3547-04-4Relevant academic research and scientific papers
Indium Tribromide-Catalysed Transfer-Hydrogenation: Expanding the Scope of the Hydrogenation and of the Regiodivergent DH or HD Addition to Alkenes
Li, Luomo,Hilt, Gerhard
supporting information, p. 11221 - 11225 (2021/06/25)
The transfer-hydrogenation as well as the regioselective and regiodivergent addition of H?D from regiospecific deuterated dihydroaromatic compounds to a variety of 1,1-di- and trisubstituted alkenes was realised with InBr3 in dichloro(m)ethane. In comparison with the previously reported BF3?Et2O-catalysed process, electron-deficient aryl-substituents can be applied reliably and thereby several restrictions could be lifted, and new types of substrates could be transformed successfully in hydrodeuterogenation as well as deuterohydrogenation transfer-hydrogenation reactions.
Carbon-based leaving group in substitution reactions: Functionalization of sp3-hybridized quaternary and tertiary benzylic carbon centers
Mahoney, Stuart J.,Lou, Tiantong,Bondarenko, Ganna,Fillion, Eric
, p. 3474 - 3477 (2012/09/05)
Lewis acid promoted substitution reactions employing Meldrum's acid and 5-methyl Meldrum's acid as carbon-based leaving groups are described which transform unstrained quaternary and tertiary benzylic Csp 3-Csp3 bonds into Csp3-X bonds (X = C, H, N). Importantly, this reaction has a broad scope in terms of both suitable substrates and nucleophiles with good to excellent yields obtained (typically >90%).
Enhanced reactivity of hydrophobic vitamin B12 towards the dechlorination of DDT in ionic liquid
Jabbar, Md. Abdul,Shimakoshi, Hisashi,Hisaeda, Yoshio
, p. 1653 - 1655 (2008/02/07)
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.
Facile and catalytic degradation method of DDT using Pd/C-Et3N system under ambient pressure and temperature
Monguchi, Yasunari,Kume, Akira,Sajiki, Hironao
, p. 8384 - 8392 (2007/10/03)
The catalytic degradation method of p,p′-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its regioisomer o,p′-DDT [1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane] using the Pd/C-Et3N system under ambient hydrogen pressure and temperature was established. The presence of Et3N was necessary for the quick and complete breakdown of DDT. The independent degradation study of two intermediates, p,p′-DDD [2,2-bis(p-chlorophenyl)-1,1-dichloroethane] and p,p′-DDE [2,2-bis(p-chlorophenyl)-1,1-dichloroethylene] using GC-MS let us to speculate the degradation pathway of p,p′-DDT. In the initial phase of the reaction, p,p′-DDT degradation splits into two ways: a dehydrochlorination pathway and a hydrodechlorination pathway. In each pathway, reaction starts from an aliphatic moiety and subsequent hydrodechlorination from the benzene moieties takes place in a stepwise manner. The former pathway leads to the formation of 1,1-diphenylethane and the latter leads to the formation of 1,1-dichloro-2,2-diphenylethane. These diphenylethane analogs, which are less toxic compared with p,p′-DDT, are terminal degradation products in our system. The distinctive features of our catalytic degradation method of DDTs are reliability, simplicity, efficiency, and inexpensiveness.
Zinc metal assisted hydro-de-halogenation of DDT into DDEthane under sonic conditions
Pasha,Nagaraja
, p. 1747 - 1748 (2007/10/03)
An efficient method for the hydro-de-halogenation of DDT to 1,1-bis (p-chlorophenyl)ethane (DDEthane) exclusively by a simple reaction using commercial zinc dust, is reported. The rate of the reaction is enhanced by irradiating at 35 KHz in a sonic bath at 25°C.
Electrochemical reduction and oxidation of DDT
Merica, Simona G.,Jedral, Wojceich,Lait, Susan,Keech, Peter,Bunce, Nigel J.
, p. 1281 - 1287 (2007/10/03)
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.
Activation conditions play a key role in the activity of zeolite CaY: NMR and product studies of Bronsted acidity
Kao, Hsien-Ming,Grey, Clare P.,Pitchumani, Kasi,Lakshminarasimhan,Ramamurthy
, p. 5627 - 5638 (2007/10/03)
CaY, activated under different conditions, was characterized with 1H, 31P, and 1H/27A] double resonance MAS NMR. The 1H MAS NMR spectra of CaY, calcined in an oven at 500 °C, shows resonances from H2O (bound to Ca2+ and the zeolite framework), CaOH+, aluminum hydroxides, silanols, and Bronsted acid sites. No evidence for Lewis acidity is observed on adsorption of trimethylphosphine, and an estimate of ≈16 Bronsted acid sites per unit cell is obtained for this sample. CaY activated in an oven at higher temperatures contains less water, but all the other species are still present. In contrast, CaY activated by slow ramping of the temperature under vacuum to 500 or 600 °C shows a much lower concentration of Bronsted acid sites (1/unit cell). Again, no evidence for Lewis acidity was observed. These NMR results have been utilized to understand the very different product distributions that are observed for reactions of 1,1- and 1,2-diarylethylenes in zeolite CaY activated in an oven (in air) and under vacuum. Samples with high concentrations of Bronsted acid sites react stoichiometrically with these sites, yielding diarylalkanes. At low concentrations, the Bronsted acid sites can act catalytically resulting in isomerization reactions.
Electrolytic Dechlorination of DDT In a Bicontinuous Microemulsion
Schweizer, Silvia,Rusling, James F.,Huang, Qingdong
, p. 961 - 970 (2007/10/03)
Electrolytic reduction in a bicontinuous microemulsion of surfactant, oil, and water removed aliphatic and aromatic chlorines from DDT. Microemulsions of didodecyldimethylammonium bromide/dodecane/water used with graphite felt cathodes provided a less expensive, less toxic approach to DDT electrolysis compared to using conventional organic solvents and metal electrodes. Good rates of aliphatic dechlorination were achieved by applying -1 V vs. Ag/AgBr and using the catalyst Co(bpy)32+, but the best yield (34 percent in 3 hr) of the fully dechlorinated hydrocarbon 1,1-diphenylethane was achieved by using -2 V with oxygen in the reaction medium.
PULSE MICROREACTOR PESTICIDES HYDRODECHLORINATION
Weiss, A. H.,LaPierre, R. B.
, p. 111 - 122 (2007/10/02)
Catalytic hydrodechlorination of chlorinated pesticides and other environmentally chlorinated materials into lower chlorine content compounds has been studied in a pulse microreactor .Chlorine can be catalytically removed and replaced by hydrogen to prduce partially chlorinated intermediates as well as completely dechlorinated hydrocarbons.Intermediates are equivalent to some of those obtained by natural degradation.The pulse microreactor is a simple technique to predict both product composition and reaction severity required for laboratory scale preparation of such degradation products.
