Alessandro
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supporting information
p. 7438 - 7446
(2018/05/29)
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- Dimethyl sulfoxide-accelerated reductive deamination of aromatic amines with t-BuONO in tetrahydrofuran
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An efficient method for the conversion of aryl amines into arenes by a one-pot reductive deamination has been achieved. It was found the reductive deamination using t-BuONO in tetrahydrofuran could be accelerated by dimethyl sulfoxide and provided the deamination products with good yields under mild conditions. A plausible mechanism is discussed.
- Fang, Lu,Qi, Liang,Ye, Longfei,Pan, Zhentao,Luo, Wenjun,Ling, Fei,Zhong, Weihui
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p. 579 - 583
(2018/11/27)
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- A method for preparing a chlorobenzene (by machine translation)
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The invention benzene, chlorine is the raw material synthetic a chlorobenzene, metal sulfide as catalyst improves the reaction yield, the reaction temperature is 20 - 60 °C, benzene catalyst levels of 0.5% (Wt), reaction time 40 - 65min, the chlorobenzene the yield of 80%, benzene conversion reaches 90% or more. (by machine translation)
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Paragraph 0016; 0017; 0018; 0019; 0020; 0021
(2017/05/13)
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- Method for preparing mixed dichlorobenzene through batch method
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The invention relates to a method for preparing mixed dichlorobenzene through a batch method. According to the present invention, benzene and chlorine gas are adopted as raw materials to synthesize dichlorobenzene, a metal sulfide is adopted as a catalyst to improve the reaction yield, the reaction temperature is 30-60 DEG C, the catalyst use amount is 0.5% (Wt) of benzene, the reaction time is 60-120 min, the dichlorobenzene yield achieves 93%, the m-dichlorobenzene yield is less than 1%, and the polychlorobenzene yield is less than 1%.
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Paragraph 0015; 0016; 0017; 0019
(2017/07/22)
-
- PROCESS FOR THE PREPARATION OF ORGANIC HALIDES
-
The present invention provides a halo-de-carboxylation process for the preparation of organic chlorides, organic bromides and mixtures thereof, from their corresponding carboxylic acids, using a chlorinating agent selected from trichloroisocyanuric acid (TCCA), dichloroisocyanuric acid (DCCA), or combination thereof, and a brominating agent.
- -
-
Paragraph 00146
(2017/08/01)
-
- Generation of VBr? VBi? VO?? defect clusters for 1O2 production for molecular oxygen activation in photocatalysis
-
Defect engineering on a semiconductor surface can provide coordinatively unsaturated sites for molecular oxygen activation in photocatalysis. In this work, we demonstrated that the vacancy type was key to modulate the molecular oxygen activation process on BiOBr nanosheets. By regulating the reaction time, an oxygen vacancy (VO??), a double atom defect cluster (VBi? VO??) and triple atom clusters (VBi? VO?? VBi? and VBr? VBi? VO??) were accordingly generated on the surface, subsurface and bulk of BiOBr. More importantly, the newly-discovered VBr? VBi? VO?? defect cluster was highly related to the singlet oxygen (1O2) production ability of BiOBr. Meanwhile, the excellent photocatalytic selective oxidation reactions were successfully realized over BiOBr with the VBr? VBi? VO?? defect cluster. In addition, time-dependent defect cluster generation and the associated molecular oxygen activation were discussed.
- Ding, Jie,Dai, Zan,Tian, Fan,Zhou, Bo,Zhao, Bin,Zhao, Huiping,Chen, Zhiquan,Liu, Yunling,Chen, Rong
-
supporting information
p. 23453 - 23459
(2017/11/30)
-
- Dicamba preparation process
-
The invention belongs to the technical field of herbicide dicamba preparation and relates to a dicamba preparation process. The dicamba preparation process includes steps: taking benzene as a raw material to generate 1,2,4-trichlorobenzene through directional chlorination, catalysis, re-chlorination and rectification; hydrolyzing the 1,2,4-trichlorobenzene to generate a mixture of 2,5-dichlorophenol and 2,4-dichlorophenol, and separating and purifying to obtain 2,5-dichlorophenol; using the 2,5-dichlorophenol to prepare 3,6-dichlorosalicylic acid; subjecting the 3,6-dichlorosalicylic acid to methylation, saponification, acidification and the like to obtain dicamba. By optimization of technical steps and parameters, the whole dicamba preparation process has advantages of simplicity, low cost, high yield, high selectivity, remarkable reduction of wastewater and increase of equipment utilization rate.
