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Showing papers on "Catalysis published in 1976"


Book
01 Jan 1976

1,203 citations


Book
01 Jan 1976

529 citations


Journal ArticleDOI
TL;DR: In the presence of cyanide ions as catalyst, aromatic and heterocyclic aldehydes can be smoothly added to α,β-unsaturated ketones, esters and nitriles in aprotic solvents to form γ-diketones, 4-oxo carboxylic esters, and 4-oxy-nitriles as mentioned in this paper.
Abstract: In the presence of cyanide ions as catalyst, aromatic and heterocyclic aldehydes can be smoothly added to α,β-unsaturated ketones, esters, and nitriles in aprotic solvents to form γ-diketones, 4-oxo carboxylic esters, and 4-oxo nitriles. Thiazolium salts in the presence of bases are also suitable catalysts; they permit not only addition of aromatic and heterocyclic aldehydes but also the addition of aliphatic aldehydes.

494 citations


Journal ArticleDOI
TL;DR: In this paper, two steps of the overall mechanism have been identified, namely, dissociation of CO and hydrogenation of deposited carbon by adsorbed hydrogen, and they have been studied on Ni and Ni-Cu alloy films at low pressures, at temperatures of 250-350 °C.

465 citations



Book ChapterDOI
TL;DR: All the experimental results point to the conclusion that, with electrocatalysts, as with natural oxygen carriers, the interaction essential for catalysis takes place between the oxygen and the central metal ion.
Abstract: Electrocatalysis in fuel cells requires as well substances capable of catalyzing the anodic oxidation of fuels as catalysts for the cathodic reduction of oxygen. Several dyestuffs that catalyze oxygen reduction are known, but up to now only one has been described as active in anodic reactions. All these dyestuffs are N4-chelates. Comparative studies have shown that chelates with other types of coordination, in particular N202-, 04-, N2S2- and S4-chelates, are able to catalyze the reduction of oxygen, though they are considerably less active than the N4-compounds. With a given type of coordination, the nature of the central atom has a decisive influence on the catalytic activity of the dyestuff, whereas substitution on the organic skeleton has only a slight effect. Thermal pretreatment of the N4-chelates can considerably increase their stability in electrolytes containing sulfuric acid. All the experimental results point to the conclusion that, with electrocatalysts, as with natural oxygen carriers, the interaction essential for catalysis takes place between the oxygen and the central metal ion. Various assumptions may be made as to the nature of the rate-determining step. The cathodic reduction of oxygen can be regarded as redox catalysis, or it can be considered from the standpoint of molecular orbital theory. The models hitherto suggested for the mechanism of oxygen reduction are tested against the experimental results and a modified model based on MO theory is put forward.

384 citations


Journal ArticleDOI
TL;DR: In this paper, a study of the chemistry involved in preparation, pretreatment, and reduction of Ni Al 2 O 3 catalysts was carried out using hydrogen chemisorption, thermal gravimetric analysis, and chromatographic analysis.

347 citations


Patent
08 Oct 1976
TL;DR: In this paper, the synthesis gas is contacted with an intimate mixture of a carbon monoxide hydrogen reduction catalyst, comprising a methanol synthesis catalyst in combination with a selective class of acidic crystalline aluminosilicate having a silica/alumina ratio greater than 12, a pore dimension greater than about 5 Angstroms.
Abstract: Synthesis gas is contacted with an intimate mixture of a carbon monoxide hydrogen reduction catalyst, comprising a methanol synthesis catalyst in combination with a selective class of acidic crystalline aluminosilicate having a silica/alumina ratio greater than 12, a pore dimension greater than about 5 Angstroms to produce hydrocarbon mixtures useful in the manufacture of heating fuels, gasoline, aromatic hydrocarbons, and chemicals intermediates

340 citations



Journal ArticleDOI
TL;DR: In this article, a combination of group VIII transition-metal complexes and bases was used to synthesize formic acid from carbon dioxide and hydrogen in the presence of water far less than the equivalent amount of the catalyst.
Abstract: Formic acid was catalytically synthesized from carbon dioxide and hydrogen by a combination of group VIII transition-metal complexes and bases in the presence of water far less than the equivalent amount of the catalyst.

