2642-80-0Relevant articles and documents
Enhanced reactivity of hydrophobic vitamin B12 towards the dechlorination of DDT in ionic liquid
Jabbar, Md. Abdul,Shimakoshi, Hisashi,Hisaeda, Yoshio
, p. 1653 - 1655 (2007)
The electrolytic reductive dechlorination of 1,1-bis(p-chlorophenyl)-2,2,2- trichloroethane (DDT) in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) in the presence of a cobalamin derivative afforded 1,1′-(ethylidene)bis(4-chlorobenzene) (DDO) and 1,1′-(ethenylidene)bis(4-chlorobenzene) (DDNU) with 1,1′-(2- chloroethylidene)bis(4-chlorobenzene) (DDMS); the enhanced reactivity, as well as the recyclability of the cobalamin derivative catalyst in IL, makes the present system more efficient for the development of "green" technologies. The Royal Society of Chemistry.
Electrochemical reduction and oxidation of DDT
Merica, Simona G.,Jedral, Wojceich,Lait, Susan,Keech, Peter,Bunce, Nigel J.
, p. 1281 - 1287 (1999)
Electrolysis has been studied as a possible method to treat DDT wastes. In methanol, the major process was dehydrochlorination to DDE followed by further reduction. In an aqueous emulsion containing 1% heptane and 0.1% Triton SP-175, DDT was reduced at a deposited lead electrode with sodium sulphate as the supporting electrolyte by sequential hydrodechlorination of the aliphatic chlorine atoms. An excellent material balance was achieved, but the current efficiency was poor, even at low current densities. Electrooxidation of DDT was also investigated; in aqueous solutions or emulsion, little oxidation occurred because of competing oxidation of water at the highly positive potentials needed to oxidize DDT. In acetonitrile, electrooxidation occurred with high current efficiency by way of 'electrochemical combustion' of DDT and its intermediate oxidation products to CO2. We conclude that development of an electrolytic technology for destroying DDT wastes is unlikely.
Chemoselective Homologation-Deoxygenation Strategy Enabling the Direct Conversion of Carbonyls into (n+1)-Halomethyl-Alkanes
Citarella, Andrea,Holzer, Wolfgang,Ielo, Laura,Langer, Thierry,Miele, Margherita,Pace, Vittorio,Urban, Ernst,Zehl, Martin
supporting information, p. 7629 - 7634 (2020/10/12)
The sequential installation of a carbenoid and a hydride into a carbonyl, furnishing halomethyl alkyl derivatives, is reported. Despite the employment of carbenoids as nucleophiles in reactions with carbon-centered electrophiles, sp3-type alkyl halides remain elusive materials for selective one-carbon homologations. Our tactic levers on using carbonyls as starting materials and enables uniformly high yields and chemocontrol. The tactic is flexible and is not limited to carbenoids. Also, diverse carbanion-like species can act as nucleophiles, thus making it of general applicability.
Synthesis of a B12-BODIPY dyad for B12-inspired photochemical transformations of a trichloromethylated organic compound
Anai, Yuki,Shichijo, Keita,Fujitsuka, Mamoru,Hisaeda, Yoshio,Shimakoshi, Hisashi
supporting information, p. 11945 - 11948 (2020/10/15)
A B12complex-BODIPY dyad was synthesized by peripheral modification of cobalamin derivatives. The photophysical properties of the dyad were investigated by UV-vis, PL, and transient absorption spectroscopy. A visible light-driven dechlorination reaction of a trichlorinated organic compound, DDT, was reported. The dyad showed efficient catalysis for dechlorination under N2with turnover numbers of over 220 for the reaction. One-pot syntheses of an ester and amide from DDT and benzotrichloride were also achieved using the dyad under air.
