- Controlled methyl chloride synthesis at mild conditions using ultrasound irradiation
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A new route for the chlorination of methane is described using ultrasound irradiation, which allows for an intrinsically safe process at ambient pressure and temperature. By tuning the gas feed composition methyl chloride yields of up to 19% have been obtained.
- Iersel, Maikel M. van,Schilt, Marcus A. van,Benes, Nieck E.,Keurentjes, Jos T.F.
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- Pressure Dependence of the Rate Constants for the Reactions CH3 + O2 and CH3 + NO from 3 to 10E4 Torr
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A relative rate technique is used to measure the pressure dependence of the rate constants for reaction 1 (CH3 + O2 + M -> CH3O2 + M) and reaction 3 (CH3 + NO + M -> CH3NO + M) relative to reaction 2 (CH3 + Cl2 -> CH3Cl + Cl).The pressure dependence of the rate constant of reaction 3 at 297 K can be represented in the Troe equation by the parameters (k3)0 = (3.5 +/- 0.4)E-30 cm6 molecule-2 s-1, (k3)infinite = (1.68 +/- 0.1)E-11 cm3 molecule-1 s-1, and Fcent = 0.46.The values of k3 are identical to those observed in recent absolute rate measurements at 296 K and 27-600 Torr, verifying that the rate constant chosen for reaction 2, k2 = 3.95E-12 exp(-530/RT), is both pressure independent and correct at 296 K.This value of k2 was used to determine absolute values of k1 from the k1/k2 in N2 diluent for pressures between 3 and 11000 Torr at 297 K, between 20 and 1500 Torr at 370 K, and between 40 and 1500 Torr at 264 K.All data in N2 can be fitted using the following parameters in the Troe equation: (k1)0 = (7.56 +/- 1.1)E-31 (T/300)-3.64+/-1.0 cm6 molecule-2 s-1; (k1)infinite = (1.31 +/- 0.1)E-12 (T/300)1.2+/-0.8 cm3 molecule-1 s-1; Fcent = 0.48 (264 K), 0.46 (297 K), 0.42 (370 K).Error limits include statistical error and the uncertainty in k2.In He, N2, and SF6 diluents the relative third-body efficiencies are 0.56 : 1.0 : 1.52, respectively, assuming that Fcent is independent of diluent.The high-pressure limit in SF6 is identical to that in N2.Rate constant ratios were also measured at 297 K for CD3 + O2 + M -> CD3O2 + M (1D) between 5 and 6000 Torr.Assuming that k2D = k2, the limiting rate constants using Fcent = 0.46 are (k1D)0 = (11.8 +/- 1.6)E-31 cm6 molecule-2 s-1 and (k1D)infinite = (1.38 +/- 0.08)E-12 cm3 molecule-1 s-1.
- Kaiser, E. W.
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- Study of the reaction methyl 4-nitrobenzene-sulfonate + Cl- in mixed hexadecyltrimethyl-ammonium chloride-Triton X-100 micellar solutions
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The reaction methyl 4-nitrobenzenesulfonate + Cl- was studied in hexadecyltrimethylammonium chloride (CTAC) in the absence and presence of 0.1 M NaCl, as well as in mixed CTAC/Triton X-100 (polyoxyethylene(9.5)octylphenyl ether) aqueous micella
- Fernandez, Gaspar,Rodriguez, Amalia,Del Mar Graciani, Maria,Munoz, Maria,Moya, Maria Luisa
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- Methane to Chloromethane by Mechanochemical Activation: A Selective Radical Pathway
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State-of-The-Art processes to directly convert methane into CH3Cl are run under corrosive conditions and typically yield a mixture of chloromethanes requiring subsequent separation. We report a mechanochemical strategy to selectively convert methane to chloromethane under overall benign conditions, employing trichloroisocyanuric acid (TCCA) as a cheap and noncorrosive solid chlorinating agent. TCCA is shown to release active chlorine species upon milling with Lewis acids such as alumina and ceria to functionalize methane at moderate temperatures (4,conv) (g(catalyst) s)-1. Findings were compared to the thermal reaction of methane with TCCA and evidenced that mechanochemical activation permitted significantly lower reaction temperatures (90 vs 200 °C) at a drastically improved CH3Cl selectivity (95% vs 66% at 30% conversion). Considering the characterization of the interaction between TCCA and Lewis acids as well as the in-depth analysis of byproducts, we suggest a plausible reaction mechanism and a possible regeneration of the chlorinating agent.
- Bilke, Marius,Losch, Pit,Vozniuk, Olena,Bodach, Alexander,Schüth, Ferdi
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- Vibrational excitation in products of nucleophilic substitution: The dissociation of metastable X-(CH3Y) in the gas phase
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The relative kinetic energy distributions for the Y- + CH3X nucleophilic substitution products from dissociation of metastable X-(CH3Y) (X = Cl, Br; Y = Br, I) have been analyzed by means of ion kinetic energy spectroscopy, and the results modeled using statistical phase space theory. Comparison of the experimental distributions with the theoretical distributions predicted for statistical partitioning of the available energy reveals that the substitution products are translationally cold. The theoretically calculated distributions can be made to agree with experiment if most of the energy released in the dissociation is assumed to be unavailable for randomization, such that it cannot partition to relative translation. This unavailable energy must correspond to internal energy, most likely vibrational excitation, in the CH3X products. These results are consistent with recent theoretical predictions of non-RRKM dynamics in gas-phase SN2 reactions.
- Graul, Susan T.,Bowers, Michael T.
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- Rate constants for the gas phase reaction of chloride ion with methyl bromide over the pressure range 300 to 1100 torr
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Rate constants for the reaction of chloride ion with methyl bromide have been determined over a range of buffer gas pressures from 300 to 1100 Torr at 125 °C by ion mobility spectrometry (IMS). The rate constants were found to increase slightly with increased pressure over this range and also increased slightly with a change from nitrogen to methane buffer gas. Parallel measurements for the reaction of chloride ion with n-butyl bromide indicated no dependence of the observed rate constants on changes in the pressure or identity of the buffer gas, as expected. The present measurements indicate that the high-pressure limit (HPL) of kinetic behavior is not achieved for the Cl-/CH3Br reaction system by use of buffer gases in the near-atmospheric pressure range and are consistent with a recent suggestion by Seeley et al. that this reaction should occur with near-collision frequency in its high-pressure limit.
- Sahlstrom,Knighton,Grimsrud
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- Low-temperature combustion of chlorinated hydrocarbons over CeO 2/H-ZSM5 catalysts
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The performance of various CeO2/H-ZSM5 catalysts was evaluated for the oxidation of one of the most common chlorinated pollutants found in waste streams, namely 1,2-dichloroethane. The supported samples with varying CeO2 loading (6-50 wt.%) were prepared by impregnation and subsequently calcined at 550 °C. Structural, morphological and physico-chemical changes caused by the CeO2 addition were analysed by X-ray diffraction, transmission electronic microscopy, N2- physisorption, temperature-programmed desorption of ammonia and temperature-programmed reduction with hydrogen. The enhancement of the catalytic behaviour of the resulting samples with respect to plain H-ZSM5 could be accounted for on the basis of the synergetic role played by oxygen mobility and acid sites. Hence, an optimum cerium loading of 11 wt.% was found with a T 50 value around 210 °C. At 350 °C, where conversion of the chlorinated feed is about 99%, the major oxidation products were carbon oxides and hydrogen chloride with a reduced presence of chlorinated by-products and molecular chlorine. A relatively good catalytic stability was noticed during 80 h time on line.
- De Rivas, Beatriz,Sampedro, Carmen,López-Fonseca, Rubén,Gutiérrez-Ortiz, Miguel ángel,Gutiérrez-Ortiz, Jose Ignacio
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- Kinetics of the liquid-phase hydrochlorination of methanol
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The kinetics of the liquid-phase hydrochlorination of methanol with hydrogen chloride in the absence of a catalyslt is reported. A kinetic equation is suggested for the reaction. The values of the preexponential factor, activation energy, and empiric coefficients characterizing the influence of the hydration of the chlorine anion on the rate of hydrochlorination have been.