- -
-
Paragraph 0051; 0052; 0053
(2017/04/03)
-
- When benzene chlorination preparation chlorobenzene, O-dichlorobenzene santochlor and method
-
The invention discloses a method for preparing chlorobenzene, p-dichlorobenzene and o-dichlorobenzene in benzene chlorination, and relates to a preparation method of chemical raw materials. The method comprises the following steps: continuously introducing dry benzene and chlorine with a high activity and high p-dichlorobenzene selectivity catalyst into an outer circulation reactor, wherein the benzene and chlorine need sufficient retaining time, reacting at a set temperature to prepare p-dichlorobenzene, obtain o-dichlorobenzene at the same time and co-produce chlorobenzene, preparing dichlorobenzene by using the outer circulation reactor and taking the benzene and the chlorine as raw materials and metal sulfide as a catalyst, at the same time co-producing chlorobenzene, forming circulation of the materials through the introduced nitrogen and generated hydrogen chloride as power so as to obtain good stirring for prompting mixing, diffusion, heat conduction and mass transfer of the reactants. The method is rapid in reaction speed, high in capacity, large in ratio of p-dichlorobenzene and o-dichlorobenzene, free of polychlorobenzene byproduct, and high in flexibility and operation flexibility as the ratio of the chlorobenzene to the dichlorobenzene in a product can be adjusted according to demands.
- -
-
Paragraph 0033-0035
(2017/04/12)
-
- Eco-compatible zeolite-catalysed continuous halogenation of aromatics
-
A completely eco-compatible halogenation reaction of arenes has been developed allowing high conversions (>95%) of iodobenzene with nearly 100 kg iodobenzene converted per kgcat in one day. Several solid acids, zeolites being the most promising, have been successfully tested in the chlorination reaction of iodobenzene by using trichloroisocyanuric acid (TCCA), a green chlorination agent. H-?BEA zeolites were found to be the most active catalysts for this model halogenation reaction. A strong structure-activity relationship could be established by thorough characterisation (SEM, BET, XRD, FTIR) of various synthetic zeolites. Indeed, nano-sized ?BEA zeolites and more specifically nanosponge-like ?BEA crystals exhibited the highest catalytic performance with a conversion up to 100% and a selectivity toward monochlorinated products up to 98%. Finally, the gained knowledge was applied to set-up an eco-compatible continuous flow halogenation process of different aromatics catalysed by H-?BEA zeolites.
- Losch,Kolb,Astafan,Daou,Pinard,Pale,Louis
-
p. 4714 - 4724
(2016/09/04)
-
- Facile Separation of Regioisomeric Compounds by a Heteronuclear Organometallic Capsule
-
Owing to the often-similar physical and chemical properties of structural isomers of organic molecules, large efforts have been made to develop efficient strategies to isolate specific isomers. However, facile separation of regioisomeric compounds remains difficult. Here we demonstrate a universal organometallic capsule in which two silver centers are rigidly separated from each other by two tetranuclear [Rh4] pyramidal frustums, which selectively encapsulate a specific isomer from mixtures. Not only is the present heterometallic capsule suitable as a host for the encapsulation of a series of aromatic compounds, but also the receptor shows widely differing specificity for the various isomers. Direct experimental evidence is provided for the selective encapsulation of a series of para (p)-disubstituted benzene derivatives, such as p-xylene, p-dichlorobenzene, p-dibromobenzene, and p-diiodobenzene. The size and shape matching, as well as the Ag-π interactions, are the main forces governing the extent of molecular recognition. The encapsulated guest p-xylene can be released by using the solid-liquid solvent washing strategy, and the other guest molecules are easily liberated by using light stimulus.
