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In this study, carbon materials with different dimensions, including the typical one-dimensional (1D) carbon nanotube (CNT), two-dimensional (2D) graphene (GF), and three-dimensional (3D) activated carbon (AC), were investigated as a support for Pt catalysts for the selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB) to 3,4-dichloroaniline (3,4-DCAN). Notably, the Pt/CNT catalyst with the lowest dimension exhibited the best conversion of 3,4-DCNB under mild reaction conditions, followed by Pt/GF. Comprehensive characterizations, including XRD, TEM, XPS, and in situ CO DRIFTS, reveal that the dimension of carbon supports plays an important role in the particle size and electronic properties of Pt species, consequently affecting the catalytic performances of Pt catalysts. According to the results, electron-deficient Pt particles with small sizes are more favorable for the hydrogenation of 3,4-DCNB to 3,4-DCAN. In addition, dynamic tests and in situ DRIFTS of 3,4-DCNB indicated that the carbonaceous supports will largely influence the adsorption and activation capacity of the Pt catalysts, so that Pt loaded on CNT and GF are superior to that on the AC. We believe this study will provide good guidance for designing efficient carbon-supported metal catalysts for selective hydrogenation. [ABSTRACT FROM AUTHOR]

The sequencing electroreduction-electrooxidation process has emerged as a promising approach for the degradation of the chloronitrobenzenes (CNBs) due to its elimination of electro-withdrawing groups in the reduction process, facilitating further removal in the subsequent oxidation process. Herein, we developed a cathode consisting of atom Pd on a Ti plate, which enabled the electro-generation of atomic hydrogen (H*) and the efficient electrocatalytic activation of H 2 O 2 to hydroxyl radical (•OH). Cyclic voltammetry (CV) curves and electron spin resonance (ESR) spectra verified the existence of H* and •OH. The electroreduction-electrooxidation system achieved 94.7% of 20 mg L−1 2,4-DCNB removal with a relatively low H 2 O 2 addition (5 mM). Moreover, the inhibition rate of Photobacterium phosphoreum in the effluent decreased from 95% to 52% after the sequencing electroreduction-electrooxidation processes. It was further revealed that the H* dominated the electroreduction process and triggered the electrooxidation process. Our work sheds light on the effective removal of electron-withdrawing groups substituted aromatic contaminants from water and wastewater. [Display omitted] • A sequencing electroreduction-electrooxidation system was driven by H*. • Efficient 2,4-DCNB removal (94.7%) was achieved in the obtained system. • The toxicity of the intermediates was significantly reduced after the operation. • The system acquires relatively low dosage of H 2 O 2 and low energy consumption. [ABSTRACT FROM AUTHOR]

ABSTRACT Diaphorobacter sp. strain JS3051 utilizes 2,3-dichloronitrobenzene (23DCNB), a toxic anthropogenic compound, as the sole carbon, nitrogen, and energy source for growth, but the metabolic pathway and its origins are unknown. Here, we establish that a gene cluster (dcb), encoding a Nag-like dioxygenase, is responsible for the initial oxidation of the 23DCNB molecule. The 2,3-dichloronitrobenzene dioxygenase system (DcbAaAbAcAd) catalyzes conversion of 23DCNB to 3,4-dichlorocatechol (34DCC). Site-directed mutagenesis studies indicated that residue 204 of DcbAc is crucial for the substrate specificity of 23DCNB dioxygenase. The presence of glutamic acid at position 204 of 23DCNB dioxygenase is unique among Nag-like dioxygenases. Genetic, biochemical, and structural evidence indicate that the 23DCNB dioxygenase is more closely related to 2-nitrotoluene dioxygenase from Acidovorax sp. strain JS42 than to the 34DCNB dioxygenase from Diaphorobacter sp. strain JS3050, which was isolated from the same site as strain JS3051. A gene cluster (dcc) encoding the enzymes for 34DCC catabolism, homologous to a clc operon in Pseudomonas knackmussii strain B13, is also on the chromosome at a distance of 2.5 Mb from the dcb genes. Heterologously expressed DccA catalyzed ring cleavage of 34DCC with high affinity and catalytic efficiency. This work not only establishes the molecular mechanism for 23DCNB mineralization, but also enhances the understanding of the recent evolution of the catabolic pathways for nitroarenes. IMPORTANCE Because anthropogenic nitroaromatic compounds have entered the biosphere relatively recently, exploration of the recently evolved catabolic pathways can provide clues for adaptive evolutionary mechanisms in bacteria. The concept that nitroarene dioxygenases shared a common ancestor with naphthalene dioxygenase is well established. But their phylogeny and how they evolved in response to novel nitroaromatic compounds are largely unknown. Elucidation of the molecular basis for 23DCNB degradation revealed that the catabolic pathways of two DCNB isomers in different isolates from the same site were derived from different recent origins. Integrating structural models of catalytic subunits and enzymatic activities data provided new insight about how recently modified enzymes were selected depending on the structure of new substrates. This study enhances understanding and prediction of adaptive evolution of catabolic pathways in bacteria in response to new chemicals.

