Reductive carbonylation of nitrobenzene over Pd/Fe/I2/Py and Pd/C/Fe/I2/Py catalytic systems

A simple catalytic system containing metallic palladium, iron and iodine has been shown to be very active in the carbonylation of nitrobenzene to carbamate. The influence of the components of the catalytic system studied on its selectivity and activity has been established. It has been found that the catalytic activity of palladium supported on carbon (using both lignite coal and bituminous coal) was not lower than the activity of metallic palladium. This revised version was published online in August 2006 with corrections to the Cover Date.     

Selective hydrogenation of nitrobenzene top-Aminophenol by the polymer-supported palladium-based mono- and bimetallic catalyst

In acidic reaction medium, polymer-supported monometallic palladium catalyst, PVP-PdCl₂ [(PVP=poly(N-vinyl-pyrrolidone)], is used to catalyze the hydrogenation of nitrobenzene top-aminophenol and aniline. The addition of a second transition metal compound or a very small amount of 2-mercaptopyrimidine gives rise to an increase in the selectivity forp-aminophenol.     

Synthesis and structure of the complex of 2-(2-pyridyl)-2-oxazoline with PdCl2

The reaction ofN-2-nitroxyethylpicolinamide with PdCl₂ afforded the new complexcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(u). The structure of this complex was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 561–563, March, 2000.     

Synthesis and crystal structure of 2-nitroxyethyl nicotinate and its complex with PdCl2

The reaction of nicotinoyl chloride with ethylene glycol mononitrate yielded the previously unknown 2-nitroxyethyl nicotinate. The resulting ester was used as a ligand in the reaction with PdCl₂ for preparing a new complex,trans-bis(2-nitroxyethyl nicotinate-N)dichloropalladium(ii). The structures of the ligand and the complex were established by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 527–530, March, 1998.     

Catalytic carbonylation of potassiumN,2-dichlorobenzenesulfonamidate to sulfonyl isocyanate

Application of acetonitrile as a solvent in the catalytic carbonylation of potassiumN,2-dichlorobenzenesulfonamidate allowed to reduce the catalyst/substrate ratio and the CO pressure as compared to those used with chlorinated hydrocarbons.     

Solvent effect on catalytic properties of the HCI-DMF-1,1,2,2-tetrachloroethane system

Ionization of 2- and 3-nitroanilines was studied in HCl-DMF-1,1,2,2-tetrachloro-ethane (TCE) solutions at 25 °C. The ionization capability of the medium and basicity constants pK _i of indicators change depending on the ratio of the components. The numerical values of pK _i are found to depend on the analytical composition of the DMF-TCE solvent. The solvent effect on pK _i is associated with a change in the solvation of the nonionized form of the indicators.Translanted fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1446–1449, June, 1996.     

Intensités des Transitions Électroniques de [PdCl4]2− Intensities of Electronic Transitions of [PdCl4]2−

The oscillator strengths of the symmetry-forbidden transitions of the ion [PdCl₄]^2– were calculated by a method based on the evaluation of the MO of the distorted ion. It is not very likely that the transition to¹ B _1g (a _1g (d _z ²)b _1g ) state, weak, mainlyz polarized, explains the band that appears as a shoulder observed towards 30 000 cm^–1 in the absorption spectrum. If this band is specific of the ion [PdCl₄]^2–, the assignment to the forbidden charge-transfer transition,¹ A _1g ¹ B _2g , is more plausible.

     

Reduction of Nitrobenzene to Aniline with Carbon Monoxide and Water in the Presence of the PdCl2/Fe/I2 System

A study of modified catalyst systems composed of palladium or its chloride and a co-catalyst such as metallic Fe-powder, iodine, and pyridine was used in the reduction of nitrobenzene to aniline with carbon monoxide and water at 180°C and 2.5-4 MPa pressure. The reaction is complete in 2 h with a nitrobenzene conversion of 98-100% and a 100% selectivity with respect to aniline.     