- Makhin,Zanaveskin,Dmitriev
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- Boron halide chelate compounds and their activity towards the demethylation of trimethylphosphate
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Salen(t-Bu)H2 (N,N′-ethylenebis(3,5-di-tert-butyl(2-hydroxy)benzylidenimine) and its derivatives were used to prepare boron compounds having the formula L(BCl2)2 (L = salen(t-Bu) (1), salpen(t-Bu) (2), salben(t-Bu) (3), salpten(t-Bu) (4), salhen(t-Bu) (5)). These are formed from the reaction of the corresponding (L[B(OMe)2]2 with BCl3. In addition to being a new type of boron compound, they are also potential two-point Lewis acids. Indeed, they demonstrate Lewis acidic behavior in the dealkylation of trimethylphosphate. All of the compounds were characterized by mp, elemental analysis, 1H and 11B NMR, IR, MS, and in the case of 2 by X-ray crystallography.
- Keizer, Timothy S.,De Pue, Lauren J.,Parkin, Sean,Atwood, David A.
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- On the mechanism of catalytic oxidation of CH2Cl2 on γ-Al2O3 and its oscillatory behaviour
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Adsorption of CH2Cl2 and its oxidation with dioxygen have been investigated on pure γ-Al2O3 by means of infrared spectroscopy and gas chromatographic analysis. Infrared spectroscopy showed that CH2Cl2 may be adsorbed on the alumina surface through chlorine ions either on two adjacent exposed Al ions at the (111) plane of Al2O3, or on the isoloated Lewis acid sites. The oxidation of CH2Cl2 at temperatures below 450°C yields an intermediate product CH3Cl with 50% of selectivity whereas the other half of the CH2Cl2 amount is totally oxidized to CO2 and HCl. At temperatures higher than 450°C practically total conversion of CH2Cl2 to CO2 and HCl takes place. Selfsustained oscillations of the CH2Cl2 conversion in a broad range are observed when water vapour is added to the feed. The mechanism explaining the nature of the activity of alumina in the CH2Cl2 oxidation and selectivity to CH3Cl as well as a possible reason of oscillations of the conversion are proposed. by R. Oldenbourg Verlag, 1996.
- Haber, Jerzy,Machej, Tadeusz,Derewiński, Miros?aw,Janik, Robert,Kry?ciak, Joanna,Sadowska, Halina
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- Looking for a contribution of the non-equilibrium solvent polarization to the activation barrier of the SN2 reaction
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The solvent effect on the activation free energy of the Finkelstein reaction between methyl iodide and Cl- ions was analysed in terms of the recent Marcus theory unifying the SN2 and the electron transfer reactions. The homolytic bond dissociation energy and the related resonance energy of interaction of the states seem to be almost solvent independent. The sum of the work term Wr and the solvent reorganization energy λ0/4 depends strongly on the solvent acidity parameter, e.g. ETN, describing the solvation/desolvation of anions. However, after removing the contribution of the specific solvation the linear increase of the remaining part of λ0/4 with the Pekar factor, describing the non-equilibrium solvent polarization, was observed for six aprotic solvents. Copyright
- Jaworski, Jan S.
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- Highly Selective Catalytic Dechlorination of Dichloromethane to Chloromethane over Al?Ti Mixed Oxide Catalysts
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In this paper, a series of Al?Ti mixed oxides with different Al/Ti ratios are prepared by a simple sol-gel method and they are used as active catalysts for selective dechlorination of dichloromethane to chloromethane. The Al?Ti mixed oxide catalyst with the same molar ratio of Al and Ti shows the highest activity in dechlorination of dichloromethane. The strong and abundant Lewis acid sites in the Al?Ti mixed oxides formed along with Al?O?Ti bondings are responsible for the high catalytic activity toward the selective dechlorination reaction in this work. From a kinetic study, the activation energy of this reaction over the optimum Al?Ti mixed oxide catalyst appears to be 59.4 kJ mol?1 based on Langmuir-Hinshelwood model. The improved catalytic performance suggests that the Al?Ti mixed oxide could be used as the effective catalyst for the highly selective dechlorination of dichloromethane to chloromethane.
- Yoon, Wongeun,Lee, Seungjun,Noh, Yuseong,Park, Seongmin,Kim, Youngmin,Ju Kim, Hyung,Chae, Ho-Jeong,Bae Kim, Won
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- Detailed kinetic investigation of the C2H5 + Cl2 reaction and analysis of the reaction of CH3 + Cl2 initiated by H-atom contamination at 298 K and at millitorr pressures
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The bimolecular reaction: C2H5+Cl2 →4 C2H5Cl+Cl is studied in the very low pressure reactor (VLPR) system at 298 K starting with Cl/C2H6/Cl2 mixtures. Mass conservation is found to be 97±3% for the overall chemical change in the system. From the C2H5Cl product formation kinetics, k4 = (1.05±0.05) · 10-12 cm3/(molecule-s) is derived. Two independent estimates of the A factor gives A4 = 1.3 · 10-12 cm3/(molecule-s). These parameters yield a positive activation energy of 0.13 kcal/mol in contrast with recently reported negative activation energy values. Some side reactions of small extent are initiated by H atom contamination in the system. The measurement of CH3Cl product formed from CH3+Cl2 →11 CH3Cl+Cl gives k11 = (3.4±0.3) · 10-12 cm3/(molecule-s) with an estimated A factor of A11 = 5.0 · 10-12 cm3/(molecules). The source of CH3 radicals is the side reaction H+C2H5 → 2CH3. by Oldenbourg Wissenschaftsverlag, Muenchen.
- Dobis, Otto,Benson, Sidney W.
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- Kinetics and thermochemistry of the R + HBr ? RH + Br (R = CH2Cl, CHCl2, CH3CHCl or CH3CCl2) equilibrium
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The kinetics of the reactions of CH2Cl, CHCl2, CH3CHCl and CH3CCl2 with HBr have been investigated in a heatable tubular reactor coupled to a photoionization mass spectrometer. The radicals, R, were produced homogeneously in the reactor by pulsed 248 nm exciplex laser photolysis. The decay of R was monitored as a function of HBr concentration under pseudo-first-order conditions to determine the rate constants as a function of temperature and pressure range. The reactions were studied separately over a wide temperature range and at these temperature ranges the rate constants determined were fitted to an Arrhenius expression (error limits stated are 1σ + Student's t values, units in cm3 molecule-1 s-1): k(CH2Cl) = (6.6 ± 1.7) × 10-13 exp[-(4.1 ± 0.2) kJ mol-1/RT], k(CHCl2) = (4.1 ± 1.0) × 10-13 exp[-(9.8 ± 1.0) kJ mol-1/RT], k(CH3CHCl) = (3.0 ± 0.9) × 10-13 exp[+(3.0 ± 0.2) kJ mol-1/RT] and k(CH3CCl2) = (4.4 ± 0.9) × 10-13 exp[-(5.9 ± 0.7) kJ mol-1/RT]. The kinetic information obtained was combined with the what is known of the recently measured rate constants of the reverse reactions to calculate the entropy and the heat of formation values of the radicals studied. The thermodynamic values were obtained at 298 K using a second law procedure. The results for entropy values are as follows (units in J K-1 mol-1): 271 ± 7 (CH2Cl), 280 ± 7 (CHCl2), 279 ± 6 (CH3CHCl) and 288 ± 5 (CH3CCl2). The results for ΔfH°298 are as follows (units in kJ mol-1): 117.3 ± 3.1 (CH2Cl), 89.0 ± 3.0 (CHCl2), 76.5 ± 1.6 (CH3CHCl) and 42.5 ± 1.7 (CH3CCl2). The C-H bond energy of analogous chlorinated hydrocarbons derived from the enthalpy of reaction values are as follows (units in kJ mol-1): 419.0 ± 2.3 (CH3Cl), 402.5 ± 2.7 (CH2Cl2), 406.6 ± 1.5 (α-C-H bond in CH3CH2Cl) and 390.6 ± 1.5 (α-C-H bond in CH3CHCl2). Improved heats of formation for the CH2ClO2 radical, ΔfH°298(CH2ClO2) = -(4 ± 11) kJ mol-1, and for the CHCl2O2 radical, ΔfH°298(CHCl2O2) = -(17 ± 7) kJ mol-1 are also calculated from the previously measured R′ + O2 ? R′O2 (R′ = CH2Cl or CHCl2) equilibriums.
- Seetula, Jorma A.