The matching of the micro-dispersion method and the reaction kinetics is of the utmost importance for the fast and strongly exothermic nitration reaction. Taken as an example to discuss this issue, a synthesis of 3,4-dichloronitrobenzene via the nitration of o-dichlorobenzene with mixed acid of nitric acid and sulfuric acid was conducted in continuous-flow reactors in this work. Through combining the adiabatic reaction environment, the use of a micropacked-bed reactor, and introducing partial product circulation, it successfully achieved the matching of the micro-dispersion state and the reaction kinetic characteristics. The good two-phase dispersion state can be maintained throughout the micropacked-bed reactor and the reaction can be completed within 5 s with above 89% selectivity under adiabatic condition. Furthermore, the reaction activation energy was conveniently obtained by processing the temperature distribution data, providing a fundamental to realize a reliable design of the nitration reaction process with high efficiency and inherent safety. [ABSTRACT FROM AUTHOR]

35Cl NQR frequency and spin lattice relaxation time in 3,4‐dichloronitrobenzene have been measured as a function of temperature and pressure. Two NQR signals were observed in the temperature range 77 to 300 K and pressure up to 5.1 kbar at 300 K. The contributions to the relaxation from the torsional motion of the molecule and reorientational motion of the nitro group have been analyzed on the basis of the Woessner and Gutowsky model. The temperature dependence of the average torsional lifetimes of the molecules, transition probabilities, and the activation energy for the reorientation of the nitro group was estimated. The pressure dependence of the NQR frequency in 3,4‐Dichloronitrobenzene shows a nonlinear increase in NQR frequency with increase in pressure, indicating increased contribution from the static effects at higher pressures. A thermodynamic analysis of the data was carried out to determine the constant‐volume temperature coefficients of the NQR frequency. The spin–lattice relaxation was found to be weakly dependent on pressure. [ABSTRACT FROM AUTHOR]

Coupled bioelectrochemical system-upflow anaerobic sludge blanket (BES-UASB) was utilized for wastewater treatment containing 2,4-dichloronitrobenzene (DClNB). The results indicated that a proper voltage enhanced the DClNB reduction, however, over high voltage presented a negative impact (2.0 V). Synergistic effect of external voltage and anaerobic sludge was observed, and dechlorination efficiency reached 57.8 ± 5.4% in the coupled BES, which was higher than the sum of anaerobic sludge and electric system (48.2%). Moreover, the coupled system was more tolerant of high salinity and pollutant concentration. Dehydrogenase activity (DHA) was related to microbial electron transfer activity and DHA reached a maximum 453 ± 33 μgTF g−1VSS h−1 in the coupled reactor which was 1.6-fold that of the control, meanwhile, extracellular polymeric substances (EPS) content was significantly enhanced in the presence of external voltage. In summary, the coupled BES-UASB systems could be an alternative for removal of recalcitrant pollutants such as DClNB. [ABSTRACT FROM AUTHOR]

For enhanced dechlorination of 2,4-dichloronitrobenzene (2,4-DClNB), a coupled microbial electrosynthesis-upflow anaerobic sludge reactor (MES-UASB) was established, and the effect of cathode potential on the performance of combined process was investigated in this study. Results showed that a higher dechlorination efficiency of 78.5 ± 6.1% was achieved in the coupled MES-UASB at −660 mV, and the degradation rate of 4-chloroaniline (4-ClAn) reached 4.61 mg·L −1 ·d −1 within 120 h at −660 mV of cathode potential in batch experiments. The results of Illumina sequencing indicated that the biocathode operated at a lower potential favored the enrichment of dechlorination-related microbes such as Dehalobacter , Dehalococcoides and Anaeromyxobacter both in granular sludge and cathode biofilm. It could be speculated that a lower cathode potential is more feasible for the dechlorination of 2,4-DClNB due to the enrichment of dechlorination-related microbes as well as the production of electrons with higher energy for long-distance electron transfer (LDET). [ABSTRACT FROM AUTHOR]

