The reduction of aromatic nitro compounds by oxiranes

Aromatic nitro compounds are reduced to the corresponding amines by epoxides at elevated temperatures (>170 °C).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1491–1494, August, 1994.The authors are grateful to Prof. Yu. N. Belokon' for his participation in the discussion of the results of the work.This work was financially supported by the Russian Foundation for Basic Research (code No. 93-03-18044).     

The synthesis of azo compounds from nitro compounds using lead and triethylammonium formate

Aromatic nitro compounds were reduced to the corresponding symmetrically substituted azo compounds using lead as catalyst and triethylammonium formate as hydrogen donor. Various azo compounds containing additional reducible substituents including halogens, nitrile, acid, phenol, ester, methoxy functions, etc, have been synthesized in a single step by the use of this reagent. The conversion is reasonably fast, clean, high yielding and occurs at room temperature in methanol.     

A theoretical study on the vibrational spectra and thermodynamic properties for the nitro derivatives of phenols

The nitro derivatives of phenols are optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level. Their IR spectra are obtained and assigned by vibrational analysis and are reliable compared with the experimental results. Based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics, the thermodynamic properties are evaluated, which are linearly related with the number of nitro and hydroxy groups as well as the temperature, obviously showing good group additivity.     

Carbonylation of nitro and azo compounds in the presence of iron carbonyl catalysts

The reactions of nitro and azo compounds with carbon monoxide were studied in the presence of iron carbonyl catalysts. It was shown that these catalytic systems differ substantially from Pd- and Rh-containing catalysts. In the case of the iron catalysts, the products of coupling of molecules are formed as intermediates and azo compounds are the final reaction products. The reactions involving the palladium and rhodium catalysts proceed without the intermediate formation of the coupling products and lead to isocyanates or carbamates. When combined using PdCl₂ and Fe(CO)₅/Al₂O₃, the catalysts inhibit each other, especially in the presence of pyridine.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2460–2463, October, 1996.     

Synthesis of a cobalt-based photoluminescent coordination complex to study quenching mechanisms of nitro compounds

Abstract

A cobalt metal coordination complex was synthesized using the bipyridyl spacer ligand along with a dicarboxylate as secondary ligand. The coordination complex was characterized using FTIR, ¹H NMR, elemental analysis, thermogravimetric analysis, and powder XRD. The structure shown from single-crystal XRD revealed that each Co(II) cation in the cluster can be described as trigonal bipyramidal. Luminescence properties of the complex were investigated using different solvents. The photoluminescence (PL) spectra depicted change in band gap for THF and DCM. The complex was further investigated for ligand-based photoluminescence properties and thus used for sensing of nitro compounds. The static and dynamic quenching mechanism of nitro compounds was identified through the Stern–Volmer model.     

Catalytic hydrogenation of aromatic nitro compounds by non-noble metal complexes of chitosan

Silica-supported mono-metal (such as Ni, Cu) complexes and mixed metal (such as Cu/Zn, Cu/Cr) complexes of chitosan have been prepared. It is found that these non-noble metal complexes could be used as efficient catalysts for the hydrogenation of aromatic nitro compounds. The effects of type of metal, reaction temperature and pressure, solvent, nitrogen/metal molar ratio in the complex catalysts on the yields from nitrobenzene to aniline have been examined. It was also found that catalysts are active for the catalytic hydrogenation of other aromatic nitro compounds such as 2-nitroanisole, 2-nitroaniline, 2-nitrotoluene and 1-chloro-4-nitrobenzene.     

The thermodynamic properties of alkali metal compounds at high temperatures

A research program has been in progress to obtain reliable thermodynamic data on various binary and ternary alkali metal compounds in the temperature range of 300 to 1500 K. To date, heat capacity measurements have been made on cesium and rubidium chromates, dichromates, zirconates, molybdates, dimolybdates, and halides in the temperature range of 300 to 800K. In addition, measurements are planned or are currently in progress on cesium and rubidium chalcogenides, aluminates, uranates, silicates, and several other lithium, sodium, and potassium compounds. The status of the research program is discussed.     