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- Photochemistry of adsorbed molecules. XII. Photoinduced ion-molecule reactions at a metal surface for CH3X/RCl/Ag(111) (X = Br, I)
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A photoinduced ion-molecule reaction is reported between superimposed molecular layers of alkyl halides on a metal substrate CH3X/RCl/Ag(111) (where X = Br or I and R = CCl3, CHCl2, or CH2Cl) to form CH3Cl(ad) (wavelengths 193, 248, and 350 nm).The reaction is mediated by charge-transfer (CT) photodissociation, in which photoelectrons from the metal surface transfer to the lower layer of adsorbate RCl to form RCl-.These negative ions then react with the upper layer CH3X in an ion-molecule reaction to form CH3Cl + X-.The yield of product CH3Cl is found to be enhanced at ca. 1 ML of adsorbed CH3X (upper layer) due to a decrease in the local potential in the region of the adsorbate-adsorbate interface that enhances the probability of CT to the lower layer.In addition to lowering the local potential at the interface, the adsorbed CH3X also lowers the surface work function; as a result changes in the microscopic local potential correlate (via the CT reaction rate) with changes in the observed macroscopic work function.The yield of CH3Cl decreases at still higher CH3X coverage in the upper layer as the work fuction increases.The ion-molecule reaction give evidence of being a concerted process in which the Cl- reacts as it separates from RCl- rather than following separation.The reagent RCl-, as in the surface reaction discussed in the previous paper, is formed by CT from "hot" electrons rather than free photoelectrons.
- Dixon-Warren, St. J.,Heyd, D. V.,Jensen, E. T.,Polanyi, J. C.
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- Observation of the XY- abstraction products in the ion-molecule reactions X- + RY → XY- + R: An alternative to the SN2 mechanism at suprathermal collision energies
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We report the formation of dihalide products from the endothermic gas-phase ion-molecule reaction of Cl- with CH3Br at suprathermal collision energies using both guided ion beam and selected ion flow drift tube (SIFDT) techniques. The cross sections for the Cl- + CH3Br reactions were determined using the guided ion beam apparatus over a center-of-mass collision energy range of 2-15 eV with the ClBr- product displaying a maximum near 7 eV. This result is found to be in good agreement (when convoluted with the appropriate velocity distribution) with the rate constant measured by the SIFDT. ICl- and I2- are also found for the Cl- + CH3I and I- + RI reactions at elevated collision energies (≤1.5 eV) in the SIFDT. The rates for halide displacement are found to be insensitive to collision energy. These results indicate that attack on the C-X bond may not provide an efficient alternative to the SN2 mechanism for halide exchange in the asymmetric X- + CH3Y systems. This conclusion is supported by ab initio calculations (MP2LANL10Z level) which indicate that ClBr- can be formed by collinear attack at the halogen through a Cl?Br?CH3 intermediate.
- Cyr, Donna M.,Scarton, M. Georgina,Wiberg, Kenneth B.,Johnson, Mark A.,Nonose, Shinji,Hirokawa, Jun,Tanaka, Hideki,Kondow, Tamotsu,Morris, Robert A.,Viggiano
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- Trialkylammonium salt degradation: Implications for methylation and cross-coupling
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Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
- Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
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p. 6949 - 6963
(2021/06/02)
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- A process of preparing methyl chloride using multistage reaction
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The present invention relates to a method of producing methyl chloride by multistage reactions. The method of the present invention comprises: a) a chlorination step for sufficiently increasing the conversion rate of methane, which is an initial reactant; and b) a subsequent reaction step for actively utilizing hydrogen chloride (HCl), which is a hazardous byproduct of chlorination, efficiently treating harmful hydrogen chloride, and at the same time, improving the overall production of methyl chloride.COPYRIGHT KIPO 2020
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Paragraph 0092-0100; 0112
(2020/06/10)
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- Control of methane chlorination with molecular chlorine gas using zeolite catalysts: Effects of Si/Al ratio and framework type
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CH4 chlorination with Cl2 gas is used for the production of chlorinated products via C–H bond activation in CH4. Due to the high reactivity of Cl2, this reaction can occur spontaneously under UV irradiation or with mild thermal energy even in the absence of a catalyst via a free radical-mediated chain reaction mechanism that undesirably causes excessive chlorination of the CH4 and is thus non-selective. In this work, CH4 chlorination is investigated using HY and MFI zeolites with various Si/Al ratios, by which the reaction is catalytically controlled for selective production of the mono-chlorinated product (CH3Cl). Depending on the framework type, Si/Al ratio of the zeolites, and reaction conditions, different degrees of CH4 conversion, CH3Cl selectivity, and hence CH3Cl yield were achieved, by which systematic relationships between the catalyst properties and performance were discovered. A high aluminum content facilitated the production of CH3Cl with up to ~20 % yield at a high gas hourly space velocity of 2400 cm3gcat?1 h?1 with a CH4/Cl2 ratio of 1 at 350 °C. HY zeolites generally furnished a slightly higher CH3Cl yield than MFI zeolites, which can be attributed to the larger micropores of the HY zeolites that support facile molecular diffusion. With various flow rates and ratios of CH4 and Cl2, the CH4 conversion and CH3Cl selectivity changed simultaneously, with a trade-off relationship. Unfortunately, all zeolite catalysts suffered from framework dealumination due to the HCl produced during the reaction, but it was less pronounced for the zeolites having a low aluminum content. The results shed light on the detailed roles of zeolites as solid-acid catalysts in enhancing CH3Cl production during electrophilic CH4 chlorination.
- Kwon, Seungdon,Chae, Ho-Jeong,Na, Kyungsu
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p. 111 - 117
(2020/01/31)
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- Sulfated Tin Oxide as Highly Selective Catalyst for the Chlorination of Methane to Methyl Chloride
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The chlorination of methane (CH4) is an attractive route to convert CH4 into more valuable chemicals. The selective formation of methyl chloride (CH3Cl) is a key process, but it is rather difficult to achieve with high selectivity due to a radical reaction. Catalytic ionic processes can be a solution. Herein, sulfated tin oxide (STO) was employed in the gas-phase catalytic chlorination of CH4. The STO catalyst exhibited high selectivity to CH3Cl (>96%) even at high CH4 conversion. By applying a suite of physicochemical characterizations, it is shown that the strong Lewis acid sites on STO generated by the interaction of Sn and surface sulfate groups are mainly responsible for the highly selective CH4 conversion. DFT calculations further revealed that STO surface can activate more Cl2 molecules in a heterolytic manner, leading to better catalytic performances as compared to SnO2 and sulfated zirconia catalysts.
- Kim, Youngmin,Kim, Jip,Kim, Hyun Woo,Kim, Tae-Wan,Kim, Hyung Ju,Chang, Hyunju,Park, Min Bum,Chae, Ho-Jeong
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p. 9398 - 9410
(2019/10/11)
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- Method of preparing methyl chloride and catalyst for preparing methyl chloride
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Disclosed are a method for preparing methyl chloride and a catalyst for preparing methyl chloride. According to the method for preparing methyl chloride, a hydrogen chloride reaction of methanol is used in the presence of a catalyst. The catalyst comprises an alumina catalyst having the total acid site amount of 1.654-2.835 mmol/g. A conversion ratio of methanol and an yield of methyl chloride can be improved.(AA) Harvest rate of methyl chloride(%)(BB) Catalyst group of embodiment example(CC) Entire acid site amount(mmol/g)COPYRIGHT KIPO 2019
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Paragraph 0054-0055; 0067
(2019/10/11)
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- A process of preparing methyl chloride using multistage reaction and separation
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The present invention relates to a method for producing methyl chloride by a multi-stage reacting and separating step, which comprises the steps of: forming a first product including chlorides other than methyl chloride, unreacted methane and unreacted chlorine gas; separating and recovering the methyl chloride, and forming a second product consisting of the other chlorides; forming a third product including the methyl chloride, other unreacted chlorines and unreacted methanol; and separating and recovering the methyl chloride.COPYRIGHT KIPO 2019
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Paragraph 0020; 0072-0076
(2019/05/01)
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- A Very Strong Methylation Agent: [Me2Cl][Al(OTeF5)4]
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A new chloronium-containing salt, [Me2Cl][Al(OTeF5)4], was synthesized on multigram scale by means of a simple one-pot procedure. The isolated product can be handled at room temperature and used as a strong electrophilic methylation agent. This is demonstrated by the methylation of the very weak bases P(CF3)3, PF3, MeI, and MeBr.