In this study, bioelectrochemical-upflow anaerobic sludge blanket (BES-UASB) system was developed for treatment of 2,4-dichloronitrobenzen (DClNB) containing wastewater to investigate the effect of external voltage with different supplying modes. Results showed that 2,4-dichloroaniline (DClAN) was under detection limit in R1 (applied with intermittent voltage) and R2 (applied with continuous voltage) when the DClNB loading increased from 25 to 100 g m 3 d −1 (hydraulic retention time (HRT) was decreased from 24 to 6 h) while sudden accumulation of DClAN (1.7 mg L −1 ) was observed in R0 (control). Dechlorination efficiency (DE) decreased to 32.7%, 45.0% and 45.3% in R0, R1 and R2 when HRT was further shortened to 4 h. Microbial community analysis indicated the significant enrichment of dechlorination-related species in R1 and R2 compared with R0, e.g., Dehalobacter and Dehalococcoides . In summary, the BES-UASB system with intermittent voltage is an alternative process for efficient treatment of DClNB containing wastewater, and the energy input was reduced markedly. [ABSTRACT FROM AUTHOR]

Experimental data on nitro compound uptake, the intermediate product accumulation, and the corresponding amine compound generation were obtained on hydrogenating 3,4-dichloronitrobenzene over Pt/C catalyst in the gradient-free flow regime in the presence and absence of pyridine. In addition, a side reaction of dehalogenation was investigated. The role of pyridine admixture on every step of the process was analyzed and the rate of hydrogenation of the nitro compound was determined both in the presence and in the absence of inhibitor. [ABSTRACT FROM AUTHOR]

The stable (solid + liquid) phase equilibrium in ternary systems of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + ethanol and 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + n -propanol at three temperatures was determined by means of an isothermal solution saturation method under pressure p = 101.2 kPa. The isothermal phase diagrams of the two ternary systems were plotted on the basis of the experimental mutual solubility data. The equilibrium solids formed in the two systems were identified by Schreinemakers’ method of wet residues. It was found that each phase diagram included one co-saturated point, two co-saturated curves and three crystallization zones in the ternary systems of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + ethanol and 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + n -propanol. Two pure solid phases were formed in the studied systems, which were pure 2,3-dichloronitrobenzene and pure 3,4-dichloronitrobenzene. The crystallization zone of 3,4-dichloronitrobenzene was smaller than that of 2,3-dichloronitrobenzene at a given temperature, which showed that 2,3-dichloronitrobenzene could be easily separated from the solution. Furthermore, the solid–liquid phase diagrams were calculated by using NRTL model. The calculated phase diagrams agreed well with the experimental ones. Knowledge of (solid + liquid) phase equilibrium and ternary phase diagrams would be very valuable to design and optimize the solvent crystallization process of 2,3-dichloronitrobenzene and other crystallization processes involving the two ternary systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1:1 Fe/FeS 2 can accelerate the microbial reduction of 2,4-dichloronitrobenzene. • The methane production was drastically facilitated by 1:1 Fe/FeS 2 and MR-1. • The reciprocal interaction between FeS and microbial consortium was intensified. • Reducing bacteria of nitroaromatics and acetoclastic methanogen were enriched. The technology of integrating sulfidated zero-valent iron and functional anaerobic bacteria has been extensively explored to improve the removal efficiency of pollutants and enhance the performance of anaerobic microbial system. In this study, the simultaneous DCNB(2,4-dichloronitrobenzene) reduction and methane production by ball-milled 1:1 Fe0/FeS 2 (briefly, 1:1 Fe0/FeS 2), Shewanella oneidensis MR-1 and microbial consortium (MC) were firstly investigated. The result showed that the DCNB reduction was increased by 2.6 and 1.7 times in 1:1 Fe0/FeS 2 + MR-1 group compared to 1:1 Fe0/FeS 2 and MR-1, respectively, while it further increased by almost 2 times in 1:1 Fe0/FeS 2 + MC + MR-1 group as compared to that of 1:1 Fe0/FeS 2 + MR-1 group. Moreover, the methane production was drastically facilitated via the reciprocal interaction among FeS as the reaction product, MR-1 and MC. Dechlorination was not found, mainly due to the inability of 1:1 Fe0/FeS 2 and the inexistence of dechlorinating bacteria in original inoculum. Meanwhile, the microbial community was also changed, with genera like Eubacterium capable of reducing nitroaromatic compound and Methanosarcina as acetoclastic methanogen enriched by 1:1 Fe0/FeS 2 and MR-1. Therefore, fast DCNB reduction and methane production using 1:1 Fe0/FeS 2 in anaerobic microbial system, gives useful reference for both establishment of pollutant removal and biogas production. In conclusion, Fe0/FeS 2 , as a kind of sulfidated ZVI, is a good candidate for enhancing both pollutant degradation and CH 4 production in anaerobic wastewater treatment. [ABSTRACT FROM AUTHOR]