Synthesis and structures of complexes ofN-2-nitroxyethylpicolinamide and 2-(2-pyridyl)-2-oxazoline with PdCl2

The reaction ofN,N′-bis(2-nitroxyethyl)pyridine-2,6-dicarboxamide with PdCl₂ afforded previously unknowncis-(N-2-nitroxyethylpicolinamide-N,N′)dichloropalladium(II) andcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(II), which were isolated as a cocrystallizate of the molecular compounds. Its structure was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1604–1606, August, 1999.     

Synthesis and the crystal structures of N-(2-nitroxyethyl)isonicotinamide and its complexes with PdCl2 and PtCl2 as potential antitumor medicines

Previously unknown N-(2-nitroxyethyl)isonicotinamide was synthesized by the reaction of isonicotinoyl chloride with 2-nitroxyethylamine and was used as a ligand in the reactions with PdCl₂ and PtCl₂ to prepare new complexes, viz., trans-bis[(2-nitroxyethyl)isonicotinamide-N]dichloropalladium(ii) and cis-bis[(2-nitroxyethyl)isonicotinamide-N]dichloroplatinum(ii), respectively. The structures of the ligand and the resulting complexes were established by X-ray diffraction analysis.     

Complexation equilibrium in a substrate- MgCl2(CaCl2)-Pd/C catalytic system and the influence of its position on asymmetric induction in hydrogenation ofN-acetyl-dehydrophenylalanyl-S-proline

The role of Ca and Mg salts as promoters of asymmetric induction in hydrogenation ofN-acetyl-dehydrophenylalanyl-S-proline in a substrate— MX₂—Pd/C catalytic system was studied. The data of potentiometric titration,¹H NMR spectroscopy, and the value of diastereomeric excess (de) of the resultingN-acetyl-R-phenylalanyl-S-proline indicate the complexation of the substrate with calcium and magnesium chlorides in an alcoholic solution. Ionization and equilibrium constants of the complex were determined. Excess salt shifts the equilibrium toward the complex formation, which increasesde up to 70 %.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1964–1967, August, 1996.     

IR-spectral investigation of the structure of glasses in the Fe2O3-V2O5 system

The structure of glasses in the Fe₂O₃-V₂O₅ system in the 0–50 mol% Fe₂O₃ range is studied by IR-spectroscopy. It is found that the introduction of Fe₂O₃ favours the transformation of the VO₅-groups into VO₄ ones. This effect may be shown with the aid of IR-spectra, owing to the fact that these glasses are characterized by two high-frequency bands at 1020 and 930 cm^–1. The first is determined by the vibrations of the short V=O nonbridging bonds in the VO₅-groups, while the second is assigned to the vibrations of the V—O-bonds in deformed VO₄-tetrahedra.

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IR-spektroskopische Strukturuntersuchung von Gläsern des Systems Fe₂O₃-V₂O₅

Zusammenfassung Die Struktur von Gläsern des Systems Fe₂O₃-V₂O₅ in dem Bereich von 0–50 Molprozent Fe₂O₃ wurde mit Hilfe der IR-Spektroskopie untersucht. Zusatz von Fe₂O₃ begünstigt die Umwandlung der VO₅- in VO₄-Gruppen. Das kann in den IR-Spektren durch zwei Banden bei 1020 und 930 cm^–1 festgestellt werden. Die erste wird durch Schwingungen der kurzen V=O-Nichtbrücken-bindungen in den VO₅-Gruppen verursacht, die zweite wird auf Schwingungen der V—O-Bindungen in dem deformierten VO₄-Tetraeder zurückgeführt.

     

Fluoride effect on the palladium–phenanthroline catalyzed carbonylation of nitroarenes to carbamates

Fluorides promote the palladium–phenanthroline catalyzed carbonylation of nitroarenes to carbamates. The effect is more evident on the rate of the reaction at short reaction times, but a positive effect on selectivity is also observed under certain conditions. The effect is observed even under conditions under which chloride inhibits the reaction. Tetraethylammonium is a better countercation than sodium. Copyright © 2007 John Wiley & Sons, Ltd.     