- Zhang, Wen-Ying,Lin, Yue-Jian,Han, Ying-Feng,Jin, Guo-Xin
-
p. 10700 - 10707
(2016/09/04)
-
- A method for the synthesis of 2, 5 - dichlorophenol (by machine translation)
-
The invention relates to a 2, 5?Dichiorophenol synthetic method, which belongs to the technical field of the synthesis of the key intermediate chamber. The invention is composed of a pure chlorization generated 1, 2, 4?Trichlorobenzene and santochlor is easy to separate, thereby avoiding the difficulties caused by the separating of the high production cost and low production efficiency; because the 1, 2, 4?Trichlorobenzene and to two chiorophenoxy can be obtained respectively 2, 5?Dichiorophenol, utilization rate of raw materials is high, thereby avoiding the waste of the by-product, so that the production cost is greatly reduced. In addition, the two paradichlorbenzene through two different method to obtain 2, 5?Dichiorophenol. The synthesis technique of this invention is simple, the production cost is low, the utilization rate of raw materials is high, and the craft there are few by-products, less generation of three wastes, is more suitable for large-scale industrial production. (by machine translation)
- -
-
Paragraph 0064
(2016/10/09)
-
- Production of paradichlorobenzene
-
A process for producing paradichlorobenzene with a practical apparatus is provided in which the desired compound is obtained in a high yield and the apparatus can be stably operated. The process comprises chlorinating benzene and/or monochlorobenzene as a starting material with chlorine gas to produce paradichlorobenzene, wherein the starting material is introduced into reactors arranged in multiple stages and packed with a catalyst comprising alumina as a main component. Chlorine gas is supplied, in parallel, to the reactors. The starting material and chlorine gas are supplied to the first-stage reactor, and a reaction product obtained in the preceding stage is supplied to the second-stage reactor. Chlorine gas is supplied, in parallel, to the second-stage and succeeding reactors, and paradichlorobenzene is obtained from a reaction product obtained in the final stage.
- -
-
Paragraph 0046-0049; 0065; 0069-0070
(2016/12/22)
-
- Substd. photoisomerization arom. compd. method
-
Isomerizing substituted aromatic compounds (I), comprises carrying out isomerization in the presence of a salt melt, which contains a metal compound (II) and at least one metal compound (III). Isomerizing substituted aromatic compounds of formula (Ar1-R n) (I) or their mixtures, comprises carrying out isomerization in the presence of a salt melt, which contains a metal compound of formula ([M1][X1] m 1) (II) and at least one metal compound of formula ([M2][X2] m 2) (III). Ar1 : n-valent aryl radical; R : halo, alkyl, fluoroalkyl, aryl, alkyl-aryl or amino; M1 : Al, Ga, In, Cu, Fe, Co or Ni; X1, X2 : halo, preferably Cl or Br; M2, m2 : alkaline earth metal or alkali metal, where M2 is preferably Li, Na, or K; m1 : Al, Ga, In, Fe(III), Co, Ni or Cu(II); and n : >= 2, preferably 2.
- -
-
Paragraph 0062
(2017/01/02)
-
- N2 extrusion and co insertion: A novel palladium-catalyzed carbonylative transformation of aryltriazenes
-
A novel procedure for the replacement of N2 with CO of aryltriazenes has been developed. Aryltriazenes were converted to the corresponding arylamides catalyzed by 1 mol % of PdCl2/P(o-Tol)3 under CO pressure. In this process, aryldiazonium salts were generated in the presence of 40 mol % of MeSO3H. Nitrogen was released from the substrates and CO formally inserted. Aryl bromides, iodides, alkynes, and free hydroxyl groups can be tolerated in this transformation.
- Li, Wanfang,Wu, Xiao-Feng
-
p. 1910 - 1913
(2015/04/27)
-
- PROCESSES FOR THE DIAZOTIZATION OF 2,5-DICHLOROANILINES
-
The present disclosure relates, in general, to processes for converting 2,5- dichloroaniline compounds to the corresponding 2,5-dichlorobenzenediazonium compounds, and further relates to processes for the preparation of 2,5-dichloro- phenol which is a key intermediate used in the manufacture of dicamba.
