Showing papers on "Palladium published in 1971"
1,120 citations
TL;DR: In this paper, a basis for distinguishing between chemisorption and phase formation is presented, which can be used for accurate measurement of real surface area of rhodium and palladium electrodes.
290 citations
260 citations
251 citations
Patent•
04 Mar 1971
TL;DR: In this paper, a high melting, high MOLECULAR WEIGHT INTERPOLYMERS of CARBON MONOXIDE with at least one UNSATURATED COMPOUND SUCH as the AlIPHATIC MONOOLEFINS, I.E., ETHYLENE, are PREPARED by reacting with SAID UnsatUROUNDED COMPOUNDS in the PRESENCE of an ARYL PHOSPHINE COMPLEX OF A PALLADIUM HALIDE and CERTAIN INERT SOLVENTS.
Abstract: HIGH MELTING, HIGH MOLECULAR WEIGHT INTERPOLYMERS OF CARBON MONOXIDE WITH AT LEAST ONE UNSATURATED COMPOUND SUCH AS THE ALIPHATIC MONOOLEFINS, I.E., ETHYLENE, ARE PREPARED BY REACTING CARBON MONOXIDE WITH SAID UNSATURATED COMPOUNDS IN THE PRESENCE OF AN ARYL PHOSPHINE COMPLEX OF A PALLADIUM HALIDE AND CERTAIN INERT SOLVENTS.
203 citations
TL;DR: Using inelastic neutron scattering, the frequency and wave vector dispersion relations for the lattice vibrations in a single crystal of palladium have been determined at 120, 296, 673, and 853 °K.
Abstract: Using inelastic neutron scattering, the frequency – wave vector dispersion relations for the lattice vibrations in a single crystal of palladium have been determined at 120, 296, 673, and 853 °K. A...
178 citations
TL;DR: In this paper, the relationship between chemical structure of reactants and the kinetic parameters of the catalytic reaction (activation entropy and activation energy) was elucidated by these measurements, and the fractional surface coverage of the catalyst with chemisorbed oxygen and hydrogen abstraction from the organic compound appeared to control the rates of catalytic oxidation.
143 citations
TL;DR: Extended Huckel and CNDO calculations have been made for Ag and Pd aggregates as mentioned in this paper, and the I.P. and E.A. in both types of geometry converge to a common value at 20 atoms in Ag and at 4 atoms in Pd.
Abstract: Extended Huckel and CNDO calculations have been made for Ag and Pd aggregates. Bond energy, ionization potential (I.P.), and electron affinity (E.A.) are reported for these particles up to 30 atoms in size. Linear chains are the most stable geometric form of small Ag aggregates, but a transition above 30 atoms is expected at which fcc is more stable. The three‐dimensional symmetric geometry is the most stable form of small Pd aggregates. The I.P. and E.A. in both types of geometry converge to a common value at 20 atoms in Ag and at 4 atoms in Pd. These converged values depend upon aggregate geometry, but do approach the work function of bulk metal. Palladium particles are found to have ≈ 0.35 d‐band hole per atom, which is close to values reported for bulk metal.
139 citations
TL;DR: In this paper, Azobenzene is halogenated by chlorine and bromine selectively ortho to theazo group when its solutions are treated with the respective halogen in the presence of a palladium(II) catalyst.
111 citations
107 citations
TL;DR: In this paper, the possibility of π-interaction between the two alkynyl groups through central metal was discussed in relation to the influence of R. This band was assigned empirically to the transition between the molecular orbitals involved in metal-alkynyl bonds.
Abstract: Electronic spectra of trans-[L2M(C≡CR)2], (L=tertiary phosphine or tertiary stibine, and M=Ni, Pd or Pt) have been studied in solution from 220 mμ to 360 mμ. Nickel and platinum complexes showed three intense absorption bands. The lowest energy band was particularly sensitive to substituents of alkynyl groups. This band was assigned empirically to the transition between the molecular orbitals involved in metal-alkynyl bonds. The possibility of π-interaction between the two alkynyl groups through central metal was discussed in relation to the influence of R.