Thermoanalytical and spectroscopic studies of the synthesis of suppokted palladium catalyst in A H2/PdCl2/SiO2 parent system

A 5 wt% Pd/SiO₂ catalyst was synthesized by heating PdCl₂-impregnated SiO₂ in H₂ at 300°C for 2 h. It was found that the metal particle dispersion is improved when the reduction step is preceded by calcination at 300°C for 2h. Thermogravimetry of the impregnated support in air, N₂ and H₂ atmospheres was used to monitor the interactions occurring during the various preparative steps (i.e. drying, calcination and reduction) of the catalyst. The solid prduct of each preparative step was characterized by X-ray diffractometry and UV/Vis diffuse reflectance spectroscopy. The results indicate that following the drying step (at 110°C in air) the palladium occurs in two detectable forms: PdCl₂ particles and Si?O?Pdⁿ⁺ surface species. The calcination appears to transform the PdCl₂ particles into the latter surface species. The H₂-reduction eventually converts the surface species into finely-dispersed Pd° metal particles (average size=8–14 nm). No other reduction products, such as Pd_ySi_x, were detected.     

Pt/SO42??ZrO2: The state of platinum and its relation with catalytic activity inn-hexane isomerization

Pt/SO₄ ²⁻−ZrO₂ calcined at 873 K shows the same catalytic activity forn-hexane isomerization as the calcined and reduced sample. A platinum reduction peak did not appear in the TPR profile and the presence of Pt⁰ was detected by XPS on the only calcined Pt/SO₄ ²⁻−ZrO₂. Nevertheless, this calcined material does not show hydrogen chemisorption and cyclohexane dehydrogenation activity.     

Investigation on The Thermal Properties of Fe2O(SO4)2. Part I

The data on the thermal decomposition of FeSO₄?H₂O upon various regimes of heating and gaseous environment prove the formation of intermediate products of the types Fe₂O(SO₄)₂ and FeOHSO₄, their stability and amount being determined mainly by temperature and oxygen-reduction potential.

This communication aims at presenting results on the synthesis and characterization of Fe₂O(SO₄)₂. The synthesis was carried out using a laboratory thermal equipment operating under isothermal conditions in the temperature range 713–813 K in a gaseous environment either poor in oxygen or containing 100% oxygen. The experimental conditions under which Fe₂O(SO₄)₂ is stable are established. The effect of three basic parameters on the synthesis of Fe₂O(SO₄)₂ is clarified: the oxygen partial pressure, the ratio P_H2O/P_O2 and the temperature and the mode of heating. Mössbauer spectroscopy and X-ray diffraction data for Fe₂O(SO₄)₂ are presented.

     

2-Azetidinones from 3-aminopropanoic acids and thePh 3P/CCl4(CBr4) orPh 3P/Br2(I2) condensation systems

The title complexes are used as intramolecular cyclization agents to yield under mild conditions and average to good yields 2-azetidinones from variously substituted 3-aminopropanoic acids. The reaction is found to proceed in all examined cases stereospecifically, with one exception. No marked difference with respect to yields and stereospecificity is noted among the four condensation systems.

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2-Azetidinone aus 3-Aminopropansäuren und Ph₃ P/CCl ₄(CBr ₄) oder Ph₃ P/Br ₂(I ₂) als Kondensationsmittel

Zusammenfassung Die im Titel angegebenen Systeme wurden als Cyclisationsreagentien eingesetzt, um aus substituierten 3-Aminopropansäuren 2-Azetidinone unter milden Bedingungen und mit durchschnittlichen bis guten Ausbeuten darzustellen. Mit einer Ausnahme läuft die Reaktion stereospezifisch. Bei den vier untersuchten Systemen wurde kein beträchtlicher Unterschied in bezug auf Ausbeute und Stereospezifität festgestellt.

     

The effect of pyridine bases and transition-metal oxides on the activity of PdCl2 in the carbonylation of aromatic mononitro compounds by carbon monoxide

Conclusions Palladium chloride which is a catalyst for the preparation of phenylisocyanates by the carbonylation of nitro compounds is promoted by pyridine and its homologs and also by transition-metal oxides, which provide for the conversion of nitro compounds into phenyl-, methylphenyl-, and chlorophenylisocyanates in 75–92% yield and 84–97% selectivity at 200°C and 50–100 atm CO.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 585–589, March, 1979.