- H?mmerling, Sebastian,Thiele, Günther,Steinhauer, Simon,Beckers, Helmut,Müller, Carsten,Riedel, Sebastian
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supporting information
p. 9807 - 9810
(2019/06/24)
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- An Activated TiC–SiC Composite for Natural Gas Upgrading via Catalytic Oxyhalogenation
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Alkane oxyhalogenation has emerged as an attractive catalytic route for selective natural gas functionalization to important commodity chemicals, such as methyl halides or olefins. However, few systems have been shown to be active and selective in these reactions. Here, we identify a novel and highly efficient TiC–SiC composite for methane and ethane oxyhalogenation. Detailed characterization elucidates the kinetics and mechanism of the selective activation under reaction conditions to yield TiO2–TiC–SiC. This catalyst outperforms bulk TiO2, one of the best reported catalysts, reaching up to 85 % selectivity and up to 3 times higher titanium-specific space-time-yield of methyl halides or ethylene. This is attributed to the fact that the active TiO2 phase generated in situ is embedded in the thermally conductive SiC matrix, facilitating heat dissipation thus improving selectivity control.
- Zichittella, Guido,Puértolas, Bego?a,Siol, Sebastian,Paunovi?, Vladimir,Mitchell, Sharon,Pérez-Ramírez, Javier
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p. 1282 - 1290
(2018/02/09)
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- Mechanism of Hydrocarbon Functionalization by an Iodate/Chloride System: The Role of Ester Protection
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Mixtures of chloride and iodate salts for light alkane oxidation achieve >20% yield of methyl trifluoroacetate (TFA) from methane with >85% selectivity. The mechanism of this C-H oxygenation has been probed by examining adamantane as a model substrate. These recent results lend support to the involvement of free radicals. Comparative studies between radical chlorination and iodate/chloride functionalization of adamantane afford statistically identical 3°:2° selectivities (~5.2:1) and kinetic isotope effects for C-H/C-D functionalization (kH/kD = 1.6(3), 1.52(3)). Alkane functionalization by iodate/chloride in HTFA is proposed to occur through H-atom abstraction by free radical species including Cl? to give alkyl radicals. Iodine, which forms by in situ reduction of iodate, traps alkyl radicals as alkyl iodides that are subsequently converted to alkyl esters in HTFA solvent. Importantly, the alkyl ester products (RTFA) are quite stable to further oxidation under the oxidizing conditions due to the protecting nature of the ester moiety.
- Schwartz, Nichole A.,Boaz, Nicholas C.,Kalman, Steven E.,Zhuang, Thompson,Goldberg, Jonathan M.,Fu, Ross,Nielsen, Robert J.,Goddard, William A.,Groves, John T.,Gunnoe, T. Brent
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p. 3138 - 3149
(2018/04/14)
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- A Light-Releasable Potentially Prebiotic Nucleotide Activating Agent
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Investigations into the chemical origin of life have recently benefitted from a holistic approach in which possible atmospheric, organic, and inorganic systems chemistries are taken into consideration. In this way, we now report that a selective phosphate activating agent, namely methyl isocyanide, could plausibly have been produced from simple prebiotic feedstocks. We show that methyl isocyanide drives the conversion of nucleoside monophosphates to phosphorimidazolides under potentially prebiotic conditions and in excellent yields for the first time. Importantly, this chemistry allows for repeated reactivation cycles, a property long sought in nonenzymatic oligomerization studies. Further, as the isocyanide is released upon irradiation, the possibility of spatially and temporally controlled activation chemistry is thus raised.
- Mariani, Angelica,Russell, David A.,Javelle, Thomas,Sutherland, John D.
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supporting information
p. 8657 - 8661
(2018/07/15)
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- DICHLOROMETHANE REDUCTION FROM A METHANE OXYCHLORINATION PRODUCT STREAM
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A chemical reactor system includes: a feed; a methane oxychlorination catalyst, wherein a product of an oxychlorination reaction is dichloromethane; and a dichloromethane conversion catalyst, wherein the dichloromethane conversion catalyst provides a product stream having a dichloromethane selectivity less than 5%. The addition of the dichloromethane conversion catalyst to the reactor bed can decrease the amount of dichloromethane produced and increase the amount of monochloromethane produced. Accordingly, dichloromethane does not have to be separated from the product stream and the monochloromethane can then be used to produce other products, such as olefins.
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Paragraph 0027-0039
(2018/08/25)
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- Preparation method of chlorophenoxycarboxylic acid herbicide
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The invention provides a preparation method of a chlorophenoxycarboxylic acid herbicide, wherein the preparation method includes the following steps: A) carrying out hydrolysis reaction of chlorophenoxycarboxylic ester under the catalytic action of hydrochloric acid and metal chloride; B) after the reaction is finished, dividing the system into an oil phase and a water phase, and cooling and crystallizing the oil phase, to obtain chlorophenoxycarboxylic acid. Hydrochloric acid and metal chloride are used as a compound catalyst; in the reaction process, the raw material and the catalyst are fully contacted, the reaction rate is increased, the reaction time is shortened, and the reaction is more thorough; after the reaction is finished, the oil phase and the water phase are stratified to facilitate the separation of the product and the catalyst. Excess hydrochloric acid can be evaporated and recycled, water-washing water can be recycled, no waste salt or waste water exists, the energy consumption is low, and the preparation method is economic and environmentally friendly.
- -
-
Paragraph 0034-0043
(2019/01/08)
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- One-Pot Conversion of Methane to Light Olefins or Higher Hydrocarbons through H-SAPO-34-Catalyzed in Situ Halogenation
-
Methane was converted to light olefins (ethene and propene) or higher hydrocarbons in a continuous flow reactor below 375 °C over H-SAPO-34 catalyst via an in situ halogenation (chlorination/bromination) protocol. The reaction conditions can be efficiently tuned toward selective monohalogenation of methane to methyl halides or their in situ oligomerization to higher hydrocarbons. The presence of C5+ hydrocarbons in the reaction products clearly indicates that by using a properly engineered catalyst under optimized reaction conditions, hydrocarbons in the gasoline range can be produced. This approach has significant potential for feasible application in natural gas refining to gasoline and materials under moderate operational conditions.
- Batamack, Patrice T. D.,Mathew, Thomas,Prakash, G. K. Surya
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p. 18078 - 18083
(2017/12/26)
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- Selective reduction of a C–Cl bond in halomethanes with Et3GeH at nanoscopic Lewis acidic Aluminium fluoride
-
The selective activation of C–Cl bonds of hydrochlorofluoromethanes and chloromethanes at moderate reaction conditions using ACF in a combination with Et3GeH is presented. The reactions of the chloromethanes (CH3Cl, CH2Cl2, CHCl3 and CCl4) in the presence of Et3GeH and ACF as catalyst led to the activation of only one C–Cl bond resulting in the hydrodechlorination. Friedel-Crafts reactions with benzene as solvent are suppressed by Et3GeH. A selective hydrodechlorination of hydrochlorofluoromethanes was achieved, because a transformation of a C–F bond into a C–H bond by the combination of ACF with Et3GeH did not occur. Supporting PulseTA experiments illustrated the interaction between the solid catalyst and Et3GeH, the solvent benzene or CH2Cl2.
- Mei?ner, Gisa,Feist, Michael,Braun, Thomas,Kemnitz, Erhard
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p. 234 - 241
(2017/09/12)
-
- Reaction system for increasing utilization ratio of reactants in chloromethane production and application of reaction system
-
The invention relates to a reaction system for increasing utilization ratio of reactants in chloromethane production and an application of the reaction system. The system comprises a reaction unit, a condenser and a return tank, wherein the reaction unit comprises 2 to 5 reactors which are in series connection, a reactor charging opening I is formed in the bottom end of each reactor, a reactor discharging opening and a reactor charging opening II are formed in the top end of each reactor, a discharging opening of the reaction unit is connected with a condenser charging opening of the condenser, a condenser discharging opening of the condenser is connected with a return tank charging opening of the return tank, a return tank discharging opening I and a return tank discharging opening II are separately formed in the top end and bottom end of the return tank, and the return tank discharging opening II of the return tank is separately connected with the reactor charging openings II of all the reactors. The reaction system disclosed by the invention is applied to the production of chloromethane from methanol and hydrogen chloride, which serve as raw materials, and the methanol and the hydrogen chloride can be in full reaction as much as possible, so that the arranging of a methanol recovery device and a hydrogen chloride recovery device is avoided, energy is saved, and environmental pollution is reduced.