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TL;DR: In this article, the catalytic hydrogenolysis of n-heptane was investigated on a series of noble metal catalysts in the form of powders, including palladium, rhodium, ruthenium, platinum, and iridium.
TL;DR: In this paper, the synthesis of vinyl acetate by vapor phase oxidation of ethylene-acetic acid mixtures has been studied using catalysts prepared by palladium deposition on silica or alumina supports.
TL;DR: In this article, a palladium lattice with hydrogen atoms in octahedral positions is described in terms of a lattice formed by soaking powdered palladium in gaseous hydrogen.
Abstract: Neutron diffraction measurements have been made on palladium hydride formed by soaking powdered palladium in gaseous hydrogen. The results obtained are best described in terms of a palladium lattice with hydrogen atoms in octahedral positions.
Palladiumhydrid, durch Absorption von gasformigem Wasserstoff in Palladiumpulver hergestellt, wird mit Neutronenstreuung untersucht. Die experimentellen Ergebnisse werden mittels eines Palladiumgitters mit Wasserstoffatomen in oktaedrischen Lagen am besten beschrieben.
TL;DR: In this paper, the synthesis and properties of the stable zerovalent palladium carbonyl complexes are described, and the trinuclear cluster [Pd 3 (CO) 3 (PPh 3 ) 3 ] has been obtained by the reaction between equimolar quantities of palladium(II) acetylacetonate and triphenylphosphine.
TL;DR: In this paper, the adsorption and absorption of hydrogen on palladium wires cleaned by treatment in oxygen to remove surface impurities have been studied using flash filament desorption.
Patent•
04 Mar 1971TL;DR: HIGH MELTING, CRYSTALLINE INTERPOLYMERS of CARBON MONOXIDE with one or more UNSATURATED COMPOUNDS SUCH AS ALIPHATIC MONOOLEFINS PARTICULARly ETHYLENE, are PREPARED by reacting CARBon MONIXIDE with SAID UNSatURATED COUNTS in the PRESENCE OF SELECTED INERT SOLVENTS and a CATALYTIC AMOUNT of TETRAKIS(TRIARYL PHOSPHINE)
Abstract: HIGH MELTING, CRYSTALLINE INTERPOLYMERS OF CARBON MONOXIDE WITH ONE OR MORE UNSATURATED COMPOUNDS SUCH AS ALIPHATIC MONOOLEFINS PARTICULARLY ETHYLENE, ARE PREPARED BY REACTING CARBON MONIXIDE WITH SAID UNSATURATED COMPOUNDS IN THE PRESENCE OF SELECTED INERT SOLVENTS AND A CATALYTIC AMOUNT OF TETRAKIS(TRIARYL PHOSPHINE) PALLADIUM, PARTICULARLY TETRAKIS(TRIPHENYL PHOSPHINE) PALLADIUM.
Patent•
29 Dec 1971TL;DR: In this article, the authors show that at least 95% of the mined Palladium and gold are transformed into WATER INSOLUBLE NOBLE METAL COMPOUNDS.
Abstract: HIGHLY ACITIVE CATALYSTS FOR THE PREPARATION OF CATALYSTS SUITABLE FOR VINYL ESTER, E.G., VINYL ACETATE, PRODUCTION ARE PREPARED BY TREATING A CATALYST SUPPORT, SIMULTANIOUSLY OR IN EITHER SEQUENCE, WITH OR WITHOUT INTERMEDIATE DRYING, WITH: (A) A SOLUTON OF NOBLE METALS CONTAINING AT LEAST SALTS OF PALLADIUM AND GOLD, AND (B) A SOLUTION CONTAINING COMPOUNDS, E.G., GASES SUCH AS SODIUM HYDROXIDE, WHICH ARE ABLE TO REACT WITH THE NOBLE METAL SALTS OF THE SOLUTION (A) TO FORM WATER INSOLUBLE NOBLE METAL COMPOUNDS; IMPREGNATING THE CATALYST SUPPORT WITH SUCH QUANTITIES OF SOLUTIONS (A) AND (B) CORRESPONDING TO FROM 10 TO 110% OF THE ABSORPTIVE CAPACITY OF THE CATALYST SUPPORT FOR THESE SOLUTIONS; SUBJECTING THE IMPREGNATED CATALYST SUPPORT TO A TIME TEMPERATURE TREATMENT SUCH THAT AT LEAST 95% OF THE IMPREGNATED PALLADIUM AND GOLD ARE TRANSFORMED INTO WATER INSOLUBLE NOBLE METAL COMPOUNDS; REDUCING THE METAL COMPOUNDS TO THE NOBLE METAL WITH A REDUCING AGENT, E.G., ETHYLENE OR HYDRAZINE; REMOVING THE WATER-SOLUBLE COMPOUNDS WHICH ARE CONTAINED IN THE CATALYST BY WASHING BEFORE OR AFTER THE REDUCTION STEP; AND OPTIONALLY TREATING THE RESULTING CATALYST WITH AN ALKALI METAL CARBOXYLATE, E.G., ACETATE, BEFORE OR AFTER THE TREATMENT WITH THE REDUCING AGENT.
