共查询到20条相似文献,搜索用时 15 毫秒
1.
A. V. Terent’ev V. V. Varfolomeeva A. K. Buryak 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2331-2335
Henry constants for the adsorption of o- and p-phenylenediamines on the surface of graphitized thermal carbon black within the temperature range 433–479 K were calculated
by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between
the nitrogen atom in aniline and isomeric phenylenediamines and the carbon atom of the basal face of graphite were determined.
It was shown that an intramolecular H bond influenced the geometry and adsorption properties of o-phenylenediamine. 相似文献
2.
《Journal of Molecular Catalysis #》1979,5(5):319-330
The rhodium cluster complex, Rh6(CO)16, has been found to catalyze the homogeneous reduction of nitrobenzene to aniline at temperatures above 80 °C in the presence of N,N-dimenthylbenzylamine, using any one of the following reducing gases: (1) H2/CO, (2) H2, (3)CO/H2O. The reductions are highly selective and aniline was the only product detected. The same result was obtained using Amberlyst A-21 resin beads which contained polymerbound N,N-dimethylbenzylamine moieties which, in turn, immobilize the rhodium clusters. It was shown, by using D2O, and following deuterium incorporation into the resulting aniline, that the water is the source of hydrogen when CO/H2O was used. When nitrobenzene is absent, this catalyst system promotes the water—gas shift reaction. Unlike aromatic nitro groups, aliphatic nitro groups were not reduced. However, the water—gas shift reaction was catalyzed. The kinetics of aniline formation were first order in nitrobenzene and the effect of pressure on the reaction is described. Use of the resin catalyst led to lower rates and a remarkably air sensitive catalyst system relative to the homogeneous reactions. 相似文献
3.
S. N. Yashkin D. A. Svetlov Yu. N. Klimochkin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(10):1783-1790
The thermodynamic characteristics of adsorption (TCA) for isomeric molecules of mono-, di-, tri-, and tetrafluoroadamantanes
were determined for the first time experimentally and by molecular statistics on the surface of graphitized thermal black
(GTB). The parameters of atom-atom potential function of pair intermolecular interaction (φ(r)) for F atoms included in fluoroadamantanes with C atoms on the basal face of graphite were calculated for the first time
within an atom-atom approximation of the semi-empirical molecular statistical theory of adsorption. The adsorption non-equivalence
of F atoms in various positions of an adamantane framework, a consequence of the mutual effect of atoms in a framework molecule,
was determined. On the basis of the definite TCA values, the conclusion was drawn as to the possibility of isolation of isomeric
fluoroadamantanes under the conditions of gas-adsorption chromatography on GTB. 相似文献
4.
S. N. Yashkin E. A. Yashkina D. A. Svetlov Yu. N. Klimochkin 《Russian Chemical Bulletin》2013,62(5):1286-1292
The thermodynamic characteristics of adsorption (TCA) of isomeric molecules of methyl- and dimethylaminoadamantanes on the surface of the basis face of graphite were determined experimentally and calculated by the molecular statistical method. A relationship between the geometric structure of adsorbate molecules and the values of their TCA on graphitized thermal carbon black was established. The data obtained were used for the gas chromatographic identification of the amination products of a mixture of Z,E-isomers of 1,4-dimethyladamantane and 1,3-dimethyladamantane. 相似文献
5.
