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Showing papers on "Nitrobenzene published in 2009"


Journal ArticleDOI
TL;DR: A novel relationship between the initiation of *OH and the surface-OH2+ group on the modified catalyst is established based on the synergetic effect between homogeneous and heterogeneous reaction systems.
Abstract: Comparative experiments have been performed to investigate the degradation efficiency of nitrobenzene and the removal efficiency of TOC in aqueous solution bythe processes of ceramic honeycomb supported different metals (Fe, Ni, and Zn) catalytic ozonation, indicating that the modification with metals can enhance the activity of ceramic honeycomb for the catalytic ozonation of nitrobenzene, and the loading percentage of metal and the metallicity respectively presents a positive influence on the degradation of nitrobenzene. The degradation efficiency of nitrobenzene is determined by the initiation of hydroxyl radical (*OH) according to a good linear correlation in all the processes of modified ceramic honeycomb catalytic ozonation at the different loading percentages of metals. The modification of ceramic honeycomb with metals results in the conversion of the pH at the point of zero charge (pHpzc) and the evolution of surface groups. Divergence from the conventional phenomenon, the enhancement mechanism of ozone decomposition on the modified ceramic honeycomb with metals is proposed due to the basic attractive forces of electrostatic forces or/and hydrogen bonding. Consequently, a novel relationship between the initiation of *OH and the surface-OH2+ group on the modified catalyst is established based on the synergetic effect between homogeneous and heterogeneous reaction systems.

199 citations


Journal ArticleDOI
TL;DR: Compared to those of conventional anaerobic biological methods for nitrobenzene removal, the required dosage of organic cosubstrate was significantly reduced in this system.
Abstract: Nitrobenzene occurs as a pollutant in wastewaters originating from numerous industrial and agricultural activities. It needs to be removed prior to discharge to sewage treatment works because of its high toxicity and persistence. In this study, we investigated the use of a bioelectrochemical system (BES) to remove nitrobenzene at a cathode coupled to microbial oxidation of acetate at an anode. Effective removal of nitrobenzene at rates up to 1.29 +/- 0.04 mol m(-3) TCC d(-1) (total cathodic compartment, TCC) was achieved with concomitant energy recovery. Correspondingly, the formation rate for the reduction product aniline was 1.14 +/- 0.03 mol m(-3) TCC d(-1). Nitrobenzene removal and aniline formation rates were significantly enhanced when the BES was supplied with power, reaching 8.57 +/- 0.03 and 6.68 +/- 0.03 mol m(-3) TCC d(-1), respectively, at an energy consumption of 17.06 +/- 0.16 W m(-3) TCC (current density at 59.5 A m(-3) TCC). Compared to those of conventional anaerobic biological methods for nitrobenzene removal, the required dosage of organic cosubstrate was significantly reduced in this system. Although aniline was always identified as the major product of nitrobenzene reduction at the cathode of BES in this study, the Coulombic efficiencies of nitrobenzene removal and aniline formation were dependent on the current density of the BES.

192 citations


Journal ArticleDOI
TL;DR: Experimental results have shown that to develop a "green process" the constituents of essential oils, d-limonene, p-cymene, terpinenes, phellandrene, are the most appropriate solvents.

141 citations


Journal ArticleDOI
TL;DR: In this article, the selective hydrogenation of nitrobenzene (NB) over Ni/gamma-Al2O3 catalysts was investigated using different media of dense phase CO2, ethanol, and n-hexane.

139 citations


Journal ArticleDOI
TL;DR: In this article, the performance of 1.5% Pd supported on hydrotalcite, MgO and γ-Al2O3 catalysts was investigated for the hydrogenation of nitrobenzene.
Abstract: Vapor phase hydrogenation of nitrobenzene is reported on 1 wt.% Pd supported on hydrotalcite, MgO and γ-Al2O3 catalysts. The catalysts were prepared in the laboratory using a wet impregnation method and were characterized by XRD, BET surface area, TPR, TEM, XPS and CO chemisorption studies. The conversion of nitrobenzene was studied in the temperature region of 498–573 K and compared on all the catalysts. An impressive catalytic performance of nitrobenzene conversion was observed on hydrotalcite supported Pd catalyst. CO chemisorption and TEM results prove that palladium disperses better on hydrotalcite supports when compared with other conventional supports such as MgO and γ-Al2O3, which is responsible for the high conversion of nitrobenzene.

