108-70-3Relevant academic research and scientific papers
Effects of FeS on the transformation kinetics of γ-hexachlorocyclohexane
Liu, Xiangmei,Peng, Ping'an,Fu, Jiamo,Huang, Weilin
, p. 1822 - 1828 (2003)
Distinctly different rates and pathways were observed for abiotic transformation of γ-hexachlorocyclohexane (γHCH) between homogeneous systems and systems containing FeS solid. The observed half-lives of γ-HCH decrease from about 1136 and 126 d in homogen
Photochemistry of Polyhaloarenes. 8. The Photodechlorination of Pentachlorobenzene
Freeman, Peter K.,Ramnath, N.,Richardson, Alan D.
, p. 3643 - 3646 (1991)
Measurements of the intersystem crossing yield of pentachlorobenzene triplet, the quenching of photodechlorination of pentachlorobenzene with fumaronitrile, the dependence of the fluorescence lifetime, and the quantum yield of photodechlorination of pentachlorobenzene upon substrate concentration and the dependence of relative product concentration upon light intensity provide evidence for three pathways to product: direct fission of singlet and triplet and fragmentation of triplet excimer.
Chlorination of aniline and methyl carbanilate by N-chlorosuccinimide and synthesis of 1,3,5-trichlorobenzene
Davis, Matthew C.
, p. 1100 - 1108 (2009)
Aniline undergoes regioselective trichlorination by N-chlorosuccinimide (NCS) in acetonitrile in good yield. The product 2,4,6-trichoroaniline was converted into 1,3,5-trichlorobenzene by reduction of its diazonium salt. Reaction of the methyl carbamate of aniline with NCS gave only the 2,4-dichlorophenyl carbamate. Copyright Taylor & Francis Group, LLC.
Participation of Oligochlorobenzenes in the Base-Catalyzed Halogen Dance
Mach, Martin H.,Bunnett, Joseph F.
, p. 4660 - 4666 (1980)
The three trichlorobenzenes fail to participate in the base-catalyzed halogen dance even on treatment with the favorable base/solvent combination potassium tert-butoxide in hexamethylphosphoric triamide.However, 1,2,3,5- and 1,2,4,5-tetrachlorobenzenes undergo disproportionation to penta- and trichlorobenzenes as well as interconversion into each other.Pentachlorobenzene disproportionates to hexa- and tetrachlorobenzenes, but further reactions of C6Cl6 form pentachlorophenol.Substitution reactions to form aryl tert-butyl ethers are observed as side reactions and are believed to occur by the SNAr mechanism.The phenols produced in several reactions apparently result from E2 cleavage of these ethers.These observations are possibly relevant to the mechanism of formation of 2,3,7,8-tetrachlorodibenzo-p-dioxin from 1,2,4,5-tetrachlorobenzene.
Electroreductive dechlorination of α-hexachlorocyclohexane catalyzed by iron porphyrins in nonaqueous media
Zhu, Weihua,Ni, Cui,Liang, Lili,Li, Junwen,Li, Minzhi,Ou, Zhongping,Kadish, Karl M.
, p. 519 - 527 (2014)
Two iron porphyrins, (TPP)FeCl and (OEP)FeCl, where TPP and OEP are the dianions of tetraphenylporphyrin and octaethylporphyrin, respectively, were utilized as catalysts for the electroreductive dechlorination of α-hexachlorocyclohexane (α-HCH) which was monitored by electrochemistry, in situ UV-visible spectroelectrochemistry and controlled potential electrolysis in N,N′-dimethylformamide. GC-MS analysis of the α-HCH degradation products revealed the stepwise formation of pentachlorocyclohexene and tetrachlorocyclohexadiene as intermediates, prior to generation of the final dechlorination products which consisted of an isomeric mixture of trichlorobenzenes. Based on identification of the intermediates and final products in the reaction, an overall dechlorination mechanism of α-hexachlorocyclohexane is proposed.
Dechlorination of chlorinated benzenes by an anaerobic microbial consortium that selectively mediates the thermodynamic most favorable reactions
Beurskens,Dekker,Van Den Heuvel,Swart,De Wolf,Dolfing
, p. 701 - 706 (1994)
A chlorinated benzene dechlorinating anaerobic microbial consortium was obtained by selective enrichment with hexachlorobenzene (HCB) and lactate from a freshwater sediment sample that originated from an area with proven in situ HCB dechlorination. The consortium was used to determine compound selectivity and relative dechlorination rates by incubation with the individual chlorinated benzenes under methanogenic conditions. The selectivity of the enrichment culture showed an interesting correlation with the thermodynamics of the various dechlorination steps: from the 19 dechlorination reactions possible with benzenes that contain at least two chlorines, only the seven reactions with the highest energy release took place. -from Authors
Hydrodechlorination of polychlorinated benzenes in the presence of a bimetallic catalyst in combination with a phase-transfer catalyst
Simagina,Stoyanova
, p. 38 - 39 (2001)
Bimetallic supported catalysts (Pd-Ni/C and Ni-Cu/C) in combination with a phase-transfer catalyst were found efficient and selective in the liquid-phase hydrodechlorination of polychlorinated benzenes under mild conditions.