267 citations


Book ChapterDOI
TL;DR: In this article, the subject of metal-catalyzed oxidations of organic compounds in the liquid phase, largely within a mechanistic framework, has been discussed and a better understanding of the catalytic action of metal complexes is essential from the view of increasing selectivity and efficiency.
Abstract: Publisher Summary The liquid phase oxidation of hydrocarbons by molecular oxygen forms the basis for a wide variety of petrochemical processes including the manufacture of phenol and acetone from cumene, adipic acid from cyclohexane, terephthalic acid from p -xylene, acetaldehyde and vinyl acetate from ethylene, and propylene oxide from propylene. The majority of these processes employ catalysis by transition metal complexes to attain maximum selectivity and efficiency. This chapter describes the subject of metal-catalyzed oxidations of organic compounds in the liquid phase, largely within a mechanistic framework. A better understanding of the catalytic action of metal complexes is essential from the point of view of increasing selectivity and efficiency. Metal-catalyzed oxidations may be conveniently divided into two types—homolytic and heterolytic. The homolytic catalysis involves soluble transition metal salts (homogeneous), such as the acetates or naphthenates of Co, Mn, and Cu, or the metal oxides (heterogeneous). Heterolytic catalysis involves reactions of organic substrates coordinated to transition metals.

Journal ArticleDOI
TL;DR: In this article, the dehydrogenation and hydrogenolysis were studied on platinum single crystal surfaces of varying atomic surface structure at low pressures (10−6 Torr) in the temperature range of 300 −723 K. The active catalyst surface was covered with a carbonaceous overlayer.

Journal ArticleDOI
TL;DR: Canich et al. as discussed by the authors showed that 526/348.4 5,026,798 6/1991 Canich, Ewen et al., and Tominari et al.
Abstract: 3,491,073 i/1970 Marinak ............................. 260/88.2 3,645,992 2/1972 Elston . 4,205,021 5/1980 Morita et al........................ 525/240 4,405,774. 9/1983 Miwa et al. . ... 526/348.2 4,510,303 4/985 Oda et al. ............................ 526/283 4,530,94 7/1985 Ewen et al. ......................... 502/13 4,668,752 5/1987 Tominari et al. ... 526/348.2 4,935,474 6/1990 Ewen et al. ......................... 526/114 4,937,299 6/1990 Ewen et al. ......................... 526/119 4,987,212 1/1991 Morterol et al. 526/348.4 5,026,798 6/1991 Canich ................ ... 526/12 5,055,438 10/991 Canich ................ ... 502/17 5,084,540 l/1992 Albizzati et al. ................. 526/348.6



Journal ArticleDOI
TL;DR: In this article, the authors explore the relationship between the catalytic activity and the defect chemistry of perovskitelike cobaltites, manganites, chromites, and ruthenates.
Abstract: The high expectations present-day society has for catalysis in solving the energy crisis, in coping with environmental pollution, and in providing fertilizers and food have made research in catalysis the focus of interest in many adjacent fields. As an example, the science of solid surfaces in vacuum is explored for its relevance to and experimentally, a link has indeed been e ~ t a b l i s h e d . ~ Perhaps of even more importance, new interest has been stimulated in the links between solid-state physics and chemistry and the characteristics of solid catalysts. In earlier years, this connection had of course been explored on the heels of the spectacular development of semiconductor physics,\" but the fact that the best-studied semiconductors were poor catalysts has impeded progress in the establishment of detailed relationships between collective electrical properties and catalysis. Even so, a general relation between catalytic activity and the width of the band gap of a semiconductor has been recognized,' notwithstanding the frequent exceptions. Not only collective electrical properties, but also collective magnetic properties and ferroelectric properties have in those early years been explored in relation to catalytic characteristics. The relation was indeed established in work on the ferromagnetic man anese perovskite La~,6sSro,3sMn039 and on the ferroelectric perovskite KNbO,,' but the effects were small, which is perhaps not surprising. I ' The study of collective electron effects in metallic catalysts, I2-I4 which was initially partly based on the now ~ u p e r s e d e d ~ ~ . ' ~ rigid-band model of alloy systems such as Cu-Ni and Ag-Pd, has recently taken an interesting turn in the proposed relation between spin fluctuations connected with ma netic interactions and the momentum transfer t o a desorbing or reacting adatom. Surveying the relations between solid-state chemistry and catalysis, it becomes evident that in particular the number and type of localized defects in the solid have been successfully correlated with catalytic activity, e.g., for dislocations and steps on metal surface^,^^.^^ for surface states split off from the conduction band in semiconductors,21 and for anion vacancies or cation vacancies in insulators22 and s e m i c ~ n d u c t o r s . ~ ~ ~ ~ ~ In the present series of lectures on solid-state chemistry and catalysis, further examples of the role of anion and cation vacancies are given by Sleight, Schuit, and Longo. The topic of the present paper, defect chemistry of perovskite-type catalysts for oxidation-reduction processes, has received some stimulus from the suggestions that LaCo03, LaMn03, and their derivatives might be interesting catalysts for application in fuel cell electrodes2' and in the conversion of N O and C O from automotive e x h a ~ s t . ~ ~ ~ ~ In the following, the reduction of N O with CO and H2, and the oxidation of CO with O2 will be used as test reactions. We will explore the relationships between the catalytic activity and the defect chemistry of perovskitelike cobaltites, manganites, chromites, and ruthenates. The crystal structure of perovskite (CaTi03) is shown in FIGURE 1. The 97.1,

