- Dismutation of CFC-12 to CFC-13 over Chromia-Alumina Catalyst
-
Selective transformation of CCl2F2 (CFC-12) to fluorine-rich CClF3 (CFC-13) in the absence of HF over a chromia-alumina catalyst has been achieved.
- Venugopal, A.,Rao, K. S. Rama,Prased, P. S. Sai,Rao, P. Kanta
-
-
Read Online
- Photocatalysis of Chloroform Decomposition by Tetrachlorocuprate (II) on Dowex 2-X8
-
Heterogenized on a polystyrene anion exchange resin and in the presence of oxygen, CuCl24 catalyzes the photodecomposition of chloroform at wavelengths above 345 nm with greater efficiency than an equivalent amount in homogeneous solution. The reaction is proposed to proceed in two stages, the first stage yielding CCl4 and HO2 as products, the second consisting of a chain reaction resulting from the CuCl2 4-catalyzed photodissociation of CCl4, yielding phosgene with CCl3 radicals as chain carriers. Photodecomposition is retarded by added Cl, CH3CN, C6H12 or C2H5OH, which is ascribed to the displacement of CHCl3 molecules from the vicinity of the copper by attraction to the polystyrene matrix or to the alkylammonium cation sites.
- Harvey, Brent M.,Hoggard, Patrick E.
-
-
Read Online
- Kinetics and mechanism of the thermal chlorination of chloroform in the gas phase
-
The gas-phase thermal chlorination of CHCl3 has been studied up to high conversions by photometry and gas chromatography in a conditioned static quartz reaction vessel between 573 and 635 K. The initial pressures of both CHCl3 and Cl2 ranged from about 10-100 Torr, and the initial total pressure was varied between about 30-190 Torr. The reaction is rather complex because the produced CCl4 is not stable. The rate of consumption of Cl2 therefore increases in the course of time. This acceleration is explained quantitatively in terms of a radical mechanism and its kinetic and thermodynamic parameters. This reaction model is based on a known model for the pyrolysis of CCl4 to which only one reaction couple involving CHCl3 has been added. Analyses of the rates of the homogeneous elementary steps show that the primary source of Cl atoms is the second-order dissociation of Cl2, which is rapidly superseded by a secondary source, the first-order dissociation of the CCl4 primary product.
- Huybrechts,Hubin,Van Mele
-
-
Read Online
- A new strategy to improve catalytic activity for chlorinated volatile organic compounds oxidation over cobalt oxide: Introduction of strontium carbonate
-
Co3O4–SrCO3 catalysts with various Sr/Co ratios were synthesized by the coprecipitation method, and their properties were tuned by adjusting the Sr/Co molar ratio. Furthermore, the catalytic combustion of vinyl chloride (VC) was used to evaluate the catalytic activity of the Co3O4–SrCO3 catalysts. The physicochemical properties of the catalysts were studied by X-ray diffraction (XRD), infrared spectroscopy (IR), N2 sorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR) and VC temperature-programmed desorption (VC-TPD). The results showed that the Co3O4–SrCO3 catalysts exhibited composite phases of Co3O4 and SrCO3 and the presence of interactions between them. As a result, the crystallization of the Co3O4 phase for the Co3O4–SrCO3 catalysts was restrained, and the state of Co on the catalyst surface was adjusted. Furthermore, the reducibility and VC adsorption capacity of the Co3O4–SrCO3 catalysts with Sr/Co molar ratios of 0.2 and 0.4 were enhanced compared with those of the Co3O4 catalyst. Otherwise, catalyst SrCo-0.4 exhibited excellent catalytic performance, accompanied by the highest reaction rate and the lowest apparent activation energy. More importantly, the optimized SrCO3–Co3O4 catalyst showed superior catalytic performance compared with other transition metal oxides in previous literature. These results brought a new idea for promoting the activity of transition metal catalysts for the deep oxidation of chlorinated volatile organic compounds (CVOCs) by introducing alkaline-earth metal salts.
- Liu, Hao,Shen, Kai,Zhao, Hailin,Jiang, Yongjun,Guo, Yanglong,Guo, Yun,Wang, Li,Zhan, Wangcheng
-
-
Read Online
- Total Oxidation of Chlorinated Hydrocarbons by Copper and Chlorine based Catalysts
-
A new class of combustion catalyst containing copper and chlorine is described which has high activity for the total oxidation of chlorinated hydrocarbons such as CH2Cl2, CH2ClCH2Cl, CCl4 and 1,2-dichlorobenzene (1percent of gas stream) into carbon oxides, HCl and Cl2, in the presence of excess air at 300-500 deg C; no catalyst deactivation or loss of copper or chlorine is observed.
- Green, Malcolm L. H.,Lago, Rochel M.,Tsang, Shik Chi
-
-
Read Online
- The laser two-photon photolysis of liquid carbon tetrachloride
-
The two-photon photolysis of liquid CCl4 with 25 ps pulses of 266 nm light has been studied and compared with similar studies with high energy radiation. Both neutral and ionic species are produced from excited states and ionization. The emphasis of the study is on the ionic processes, while some data related to excited states and free radicals are presented. In both radiolysis and photolysis, a solvent separated charged pair, CCl3+ ∥ Cl-, exhibiting a λmax at 475 nm, is observed that exhibits a total growth over 38 to 100 ps. Solutes with ionization potentials less than that of CCl4 (11.47 eV) reduce the yield of the 475 nm species producing radical cations of the solute. The efficiency of this process is about 10-fold larger in radiolysis compared with photolysis. Analysis of the data suggest that the lower energy of two-photon photolysis produces a charge pair CCl4+ ∥ CCl4-, which decays in about 3 ps to CCl4+ ∥ Cl-. This species then decays to CCl3+ ∥ Cl-. The lifetime of the growth of the 475 nm is measured as 46 ps. These studies clearly show areas where radiolysis and photolysis can be quite similar and also areas where the vast difference in excitation energy introduces stark differences in the observed radiation and photoinduced chemistry.
