Showing papers on "Dehydrogenation published in 1976"
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.
247 citations
191 citations
TL;DR: In this article, the activity of PtRe catalysts on α- or γ-alumina has been determined for various reactions such as benzene hydrogenation, benzene-deuterium exchange, cyclopentane, and butane hydrogenolysis.
115 citations
114 citations
TL;DR: A series of diaminebis(2,2'-bipyridine) complexes of ruthenium(II), e.g., [Ru(bipy)2(en)]2+, has been prepared and the spectral and redox properties were investigated as mentioned in this paper.
Abstract: A series of diaminebis(2,2'-bipyridine) complexes of ruthenium(II), e.g., [Ru(bipy)2(en)]2+, has been prepared and the spectral and redox properties were investigated. The ethylenediamine and trans-1,2-diaminocyclohexane complexes undergo net four-electron oxidations, either chemically or electrochemically, giving the corresponding a,d-diimine complexes. The chemical and spectral properties of the cup'-diimine complexes are similar to those of [Ru(bipy)3]z+. Complexes containing 2-(aminomethyl)pyridine and 1,2-diamino-2-methyIpropane undergo net two-electron oxidations, in which the single CH2-NH2 linkage has undergone oxidative dehydrogenation to the imine. Electrochemical and titrimetric data (using Ce(1V)) in acetonitrile show that the diamine oxidative dehydrogenation reactions are initiated by oxidation of ruthenium(I1) to ruthenium(III), and that the reactions probably occur in a stepwise manner via monoimine intermediates.
97 citations
TL;DR: In this paper, the amounts of both the acidic and basic sites of two series of catalysts, TiO2-MoO3 and TiO 2-V2O5, with different compositions were measured by studying the adsorption of the basic and acidic molecules in the gas phase, using both the static and pulse methods.
Abstract: The amounts of both the acidic and basic sites of two series of catalysts, TiO2–MoO3 and TiO2–V2O5, with different compositions were measured by studying the adsorption of the basic and acidic molecules in the gas phase, using both the static and pulse methods. The acidity of TiO2–MoO3 catalysts is very high at Mo=40–60 atom%, though those of the TiO2-rich (Mo 80 atom%) catalysts are fairly low. The acidity of the TiO2–V2O5 increases steadily with the V2O5 content. The basicity of the catalysts is remarkably enhanced by the introduction of a small amount of MoO3 or V2O5. It can be said that the catalysts are basic at Mo<20 atom% or V<10 atom%, while the MoO3-rich or V2O5-rich catalysts are acidic. The vapor-phase oxidation of 1-butene, butadiene,and acetic acid, the dehydration and dehydrogenation of isopropyl alcohol (IRA), and the isomerization of 1-butene were carried out in the presence of an excess of air, and the relationship between the catalytic behavior and the acid-ba...
97 citations
TL;DR: In this article, the carbonization path of aromatic hydrocarbons catalyzed by alkali metals has been investigated to elucidate how aromatic coke were converted into the isotropic coke, compared to the same reaction catalyzed with aluminum chloride which gave the anisotropic needle-like coke.
89 citations
TL;DR: Deuterium and 14C-labeled isotopic tracers were used in kinetic experiments to study the oxidative dehydrogenation (OXD) of n-butenes to 1,3-butadiene over a MgFe2O4 catalyst in the temperature range 300-400 °C as mentioned in this paper.
73 citations
TL;DR: In this paper, the mixed oxides of antimony with Sn, Fe, Co, Ni, Mn, Zn, U, Ce, and Cd were tested as catalysts in the 1-butene oxidation.
51 citations
TL;DR: Magnesium ferrite (MgFe2O4) is a moderately selective catalyst for butadiene formation from n-butenes via Oxid dehydrogenation (OXD) as discussed by the authors.
47 citations
TL;DR: In this paper, Tetrangulol and its 3,8-dihydroxy-1-methyl isomer were obtained from 5-acetoxy-3-[β-(3-acetoxyphenyl)ethyl]-2-chloro-4-naphthoquinone.
Abstract: Hydroxybenz[a]anthracene-7,12-quinones can be prepared from 2-chloro-1,4-naphthoquinones by decarboxylative alkylation at C-3 with β-(3-acetoxyphenyl)propionic acids followed by treatment with sodium carbonate, which results in hydrolysis, cyclisation, and dehydrogenation. In this way tetrangulol and its 3,8-dihydroxy-1-methyl isomer were obtained from 5-acetoxy-3-[β-(3-acetoxy-5-methylphenyl)ethyl]-2-chloro-4-naphthoquinone.
Patent•
24 May 1976
TL;DR: In this article, two models have been developed that qualitatively explain the reactivity curves for hydrodesulfurization catalysts promoted by various amounts of transition metals (e.g., MoO3CoO).
Patent•
28 Oct 1976
TL;DR: In this paper, a catalytic composite comprising from about 0.01 to about 2.0 wt. % Group VIII metal and from 0.1 to about 1.1 wt % lithium impregnated on an alumina support is described.
Abstract: Paraffinic hydrocarbons are dehydrogenated in contact with a catalytic composite comprising from about 0.01 to about 2.0 wt. % Group VIII metal and from about 0.01 to about 0.1 wt. % lithium impregnated on an alumina support, said alumina having been hydrothermally treated in steam at a temperature of from about 800° to about 1200° C.
