Showing papers on "Dehydrogenation published in 1983"
TL;DR: The thermal evolution of acetylene and ethylene and their deuterated counterparts on a palladium surface has been studied by high-resolution electron energy loss spectroscopy in the temperature range 150-500 K as discussed by the authors.
209 citations
198 citations
TL;DR: The interaction of hydrogen with metals is the cause or basis of a host of phenomena ranging from the chemisorption of hydrogen on the surface, its dissolution in the metal, catalytic reactions involving hydrogen as a reactant or as an astoichiometric component, etc., to the formation of metal hydrides as discussed by the authors.
Abstract: The interaction of hydrogen with metals is the cause or basis of a host of phenomena ranging from the chemisorption of hydrogen on the surface, its dissolution in the metal, catalytic reactions involving hydrogen as a reactant or as an astoichiometric component, etc., to the formation of metal hydrides. Hydrogen -induced corrosion and hydrogen embrittlement of steel are well known in chemical process industry and metallurgy. Catalytic reactions on metal or metal-oxide catalysts in the presence of hydrogen, often under pressure, are some of the major chemical, petroleum, and petrochemical processes of today, e.g., ammonia, methanol, Fischer-Tropsch, Oxo and other syntheses, hydrogenation of oils and fats, catalytic reforming, hydrode-sulfurization/hydrotreating, hydrocracking, and hydrogenation/ dehydrogenation.
130 citations
TL;DR: In this article, the pore structure of the crystalline zirconium phosphate (produced according to specific manufacturing procedures) appears to be particularly suitable for this reaction in the sense that it is a selective catalyst.
119 citations
TL;DR: In this article, TPSSIMS and TPDP(111) were combined to probe the structure and kinetics of adsorbed species, and the results demonstrate the power of combining TPD and TPSSimS to explore the structure of an adorbed hydrocarbon parent.
109 citations
TL;DR: An infrared spectroscopic study was made of the adsorbed species and the gas-phase products from the dehydrogenation and dehydration reactions of 2-propanol over CeO2 catalysts calcined at different temperatures as mentioned in this paper.
103 citations
TL;DR: In this paper, the acid-base solid, TiO2ZrO2, was examined as a potential catalyst for nonoxidative dehydrogenation of ethylbenzene.
98 citations
TL;DR: In this paper, selective catalytic dehydrogenation (up to 9 turnovers) of cycloalkanes CnH2n(n= 6, 7, and 8) was achieved, under mild conditions (30-80 °C), using dilute (ca. 3 mM) solutions of the bis(phosphine) rhenium heptahydrides (Ar3P)2ReH7(Ar =p-F-;C6H4, Ph, and p-Me-C 6H4) in the cyclo
Abstract: Selective catalytic dehydrogenation (up to 9 turnovers) of cycloalkanes CnH2n(n= 6, 7, and 8) to the corresponding cycloalkenes is achieved, under mild conditions (30–80 °C), using dilute (ca. 3 mM) solutions of the bis(phosphine) rhenium heptahydrides (Ar3P)2ReH7(Ar =p-F-;C6H4, Ph, and p-Me-C6H4) in the cycloalkane, with an olefin as the hydrogen acceptor.
97 citations
87 citations
TL;DR: Turnover rates for the catalytic dehydrogenation of formic acid (HCOOH) on Cu SiO 2, Cu Al 2 O 3, and Cu powder between 380 and 500K are reported as mentioned in this paper.
66 citations
TL;DR: The most active homogeneous catalyst known for the selective dehydrogenation of 2-propanol has been found to form from Rh2(OAc)4 by adding PPh3 in situ as mentioned in this paper.
15 Mar 1983
TL;DR: In this paper, the cyclopentane and cyclohexane cations were generated by irradiation at 77 K of the solutes contained in a CF 3 CCl 3 matrix.
Abstract: ESR studies of cyclopentane, cyclohexane, cyclopentene, cyclohexene, 1,4- and 1,3-cyclohexadiene cations have been performed in order to elucidate their structures and their reactions, particularly those induced by visible light. The cations were generated by irradiation at 77 K of the solutes contained in a CF 3 CCl 3 matrix. At low temperature (6 K) the cyclopentane cation has a low (C s ) symmetry characterised by a = 22.4 G (2H). At higher temperature (113 K) all ten hydrogens interact equally with a = 6.3 G. The cyclohexane cation has a = 43 G (611) at 141 K characteristic of a chair form with p = 0.085 on each of the six equatorial hydrogen atoms. The cyclohexane cation undergoes a dehydrogenation reaction under the action of visible light resulting in the formation of the cyclohexene cation. New reaction mechanisms are proposed for this case and for the decomposition of the unsaturated hydrocarbon cations under study.