Xuanping Wang Longbin Li Mingzhu Shi Yiqi Wang Guodong Xu Kai Yuan Peipei Zhu Mengning Ding Yiwang Chen 《Chemical science》2022,13(39):11639
Aqueous electrochemical nitroarene reduction reaction using H2O as the sustainable hydrogen source is an emerging technology to produce functionalized anilines. However, the development of low-cost electrocatalysts and the fundamental mechanistic understanding of the selective NO-RR still remain challenging. Herein, self-supporting hierarchical nanosheets consisting of high-density Co9S8/Ni3S2 heterojunctions on Ni foam (Co9S8/Ni3S2-NF) are constructed via an in situ self-template strategy. With combined advantages of high-loading, high surface exposure, efficient conductivity and unique electronic structure of the Co9S8/Ni3S2 interface, the as-prepared Co9S8/Ni3S2-NF exhibits efficient electrocatalytic NO-RR performance, including up to 99.0% conversion and 96.0% selectivity towards aniline, and outstanding functional group tolerance. Mechanistic investigations and theoretical calculations reveal that electron transfer from Ni3S2 to Co9S8 is beneficial for the co-adsorption of H2O and nitrobenzene molecules at the interfacial sites, promoting the formation of active hydrogen and subsequent reduction of nitrobenzene. Additionally, the interfacial charge transfer breaks the symmetry of two active Co sites at the Co9S8/Ni3S2 interface, which markedly reduces the energy barrier for reduction of nitrobenzene to aniline. This work offers a successful example for the interfacial engineering of metal sulfide-based heterojunctions with excellent electrocatalytic nitroarene reduction performance, and also paves the way for the in-depth understanding of the corresponding mechanism.Electrons transfer from Ni3S2 to Co9S8 in Co9S8/Ni3S2 heterojunctions through their interface, which is favourable for the adsorption of H2O and nitrobenzene onto Co sites for the formation of H* and further protonation of nitrobenzene. 相似文献
6.
Bartosz Zarychta Anna Piecyk‐Mizgaa Zdzisaw Daszkiewicz Jacek Zaleski 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(8):o515-o517
The structures of the two title isomeric compounds (systematic names: N‐methyl‐N,2‐dinitroaniline and N‐methyl‐N,3‐dinitroaniline, both C7H7N3O4) are slightly different because they exhibit different steric hindrances and hydrogen‐bonding environments. The aromatic rings are planar. The –N(Me)NO2 and –NO2 groups are not coplanar with the rings. Comparison of the geometric parameters of the ortho, meta and para isomers together with those of N‐methyl‐N‐phenylnitramine suggests that the position of the nitro group has a strong influence on the aromatic ring distortion. The crystal packing is stabilized by weak C—H⋯O hydrogen bonds to the nitramine group. 相似文献
7.
Tris(acetylacetonato)ruthenium(III)(Ru(acac)3) was synthesized with RuCl3·nH2O and acetylacetone as raw materials. The structure of Ru(acac)3 was identified by FI-IR, 1H NMR, 13C NMR, and elemental analysis. It was used in the catalytic hydrogen transfer hydrogenation of nitrobenzene with sodium formate as hydrogen donor. The effects of reaction conditions on the process, such as temperature, time, dosage of catalyst, and kinds of hydrogen donor, were investigated. The optimal reaction parameters were determined as follows: 80 °C, 4.0 h, the substrate nitrobenzene 20 mL, sodium formate 27.20 g, Ru(acac)3 0.96 g, the conversion of nitrobenzene is 100.0 %, the yield of aniline and the selectivity to aniline are 96.65 %. The reaction mechanism is proposed and analyzed. It exhibited excellent catalytic properties in the hydrogen transfer hydrogenation of nitrobenzene to aniline. 相似文献
8.