133 citations


Journal ArticleDOI
04 Mar 2009-Langmuir
TL;DR: Findings show that under certain conditions aryl films formed from the reduction of diazonium salts are more strongly bonded to gold surfaces compared to the thiol analogue.
Abstract: The reduction of diazonium salts to produce aryl films on surfaces has expanded in application from carbon electrodes to a variety of conducting materials. The increasing interest in this method for modifying gold surfaces has motivated us to directly compare the structure and stability of nitrobenzene films derived from diazonium salts with monolayers formed from the corresponding thiol. We employ spectroscopic and microscopic techniques to characterize the structure and thickness of the as-formed layers. As a means of assessing stability, the nitrobenzene films were subjected to rigorous sonication, refluxing solvents, and chemical displacement by octadecanethiol. Infrared reflection−absorption spectroscopy and electrochemical blocking were used to assess the stabilities of the films generated by the two methods. Sonication and refluxing both remove more material from the diazonium-derived film relative to the thiol monolayer. However, a significant amount of each layer remains bonded to the surface fol...

126 citations


Journal ArticleDOI
TL;DR: The investigation of the enhancement mechanism confirms that the modification by loading Cu causes changes of density of surface hydroxyl groups, pH(PZC), and /pH - pH(ZC)/, resulting in the acceleration initiation of *OH which can promote the degradation of nitrobenzene.
Abstract: The use of cordierite or Cu-cordierite for heterogeneous catalytic ozonation enhances significantly the degradation efficiency and the TOC removal of nitrobenzene in aqueous solution relative to oz...

126 citations


Journal ArticleDOI
TL;DR: In this article, the degradation efficiencies of nitrobenzene in aqueous solution were investigated by semi-continuous experiments in the processes of ozone alone, ozone/ceramic honeycomb (CH) and ozone/modified ceramic honeycomb(MCH).
Abstract: The degradation efficiencies of nitrobenzene in aqueous solution were investigated by semi-continuous experiments in the processes of ozone alone, ozone/ceramic honeycomb (CH) and ozone/modified ceramic honeycomb (MCH). MCH with 1.0% Mn and 0.5% Cu had more pronounced catalytic ability than CH to accelerate the degradation of nitrobenzene, to increase the utilization efficiency of ozone, to improve the concentrations of hydrogen peroxide (H2O2) formation and hydroxyl radical ( OH) initiation, and to enhance the removal efficiency of TOC. The modification process of CH with the metals enhanced the density of surface hydroxyl groups, which determines the initiation of OH from ozone decomposition and the generation of intermediate species on heterogeneous catalytic surface, yielding the acceleration of the degradation of nitrobenzene in aqueous solution. Possible reaction mechanism of ozone with heterogeneous catalytic surface in aqueous solution was proposed, and the formation mechanism of H2O2 and OH was also discussed according to the combined reactions in heterogeneous and homogeneous catalytic systems.

113 citations


Journal ArticleDOI
TL;DR: In this paper, a series of Ru/SBA-15 catalysts (0.5 − 6.0 ) are prepared by impregnation method and the catalytic activities were evaluated for the vapor phase hydrogenation of nitrobenzene.
Abstract: A series of Ru/SBA-15 catalysts (0.5–6.0 wt%) are prepared by impregnation method. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), CO-chemisorption, surface area and pore-size distribution measurements. The catalytic activities were evaluated for the vapor phase hydrogenation of nitrobenzene. The dispersion measured by CO-uptake values suggests decrease in dispersion with increasing Ru loading on SBA-15. These findings are well supported by the crystallite size measured from XRD and TEM measurements. XPS study reveals the formation of Ru0 after reduction at 573 K for 3 h. The catalysts exhibit high conversion/selectivity at 4.5 wt% Ru loading during hydrogenation reaction. The particle size measured from CO-chemisorption and TEM analysis related to the TOF during the hydrogenation reaction. Ru/SBA-15 catalysts are found to show higher conversion/selectivities during hydrogenation of nitrobenzene than Ru/SiO2 and Ru/Al2O3 catalysts.