- Zhang,Thomas
-
-
Read Online
- 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.
-
-
Read Online
- Kinetics of the R + Cl2 (R = CH2Cl, CHBrCl, CCl3 and CH3CCl2) reactions. An ab initio study of the transition states
-
The kinetics of the reactions of CH2Cl, CHBrCl, CCl3 and CH3CCl2 radicals with molecular chlorine were investigated in a heatable tubular reactor coupled to a photoionization mass spectrometer. The reactions were studied under pseudo-first-order conditions. The radicals were photogenerated at 248 nm. The pressure-independent rate constants determined were fitted to the following Kooij and Arrhenius expressions (units in cm3 molecule-1 s-1): k-(CH2Cl) = 7.56 × 10-17(T)1.45 exp(-350 J mol-1/RT), k(CHBrCl) = 5.83 × 10-20(T)2.3 exp(-300 J mol-1/RT), k(CCl3) = (8.4 ± 2.9) × 10-13 exp[-(25 ± 9) kJ mol-1/RT] and k(CH3CCl2) = 1.10 × 10-26(T)4.3 exp(+15000 J mol-1/RT). The Arrhenius rate expression for the Cl + CCl4 reaction was determined to be k(Cl + CCl4) = (3.9 ± 3.2) × 10-13 exp[-(71 ± 9) kJ mol-1/RT] using the kinetics measured and the thermochemistry of the CCl3 radical. Errors for the Kooij expressions were estimated to be 25% overall, and for the Arrhenius expressions they were calculated to be 1σ + Student's t values. The transition states of the measured R + Cl2 and four other similar reactions were localized and fully optimized at the MP2/6-31G(d,p) level of theory by ab initio methods. The energetics of the reactions were considered by determining thermochemical and activation parameters of the reactions. The reactivity differences of the radicals studied were explained by a free-energy correlation using an electronegativity difference scale.
- Seetula, Jorma A.
-
-
Read Online
- Aluminium(III) Chloride-Chlorohydrocarbon Chemistry. Fourier Transform Infra-red Spectroscopic Studies of the Reactions between Solid Aluminium(III) Chloride and 1,1,1-Trichloroethane or 1,1-Dichloroethene Vapours
-
The reactions of 1,1,1-trichloroethane and 1,1-dichloroethene vapours with solid aluminium(III) chloride have been studied using Fourier-transform i.r. spectroscopy to determine stoicheiometries as a function of time.Dehydrochlorination of 1,1,1-trichloroethane to give 1,1-dichloroethene and hydrogen chloride appears to be the only important process in the initial stage of the reaction, but the 1,1-dichloroethene formed reacts with the solid phase and the main product is a mixture of involatile chlorohydrocarbon species.The quantity of hydrogen chloride evolved indicates that the involatile material is highly unsaturated and in both reactions AlCl3 becomes progressively coated with a strongly purple-coloured tar.Small quantities of carbon tetrachloride are also produced in both reactions.
- McBeth, David G.,Winfield, John M.,Cook, Bernard W.,Winterton, Neil
-
-
Read Online
- A process of preparing methyl chloride using multistage reaction
-
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
- -
-
Paragraph 0092-0100; 0112; 0120
(2020/06/10)
-
- PRODUCTION OF CARBON TETRACHLORIDE FROM NATURAL GAS
-
The present invention provides processes to prepare carbon tetrachloride by the chlorination of natural gas in the presence of a diluent.
- -
-
Paragraph 0058
(2020/07/07)
-
- Nitrogen-Doped Carbon-Assisted One-pot Tandem Reaction for Vinyl Chloride Production via Ethylene Oxychlorination
-
A bifunctional catalyst comprising CuCl2/Al2O3 and nitrogen-doped carbon was developed for an efficient one-pot ethylene oxychlorination process to produce vinyl chloride monomer (VCM) up to 76 % yield at 250 °C and under ambient pressure, which is higher than the conventional industrial two-step process (≈50 %) in a single pass. In the second bed, active sites containing N-functional groups on the metal-free N-doped carbon catalyzed both ethylene oxychlorination and ethylene dichloride (EDC) dehydrochlorination under the mild conditions. Benefitting from the bifunctionality of the N-doped carbon, VCM formation was intensified by the surface Cl*-looping of EDC dehydrochlorination and ethylene oxychlorination. Both reactions were enhanced by in situ consumption of surface Cl* by oxychlorination, in which Cl* was generated by EDC dehydrochlorination. This work offers a promising alternative pathway to VCM production via ethylene oxychlorination at mild conditions through a single pass reactor.