- -
-
Paragraph 121-122
(2015/07/07)
-
- Glycinatocopper(II) complex as an efficient heterogeneous catalyst for aromatic Finkelstein reaction of aryl and heteroaryl bromides to chlorides
-
Glycinatocopper(II) complex 1, readily synthesized from copper chloride and glycine was characterized by various techniques including FTIR, XRD, TGA and SEM analysis. The as-synthesized copper complex was found to be a simple and efficient catalyst for the synthesis of aryl and heteroaryl chlorides via aromatic Finkelstein reaction of aryl and heteroaryl bromides in high to excellent yields. The developed glycinatocopper(II) catalyst could easily be recovered from the reaction mixture and reused successfully for several runs without any loss in catalytic efficiency. The developed methodology represents the first example of the use of heterogeneous catalyst for the synthesis of aryl and heteroaryl chlorides via aromatic Finkelstein reaction.
- Verma, Sanny,Saran, Sandeep,Jain, Suman L.
-
p. 178 - 183
(2014/02/14)
-
- Iron(III)-mediated photocatalytic selective substitution of aryl bromine by chlorine with high chloride utilization efficiency
-
An iron(III)-mediated photocatalytic method for the conversion of aryl, heteroaryl and polycyclic aromatic bromides to the corresponding chlorides with high selectivity has been achieved successfully. The mild reaction conditions and high chloride utilization efficiency promise a bright future for chlorination reactions. The Royal Society of Chemistry 2014.
- Wang, Ying,Li, Lina,Ji, Hongwei,Ma, Wanhong,Chen, Chuncheng,Zhao, Jincai
-
supporting information
p. 2344 - 2346
(2014/03/21)
-
- Anionarylation of acrylic and methacrylic acids derivatives with p- and m-phenylenebisdiazonium tetrafluoroborates
-
Chloro-, bromo- and thiocyanatoarylation of amides and nitriles of acrylic and methacrylic acids with bisdiazonium salts based on m- and p-phenylenediamines have been studied. 3,3'-[1,4(3)-phenylene]bis[2-halopropanamides(nitriles)] and 2-thiocyanato-(2-m
- Baranovskii,Yatsyuk,Grishchuk
-
p. 1505 - 1509
(2015/02/19)
-
- Dechlorination of hexachlorobenzene by nano zero-valent iron/activated carbon composite: Iron loading, kinetics and pathway
-
Nano zero-valent iron (nZVI) and activated carbon composites were synthesized and employed to remove hexachlorobenzene (HCB). Methods of impregnation and adsorption were employed to firstly load iron salt onto activated carbon, and thus loaded iron was then reduced to form zero valent iron. Results indicate that the method of iron loading significantly impacted the amount of iron and HCB dechlorination. In general, nZVI/activated carbon composite synthesized using an adsorption method showed considerably higher removal efficiency and dechlorination capability. More than 80% of the HCB was dechlorinated after 48 h. The dechlorination of HCB followed a stepwise pathway: HCB (hexachlorobenzene) → PCB (pentachlorobenzene) → 1,2,4,5 TeCB (tetrachlorobenzene) → TriCB (trichlorobenzene) → 1,4 DCB (dichlorobenzene) → MCB (monochlorobenzene). Compared with activated carbon or nZVI, nZVI/activated carbon composite showed much higher HCB removal. Analysis of mass partition on solid and aqueous phases indicates that most of the HCB and its dechlorination intermediates were retained on solids probably due to the strong adsorption on activated carbon. In summary, activated carbon performs three important functions: it alleviated the limitation of nZVI agglomeration, contributed to HCB removal due to its own adsorption capability and increased the resistance of nZVI against pH change. This journal is
- Chen, Wei-Fang,Pan, Ling,Chen, Li-Fang,Wang, Qiong,Yan, Chang-Cheng
-
p. 46689 - 46696
(2014/12/11)
-
- Halogen exchange via a halogenation of diaryliodonium salts with cuprous halide
-
An efficient halogenation reaction has been developed with diaryliodonium salts and cuprous halides. Various diaryliodonium salts 1 could perform the reaction with readily available CuBr or CuCl in CH3CN at 80°C, assembling bromoarenes or chloroarenes in up to 92% yields. This provides us a method for the transformation from iodoarenes to other haloarenes.