Patent•
22 Mar 1983
TL;DR: In this paper, a new catalyst for converting hydrocarbons was proposed, which comprises a platinum group component, a Group IVA component, especially tin, an alkali or alkaline earth component, more than 0.2 weight %, calculated on an elemental basis, of a halogen component and a porous carrier material.
Abstract: This invention relates to a new catalyst for converting hydrocarbons. The catalyst comprises a platinum group component, a Group IVA component, especially tin, an alkali or alkaline earth component, more than 0.2 weight %, calculated on an elemental basis, of a halogen component and a porous carrier material, wherein the atomic ratio of the alkali or alkaline earth component to the platinum group component is more than 10. The catalyst is particularly useful for dehydrogenating paraffins having from 2 to 5 or more carbon atoms to the corresponding mono-olefins, or for dehydrogenating mono-olefins having from 3 to 5 or more carbon atoms to the corresponding di-olefins.
TL;DR: In this article, the adsorption behavior of ethylene glycol and its derivatives is discussed on the basis of the literature data and new experimental observations and results obtained by different methods (pure electrochemical, radiotracer) are compared.
TL;DR: In this paper, the authors propose a structural model for catalytic anisotropic anisotropy of oxides in simple or oxidative dehydrogenation, dehydration, and oxidation reactions based on crystallographic data and on known shapes and dimensions of organic molecules.
TL;DR: In this article, it has been demonstrated that oxidation reactions of organic compounds over H3PMo12O40 and its alkali salts are classified into two prototypes: surface redox properties of catalysts and the bulk properties.
Abstract: It has been demonstrated that oxidation reactions of organic compounds over H3PMo12O40 and its alkali salts are classified into two prototypes. In the first type reactions, the surface redox properties of catalysts are important, and in the second type the bulk properties. Oxygen-addition reactions like methacrolein to methacrylic acid are an example of the former, and oxidative dehydrogenation is the latter example.
TL;DR: In this article, Fourier transform mass spectrometry is applied to study the structures of NiC/sub n/H/sub 2n+ complexes generated from reactions of Ni+ with a variety of hydrocarbons and demonstrate that different isomeric structures can readily be distinguished both by collision-induced dissociation and by specific ion-molecule reactions.
Abstract: In this paper, Fourier transform mass spectrometry is applied to study the structures of NiC/sub n/H/sub 2n/+ complexes generated from reactions of Ni+ with a variety of hydrocarbons and demonstrate that different isomeric structures can readily be distinguished both by a collision-induced dissociation and by specific ion-molecule reactions. Evidence is provided for four unique structures of NiC/sub 4/H/sub 8/+ generated from reactions of Ni+ with butane, hexane, 2,2-dimethylpropane, and cyclopentanone. Dehydrogenation reactions of Ni+ with n-alkanes yield bis(olefin) complexes that are distinguishable from their isomeric monoalkene complexes. Ni+ is found to be highly selective for cleaving internal bonds and highly selective against insertion into terminal C-C bonds. Dehydrogenation becomes more competitive with alkane elimination when ..beta..-hydride transfers from secondary carbons are involved instead of from primary carbons.
Patent•
19 May 1983
TL;DR: In this paper, a new process for dehydrogenating hydrocarbons utilizing a catalyst comprising a platinum group component, an alkali or alkaline earth component and a porous support material was proposed.
Abstract: This invention relates to a new process for dehydrogenating hydrocarbons utilizing a catalyst comprising a platinum group component, an alkali or alkaline earth component and a porous support material. After the catalyst is used to dehydrogenate hydrocarbons it is contacted in a catalyst regeneration zone with a halogen component to produce a regenerated catalyst containing added halogen component, which regenerated catalyst can then be reused to dehydrogenate hydrocarbons. The added halogen component increases the catalyst's activity and stability in the dehydrogenation process.
Patent•
22 Feb 1983
TL;DR: In this article, an integrated two-step process was proposed to convert unsaturated aldehydes, particularly acrolein and methacrolein, to unsaturated acids.
Abstract: Alkanes, particularly propane and isobutane, are converted to unsaturated aldehydes, particularly acrolein and methacrolein, in an integrated two-step process wherein the alkane is dehydrogenated in a first step to the corresponding olefin, hydrogen, and by-products and the reaction effluent is passed directly into a second step where the olefin is oxidized to the corresponding unsaturated aldehyde without significant oxidation of the hydrogen and by-products Some of the by-products of the first stage reactions, or the hydrogen, may be removed from the reaction effluent before it is passed to the second step The aldehydes and by-products of the oxidation may be separated and the unreacted olefin and alkane recycled to the first step Alternatively, the effluent from the second step may be used as feed to a further oxidation step for conversion of the unsaturated aldehyde to the corresponding unsaturated acid
TL;DR: Turnover rates for the catalytic dehydrogenation and dehydration of formic acid (HCOOH) on NiSiO2 and Ni and CuNi powders between 390 and 490K are reported in this article.