- Chen, De,Chen, Qingjun,Fuglerud, Terje,Ma, Guoyan,Ma, Hongfei,Qi, Yanying,Rout, Kumar R.,Wang, Yalan
-
supporting information
p. 22080 - 22085
(2020/10/02)
-
- METHOD OF CONVERTING ALKANES TO ALCOHOLS, OLEFINS AND AROMATICS
-
A cost-effective and energy-efficient process is disclosed for converting a methane-containing gas to a methane sulfonyl halide comprising reacting the methane-containing gas, under illumination by a light emitting diode (LED) source, with a sulfuryl halide or a halogen in the presence of sulfur dioxide, whereby the methane sulfonyl halide is obtained for isolation or further reactions. The further reactions may sequentially include, in order, contacting the methane sulfonyl halide with a catalyst complex to form a methane monohalide; catalytically converting the methane monohalide to a value-added chemical such as an alcohol, an olefin, an aromatic, derivatives thereof, or mixtures thereof; releasing any hydrogen halide formed in the process; and converting the hydrogen halide to a halogen and recycling it for re-use.
- -
-
Paragraph 0054-0055
(2019/08/08)
-
- Method for synthesizing chloro-2, 2-di (perfluoro substituent)-1, 3-dioxolane compound
-
The invention discloses a method for synthesizing chloro-2, 2-di (perfluoroalkyl)-1, 3-dioxolane. The method comprises the following steps: mixing 2, 2-di (perfluoroalkyl)-1, 3-dioxolane liquid with acatalyst, introducing chlorine gas, heating to the temperature of 100-200 DEG C, and carrying out chlorination reaction to obtain 4, 4, 5, 5-tetrachloro-2, 2-di (perfluoro substituent)-1, 3-dioxolane. The perfluoroalkyl is independently selected from C1-4 perfluoroalkyls or fluorine atoms. According to the method, liquid-phase chlorination reaction is adopted, the reaction temperature is effectively reduced, the activity of the catalyst in the reaction is high, the side reaction is relieved, the requirements on equipment are reduced, the method is safe and simple to operate, the quality stability of the obtained product is high, and the industrial application feasibility is high.
- -
-
Paragraph 0049-0050
(2019/07/29)
-
- A CHLORINOLYSIS PROCESS FOR PRODUCING CARBON TETRACHLORIDE
-
A chlorinolysis process for producing carbon tetrachloride comprising providing a chlorination zone at an operating temperature of from 400 to 600°C with i) chlorine, ii) a C1 chlorinated compound comprising 1 to 3 chlorine atoms and iii) a carbon/second chlorine source to produce a reaction mixture, and, after a residence time, extracting a product mixture from the chlorination zone, the product mixture comprising carbon tetrachloride and optionally perchloroethylene, wherein the product mixture comprises a higher molar content of carbon tetrachloride than perchloroethylene, if present.
- -
-
Page/Page column 32-34
(2018/03/25)
-
- Low-temperature catalytic oxidation of vinyl chloride over Ru modified Co3O4 catalysts
-
Ruthenium modified cobalt oxides were prepared by (1) impregnating ruthenium chloride hydrate on cobalt oxides, Ru-supported catalysts (Ru/Co3O4), and (2) Ru-doped catalysts (Ru-Co3O4) where the ruthenium ions were added to the precursor solution, by a one-step sol-gel method with cobalt nitrate. The physicochemical properties of the catalysts were characterized by ICP, BET, XRD, HR-TEM, TPR, and XPS analysis. The effects of ruthenium were studied for the total oxidation of vinyl chloride. This Ru modifier was observed to enhance oxygenate formation. The different preparation methods made contributions to the different amounts of Ru4+ on the surfaces of the catalysts while Ru4+ would be in synergy with Co2+ concentration, and this also changed the chemical coordination of oxygen on the surface. Dispersion of Ru oxides on the cobalt oxides surface could not only improve the catalytic activity and stability on steam, but also decrease the amount of chlorinated by-products and increase HCl selectivity.
- Wang, Chao,Zhang, Chuanhui,Hua, Wenchao,Guo, Yanglong,Lu, Guanzhong,Gil, Sonia,Giroir-Fendler, Anne
-
p. 99577 - 99585
(2016/11/02)
-
- MANUFACTURING METHOD OF 1,1,1-TRICHLORO-3,3,3-TRIFLUOROPROPANE
-
PROBLEM TO BE SOLVED: To provide an efficient manufacturing method of 1,1,1-trichloro-3,3,3-trifluoropropane (HCFC-233fb) with high safety. SOLUTION: There is provided a manufacturing method of HCFC-233fb by contacting trichlorofluoromethane and 1,1-difluoroethylene in a presence of a catalyst. Preferably there is provided a manufacturing method of HCFC-233fb where the catalyst is a Lewis acid catalyst. More preferably there is provided a manufacturing method of HCFC-233fb where the Lewis acid catalyst is halide or halogenated oxide of at least one element selected from B, Al, Ga, In, Fe, Ni, Co, Sb, Nb, Sn, Ti, Zr, Hf, W and Ta. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
- -
-
Paragraph 0011; 0046-0048; 0054
(2017/03/28)
-
- PROCESS FOR THE PRODUCTION OF TETRACHLOROMETHANE
-
Processes for the production of tetrachloromethane are provided. The present processes involve catalyzing the chlorination of a feedstream comprising partially chlorinated methanes with a free radical initiator. Cost savings are thus provided relative to conventional processes that require the use of high temperatures and/or pressures, and safety concerns are alleviated or eliminated.
