- Atmospheric chemistry of hexafluorocyclobutene, octafluorocyclopentene, and hexafluoro-1,3-butadiene
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The relative rate method was used to measure k(Cl + hexafluorocyclobutene) = (8.88 ± 0.69) × 10-13, k(Cl + octafluorocyclopentene) = (1.02 ± 0.11) × 10-12, k(Cl + hexafluoro-1,3- butadiene) = (7.28 ± 0.99) × 10-11, k(OH + hexafluorocyclobutene) = (8.6 ± 1.6) × 10-14, k(OH + octafluorocyclopentene) = (1.01 ± 0.16) × 10-13, and k(OH + hexafluoro-1,3-butadiene) = (9.64 ± 1.76) × 10-12 cm3 molecule-1 s-1 in 700 Torr N2, or air, diluent at 295 K. The atmospheric lifetimes of hexafluorocyclobutene, octafluorocyclopentene, and hexafluoro-1,3-butadiene were estimated to be 135, 104, and 1.1 days, respectively. The 100 year time horizon global warming potentials for hexafluorocyclobutene and octafluorocyclopentene are 42 and 28.
- Wallington,Hurley
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- Direct Measurement of the Rate Constants in the Reaction of Nitrous Acid with Methanol
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Rate constants have been determined by stopped-flow spectrophotometry and mechanisms are deduced for the nitrosation of methanol by nitrous acid (and nitrosyl chloride in water) and for the reverse reaction, the hydrolysis (or denitrosation) of methyl nitrite.
- Aldred, S. Elaine,Williams, D. Lyn H.
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- Photodissociation of Methyl Nitrate in a Molecular Beam
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The photodissociation of methyl nitrate, CH3ONO2, has been investigated by photofragment translational spectroscopy.At the photolysis wavelength of 193 nm the predominant primary decay (ca. 70percent) involves the fission of the weak CH3O-NO2 bond (D10 ca. 41 kcal/mol) to yield CH3O + NO2 fragment pairs which show a bimodal translational energy distribution.The component consisting of the fast fragment pairs has an average translational energy (ET) = 41 kcal/mol and a recoil anistropy β = 0.9, while the slow component is characterized by (ET) = 19 kcal/mol and β = 0.A significant portion of the NO2 fragments of the slow component is subject to a unimolecular decay to NO + O(3P).An additional primary decay route leads to the formational of methyl nitrite, CH3ONO, and atomic oxygen O(1D) with (ET) = 6 kcal/mol and β = 1.2.This competing reaction requires fission of the strong N-O bond (D110 ca. 118 kcal/mol) and its occurrence indicates an initial localization of the photoexcitation on the NO2 moiety in the parent molecule.At higher laser fluence secondary photodissociation of the primary fragments CH3ONO was observed.Photolysis at 248 nm is shown to produce CH3O + NO2 fragment pairs exclusively, with (ET) = 17 kcal/mol.
- Yang, Xuefeng,Felder, Peter,Huber, J. Robert
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- Kinetic and mechanistic study of the pressure and temperature dependence of the reaction CH3O + NO
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New kinetic measurements for the CH3O + NO reaction have been performed using two different techniques. The discharge flow (DF) technique has been used to investigate the 0.5-5 Torr and 248-473 K pressure and temperature ranges and pulsed laser photolysis (PLP) has been used for the 30-500 Torr and 284-364 K ranges. These new results represent an extension of the pressure and temperature ranges investigated previously. This reaction is known to present two reaction pathways, the association pathway yielding CH3ONO and the disproportionation pathway yielding CH2O + HNO. Based on literature and present experimental data, using the results of ab initio calculations, a multichannel RRKM analysis was developed to interpret the experimental results. This analysis has shown that the disproportionation reaction occurs simultaneously by both a direct hydrogen abstraction reaction, and via the formation of energized CH3ONO* complex in competition with the association reaction. The RRKM analysis, fitted to present and previous data, has yielded a second-order limiting low-pressure value of 2.5 × 10-12 cm3 molecule-1 s-1 at 298 K, with a complex temperature dependence. The limiting high-pressure rate constant derived in the same way is k∞ = (3.4 ± 0.4) × 10-11(T/298)-0.75. The model allows the prediction of CH3O loss rate constants and of the branching ratios in the 1-760 Torr and 220-600 K ranges. For a convenient presentation of the overall rate constant, an analytical expression using the conventional Troe expression with a temperature-dependent addition constant, has been fitted to the results of the RRKM analysis.
- Caralp, Francoise,Rayez, Marie-Therese,Forst, Wendell,Gomez, Nathalie,Delcroix, Bruno,Fittschen, Christa,Devolder, Pascal
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- Kinetics of the reactions of OH radicals with selected acetates and other esters under simulated atmospheric conditions
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The relative hydroxyl reaction rate constants from the simulated atmospheric oxidation of selected acetates and other acetates and other esters have been measured. Reactions were carried out at 297 ± 2K in 100-liter FEP teflon-film bags. the OH radicals were generated from the photolysis of methyl nitrite in pure air. Using a rate constant of 2.63 × 10-11 cm3 molecule-1 s-1 for the reaction of OH radicals with propene, principal reference organic compound, the rate constants (×1012 cm3 molecule-1 s-1) obtained for the acetates and esters used in this study. A linear correlation was observed for a plot of the measured relative rate constants vs. the number of CH2 groups per molecule of the following acetates: methyl acetate, ethyl acetate, n-propyl acetate, butyl acetate and pentyl acetate.
- Williams,O'RJI,Stone
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- Low-energy Fragmentations of Five Isomeric +* Ions
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The low-energy fragmentation characteristics of the +* isomers +* (a), +* (b), +* (c), +* (d) and +* (e) were studied in detail by metastable ion mass spectrometry.In agreement with most earlier observations, appearance energy measurements established the potential energy surface of the isomers a, b and c, showing the intricate interrelations between them.It was concluded that a isomerizes into b prior to fragmentation by loss of *OH and H2O and into c before loss of *H and H3CO* moreover, the reversereactions do not take place on the metastable time-frame.The dominant metastable process for isomers d and e (obtained via HCN loss from glyoxime) was generation of +*.For isomer e this process was proposed to involved a rate-determining isomerization into d.It was concluded that isomers d and e do not intercommunicate with ions a, b and c prior to fragmentation.Neutralization-reionization mass spectrometry indicated that the enol form of formohydroxamic acid as well as the keto conterpart are stable in the gas phase.
- Sirois, M.,Holmes, J. L.,Hop, C. E. C. A.
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- Collisional Quenching of CH3O(A2A1)
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Room temperature rate constants for collisional quenching of CH3O(A2A1) have been measured for 20 collision partners.Methoxy radicals are produced by 248-nm photolysis of CH3ONO and the CH3O(A2A1) is produced by exciting the A-X transition using a pulsed dye laser.Rate constants are determined by monitoring the time-resolved fluorescence signal as a function of quenching gas pressure.The experimental quenching cross sections are best correlated in terms of the CH3O-collision partner interaction well depth.Reasonable correlation is observed for 15 quenching gases, but several exceptions are apparent.A similar trend in collision partner quenching efficiency for OH(A2Σ+) and CH3O(A2A1) is noted and discussed.
- Wantuck, Paul J.,Oldenborg, Richard C.,Baughcum, Steven L.,Winn, Kenneth R.
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- Atmospheric chemistry of cis-CF3CH=CHCl (HCFO-1233zd(Z)): Kinetics of the gas-phase reactions with Cl atoms, OH radicals, and O3
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FTIR smog chamber techniques were used to measure the rate coefficients k(Cl + cis-CF3CH=CHCl) = (6.26 ± 0.84) × 10-11, k(OH + cis-CF3CH=CHCl) = (8.45 ± 1.52) × 10-13, and k(O3 + cis-CF3CH=CHCl) = (1.53 ± 0.12) × 10-21 cm3 molecule-1 s-1. The atmospheric lifetime of cis-CF3CH=CHCl is determined by reaction with OH radicals and is estimated to be 14 days. The infrared spectrum of cis-CF3CH=CHCl was recorded and the integrated absorption over the range 600-2000 cm-1 was measured to be (1.48 ± 0.07) × 10-16 cm molecule-1. Accounting for non-uniform horizontal and vertical mixing leads to a GWP100 value of essentially zero. Correction to account for unwanted Cl atom chemistry in our previous relative rate study of the kinetics of the reaction of OH with trans-CF3CH=CHCl gives k(OH + trans-CF3CH=CHCl) = (3.61 ± 0.37) × 10-13 cm3 molecule-1 s-1.