Journal ArticleDOI
TL;DR: In this paper, a large number of platinum-based binary catalysts have been prepared by deposition of submonolayer amounts of the second components onto the surface of platinum catalysts via an immersion method.

Journal ArticleDOI
TL;DR: In this article, the infrared spectroscopic study was made of NO and CO and their mixture adsorbed on rhodium metals supported on γ-alumina.

Journal ArticleDOI
TL;DR: In this article, the authors studied the stoichiometric reactions of organometallic compounds and showed that they represent the analogs of intermediate species formed in the process of catalytic reactions.
Abstract: Rapid development of organometallic chemistry of transition elements in recent years has greatly influenced homogeneous catalysis. Many organometallic compounds of transition metals have been directly used as effective catalysts; e.g., π-ally1 complexes of transition elements for diene reactions [1–3], carbonyl complexes for hydroformilation [4], and cyclopentadienyl and arene complexes for hydrogenation [5]. The study of stoichiometric reactions of organometallic compounds was also of great importance for homogeneous catalysis as individual organometallic compounds of various classes represent the analogs of intermediate species formed in the process of catalytic reactions (e.g., π-complexes and σ-organometallic compounds [6–8] in various reactions where the original catalyst is not an organometallic compound).

Patent
15 Jul 1976
TL;DR: In this article, an efficient polyolefin manufacturing process capable of preventing the formation of a sheet-like polymer and allowing an olefin polymerization reaction to be started stably is provided.
Abstract: According to the present invention, in a vapor phase polymerization of olefins, there is provided an efficient polyolefin manufacturing process capable of preventing the formation of a sheet-like polymer and allowing an olefin polymerization reaction to be started stably. More particularly, there is provided a process of preparing a polyolefin by homopolymerizing or copolymerizing an olefin or olefins substantially in a vapor phase condition and in the presence of a catalyst comprising a solid catalyst component and an organometallic compound, the solid catalyst component containing magnesium, one or more elements selected from titanium and vanadium and also containing halogen, wherein, in feeding the catalyst into a reactor the interior of which is held substantially in a vapor phase condition, in the presence of a polyolefin serving as a medium for dispersing the catalyst and in a state not substantially inducing a polymerization reaction in the presence of only the said polyolefin serving as the said medium, to start homopolymerization or copolymerization of the olefin(s), a solid catalyst component satisfying the above condition and having an average particle diameter substantially larger than that of the solid catalyst component to be used in a principal stage of the polymerization reaction is used at least until an olefin homopolymer or copolymer is formed in an amount equal to the amount of the polyolefin used as the catalyst dispersing medium.

Journal ArticleDOI
M.A. Vannice1
TL;DR: In this article, the catalytic behavior of unsupported nickel and nickel dispersed on a variety of supports has been studied in the CO H 2 synthesis reaction, and the catalysts were characterized by chemisorption and X-ray diffraction measurements.

Journal ArticleDOI
TL;DR: In this article, the electrocatalytic activity of 31 metals for the hydrogen and oxygen evolution reaction in 0.1M H/sub 2/SO/sub 4/ at 80/sup 0/C was determined.
Abstract: Cyclic voltammetry was used to determine the electrocatalytic activities of 31 metals for the hydrogen and oxygen evolution reaction in 0.1M H/sub 2/SO/sub 4/ at 80/sup 0/C. For the hydrogen evolution reaction, properties of the metals such as electronic structures, work functions, and metal-hydrogen bond strengths tend to correlate with the observed electrocatalytic activities. The best electrocatalysts for the hydrogen evolution reaction in the order of decreasing catalytic activity are Pd greater than Pt approximately equal to Rh greater than Ir greater than Re greater than Os approximately equal to Ru greater than Ni. For the oxygen evolution reaction, the order of catalytic activity is Ir approximately equal to Ru greater than Pd greater than Rh greater than Pt greater than Au greater than Nb. Most other metals undergo anodic corrosion and cannot be used for the evolution of oxygen in acid solutions. The potentials at which corrosion is observed are presented for these metals.