- -
-
Paragraph 0041-0042
(2013/07/05)
-
- Photocatalysis of chloroform decomposition by the hexachlororuthenate(IV) ion
-
Dissolved hexachlororuthenate(IV) effectively catalyzes the photodecomposition of chloroform to hydrogen chloride and phosgene under near-UV (λ > 345 nm) irradiation, whereby RuCl62- is not itself photocatalytically active, but is photochemically transformed into a species that is active, possibly RuCl5(CHCl3)-. Conversion to a photoactive species during irradiation is consistent with the acceleration of the decomposition rate during the early stages and with the apparent inverse dependence of the decomposition rate on the initial concentration of RuCl62-. The displacement of Cl - by CHCl3 in the coordination sphere to create the photoactive species is consistent with the retardation of photodecomposition by both Cl- and H2O. The much smaller photodecomposition rate in CDCl3 suggests that C-H bond dissociation occurs during the primary photochemical event, which is also consistent with the presence of a CHCl3 molecule in the first coordination sphere. In the presence of RuCl62-, chloroform decomposes under near-UV irradiation to phosgene and hydrogen chloride. The photoactive species is suggested to be RuCl5(CHCl3) -.
- Chan, Alissa M.,Pena, Laura A.,Segura, Rosa E.,Auroprem, Ramya,Harvey, Brent M.,Brooke, Caroline M.,Hoggard, Patrick E.
-
p. 274 - 279
(2013/07/31)
-
- Solvent-free and safe process for the quantitative production of phosgene from triphosgene by deactivated imino-based catalysts
-
Phosgene is quantitatively formed from solid triphosgene in a solvent-free and safe process without any reaction heat, catalyzed by planar N-heterocycles with deactivated imino functions. The rate of phosgene generation is adjustable to the rate of phosgene consumption in the subsequent phosgenation reaction by thermal control, catalyst concentration, and in some cases, specific properties of selected metal phthalocyanines. A thermal runaway reaction of this process is impossible.
- Eckert, Heiner,Auerweck, Johann
-
experimental part
p. 1501 - 1505
(2011/10/01)
-
- PROCESSES FOR THE SYNTHESIS OF 3-CHLOROPERFLUORO-2-PENTENE, OCTAFLUORO-2-PENTYNE, AND 1,1,1,4,4,5,5,5-OCTAFLUORO-2-PENTENE
-
Disclosed is a process comprising reacting CF3CF2CCI2CF2CF3 (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2CCI=CFCF3 (CFC-1419myx). Also disclosed herein is a process comprising reacting CF3CF2CCI=CFCF3 (CFC- 1419myx) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2C≡CCF3 (octafluoro-2-pentyne). Also disclosed herein is a process comprising reacting CF3CF2CCI2CF2CF3 (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2C≡CCF3 (octafluoro-2-pentyne). In addition, a process for reacting CF3CF2C≡CCF3, in a pressure vessel, with a Lindlar catalyst and hydrogen to produce CF3CF2CH=CHCF3 (1,1,1,4,4,5,5,5-octafluoro-2- pentene) is disclosed.
- -
-
Page/Page column 14
(2009/07/18)
-
- PROCESS FOR PRODUCING FLUORINE-CONTAINING COMPOUND BY REARRANGEMENT REACTION
-
The present invention provides a process for producing a compound represented by general formula (I): wherein X, Y and Z are same or different, and each represent H, F, Cl or an alkyl group, provided that the alkyl group and F are each not more than one; the process comprising contacting a fluorine-containing compound represented by general formula (II): wherein X, Y and Z are as defined above, with a Lewis acid catalyst to cause a chlorine rearrangement reaction. The present invention provides a novel reaction step, which can be used in the production process of a compound represented by the chemical formula CF3CF=CH2.
- -
-
Page/Page column 12
(2009/12/28)
-
- PROCESSES FOR PRODUCING AND COMPOSITIONS COMPRISING 2,3,3,3-TETRAFLUOROPROPENE AND/OR 1,2,3,3-TETRAFLUOROPROPENE
-
A process is disclosed for making CF3CF=CH2 or mixtures thereof with CHF=CFCHF2. The process involves contacting CCI3CF2CF3 and optionally CCI2FCF2CCIF2 with H2 in the presence of a catalyst including a catalytically effective amount of palladium supported on a support of alumina, fluorided aluminaand/or aluminum fluoride, to produce a product mixture including CH2=CFCF3 (and when CCI2FCF2CCIF2 is present, CHF=CFCHF2); recovering CH2=CFCF3 or a mixture thereof with CHF=CFCHF2 from the product mixture; and optionally, separating at least a portion of any CHF=CFCHF2 in the product mixture from the CH2=CFCF3 in the product mixture. The mole ratio of H2 to the total of CCI3CF2CF3 and CCI2FCF2CCIF2 fed to the reaction zone is between about 1 :1 and about 5:1. The present invention also provides another process for making CH2=CFCF3 Or mixtures thereof with CHF=CFCHF2 This process involves (a) reacting CCI3CF2CF3 and optionally CCI2FCF2CCIF2 with H2 in the presence of a catalytically effective amount of a hydrogenation catalyst to form CH3CF2CF3 (and when CCI2FCF2CCIF2 is present, CH2FCF2CHF2); (b) dehydrofluorinating CH3CF2CF3 and optionally any CH2FCF2CHF2 from (a) to form a product mixture including CH2=CFCF3, and if CH2FCF2CHF2 is present, CHF=CFCHF2; (c) recovering CH2=CFCF3 or a mixture thereof with CHF=CFCHF2 from the product mixture formed in (b); and optionally (d) separating at least a portion of any CHF=CFCHF2 in the product mixture formed in (b) from the CH2=CFCF3 in the product mixture formed in (b). The present invention also provides compositions involving CH2=CFCF3 and/or CHF=CFCHF2, including compositions useful as refrigerants, foam blowing agents, cleaning agents and aerosols and azeotropic compositions involving (a) CF2HCF=CFH and (b) HF.