- Andersen, Lene L?ffler,?sterstr?m, Freja From,Sulbaek Andersen, Mads P.,Nielsen, Ole John,Wallington, Timothy J.
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- Atmospheric chemistry of C2F5CH2OCH 3 (HFE-365mcf)
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FTIR smog chamber techniques were used to measure k(Cl + C 2F5CH2OCH3) = (2.52 ± 0.37) × 10-11 and k(OH + C2F5CH 2OCH3) = (5.78 ± 1.02) × 10-13 cm3 molecule-1 s-1 in 700 Torr of air diluent at 296 ± 1 K. The atmospheric lifetime of C2F 5CH2OCH3 is estimated to be 20 days. Reaction of chlorine atoms with C2F5CH2OCH3 proceeds 18 ± 2% at the -CH2- group and 82 ± 2% at the -CH3 group. Reaction of OH radicals with C2F 5CH2OCH3 proceeds 44 ± 5% at the -CH2- group and 56 ± 5% at the -CH3 group. The atmospheric fate of C2F5CH2OCH2O radicals is reaction with O2 to give C2F 5CH2OCHO. The atmospheric fate of C2F 5CH(O)OCH3 radicals is C-C bond-cleavage to give C 2F5 radicals and CH3OCHO (methyl formate). The infrared spectrum was recorded and used to estimate a global warming potential of 6 (100 year time horizon) for C2F5CH 2OCH3.
- Thomsen,Andersen,Nielsen,Wallington
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- Conformational kinetics of methyl nitrite. I. NMR spectral evidence for statistical intramolecular vibrational redistribution
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Pressure dependent rate constants for syn anti conformational exchange in gaseous methyl nitrite and in gaseous methyl nitrite-CO2 mixtures have been obtained from line shape analyses of 1H NMR spectra.The pressure dependence of the exchange rates is consistent with a specific reaction rate constant of ca. 1*109/s which agrees with RRKM calculations demonstrating that intramolecular vibrational redistribution is occurring at the statistical limit in methyl nitrite molecules with ca. 12 kcal/mol of internal vibrational energy.At 12 kcal/mol methyl nitrite has a state density of ca. 160/cm-1.These results indicate strong anharmonic and /or Coriolis coupling between vibrational levels.Bimolecular rate data for methyl nitrite and methyl nitrite-CO2 mixtures are consistent with a collisional efficiency βp for CO2 of 0.95(8) for activation of syn-anti conformational exchange at 258.8 K.
- Chauvel, J. Paul,Conboy, Claire B.,Chew, Wilbert M.,Matson, Gerald B.,Spring, Cheryl A.,et al.
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- Arrhenius parameters for the OH-initiated degradation of methyl crotonate, methyl-3,3-dimethyl acrylate, (: E)-ethyl tiglate and methyl-3-butenoate over the temperature range of 288-314 K
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The relative-rate technique has been employed to obtain rate coefficients for the reactions between the OH radical and four unsaturated esters (methyl crotonate (k1), methyl-3,3-dimethyl acrylate (k2), (E)-ethyl tiglate (k3) and methyl-3-butenoate (k4)) between 288 and 314 K in 760 Torr of synthetic air. The experiments were performed in a multiple-pass environmental chamber with in situ FTIR detection of the esters and reference compounds. The rate coefficients for the reactions displayed a negative dependence with temperature and low pre-exponential factors. The following Arrhenius expressions (in units of cm3 per molecule per s) were obtained: k1 = (3.39 ± 0.78) × 10-12exp[(750 ± 159)/T], k2 = (2.95 ± 0.63) × 10-12exp[(838 ± 182)/T], k3 = (1.49 ± 0.56) × 10-12exp[(522 ± 114)/T] and k4 = (1.90 ± 1.25) × 10-12exp[(834 ± 185)/T]. The kinetic results are in agreement with a mechanism involving mainly OH radical addition to the double with the reversible formation of an OH-adduct. Atmospheric implications are discussed with particular reference to the rate coefficients obtained as a function of the temperature.
- Colomer, Juan P.,Blanco, María B.,Pe?é?ory, Alicia B.,Barnes, Ian,Wiesen, Peter,Teruel, Mariano A.
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- RADICAL CATIONS OF ORGANIC NITRO-DERIVATIVES
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Attemps to generate the radical cations of nitroalkanes using the standard procedure of exposing dilute solutions in fluorotrichloromethane at 77 K to ionizing radiation gave low yields of the expected products, having a SOMO confined to oxygen as judged by their e.s.r. spectra, together with a species whose e.s.r. spectra closely resembles that of NO2 radicals.It is suggested that these are rearranged cations, .Similar treatment of nitrobenzene and a range of its ring-substituted derivatives gave initial electron loss from benzene ? orbitals, but on annealing these rearranged into radicals similar to those for the nitroalkanes.
- Ramakrishna, Rao,Symons, Martyn C. R.
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- Gas-phase degradation of 2-butanethiol initiated by OH radicals and Cl atoms: Kinetics, product yields and mechanism at 298 K and atmospheric pressure
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Relative rate coefficients and product distribution of the reaction of 2-butanethiol (2butSH) with OH radicals and Cl atoms were obtained at atmospheric pressure and 298 K. The experiments were performed in a 480 L borosilicate glass photoreactor in synthetic air coupled to a long path "in situ" FTIR spectrometer. The rate coefficients obtained by averaging the values from different experiments were: kOH = (2.58 ± 0.21) × 10-11 cm3 per molecule per s and kCl = (2.49 ± 0.19) × 10-10 cm3 per molecule per s. The kinetic values were compared with related alkyl thiols and homologous alkyl alcohols, where it was found that thiols react faster with both oxidants, OH radicals and Cl atoms. SO2 and 2-butanone were the major products identified for the reactions of 2-butanethiol with OH radicals and Cl atoms. The product yield of the reaction of 2-butanethiol and OH radicals were (81 ± 2)percent, and (42 ± 1)percent for SO2 and 2-butanone, respectively. For the reactions of 2-butanethiol with Cl atom, yields of SO2 and 2-butanone were (59 ± 2)percent and (39 ± 2)percent, respectively. A degradation mechanism was proposed for the pathways that leads to formation of identified products. The product distribution observed indicated that the H-atom of the S-H group abstraction channel is the main pathway for the reaction of OH radicals and Cl atoms with 2-butanethiol.
- Blanco, María B.,Cardona, Alejandro L.,Gibilisco, Rodrigo G.,Teruel, Mariano,Wiesen, Peter
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- Infrared matrix spectra, normal coordinate analysis and valence force field of six isotopomers of methyl nitrite
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Infrared-spectra of the isotopic species 13CH3ONO, CH318ONO, CH3O15NO and CH3ON18O, isolated in argon matrices, are reported.Spectral data together with earlier data on CH3ONO are used for derivation of 22 parameter harmonic valence force fields for both the cis and trans conformers and assignments are presented for all isotopic species in the two conformations.The valence force field will be used to propose assignments of cis and trans CD3ONO reported earlier by OGILVIE.A comparison of force constants of molecules with C-O, N-O, and N=O fragments and their dependence on conformation and structure is made.
- Ghosh, Pradip N.,Guenthard, Hs. H.
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- Investigation into the Kinetics and Mechanism of the Reaction of NO3 with CH3 and CH3O at 298 K between 0.6 and 8.5 Torr: Is there a Chain Decomposition Mechanism in Operation?
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The reactions CH3 + NO3 -> products (1), and CH3O + NO3 -> products (2), have been studied using a flow system at T = 298 K and at pressures between 0.6 and 8.5 Torr.The laser-induced fluorescence (LIF) technique was used to detect CH3O and multi-pass optical absorption to detect NO3.The chemical systems were studied as a pair of consecutive reactions; however, a simple analytical treatment was not sufficient to describe them because CH3O2 was formed as one of the products in the major channel of reaction (2).This species also reacts with NO3 regenerating CH3O.Use of a numerical model to correct for this regeneration process allowed rate parameters of k1 = (3.5 +/- 1.0)E-11 cm3 molecule-1 s-1 and k2 = (2.3 +/- 0.7)E-12 cm3 molecule-1 s-1 to be determined at 2.4 Torr.There is no pressure dependence observed for reaction (1) between 1 and 2.4 Torr, but the possibility of a slight pressure dependence for reaction (2) exists.These pressure effects are examined using the semi-empirical quantum RRK method.