- Li, Jian,Liu, Li,Ding, Dong,Sun, Jiang-Tao
-
p. 541 - 548
(2014/01/06)
-
- Efficient oxidative chlorination of aromatics on saturated sodium chloride solution
-
An efficient metal-free system using saturated aqueous sodium chloride/aqueous ammonium chloride solution as chlorine source and potassium persulfate as a cheap oxidant for the chlorination of various aromatic compounds including deactivated ones has been developed that proceeds without any acid additive in an excellent regioselective manner. The easy-to-handle aqueous solution/acetonitrile biphasic system as solvent and no need for precautionary measures make this process very practical. Copyright
- Gu, Liuqun,Lu, Ting,Zhang, Mingyun,Tou, Lijuan,Zhang, Yugen
-
supporting information
p. 1077 - 1082
(2013/05/21)
-
- Electrophilic chlorination of arenes with trichloroisocyanuric acid over acid zeolites
-
Trichloroisocyanuric acid (TCCA) reacts with arenes and its reactivity is highly affected by the acid strength of the reaction medium. Deactivated arenes are efficiently chlorinated by TCCA in solid acids. Our experimental results, along with DFT calculations show that chlorination using solid acid catalysis is feasible, thus leading to possible replacement of strong liquid acids used to promote this superelectrophilic reaction. We have tested several solid acids, showing the synergic need for acid strength and pore size for promoting the reaction.
- Mendon?a, Gabriela F.,Bastos, Alexander R.,Boltz, Marilyne,Louis, Beno?t,Pale, Patrick,Esteves, Pierre M.,De Mattos, Marcio C.S.
-
-
- Halogenation and DNA cleavage via thermally stable arenediazonium camphorsulfonate salts
-
A series of stable arenediazonium camphorsulfonate salts (2a-2j) were synthesized by simple diazotization of several aromatic amines in the presence of sodium nitrite and camphorsulfonic acid. All the new arenediazonium camphorsulfonates, which were characterized by multinuclear (1H and 13C) NMR, IR, DSC, and X-ray diffraction analysis (2e and 2f) provide unambiguous proof for the molecular structures of 2e and 2f. The efficient application of these salts in halogenation reactions was studied in solvent and solvent-free conditions and the DNA cleavage activity was also assessed. These arenediazonium camphorsulfonate salts are noticed as efficient DNA cleaving agents.
- Vajpayee, Vaishali,Moon, Mi Eun,Lee, Sunmi,Ravikumar, Sambandam,Kim, Hyunuk,Ahn, Byungchan,Choi, Seoyoon,Hong, Soon Ho,Chi, Ki-Whan
-
p. 3511 - 3517
(2013/04/23)
-
- Copper-catalyzed conversion of aryl and heteroaryl bromides into the corresponding chlorides
-
An efficient method for the synthesis of aryl and heteroaryl chlorides is described. The reactions of aryl and heteroaryl bromides with tetramethylammonium chloride proceeded smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding chlorides in satisfactory to excellent yields.
- Feng, Xiujuan,Qu, Yiping,Han, Yanlei,Yu, Xiaoqiang,Bao, Ming,Yamamoto, Yoshinori
-
supporting information
p. 9468 - 9470
(2012/10/29)
-
- Cu(I)/cu(II)/TMEDA, new effective available catalyst of sandmeyer reaction
-
The system Cu(I)/Cu(II)/N,N,N',N'-tetramethylethylenediamine is a highly effi cient and accessible catalyst of Sandmeyer reaction. The reaction of aryldiazonium salts with chlorides, bromides cyanides, and thiocyanates of alkaline metals in the presence of this catalytic system leads to the formation of the corresponding aryl halides, nitriles, and thiocyanates in high yields.