Journal ArticleDOI
TL;DR: In this paper, the authors studied the adsorption of carbon monoxide, ethene, and deuterium on platinum, Pt3Sn, PtSn, and PtSn2 and found significant differences between the surface and the bulk composition of the alloys.

Journal ArticleDOI
TL;DR: In this article, it was shown that the catalysis of carbon monoxide oxidation on a thoria surface treated in oxygen and in vacuo is accompanied by a specific luminescence.

Journal ArticleDOI
TL;DR: In this paper, the base-catalyzed hydrogen peroxide or t-butyl hydroperoxide mediated epoxidation of electron-poor olefins is subject to catalytic asymmetric induction.

Journal ArticleDOI
TL;DR: The chemisorption and catalytic properties of ruthenium-copper catalysts with a metal dispersion of the order of 1%, in which the dispersion refers to the fraction of metal atoms present in the surface, were investigated in this article.

Book ChapterDOI
TL;DR: In this article, the relativities of coordinated acetylene in terms of a qualitative molecular orbital picture have been analyzed and the role played by auxiliary ligands of transition metals in determining the paths of catalytic oligomerization has been discussed.
Abstract: Publisher Summary The chapter discusses facets associated with the nature of the interactions between acetylenes and transition metals and to the insertion reactions of complexes closely related to catalysis. Although only scattered data are available, attempts were made to give a consistent interpretation of the relativities of coordinated acetylene in terms of a qualitative molecular orbital picture. Studies on elementary reactions of acetylenes with metal complexes are now beginning to shed some light on the nature of activation caused by complication. This activation is not a simple process. Many low-valent d 8 -d 10 metal complexes and also some early transition metal compounds with higher oxidation state are capable of activating acetylenes. In the former complexes, interaction would lead to activation of an n 2- acctylcne ligand to an η-acetylene having some radical as well as some anionic character. The chapter also focuses on the complex chemistry and catalytic oligomerizations of allene. It also describes the importance of the role played by auxiliary ligands of transition metals in determining the paths of catalytic oligomerizations. In general the thermal reaction of allene gives a complex mixture of dimers, trimers, and higher oligomers including small amounts of spiro compounds.

Journal ArticleDOI
I. Schwager1, John F. Knifton1
TL;DR: In this article, a ligand-stabilized platinum(II)-group IVB metal halide complexes have been found to catalyze the homogeneous hydroformylation of olefins to aldehydes.

Journal ArticleDOI
TL;DR: In this article, it was shown that the selectivity for catalyzing non-destructive hydrocarbon reactions is often significantly tighter for a bimetallic catalyst than for its most active monometallic constituent.
Abstract: Three factors have greatly promoted the recent revival of interest in catalysis by alloys. The first was the finding that in industrial catalysis certain bimetallic systems are superior to monometallic catalysts. Sinfelt [1–5] had a particularly important share in the pioneering work supporting this finding. He showed that the selectivity for catalyzing nondestructive hydrocarbon reactions is often significantly tighter for a bimetallic catalyst than for its most active monometallic constituent. Even more important was the finding that bimetallic catalysts are frequently less susceptible to poisoning by, e.g., carbonaceous residues [1–6], As a consequence, their steady-state activity will be superior to that of monometallic catalysts even if the initial activity was lower.

PatentDOI
05 May 1976
TL;DR: In this paper, a hydroformylation process whereby rhodium complex catalyst and excess triorganophorus ligand are employed, under mild conditions of temperature and pressure, to produce aldehydic products rich in the normal isomer thereof, is described.
Abstract: A hydroformylation process whereby rhodium complex catalyst and excess triorganophorus ligand are employed, under mild conditions of temperature and pressure, to produce aldehydic products rich in the normal isomer thereof, the improvement representing the introduction and/or recycling of the rhodium complex in active form and soluble in a complex mixture of high boiling liquid condensation products rich in hydroxylic compounds