N:Dangerous for the enviro
132-64-9Relevant articles and documents
A Short Synthesis of Dibenzofurans and Dibenzothiophenes
Black, Michael,Cadogan, J. I. G.,McNab, Hamish
, p. 395 - 396 (1990)
An afficient synthesis of dibenzofurans and dibenzothiophenes from aryl salicylates is described, which involves a novel rearrangement-extrusion-cyclisation sequence of o-substituted phenoxyl and thiophenoxyl radicals.
Efficient synthesis of dibenzoxaborininols from diaryl ethers and their application to dibenzofuran synthesis
Niu, Liting,Yang, Haijun,Jiang, Yuyang,Fu, Hua
, p. 3625 - 3632 (2013)
A convenient and efficient method for the borylation of diaryl ethers leading to dibenzoxaborininols and the synthesis of dibenzofuran derivatives has been developed. The borylation involves the sequential three-step process: lithiation, borylation and hydrolysis. The synthesized dibenzoxaborininols could be readily transformed into dibenzofuran derivatives in good to excellent yields under palladium catalysis in the presence of iodine, and this is the first example for the formation of an aryl C-C bond from diarylborinic acids. Copyright
Thermal hydrogenolysis of dibenzo-p-dioxin and dibenzofuran
Cieplik, Mariusz K.,Epema, Onno J.,Louw, Robert
, p. 2792 - 2799 (2002)
The behaviour of dibenzo-p-dioxin (DD) and dibenzofuran (DF) was studied in flow reactors in an excess of hydrogen, at atmospheric or elevated pressure (up to 35 bar), in the temperature range 890-1262 K. The experiments at atmospheric pressure were performed with DF or DD as such, while at increased pressures the compounds were introduced as an admixture with benzene. DD gave CO, but also DF as an important product. The rates clearly depended on the hydrogen concentration, and were about an order of magnitude higher than that of the hydrodechlorination of chlorobenzene. The reaction apparently started with the fission of a C-O bond, induced by H atom attack. DF reacted much more slowly, to give CO and hydrocarbons, especially naphthalene and benzene. Its rate was insensitive to the concentration of H2, and the degradation has been interpreted as thermolysis, through C-O bond homolysis, isomerisation and fragmentation, primarily to naphthalene, and C2O as the intermediate to CO. The apparent resistance of DF to hydrogenolysis can be understood from its relatively favourable thermodynamic stability. The consequences for the behaviour of polychlorinated DDs and DFs under similar conditions - relevant for the possible application of thermal hydrogenolysis as a waste management technology - are also discussed briefly. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Supercritical water oxidation of a PCB of 3-chlorobiphenyl using hydrogen peroxide
Hatakeda, Kiyotaka,Ikushima, Yutaka,Ito, Shota,Saito, Norio,Sato, Osamu
, p. 245 - 246 (1997)
The supercritical water oxidation (SCWO) of a PCB of 3-chlorobiphenyl (1) was carried out at a temperature of 673 K and a pressure of 30 MPa with a flow reactor. The initial concentrations of (1) and hydrogen peroxide ranged from 1.84 X 10 -3 to 8.74 X 10 -2 M (1 M=1 mol dm -3), and 0.181 to 2.67 M, respectively. The decomposition of (1) was higher than 99.9% so long as hydrogen peroxide was stoichiometrically added.
A One-Pot Synthesis of Dibenzofurans from 6-Diazo-2-cyclohexenones
Zhao, Hua,Yang, Ke,Zheng, Hongyan,Ding, Ruichao,Yin, Fangjie,Wang, Ning,Li, Yun,Cheng, Bin,Wang, Huifei,Zhai, Hongbin
, p. 5744 - 5747 (2015)
A novel and efficient protocol for the rapid construction of dibenzofuran motifs from 6-diazo-2-cyclohexenone and ortho-haloiodobenzene has been developed. The process involves one-pot Pd-catalyzed cross-coupling/aromatization and Cu-catalyzed Ullmann coupling.
Visible-Light-Promoted Synthesis of Dibenzofuran Derivatives
Cho, Ji Young,Roh, Geum-Bee,Cho, Eun Jin
, p. 805 - 811 (2018)
Dibenzofurans are naturally occurring molecules that have received considerable attention for a variety of practical applications, such as in pharmaceuticals and electronic materials. Herein, an efficient and eco-friendly method for the synthesis of dibenzofuran derivatives via intramolecular C-O bond formation, which involves the in situ production of a diazonium salt, is described. The transformation requires a diazotizing agent and is promoted by the use of an organic photosensitizer under visible-light irradiation.