86 citations


Journal ArticleDOI
TL;DR: In this paper, carbon supported nickel (1%, w/w) catalysts have been prepared by deposition-precipitation with urea, and three supports were treated with HNO3+H2SO4 to generate oxygen-containing surface groups that served as anchoring sites for Ni introduction.
Abstract: Carbon supported nickel (1%, w/w) catalysts have been prepared by deposition–precipitation with urea. Two structured, i.e. carbon nanofibers (CNF, 129 m2 g−1) and nanospheres (CNS, 15 m2 g−1), and one unstructured, i.e. activated carbon (AC, 686 m2 g−1), supports were used. The three supports were treated with HNO3 + H2SO4 to generate oxygen-containing surface groups that served as anchoring sites for Ni introduction. The supports and Ni catalysts have been characterized by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), temperature-programmed reduction (TPR), temperature-programmed decomposition (TPD), Raman spectroscopy, N2 adsorption–desorption and acid/base titrations, which have established distinct morphological, graphitic and porous characteristics. CNS and CNF exhibited significant graphitic character when compared with AC, which was essentially microporous in contrast to mesoporous CNF and CNS. Pore volumes were lowered after the HNO3 + H2SO4 treatment, a result that we associate with the incorporation of surface acidity. TPR of the three Ni/C samples resulted in low (620–630 K) and high (823–910 K) temperature hydrogen consumption due to a combined reduction of the Ni precursor and partial decomposition of surface acid groups. Surface area weighted mean Ni particle diameters (post-activation at 623 K) were in the range 7.7–10.4 nm. The three catalysts were tested in the gas phase (T = 523 K) hydrogenation of nitrobenzene to aniline. Application of pseudo-first order kinetics has delivered the following sequence of increasing specific (per mNi2) activity: Ni/CNF < Ni/CNS < Ni/AC. Our results demonstrate that nitrobenzene hydrogenation is essentially insensitive to Ni particle size and the higher specific rate delivered by Ni/AC can be attributed to greater surface acidity that serves to enhance nitrobenzene activation.

79 citations


Journal ArticleDOI
21 Apr 2009-Langmuir
TL;DR: It is shown that the polarity of the solvent influences the thermal stability of the gel, the hydrogen-bonding network, and finally the structure of gel network.
Abstract: The solvent effect on organogel formation in nitrobenzene and chlorobenzene using 1,2-O-(1-ethylpropylidene)-α-d-glucofuranose (1) as the gelator is presented. Fourier transform infrared (FTIR) spectroscopy revealed that hydrogen bonding between the molecules of gelator 1 is the main driving force for gelator self-aggregation. The gels are characterized by different hydrogen-bonding patterns, which are reflected in a different microstructure of the networks. The morphology of fibers of nitrobenzene organogel consists of straight, rod-like, and thinner fibers, in comparison to the elongated but generally not straight and thicker fibers in chlorobenzene organogel. The thermal stability of gels also differs, and the ΔH is equal to 50.1 and 65.0 kJ/mol for nitrobenzene and chlorobenzene gels, respectively. The properties of the gels reported here were compared to benzene and toluene gels of 1 presented in previous work and correlated with different solvent parameters: e, δ, and ET(30). We have shown that the ...

Journal ArticleDOI
TL;DR: It was found that the fluidized-bed Fenton process could remove 30-65% of iron via iron crystallization onto the carriers' surface which could lead to a significant reduction in ferric hydroxide sludge production.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the micro-amounts of strontium and barium extracted by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polyethylene glycol PEG 600 (L) has been investigated.
Abstract: Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polyethylene glycol PEG 600 (L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, H2L2+, ML2+ and MHL3+ (M2+ = Sr2+, Ba2+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that in water-saturated nitrobenzene the stability constant of the BaL2+ cationic complex species is essentially higher than that of the complex SrL2+.

Journal Article
TL;DR: In this article, the authors investigated the extraction of micro amounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H + B - ) in the presence of N, N, n', N'- tetraisobutyl - 2, 6 - dipicolinamide [T(iBu)DPA, L] has been investigated.
Abstract: Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H + B - ) in the presence of N, N, N', N'- tetraisobutyl - 2, 6 - dipicolinamide [T(iBu)DPA, L] has been investigated. The equilibrium data have been explained assuming that the cations HL + , HL + 2 , ML 3 2 + and ML 3 3 + (M 3+ = Eu 3+ , Am 3+ ) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

Journal ArticleDOI
TL;DR: In this paper, Nitroarenes are reduced to the corresponding N-arylhydroxylamines with high selectivity using Zn dust in a CO2/H2O system under mild conditions.

Journal ArticleDOI
TL;DR: In this paper, Nitrobenzene was reduced to aniline in an acidic aqueous suspension of titanium(IV) oxide photocatalyst in the presence of oxalic acid as a hole scavenger and the anilin...
Abstract: Nitrobenzene was effectively and selectively reduced to aniline in an acidic aqueous suspension of titanium(IV) oxide photocatalyst in the presence of oxalic acid as a hole scavenger and the anilin...

Journal ArticleDOI
TL;DR: In this paper, a 1,4-butanediol to γ-butyrolactone reaction has been coupled with the hydrogenation of nitrobenzene to aniline in the vapor phase using a fixed bed reactor in the presence of Cu/MgO catalysts.

Journal ArticleDOI
TL;DR: Water miscible ionic liquids had various effects on the physiology of Clostridium sporogenes when tested as additives in culture media or reaction media for reduction of nitrobenzene.

Journal ArticleDOI
TL;DR: By using different concentrations of beta-CD and HP-beta-CD as extractants, nitrobenzene on active carbon has been desorbed statically and the desorbing of mechanism has been discussed.