- Biggs, Peter,Canosa-Mas, Carlos E.,Fracheboud, Jean-Marc,Shallcross, Dudley E.,Wayne, Richard P.
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- Formation of Methyl Nitrite and Methyl Nitrate during Plasma Treatment of Diesel Exhaust
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CH3ONO and CH3ONO2 were identified as products of the nonthermal plasma treatment of simulated diesel exhaust using FTIR spectroscopy. CH3ONO and CH3ONO2 were formed in the nonthermal plasma treatment of simulated diesel exhaust. The source of CH3ONOx was the association reaction of CH3O radicals with NOx. The source of CH3O radicals was oxidation of propylene, which produces CH3 radicals, which in turn, were oxidized to CH3O radicals. At 180°C, a significant fraction (60-85%1 of the CH3ONO decomposed upon flowing through the experimental apparatus. CH3ONO was formed during the passage of simulated diesel exhaust through a nonthermal plasma. If the plasma-treated exhaust is not passed over a catalyst, or if the catalyst is deactivated, CH3ONO will be emitted into the atmosphere. CH3ONO is not a desirable vehicle emission.
- Wallington,Hoard,Sulbaek Andersen,Hurley,Nakano,Kawasaki
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- 15N Isotope-selective infrared multiphoton dissociation of nitromethane by a free electron laser
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Successful experiments on the isotope-selective infrared multiphoton dissociation (IR MPD) of nitromethane molecules in the region of stretching vibrations of the NO2 group have been performed for the first time under IR free electron laser (FEL) irradiation in a mixture with the natural content of the 15N isotope of 0.4%. The content of the 15N isotope in the products of NO dissociation varies within 0.1-1.696 as a function of the laser radiation frequency.
- Petrov,Chesnokov,Gorelik,Straub,Szarmes,Madey
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- Preparation, Vapor Pressure, and Infrared Spectrum of Methyl Nitrite
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A convenient preparation of ordinary and deuterated methyl nitrite has been described, their high-resolution infrared spectra have been recorded, and the vapor-pressure curve of CH3ONO has been measured in the region 154 /= T(K) /=225: log P(torr) = -1365/T + 8.102.
- Rook, Frederick L.
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- Preparation, Properties and Crystal Structure of syn-Isomer of 2,6-Dichlorophenyl-cyanoxime, H(2,6-diCl-PhCO): Potent Carbonyl Reductase Inhibitor
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Abstract: The oximino(2,6-dichlorophenyl)acetonitrile, H(2,6-diCl-PhCO) has been synthesized in a reasonably high yield of 60%, and characterized using a variety of physical, electrochemical, spectroscopic methods and X-ray analysis. This compound belongs to the family of cyanoximes; a new subclass of oximes with the general formula NC–C(=N–OH)–R (where R is an electron-withdrawing group) which recently emerged as new biologically active compounds. This cyanoxime represents a disubstituted arylcyanoxime that was found to be a powerful inhibitor of the Carbonyl Reductase enzyme involved in the developing of resistance to anticancer treatment, and the making of cardiotoxic derivatives of anthracyclines that are currently used in medicine. The oximino(2,6-dichlorophenyl)acetonitrile, H(2,6-diCl-PhCO) is a weak acid with pKa = 6.17 and does not dissociate in organic polar protic and aprotic solvents. The cyanoxime was obtained as a microcrystalline mixture of two diastereomers (anti- and syn-) and deprotonates in solutions with the formation of yellow anions which exhibit solvatochromic behavior. However, one specific diastereomer—syn—was isolated in crystalline form from a solvent system as colorless blocks overlayed with pentane ether solution in a monoclinic system in a P2/c (#13) space group with unit cell parameters: a = 8.1720(2), b = 8.8013(3), c = 13.0146(4) and β = 102.546(3); Z = 4. A single crystal was studied using filtered CuKa radiation, providing Rint value of 0.0348 from a full-sphere of reflections. A crystal structure was solved using direct methods, and well refined to R1 = 0.0459, wR2 = 0.1268 and GOF = 1.107. The studied specimen of oximino(2,6-dichlorophenyl)acetonitrile, H(2,6-diCl-PhCO), represents a highly non-planar, rare syn-diastereomer in which the oxime fragment is positioned towards the chlorinated phenyl group. In the crystal, the compound forms a columnar structure extended along the c-direction by using slipped π–π stacking interactions. Columns are interconnected via H-bonding between the oxime OH-group and N atom of the nitrile group with the following parameters: N–H = 1.841??, and 169.20° N···H–O angle. No thermal interconversion of syn- into anti- diastereomer was observed upon heating of crystals of one isomer under flow of Ar. Graphic Abstract: [Figure not available: see fulltext.]
- Amankrah, Seth Adu,Charlier, Henry,Gerasimchuk, Nikolay,Hietsoi, Oleksandr,Tyukhtenko, Sergiy
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- PROCESS AND SYSTEM FOR PRODUCING ALKYL NITRITES
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A process for producing an alkyl nitrite is provided, comprising: mixing oxygen and a circulating gas in a pre-reactor, mixing the oxidized circulating gas and an alkyl alcohol liquid in a first esterification tower to generate alkyl nitrite, heating a portion of a first esterification tower bottom liquid in a circulating heating device external to the first esterification tower and transferring the heated collected first esterification tower bottom liquid into the first esterification tower, mixing a second portion of the collected first esterification tower bottom liquid and the circulating gas in a second esterification tower to generate alkyl nitrate, transferring a second esterification tower bottom liquid into an alkyl alcohol recycling tower. A related production system is also provided with a pre-reactor, a first esterification tower, a circulating heating device, a second esterification tower and an alkyl alcohol recycling tower.
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Page/Page column 9; 10; 11; 12
(2020/06/10)
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- METHOD AND APPARATUS FOR PRODUCING ALKYL NITRITE
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A method for producing an alkyl nitrite by bringing an aqueous solution containing nitric acid and an alkanol into contact with a gas including nitrogen monoxide and thereby producing an alkyl nitrite, in which the reaction temperature is 60° C. to 100° C., is provided.
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Paragraph 0075-0077
(2020/02/27)
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- Search for the shortest intermetallic Tl—Tl contacts: Synthesis and characterization of Thallium(I) coordination polymers with several mono- and bis-cyanoximes
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Five new Tl(I) coordination compounds based on aryl monocyanoximes, such as phenylcyanoxime – HPhCO, 1, 2-fluorophenylcyanoxime – H(2F-PhCO, 2, 3-fluorophenylcyanoxime – H(3F-PhCO), 3, of TlL composition, and aryl biscyanoximes, such as 1,3-cyanoxime (benzene) – H2(1,3-BCO, 4 and 1,4-cyanoxime (benzene) – H2(1,4-BCO), 5 of Tl2L stoichiometry were synthesized and characterized using spectroscopic methods, thermal stability studies, and X-ray analysis. All obtained complexes represent coordination polymers of different complexity, ranging in dimensionality from 1D in Tl(2F-PhCO) to 3D in Tl2(1,3-BCO). The most interesting feature of all synthesized complexes is the formation of Tl2O2 rhombs: non planar and non-centrosymmetric in Tl(PhCO), and planar and centrosymmetric in the other three compounds. These rhombi are interconnected, forming zigzag and ladder-type polymers in which very short thallophilic Tl—Tl distances were observed. Thus, in the structure of Tl2(1,3-BCO) the closest distance between metal centers was found to be 3.670 ?. This is the second shortest on-record intermetallic contact in non-organometallic and non-cluster, but Werner type complexes, and is close to that in metallic thallium: 3.456 ?. In all five new coordination polymers the central atom has a stereo-active 6 s2 lone pair that significantly distorts the shape of the coordination polyhedron of Tl(I). The first time, Tl–O vibrations in Tl2O2 rhombs were observed in Raman spectra of the obtained complexes. Thermal analysis studies evidenced stability of all complexes, but Tl(PhCO), to ~200 °C. The Tl2(1,3-BCO) compound demonstrates properties of the high energy compound, and violently exothermically decomposes at ~255 °C with the release of a significant amount of kinetic energy. The final product of anaerobic decomposition of all studied Tl-cyanoximates is metallic thallium sponge.