- -
-
Paragraph 0038; 0039; 0040; 0041; 0042; 0043; 0044
(2017/01/17)
-
- Methyl chloride synthesis method
-
The invention relates to a methyl chloride synthesis method, which is characterized in that hydrochloric acid and methanol are directly mixed; hydrochloric acid is directly synthesized under a certain condition; the product of methyl chloride is obtained through condensing, drying and compressing; synthesized condensing liquid is rectified to recover unreacted methanol for reaction again.
- -
-
Paragraph 0032; 0034; 0035; 0036; 0037; 0038; 0039-0044
(2017/06/02)
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- Hollow anatase TiO2 nanoparticles with excellent catalytic activity for dichloromethane combustion
-
Toward the design of efficient nanocatalysts, hollow anatase TiO2 nanoparticles around 11.4 nm in size were prepared by a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. The catalyst showed high catalytic activity for dichloromethane (DCM) combustion, exhibiting 90% DCM conversion at 201 °C. The satisfactory performance of the catalyst was attributed to its hollow texture with many active sites, and the large number of moderately strong acidic sites on the hollow TiO2 surface.
- Huang, Haifeng,Zhang, Xixiong,Jiang, Xiaojia,Dou, Kang,Ni, Zhiyi,Lu, Hanfeng
-
p. 61610 - 61614
(2016/07/11)
-
- Methyl chloride washing technology in glyphosate production
-
The invention provides a methyl chloride washing technology in glyphosate production. The preparation technology comprises the following steps of: firstly, carrying out condensation reaction on paraformaldehyde and dimethyl phosphate under the action of methanol and triethylamine; generating a glyphosate acid under the action of hydrochloric acid, and generating a lot of tail gas containing methyl chloride; carrying out primary washing on the tail gas through a first washing tower, carrying out secondary washing on the firstly washed gas through a second washing tower, removing a residual hydrogen chloride gas from the secondly washed gas through a sodium hydroxide solution, and carrying out tertiary washing on the gas through a third washing tower; removing impurities in a methyl chloride tail gas from the thirdly washed gas through activated carbon; and finally heating the gas treated through the activated carbon and further purifying the methyl chloride. By the production technology, consumption of methanol in production can be reduced by methyl chloride washing water recycling treatment; the production cost is lowered.
- -
-
Paragraph 0020-0021
(2017/03/28)
-
- Reactivity of [WCl6] with Ethers: A Joint Computational, Spectroscopic and Crystallographic Study
-
The reactions of [WCl6] with a series of ethers have been performed in chlorinated solvent and elucidated by means of analytical, spectroscopic and DFT methods. The addition of tetrahydropyran (thp) or 1,4-dioxane to [WCl6] resulted in the reversible formation of the adducts WCl6···L [L = thp (1a), 1,4-dioxane (1b)], detected in solution by NMR spectroscopy. The reaction of [WCl6] with thp in a molar ratio of 1:2 in chloroform at reflux afforded [WOCl4(thp)] (2a), which was isolated in 51 % yield. [WOCl4(OMe2)] (2b) and [WOCl3(OMe2)2] (3a) were isolated in yields of 53 and 18 %, respectively, from the reaction of [WCl6] with an excess of dimethyl ether. [WOCl3(OEt2)2] (3b) was the only identified metal compound produced from the reaction of [WCl6] and OEt2(1:2 molar ratio). According to NMR studies, the oxide ligand in 2a,b and 3a,b was generated by double C–O bond cleavage involving one equivalent of organic reactant. The 1:1 reaction of [WCl6] with 1,2-diethoxyethane led to [WCl5(κ1-OCH2CH2OEt)] (4) and a minor amount of [WCl4(κ2-EtOCH2CH2OEt)] (5). The aryl oxide compound [WCl5(OPh)] (6) was prepared in 62 % yield from the reaction of [WCl6] and anisole by selective Csp3–O bond activation. The prolonged heating of a mixture of [WCl6] and diphenyl ether in 1,2-dichloroethane led to the isolation of the WVcomplex [WCl5(OPh2)] (7). The molecular structures of 2a and 3a were ascertained by X-ray diffraction.
- Bortoluzzi, Marco,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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p. 3169 - 3177
(2016/07/14)
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- Onion-Like Graphene Carbon Nanospheres as Stable Catalysts for Carbon Monoxide and Methane Chlorination
-
Thermal treatment induces a modification in the nanostructure of carbon nanospheres that generates ordered hemi-fullerene-type graphene shells arranged in a concentric onion-type structure. The catalytic reactivity of these structures is studied in comparison with that of the parent carbon material. The change in the surface reactivity induced by the transformation of the nanostructure, characterized by TEM, XRD, X-ray photoelectron spectroscopy (XPS), Raman, and porosity measurements, is investigated by multipulses of Cl2 in inert gas or in the presence of CH4 or CO. The strained C-C bonds (sp2-type) in the hemi-fullerene-type graphene shells induce unusually strong, but reversible, chemisorption of Cl2 in molecular form. The active species in CH4 and CO chlorination is probably in the radical-like form. Highly strained C-C bonds in the parent carbon materials react irreversibly with Cl2, inhibiting further reaction with CO. In addition, the higher presence of sp3-type defect sites promotes the formation of HCl with deactivation of the reactive C-C sites. The nano-ordering of the hemi-fullerene-type graphene thus reduces the presence of defects and transforms strained C-C bonds, resulting in irreversible chemisorption of Cl2 to catalytic sites able to perform selective chlorination. Tidy up the carbon! CO and CH4 chlorination over hemi-fullerene-type graphene is described. The surface nano-ordering, induced by thermal treatment, transforms strained C-C bond sites resulting in irreversible Cl2 chemisorption to catalytic sites that are able to selectively chlorinate CO and CH4.
- Centi, Gabriele,Barbera, Katia,Perathoner, Siglinda,Gupta, Navneet K.,Ember, Erika E.,Lercher, Johannes A.
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p. 3036 - 3046
(2015/09/22)
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- Preparation of selective ZnCl2/alumina catalysts for methyl chloride synthesis: Influence of pH, precursor and zinc loading
-
Zinc-modified alumina catalysts for methyl chloride synthesis were prepared with varying zinc loadings: from 2.4 to 21.1 wt%. The influence of the zinc loading, zinc precursor and the pH of the impregnation on the physico-chemical properties of the catalyst, and on the catalyst activity and selectivity for methyl chloride (MeCl) synthesis was investigated. The prepared catalysts were thoroughly characterized by FTIR, TEM, physisorption and EDX. On the alumina surface, both molecular and bulk zinc species are created upon zinc loading. The surface area of the catalyst decreases steadily with zinc loading. Bulk zinc species dominate on the catalyst starting at a zinc loading of 9.4 wt% and the amount of Lewis acid sites (LAS) decreases. A shift in the acid site type takes place upon zinc modification. Sites assigned to stronger LAS are eliminated while zinc-based weaker acid sites started to predominate. The shift in acidity increases the selectivity and activity of methyl chloride synthesis, which was demonstrated in a series of experiments in a laboratory-scale fixed bed reactor.
- Schmidt, Sabrina A.,Peurla, Markus,Kumar, Narendra,Er?nen, Kari,Murzin, Dmitry Yu.,Salmi, Tapio
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p. 117 - 127
(2015/05/05)
-
- Preparation of selective ZnCl2/alumina catalysts for methyl chloride synthesis: Influence of pH, precursor and zinc loading
-
Zinc-modified alumina catalysts for methyl chloride synthesis were prepared with varying zinc loadings: from 2.4 to 21.1 wt%. The influence of the zinc loading, zinc precursor and the pH of the impregnation on the physico-chemical properties of the catalyst, and on the catalyst activity and selectivity for methyl chloride (MeCl) synthesis was investigated. The prepared catalysts were thoroughly characterized by FTIR, TEM, physisorption and EDX. On the alumina surface, both molecular and bulk zinc species are created upon zinc loading. The surface area of the catalyst decreases steadily with zinc loading. Bulk zinc species dominate on the catalyst starting at a zinc loading of 9.4 wt% and the amount of Lewis acid sites (LAS) decreases. A shift in the acid site type takes place upon zinc modification. Sites assigned to stronger LAS are eliminated while zinc-based weaker acid sites started to predominate. The shift in acidity increases the selectivity and activity of methyl chloride synthesis, which was demonstrated in a series of experiments in a laboratory-scale fixed bed reactor.