Journal ArticleDOI
TL;DR: Experiments on the nitrobenzene degradation in different concentrations of NaCl and in the presence of phenol or aniline demonstrated that polyurethane-immobilized Z1 exhibited higher tolerance toward salinity and toxic chemicals than those of free cells.

Journal ArticleDOI
Chunli Zheng1, Baocheng Qu1, Jing Wang1, Jiti Zhou1, Hong Lu1 
TL;DR: Strain Z3 completely degraded nitrobenzene with initial concentration of 100, 150, 200, and 250 mg L(-1) within 70, 96, 120 and 196 h, respectively, and could be an excellent candidate for the bio-treatment of nitro Benzene industrial wastewaters with high salinity.

Journal ArticleDOI
TL;DR: In this paper, a controlled production of carbon nanospheres (CNS) via pyrolysis of benzene, aniline and nitrobenzene at 950°C has been examined.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the extraction of micro amounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of octyl-phenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide (classical CMPO, L) has been investigated.
Abstract: Abstract Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of octyl-phenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide (“classical” CMPO, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2+, CaL2+, CaL22+, CaL32+, SrL22+, SrL32+ and SrL42+ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

Journal ArticleDOI
TL;DR: In this article, the solvent extraction and liquid membrane studies on Ln(III)/An(III) separation using ethyl-bis-triazinylpyridine (Et-BTP) as the extractant were conducted.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the extraction of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide (DPBCMPO, L) has been investigated.
Abstract: Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide (DPBCMPO, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2+, ML23+, ML33+ and ML43+ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that the stability constants of the corresponding complexes EuLn3+ and AmLn3+, where n = 2, 3, 4 and L is DPBCMPO, in water saturated nitrobenzene are comparable.

Journal ArticleDOI
TL;DR: The experimental results indicated that the presence of ceramic honeycomb catalyst significantly improved the degradation efficiency of nitrobenzene compared to the results from non-catalytic ozonation, and the adsorption of nitrosene on the catalytic surface has no significant effect on its degradation efficiency.

Journal ArticleDOI
TL;DR: The results suggested that the modification process promoted the catalytic activity of raw CH catalyst, namely the impregnation of metals (Mn, Cu and K) maybe enhance the initiation of hydroxyl radical (OH).

Journal ArticleDOI
TL;DR: In this article, the authors investigated the extraction of micro amounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of TEtDPA, L. The equilibrium data have been explained assuming that the cations HL+, HL23, ML23+, ML23+ and ML33+ (M3+ = Eu3+, Am3+) are extracted into the organic phase.
Abstract: Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of N,N,N′,N′-tetraethyl-2,6-dipicolinamide (TEtDPA, L) has been investigated. The equilibrium data have been explained assuming that the cations HL+, HL23+, ML23+ and ML33+ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that the stability constants of the corresponding complexes EuLn,org3+ and AmLn,org3+, where n = 2, 3 and L is TEtDPA, in the mentioned medium are comparable.

Journal ArticleDOI
TL;DR: In this paper, aniline was produced from in-situhydrogenation of nitrobenzene with hydrogen generated from methanol, or transfer hydrogenation of n-methylation of N-methylated n-dimethylaniline over a pretreated Raney-Ni® catalyst.
Abstract: A route for the direct synthesis of N,N-dimethylaniline from nitrobenzene and methanol was developed through the sequential coupling of the hydrogen production from methanol, hydrogenation of nitrobenzene to produce aniline, and N-methylation of aniline over a pretreated Raney-Ni® catalyst (at 443 K in methanol). A high yield of N,N-dimethylaniline up to 98% was obtained by the proposed methodology. In this process, aniline was produced from in-situhydrogenation of nitrobenzene with hydrogen generated from methanol, or transfer hydrogenation of nitrobenzene with methanol as donor, while methanol acted as a hydrogen source, alkylating reagent and solvent, simultaneously. Additionally, a plausible mechanism of this one-pot reaction process has been described.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the extraction of micro amounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H + B- ) in the presence of N,N-dibutyl-N,N'-dimethyl-2-(2-dodecyloxyethyl)-malonamide (DBDMDDOEMA, L) has been investigated.
Abstract: Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H + B – ) in the presence of N,N'-dibutyl-N,N'-dimethyl-2-(2-dodecyloxyethyl)-malonamide (DBDMDDOEMA, L) has been investigated. The equilibrium data have been explained assuming that the cations HL2 , ML2 and ML3 (M 3+ = Eu 3+ , Am 3+ ) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that the stability constants of the corresponding complexes EuLn and AmLn , where n = 2,3 and L is DBDMDDOEMA, in water saturated nitrobenzene are comparable.