- Curtis, Scott,Lottes, Brett,Robertson, Daniel,Lindeman, Sergey V.,Gerasimchuk, Nikolay
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supporting information
(2020/04/08)
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- Thermal behavior of ammonium dinitramide and amine nitrate mixtures
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This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate exhibit low melting points and high-energy content, they represent potential liquid propellants for spacecraft. This study focused on the melting behavior and thermal-decomposition mechanisms in the condensed phase of ADN/amine nitrate mixtures during heating. We measured the melting point and exothermal behavior during constant-rate heating using differential scanning calorimetry and performed thermogravimetry–differential thermal analysis–mass spectrometry (TG–DTA–MS) to analyze the thermal behavior and evolved gases of ADN/amine nitrate mixtures during simultaneous heating to investigate their reaction mechanisms. Results showed that the melting point of ADN was significantly lowered upon the addition of amine nitrate with relatively low molecular volume and low melting point. TG–DTA–MS results showed that the onset temperature of the thermal decomposition of ADN/amine nitrates was similar to that of pure ADN. Furthermore, during thermal decomposition in the condensed phase, ADN produced highly acidic products that promoted exothermic reactions, and we observed the nitration and nitrosation of amines from the dissociation of amine nitrates.
- Matsunaga, Hiroki,Katoh, Katsumi,Habu, Hiroto,Noda, Masaru,Miyake, Atsumi
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p. 2677 - 2685
(2018/11/23)
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- Accessing the Nitromethane (CH3NO2) Potential Energy Surface in Methanol (CH3OH)-Nitrogen Monoxide (NO) Ices Exposed to Ionizing Radiation: An FTIR and PI-ReTOF-MS Investigation
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(D3-)Methanol-nitrogen monoxide (CH3OH/CD3OH-NO) ices were exposed to ionizing radiation to facilitate the eventual determination of the CH3NO2 potential energy surface (PES) in the condensed phase. R
- Góbi, Sándor,Crandall, Parker B.,Maksyutenko, Pavlo,F?rstel, Marko,Kaiser, Ralf I.
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p. 2329 - 2343
(2018/03/21)
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- Method for preparing alkyl nitrite by reaction between nitric oxide and nitric acid and alkyl alcohol
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The invention relates to a method for preparing alkyl nitrite by a reaction between nitric oxide and nitric acid and alkyl alcohol. The method comprises the step as follows: a gas-phase raw material containing nitric oxide and a liquid-phase raw material containing nitric acid and alkyl alcohol react in a trickle bed reactor so as to obtain alkyl nitrite. The method can be used for industrial production of synthesis gas preparation of glycol.
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Paragraph 0020; 0021; 0022; 0023; 0024; 0025; 0026-0031
(2017/08/28)
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- Methyl nitrite preparation method by reaction of NO and nitric acid and methanol
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The invention relates to a method for preparing methyl nitrite by a reaction of NO and nitric acid and methanol. By the method, the problems such as high supply cost of nitrogen oxide and severe equipment corrosion existing in present glycol preparation technology by synthesis gas are mainly solved. According to the technical scheme, a gas-phase raw material containing nitric oxide and a liquid-phase raw material containing nitric acid and methanol react in a trickle bed reactor to obtain methyl nitrite. By the technical scheme, the above problems are greatly solved. The method of the invention can be used for industrial production of methyl nitrite in the glycol preparation technology by synthesis gas.
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Paragraph 0039; 0040; 0041; 0042; 0043; 0044; 0045-0050
(2017/08/28)
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- A catalytic methanol reduction dilute nitric acid system method of nitrous acid methyl ester
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The invention discloses a method for preparing methyl nitrite by catalyzing methanol to reduce dilute nitric acid. The method comprises the following steps: by taking methanol as a reducing agent, under the action of catalysis of a carbon-based catalyst, reducing dilute nitric acid into nitrous acid at 30-100 DEG C, and esterifying nitrous acid and methanol, thereby preparing methyl nitrite. A fixed bed is adopted as a reactor, and nitrogen is taken as a carrier gas. The method is high in dilute nitric acid conversion efficiency, the prepared methyl nitrite is a gas, and raw material separation can be easily achieved.
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Paragraph 0017; 0018; 0019
(2017/01/02)
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- In situ DRIFTS study of CO coupling to dimethyl oxalate over structured Al-fiber@ns-AlOOH@Pd catalyst
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Pd-catalyzed CO coupling to dimethyl oxalate (DMO) process has been commercialized but its reaction mechanism is still open for debate between COCOOCH3? and COOCH3? (?, a surface site). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies were performed to clarify such controversy on a high-performance Al-fiber@ns-AlOOH@Pd catalyst. Intermediate species consisting of stretching vibrations of C[dbnd]O and C[sbnd]O, and rocking vibration of CH3 was indeed captured, which could be assigned to either COCOOCH3? or COOCH3?. To make discrimination between COCOOCH3? and COOCH3?, methyl oxalyl chloride (CH3OCOCOCl) and methyl chloroformate (CH3OCOCl) were employed to form COCOOCH3? and COOCH3? species on the catalyst surface for DRIFTS analyses. Interestingly, the characteristic bands of the as-observed intermediate species in the real reaction matched the obtained COCOOCH3? species from dissociative adsorption of CH3OCOCOCl. A double carbonylation reaction pathway was thus confirmed for the CO coupling to DMO, i.e., consecutive insertion of two CO molecules into OCH3? to form COCOOCH3? followed by combining OCH3? to yield DMO (CH3OCOCOOCH3).
- Wang, Chunzheng,Chen, Pengjing,Li, Yakun,Zhao, Guofeng,Liu, Ye,Lu, Yong
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p. 173 - 183
(2016/10/25)
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- A synthetic methyl nitrite system and method for synthesizing nitrous acid methyl ester
-
The invention discloses a methyl nitrite synthesis system. The system comprises a pre-reactor, a heat exchanger, a reaction rectification tower, a methanol recovery tower and a methanol recovery tank which are sequentially connected through a pipeline, wherein a circulating pump is arranged at the bottom of the methyl nitrite reaction rectification tower, the bottom of the methanol recovery tank is connected with the inlet of a methanol pump of the system through a pipeline, and the outlet of the methanol pump is connected with the sidewall of the methyl nitrite reaction rectification tower through a pipeline. The invention further discloses a methyl nitrite synthesis method which uses the methyl nitrite synthesis system. The method comprises the steps of carrying out oxidation reaction for 2-3 seconds in the pre-reactor so as to produce nitrogen trioxide, and carrying out esterification reaction with methanol in the reaction rectification tower so as to produce methyl nitrite. By adopting the methyl nitrite synthesis system and the methyl nitrite synthesis method, disclosed by the invention, the synthesis of clean methyl nitrite is guaranteed.
- -
-
Paragraph 0022-0032
(2017/06/24)
-
- Gas-phase reaction of methyl isothiocyanate and methyl isocyanate with hydroxyl radicals under static relative rate conditions
-
Gaseous methyl isothiocyanate (MITC), the principal breakdown product of the soil fumigant metam sodium (sodium N-methyldithiocarbamate), is an inhalation exposure concern to persons living near treated areas. Inhalation exposure also involves gaseous methyl isocyanate (MIC), a highly reactive and toxic transformation product of MITC. In this work, gas-phase hydroxyl (OH) radical reaction rate constants of MITC and MIC have been determined using a static relative rate technique under controlled laboratory conditions. The rate constants obtained are 15.36 × 10-12 cm3 molecule-1 s-1 for MITC and 3.62 × 10-12 cm3 molecule-1 s-1 for MIC. The average half-lives of MITC and MIC in the atmosphere are estimated to be 15.7 and 66.5 h, respectively. The molar conversion of MITC to MIC for OH radical reactions is 67% ± 8%, which indicates that MIC is the primary product of the MITC-OH reaction in the gas phase.
- Lu, Zhou,Hebert, Vincent R.,Miller, Glenn C.