The solid–liquid phase equilibrium for ternary system of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + methanol were determined experimentally by the method of isothermal solution saturation at temperatures of 283.15 K, 293.15 K and 303.15 K under pressure of 101.3 kPa. According to the obtained solubility data, the isothermal phase diagrams of the system were constructed. At each temperature, there were two pure solid phases formed, which were confirmed by Schreinemakers' wet residue method and corresponded to pure 3,4-dichloronitrobenzene and pure 2,3-dichloronitrobenzene. The crystallization regions of pure 3,4-dichloronitrobenzene and pure 2,3-dichloronitrobenzene increased with decreasing in temperature. The crystalline region of 2,3-dichloronitrobenzene was larger than that of 3,4-dichloronitrobenzene at the same temperature, and increased rapidly as the temperature increase. The data of solid–liquid phase equilibrium were correlated with NRTL model and Wilson model. The calculated solubility data with NRTL model agreed well with the experimental values. The mutual solubility data and ternary phase diagrams for the system were of great significance for optimizing the purification procedure of 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene. [ABSTRACT FROM AUTHOR]

Among the mono- and dichloroanilines, 3,5-dichloroaniline (3,5-DCA) is the most potent nephrotoxicant in vivo and in vitro. However, the role of renal biotransformation in 3,5-DCA induced nephrotoxicity is unknown. The current study was designed to determine the in vitro nephrotoxic potential of 3,5-DCA in isolated renal cortical cells (IRCC) obtained from male Fischer 344 rats, and the role of renal bioactivation and oxidative stress in 3,5-DCA nephrotoxicity. IRCC (∼4 million cells/ml) from male rats were exposed to 3,5-DCA (0–1.0 mM) for up to 120 min. In IRCC, 3,5-DCA was cytotoxic at 1.0 mM by 60 min as evidenced by the increased release of lactate dehydrogenase (LDH), but 120 min was required for 3,5-DCA 0.5 mM to increase LDH release. In subsequent studies, IRCC were exposed to a pretreatment (antioxidant or enzyme inhibitor) prior to exposure to 3,5-DCA (1.0 mM) for 90 min. Cytotoxicity induced by 3,5-DCA was attenuated by pretreatment with inhibitors of flavin-containing monooxygenase (FMO; methimazole, N -octylamine), cytochrome P450 (CYP; piperonyl butoxide, metyrapone), or peroxidase (indomethacin, mercaptosuccinate) enzymes. Use of more selective CYP inhibitors suggested that the CYP 2C family contributed to 3,5-DCA bioactivation. Antioxidants (glutathione, N -acetyl- l -cysteine, α-tocopherol, ascorbate, pyruvate) also attenuated 3,5-DCA nephrotoxicity, but oxidized glutathione levels and the oxidized/reduced glutathione ratios were not increased. These results indicate that 3,5-DCA may be activated via several renal enzyme systems to toxic metabolites, and that free radicals, but not oxidative stress, contribute to 3,5-DCA induced nephrotoxicity in vitro. [ABSTRACT FROM AUTHOR]

The results for the degradation efficiency of 4-chloronitrobenzene (4-CNB) by various advanced oxidation processes in a batch mode using nano-structured titanium dioxide demonstrated the order of O/US/TiO > US/O > O/TiO > O > US/TiO > US. The utilized TiO nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, all processes obeyed pseudo-first order kinetics. Then, the effect of the main operational conditions including pH, ozone, initial 4-CNB concentration, TiO dosage and ultrasonic power on 4-CNB degradation was studied in the coupled O/US/TiO process as the most significant treatment method with a high synergistic effect. The optimal pH and TiO dosage were selected to be 9 and 50 mg/L owing to the efficient indirect attack of hydroxyl radicals and less screening effects of TiO particles on ultrasonic waves, respectively. By increasing the amount of O concentration and ultrasonic power, the degradation of 4-CNB was enhanced due to the more production of reactive oxygen species. However, the opposite trend was observed for 4-CNB concentration because the same amounts of generated oxidizing species under the identical experimental conditions had to degrade more organic pollutants and its degradation intermediates. Eventually, the total organic carbon (TOC) was utilized to monitor the mineralization of 4-CNB in the above-mentioned processes and the same results were obtained with lower rate constants compared to degradation rate constants. [ABSTRACT FROM AUTHOR]

