75-62-7Relevant articles and documents
Kinetics of the Reaction of CCl3 + Br2 and Thermochemistry of CCl3 Radical and Cation
Hudgens, Jeffrey W.,Johnson, Russell D.,Timonen, R. S.,Seetula, J. A.,Gutman, D.
, p. 4400 - 4405 (1991)
The rate constant of the CCl3 + Br2 -> CCl3Br + Br reaction was determined as a function of temperature between 300 and 532 K and fit to an Arrhenius expression: k1 (L mol-1 s-1) = (1.8 +/- 0.4) x 108 exp-1/RT>.The reaction was studied in a tubular flow reactor by using laser photolysis to produce the CCl3 reactant and photoionization mass spectrometry to monitor CCl3 in time-resolved experiments.Previously published kinetic data were reevaluated to obtain k-1, the rate constant for the reverse reaction, and recent spectroscopic data were used to calculate accurate entropies and heat capacities.The values of k-1, k1, and these calculated thermodynamic properties were used in a third law determination to obtain ΔH0f,298.15(CCl3) = 17.0 +/- 0.6 kcal mol-1 and ΔH0f,0(CCl3) = 16.7 +/- 0.6 kcal mol-1.This information was combined with spectroscopic data on CCl3+ to obtain ΔH0f,298.15(CCl3+) = 205.2 +/- 0.6 kcal mol-1 and ΔH0f,0(CCl3+) = 203.7 +/- 0.6 kcal mol-1.Bond energies of several relevant compounds and tables of thermodynamic functions for CCl3 and CCl3+ are presented.An improved heat of formation for the CCl3O2 radical, ΔH0f,298.15(CCl3O2) = 2.7 +/- 1.1 kcal mol-1, is also reported.
Translational Energy Dependence of Gas-Phase Reactions of Halides with Halogenated Alkanes
Hop, C. E. C. A.,McMahon, T. B.
, p. 10582 - 10586 (1991)
The gas-phase bimolecular nucleophilic substitution reactions Br- + CCl4 -> BrCCl3 + Cl-, Br- + CF2Cl2 -> BrCF2Cl + Cl-, and Cl- + CBr4 -> ClCBr3 + Br- were studied as a function of the center-of-mass energy with Fourier transform ion cyclotron resonance spectrometry.From the energy dependence and the threshold energies of these reactions, conclusions were drawn concerning the mechanism involved.
MANUFACTURING METHOD OF TETRAHALOMETHANE
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Paragraph 0036; 0037; 0039-0054, (2018/05/15)
PROBLEM TO BE SOLVED: To provide a method capable of manufacturing tetrahalomethane at high efficiency. SOLUTION: There is provided a method for manufacturing tetrahalomethane by bromination of trihalomethane selected from trichloromethane or tribromomethane, including mixing the trihalomethane, bromine, sodium hypochlorite, sodium hydroxide, and water to brominate the trihalomethane. It is preferable to mix trihalomethane of 0.1 to 10 mol, sodium hypochlorite of 0.1 to 10 mol, sodium hydroxide of 0.1 to 20 mol, and water of 1 to 50 mol, with respect to bromine of 1 mol. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
Chemistry of the biosynthesis of halogenated methanes: C1-organohalogens as pre-industrial chemical stressors in the environment?
Urhahn, Thorsten,Ballschmiter, Karlheinz
, p. 1017 - 1032 (2007/10/03)
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.