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p. 1792 - 1795
(2014/03/21)
-
- Gas-phase reaction of methyl isothiocyanate and methyl isocyanate with hydroxyl radicals under static relative rate conditions
-
Gaseous methyl isothiocyanate (MITC), the principal breakdown product of the soil fumigant metam sodium (sodium N-methyldithiocarbamate), is an inhalation exposure concern to persons living near treated areas. Inhalation exposure also involves gaseous methyl isocyanate (MIC), a highly reactive and toxic transformation product of MITC. In this work, gas-phase hydroxyl (OH) radical reaction rate constants of MITC and MIC have been determined using a static relative rate technique under controlled laboratory conditions. The rate constants obtained are 15.36 × 10-12 cm3 molecule-1 s-1 for MITC and 3.62 × 10-12 cm3 molecule-1 s-1 for MIC. The average half-lives of MITC and MIC in the atmosphere are estimated to be 15.7 and 66.5 h, respectively. The molar conversion of MITC to MIC for OH radical reactions is 67% ± 8%, which indicates that MIC is the primary product of the MITC-OH reaction in the gas phase.
- Lu, Zhou,Hebert, Vincent R.,Miller, Glenn C.
-
p. 1792 - 1795
(2015/04/22)
-
- PROCESS OF PRODUCING OXALATE BY CO GAS PHASE METHOD
-
A process of producing oxalate by CO gas phase method includes the following steps: a) introducing nitrite salt, water and an inorganic acid first into a reactor I to produce a NO containing effluent I; and separating the resultant effluent to obtain the effluent II of NO; b) introducing the effluent II of NO, a C1-C4 alkanol and oxygen into a reactor II to be subjected to the reaction, and separating the resultant effluent to obtain the effluent IV of C1-C4 alkyl nitrites; c) introducing the effluent IV of C1-C4 alkyl nitrites and a CO gas stream into a coupling reactor where they are reacted to produce a NO containing effluent VI. The reactor I and/or the reactor II are preferably rotating supergravity reactors. Therefore, the process is applicable to the industrial production of oxalate by CO gas phase method.
- -
-
Paragraph 0032
(2013/04/10)
-
- Atmospheric chemistry of CF3CH2OCH3: Reaction with chlorine atoms and OH radicals, kinetics, degradation mechanism and global warming potential
-
FTIR smog chamber techniques were used to measure k(Cl + CF 3CH2OCH3) = (2.28 ± 0.44) × 10-11 and k(OH + CF3CH2OCH3) = (4.9 ± 1.3) × 10-13 cm3 molecule-1 s-1 in 700 Torr total pressure of air at 296 ± 2 K. The atmospheric lifetime of CF3CH2OCH3 is estimated at 25 days. Reaction of Cl atoms with CF3CH2OCH 3 proceeds 79 ± 4% at the CH3 group and 22 ± 2% at the CH2 group. Reaction with OH radicals proceeds 55 ± 5% at the CH3 group yielding CF3CH2OCHO and 45 ± 5% at the CH2 group yielding COF2 and CH 3OCHO as primary oxidation products. The infrared spectrum of CF 3CH(O)OCH3 was measured and a global warming potential GWP100 = 8 was estimated. The atmospheric chemistry and environmental impact of CF3CH2OCH3 is discussed in context of the use of hydrofluoroethers as CFC substitutes.
- ?sterstr?m, Freja From,Nielsen, Ole John,Sulbaek Andersen, Mads P.,Wallington, Timothy J.
-
body text
p. 32 - 37
(2012/03/09)
-
- Atmospheric chemistry of t-CF3CHCHCl: Products and mechanisms of the gas-phase reactions with chlorine atoms and hydroxyl radicals
-
FTIR-smog chamber techniques were used to study the products and mechanisms of the Cl atom and OH radical initiated oxidation of trans-3,3,3-trifluoro-1- chloro-propene, t-CF3CHCHCl, in 700 Torr of air or N 2/O2 diluent at 296 ± 2 K. The reactions of Cl atoms and OH radicals with t-CF3CHCHCl occur via addition to the CC double bond; chlorine atoms add 15 ± 5% at the terminal carbon and 85 ± 5% at the central carbon, OH radicals add approximately 40% at the terminal carbon and 60% at the central carbon. The major products in the Cl atom initiated oxidation of t-CF3CHCHCl were CF3CHClCHO and CF3C(O)CHCl2, minor products were CF3CHO, HCOCl and CF3COCl. The yields of CF3C(O)CHCl2, CF3CHClCOCl and CF3COCl increased at the expense of CF3CHO, HCOCl and CF3CHClCHO as the O2 partial pressure was increased over the range 10-700 Torr. Chemical activation plays a significant role in the fate of CF3CH(O)CHCl2 and CF 3CClHCHClO radicals. In addition to reaction with O2 to yield CF3COCl and HO2 the major competing fate of CF 3CHClO is Cl elimination to give CF3CHO (not C-C bond scission as previously thought). As part of this study k(Cl + CF 3C(O)CHCl2) = (2.3 ± 0.3) × 10-14 and k(Cl + CF3CHClCHO) = (7.5 ± 2.0) × 10-12 cm3 molecule-1 s-1 were determined using relative rate techniques. Reaction with OH radicals is the major atmospheric sink for t-CF3CHCHCl. Chlorine atom elimination giving the enol CF3CHCHOH appears to be the sole atmospheric fate of the CF 3CHCHClOH radicals. The yield of CF3COOH in the atmospheric oxidation of t-CF3CHCHCl will be negligible (3CHCHCl. the Owner Societies 2012.
- Andersen, M. P. Sulbaek,Nielsen,Hurley,Wallington
-
experimental part
p. 1735 - 1748
(2012/04/23)
-
- Part 1: Experimental and theoretical studies of 2-cyano-2-isonitroso-N- piperidynylacetamide (HPiPCO), 2-cyano-2-isonitroso-N-morpholylacetamide (HMCO) and their Pt- and Pd-complexes
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The reaction between substituted cyan-acetamides NC-CH2-C(O)X (X = N-piperidyne or N-morpholyl residues) and gaseous methylnitrite CH 3ONO in isopropanol at room temperature in the presence of a base within minutes leads to colorless cyanoximes 2-cyano-2-isonitroso-N- piperidynylacetamide (further as HPiPCO), and 2-cyano-2-isonitroso-N- morpholylacetamide (HMCO) in 70-90% yield. The deprotonation of HPiPCO and HMCO with a base such as NaOEt affords anionic Na-salts, bright-yellow in color originated from n → π* transitions in the nitroso-chromophore. Anionic cyanoximates react with aqueous solutions of K 2MCl4 (M = Pd, Pt) to form yellow-orange PdL2 and dark blue-green polymeric [PtL2]n (L = PiPCO -, MCO-), which upon treatment with DMSO or DMF breaks down to pale-yellow monomeric PtL2. Synthesized metal complexes were characterized by spectroscopic methods (IR, UV-Vis), measurement of the electric conductivity and the X-ray analysis. Both PdL2 and PtL2 exhibit non-electrolyte behavior in DMSO and DMF. Crystal structures of Pd(PiPCO)2 and Pt(PiPCO)2 were determined and revealed the formation of the cis-complexes with nearly planar geometry around the metal core and an adoption of the cis-anti configuration by anions, in contrast to the trans-anti geometry in structures of uncomplexed HPiPCO and HMCO. Ab initio calculations were performed for all six compounds: two cyanoxime ligands and four Pd and Pt metal complexes. A very satisfactory agreement between the calculated and experimental values of geometrical parameters of all evaluated compounds was attained. The electron densities, energies of HOMO and LUMO orbitals and molecular electrostatic potentials were calculated as well.