Degradation of aqueous 3,4-dichloroaniline (3,4-DCA) was conducted in a novel dielectric barrier discharge (DBD) plasma reactor. The factors affecting the degradation efficiency of 3,4-DCA and the degradation mechanism of 3,4-DCA were investigated. The experimental results indicated that the degradation efficiency of 3,4-DCA increased with increasing input power intensity, and the degradation of 3,4-DCA by the novel DBD plasma reactor fitted pseudo-first-order kinetics. Higher degradation efficiency of 3,4-DCA was observed in acidic conditions. The degradation efficiency of 3,4-DCA, the removal rate of total organic carbon (TOC), and the detected Cl increased dramatically with adding Fe or Fe. Degradation of 3,4-DCA could be accelerated or inhibited in the presence of HO depending on the dosage. Several degradation intermediates of 3,4-DCA such as 1,2-dichlorobenzene, 2-chloro-1,4-benzoquinone, 3,4-dichlorophenyl isocyanate, 2-chlorohydroquinone, 3,4-dichloronitrobenzene, and 3,4-dichlorophenol were identified by gas chromatography mass spectrometry (GC-MS) analysis. Based on the identification of aromatic intermediates, acetic acid, formic acid, oxalic acid, and Cl released, a possible mineralization pathway of 3,4-DCA was proposed. [ABSTRACT FROM AUTHOR]

Mole fraction solubilities are reported for 1,4-dichloro-2-nitrobenzene dissolved in 24 organic solvents of varying polarity and hydrogen-bonding character. The experimental data are used to calculate Abraham solute descriptors. The calculated solute descriptors describe the experimental data to within an overall average standard deviation of 0.081 log units. Also reported in the manuscript are Abraham model solute descriptors for both 3,4-dichloro-1-nitrobenzene and 2,3-dichloro-1-nitrobenzene based on published literature data. [ABSTRACT FROM AUTHOR]

The solubilities of 2,3-dichloronitrobenzenein aqueous solutionsof methanol and ethanol with various concentrations were determinedat temperatures ranging from (278.15 to 303.15) K under atmosphericpressure of 0.1 MPa. The solubility of 2,3-dichloronitrobenzene increaseswith increments in both temperature and mass fraction of methanolor ethanol. The solubility data were correlated by five models, whichare the Jouyban–Acree model, van't Hoff–Acree model,modified Apelblat–Acree model, Ma model, and Sun model. Thecalculated solubility using the Jouyban–Acree model shows betteragreement with the experimental data than those by the other models.The thermodynamic properties, molar dissolution enthalpy, molar dissolutionentropy, and Gibbs free energy change of dissolution process of 2,3-dichloronitrobenzenein two mixed solvents were calculated. [ABSTRACT FROM AUTHOR]

Highlights: [•] The saturated vapor pressure of pure 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene was measured. [•] The isobaric vapor–liquid equilibrium data were measured for 3,4-dichloronitrobenzene+2,3-dichloronitrobenzene system. [•] The vapor–liquid equilibrium data were correlated with Wilson, NRTL and UNIQUAC models. [Copyright &y& Elsevier]

Thesolubility of 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzenein ethyl acetate, tetrachloromethane, cyclohexane, hexane, heptane,1-propanol, 2-propanol, and 1-butanol were measured experimentallyunder temperatures of (278.15 to 303.15) K by employing the gravimetricmethod. The solubility of 3,4-dichloronitrobenzene or 2,3-dichloronitrobenzenein all organic solvents studied increases with increasing in temperature.Four models, the modified Apelblat equation, λhequation, Wilson model, and nonrandom two-liquid (NRTL) model, wereemployed to correlate the measured solubility. Results indicated thatthe modified Apelblat equation was the better model than the othermodels. The solubility data would be very useful for optimizing thepurification process of 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzeneon the industrial scale. [ABSTRACT FROM AUTHOR]

Phototransformation is considered one of the most key factors affecting the fate of pesticides. Therefore, our study focused on photocatalytic degradation of three selected pesticide derivatives: trifluralin (1), clodinafop-propargyl (2), and 1,2-dichloro-4-nitrobenzene (3). The degradation was carried out in acetonitrile/water medium in the presence of titanium dioxide (TiO²) under continuous purging of atmospheric air. The course of degradation was followed by thin-layer chromatography and gas chromatography-mass spectrometry techniques. Electron ionization mass spectrometry was used to identify the degradation species. GC-MS analysis indicates the formation of several intermediate products which have been characterized on the basis of molecular ion, mass fragmentation pattern, and comparison with NIST library. The photocatalytic degradation of pesticides of different chemical structures manifested distinctly different degradation mechanism. The major routes for the degradation of pesticides were found to be (a) dealkylation, dehalogenation, and decarboxylation, (b) hydroxylation, (c) oxidation of side chain, if present, (d) isomerization and cyclization, (e) cleavage of alkoxy bond, and (f) reduction of triple bond to double bond and nitro group to amino. [ABSTRACT FROM AUTHOR]

