Hydrogenation Of Cyclopentadiene Research Articles

ЖИДКОФАЗНОЕ ГИДРИРОВАНИЕ ЦИКЛОПЕНТАДИЕНА НА МОДИФИЦИРОВАННЫХ СКЕЛЕТНЫХ НИКЕЛЕВЫХ КАТАЛИЗАТОРАХ

This paper presents the results of a study on the hydrogenation of cyclopentadiene on modified skeletal nickel catalysts. It is shown that the activity of multicomponent skeletal nickel catalysts in the hydrogenation of cyclopentadiene is largely due to the nature of the additives introduced into the initial alloy. The introduction of Cu, Pb, Ta, Zn, Mo-Cu, Bi and Mo into the alloy leads to an increase in the activity (W = 14-280 cm3/min g Ni) and selectivity (Ks = 0.93-0.99) of cyclopentadiene hydrogenation, additions of Cr, Ti, Sn and Cr-Cu have no significant effect. As a result, when cyclopentadiene is hydrogenated, an intermediate alkene, cyclopentene, is formed. This is due to the cyclic structure of cyclopentadiene, which causes the formation of identical cycloalkene molecules when hydrogen is added to any position. The saturation of cyclopentadiene is completely completed upon absorption of 1 mole of hydrogen, and cyclopentene can be obtained in high yield.

Synthesis of magnesium dicyclopentadienide catalyzed by titanium and vanadium derivatives

AbstractSynthesis of magnesium dicyclopentadienide from metal and cyclopentadiene in THF is effectively catalyzed by the derivatives of vanadium and titanium. The kinetics of the synthesis, as well as thermodynamic parameters of reagents adsorption on the magnesium surface, have been determined. The process catalyzed by titanium derivatives is accompanied by the quantitative hydrogenation of cyclopentadiene to cyclopentene whereas the catalysis by vanadium derivatives leads to hydrogen gas evolution. A number of reaction intermediates including Cp2TiCl, Cp2TiH2MgCl, Cp2Ti(cyclo‐C5H7) and Cp2V, were identified by the electron spin resonance method. The equilibrium constants, enthalpies and entropies of adsorption of metal halides on the magnesium surface were calculated. Copyright © 2001 John Wiley & Sons, Ltd.

The importance of sulfiding temperature of a HDS catalyst in the conversion of unsaturates in a benzene, toluene and xylene (BTX) feed

The effect of changing the sulfiding temperature ( T s) of a Co–Mo sulfide/ γ-Al 2O 3 hydrogenation catalyst in the range 200°C to 450°C, has been studied by the hydrogenation of cyclopentadiene, styrene alphamethylstyrene and indene impurities in a commercial plant feed at 200°C in a laboratory reactor. Transmission electron microscopy (TEM) was used to examine the morphology and structure of the catalyst and X-ray photoelectron spectroscopy (XPS) to ascertain the oxidation states of the Co and Mo. The performance of the catalyst peaked for T s around 400°C. For T s<300°C, the presence of catalyst material on the substrate could be deduced with TEM only from the grainy appearance of the support, but for higher T s, MoS 2 was seen arranged with its basal planes normal to the support. XPS revealed increased concentrations of Mo 4+, as MoS 2, with rising T s. The Co 2 p 3/2–S 2 p binding energy splitting increased from 616.0±0.2 eV at T s=200°C to 617.3±0.1 eV at T s=350°C, indicating that the Co increasingly decorated the edges of the MoS 2.

Catalytic hydrogenation and gas permeation properties of metal‐containing poly(phenylene oxide) and polysulfone

AbstractMetal‐containing polymers, PPO–DPP–Pd, PPO–CPA–Pd, PSF–DPP–Pd, PSF–CPA–Pd (DPP = diphenylphosphinyl, CPA = o‐carboxy phenyl amino), PPO–M (M = Pd, Cu, Co, Ni), and PSF‐Pd, were prepared by incorporating metal chloride with either modified or unmodified poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) and polysulfone (PSF). The Pd‐containing polymers exhibit catalytic activity in the hydrogenation of cyclopentadiene under mild conditions (40°C, 0.1 MPa) both in alcohol solution and in the gas phase. The selectivity in the hydrogenation of diene to monoene in the gas phase can be controlled by adjusting the hydrogen partial pressure. The metal‐containing polymers, PPO–M and PSF–Pd, can be cast easily into the membranes. The H2/N2 permselectivity for PPO–M is higher than that for unmodified PPO, whereas the permeability of H2 changes slightly. The H2 permeability and H2/N2 permselectivity for the PPO–Pd membrane are up to 67.5 barrers and 135, respectively. © 1993 John Wiley &amp; Sons, Inc.