- -
-
Page/Page column 17
(2008/12/05)
-
- Method for reusing heavy end by-products in the manufacture of polychlorinated alkanes
-
A method for recovering much of the carbon and chlorine value in the heavy ends and other undesired by-products formed during the production of a C3 or higher polychlorinated alkane through the reaction of carbon tetrachloride with an olefine or chlorinated olefine, the improvement comprising the step of first separating the heavy ends and any other higher or lower boiling chlorohydrocarbon impurities from most of the desired product, and subjecting the separated heavy ends and impurities therewith to a high temperature exhaustive chlorination to produce carbon tetrachloride, tetrachloroethene, and minor amounts of hexachlorobutadiene and hexachlorobenzene by-products.
- -
-
Page/Page column 3
(2008/06/13)
-
- Decomposition of dichlorodifluoromethane with simultaneous halogen fixation by vanadium oxide supported on magnesium oxide
-
Dichlorodifluoromethane (CCl2F2, 1% in He) decomposition with simultaneous halogen fixation by vanadium oxide supported on magnesium oxide was studied at 723 K in a flow apparatus. The pretreatment condition and vanadium loading of supported vanadium oxide samples affected the CCl2F2 decomposition efficiency. Through characterization studies (XRD, IR, Raman, and XPS) and reference experiments, Mg 3(VO4)2 was revealed to be the active species to initiate CCl2F2 decomposition, leading to MgF 2, MgCl2, and CO2 formation. The model experiments also suggested a detailed mechanism that VOCl3 was formed from Mg3(VO4)2 by a reaction with CCl 2F2 or the major intermediate compound CCl4, and that VOCl3 reacted with MgO to regenerate Mg3(VO 4)2 and to promote chlorine fixation as MgCl2.
- Tamai, Tsukasa,Inazu, Koji,Aika, Ken-Ichi
-
p. 1565 - 1574
(2007/10/03)
-
- Enhanced dichlorodifluoromethane decomposition with selective fluorine absorption by acidic fluoriated magnesinm oxide
-
CCl2F2 decomposition with simultaneous halogen absorption by partially fluorinated MgO (MgF2-MgO) was studied, focusing on the effects of the acidity of the surface. CCl2F 2 decomposition by MgF2-MgO was greatly promoted by fluorination of MgO at 10 mol% or higher. CCl2F2 decomposition was not a catalytic process over MgF2-MgO but basically a selective fluorine absorption reaction with MgO to form MgF2. Chlorine was released in the form of CCl4 regardless of reaction temperature and degree of fluorination of MgO due to low reactivity to CCl 4. NH3-TPD and pyridine adsorption experiments were carried out to characterize the acid sites on MgF2-MgO samples. The amount of acid sites became maximum for 10% MgF2-MgO and the strength of acid sites increased as fluorination proceeded. CCl2F2 decomposition was revealed to be initiated by Lewis acid sites on MgF 2-MgO formed by CCl2F2 decomposition as well as by fluorination with hydrofluoric acid aqueous solution. Thus, formation of the Lewis acid sites was considered to be the key step for efficient CCl 2F2 decomposition with selective fluorine absorption.
- Tamai, Tsukasa,Inazu, Koji,Aika, Ken-Ichi
-
p. 1239 - 1247
(2007/10/03)
-
- Method for photochemical sulfochlorination of gaseous alkanes
-
The invention concerns a method for making an alkanesulponyl chloride by photochemical reaction of an alkane with chlorine and sulphur dioxide, which consists in using as light source an indium-doped medium-pressure mercury lamp.
- -
-
-
- Decomposition of dichlorodifluoromethane with simultaneous halogen fixation by transition metal oxides supported on magnesium oxide
-
CFC12 (CCl2F2) decomposition with simultaneous halogen fixation by MgO was significantly promoted by supporting transition metal oxides. Vanadium oxides were the most effective and over 80% of halogen was fixed as magnesium halides i
- Tamai, Tsukasa,Inazu, Koji,Aika, Ken-Ichi
-
p. 436 - 437
(2007/10/03)
-
- Behavior of By-products during Direct-photodegradation Treatment of Trichloroethylene. Effect of Oxygen Concentration on Production of By-products
-
During direct-photodegradation treatment of trichloroethylene by a low-pressure mercury lamp in a dry air atmosphere, slightly degradable by-products are produced; this production is the most serious issue associated with such treatment. We observed the acceleration of by-products degradation with decrease in an oxygen concentration in a treatment atmosphere.
- Yamamoto, Shin,Amemiya, Takashi,Murabayashi, Masayuki,Itoh, Kiminori
-
p. 1046 - 1047
(2007/10/03)
-
- Hazardous air pollutants formation from reactions of raw meal organics in cement kilns
-
Thermally induced chlorination, condensation, and formation reactions of raw meal organic surrogates were investigated on different types of surfaces. The System for Thermal Diagnostic Studies provided a powerful tool to study these reactions under defined reaction conditions, which were related to typical conditions in the preheater zone of cement kiln. Experiments were conducted with benzene and benzene/myristic acid (C6H6/C13H27COOH) mixtures in a quartz reactor containing different chlorinating catalysts/reagents over a temperature range of 300-500°C. Reaction products were trapped in-line and analyzed by GC-MS. A mixture of chlorides of calcium, potassium, aluminium and iron was highly effective for chlorination/condensation reactions of benzene and benzene/myristic acid mix at temperatures above 300°C. The same behavior was observed only when calcium chloride and potassium chloride were used as chlorinating catalyst/reagent. This result showed that transition metal chlorides like FeCl3 are not necessary for chlorination/condensation of organics under post-combustion conditions. Methylene chloride was the major chlorinated product followed by chloroform and various other C1, C2 and C6 chlorinated products. Yields of chlorinated aliphatics were highest at 400°C for both benzene and benzene/myristic acid mix. C6 products were mainly mono- to hexa-chlorinated benzenes with trace amounts of chlorinated phenols. The major chlorinated products observed in this study (i.e., methylene chloride, chloroform, chloroethanes and monochlorobenzene) were also present as major chlorinated hydrocarbons in the cement kiln field emission data.