Abstract: Micro-sized anthracite particles (ANTCs) were used as natural adsorbent for efficient removal of nitrobenzene (NB), 1,3-dinitrobenzene (DNB) and 2,4-dichloronitrobenzene (DCNB) from polluted water samples. Results indicated that the adsorption of NB, DNB and DCNB was rapid and reached a steady state after 3min. Effects of solution pH, amount of adsorbent, contact time, ionic strength and reusability on the adsorption capability of the ANTC were investigated. Experimental results showed that the removal efficiency is independent of pH and ionic strength of the test solution. The adsorption isotherms were well described by the Langmuir model and kinetics of removal processes were obeyed the pseudo-second-order mechanism. The adsorbed amounts of NB, DNB and DCNB were determined by high performance liquid chromatographic (HPLC) measurements before and after the removal process. The loading capacity of ANTC for adsorption of NB, DNB and DCNB was determined to be 0.577, 0.672 and 0.853mg/g, respectively. This study showed the potential ability of ANTC as an efficient natural adsorbent for removal of NB, DNB and DCNB from industrial wastewater samples. [Copyright &y& Elsevier]

The solubilities of 3,4-dichloronitrobenzenein methanol, ethanol,and liquid mixtures (methanol + water, ethanol + water) were measuredin the temperature range of (278.15 to 303.15) K at 101.3 kPa by gaschromatography. The solubility of 3,4-dichloronitrobenzene in thebinary mixed solvents increased with both increasing temperature andmass fraction of organic solvents. The measured solubility was correlatedby the van’t Hoff equation, the modified Apelblat equation,and the λhequation. The correlated resultsindicated that the calculated solubility using the modified Apelblatequation had a closer agreement with the experimental data than thoseusing the other two models. According to the measured solubility,the thermodynamic properties of dissolution of 3,4-dichloronitrobenzene,including the Gibbs free energy change of solution, molar enthalpyof dissolution, and molar entropy of dissolution, were calculatedby using the modified Apelblat model. [ABSTRACT FROM AUTHOR]

Abstract: A series of Pd-only catalysts supported on activated carbon pretreated with HNO3 or EDTA-2Na for liquid phase selective hydrogenation 3,4-dichloronitrobenzene (DCNB) to corresponding 3,4-dichloroaniline (DCAN) are investigated. Characterization of the catalysts is performed by N2 adsorption/desorption, TPD, XRD and TPD techniques. The selectivity to DCAN is not only correlate with the Pd particle average size, but also correlate with distribution of Pd particles sizes. The surface groups of activated carbon can influence the average size and distribution of Pd particles. Pretreated activated carbon with HNO3, forms various oxygen-containing groups on the surface, results in large average size but wide-distributed Pd particles. On the contrast, pretreated activated carbon with EDTA-2Na results in large average size and narrow-distributed of Pd particles simultaneously. More than 60% Pd particles sizes are distributed in the 20–30nm range of the 2% Pd loading catalyst pretreated with 1M EDTA-2Na, of which the selectivity to DCAN is up to 99.61%. [Copyright &y& Elsevier]

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Abstract: The standard (p°=0.1MPa) molar enthalpies of formation of 2,4-, 2,5-, 3,4- and 3,5-dichloronitrobenzene isomers, in the crystalline state, at T =298.15K, were derived from the standard (p°=0.1MPa) massic energies of combustion, in oxygen, at T =298.15K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the four isomers, at T =298.15K, were obtained by high-temperature Calvet microcalorimetry. From the determined experimental results, the values of the gaseous standard (p°=0.1MPa) molar enthalpies of formation were derived. The gas-phase enthalpies of formation of all the six chloronitrobenzene isomers were also estimated by the Cox scheme and by computational thermochemistry methods and compared with the available experimental values. [Copyright &y& Elsevier]

Experimental and computational searches for the crystal structures of the five commercially available isomers of dichloronitrobenzene and 3,4-dinitrochlorobenzene were performed to assess the relationship between functional group interactions and steric requirements in determining the solid forms. Experimentally, this resulted in the first crystal structure determination of 2,4-dichloronitrobenzene, two solvates of 3,4-dichloronitrobenzene and one of 3,4-dinitrochlorobenzene. Additionally, low temperature redeterminations of the crystal structures were obtained for 2,5-dichloronitrobenzene, 3,4-dichloronitrobenzene, and both the β- and γ-forms of 3,4-dinitrochlorobenzene. The searches for energetically feasible structures of each of these compounds showed a wide variety of distributions leading to varying degrees of clarity of prediction of the solid state behavior. These range from 2,3-dichloronitrobenzene, which only adopts the crystal structure that was clearly the most thermodynamically stable of all five isomers, through complex systems, which show a range of low energy minima indicating possible polymorphism and solvate formation, to 2,4-dichloronitrobenzene, which can conformationally distort and adopts a complicated Z′ = 2 crystal structure. [ABSTRACT FROM AUTHOR]