Prediction of polychlorinated dibenzofuran congener distribution from gas-phase phenol condensation pathways
Ryu, Jae-Yong,Mulholland, James A.,Oh, Jeong-Eun,Nakahata, Duane T.,Kim, Do-Hyong
, p. 1447 - 1455 (2004)
A model for predicting the distribution of dibenzofuran and polychlorinated dibenzofuran (PCDF) congeners from a distribution of phenols was developed. The model is based on a simplified chemical mechanism. Relative rate constants and reaction order with respect to phenol precursors were derived from experimental results using single phenols and equal molar mixtures of up to four phenols. For validation, experiments were performed at three temperatures using a distribution of phenol and 19 chlorinated phenols as measured in municipal waste incinerator exhaust gas. Comparison of experimental measurements and model predictions for PCDF isomer distributions and homologue pattern shows agreement within measurement uncertainty. The R-squared correlation coefficient exceeds 0.9 for all PCDF isomer distributions and the distribution of PCDF homologues. These results demonstrate that the distribution of dibenzofuran and the 135 PCDF congeners from gas-phase condensation of phenol and chlorinated phenols can be predicted from measurement of the distribution of phenol and the 19 chlorinated phenol congeners.
Mechanisms of dioxin formation from the high-temperature oxidation of 2-bromophenol
Evans, Catherine S.,Dellinger, Barry
, p. 2128 - 2134 (2005)
The homogeneous, gas-phase oxidative thermal degradation of 2-bromophenol was studied in a 1 cm i.d., fused silica flow reactor at a concentration of 88 ppm, reaction time of 2.0 s, over a temperature range from 300 to 1000 °C. Observed products in order of yield were dibenzo-p-dioxin (DD) > 4,6-dibromodibenzofuran (4,6-DBDF) > 4-monobromodibenzofuran (4-MCDF), dibenzofuran (DF), 1-monobromodibenzo-p-dioxin (1-MBDD), naphthalene, bromonaphthalene, 2,4-dibromophenol, 2,6-dibromophenol, phenol, bromobenzene, and benzene. This result is in contrast to the oxidation of 2-chlorophenol, where the major product is 4,6-dichlorodibenzofuran (4,6-DCDF). 4,6-DBDF was observed in high yields in contrast to our previous results for the pyrolysis of 2-bromophenol, where 4,6-DBDF was not detected. The increase in 4,6-DBDF yields is attributed to hydroxyl radical being the major chain carrier under oxidative conditions, which favors hydrogen-abstraction reactions that lead to formation of 4,6-DBDF. However, DD is still the highest yield product under oxidative conditions because of the relative ease of displacement of Br? in the ring-closure reaction.
Cubic nano-copper(I) oxides as reusable catalyst in consecutive decarboxylative C[sbnd]H arylation and carbonylation: rapid synthesis of carbonyl dibenzofurans
Pal, Rammyani,Chatterjee, Nivedita,Roy, Manas,Sarkar, Sabyasachi,Sarkar, Swarbhanu,Sen, Asish Kumar
, p. 4956 - 4960 (2016)
Consecutive chemo- and regio-selective decarboxylative C[sbnd]H arylation, followed by carbonylative C[sbnd]C coupling of aryl halide with isocyanide/alcohol was applied for the first time in one-step synthesis of carbonyl dibenzofurans with nanodomain cuprous oxide under aerobic condition. As a proof of concept, several novel dibenzofurans were synthesized from 2-(3-iodophenoxy)benzoic acid in good yield. The tandem protocol eliminates the use of excess catalysts, hazardous organic solvents, heavy metals like palladium or rhodium, ligands, oxidants, or external additives. More importantly, the cubic Cu(I) nanocatalyst can be recovered and recycled for three consecutive reactions without any significant loss of catalytic activity or any change in its morphology. Use of water as solvent and reusable catalyst makes the reaction environment friendly.
The thermodynamic properties of dibenzofuran
Chirico, R. D.,Gammon, B. E.,Knipmeyer, S. E.,Nguyen, A.,Strube, M. M.,et al.
, p. 1075 - 1096 (1990)
Measurements leading to the calculation of the ideal-gas thermodynamic properties for dibenzofuran are reported.Experimental methods included combustion calorimetry, adiabatic heat-capacity calorimetry, comparative, ebulliometry, inclined-piston manometry, and differential scanning calorimetry.Entropies, enthalpies, and Gibbs energies of formation were derived for the ideal gas for selected temperatures between 298.15 K and 720 K.The critical temperature and critical density were determined with a differential scanning calorimeter, and the critical pressure was derived.These are the first reported experimental critical properties for dibenzofuran.Measured combustion enthalpies, vapour pressures, critical properties, and ideal-gas entropies are compared with literature values.