- Ratcliff, Jessica,Kuduk-Jaworska, Janina,Chojnacki, Henryk,Nemykin, Victor,Gerasimchuk, Nikolay
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experimental part
p. 1 - 11
(2012/05/20)
-
- Synthesis, Characterization, and studies of coordination-polymeres with isomeric pyridylcyanoximes: Route to metal ribbons with very short Tl???Tl separations
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Two isomeric pyridylcyanoximes, H(3PCO) and H(4PCO), containing nitrogen atoms of the heterocycle at 3- and 4-positions, respectively, were synthesized and thoroughly characterized using IR (including 15N labeling), UV-visible, 1H,13C one- and two-dimensional NMR spectroscopy, and X-ray analysis. The H(3PCO) exists as a mixture of syn- and anti-isomers in solutions, contrary to H(4PCO) which is present only as an anti-isomer. Both compounds have planar geometry in the solid state and form elegant zigzag chains via H-bonding between the oxime group and the N-atom of the heterocycle. The H(3PCO) and H(4PCO) upon addition of a base form colored conjugated and solvatochromic anions in solutions. The reaction of the hot aqueous solution of Tl2CO3 with solid isomeric pyridylcyanoximes leads to TlL, which were characterized by elemental analyses, IR spectroscopy, and X-ray analysis. Both complexes represent three-dimensional coordination polymers of different complexities where cyanoxime anions act as bridging ligands. Thallium(I) atoms in Tl(3PCO) and Tl(4PCO) form infinite, planar "metal ribbons" with unusually short intermetallic distances: 3.705 A in Tl(3PCO) and 3.635 A in Tl(4PCO) respectively, which are close to that in metallic thallium (3.465 A). The latter compound has the second shortest Tl???Tl thallophillic interaction reported in the literature thus far. Both yellow Tl(3PCO) and orange Tl(4PCO) are insulators at ambient conditions: R ~ 1 × 1011 Ohm.
- Marcano, Daniela,Gerasimchuk, Nikolay,Nemykin, Victor,Silchenko, Svitlana
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body text
p. 2877 - 2889
(2012/08/29)
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- Process for Producing C1-C4 Alkyl Nitrite
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A process of producing C1-C4 alkyl nitrite, comprising the following steps: a) firstly feeding nitrogen oxide and oxygen into Reactor I, contacting with an aluminosilicate catalyst, and reacting to produce an effluent I containing NO2 and unreacted NO; b) feeding the effluent I and C1-C4 alkanol into Reactor II, and reacting to produce an effluent II containing C1-C4 alkyl nitrite; and c) separating the effluent II containing C1-C4 alkyl nitrite to obtain C1-C4 alkyl nitrite; wherein reactor I is a fixed bed reactor, and Reactor II is a rotating high-gravity reactor; said nitrogen oxide in step a) is NO, or a mixed gas containing NO and one or more of N2O3 and NO2, wherein the molar number of NO is greater than that of NO2, if any; and the molar ratio of NO in nitrogen oxide to oxygen is 4-25:1.
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Page/Page column 5
(2011/10/31)
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- Process for Producing Cl-C4 Alkyl Nitrite
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The present invention relates to a process for producing C1-C4 alkyl nitrite, comprising loading a resin catalyst layer and/or a porous filler layer into a reactor, passing nitrogen oxide, oxygen and C1-C4 alkanol as raw materials through the resin catalyst layer and/or porous filler layer in a counter current, parallel current or cross current manner, reacting under the conditions including a reaction temperature of from 0 to 150° C., a reaction pressure of from ?0.09 to 1.5 MPa, a molar ratio of C1-C4 alkanol/nitrogen oxide of 1-100:1, a molar ratio of nitrogen oxide/oxygen of 4-50:1, to obtain an effluent containing C1-C4 alkyl nitrite, wherein said nitrogen oxide is NO, or a mixed gas containing NO and one or more selected from N2O3 and NO2.
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Page/Page column 4
(2011/10/31)
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- S-alkylation of thiacalixarenes: A long-neglected possibility in the calixarene family
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Despite the high nucleophilicity of sulfur atoms, thiacalixarenes have been alkylated only on oxygen atoms thus far. Using strong alkylating agents (triflates, trialkyloxonium salts), the substitution of the sulfur bridges has been successfully accomplished. The corresponding sulfonium salts of thiacalix[4]arene are formed regio- and stereoselectively as a completely new type of substitution pattern in thiacalixarene chemistry. These compounds possess interesting conformational behavior and could be used as unusual alkylating agents with uncommon selectivity.
- Kundrat, Ondrej,Eigner, Vaclav,Dvorakova, Hana,Lhotak, Pavel
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supporting information; scheme or table
p. 4032 - 4035
(2011/09/20)
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- Kinetics and mechanisms of OH-initiated oxidation of small unsaturated alcohols
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Smog chamber relative rate techniques were used to measure rate coefficients of (5.00 ± 0.54) × 10-11, (5.87 ± 0.63) × 10-11, and (6.49 ± 0.82) × 10 -11 cm3 molecule-1 s-1 in 700 Torr air at 296 ± 1 K for reactions of OH radicals with allyl alcohol, 1-buten-3-ol, and 2-methyl-3-buten-2-ol, respectively; the quoted uncertainties encompass the extremes of determinations using two different reference compounds. The OH-initiated oxidation of allyl alcohol in the presence of NOx gives glycolaldehyde in a molar yield of 0.85 ± 0.08; the quoted uncertainty is two standard deviations. Oxidation of 2-methyl-3-buten-2- ol gives acetone and glycolaldehyde in molar yields of 0.66 ± 0.06 and 0.56 ± 0.05, respectively. The reaction of OH radicals with allyl alcohol, 1-buten-3-ol, and 2-methyl-3-buten-2-ol proceeds predominately via addition to the >C=CH2 double bond with most of the addition occurring to the terminal carbon.
- Takahashi, Kenshi,Hurley, Michael D.,Wallington, Timothy J.
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experimental part
p. 151 - 158
(2010/05/18)
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- Atmospheric chemistry of i-butanol
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Smog chamber/FTIR techniques were used to determine rate constants of k(Cl + i-butanol) = (2.06 ± 0.40) × 10-10, k(Cl + i-butyraldehyde) = (1.37 ± 0.08) × 10-10, and k(OH + i-butanol) = (1.14 ± 0.17) × 10-11 cm3 molecule-1 s-1 in 700 Torr of N2/O2 diluent at 296 ± 2K. The UV irradiation of i-butanol/Cl 2/N2 mixtures gave i-butyraldehyde in a molar yield of 53 ± 3%. The chlorine atom initiated oxidation of i-butanol in the absence of NO gave i-butyraldehyde in a molar yield of 48 ± 3%. The chlorine atom initiated oxidation of i-butanol in the presence of NO gave (molar yields): i-butyraldehyde (46 ± 3%), acetone (35 ± 3%), and formaldehyde (49 ± 3%). The OH radical initiated oxidation of i-butanol in the presence of NO gave acetone in a yield of 61 ± 4%. The reaction of chlorine atoms with i-butanol proceeds 51 ± 5% via attack on the α-position to give an α-hydroxy alkyl radical that reacts with O2 to give i-butyraldehyde. The atmospheric fate of (CH3)2C(O)CH 2OH alkoxy radicals is decomposition to acetone and CH2OH radicals. The atmospheric fate of OCH2(CH3)CHCH 2OH alkoxy radicals is decomposition to formaldehyde and CH 3CHCH2OH radicals. The results are consistent with, and serve to validate, the mechanism that has been assumed in the estimation of the photochemical ozone creation potential of i-butanol.
- Andersen,Wallington,Nielsen
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experimental part
p. 12462 - 12469
(2011/02/28)
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- Vapor generation of inorganic anionic species after aqueous phase alkylation with trialkyloxonium tetrafluoroborates
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Aqueous phase reaction of trialkyloxonium tetrafluoroborates, R 3O+BF4- (R=Me, Et) has been tested in the alkylation of simple inorganic anionic substrates such as halogen ions, cyanide, thiocyanate, sulphide an
- D'Ulivo, Alessandro,Pagliano, Enea,Onor, Massimo,Pitzalis, Emanuela,Zamboni, Roberto
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experimental part
p. 6399 - 6406
(2010/04/06)
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- Atmospheric chemistry of CF3CF{double bond, long}CH2: Products and mechanisms of Cl atom and OH radical initiated oxidation
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The products of Cl atom and OH radical initiated oxidation of CF3CF{double bond, long}CH2 were studied in 700 Torr of N2/O2 diluent at 296 ± 1 K. The reactions of Cl atoms and OH radicals with CF3CF{double bond, long}CH2 proceed via electrophilic addition to the double bond. The reaction with chlorine atoms proceeds 56 ± 5% via addition to the central carbon. The chlorine atom initiated oxidation of CF3CF{double bond, long}CH2 gives CF3C(O)F in a molar yield which is indistinguishable from 100% and independent of [O2], and HC(O)Cl in a molar yield which increased from 30% to 59% as [O2] was increased from 3 to 700 Torr. The OH radical initiated oxidation of CF3CF{double bond, long}CH2 gives CF3C(O)F as major product in a yield of 91 ± 6%. The results are discussed with respect to the atmospheric chemistry and environmental impact of CF3CF{double bond, long}CH2.