- Schmidt, Sabrina A.,Peurla, Markus,Kumar, Narendra,Er?nen, Kari,Murzin, Dmitry Yu,Salmi, Tapio
-
p. 117 - 127
(2015/05/06)
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- Gas phase reaction of phosphorus trichloride and methanol: Matrix isolation infrared and DFT studies
-
Abstract Gas phase reaction of phosphorus trichloride (PCl3) and methanol (CH3OH) was carried out with different ratios of PCl3:CH3OH:N2 (1:1:1000, 1:2:1000 and 1:3:1000) and the products were identified using matrix isolation infrared spectroscopy. For the 1:1 and 1:2 ratios of PCl3:CH3OH, dichloro methyl phosphite (DCMP) and methyl chloride (CH3Cl) were the products formed. Interestingly, only methyl chloride (CH3Cl) was observed for the 1:3 ratio of PCl3:CH3OH. DFT computations were carried out at B3LYP/6-311++G(d,p) level of theory to give insights into the formation of the reaction products. Based on the experimental findings and computations a reaction mechanism has been proposed through a nucleophilic substitution reaction to explain the formation of the products.
- Joshi, Prasad Ramesh,Ramanathan,Sundararajan,Sankaran
-
-
- Hydrodechlorination of CCl4 over carbon-supported palladium-gold catalysts prepared by the reverse "water-in-oil" microemulsion method
-
Two series of carbon-supported Pd-Au catalysts were prepared by the reverse "water-in-oil, W/O" method, characterized by various techniques and investigated in the reaction of tetrachloromethane with hydrogen at 423K. The synthesized nanoparticles were reasonably monodispersed having an average diameter of 4-6nm (Pd/C and Pd-Au/C) and 9nm (Au/C). Monometallic palladium catalysts quickly deactivated during the hydrodehalogenation of CCl4. Palladium-gold catalysts with molar ratio Pd:Au=90:10 and 85:15 were stable and much more active than the monometallic palladium and Au-richer Pd-Au catalysts. The selectivity toward chlorine-free hydrocarbons (especially for C2+ hydrocarbons) was increased upon introducing small amounts of gold to palladium. Simultaneously, for the most active Pd-Au catalysts, the selectivity for undesired dimers C2HxCly, which are considered as coke precursors, was much lower than for monometallic Pd catalysts. Reasons for synergistic effects are discussed. During CCl4 hydrodechlorination the Pd/C and Pd-Au/C catalysts were subjected to bulk carbiding.
- Bonarowska, Magdalena,Karpiński, Zbigniew,Kosydar, Robert,Szume?da, Tomasz,Drelinkiewicz, Alicja
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p. 1143 - 1151
(2015/11/11)
-
- Partial oxidation of light alkanes by periodate and chloride salts
-
The efficient and selective partial oxidation of light alkanes using potassium periodate and potassium chloride is reported. Yields of methane functionalization in trifluoroacetic acid reach >40% with high selectivity for methyl trifluoroacetate. Periodat
- Kalman, Steven E.,Munz, Dominik,Fortman, George C.,Boaz, Nicholas C.,Groves, John T.,Gunnoe, T. Brent
-
supporting information
p. 5294 - 5298
(2015/03/30)
-
- Catalytic low-temperature combustion of dichloromethane over V-Ni/TiO2 catalyst
-
Vanadium-nickel mixed oxides supported on TiO2 (anatase) were prepared by wet impregnation using ammonium metavanadate and nickel nitrate aqueous solution. The performance of as-prepared samples in catalytic dichloromethane (DCM) combustion was investigated, and their physicochemical properties were characterized in detail by X-ray diffraction, N2 physisorption, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, and Raman spectroscopy analyses. Results showed DCM combustion activity over V-Ni/TiO2 catalyst was superior to that of V2O5/TiO2 and NiO/TiO2 catalysts. DCM could be completely converted into CO2, HCl, and a little amount of CO over Ni-V/TiO2 catalyst at 350 °C, the toxic by-products, such as CH3Cl, aldehydes and phosgene could not be observed by online IR spectroscopy. The high catalytic activity, selectivity, and stability of V-Ni/TiO2 catalyst could be due to the good oxidative dehydrogenation ability (ODH), the good reducibility of active oxygen species, and suitable strength of Lewis acidic sites upon introduction of nickel oxide.
- Zhang, Xinhua,Pei, Zhiying,Ning, Xingjie,Lu, Hanfeng,Huang, Haifeng
-
p. 79192 - 79199
(2015/10/05)
-
- Evaluation of decomposition products of EMImCl·1.5AlCl3 during aluminium electrodeposition with different analytical methods
-
Ionic liquids are of great importance for electrodeposition of metals, which can't be deposited from aqueous electrolytes due to their negative standard potentials. In this paper non-woven polymers were coated with aluminium by electrodeposition from 1-et
- Poetz, Sandra,Handel, Patricia,Fauler, Gisela,Fuchsbichler, Bernd,Schmuck, Martin,Koller, Stefan
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p. 6685 - 6690
(2014/02/14)
-
- Selective monooxidation of light alkanes using chloride and iodate
-
We describe an efficient system for the direct partial oxidation of methane, ethane, and propane using iodate salts with catalytic amounts of chloride in protic solvents. In HTFA (TFA = trifluoroacetate), >20% methane conversion with >85% selectivity for MeTFA have been achieved. The addition of substoichiometric amounts of chloride is essential, and for methane the conversion increases from 20%. The reaction also proceeds in aqueous HTFA as well as acetic acid to afford methyl acetate. 13C labeling experiments showed that less than 2% of methane is overoxidized to 13CO2 at 15% conversion of 13CH4. The system is selective for higher alkanes: 30% ethane conversion with 98% selectivity for EtTFA and 19% propane conversion that is selective for mixtures of the mono- and difunctionalized TFA esters. Studies of methane conversion using a series of iodine-based reagents [I2, ICl, ICl3, I(TFA)3, I2O4, I 2O5, (IO2)2S2O 7, (IO)2SO4] indicated that the chloride enhancement is not limited to iodate.
- Fortman, George C.,Boaz, Nicholas C.,Munz, Dominik,Konnick, Michael M.,Periana, Roy A.,Groves, John T.,Brent Gunnoe
-
p. 8393 - 8401
(2014/06/24)
-
- Method for Producing Difluoroacetyl Chloride
-
A production method of difluoroacetyl chloride according to the present invention includes a chlorination step of bringing a raw material containing at least either a 1-alkoxy-1,1,2,2-tetrafluoroethane or difluoroacetyl chloride into contact with calcium chloride at a reaction enabling temperature. A production method of 2,2-difluoroethyl alcohol according to the present invention includes a catalytic reduction step of causing catalytic reduction of the difluoroacetyl chloride obtained by the above production method. By these methods, the difluoroacetyl fluoride can be efficiently converted to the difluoroacetyl chloride and to the 2,2-difluoroethyl alcohol.
- -
-
Paragraph 0092
(2013/03/26)
-
- Oxidative reactivity of (N2S2)PdRX complexes (R = Me, Cl; X = Me, Cl, Br): Involvement of palladium(III) and palladium(IV) intermediates
-
A series of (N2S2)PdRX complexes (N2S2 = 2,11-dithia[3.3](2,6) pyridinophane; R = X = Me, 1; R = Me, X = Cl, 2; R = Me, X = Br, 3; R = X = Cl, 4) were synthesized, and their structural and electronic properties were investigated. X-ray crystal structures
- Luo, Jia,Rath, Nigam P.,Mirica, Liviu M.
