Conversion of chloroform to hydrochloric acid by reaction with hydrogen and water vapor

Chuang, Shien C.; Bozzelli, Joseph W.

doi:10.1021/es00148a004

Cited by 38 publications

(16 citation statements)

References 15 publications

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“…It is apparent that wall effects become very important at temperatures above about 1200 K for 4 mm id reactors. These results are in agreement with the trends observed in previous studies at this laboratory (Chuang and Bozzelli (1986) and Chang and Bozzelli (1987». It should be noted that both accelerating and inhibiting wall effects have been observed in the various systems we have studied.…”

Section: Resultssupporting

confidence: 94%

Reactions of Chlorinated Benzenes in H2 and in H₂/O₂Mixtures: Thermodynamic Implications on Pathways to Dioxin

Ritter

Bozzelli

1990

Combustion Science and Technology

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Thermal Reactions of Chi oro and Dichlorobenzene in H, and Chlorobenzene in H,jO, mixtures were studied using tubular flow reactors between 835 to 1275 K, I atm pressure. Complete conversion of ehlorobenzenes in hydrogen required temperatures above I lOOK. while in mixtures containing small quantities of O 2 equivalent conversion occurred at 893 K. Major products in both systems were benzene, carbon solids and Hel, with CH 4 and C 2 H 6 also present in low concentrations.Results from detailed kinetic mechanisms showed that displacement of the chlorine by atomic hydrogen (H addition to the ring with subsequent beta scission of the chlorine from the activated chlorocyclohexadienyl radical) was responsible for conversion of the chlorobenzene. O 2 can initiate the chain mechanism by H 2 + O 2 .-H0 2 + H, which explains the lower required temperature for conversion when Oxygen is present.The molecule and radical thermodynamic properties required for the kinetic models led to development of thermodynamic parameters for chlorinated aromatics including dioxins and dibenzofurans. These properties demonstrate that it is thermodynamically more favorable to form chlorinated dioxins and dibenzofurans over the analogous non-chlorinated species. The pathways presented demonstrate plausible elementary reactions to chlorinated dibenzofuran and dioxin formation in incineration and combustion processes.We suggest two regimes in incineration or high temperature reaction systems, where homogeneous dioxin formation may occur. The first is a fuel rich (pyrolysis) region where molecular weight growth may occur. The second is a region where poly-phenyls and aromatics may be present with oxygen and oxy radicals at temperatures which favor addition reactions over oxidation of the ring systems.

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Section: Resultssupporting

confidence: 94%

Reactions of Chlorinated Benzenes in H2 and in H₂/O₂Mixtures: Thermodynamic Implications on Pathways to Dioxin

Ritter

Bozzelli

1990

Combustion Science and Technology

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“…Mono-and dihalocarbenes were particularly well studied regarding the determination of kinetic rate constants. The determination of the steps that follow CHCl 3 pyrolysis has been the subject of numerous investigations [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Flow and shock tube techniques have been employed using diverse detection methods to resolve the kinetics [2][3][4][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Determination of the Rate Constant of the Reaction of CCl₂ with HCl

Gómez

D'Accurso

Manzano

et al. 2014

Int J of Chemical Kinetics

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The rate constant of the reaction between CCl2 radicals and HCl was experimentally determined. The CCl2 radicals were obtained by infrared multiphoton dissociation of CDCl3. The time dependence of the CCl2 radicals' concentration in the presence of HCl was determined by laser‐induced fluorescence. The experimental conditions allowed us to associate the decrease in the concentration of radicals to the self‐recombination reaction to form C2Cl4 and to the reaction with HCl to form CHCl3. The rate constant for the self‐recombination reaction was determined to be in the high‐pressure regime. The value obtained at 300 K was (5.7 ± 0.1) × 10−13 cm3 molecule−1 s−1, whereas the value of the rate constant measured for the reaction with HCl was (2.7 ± 0.1) × 10−14 cm3 molecule−1 s−1.