Rh(iii)-Catalysed solvent-free hydrodehalogenation of alkyl halides by tertiary silanes
Almenara,Azpeitia,Garralda,Huertos
supporting information, p. 16225 - 16231 (2018/11/30)
Efficient catalytic reduction of CDCl3 and other alkyl halides, including persistent organic pollutants, by different tertiary silanes using the unsaturated silyl-hydrido-Rh(iii) complex {Rh(H)[SiMe2(o-C6H4SMe)](PPh3)2}[BArF4] as a pre-catalyst is accomplished. The reactions are performed in a solvent-free manner. On account of experimental evidence, a simplified catalytic cycle is suggested for the hydrodehalogenation of CDCl3.
Enhanced photocatalytic activity of a B12-based catalyst co-photosensitized by TiO2 and Ru(II) towards dechlorination
Sun, Ying,Zhang, Wei,Ma, Tian-Yi,Zhang, Yu,Shimakoshi, Hisashi,Hisaeda, Yoshio,Song, Xi-Ming
, p. 662 - 670 (2018/01/17)
A novel hybrid photocatalyst denoted as B12-TiO2-Ru(ii) was prepared by co-immobilizing a B12 derivative and trisbipyridine ruthenium (Ru(bpy)32+) on the surface of a mesoporous anatase TiO2 microspheres and was characterized by DRS, XRD, SEM and BET et al. By using the hybrid photocatalyst, DDT was completely didechlorinated and a small part of tridechlorinated product was also detected in the presence of TEOA only after 30 min of visible light irradiation. Under simulated sunlight, the hybrid exhibited a significantly enhanced photocatalytic activity for dechlorination compared with B12-TiO2 under the same condition or itself under visible light irradiation due to the additivity in the contribution of UV and visible part of the sunlight to the electron transfer. In addition, this hybrid catalyst can be easily reused without loss of catalytic efficiency. This is the first report on a B12-based photocatalyst co-sensitized by two photosensitizers with wide spectral response.
Significant enhancement of visible light photocatalytic activity of the hybrid B12-PIL/rGO in the presence of Ru(bpy)32+ for DDT dehalogenation
Sun, Ying,Zhang, Wei,Tong, Jian,Zhang, Yu,Wu, Shuyao,Liu, Daliang,Shimakoshi, Hisashi,Hisaeda, Yoshio,Song, Xi-Ming
, p. 19197 - 19204 (2017/04/10)
A new B12-PIL/rGO hybrid was prepared successfully through immobilizing a B12 derivative on the surface of poly(ionic liquid) (PIL)-modified reduced graphene oxide (rGO) by electrostatic attraction and π-π stacking attraction among the different components. The hybrid catalyst showed an enhanced photocatalytic activity in the presence of Ru(bpy)32+ for 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) dechlorination with ～100% conversion. Especially, the yield of didechlorinated products could reach 78% after 1 h of visible light irradiation, which should be attributed to a synergistic effect of B12, rGO and PIL in B12-PIL/rGO, including their respective catalytic performance, the excellent electron transport of rGO and the concentration of DDT and 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD) on the surface of B12-PIL/rGO. Furthermore, the hybrid catalyst was easily recycled for use without obvious loss of catalytic activity.
Supramolecular system composed of B12 model complex and organic photosensitizer: Impact of the corrin framework of B12 on the visible-light-driven dechlorination without the use of noble metals
Tahara, Keishiro,Mikuriya, Kumiko,Masuko, Takahiro,Kikuchi, Jun-Ichi,Hisaeda, Yoshio
, p. 141 - 150 (2016/02/09)
The visible-light-driven dechlorination system without the use of a noble metal has been developed. We screened the combination of cobalt catalysts having square-planar monoanionic ligands (hydrophobic B12 model complex 1/imine-oxime type complex 2) and typical red dyes (Rose Bengal 3/Rhodamine B 4/Nile Red 5) for the construction of a dehalogenation system via a noble-metal-free and visible-light-driven process. The combination of the hydrophobic B12 model complex 1 and Rose Bengal 3 exhibited the highest catalytic activity to 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) to form the monodechlorinated compound, 1,1-bis(4-chlorophenyl)-2,2-dichloroethane, as the major product. The prolonged photocatalysis of DDT by the B12-Rose Bengal system afforded the tri-dechlorinated compound, trans-4,4′-dichlorostilbene, as the major product. Furthermore, we investigated the mechanism of the dehalogenation cycle using various methods such as UV-vis spectroscopy and laser flash photolysis. Finally, we clarified the advantage of using the hydrophobic B12 model complex 1 as an electron acceptor as well as a cobalt catalyst in the organic dye-involved photocatalysis.