- Sidhu, Sukh,Kasti, Nabil,Edwards, Phil,Dellinger, Barry
-
p. 499 - 506
(2007/10/03)
-
- Transient puffs of trace organic emissions from a batch-fed waste propellant incinerator
-
Emissions data have been obtained from a waste propellant incinerator. The incinerator is a dual fixed hearth, controlled air incinerator equipped with acid gas and particulate scrubbing. Puffing has been evident in this waste propellant incinerator by spikes in the CO concentration. Transient puffs of organics may travel down the combustion chambers and lead to stack emissions. The major conclusions from this study are that (1) transient puffs are formed due to the semi-batch feed nature of the combustion process (causing a local oxygen deficiency) and high water content of the desensitized propellant; (2) in batch-fed combustors, puffs can contribute to most of the organic emissions (which are relatively low) measured with US EPA sampling and analytical methods; (3) it is estimated that batch-fed combustion contributes up to 7-18 times more emissions than steady-state combustion will generate; (4) by applying dispersion analyses to determine the amount of oxygen deficiency in the flame zone, the combustion zone concentration of CO during batch-fed operation could be as high as 160,000 ppm, compared to a measured peak stack concentration of 1200 ppm CO; and (5) an organic sample is collected and averaged over at least a 2-h period that smooths out the transient peaks of organics emissions during batch-fed operation. For emissions that are associated with long-term potential health impacts, this is an appropriate sampling method. However, if a compound has a short-term potential health impact, it may be important to measure the time-resolved emissions of the compound.
- Hart, John R.
-
p. 559 - 569
(2007/10/03)
-
- Dicarbonyl-containing compounds
-
This invention relates to chemical compounds that contain adjacent carbonyl groups, which effectively inhibit the biological, chemical, and/or physical properties of enzymes and other medicinally-significant proteins. In particular, the invention relates to dicarbonyl compounds that are capable of acting as enzyme inhibitors, including irreversible inhibitors of HIV-1 protease.
- -
-
-
- Chemistry of the biosynthesis of halogenated methanes: C1-organohalogens as pre-industrial chemical stressors in the environment?
-
We have chemical evidence that in the biosynthesis of the halomethanes C1H(4-n),X(n) (n = 1-4) three different pathways of biogenic formation have to be distinguished. The formation of methyl chloride, methyl bromide, and methyl iodide, respectively, has to be considered as a methylation of the respective halide ions. The dihalo- and trihalomethanes are formed via the haloform and/or via the sulfo-haloform reaction. The possible formation of tetrahalomethanes may involve a radical mechanism. Methionine methyl sulfonium chloride used as substrate in the incubation together with chloroperoxidase (CPO) and H2O2 gave high yields of monohalomethanes only. We were able to show that next to the CPO/H2O2 driven haloform reaction of carbonyl activated methyl groups also methyl-sulphur compounds - e.g. dimethylsulfoxide, dimethylsulfone, and the sulphur amino acid methionine - can act as precursors for the biosynthesis of di- and trihalogenated methanes. Moreover, there is some but not yet very conclusive evidence for an enzymatic production of tetrahalogenated methanes. In our experiments with chloroperoxidase involving amino acids and complex natural peptide based substrates, dihalogenated acetonitriles and several other volatile halogenated but yet unidentified compounds were formed. On the basis of these experiments we like to suggest that biosynthesis of halogenated nitriles occurs in general and therefore a natural atmospheric background should exist for halogenated acetonitriles and halogenated acetaldehydes, respectively.
- Urhahn, Thorsten,Ballschmiter, Karlheinz
-
p. 1017 - 1032
(2007/10/03)
-
- Formation of complex organochlorine species in water due to cavitation
-
Sonication at 900 kHz was carried out on aqueous solutions of chloroform in the concentration range 25 to 500 mg/L. The formation of chlorinated hydrocarbons was detected by means of GC/MS analyses. For instance, carbon tetrachloride, chlorinated ethanes, and chlorinated ethenes were formed after 10 min of sonication. The greatest concentration of any product was 6 mg/L. Sonication of aqueous chloroform with phenol present produced chlorophenols, and with benzene present produced phenol, chlorobenzene and chlorophenols. These results are significant for the evaluation of sonication as a method of eliminating chlorinated organic compounds from water. They also have significance in supporting the notion that some complex organochlorines may be formed naturally in the environment. Some chloroform and methyl chloride are produced in nature and could react with other organic compounds to form more complex organochlorines through natural processes which have an action similar to cavitation, e.g. waterfalls and breaking waves.
- Kruus, Peeter,Beutel, Lise,Aranda, Rocio,Penchuk, Jaan,Otson, Rein
-
p. 1811 - 1824
(2007/10/03)
-
- Catalytic activity of spinel-type catalysts in oxidative chlorination of methane
-
The effect of adding cobalt chromite to copper-chromium spinel catalysts on their activity in oxidative chlorination of methane was studied.