- Sigeev, A. S.,Beletskaya, I. P.,Petrovskii, P. V.,Peregudov, A. S.
-
p. 1055 - 1058,4
(2020/10/15)
-
- INDUSTRIAL METHODS FOR PRODUCING ARYLSULFUR PENTAFLUORIDES
-
Industrial methods for producing arylsulfur pentafluorides are disclosed. Methods include reacting arylsulfur halotetrafluoride with hydrogen fluoride in the absence or presence of one or more additives selected from a group of fluoride salts, non-fluoride salts, and unsaturated organic compounds to form arylsulfur pentafluorides.
- -
-
Page/Page column 25; 29-30; 31-33
(2012/09/10)
-
- Trichloroisocyanuric acid in 98% sulfuric acid: A superelectrophilic medium for chlorination of deactivated arenes
-
Trichloroisocyanuric acid (TCCA) reacts with arenes and its reactivity is highly affected by the acid strength of the reaction medium. Deactivated arenes are efficiently chlorinated by TCCA in H2SO4. Our results, along with DFT calculations and 13C NMR spectrometry suggest the formation of a monoprotonated TCCA superelectrophile as the reactive species that can efficiently transfer electrophilic Cl+ to even very weak nucleophiles, such as m-dinitrobenzene.
- Mendo?a, Gabriela Fonseca,Senra, M?nica Rufino,Esteves, Pierre M.,De Mattos, Marcio C.S.
-
experimental part
p. 176 - 181
(2012/04/04)
-
- Base-promoted selective aryl C-Cl cleavage by iridium(III) porphyrins via a metalloradical ipso addition-elimination mechanism
-
Base-promoted aryl carbon-chlorine bond (Ar-Cl) cleavage by iridium(III) porphyrin carbonyl chloride (IrIII(ttp)(CO)Cl; ttp = 5,10,15,20-tetrakis(p-tolyl)porphyrinato dianion) was achieved in the presence of K2CO3 to give iridium(III) porphyrin aryls (Ir III(ttp)Ar). Mechanistic studies revealed that K2CO 3 promotes the reduction of Ir(ttp)(CO)Cl to give the iridium(II) porphyrin dimer intermediate [IrII(ttp)2. [Ir(ttp) 2 is the source of IrII(ttp) metalloradical, which cleaves Ar-Cl to give Ir(ttp)Ar and a chlorine radical (Cl?) via radical ipso substitution in an addition-elimination pathway. Cl ? reacts with [Ir(ttp)2 to yield Ir(ttp)Cl for subsequent base-promoted reduction and Ir(ttp) for radical chain propagation. Additionally, the base-promoted Ar-Cl cleavage of chlorobenzene (PhCl) by Ir(ttp)(CO)Cl gives both Ir(ttp)Ph and 1,4-bis-iridium(III)-porphyrin benzene, IrIII(ttp)(p-C6H4)IrIII(ttp). The reactive Cl? can simultaneously react with PhCl via homolytic aromatic substitution to give 1,4-dichlorobenzene, which further undergoes double Ar-Cl cleavage to form Ir(ttp)(p-C6H4)Ir(ttp).
- Cheung, Chi Wai,Chan, Kin Shing
-
experimental part
p. 4999 - 5009
(2011/11/04)
-
- Metal-free chlorodeboronation of organotrifluoroborates
-
A mild and metal-free method for the chlorodeboronation of organotrifluoroborates using trichloroisocyanuric acid (TCICA) was developed. Aryl-, heteroaryl-, alkenyl-, alkynyl-, and alkyltrifluoroborates were converted into the corresponding chlorinated products in good yields. This method proved to be tolerant of a broad range of functional groups.
- Molander, Gary A.,Cavalcanti, Livia N.