Electrochemical dechlorination of 4,4′-(2,2,2-trichloroethane-1,1-diyl)bis(chlorobenzene) (DDT) at silver cathodes
McGuire, Caitlyn M.,Peters, Dennis G.
, p. 423 - 430 (2014/12/10)
Cyclic voltammetry and controlled-potential (bulk) electrolysis have been employed to investigate the reduction of 4,4′-(2,2,2-trichloroethane-1,1-diyl)bis(chlorobenzene) (DDT) at silver cathodes in dimethylformamide (DMF) containing 0.050 M tetramethylammonium tetrafluoroborate (TMABF4). In addition, this work has been extended to the individual reductions of two degradation products, namely 4,4′-(2,2-dichloroethane-1,1-diyl)bis(chlorobenzene) (DDD) and 4,4′-(ethene-1,1-diyl)bis(chlorobenzene) (DDNU). At a scan rate of 100 mV s-1, cyclic voltammograms for irreversible reduction of DDT at a silver electrode exhibit four prominent cathodic peaks in DMF and CH3CN, and three prominent cathodic peaks in DMSO. On the other hand, reduction of DDD and DDNU at silver in DMF-0.050 M TMABF4displays four and two irreversible peaks, respectively. Carbon-chlorine bonds of the -CCl3moiety of DDT and of the -CHCl2moiety of DDD are reduced more easily at silver than at glassy carbon. Bulk electrolyses of DDT at a silver gauze cathode in DMF-0.050 M TMABF4afford a potential-dependent mixture of products that includes DDD, DDNU, 4,4′-(2,2-dichloroethene-1,1-diyl)bis(chlorobenzene) (DDE), 4,4′-(2-chloroethene-1,1-diyl)bis(chlorobenzene) (DDMU), 4,4′-(2-chloroethane-1,1-diyl)bis(chlorobenzene) (DDMS), 1-chloro-4-(1-phenylvinyl)benzene (PVB), 1,1′-diphenylethylene (DPE), and 1,1′-ethylidenebisbenzene (EBB). However, at more negative potentials, the principal products are completely dechlorinated DPE and EBB. Dechlorination of DDT at silver appears to proceed via a series of steps involving carbanion intermediates arising from direct reduction of alkyl and aryl carbon-chlorine bonds along with hydroxide-promoted E2 elimination of chloride. When DMF-d7was used as solvent, no evidence for deuterium atom incorporation into any product was seen, which indicates that radical intermediates do not play a significant role in the reduction of DDT.
Dechlorination of DDT catalyzed by visible-light-driven system composed of vitamin B12 derivative and Rhodamine B
Tahara, Keishiro,Mikuriya, Kumiko,Masuko, Takahiro,Kikuchi, Jun-Ichi,Hisaeda, Yoshio
, p. 135 - 141 (2013/05/08)
The visible-light-driven dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2- trichloroethane (DDT) was carried out in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate and Rhodamine B. DDT was successfully dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD) as the mono-dechlorinated product upon visible light irradiation with a tungsten lamp (λ > 440 nm). Upon prolonged visible light irradiation to DDT, DDMU (1-chloro-2,2-bis(4-chlorophenyl)ethylene), DDMS (1-chloro-2,2-bis(4-chlorophenyl)ethane) and DCS (trans-4,4′- dichlorostilbene) were obtained as the di- and tri-dechlorinated products. The use of the photostable organic sensitizer enabled prolonged photocatalysis via a noble-metal-free process. The vitamin B12 derivative was replaced by an imine/oxime-type cobalt complex although the cobalt complex system showed a lower catalytic activity than the B12 derivative system. The dechlorination mechanism in the B12-Rhodamin B system was investigated by various methods such as UV-vis absorption and fluorescence quenching. Copyright