-
supporting information
p. 3343 - 3353
(2013/07/19)
-
- Transformation of methane to propylene: A two-step reaction route catalyzed by modified CeO2 nanocrystals and zeolites
-
Propylene from methane: The transformation of methane to propylene has been realized in a two-step route via CH3Cl or CH3Br. CeO 2 serves as an efficient and stable catalyst for the oxidative chlorination and bromination of methane to CH3Cl and CH 3Br. In the second step, a modified zeolite is highly a selective and stable catalyst for the conversion of CH3Cl or CH3Br into propylene. Copyright
- He, Jieli,Xu, Ting,Wang, Zhihui,Zhang, Qinghong,Deng, Weiping,Wang, Ye
-
supporting information; experimental part
p. 2438 - 2442
(2012/04/23)
-
- Using Methanesulfonyl Halide as a Key Intermediate for Methane Gas to Liquid Conversion and Raw Commodity Chemical Generation
-
Processes for converting a methane or a methane containing natural gas to a monohalogenated methane and other downstream basic commodity chemicals going through methanesulfonyl halide as a key intermediate, whereby following its formation, the methanesulfonyl halide is allowed to decompose under a substantially anhydrous condition, preferably in the presence of a catalyst complex, and whereby in addition to the monohalogenated halide, a hydrogen halide and a sulfur dioxide are also formed in the overall conversion, both of which may be recycled back to the beginning of the processes. Additionally, compositions utilizing such a key intermediate for the same purposes are also disclosed.
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Page/Page column 6
(2012/05/04)
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- Diverse C-C bond-forming reactions of bis(carbene)platinum(II) complexes
-
The platinum(0) complex Pt(PPh3)4 catalyzes coupling of the carbene ligands of (CO)5Cr{C(OMe)(p-MeOC6H 4)} (1). The stable bis(carbene)platinum(II) complexes Cl 2Pt{C(OMe)(Me)}2
- Klet, Rachel C.,Labinger, Jay A.,Bercaw, John E.
-
p. 6652 - 6657
(2012/11/07)
-
- Structural and reactivity comparison of analogous organometallic Pd(iii) and Pd(iv) complexes
-
The tetradentate ligands RN4 (RN4 = N,N′-di-alkyl-2,11-diaza[3,3](2,6)pyridinophane, R = Me or iPr) were found to stabilize cationic (RN4)PdMe2 and ( RN4)PdMeCl complexes in both PdIII and PdIV oxidation states. This allows for the first time a direct structural and reactivity comparison of the two Pd oxidation states in an identical ligand environment. The PdIII complexes exhibit a distorted octahedral geometry, as expected for a d7 metal center, and display unselective C-C and C-Cl bond formation reactivity. By contrast, the PdIV complexes have a pseudo-octahedral geometry and undergo selective non-radical C-C or C-Cl bond formation that is controlled by the ability of the complex to access a five-coordinate intermediate. The Royal Society of Chemistry 2012.
- Tang, Fengzhi,Qu, Fengrui,Khusnutdinova, Julia R.,Rath, Nigam P.,Mirica, Liviu M.
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p. 14046 - 14050
(2013/01/15)
-
- Kinetics of liquid-phase noncatalytic methanol hydrochlorination in hydrochloric acid
-
The kinetics of the liquid-phase noncatalytic hydrochlorination of methanol in hydrochloric acid is reported. The methyl chloride formation rate depends on the methanol concentration in hydrochloric acid and on the partial pressure of hydrogen chloride over hydrochloric acid. The activation energy of the reaction is 113 kJ/mol. The rate of the side process of dimethyl ether evolution is directly proportional to the methanol concentration and is inversely proportional to the partial pressure of hydrogen chloride over hydrochloric acid. The activation energy of the side reaction is about 33 kJ/mol. The results of the industrial implementation of methyl chloride synthesis from methanol and hydrochloric acid are in satisfactory agreement with the laboratory data.
- Rozanov,Treger
-
experimental part
p. 654 - 658
(2011/11/30)
-
- Rational design of phosphoinositide 3-kinase inhibitors that exhibit selectivity over the phosphoinositide 3-kinase isoform
-
Of the four class I phosphoinositide 3-kinase (PI3K) isoforms, PI3K has justly received the most attention for its potential in cancer therapy. Herein we report our successful approaches to achieve PI3K vs PI3K selectivity for two chemical series. In the thienopyrimidine series of inhibitors, we propose that select ligands achieve selectivity derived from a hydrogen bonding interaction with Arg770 of PI3K that is not attained with the corresponding Lys777 of PI3K. In the benzoxepin series of inhibitors, the selectivity observed can be rationalized by the difference in electrostatic potential between the two isoforms in a given region rather than any specific interaction.
- Heffron, Timothy P.,Wei, Binqing,Olivero, Alan,Staben, Steven T.,Tsui, Vickie,Do, Steven,Dotson, Jennafer,Folkes, Adrian J.,Goldsmith, Paul,Goldsmith, Richard,Gunzner, Janet,Lesnick, John,Lewis, Cristina,Mathieu, Simon,Nonomiya, Jim,Shuttleworth, Stephen,Sutherlin, Daniel P.,Wan, Nan Chi,Wang, Shumei,Wiesmann, Christian,Zhu, Bing-Yan
-
experimental part
p. 7815 - 7833
(2012/01/05)
-
- Bis- N -heterocyclic carbene palladium(IV) tetrachloride complexes: Synthesis, reactivity, and mechanisms of direct chlorinations and oxidations of organic substrates
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This Article describes the preparation and isolation of novel octahedral CH2-bridged bis-(N-heterocyclic carbene)palladium(IV) tetrachlorides of the general formula LPdIVCl4 [L = (NHC)CH 2(NHC)] from LPdIICl2 and Cl2. In intermolecular, nonchelation-controlled transformations LPdIVCl 4 reacted with alkenes and alkynes to 1,2-dichlorination adducts. Aromatic, benzylic, and aliphatic C-H bonds were converted into C-Cl bonds. Detailed mechanistic investigations in the dichlorinations of alkenes were conducted on the 18VE PdIV complex. Positive solvent effects as well as kinetic measurements probing the impact of cyclohexene and chloride concentrations on the rate of alkene chlorination support a PdIV-Cl ionization in the first step. Product stereochemistry and product distributions from various alkenes also support Cl+-transfer from the pentacoordinated PdIV-intermediate LPdIVCl 3+ to olefins. 1-Hexene/3-hexene competition experiments rule out both the formation of π-complexes along the reaction coordinate as well as in situ generated Cl2 from a reductive elimination process. Instead, a ligand-mediated direct Cl+-transfer from LPd IVCl3+ to the π-system is likely to occur. Similarly, C-H bond chlorinations proceed via an electrophilic process with in situ formed LPdIVCl3+. The presence of a large excess of added Cl- slows cyclohexene chlorination while the presence of stoichiometric amounts of chloride accelerates both PdIV-Cl ionization and Cl+-transfer from LPdIVCl3 +. 1H NMR titrations, T1 relaxation time measurements, binding isotherms, and Job plot analysis point to the formation of a trifurcated Cl-...H-C bond in the NHC-ligand periphery as a supramolecular cause for the accelerated chemical events involving the metal center.
- McCall, A. Scott,Wang, Hongwang,Desper, John M.,Kraft, Stefan
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scheme or table
p. 1832 - 1848
(2011/04/15)
-
- Kinetics of methoxy-NNO-Azoxymethane hydrolysis in strong acids
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The kinetics of methoxy-NNO-azoxymethane (I) hydrolysis in concentrated solutions of strong acids (HBr, HCl, HClO4, and H2SO 4) has been investigated by a manometric method. The gas evolution rate is described by the equation corresponding to two consecutive first-order reactions, with the rate constant of the second reaction considerably exceeding the rate constant of the first reaction, i.e., k 2 {ie17-1} k 1. The temperature dependences of k 1 (s-1) in 47.59% HBr in the temperature range from 60 to 90°C and in 64.16% H 2SO4 between 80 and 130°C are described by Arrhenius equations with IogA= 12.7 ± 1.5 and 13.6 ± 1.4 and E a = 115 ± 10 and 137 ± 10 kJ/mol, respectively. The parameters of the Arrhenius equation for the rate constant k 2 for the reaction in 64.16% H2SO4 between 80 and 130°C are IogA= 9.1 ± 2.5 and E a = 91 ± 18 kJ/mol. An analysis of the UV spectra of compound I in concentrated H2SO4 shows that I is a weak base (pKBH+ ≈ - 6). The rate-determining step of the hydrolysis of I is the attack of the nucleophile on the carbon atom of the MeO group of the protonated molecule of I. The resulting methyldiazene dioxide decomposes via a complicated mechanism to evolve N2, NO, and N2O. The pseudo-first-order rate constant k 1 of the reaction at 80°C depends strongly on the acid concentration and on the type of nucleophile (Br-, Cl-, or H2O). The relationship between k 1 and the rate constant k of the bimolecular nucleophilic substitution reaction (SN2) is given by the linear equation log [k1/(CH + CNu)] = m ≠ mX 0 + log (k/KBH+), where CH + and C Nu are the concentrations of H+ and nucleophile, respectively; X 0 is the excess acidity; and m and m are coefficients. The Swain-Scott equation log (kNu/kH2 O) = ns, where n is the nucleophilicity factor and s is the substrate constant (s = 0.72), is applicable to the rate constants k of the S N2 reactions of the protonated molecule of I with Br-, Cl-, and H2O.