Radiolytic reduction of hexachlorobenzene in surfactant solutions: A steady-state and pulse radiolysis study
Zacheis,Gray,Kamat
, p. 3401 - 3407 (2000)
Steady-state and pulse radiolysis experiments have been performed to gain insight into the mechanism of hexachlorobenzene (HCB) degradation in nonionic surfactant (Plurafac RA-40) solutions. This understanding is important for the environmental application of radiolysis to remediate soils contaminated with chlorinated aromatic compounds or to treat surfactant solution wastes from soil washing processes. Steady-state experiments showed that, after an applied dose of 50 kGy, reductive dechlorination of HCB to trichlorobenzene occurs under reducing conditions. Under oxidizing conditions at the same dose, reductive dechlorination proceeds more slowly to yield tetrachlorobenzene. Radiolytic experiments on the surfactant alone showed that the reaction rate constant between hydroxyl radicals and RA-40 (1.09 x 109 M-1 s-1) was nearly 2 orders of magnitude higher than that between hydrated electrons and RA-40 (2.0 x 107 M-1 s-1). Reaction kinetics analysis indicates efficient hydroxyl radical scavenging by surfactant molecules and the production of secondary surfactant radicals, which are reductive in nature. Thus, we observe HCB dechlorination in surfactant solutions even under strongly oxidizing conditions. Steady-state and pulse radiolysis experiments have been performed to gain insight into the mechanism of hexachlorobenzene (HCB) degradation in nonionic surfactant (Plurafac RA-40) solutions. This understanding is important for the environmental application of radiolysis to remediate soils contaminated with chlorinated aromatic compounds or to treat surfactant solution wastes from soil washing processes. Steady-state experiments showed that, after an applied dose of 50 kGy, reductive dechlorination of HCB to trichlorobenzene occurs under reducing conditions. Under oxidizing conditions at the same dose, reductive dechlorination proceeds more slowly to yield tetrachlorobenzene. Radiolytic experiments on the surfactant alone showed that the reaction rate constant between hydroxyl radicals and RA-40 (1.09 × 109 M-1 s-1) was nearly 2 orders of magnitude higher than that between hydrated electrons and RA-40 (2.0 × 107 M-1 s-1). Reaction kinetics analysis indicates efficient hydroxyl radical scavenging by surfactant molecules and the production of secondary surfactant radicals, which are reductive in nature. Thus, we observe HCB dechlorination in surfactant solutions even under strongly oxidizing conditions.
Iron(iii)porphyrin electrocatalyzed enantioselective carbon-chloride bond cleavage of hexachlorocyclohexanes (HCHs): Combined experimental investigation and theoretical calculations
Liang, Xu,Li, Minzhi,Mack, John,Lobb, Kevin,Zhu, Weihua
, p. 11470 - 11476 (2018)
Enantioselective electrocatalysis of α-, β-, γ- and δ-hexachlorocyclohexanes (HCHs) by tetrakis-pentafluorophenyl-Fe(iii)porphyrin is described. The first example of the combined use of electrochemical measurements and theoretical calculations to determine the mechanism of the enantioselective C-Cl bond cleavage of the electrocatalysis is reported. The electrochemical measurements demonstrate that the reactivity of the HCHs follows the order γ-HCH > α-HCH > δ-HCH > β-HCH. Steric considerations and a molecular orbital theory approach can be used to rationalize the enantioselective nature of the catalysis based on the ease of approach of each Cl atom to the central Fe(i) ion and a consideration of the nodes on the C-Cl bonds that weaken these bonds in a manner that results in bond cleavage and the formation of an Fe-Cl bond.
Direct Stereoselective β-Arylation of Enol Ethers by a Decarboxylative Heck-Type Reaction
Hachem, Mahmoud,Hoarau, Christophe,Schneider, Cédric
, (2020/04/15)
Despite remarkable advances to promote regio- and stereoselective decarboxylative arylation of inactivated olefins with benzoic acid derivatives, methodologies involving hetero-substituted alkenes are still lacking. Herein, PdII-catalyzed decarboxylative Heck coupling of α-alkoxyacrylates with (hetero)aryl carboxylic acids for the stereocontrolled production of (Z)-β-heteroarylated vinyl ethers is reported. This methodology offers a rational and step-economical route to the synthesis of attractive β-arylated α-alkoxy α,β-unsaturated carboxylates family which emerged as a relevant class of building blocks with different applications. Mechanistically, whereas electron rich benzoic acids undergo a PdII-catalyzed decarboxylation, electron-deficient substrates proceed through silver(I)-mediated decarboxylation, explaining thus the formation of stereoisomers (E) and (Z) of β-arylated vinyl ethers in presence of these latter.