The article examines the carcinogenicity and chronic toxicity of 1,4-dichloro-2-nitrobenzene in rats and mice. A dose-related increase in combined incidences of renal cell adenomas and carcinomas was noted. Signs of chronic toxicity were characterized by centrilobular hyperthrophy of hepatocytes with nuclear atypia in mice.

Evaluates the cytotoxic effects of two chemical sensitizers, dinitrofluorobenzene (DNFB) and dichloronitrobenzene (DCNB) on the metabolism and viability of a purified population of skin dendritic cells (FSDC). Impact of DNFB on the cellular metabolism of a dendritic cell line derived from mouse skin; Observation of cell death by the incubation of DNFB; Factors that led to the death of FSDC.

Unlike the closely related chemical dinitrochlorobenzene (DNCB), which is a very strong contact allergen, dichloronitrobenzene (DCNB) has been widely regarded as a non-allergen and, as such, a useful control for its strongly sensitizing counterpart. Nevertheless, it is still an organic chemical species readily capable of penetrating skin and, rather than being regarded as completely inert, it has even been suggested to react with the immune system in such a way that it induces specific tolerance to its chemical structure. We investigated whether DCNB was in reality a non-allergen, or rather merely a weak contact sensitizer. In both a rigorously conducted guinea pig maximization test and in a modified murine local lymph node assay, DCNB was demonstrated to possess weak sensitizing activity. On this basis, DCNB cannot be regarded as inert with respect to contact allergic potential, and is therefore inappropriate as a negative control in studies of skin sensitization. [ABSTRACT FROM AUTHOR]

The current study was designed to explore the in vitro nephrotoxic potential of four 3,5-dichloroaniline (3,5-DCA) metabolites (3,5-dichloroacetanilide, 3,5-DCAA; 3,5-dichlorophenylhydroxylamine, 3,5-DCPHA; 2-amino-4,6-dichlorophenol, 2-A-4,6-DCP; 3,5-dichloronitrobenzene, 3,5-DCNB) and to determine the renal metabolism of 3,5-DCA in vitro. In cytotoxicity testing, isolated kidney cells (IKC) from male Fischer 344 rats (~4 million/mL, 3 mL) were exposed to a metabolite (0–1.5 mM; up to 90 min) or vehicle. Of these metabolites, 3,5-DCPHA was the most potent nephrotoxicant, with 3,5-DCNB intermediate in nephrotoxic potential. 2-A-4,6-DCP and 3,5-DCAA were not cytotoxic. In separate experiments, 3,5-DCNB cytotoxicity was reduced by pretreating IKC with antioxidants and cytochrome P450, flavin monooxygenase and peroxidase inhibitors, while 3,5-DCPHA cytotoxicity was attenuated by two nucleophilic antioxidants (glutathione and N-acetyl-L-cysteine). Incubation of IKC with 3,5-DCA (0.5–1.0 mM, 90 min) produced only 3,5-DCAA and 3,5-DCNB as detectable metabolites. These data suggest that 3,5-DCNB and 3,5-DCPHA are potential nephrotoxic metabolites and may contribute to 3,5-DCA induced nephrotoxicity in vivo. In addition, the kidney can bioactivate 3,5-DCNB to toxic metabolites, and 3,5-DCPHA appears to generate reactive metabolites to contribute to 3,5-DCA nephrotoxicity. In vitro, N-oxidation of 3,5-DCA appears to be the primary mechanism of bioactivation of 3,5-DCA to nephrotoxic metabolites. [ABSTRACT FROM AUTHOR]