Osmium ligand deficient clusters as catalysts for liquid phase hydrocarbon transformations

Reduction of OsO4 by molecular hydrogen in alkane (cycloalkane) or benzene media at 20–150 °C yields small osmium clusters of the Os1C0.34-0.48H0-0.6 composition with a specific surface area of 34–46 m2/g. The systems obtained are shown to be ligand deficient osmium clusters (LDC) of 7–16 A in diameter, stabilized by a small amount of carbonaceous ligands with Os-Os = 2.68-1.70 A and Os-C = 2.11-2.19 A. The characteristics of these chemically prepared Os-LDC are similar to those of Ni- and Co-LDC, prepared by a vapour phase synthesis. The novel Os-LDC effectively catalyze hydrogenolysis of alkanes and cycloalkanes at 100–150 ° C and initial H2 pressure of 5 MPa, hydrogenation of cyclopentadiene and arenes at 20 ° C, multiple H/D exchange between CH4 and D2 at 100–120 ° C and methanation of CO2 at 150–180 ° C.

Role of Carriers in the Selective Hydrogenation of Cyclopentadiene Over Supported Palladium Catalysts

Several supported palladium catalysts were prepared and thier effects on the kinetic behaviors in the selective hydrogenation of cyclopentadiene were studied. Experiments show that cyclopentadiene inhibits the hydrogenation of cyclopentene. Data based on kinetic analysis indicate that the coordination of cyclopentadiene is much stronger than that of cyclopentene which should be the main factor of this inhibition reaction. Catalyst carriers via thier ligand effects can influence the ratio of the coordination equilibrium constants K-D/K-E and the rate constants K-2/K-4, which in turn change the selectivities and activities of catalyets.

Hydrogenation of cyclopentadiene in the presence of isoprene and 1,3-pentadiene on a Pd-Ru membrane catalyst

1. The hydrogenation of cyclopentadiene, containing up to 25% of isoprene and 1.5% of 1,3-pentadiene, on a membrane catalyst composed of Pd alloy containing 9.8% Ru, proceeds at the same rate and selectivity in cyclopentene as does pure cyclopentadiene. 2. The relative adsorption coefficients of isoprene (0.6), 1,3-pentadiene (1.3), and cyclopentadiene (1) were determined.

Monomerization of dicyclopentadiene and hydrogenation of cyclopentadiene in a stream of methane over palladium-ruthenium alloy

1. Methane can be used as a heat-transfer agent for the monomerization of dicyclopentadiene and as carrier gas for the hydrogenation of cyclopentadiene (CPD) to cyclopentene at membrane catalysts consisting of a palladium alloy with 9.8% of ruthenium. 2. Increases in the selectivity and in the yield of cyclopentene were found during hydrogenation of CPD with hydrogen passing through the membrane catalyst compared with the delivery of a mixture of CPD vapor and hydrogen at the same catalyst.

Membrane catalysts in selective hydrogenation of certain products of pyrolysis of petroleum hydrocarbons

Results of studies of the applicability of membrane catalysts made of Pd and Pd-Ag alloys to the selective hydrogenation of acetylene to ethylene and of cyclopentadiene to cyclopentene are reported. The hydrogenation of naphthalene to tetralin and the conversion of C/sub 8/ to C/sub 12/ cyclopolyolefins were also studied. Data are given to show that it is possible to selectively hydrogenate acetylene in mixtures with ethylene and ethane using the hydrogen permeable catalysts. In the presence of the alloy catalysts, hydrogenation of cyclopentadiene was carried out with full conversion of the original hydrocarbon and selectivity for cyclopentene of 0.94. Hydrogenation of cyclooctadiene yielded mainly cyclooctane, and cyclododecadiene resulted from hydrogenation of cyclododecatriene. (BLM)

Effect of dentate number of anchored phosphine ligands on the composition and catalytic properties of their palladium complexes

Mono-, di- and triphosphine ligands anchored by a Si−C bond to the surface of silica have been synthesized. Complexes of Pd(II) and Pd(O) with these ligands have been obtained. On the basis of elemental analysis and UV spectroscopy, structures of the complexes formed are suggested. The catalytic properties of the above complexes in the selective hydrogenation of cyclopentadiene are compared.