- Vlasenko,Chernobrivets
-
p. 431 - 434
(2007/10/03)
-
- The pyrolysis of CCl4 and C2Cl6 in the gas phase. Mechanistic modeling by thermodynamic and kinetic parameter estimation
-
A detailed radical reaction mechanism is proposed to describe the thermal reactions of CCl4 and C2Cl6 in the gas phase quantitatively. A consistent set of activation energies and preexponential factors for all elementary reactions, in combination with enthalpies of formation and entropies for all species involved, is computer optimized to fit experimental pressure-rise curves and concentration profiles. For this purpose new experimental results on the pyrolysis of CCl4 are used, together with published kinetic data on the pyrolysis of C2Cl6 (in the absence and in the presence of Cl2).
- Huybrechts,Narmon,Van Mele
-
-
- Experimental study on the thermal oxidation of 1,3-hexachlorobutadiene at 500-1100°C
-
Thermal degradation processes of 1,3-hexachlorobutadiene (C4Cl6) have been studied using a tubular flow reactor at 1 atm over the temperature range 500-1100°C for residence times of 2 seconds. Kinetic studies were performed with mixtures of 1000 ppmV of C4Cl6 in air. Overall Arrhenius parameters for the destruction of C4Cl6 were determined between 700 and 850°C. About 30 molecular halogenated products from C1 to C8 formed by pyrolysis or oxidation of 1,3-hexachlorobutadiene over the investigated temperature range were identified. Concentration profiles of major products (CO2, Cl2, CO, COCl2, C2Cl4, CCl4) and some minor products (C3Cl4O, C4Cl4O, C6Cl6, C3Cl4 and C3Cl6) have been measured as a function of temperature. Phosgene is the major chlorinated intermediate product. Detection of some aromatics such as hexachlorobenzene and octachlorostyrene show the importance of the molecular growth pathways in the chemical mechanism. Reaction pathways of main products are proposed and corresponding reaction enthalpies are estimated.
- Baillet,Fadli,Sawerysyn
-
p. 1261 - 1273
(2007/10/03)
-
- Reactions of trifluoromethylthiocopper with halomethanes
-
The reaction of trifluoromethylthiocopper with halomethanes, namely di-and triiodo-, dibromodichloro-, dibromochlorofluoro-, dibromo-difluoro-, bromochlorofluoro-, phenyltrichloro-, bromocyano-and dibromofluoro-methanes, has been investigated in detail. In addition to the expected compounds, the formation of unusual products such as bis (trifluoromethyl) trithiocarbonate, dimethyl (trifluoromethylthio) benzene, bis (trifluoromethylthio) fluoromethane, (trifluoromethylthio) carbonyl fluoride, carbon disulfide, carbon tetrachloride, trifluoromethylthio-benzoate, etc. was observed. In some cases, bis (trifluoromethylthio) mercury has been used instead of trifluoromethylthiocopper. The mechanism of formation of the various products and their mass spectral fragmentation behavior are described.
- Munavalli,Rossman,Rohrbaugh,Ferguson,Durst
-
-
- COPPER-CONTAINING CATALYSTS FOR OXIDATIVE CHLORINATION OF METHANE
-
Comparative studies are made of catalytic activity and stability of "salt" (based on CuCl2) and copper chromium spinel catalysts for oxidative chlorination of methane.
- Vlasenko, V. M.,Chernobrivets, V. L.
-
p. 1419 - 1422
(2007/10/03)
-
- Leukotriene B4 synthesis inhibitors
-
This invention relates to a compound of the formula: STR1 or a pharmaceutically acceptable salt thereof wherein X is oxygen, sulfur, --CH=CH--, or --CH=N--; wherein R1 is --CO2 R2 or tetrazole; wherein R2 is hydrogen, alkyl of 1 to 6 carbons or a pharmaceutically acceptable cation; wherein R is an alkyl of from 1 to 20 carbons, --(CH2)p CF3 or --(CH2)q R3 wherein R3 is alkoxy, phenoxy or alkoxy substituted phenoxy wherein the alkoxy group has from 1 to 8 carbons; wherein p and q are integers from 0 to 20; wherein n is 0 or 1; and wherein m is 0, 1, 2, or 3.
- -
-
-
- Fluoride anion catalyzed halogen dance in polyhalomethanes
-
Tetrabutylammonium fluoride catalyzes the exchange of halogens between tetrahalomethanes.The presence of small amounts of haloform is suspected to be a necessary co-catalyst.Key Words: tetrabutyl ammonium fluoride; tetrahalomethanes; halogen exchange in.
- Sasson, Y.,Kitson, F.,Webster, O, W.
-
p. 599 - 600
(2007/10/02)
-
- Iodine Atoms and Iodomethane Radical Cations: Their Formation in the Pulse Radiolysis of Iodomethane in Organic Solvents, Their Complexes, and Their Reactivity with Organic Reductants
-
Pulse radiolysis of iodomethane in various organic solvents leads to formation of iodine atoms or iodomethane radical cations, which in turn form complexes with iodomethane or with the solvent.Radiolysis in cyclohexane gives CH3I*I, which exhibits an absorption peak at 390 nm, whereas radiolysis in benzene forms the solvent complex, C6H6*I, which exhibits an intense broad absorption centered at 490 nm.Radiolysis of iodomethane in acetone, benzonitrile, and halogenated hydrocarbons results in formation of the radical cation CH3I.+.In the former two solvents, this species forms a complex with another molecule of iodomethane to give (CH3))2+, which absorbs at 420 nm, in agreement with previous results in aqueous solutions, but in halogenated hydrocarbons it forms complexes with the solvents, absorbing at 320-360 nm, i.e. near the absorption of monomeric CH3I.+ in water.Complexes of I atoms oxidize phenol and triphenylamine relatively slowly whereas complexes of CH3I.+ react more rapidly.The reactivity of the CH3I.+*RX complexes increases in the order of RX = CH2Cl2, CHCl3, CH2Br2, CCl4, CH3I, and for each complex the reactivity with phenol increases with increase in electron donating power of substituents.Replacing the methyl group of iodomethane radical cation with ethyl or isopropyl decreases the reactivity, whereas trifluoromethyl increases the reactivity.These oxidation reactions proceed via an intermediate complex between the iodine species and the organic reductant.