- Zyuzin,Lempert
-
experimental part
p. 17 - 25
(2011/05/14)
-
- Hydrodechlorination of chloromethanes with a highly stable Pt on activated carbon catalyst
-
A platinum catalyst with activated carbon-support (Pt/C) was prepared and showed a high activity for the deep gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) and chloroform (TCM), with conversions of up to 70% and 100%, respectively (operating conditions: atmospheric pressure, reaction temperatures of 150-250 °C, and space-times of 0.08-1.7 kg h mol -1). The catalyst was highly selective to methane (the only non-chlorinated product) with selectivities of up to 85% for HDC of DCM and 93% for HDC of TCM. The catalyst showed exceptional stability with no loss of activity after 26 days on stream in the HDC of DCM. This can be ascribed to its high resistance to poisoning by organic compounds compared to Pd/C catalysts previously studied. This can be attributed to re-dispersion of Pt during the reaction and to the high proportion of metal in the zero-valent state (Pt 0) which disfavors the stabilization of chlorocarbon compounds at the active centers of the catalyst.
- Alvarez-Montero,Gomez-Sainero,Mayoral,Diaz,Baker,Rodriguez
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body text
p. 389 - 396
(2011/06/17)
-
- PROCESS FOR PRODUCING METHYL CHLORIDE AND SULFUR DIOXIDE
-
Produce methyl chloride and sulfur dioxide using a reactor with lanthanum oxychloride, and contacting the lanthanum oxychloride with methanesulfonyl chloride under conditions sufficient to convert a portion of the methanesulfonyl chloride to methyl chloride and sulfur dioxide.
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-
Page/Page column 2; 3
(2011/10/03)
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- Synthetic routes to, transformations of, and rather surprising stabilities of (N-Methyl-N-phenylcarbamoyl)sulfenyl Chloride, ((N-Methyl-N-phenylcarbamoyl) dithio)carbonyl chloride, and related compounds
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(Figure presented) The title compound classes, (carbamoyl)sulfenyl chlorides and ((carbamoyl)dithio)carbonyl chlorides, have been implicated previously as unstable, albeit trappable, intermediates in organosulfur chemistry. The presentwork reports for each of these functional groups: (i) several routes to prepare it in the N-methylaniline family; (ii) its direct structural characterization by several spectroscopic techniques; (iii) its rather unexpected stability and its ultimate fatewhen it decomposes; (iv) a series of further chemical transformations that give highly stable derivatives, each in turn subject to thorough characterization. Relevant kinetic and mechanistic experiments were carried out, including some with p-methyl- and 2,6-dimethyl-substituted N-methylanilines. Given that the title compounds can be isolated and are relatively stable, they may find applications in the preparation of thiolyzable and/or photolabile protecting groups for the sulfhydryl function of cysteine and for the development of new protein synthesis and modification reagents
- Schrader, Alex M.,Schroll, Alayne L.,Barany, George
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experimental part
p. 7882 - 7892
(2011/12/14)
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- A new synthesis of cytotoxic thiosulfonates and the first synthesis of deuterated thiosulfonates
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A new synthesis of thiosulfonates starting from thiophenols and cyanuric chloride activated dimethyl sulfoxide is reported herein. Although the yields of the reactions are moderate, this method enables the incorporation of the SCD3 group of dimethyl sulfoxide-d6 into thiosulfonates. This is the first synthesis of deuterated thiosulfonates with a labeling purity above 99%. In addition, the cytotoxicity of the thiosulfonates is reported for the first time. Georg Thieme Verlag Stuttgart. New York.
- Gao, Feng,Zhai, Huiyuan,Jin, Meina,Chu, Guobiao,Duan, Hongquan,Li, Chunbao
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experimental part
p. 3635 - 3638
(2011/12/16)
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- The 2-indenylidene chloropalladate {PdCl[Ind(Ph2P=S) 2]}(n Bu4N): A versatile pincer complex with "innocent" and "noninnocent" behavior
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The chloropalladate pincer complex {PdCl[Ind(Ph2P=S) 2]}(nBu4N) (2) has been prepared, and its reactivity has been thoroughly investigated. Alkyl halides such as iodomethane and benzyl chloride react at the electron-rich 2-indenylidene moiety, leading to the 2-indenyl pincer complexes {PdI[Ind(Me)(Ph2P=S)2]} (3) and {PdCl[Ind(Bn)(Ph2P=S)2]} (4), respectively. The ligand backbone is also involved in the reaction of 2 with the electron-deficient alkyne MeCO2C≡CCO2Me. Formally, one of the pincer ligand side arms is elongated and the original complex 5, featuring three fused metallacycles, is obtained. Nucleophiles such as PPh3 and NHCy 2 also react readily with 2, to give the corresponding 2-indenylidene complexes by displacement of the chloride at Pd. In addition, treatment of 2 with PhC≡CLi affords {Pd(C≡CPh)[Ind(Ph2P=S) 2]}(nBu4N) (8), the first alkynylpalladate to be isolated. All the new compounds have been characterized by multinuclear NMR spectroscopy and mass spectrometry. The structures of complexes 3, 5, and 8 have been further analyzed by means of X-ray diffraction studies.
- Oulie, Pascal,Nebra, Noel,Ladeira, Sonia,Martin-Vaca, Blanca,Bourissou, Didier
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experimental part
p. 6416 - 6422
(2012/01/31)
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- Exceptionally high decarboxylation rate of a primary aliphatic acyloxy radical determined by radical product yield analysis and quantitative 1H-CIDNP spectroscopy
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Symmetrical (RCO2CO2R; R=XCH2CH 2) and asymmetrical (RCO2CO2R′; R=C 9H19CH2CH2, R′=CH3 or m-ClC6H4) primary diacyl peroxides were thermally decomposed under different conditions to analyze the decarboxylation rates of the thermally generated acyloxy radicals. Quantitative models of the geminate product yields, and qualitative and quantitative 1H-CIDNP spectroscopy were used to obtain the decarboxylation rate estimates. Results reported here suggest that, unlike short chain acyloxy radicals such as propanoyloxyl, long chain acyloxy radicals possess the highest decarboxylation rates of all known acyloxy radicals, estimated at (0.5-1.5)× 10 12s-1 between 80 and 140°C. Given the nature of the dissociative state of acyloxy radicals, such rates appear to be the result of destabilization of the former by the steric bulk of the long chain substituents. Additionally, the rate of this order of magnitude suggests a nearly concerted decarboxylation of primary diacyl peroxides. Copyright
- Fraind, Alicia,Turncliff, Ryan,Fox, Teri,Sodano, Justin,Ryzhkov, Lev R.
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scheme or table
p. 809 - 820
(2012/06/29)
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- OXIDATIVE MONO-HALOGENATION OF METHANE
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Oxidatively halogenate methane by placing a feedstream that comprises methane, a source of halogen, a source of oxygen and, optionally, a source of diluent gas in contact with a first catalyst (e.g. a solid super acid or a solid super base) that has greater selectivity to methyl halide and carbon monoxide than to methylene halide, trihalomethane or carbon tetrahalide. Improve overall selectivity to methyl halide by using a second catalyst that converts at least part of the feedstream to a mixture of methyl halide, methylene halide, trihalomethane, carbon tetrahalide and unreacted oxygen, and placing that mixture in contact with the first catalyst which converts at least a portion of the methylene halide, trihalomethane and carbon tetrahalide to carbon monoxide, hydrogen halide and water.
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Page/Page column 14-16
(2010/06/17)
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