J. H. Henriquez-Román M. Sancy M. A. Páez L. Padilla-Campos J. H. Zagal C. M. Rangel G. E. Thompson 《Journal of Solid State Electrochemistry》2005,9(7):504-511
The inhibiting action of aniline and its derivatives on the corrosion of copper in hydrochloric acid has been investigated, with emphasis on the role of substituents. With this purpose five different anilines were selected: aniline, p-chloro aniline, p-nitro aniline, p-methoxy and p-methyl aniline. The electrochemical and gravimetric results, obtained in the absence and presence of different concentrations of inhibitors, revealed that aniline reduces the corrosion of copper, with a critical concentration of 10–2 M. Furthermore, the interaction energy calculated as Gads gave a value of 4.2 kcal mol–1 indicating physisorption of the organic compound at the copper surface. The results have also shown that substituents, either electron donors (–CH3, –OCH3) or, electron acceptors (–NO2, –Cl) in para position, decrease the inhibition action of aniline. A theoretical study using molecular mechanic and ab initio Hartree Fock methods, to model the adsorption of aniline on copper (100) showed results in good agreement with the experimental data. Aniline adsorbs parallel to the copper surface, showing no preference for a specific adsorption site. On the other hand, from ab initio Hartree Fock calculations, an adsorption energy between 2 kcal/mol and 5 kcal/mol is obtained, which is close to the experimental value, confirming that the adsorption of aniline on the metal substrate is rather weak. In view of these results, the orientation of the aniline molecule with respect to the copper surface is considered to be the dominant effect. 相似文献
9.
E. Ya. Gorenbein N. O. Labkovskaya I. L. Abarbarchuk 《Chemistry of Heterocyclic Compounds》1967,2(3):292-294
The reaction of quinoline with bromine in nitrobenzene solvent is investigated using the properties of isomolar series. These properties, viscosity, conductivity, density, depression of the freezing point, are determined using a constant molar concentration of C9H7N +Br2, 0.05 per mole of C6H5NO2. It is shown that the nitrobenzene solution of quinoline forms with bromine a complex with the composition C9H7N · Br2. The molecular conductivity of this complex in nitrobenzene solvent increases with dilution. 相似文献
10.
A comparison of the results of catalytic and electrocatalytic oxidation of aniline using VS-1 in the presence of H2O2 and TBHP indicates remarkable differences in conversion and selectivity. VS-1 catalyzes the oxidation of aniline selectively
to nitrobenzene (73%) in the presence oft-butyl hydroperoxide (TBHP), while azoxybenzene (95.2%) is formed selectively when H2O2 is used. Cyclic voltammetric studies show a three-step oxidation of aniline to nitrobenzene in H2O2 but in the presence of TBHP only one step is observed. Electrocatalytic oxidation of aniline to nitrobenzene occurs at a
potential 700 mV less than that corresponding to H2O2 as oxidant along with a selectivity of 91.8%. The enhancement of electrocatalytic rate is attributed to the stabilization
of electron deficient transition state. 相似文献
11.
N. John Jebarathinam M. Eswaramoorthy V. Krishnasamy 《Reaction Kinetics and Catalysis Letters》1996,58(2):291-298
The hydrogenation of nitrobenzene to aniline over reduced Cu(FexCr2–x)O4 series of catalysts (where x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) has been studied at 250°C in a fixed bed flow type reactor. All the catalysts were characterized by XRD, IR and DRS analysis and by measurements of electrical conductivity and surface area. The conversion of nitrobenzene to aniline is maximum over the catalysts with composition x=0.4. By comparing the results of reversible and irreversible adsorption of carbon monoxide with hydrogenation activity, it can be concluded that univalent copper at octahedral sites is more active for hydrogenation than metallic copper. The second cations [Cr(III) or Fe(III)] develop their catalytic activity by sharing anionic vacancies. 相似文献
12.
《印度化学会志》2021,98(11):100185
Sulfate-contaminated water is a major environmental problem that alters the taste of water, disturbs the digestive systems of animals and humans, and erodes both soil and metals. In this study, the layered double hydroxide LDH 4Mg2Al·NO3 and LDH 8Mg2Al·NO3 were prepared using a co-precipitation technique, and applied in the adsorption of SO42- from an aqueous solution. The reaction is well described by the Langmuir adsorption model. LDH 4Mg2Al·NO3 and LDH 8Mg2Al·NO3 afforded maximum SO42- adsorption values of 135.14 and 92.59 mg/g, respectively. The reaction is best explained by a pseudo-second-order mechanism, which suggests that chemisorption is the rate-determining step. The activation energies of LDH 4Mg2Al·NO3 and LDH 8Mg2Al·NO3 indicate that the adsorption of SO42- on synthetic LDHs predominantly follows an anion-exchange mechanism, wherein SO42- ions in the aqueous medium replaces intercalated NO3- ions in the synthetic LDHs. The thermodynamic parameters (ΔH̊, ΔS̊, and ΔG̊) were also calculated. The reaction was endothermic, and the synthetic LDHs afforded feasible and spontaneous adsorption of SO42-. 相似文献
13.
