On the conditions of existence of a silica-anchored carbonylphosphinecobalt complex as a heterogenized catalyst for propylene hydroformylation

Studies of the catalytic properties of silica-anchored carbonylphosphinebocalt complexes in propylene hydroformylation in relation to the CO partial pressure indicate that at low pressure (0.1 MPa) cobalt complexes are not removed from the support and hydroformylation takes place on anchored complexes.

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- CO. , (0,1 ) , .

     

Composition of the adduct formed in solutions containing an organomercury compound and cuprous chloride

ESR and NMR studies have been performed to detect adduct formation between an organomercury compound and Cu²⁺ ions in acetic acid solutions. The probable structure of the adduct is reported.

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- Cu²⁺. .

     

A stereoselective reducing agent derived from a nitrogen-containing polymer deposited on a carbon support

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2875–2876, December, 1990.     

Formation of platinum sites on layered double hydroxide type basic supports: II. Effect of the nature of the interlayer anion of the layered aluminum-magnesium hydroxides on platinum binding and Pt/MgAlO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> formation

The interaction of aqueous H₂PtCl₆ solutions with hydrotalcite-type aluminum-magnesium hydroxides differing in the nature of their interlayer anion is reported. In the case of CO₃²⁻ as the interlayer anion, the introduction of the platinum(IV) chloro complex does exerts no significant effect on the structural properties of the support, on its thermal decomposition dynamics, and on the textural characteristics of the resulting oxide phase. The binding of the platinum complexes to “activated hydrotalcite” with interlayer OH⁻ anions increases the interplanar spacing and enhances the thermal stability of the layered structure. This is accompanied by marked changes in textural characteristics of the material, leading to the formation of a nearly monodisperse mixed oxide phase. In the Pt/MgAlO _x samples obtained by reductive treatment, a considerable proportion of platinum is in the form of planar particles, and this corroborates the hypothesis that the metal complex at the sorption stage is mainly localized in the interlayer space of this support. Platinum binds to the support as chloro complexes via rapid anion exchange, and these bound platinum species are characterized by a higher reduction temperature.     

Liquid-phase hydrogenation of acetylene on the Pd/sibunit catalyst in the presence of carbon monoxide

The liquid-phase catalytic hydrogenation of acetylene into ethylene in the presence of CO over palladium supported on the graphite-like material Sibunit has been investigated. Carbon monoxide is an effective modifier of the selective hydrogenation process, exerting its effect by competing with acetylene and ethylene for chemisorption sites on the palladium surface. Under the optimum conditions (T = 90°C; N-methylpyrrolidone solvent; feed consisting of 2 vol % C₂H₂, 90 vol % H₂, and He balance), the introduction of 2 vol % CO ensures a high ethylene selectivity of 89.6 ± 1.5% at an acetylene conversion of 95.8 ± 1.3%, with the acetylene converted into hydrooligomers taken into account.     

Bimetallic palladium(II) and iron(III), titanium(IV), vanadium(V), cobalt(II), and copper(II) complexes with the [As2W19O67(H2O)]14− heteropolyanion

The formation of bimetallic Pd(II) and M = Fe(III), Ti(IV), V(V), Co(II), or Cu(II) complexes with the two-vacancy [As₂W₁₉O₆₇(H₂O)]^14? heteropolyanion (HPA) (below referred to as As₂W₁₉) has been studied by UV/Vis and IR spectroscopy and differential dissolution. In an aqueous solution at pH 6 and a Pd: M: As₂W₁₉ molar ratio of 1: 1: 1, heteropoly complexes (HPC) incorporating two different metals one being Pd(II) are formed. The resulting complexes were precipitated from solution as cesium salts. In the case of Pd(II) and M = Fe(III), Co(II), or Cu(II) ions, the precipitate contained bimetallic HPC [As₂W₁₉FePDO₆₇(H₂O)₂]^9? (65.9 wt %), [As₂W₁₉CoPdO₆₇(H₂O)₂]^10? (45.6 wt %), and [As₂W₁₉CuPdO₆₇(H₂O)₂]^10? (50.7 wt %) mixed with monometallic HPC [As₂W₁₉M₂O₆₇(H₂O)₂]^{(14 ? 2m)?} (As₂W₁₉M₂). In the case of Pd(II) and Ti(IV) or V(V), bimetallic HPC of a different composition were precipitated, namely, [As₂W₁₉Ti₂O₆₇(OH _x )₂ PdO]^{(10 ? 2x)?} (76.8 wt %) and [As₂W₁₉V₂O₆₇(OH _x )₂ PdO]^{(8 ? 2x)?} (15.0 wt %), where palladium ions are not incorporated in the HPC structure but are attached to the HPC surface, possibly, as hydroxide species. Using M = Pd(II), Ti(IV), V(V) ions and the HPA As₂W₁₉ ([M]: [As₂W₁₉] = 2 : 1, pH 6), new monometallic HPC, [As₂W₁₉Pd₂O₆₇(H₂O)₂]^10?, [As₂W₁₉Ti₂O₆₇(OH _x )₂]^{(10 ? 2x)?}, and [As₂W₁₉V₂O₆₇(OH _x )₂]^{(8 ? 2x)?} (x = 0, 1, or 2), were obtained.