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“…Chloroethylenes are dechlorinated by H addition displacement reactions which are important channels for reducing the chlorine content of unsaturated chlorocarbons [7,11]. The H atom can add to C 2 HCl 3 to form C 2 H 2 Cl 3 radical as shown in reaction (6). The [C 2 H 2 Cl 3 ] # complex is initially "hot" since, in addition to the thermal energy, it contains energy resulting from the formation of the stronger C-H bond relative to π bond broken [7,14].…”

Section: Major Reaction Pathways For Products In C 2 Hcl 3 /H 2 Reactmentioning

confidence: 99%

“…This suggests that the emission of toxic chlorine containing organic products may persist through an oxygen-rich incineration, as it is one of the more stable sinks for the chlorine. It is important to understand both their pyrolysis and oxidation [6,7].…”

Section: Introductionmentioning

confidence: 99%

Thermal decomposition of trichloroethylene under a reducing atmosphere of hydrogen

Won

2009

Korean J. Chem. Eng.

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The thermal reaction of trichloroethylene (TCE: C 2 HCl 3 ) has been conducted in an isothermal tubular flow reactor at 1 atm total pressure in order to investigate characteristics of chlorinated hydrocarbons decomposition and pyrolytic reaction pathways for formation of product under excess hydrogen reaction environment. The reactions were studied over the temperature range 650 to 900 o C with reaction times of 0.3-2.0 s. A constant feed molar ratio C 2 HCl 3 : H 2 of 4 : 96 was maintained through the whole experiments. Complete decay (99%) of the parent reagent, C 2 HCl 3 was observed at temperature near 800 o C with 1 s reaction time. The maximum concentration (28%) of C 2 H 2 Cl 2 as the primary intermediate product was found at temperature 700 o C where up to 68% decay of C 2 HCl 3 occurred. The C 2 H 3 Cl as highest concentration (19%) of secondary products was detected at 750 o C. The one less chlorinated methane than parent increased with temperature rise subsequently. The number of qualitative and qualitative chlorinated products decreased with increasing temperature. HCl and dechlorinated hydrocarbons such as C 2 H 4 , C 2 H 6 , CH 4 and C 2 H 2 were the final products at above 800 o C. The almost 95% carbon material balance was given over a wide range of temperatures, and trace amounts of C 6 H 6 , C 4 H 6 and C 2 HCl were observed above 800 o C. The decay of reactant, C 2 HCl 3 and the hydrodechlorination of intermediate products, resulted from H atom cyclic chain reaction via abstraction and addition replacement reactions. The important pyrolytic reaction pathways to describe the important features of reagent decay, intermediate product distributions and carbon mass balances, based upon thermochemical and kinetic principles, were suggested. The main reaction pathways for formation of major products along with preliminary activation energies and rate constants were given.

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Conversion of chloroform to hydrochloric acid by reaction with hydrogen and water vapor

Cited by 38 publications

References 15 publications

Reactions of Chlorinated Benzenes in H2 and in H₂/O₂Mixtures: Thermodynamic Implications on Pathways to Dioxin

Reactions of Chlorinated Benzenes in H2 and in H₂/O₂Mixtures: Thermodynamic Implications on Pathways to Dioxin

Determination of the Rate Constant of the Reaction of CCl₂ with HCl

Thermal decomposition of trichloroethylene under a reducing atmosphere of hydrogen

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Conversion of chloroform to hydrochloric acid by reaction with hydrogen and water vapor

Cited by 38 publications

References 15 publications

Reactions of Chlorinated Benzenes in H2 and in H2/O2Mixtures: Thermodynamic Implications on Pathways to Dioxin

Reactions of Chlorinated Benzenes in H2 and in H2/O2Mixtures: Thermodynamic Implications on Pathways to Dioxin

Determination of the Rate Constant of the Reaction of CCl2 with HCl

Thermal decomposition of trichloroethylene under a reducing atmosphere of hydrogen

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Reactions of Chlorinated Benzenes in H2 and in H₂/O₂Mixtures: Thermodynamic Implications on Pathways to Dioxin

Reactions of Chlorinated Benzenes in H2 and in H₂/O₂Mixtures: Thermodynamic Implications on Pathways to Dioxin

Determination of the Rate Constant of the Reaction of CCl₂ with HCl