S. N. Yashkin 《Russian Chemical Bulletin》2013,62(5):1131-1142
The thermodynamic characteristics of adsorption (TCA) of polymantane molecules and their some derivatives on the basis face of graphite were calculated for the first time in terms of the atom-atomic approximation of the semiempirical molecular statistical theory of adsorption. The graphite surface exhibits high structural selectivity to isomeric polymantanes. A model for adsorption of cage molecules on the planar surface was proposed. The model is based on the idea that contributions of atoms of the adsorbate molecule to the total adsorption energy can be discriminated according to the distance of these atoms from the surface of a solid. Advantages and limitations of using the data on adsorption of molecules of isomeric alkanes, including rotamers, for the analysis of equilibrium TCA values of isomeric polymantanes on graphite are discussed. The possibility of separation of representatives of the polymantane hydrocarbon family by gas adsorption chromatography on columns with graphitized thermal carbon black was suggested on the basis of the calculated TCA values and logarithmic retention indices. 相似文献
14.
NO_x分子在[Ag]-MAPO-5(M=Si,Ti)分子筛中的吸附 总被引:1,自引:0,他引:1
采用密度泛函理论(DFT)研究了银离子交换的硅磷酸铝([Ag]-SAPO-5)和钛磷酸铝([Ag]-TAPO-5)分子筛结构及其对NOx分子的吸附,获得吸附复合物的平衡几何结构参数和吸附能.结果表明,NOx分子以η1-N模式吸附在[Ag]-SAPO-5和[Ag]-TAPO-5分子筛中的结构更稳定,其吸附作用强度的次序为NO2NON2O.[Ag]-SAPO-5和[Ag]-TAPO-5对NO和NO2分子的活化程度要比N2O大.相比[Ag]-AlMOR,[Ag]-SAPO-5和[Ag]-TAPO-5对NOx分子的活化程度较大.还对[Ag]-SAPO-5和[Ag]-TAPO-5分子筛的抗硫、抗水及抗氧化性能进行了研究和分析.另外,通过自然键轨道(NBO)计算,分析了NOx分子与平衡离子Ag+之间的作用机理. 相似文献
15.
Aluminum suspensions with different properties were prepared and characterized by UV–Vis spectra, BET, XRD and NH3-TPD. A layer of Al2O3 was coated onto the cordierite monolith by sol–gel method. Pd/Al2O3/cordierite monolith catalysts with the same Pd loading and particle size were prepared, and tested by nitrobenzene hydrogenation under solvent-free conditions. The adsorption of nitrobenzene on acid sites might be the primary effect under the reaction conditions, and a good linear relationship between hydrogenation rate and the acid content of the Al2O3 layer was observed. Furthermore, the stronger acid sites were responsible for the lower aniline selectivity.
相似文献16.
Václav Baran 《Journal of Molecular Structure》1975,29(2):335-348
Thirty-one complexes with general formula trans- [Co(NO2)(AA)2B] (where AA represents the acetylacetonate anion and B represents a range of variously substituted anilines or pyridines) have been synthesized and their infrared spectra determined. 15N-labelling of the complexes in which B is aniline and p-toluidine yields assignments of the cobalt-amine stretching frequencies and the internal vibrations of the amino group. Assignments of the cobalt-oxygen and cobalt-nitro stretching frequencies are based on comparison of the spectra with those of [Co(AA)3] and trans-Na[Co-(NO2)2(AA)2]. The assignments are supported by the nature of the dependence of the frequencies on the electronic effects of the substituents in the aniline and pyridine rings. 相似文献
17.
