79-28-7Relevant academic research and scientific papers
Compounds and methods for the reduction of halogenated hydrocarbons
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Page/Page column 21-22, (2017/12/27)
The present application relates to methods for the reduction of halogenated hydrocarbons using compounds of Formula (I): wherein the reduction of the halogenated compounds is carried out, for example, under ambient conditions without the need for a transition metal containing co-factor. The present application also relates to methods of recovering precious metals using compounds of Formula (I) that are absorbed onto a support material.
Liquid-phase oxidation of bromovinyl compounds with molecular oxygen
Bayatyan,Bayatyan,Saakyan
, p. 1849 - 1852 (2008/02/08)
Liquid-phase oxidation of bromovinyl compounds with the aim to obtain the corresponding α-bromo acids was studied.
gem-Dihalocyclopropane formation by iron/copper activation of tetrahalomethanes in the presence of nucleophilic olefins. Evidence for a carbene pathway
Léonel, Eric,Lejaye, Michael,Oudeyer, Sylvain,Paugam, Jean Paul,Nédélec, Jean-Yves
, p. 2635 - 2638 (2007/10/03)
The activation of CBr4 and CCl4 by a bimetallic iron/copper couple in acetonitrile is a new, inexpensive, nontoxic and efficient procedure for gem-dibromo- and gem-dichloromethylenation of nucleophilic alkenes. This new route to gem-dihalocyclopropanes involves dihalocarbene species.
Novel photocatalytic mechanisms for CHCl3, CHBr3, and CCl3CO2 degradation and the fate of photogenerated trihalomethyl radicals on TiO2
Choi, Wonyong,Hoffmann, Michael R.
, p. 89 - 95 (2007/10/03)
The photocatalytic degradation of CHCl3, CHBr3, CCl4, and CCl3CO2- is investigated in aqueous TiO2 suspensions. A common intermediate, the trihalomethyl radical, is involved in the degradation of each substrate except for CCl3CO2-, CHCl3 and CHBr3 are degraded into carbon monoxide and halide ions in the absence of dissolved oxygen. The anoxic degradation proceeds through a dihalocarbene intermediate, which is produced by sequential reactions of the haloform molecule with a valence band hole and a conduction band electron. Carbon dioxide and halide ion are formed as the primary products during CHCl3 degradation in the presence of oxygen. Under these conditions, the trihalomethyl radicals react rapidly with dioxygen. At pH > 11, degradation of the haloforms is enhanced dramatically. This enhancement is ascribed to photoenhanced hydrolysis. The secondary reactions of the trichloromethyl radical generated during CCl4 photolysis is strongly influenced by the nature of the electron donors. Both ·CCl3 and Cl- production increase substantially when 2-propanol is present as an electron donor. A new photocatalytic mechanism for CCl3CO2- degradation, which involves the formation of a dichlorocarbene intermediate, is proposed.
FORMATION OF HETEROCYCLIC HAZARDOUS COMPOUNDS BY THERMAL DEGRADATION OF ORGANIC COMPOUNDS
Bieniek, Dieter,Bahadir, Muefit,Korte, Friedhelm
, p. 719 - 722 (2007/10/02)
2,3,7,8-Tetrabromodibenzofuran in ppm concentrations can be generated via reductive debromination and subsequent intramolecular cyclization during thermolysis of polybrominated aromatic compounds such as decabromodiphenyl ethers which are used as flame retardants in plastics.The respective tetrabromobenzodioxin isomer is produced in moderate amounts.In analogy to the chlorinated isomers the formation of toxic substances from incineration or fire accident constitutes a potential hazard.
Syntheses and Reactions of Trifluoromethylchalcogen Derivatives of Alkynes
Haas, Alois,Kraechter, Hans-Udo
, p. 1833 - 1840 (2007/10/02)
(Trifluoromethylchalcogenyl)alkynes 1 are obtained by treating the corresponding bromoalkynes with CuECF3 (E = S, Se).Only bis(trifluoromethylthio)ethyne (1a) is not obtained directly but is synthesized from BrCH=CHBr via CF3SCH=CHSCF3 and CF3S(Br)CH-CH(Br)SCF3 followed by subsequent HBr elimination.Photolysis and decomposition of 1a in the presence of (C6H5)3P generate the thiophene derivatives 3a, b.During pyrolysis the 1,4-dithiine 3c is formed as well.Addition of Br2 produces the cis/trans isomers 2a, b.Cycloaddition to dicyclopentadiene, hexachlorocyclopentadiene, anthracene, tetrachloro-5,5-dimethoxycyclopentadiene, tetraphenylcyclopentadienone, and dibromocarbene yield the homocycles 4a-e and 5a. 1,3-Dipolar additions of 1a to diphenylnitrilimine, PhN3, and R2CN2 (R = H, CH3, C2H5) lead to the heterocycles 6a, c and 7b-e.Pyrazole 7e decomposes to 7f and 5b.The furan derivatives 9a, b are obtained from 1,3-oxathiolones 8a, b and 1a. 1a reacts with S4N4 or SO3 to give the seven-membered rings 10 and 11.
Effects of Solvent and Additives on the Rearrangement Pathway of the Seyferth Reaction
Lambert, Joseph B.,Boch, Richard J.,Larson, Eric G.
, p. 3054 - 3059 (2007/10/02)
The Seyferth reagent has dual reactivity with electron-deficient alkenes. trans-1,2-Dichloroethene reacts both with the free carbene to give cyclopropane stereospecifically and with a complex between carbene and a second molecule of Seyferth reagent (homogeneous catalysis) to give a rearranged propene.The addition of other materials to the reaction mixture can have a profound effect on the ratio of the two pathways.Good ? donors such as p-xylene decrease the pathway to rearranged propene via the complexed carbene.Such materials thus serve as inhibitors to the process of homogeneous catalysis by forming a competing complex that does not go on to propene but instead reverts to free carbene.The existence of the inhibitor-carbene complex is supported by concentration studies.The presence of insoluble materials such as zinc chloride, on the other hand , serves to decrease the pathway that leads through free carbene to the cyclopropane.Free carbene may react with the surface of the additive and be removed as a reactive species.This latter process would have no effect on carbene previously complexed with the homogeneous catalyst, the Seyferth reagent , which could still proceed to rearranged propene.
REARRANGEMENT AND CATALYSIS IN THE SEYFERTH REACTION.
Lambert,Bosch,Mueller,Kobayashi
, p. 3584 - 3589 (2007/10/02)
The Seyferth reagent PhHgCBr//3 reacts with trans-1,2-dichloroethene to give two major products, trans-1,1-dibromo-2,3-dichlorocyclopropane (C) and 1,1-dibromo-3,3-dichloropropene (P). The stereospecifically formed cyclopropane is consonant with a singlet carbene mechanism, but the rearranged propene requires a second intermediate. Observation that the concentration ratio left bracket P right bracket / left bracket C right bracket is inversely proportional to the concentration of the alkene demonstrates that there are two intermediates, that the cyclopropane comes from the first-formed intermediate, and that the propene comes from the second-formed intermediate.