A novel general method for the synthesis of nitrones by reaction of nitroso compounds with anions of aliphatic nitro compounds

Anions of aliphatic nitro compounds R¹R²C=NO₂ ^– react with nitroso compounds RNO to give nitrones R¹R₂C=N(O)R. Salts of nitro compounds with metals and Et₃N, as well as trimethylsilyl nitronates in the presence of F^–, can serve as the sources of the anions. The structure of the nitrones was established by NMR spectroscopy. 1,3-Dipolar cycloaddition of a series of the nitrones obtained to olefins was investigated.For a brief communication see Ref. 1Translated from IzvestiyaAkademii Nauk. Seriya Khimicheskaya, No. 4, pp. 901–907, April, 1996.     

Theoretical assessment of structural,mechanical, and thermodynamic properties of Pd2Al

The physical properties, namely structural, mechanical, and thermodynamic properties, of Pd₂Al intermetallic compound were explored through first-principles calculations within the framework of density functional theory. The calculated lattice constants were consistent with the available experimental data. The calculated elastic constants revealed that Pd₂Al was mechanically stable. By the predicted elastic constants, several related properties, namely Cauchy pressures, shear anisotropy factors, directional Young's modulus, bulk, shear and Young's moduli, the ratio of K/G, Vickers hardness, sound velocity, and minimum thermal conductivity for Pd₂Al were evaluated. According to the calculated results, it was found that Pd₂Al possesses a highly anisotropic feature and behaves in a ductile manner with low stiffness. Finally, temperature-dependence of thermodynamic properties, namely Debye temperature and heat capacity, were also evaluated through the quasi-harmonic Debye model.     

Interaction of the trimethylsilyl cation with molecules of aliphatic nitro compounds in the gas phase

Interaction of mononitroalkanes with the trimethylsilyl cation in the gas phase under chemical ionization (CI) conditions results in the formation of [M+SiMe₃]⁺ ions, which are more stable than the corresponding protonated molecular ions. In the case of 2-nitro-2-methylpropane and 2-nitropentane, fragmentation of the [M+SiMe₃]⁺ ions occurs with the formation of C₄H₉ ⁺ and C₅H₁₁ ⁺ carbocations, respectively. In the case of 1,1-dinitroethane and 1-halo-1,1-dinitroethane, fragmentation of the [M+SiMe₃]⁺ ions occurs with splitting off of a NO₂ ^. radical or an XNO₂ molecule (X=H, F, or Cl). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1232–1234, June, 1997.     

Synthesis of 4,5-dihydroisoxazoles by condensation of primary nitro compounds with alkenes by using a copper/base catalytic system

A new procedure for the synthesis of 4.5-dihydroisoxazoles by condensation of primary nitro compounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activated nitro compounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles in the presence of the base alone, undergo the reaction on addition of a copper(II) catalyst. The observed occurrence of induction periods in most reactions is ascribed to an equilibrium preceding the rate-determining step, and gives a hint as to the proposed reaction mechanism. The results indicate that this method might be of practical and general utility for synthetic practice.     

A simplified prediction of entropy of melting for energetic compounds

A new widely applicable model for the prediction of the entropy of melting of organic compounds is presented. The use of three simple geometry based parameters: rotational symmetry, flexibility, and eccentricity enables the simple and accurate prediction of this important property. This paper demonstrates the use of the model for energetic compounds.     

A proposed equation of correlation for the study of thermodynamic properties (density,viscosity, surface tension and refractive index) of liquid binary mixtures

The literature on the physicochemical properties of liquid binary mixtures shows that most such systems exhibit nonlinear behavior. As a result, rigorous data and equations capable of affording a reliable estimate of the behavior of such mixtures are needed.     

QSPR approach to the calculation of rate constants of homolysis of nitro compounds in different states of aggregation

A method for the theoretical estimation and prediction of rate constants of homolysis of nitro compounds of different chemical classes in the gas phase is proposed on the basis of the QSPR approach.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1653–1656, September, 1995.The authors express gratitude to B. A. Lur'e (D. I. Mendelev Moscow Academy of Chemical Technology) for fruitful advice during discussion of the results.     

活性炭负载氢氧化氧铋催化水合肼还原芳香族硝基化合物

采用浸渍法制备了BiO(OH)/C催化剂。催化剂的XRD谱表明,当催化剂中BiO(OH)的质量分数小于10%时,BiO(OH)在活性炭中高度分散。反应温度为75 ℃时,催化剂重复使用7次仍保持较高活性。在5 mL乙醇中以0.05 g 10%（质量分数）BiO(OH)/C,1 mmol芳香族硝基化合物和2 mmol水合肼于75 ℃反应一定的时间,所得芳胺的收率为88%～99%。