• Effective DCNB reduction could be achieved by MR-1 assisted with AHQ/RGO. • The AHQ/RGO mediated DCNB bioreduction enhanced by 7.7-fold (k value). • Cytochromes and reductases played key roles in DCNB reduction by MR-1. • Multiple ETP were involved in the AHQ/RGO mediated DCNB bioreduction. • A synergetic effect between AHQ/RGO and outer membrane protein was observed. The slow anaerobic reduction rate of 2,5-dichloronitrobenzene (DCNB) is a bottleneck during its biotreatment. In this study, the process and mechanism of enhanced DCNB bioreduction by a 2-amino-3-hydroxy-anthraquinone/reduced grapheme oxide (AHQ/RGO) binary nanocomposite in the presence of Shewanella oneidensis MR-1 (MR-1) are reported. AHQ/RGO was prepared using a one-step covalent combination method under mild conditions, and the as-prepared binary nanocomposite was further characterized by SEM, TEM, AFM, EA, UV–Vis, XRD, XPS, FTIR and electrochemical analyses. The results of catalytic assays showed that enhanced DCNB bioreduction to 2,5-dichloroaniline could be achieved in the presence of 30 mg/L AHQ/RGO and the k (h−1) value of the AHQ/RGO-supplemented system is 7.7- and 4.2-fold greater than that of the control and GO-supplemented systems, respectively. Moreover, molecular studies showed that the genes encoding cytochromes and reductases (especially yceJ and azoR) play key roles during the reduction of DCNB by MR-1 cells and multiple electron transfer pathways are involved during AHQ/RGO-mediated DCNB bioreduction. In addition, a synergistic effect between AHQ/RGO and outer membrane proteins of MR-1 was confirmed by mutant assays and is likely responsible for the catalytic performance of AHQ/RGO. This work provides a potential application of strain MR-1 and AHQ/RGO in enhancing the treatment of DCNB-containing wastewater. [ABSTRACT FROM AUTHOR]

The solvate structure of 3,4-dichloro-1-nitro­benzene with aniline, 2C6H3Cl2NO2·C6H7N, is reported. Ribbons of 3,4-dichloro­nitro­benzene, formed by Cl⋯Cl and N—O⋯Cl inter­actions, are linked together via N—H⋯O hydrogen bonds with aniline into an undulating two-dimensional sheet. [ABSTRACT FROM AUTHOR]

Female infertility involves an emotional impact for the woman, often leading to a state of anxiety and low self-esteem. The assisted reproduction techniques (ART) are used to overcome the problem of infertility. In a first step of the in vitro fertilization therapy women are subjected to an ovarian stimulation protocol to obtain mature oocytes, which will result in competent oocytes necessary for fertilization to occur. Ovarian stimulation, however, subjects the women to a high physical and psychological stress, thus being essential to improve ART and to find biomarkers of dysfunction and fertility. GSH is an important antioxidant, and is also used in detoxification reactions, catalysed by glutathione S -transferases (GST). In the present work, we have investigated the involvement of GST in follicular maturation. Patients with fertility problems and oocyte donors were recruited for the study. From each woman follicles at two stages of maturation were extracted at the preovulatory stage. Follicular fluid was separated from the oocyte by centrifugation and used as the enzyme source. GST activity was determined based on its conjugation with 3,4-dichloronitrobenzene and the assay was adapted to a 96-well microplate reader. The absorbance was represented against the incubation time and the curves were adjusted to linearity (R 2 >0.990). Results showed that in both donors and patients GST activity was significantly lower in mature oocytes compared to small ones. These results suggest that GST may play a role in the follicle maturation by detoxifying xenobiotics, thus contributing to the normal development of the oocyte. Supported by FIS/FEDER (PI11/02559), Gobierno Vasco (Dep. Educación, Universiades e Investigación, IT687-13), and UPV/EHU (CLUMBER UFI11/20 and PES13/58). The work was approved by the Ethics Committee of the UPV/EHU (CEISH/96/2011/RUIZLARREA), and performed according to the UPV/EHU and IVI-Bilbao agreement (Ref. 2012/01). [ABSTRACT FROM AUTHOR]

The solvate structure of 3,4-dichloro-1-nitro­benzene with 1,4-dioxane, C6H3Cl2NO2·0.25C4H8N2, is reported. The asymmetric unit comprises two independent 3,4-dichloro-1-nitro­benzene mol­ecules and half of a 1,4-dioxane mol­ecule, the solvent molecule being disposed about a centre of inversion. Double chains of 3,4-dichloro-1-nitro­benzene are linked by Cl⋯Cl inter­actions and 1,4-dioxane mol­ecules via C—H⋯O hydrogen bonds into a two-dimensional sheet. [ABSTRACT FROM AUTHOR]

Within this study all three monochloronitrobenzenes were identified and quantified in water of the German Bight of the North Sea. The concentrations ranged from <0.02 to 8.9 ng/L. The latter high value was found in the estuary of the River Elbe, though. Additionally, 2,5-dichloronitrobenzene and 3,4-dichloronitrobenzene were identified and quantified. The concentrations of these compounds ranged from <0.05 to 7.7 ng/L. The major path of input for the chloronitrobenzenes to thismarine area is the River Elbe. A method for quantification is described. [ABSTRACT FROM AUTHOR]