-
experimental part
p. 7195 - 7203
(2011/10/13)
-
- PROCESS FOR PRODUCING p-DICHLOROBENZENE
-
To provide a novel process for producing p-dichlorobenzene satisfying both of high selectivity of p-dichlorobenzene and high conversion of chlorine at the same time. A process for continuously producing p-dichlorobenzene, which is a process for producing p-dichlorobenzene by a nuclear chlorination reaction of benzene and/or chlorobenzene with chlorine, in the presence of a Lewis acid catalyst and a phenothiazine analogue compound, said process comprising; employing a reactor having a first supply route for continuously supplying a mixed solution of benzene and/or chlorobenzene and a Lewis acid catalyst to a reactor, a second supply route for continuously supplying a mixed solution of benzene and/or chlorobenzene and a phenothiazine analogue compound to the above reactor, and a third supply route for continuously supplying chlorine to the above reactor; and supplying these raw materials for the reaction by opening the above first supply route and third supply route in random order at the initiation of reaction, and then opening the above second supply route.
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-
Page/Page column 7
(2011/08/08)
-
- A new class of heterogeneous platinum catalysts for the chemoselective hydrogenation of nitroarenes
-
A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel.
- Pandarus, Valerica,Ciriminna, Rosaria,Beland, Francois,Pagliaro, Mario
-
scheme or table
p. 1306 - 1316
(2011/06/25)
-
- Chlorination of various substrates in subcritical carbon tetrachloride
-
Various aliphatic hydrocarbons and the side chains of aromatic hydrocarbons were chlorinated in subcritical carbon tetrachloride. Chlorination of aromatic compounds including 1,4-disubstituted benzenes was investigated. Ketones and sulfones were stable under the employed conditions. Sulfoxides were converted into sulfides in a low to modest yields. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
-
experimental part
p. 2881 - 2888
(2010/06/16)
-
- Chlorination of aromatics with trichloroisocyanuric acid (TCICA) in bronsted-acidic imidazolium ionic liquid [BMIM(SO3H)][OTf]: An economical, green protocol for the synthesis of chloroarenes
-
A survey study on electrophilic chlorination of aromatics with trichloroisocyanuric acid (TCICA) in Bronsted-acidic imidazolium ionic liquid [BMIM(SO3H)][OTf] is reported. The reactions are performed under very mild conditions (at ~50°C) and give good to excellent yields, depending on the substrates. Chemoselectivity for mono- v. dichlorination can be tuned by changing the arene-to-TCICA ratio and the reaction time. The survey study and competitive experiments suggest that triprotonated/protosolvated TCICA is a selective/moderately reactive transfer-chlorination electrophile. Density functional theory was used as guide to obtain further insight into the nature of the chlorination electrophile and the transfer-chlorination step. CSIRO 2007.
- Hubbard, Abigail,Okazaki, Takao,Laali, Kenneth K.
-
p. 923 - 927
(2008/03/17)
-
- Natural kaolinitic clay: A remarkable catalyst for highly regioselective chlorination of arenes with Cl2 or SO2Cl2
-
Natural kaolinitic clay containing transition metals such as Fe and Ti in its lattice has been found to exhibit unusual regioselectivity in the liquid-phase chlorination of arenes with either Cl2 or SO 2Cl2 as the chlorinating agent para-Chlorinated products are predominant for most of the substrates with an exceptional case of ortho-selectivity for the chlorination of aniline.
- Jayachandran,Phukan, Prodeep,Daniel, Thomas,Sudalai
-
p. 972 - 975
(2007/10/03)
-
- Method for separating substances
-
An objective of the present invention is to provide electrophoretic separation methods and devices that enable the various features of a substrate surface that comes in contact with an electrophoresis medium to be controlled. The present invention provides methods for electrophoresing substances, which comprises the steps of: (a) adding a substance to be analyzed to an electrophoresis medium retained in a substrate, whose surface that has come in contact with the electrophoresis medium has been coated with a polymer membrane; and (b) adding electrophoretic pressure to the electrophoresis medium. For example, the use of a plasma-polymerized membrane allows the formation of a membrane with homogeneous quality and thickness on the surface of an arbitrary shape. In addition, desired characteristics can be conferred on the surface through selection of monomeric substances. Protein adsorption onto micro-chips can be effectively prevented as well.