TL;DR: The surface coverage of sulfur on Ni(100) was varied between 0 and 8.0×1014 atoms/cm2 in order to quantify its effect on both CO adsorption and CH3OH dehydrogenation as studied by temperature-programmed reaction spectroscopy.
Abstract: The surface coverage of sulfur on Ni(100) was varied between 0 and 8.0×1014 atoms/cm2 in order to quantify its effect on both CO adsorption and CH3OH dehydrogenation as studied by temperature‐programmed reaction spectroscopy. At a sulfur coverage of ns=4.8×104 atom/cm2 the CO desorption peak characteristic of clean Ni(100) was extinguished and was replaced by two distinct peaks at lower temperature (β1 and β2). Also at this coverage the methoxy intermediate became stable above room temperature, and the dehydrogenation selectivity shifted toward H2CO. At θs=0.38 only partial dehydrogenation of CH3OH to H2CO and H2 occured, and the amount of H2CO formed was maximized. It was found that CO preadsorbed into fourfold hollow sites poisoned the partial dehydrogenation in a one‐to‐one fashion by blocking formation of adsorbed methoxy intermediates. The results also indicate that short range interactions between adsorbed CO and S are not responsible for the sharp decrease in the saturation coverage of CO at low co...
TL;DR: In this paper, the acid-base properties of ZrO2-SnO2 with different compositions have been measured by the indicator method and the adsorption with NH3 and CO2 and the catalytic activities studied.
Abstract: The acid-base properties of ZrO2–SnO2 with different compositions have been measured by the indicator method and the adsorption with NH3 and CO2 and the catalytic activities studied. The ZrO2–SnO2 (atomic ratio=9 : 1) catalyst which was found to have the highest acid strength and the maximum acid amount exhibited the highest activities for the isomerization of cyclopropane and the dehydration of 2-butanol. The activities of the catalysts with different compositions for the two reactions correlated with the acidic properties. On the other hand, the activities for the isomerization of 1-butene and the decomposition of diacetone alcohol (4-hydroxyl-4-methyl-2-pentanone) correlated with the basic properties. The activity for the dehydrogenation of 2-butanol was found to increase with an increase of the SnO2 content. The active sites on the ZrO2–SnO2 catalysts are discussed.
TL;DR: The second component of a binary palladium alloy affects its catalytic activity in hydrogen addition and subtraction reactions with organic compounds as discussed by the authors, and the principal product of diene hydrogenation when hydrogen permeates through a membrane catalyst is not a saturated hydrocarbon but the corresponding olefin from which polymers can be synthesized.
Abstract: The nature and the concentration of the second component of a binary palladium alloy affects its catalytic activity in hydrogen addition and subtraction reactions with organic compounds. Hydrogen permeation across a palladium alloy catalyst enhances the rate and selectivity of hydrogenation compared with what is observed when the compound being hydrogenated is mixed directly with hydrogen. The principal product of diene hydrogenation when the hydrogen permeates through a membrane catalyst is not a saturated hydrocarbon but the corresponding olefin from which polymers can be synthesized. The rate of hydrogen atom addition to the diene molecules on the palladium alloy surface is higher than the rate of hydrogen atom recombination and desorption in the form of hydrogen molecules.
TL;DR: The ZrMn1 + xFe1 + y−H2 systems with x,y = 0.11-0.53 and x + y ⩽ 0.64 were studied as a function of composition, temperature, and hydrogen dissociation pressure (0.01-50 atm) as discussed by the authors.
Abstract: The ZrMn1 + xFe1 + y−H2 systems with x,y = 0.11-0.53 and x + y ⩽ 0.64 were studied as a function of composition, temperature (0–200 °C) and hydrogen dissociation pressure (0.01–50 atm). The hyperstoichiometric manganese and iron appear to substitute at the zirconium sites with a net effect of raising the vapor pressure of their hydrides to 500–1500 times that of ZrMn2 hydride. The ZrMn1.27Fe1.58 alloy does not absorb measurable quantities of hydrogen, presumably because of the very high vapor pressure of its hypothetical hydride. The hydrides of ZrMn1.22Fe1.11 and ZrMn1.11Fe1.22 alloys have dissociation pressures in the range of 1–2 atm at room temperature. The hydrogen capacities of these alloys are quite high, e.g. about 185 cm3 g−1. Enthalpies and entropies of dehydrogenation, obtained from a van't Hoff plot of ln pH2versus 1/T, are very low, being 9.8–13.4 kJ (mol H2)−1 and 42–53 J (mol H2)−1 K−1 respectively. The kinetics of hydrogen absorption and desorption are extremely fast.