- Hurley,Wallington,Javadi,Nielsen
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experimental part
p. 263 - 267
(2008/10/09)
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- The atmospheric oxidation of diethyl ether: Chemistry of the C 2H5-O-CH(O?)CH3 radical between 218 and 335 K
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The products of the Cl atom initiated oxidation of diethyl ether (DEE) were investigated at atmospheric pressure over a range of temperatures (218-335 K) and O2 partial pressures (50-700 Torr), both in the presence and absence of NOx. The major products observed at 298 K and below were ethyl formate and ethyl acetate, which accounted for ≈60-80% of the reacted diethyl ether. In general, the yield of ethyl formate increased with increasing temperature, with decreasing O2 partial pressure, and upon addition of NO to the reaction mixtures. The product yield data show that thermal decomposition reaction (3), CH3CH2-O-CH(O ?)CH3 → CH3CH2-O-CH=O + CH3, and reaction (6) with O2, CH3CH 2-O-CH(O?)CH3 + O2 → CH3CH2-O-C(=O)CH3 + HO2 are competing fates of the CH3CH2-O-CH(O?) CH3 radical, with a best estimate of k3/k6 ≈ 6.9 × 1024 exp(-3130/T). Thermal decomposition via C-H or C-O bond cleavage are at most minor contributors to the CH3CH 2-O-CH(O?)CH3 chemistry. The data also show that the CH3CH2-O-CH(O?)CH 3 radical is subject to a chemical activation effect. When produced from the exothermic reaction of the CH3CH2-O-CH(OO ?)CH3 radical with NO, prompt decomposition via both CH3- and probably H-elimination occur, with yields of about 40% and ≤15%, respectively. Finally, at temperatures slightly above ambient, evidence for a change in mechanism in the absence of NOx, possibly due to chemistry involving the peroxy radical CH3CH2-O-CH(OO ?)CH3, is presented. the Owner Societies.
- Orlando, John J.
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p. 4189 - 4199
(2008/09/19)
-
- BACTERICIDE COMPOSITION AND METHOD OF CONTROLLING PLANT DISEASE
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It is to provide a fungicidal composition having stable and high fungicidal effects against cultivated crops infected with plant diseases resulting from plant diseases. A fungicidal composition containing as active ingredients (a) a benzoylpyridine derivative represented by the formula (I) or its salt: (wherein X is a halogen atom, a nitro group, a substitutable hydrocarbon group, a substitutable alkoxy group, a substitutable aryloxy group, a substitutable cycloalkoxy group, a hydroxyl group, a substitutable alkylthio group, a cyano group, a carboxyl group which may be esterified or amidated, or a substitutable amino group, n is 1, 2, 3 or 4; R1 is a substitutable alkyl group, R2' is a substitutable alkyl group, a substitutable alkoxy group, a substitutable aryloxy group, a substitutable cycloalkoxy group or a hydroxyl group, p is 1, 2 or 3, and R2" is a substitutable alkoxy group or a hydroxyl group, provided that at least two of R2' and R2" may form a condensed ring containing an oxygen atom) and (b) at least one another fungicide.
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Page/Page column 20-21
(2008/06/13)
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- Ambident reactivity of the nitrite ion revisited
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(Chemical Equation Presented) Lost control: The rationalization of the ambident reactivity of NO2- by the change between charge control to orbital control has to be revised. SN1-type reactions of carbocations with NO2- give kinetically controlled product mixtures only when these reactions proceed without activation energy (diffusion control). Activation-controlled SN1 alkylations are reversible and lead to the thermodynamically more stable nitro compounds.
- Tishkov, Alexander A.,Schmidhammer, Uli,Roth, Stefan,Riedle, Eberhard,Mayr, Herbert
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p. 4623 - 4626
(2007/10/03)
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- Gas phase kinetics of the reaction system of 2NO2 ? N 2O4 and simple alcohols between 293-358 K
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The reversible reactions between nitrogen dioxide and alcohols (CH 3OH, CH3CH2OH, CH3CH 2CH2OH, CH3CHOHCH3) have been studied in the gas phase, using the spectrophotometric method. RONO (R = CH 3, CH3CH2, CH3CH2CH 2, CH3CHCH3) were identified by UV spectra. The equilibrium constants as well as the bimolecular rate constants were determined by computer modeling, using the programme MINICHEM. We calculated the following values for the forward rate constants k3av: (3.0±0.9)×10-18, (8.0±2.4)×10 -18, (5.4±1.6)×10-18, (2.0±0.6) ×10-18 cm3 molec-1 s-1 and the equilibrium constants Kav: 100±30, 40±12, 109±33, 39±12 at 298 K for the reactions with methanol, ethanol, 1-propanol and 2-propanol, respectively. The temperature dependence of the rate constants and the equilibrium constants were studied and it allowed to obtain the activation energy for the forward and for the reverse reaction, as well as thermochemical parameters. The equilibrium constants and the rate constants suggest that symmetrical N2O4 is the reactive species.
- Wojcik-Pastuszka,Gola,Ratajczak
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p. 1301 - 1313
(2007/10/03)
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- Oxime ester photoinitiators
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Compounds of the formulae I, II, III, IV and V wherein R1 i.a. is C4-C9cycloalkanoyl, C1-C12alkanoyl, C4-C6alkenoyl, or benzoyl; R2 is for example phenyl, C1-C20alkyl, C3-C8cycloalkyl, C2-C20alkanoyl, or benzoyl; Ar1 is R4S-phenyl or NR5R6-phenyl, each of which optionally is substituted; or Ar1 i.a. is optionally substituted; or Ar1 is naphthyl or anthracyl each of which is unsubstituted or substituted; or Ar1 is benzoyl, naphthalenecarbonyl, phenanthrenecarbonyl, anthracenecarbonyl or pyrenecarbonyl, each of which is unsubstituted or substituted, or Ar1 is 3,4,5-trimethoxyphenyl, phenoxyphenyl or biphenyl; Ar2 i.a. is optionally substituted, or naphthyl or anthracyl, each of which is unsubstituted or substituted, x is 2 or 3; M1 when x is 2, for example is phenylene, naphthalene, anthracylene, each of which optionally is substituted; M1, when x is 3, is a trivalent radical; M2 for example is M3 is for example C1-C12alkylene, cyclohexylene, or phenylene; n is 1-20; R3 is for example hydrogen or C1-C12alkyl; R3′ i.a. is C1-C12alkyl; substituted or —O-interrupted C2-C6alkyl; R4 is for example hydrogen, or C1-C12alkyl; and R5 and R6 independently of each other i.a. are hydrogen, C1-C12alkyl, or phenyl; are suitable as photoinitiators in particular in resist applications.
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Page/Page column 77-79
(2010/02/14)
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- Process for the arylation of olefins
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The present invention encompasses a process for preparing arylolefins by reacting one or more arylamines with one or more organic nitrites, in the presence of one or more olefins which bear at least one hydrogen atom on the double bond and in the presence of acid and in the presence of palladium or one or more palladium compounds.
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-
- Process for the preparation of aromatic or heteroaromatic sulphonyl chlorides
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Aromatic or heteroaromatic sulphonyl chlorides of the general formula I in which X may be a C or N, R1may be fluorine, chlorine, bromine, nitro, methoxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy, C1-C4alkyl or phenyl, R2may be H, fluorine, chlorine, bromine, OH, C1-C4alkyl, are prepared by diazotization of the compounds of the general formula II in which X, R1and R2are as defined for formula (I), and decomposition of the resulting diazonium salts in the presence of sulphur dioxide and a copper catalyst, where the compounds of the formula (II) are treated, in a mixture with one or more organic solvents, sulphur dioxide and a copper catalyst, with hydrogen chloride and alkyl nitrite at temperatures of from ?20 to +60° C.