- -
-
-
- METHOD FOR PRODUCING P-DICHLOROBENZENE
-
In a process for preparing p-dichlorobenzene by nuclear chlorination of benzene and/or chlorobenzene as the starting material with chlorine molecules, chlorination is carried out using aluminum chloride in an amount of 0.1 - 3 millimols per mol of the starting material and phenothiazines such as 10H-phenothiazine-10-carboxylic acid phenyl ester in an amount of 0.1 - 0.9 mols per mol of aluminum chloride so as to be a chlorination degree in a range of 1.2 - 2.5, by which p-dichlorobenzene can be obtained in a high para-selectivity and a short reaction time.
- -
-
Page/Page column 5
(2008/06/13)
-
- PROCESS FOR HALOGENATION OF BENZENE AND BENZENE DERIVATIVES
-
In a process of halogenation of benzene or benzene derivatives, di-substituted halobenzene derivatives having para-aromatic compounds or tri-substituted halobenzene derivatives having 1,2,4-substituted aromatic compounds are selectively produced. In halogenation of benzene or benzene derivatives, a fluorine-containing zeolite catalyst such as L-type zeolite, or a zeolite catalyst having the crystal size of at most 100 nm is used. The reaction is preferably effected in the presence of a solvent, and the solvent is preferably a halogenated compound.
- -
-
Page/Page column 20; 21
(2008/06/13)
-
- N-halosuccinimide/BF3-H2O, efficient electrophilic halogenating systems for aromatics
-
N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF3-H2O, allowing the halogenations of deactivated aromatics. Because BF3-H2O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H0 ≈ 12, only slightly lower than that of trifluoromethanesulfonic acid), an efficient new electrophilic reagent combination of NXS/BF3-H2O has been developed. DFT calculations at the B3LYP/6-311++G**//B3LYP/6-31G* level suggest that protonated N-halosuccinimides undergo further protosolvation at higher acidities to reactive superelectrophilic species capable either in the transfer of X+ from the protonated forms of NXS to the aromatic substrate or in forming a highly reactive and solvated X+ which would readily react with the aromatic substrates. Structural aspects of the BF 3-H2O complex have also been investigated.
- Prakash, G. K. Surya,Mathew, Thomas,Hoole, Dushyanthi,Esteves, Pierre M.,Wang, Qi,Rasul, Golam,Olah, George A.
-
p. 15770 - 15776
(2007/10/03)
-
- Catalytic process for regiospecific chlorination of alkanes, alkenes and arenes
-
The present invention provides a process for regiospecific chlorination of an aromatic or aliphatic compound with a chlorine source comprising a metal chloride and other than Cl2and SO2Cl2in presence of hypervalent iodine catalyst and in acidic medium.
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-
Page column 6
(2008/06/13)
-
- Formation and destruction of chlorinated pollutants during sewage sludge incineration
-
The limitations facing land filling and recycling and the planned ban on sea disposal of sludge leads to the expectation that the role of sludge incineration will increase in the future. The expected increase in sludge incineration will also increase scrutiny of the main drawback to sewage sludge incineration-the formation of hazardous air pollutants (HAPs). Despite the extensive body of knowledge available on sewage sludge combustion, very few studies have been conducted on the formation of HAPs during sludge combustion. In this work, the interactions between sewage sludge pyrolysis products and sludge ash were investigated using a dual chamber flow reactor system and a horizontal laboratory scale reactor. The results of this study shows that sludge ash can catalyze oxidation and chlorination of organics. In the absence of HCl in the gas stream, sludge ash acts as an oxidizing catalyst, but in the presence of HCl, sludge ash acts as a chlorination catalyst producing high yields of organochloride compounds.
- Fullana, Andres,Conesa, Juan A.,Font, Rafael,Sidhu, Sukh
-
p. 2953 - 2958
(2007/10/03)
-
- Halogenation of Aromatic Compounds by N-chloro-, N-bromo-, and N-iodosuccinimide
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An efficient and mild method for the halogenation of aromatic compounds using N-chloro-, N-bromo-, and N-iodosuccinimide in the presence of NH 4NO3 or FeCl3 in acetonitrile was developed.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
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p. 932 - 933
(2007/10/03)
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