《International journal of mass spectrometry and ion processes》1986,68(1-2):57-70
Negative-ion/molecule reactions in systems containing methane as the major gas (∼ 4 torr), with NO2 and compounds A at mtorr pressures were studied in a pulsed electron, high pressure mass spectrometer. The compounds A were substituted nitrobenzenes and quinones. All these A compounds have positive electron affinities. Three types of reactions were observed and examined. (1) Electron transfer: A− + NO2 = A + NO2−. The exothermic electron transfer reactions proceeded with ADO collision rates for exothermicities from 30 to ∼ 10 kcal mol−1. Lower exothermicities led to low collision yields. (2) Adduct formation: NO2− + A = NO2−·A. The equilibria for adduct formation were determined. Stable adducts are formed when A has hydrogens with partial protic character. The stability of the adducts NO2−·A increased with increase in the electron affinity of A, when A was a substituted nitrobenzene. Substituents that increase the electron affinity of nitrobenzene are electron-withdrawing groups which also increase the protic character of the hydrogens involved in bonding in NO2−·A. (3) Some of the compounds A were converted to phenoxy negative ions on reaction with NO2−. For example, para-dinitrobenzene leads to formation of the para-nitrophenoxide negative ion. The oxy-negative-ion-forming reaction can be isomer specific. The utility of reaction types (1)–(3) is examined from the standpoint of negative ion chemical ionization where the reagent gas is NO2 in methane and the reagent ion is NO2−. 相似文献
18.
The voltammetric behaviour of aniline and some of its N-alkylated derivatives at a carbon-paste (Nujol/graphite) electrode is examined. The N-alkylated anilines, in contrast to aniline, are accumulated at the electrode by a combined adsorption/extraction process. The organic bases are determined in the rane 10?7?2×10?6 M after a 2-min preconcentration period by differential pulse voltammetry; N,N-dimethylaniline can be determined in the presence of excess of aniline (10?5 M) by using medium-exchange. The voltammetric method is used for evaluation of the distribution ratios of the organic bases in the Nujol/aqueous buffer system. The enhancement of the voltammetric signal of each base is correlated with the respective distribution ratio. 相似文献
19.
《液相色谱法及相关技术杂志》2012,35(16):3547-3556
Abstract Using the equation connecting the RM values with the appropriate data of the adsorption process from solutions the values of the parameters characterizing substance ? mobile phase interactions have been calculated for the systems: silica gel-benzene+acetone and silica gel-acetone+methanol.Quinoline, aniline, nitrobenzene, phenol and their derivatives were the chromatographed substances. An influence of the structure of the substance on the parameter values has been examined, special attention being paid to intramolecular effects, mainly those of hydrogen bonds. 相似文献
20.
Agnie Mylona Kosmas Aristeidis Ntivas Stavroula Liaska Demetrios K. Papayannis 《Chemical Papers》2012,66(12):1157-1165
The structural, energetic, and thermochemical properties of a number of halogenated nitromethanes, CH n X3?n NO2, and the isomeric nitrites, CH n X3?n ONO, are investigated, using theoretical ab initio and density functional theory (DFT) electronic structure methods. Analysis of the results and comparison with the maternal species, nitromethane, CH3NO2, and methyl nitrite, CH3ONO, reveal strong dependence of the molecular properties on the halogen induction effect. Opposite trends are obtained in the C??N and C??O bond dissociation energies (BDE) upon halogenation and higher stabilities are calculated for the trans-nitrite isomers, in contrast with the plain alkyl families where the nitroalkanes are the most stable species. Formation enthalpies, ??H f ? , at 298 K are calculated for all halogenated isomers. 相似文献