- Shoute, Lian C. T.,Neta, P.
-
p. 4411 - 4414
(2007/10/02)
-
- NEW SYNTHESIS OF POLYCHLORO(TRIFLUOROMETHYL)BENZENES AND HIGHLY STRAINED POLYCHLORO(TRICHLOROMETHYL)BENZENES
-
Several polychloro(trifluoromethyl)benzenes have been prepared by treatment of the corresponding polychlorobenzenes with CCl3F and AlCl3.The resulting trifluoromethyl derivatives, by reaction with the same inorganic halide in CS2, give their trichloromethyl analogues.
- Riera, Juan,Castaner, Juan,Carilla, Jose,Robert, Ana
-
p. 3825 - 3828
(2007/10/02)
-
- THE SYNTHESIS OF PERFLUORO(N,N-DIALKYLCARBAMOYL FLUORIDES) BY THE REACTION OF PERFLUORO(N,N-DIALKYLMETHYLAMINES) WITH OLEUM
-
A convenient one-step preparation of new perfluoro(N,N-dialkylcarbamoyl fluorides) f=R'f=C2F5 (1b); Rf=C2F5, R'f=n-C3F7 (2b); Rf=R'f=n-C3F7 (3b); Rf=n-C3F7, R'f=n-C4F9 (4b); Rf=n-C3F7, R'f=n-C5F11 (5b); Rf=R'f=n-C4F9 (6b); Rf=n-C3F7, R'f=CF3 (7b); Rf=n-C4F9, R'f=CF3 (8b); Rf=n-C5F11, R'f=CF3 (9b)> is described: the corresponding perfluoro(N,N-dialkylmethylamines) are treated with oleum.Catalysts (HgSO4 and MoCl5) improved the yields and the purity of the products obtained.Conditions for the preparation of nine new perfluorocarbamoyl fluorides and their properties are described: several reactions using 1b and 9b were conducted.
- Abe, Takashi,Hayashi, Eiji
-
p. 293 - 312
(2007/10/02)
-
- MULTIPHOTON IONIZATION OF CHLOROMETHANES WITH 193-NM EXCIMER LASER RADIATION IN ARGON MATRICES
-
The 193-nm output of an excimer laser has been coupled with the matrix isolation technique to demonstrate the feasibility of multiphoton ionization of matrix-isolated species.CCl4, CHCl3, and CH2Cl2 were, in turn, deposited in argon and (in some cases) nitrogen matrices and irradiated for between 5 min and 3 h.For CCl4 and CH2Cl2, the major product was the parent cation or species derived directly thereform, while more varied species, including the CHCL3(-) anion, were observed in the CHCl3 studies.In addition, neutral fragments were observed in a manner similar to previous resonance radiation and proton-beam radiolysis studies.Irradiation of the sample mixture during the deposition process led to increased product yield, as well as additional products for some of the systems.The laser irradiation time, power, and repetition rate were varied over a wide range, and a relative insensitivity to these parameters was noted.
- Machara, Nicholas P.,Ault, Bruce S.
-
p. 1908 - 1913
(2007/10/02)
-
- Method for preparing 3-ethylbenzophenone
-
The present invention provides a method for preparing 3-ethylbenzophenone in a high purity which comprises the steps of alkylating benzene with ethylene with the aid of an alkylating catalyst to obtain an alkylated product composed mainly of unreacted benzene, ethylbenzene, polyethylbenzenes and heavier by-products; subjecting the alkylated product to distillation in order to recover therefrom a fraction which has a temperature range of boiling points within the range of 275° to 310° C. (in terms of atmospheric pressure); dehydrogenating the recovered fraction at a reaction temperature within the range of 200° to 700° C. in the presence of a dehydrogenating catalyst; oxidizing the dehydrogenated fraction in a liquid phase; and performing distillation to recover therefrom 3-ethylbenzophenone represented by the formula: STR1
- -
-
-
- Preparation and characterization of chlorodifluorosulfur(IV) hexafluoroarsenate
-
The stable salt [SF2Cl]+[AsF6]- was prepared and isolated in good yield from the reaction of trans-CF3SF4Cl and AsF5. The identity and ionic nature of this salt were established by its elemental analysis and by 19F NMR, IR, and mass spectral studies. Redistribution of the halogen atoms in the cation of [SF2Cl]+[AsF6]- to form [SF3]+[AsF6]- and [SCl3]+[AsF6]- in liquid SO2 occurred at ambient temperature. In the presence of NaF or NaCl, [SF2Cl]+ was converted to [SF3Cl] or [SF2Cl2], respectively, at low temperature, where redistribution occurred to form SF4 and [SCl4].
- Alam, Kohrshed,Shreeve, Jean'ne M.
-
p. 1374 - 1375
(2008/10/08)
-