TL;DR: In this paper, the equilibrium constant for transfer of hydrogen atoms from the surface to the bulk of a palladium membrane was measured and the apparent standard free energy for the process increases linearly with fractional coverage up to θ = 0·15 and remains constant at higher values of θ, indicating the existence of two types of surface sites.
TL;DR: Gorsky effect measurements applied to H and D in Pd show that D diffuses faster than H in the temperature range from about -60 °C to 200 °C as discussed by the authors.
Abstract: Gorsky-effect measurements applied to H and D in Pd show that D diffuses faster than H in the temperature range from about -60 °C to 200 °C. The diagonal components of the dipolemoment tensor has been estimated as 3.5 eV.
TL;DR: In this article, it is shown that the catalysts undergo continuous deactivation as a result of the absorption of a small but significant fraction of the hydrogen which is formed as a product of the reaction.
TL;DR: Preparations and various interconversion reactions are described in this paper for the complexes: [M2X2(PPh2O)2(pPh2OH2], [MX(Pph2O)(PPh 2OH)2], and [M(PPH2O), where M = palladium or...
Abstract: Preparations and various interconversion reactions are described for the complexes: [M2X2(PPh2O)2(PPh2OH2], [MX(PPh2O)(PPh2OH)2], [MX(PPh2O)(PPh2OH)(PEt3)], and [M(PPh2O)2]n where M = palladium or ...
TL;DR: In this paper, the reaction of ethanol with carbon monoxide at atmospheric pressure and mild temperatures in the presence of palladium chloride and lithium chloride produces ethyl chlorocarbonate, ethyl acetate, palladium metal, and an unidentified compound.
TL;DR: In this article, the reaction of n -pentane in the presence of hydrogen was studied using supported Group VIII transition metals as catalysts, and the specific activity for hydrogenolysis referred to unit surface area of the metal was examined and the following sequence was obtained: Ru > Rh > Pt > Ni > Co > Ir > Pd ~ Fe.
Patent•
21 May 1971
TL;DR: In this article, an improved version of the catalytic, VAPOR PHASE production of VINYL ACETATE from ETHYLENE, ACETIC ACID and MOLECULAR OXYGEN was shown.
Abstract: AN IMPROVED CATALYST FOR THE CATALYTIC, VAPOR PHASE PRODUCTION OF VINYL ACETATE FROM ETHYLENE, ACETIC ACID AND MOLECULAR OXYGEN SI SHOWN. A CATALYST FOR THE SYNTHESIS REACTION COMPRISING METALIC PALLADIUM AND AN ALKALI META ACETATE OR FORMATE SUPPORTED ON A CARRIER IS ACTIVATED BY INCLUDING METALLIC GOLD THEREIN. A PREFERRED CATALYST COMPOSITION WHICH SHOWS SUBSTANTIALLY IMPROVED OPERATING CHARACTERISTICS INCLUDES METALLIC PALLADIUM, AN ALKALI METAL ACETATE AND METALLIC GOLD. ANOTHER PREFERRED CATALYST COMPOSITION INCLUDES A LOW MELTING MIXTURE OF AT LEAST TWO ALKALI METAL ACETATES.