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Page column 5
(2008/06/13)
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- Polyhalogen-substituted cinnamic acids and cinnamic acid derivatives and a process for the preparation of polyhalogen-substituted cinnamic acids and cinnamic acid derivatives
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Polyhalogenated cinnamic acids and cinnamic acid derivatives are prepared by reacting diazonium salts accessible from polyhalogenated anilines with acrylic acid or acrylic acid derivatives in the presence of a homogeneous, palladium-containing catalyst at about ?5 to about +100° C. Some of the cinnamic acids and cinnamic acid derivatives obtainable in this way are new. Cinnamic acids and cinnamic acid derivatives which can be prepared according to the invention can be used for the preparation of indanones which are precursors for agro- and pharmaceutical chemicals and for substances having liquid-crystalline properties.
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- Flow analysis method for determining the concentration of methanol and ethanol in the gas phase using the nitrite formation reaction
-
The emission sources of alcohols are significant from plants. The use of alcohol-fueled vehicles has increased. Due to the emission from these alcohol-fueled vehicles, the atmospheric alcohol concentrations are expected to be higher than that in the past from plant emission sources. A flow determination method for low molecular weight alcohols (methanol, ethanol) in the gas phase using the nitrite formation reaction, which was developed from an earlier method using a glass bottle was presented. The ambient air and NO2 (1000 ppm vol) were allowed to continuously flow in glass tube, which had been filled with 10 g of Pyrex glass beads. The flow rates of the ambient air and NO2 were 30 and 20 cc/min, respectively. The gas-phase alkyl nitrites produced by the dark reaction of atmospheric alcohols and NO2 on the Pyrex glass beads were analyzed by GC with an electron capture detector. The alcohol concentrations of the samples were computed using a calibrated conversion factor for each alcohol to its nitrite. The detection limits for the methanol and ethanol were 0.7 and 0.5 ppb vol, respectively. The method indicated significant improvement compared with the other methods for measuring ambient alcohol due to its high sensitivity, no required concentration process, and rather high yields of the alkyl nitrite from alcohol. It can be an automated analysis system for atmospheric alcohol.
- Takenaka,Nguyen,Bandow,Maeda
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p. 5847 - 5851
(2007/10/03)
-
- Synthesis and application of a novel coupling reagent, ethyl 1-hydroxy- 1H-1,2,3-triazole-4-carboxylate
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An optimal coupling reagent, ethyl 1-hydroxy-1H-1,2,3-triazole-4- carboxylate (HOCt), has been designed and synthesised for application to solid phase peptide synthesis using Fmoc chemistry. It is used in combination with carbodiimide reagents, has very high coupling efficiency, and does not absorb at 302nm, thus allowing real-time monitoring of each coupling cycle. Its applications in the synthesis of endothelin analogues and difficult sequences are also discussed.
- Jiang, Lu,Davison, Amanda,Tennant, George,Ramage, Robert
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p. 14233 - 14254
(2007/10/03)
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- Rate constants for the reactions of CH3O with CH2O, CH3CHO and i- C4H10
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The rate constants for the reactions of CH3O radicals with 3 reactants have been measured by two different techniques: laser photolysis (LP) and fast flow reactor (FF), both coupled with a detection of CH3O radicals by laser induced fluorescence. The reaction with formaldehyde CH2O has been measured in the temperature range 295 450 K. Both sets of results (LP and FF) are in excellent agreement and lead to a pressure independent rate constant of k1 = (1.1±0.3) x 10-12 exp(-9.6±1.0 kJ mol-1/ RT) cm3 s-1. The reaction with acetaldehyde CH3CHO has been measured between 286 and 493 K. Both sets of experiments are again in excellent agreement and lead to a pressure independent rate constant of k2 = (5.7±1.3) x 10-13 exp(- 5.2±0.7 kJ mol-1 / RT) cm3 s-1. No reaction could be detected with isobutane i-C4H10 at temperature up to 356 K, leading to an upper limit for k3 ≤ 2.5 x 10-15 cm3 s-1.
- Fittschen,Delcroix,Gomez,Devolder
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p. 2129 - 2142
(2007/10/03)
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- Atmospheric fate of several alkyl nitrates: Part 2. UV absorption cross-sections and photodissociation quantum yields
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The UV absorption cross-sections of methyl, ethyl and isopropyl nitrate between 233 and 340 nm have been measured using a diode array spectrometer in the temperature range 240-360 K. The absorption cross-sections of these alkyl nitrates decrease with increasing wavelength and decrease with decreasing temperature for λ > 280 nm. The photodissociation quantum yield for CH3ONO2 to produce NO2 and CH3O was found to be essentially unity at 248 nm using transient UV absorption methods. Production of O and H atoms in the photodissociation of methyl nitrate at 248 and 308 nm were found to be negligible using resonance fluorescence detection of the atoms. High quantum yields for O atoms were measured following 193 nm photolysis of methyl nitrate. The OH radical was measured to be a photoproduct with a very small quantum yield. Using the OH rate coefficients reported in the accompanying paper and the UV absorption cross-sections and the photodissociation quantum yields measured here, the first-order rate constants for atmospheric loss of methyl, ethyl and isopropyl nitrate were calculated. Photolysis was found to be the dominant atmospheric loss process for the three alkyl nitrates.
- Talukdar, Ranajit K.,Burkholder, James B.,Hunter, Martin,Gilles, Mary K.,Roberts, James M.,Ravishankara
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p. 2797 - 2805
(2007/10/03)
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- Photolysis of some N-nitroso- and N-nitro-anilines in solution
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The photolyses of three N-methyl-N-nitrosoanilines and two N-methyl-N-nitroanilines in organic solvents have been studied in the range of 300-340 nm. The influence of solvent character and the presence or absence of oxygen play important roles in the product composition range. The primary photochemical process involves N-N fission, this being homolytic in aprotic solvents and heterolytic in methanol. Three novel mechanistic conclusions are proposed, namely photosolvolysis of a nitrosamine in methanol, photooxidation of nitrosamines in aprotic solvents and the production of biphenyl derivatives on photolysis of nitro-substituted nitrosamines and nitramines in aromatic solvents.
- Gowenlock, Brian G.,Pfab, Josef,Young, Victor M.
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p. 915 - 919
(2007/10/03)
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- Temperature-dependent study of the CH3C(O)O2 + NO reaction
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The kinetics of the reaction between acetylperoxy radicals and nitric oxide have been examined both by transient IR absorption and by time-resolved UV spectroscopy. The former technique enables measurements of NO loss and NO2 formation, whereas the latter provides data on the decay of acetylperoxy radicals, the secondary formation of methylperoxy radicals, and their conversion into methylnitrite. The two methods give consistent rate constants which are fit by the expression k1 = (2.1-0.8+1.4) × 10-12e(570±140)/T cm3 s-1. The room temperature value of k1 = (1.4 ± 0.2) × 10-11 cm3 s-1 is somewhat smaller than the currently recommended value, which is based on indirect determinations of k1. Measurements of the CH3O2 and NO2 yields indicate that the reaction proceeds exclusively to the products CH3C(O)O and NO2. The negative temperature dependence suggests that the reaction proceeds via an intermediate adduct that rearranges and dissociates into the products.
- Maricq, M. Matti,Szente, Joseph J.
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p. 12380 - 12385
(2007/10/03)
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- Atmospheric chemistry of Di-tert-Butyl ether: Rates and products of the reactions with chlorine atoms, hydroxyl radicals, and nitrate radicals
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The rate constants for the gas-phase reactions of di-ferl-butyl ether (DTBE) with chlorine atoms, hydroxyl radicals, and nitrate radicals have been determined in relative rate experiments using FTIR spectroscopy Values of (DTBE→C1) = (1.4 ±0.2) × 10-10, K(DTBE+OH) = (3.7 ±0.7) × 10-12. and K(DTBE+NO3) = (2.8 ±0.9) × 10-16 cm3 molecule-11 s-1 were obtained. Tert-butyl acetate was identified as the major product of both Cl atom and OH radical initiated oxidation of DTBE in air in the presence of NO3 The molar tert-butyl acetate yield was 0.85 ±.0.11 in the Cl atom experiments and 0.84 ±0.11 in OH radical experiments As part of this work the rate constant for reaction of Cl atoms with terl-butyl acetate at 295 K was determined to be (1.6 ±0.3) × 10-11 cm3 molecule 1s-1. The stated errors are two standard deviations (2σ)
- Langer, Sarka,Ljungstroem, Evert,Waengberg, Ingvar,Wallington, Timothy J.,Hurley, Michael D.,Nielsen, Ole John
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p. 299 - 306
(2007/10/03)
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