TL;DR: In this article, the catalytic activity of bimetallic catalysts is investigated in a conventional flow reactor at low conversions (<1%) to avoid mass and heat transfer limitations, and the activation energy found is 17 kcal/mol.
TL;DR: A set of metal carbonyl clusters, Ru, Os, Ir, and Ir(4)(CO)(12), has been evaluated as catalysts for a series of hydrocarbon reactions which comprise skeletal rearrangement, metathesis, dehydrogenation, hydrogenation, isomerization, and H-D exchange.
Abstract: A set of metal carbonyl clusters, Ru3(CO)12, Os3(CO)12, and Ir4(CO)12, has been evaluated as catalysts for a series of hydrocarbon reactions which comprise skeletal rearrangement, metathesis, dehydrogenation, hydrogenation, isomerization, and H-D exchange. None was especially effective as a hydrogenation catalyst even for olefins. Os3(CO)12 was a catalyst for H-D exchange between C6H6 and D2 at 195° but the ruthenium congener was inactive at temperatures below 175°, a temperature where ruthenium metal formed at an appreciable rate. Deuterium incorporation in the benzene was a single-step process. Ir4(CO)12 was an effective catalyst for the conversion of cyclohexadiene to cyclohexene and benzene. A similar reaction occurred with cyclohexene but the rate was extremely low at 160°. The ruthenium and osmium clusters catalyzed the isomerization of linear hexenes, with the former the more active. Relative rates for the hexenes were 1 > 2 > 3. At high temperatures, the osmium and iridium clusters catalyzed skeletal reactions of 2-hexene, as evidenced by the formation of pentenes, heptenes, heptanes, and small amounts of propane.
TL;DR: In this article, the reaction of 3-methylpentane, 1-methylcyclopentene, cis-and trans-3-methyl-2-pentenes, and trans-1-pentene, over a platinum black catalyst, in a pulse-microcatalytic system, in the presence of carrier gases with different hydrogen contents, was studied.
TL;DR: In this article, the reaction paths for cyclohexanol amination and dehydrogenation over Pt C catalysts have been studied in a continuous-flow microreactor, and the results show that in the absence of adsorbed hydrogen results in parallel path formation of cyclhexanone and phenol.
TL;DR: In this article, the catalytic decomposition of isopropyl alcohol (IPA) on V 2 O 5 and lithium doped V 2O 5 has been studied and the reaction is predominantly dehydration with very little dehydrogenation of IPA.
TL;DR: In this paper, a metal-dependent enzyme complex was found to be involved in the de-hydrogenation of cholest-7-en-3β-ol.
Abstract: The dehydrogenation of cholest-7-en-3β-ol to cholesta-5,7-dien-3β-ol by rat liver microsomal acetone powder has been known to involve the abstraction of 5α and 6α hydrogens, which were found in the water, of the medium.
It was proposed by other investigators that an enzyme-oxygen-metal complex may be involved in this dehydrogenation. This could then result in the reduction of the molecular oxygen to hydrogen peroxide. We have evaluated the possibility of the formation of hydrogen peroxide in the course of the transformation of 5α-[3α-3H]cholest-7-en-3β-ol to [3α-3H]cholesta-5,7-dien-3β-ol by a rat liver microsomal acetone powder in the presence of NAD+ and O2.
Hydrogen peroxide was not detected in the reaction mixture even though the sensitivity of the H2O2 detection method exceeded four times the calculated amount of hydrogen peroxide which could be produced in this reaction.
We have determined that the reaction is mitigated by a metal-dependent enzyme complex and the process requires the presence of EDTA. The involvement of a metal-enzyme complex is supported by the. observation that the desaturation is inhibited by 2,2′-dipyridyl, 1,10-phenanthroline and diethyldithiocarbamate. The reaction was also inhibited by horse radish peroxidase which suggested the participation of an enzyme-metal-oxygen complex. It was found that NADH promoted the dehydrogenation better than NAD+.
Attempts to dehydrogenate enzymatically 5α-[3α-3H]cholestan-3 β-ol failed. This tends to indicate the specificity of the enzyme system for 5α-cholest-7-en-3β-ol.
The free radical inhibitors diphenylamine, N-methylaniline and p-cresol exhibited a stimulatory effect on the reaction.
Based on these results, a tentative mechanism for the dehydrogenation of cholest-7-en-3β-ol is proposed.
TL;DR: The lamellar potassium graphite compound KC8 formed a well defined complex with benzene and tetrahydrofuran, and because of its high affinity for hydrogen causes conversion of benzene into biphenyl.
Abstract: The lamellar potassium–graphite compound KC8 forms a well defined lamellar complex with benzene and tetrahydrofuran, and because of its high affinity for hydrogen causes conversion of benzene into biphenyl.
Journal Article•
TL;DR: The enantioselective dehydrogenation of racemic (R-(+) and S-(−)) α-phenylethanol by RuCl2(PPh3)3 and (+)-neomenthyldiphenylphosphine at 180°C showed constant ratios of kR Ω(kS) in the absence of benzalacetone.
Abstract: The enantioselective dehydrogenation of racemic (R-(+) and S-(−)) α-phenylethanol by RuCl2(PPh3)3 and (+)-neomenthyldiphenylphosphine at 180°C showed constant ratios of kR⁄kS in the absence of benzalacetone. The kR⁄kS value increased almost linearly with the benzalaceton concentration and decreased with the larger amounts of the chiral phosphine under the present reaction conditions.