Effect of hydrogen transfer through a membrane catalyst from a Pd-Ru alloy on the rate of dehydrogenation of isopropanol and hydrogenation of cyclopentadiene

1. 1. Hydrogen transfer to the zone of hydrogenation of cyclopentadiene through a membrane catalyst from a Pd alloy with 10 vol. % Ru increases the rate and selectivity of hydrogenation to cyclopentene, compared with the experiment carried out at the same temperature and partial reagent pressure, but without hydrogen transfer to the membrane catalyst. 2. 2. Joining dehydrogenation of isopropyl alcohol and hydrogenation of cyclopentadiene increases even more the rate of both reactions, the selectivity of conversion of cyclopentadiene to cyclopentene and increases the amount of hydrogen formed during dehydrogenation of alcohol that is passed through the membrane.

ChemInform Abstract: HYDROGENATION OF CYCLOPENTADIENE ON A NICKEL CATALYST

AbstractDie Hydrierung von Cyclopentadien zu Cyclopentan mit Wasserstoff verläuft über Cyclopenten als Zwischenstufe.

Hydrogenation of cyclopentadiene on a nickel catalyst

AbstractThe hydrogenation of cyclopentadiene on Ni catalyst was carried out with a fixed bed reactor.The initial reaction rates were expressed by the following equations. magnified imageThe activation energies of overall‐and surface‐reaction rates were, respectively, 1.9 and 6.5 kcal/mol and the heats of adsorption of hydrogen and cyclopentadiene were, respectively, 5.6 and 1.6 kcal/mol.The hydrogenation of cyclopentadiene on Ni catalyst is a consecutive reaction passing through cyclopentene, where the activation energy of the 1st stage is higher than that of the 2nd one, namely, E1 &gt; E2. At the lower ratio of PH/PC, cyclopentene is produced with 100% selectivity, whereas, increasing PH/PC or W/F0, the selectivity decreases. At the intermediate reaction temperature, there appears the minimum selectivity. This phenomenon is considered to be due to E1 &gt; E2.

Influence of amines on the activity and selectivity of a skeletal nickel catalyst

1. The influence of amines and heterocyclic compounds containing nitrogen on the rate and selectivity of the hydrogenation of cyclopentadiene, tolane, and dimethylvinylethynylcarbinol was studied in the presence of a skeletal nickel catalyst. 2. In the presence of methylamine, butylamine, ethylenediamine, hexamethylenediamine, piperidine, 4-ethylpyridine, benzotriazole, and quinoline methiodide, cyclopentadiene, tolane, and dimethylvinylethynylcarbinol are selectively hydrogenated on a skeletal nickel catalyst to the corresponding monoolefinic compounds. Such selectivity may be explained by the reversible adsorption poisoning of the catalyst. 3. In the presence of α-naphthylamine, diethylamine, diphenylamine, and 2-ethylpyridine, the hydrogenation of cyclopentadiene, tolane, and dimethylvinylethynylcarbinol is nonselective; the monoolefinic compounds formed are hydrogenated further, forming the fully hydrogenated compounds.

Effect of acidity upon activity of oxide catalysts. Part II. Dehydration of isopropyl alcohol

Many pure and multicomponent inorganic aerogels have been prepared using the autoclave method which has been recently largely developed in this laboratory. The first step of the process consists in the preparation of a mixed alcogel (in the case of a nickel oxide-alumina aerogel for example). Organic derivatives of aluminium and nickel, both dissolved in methanol, are coprecipitated as alcogels by addition of water. In the second step the solvent is evacuated under hypercritical conditions in an autoclave, in order to avoid the collapse of the texture. If the autoclave is then flushed out by hydrogen instead of nitrogen, metallic nickel-on alumina aerogel is directly obtained, rather than nickel oxide-on alumina aerogel.This procedure gives solids with a large pore volume and high surface areas. These aerogels are amorphous provided some conditions during hydrolysis are satisfied and in particular the proportion of water and the pH.The NiO-Al2O3 aerogels exhibit good catalytic activities and selectivities in the partial oxidation of olefins (isobutylene). When a nickel oxide on silica-alumina aerogel, prepared by the autoclave process, is used as a catalyst for the partial oxidation of an olefin (isobutylene), dimerization of this reactant occurs showing in this case the effect of the silica-alumina aerogel support, whereas in the case of NiO-alumina aerogel partial oxidation without dimerization of the olefin is recorded.Metal on oxide aerogels are good hydrogenation-dehydrogenation catalysts. Thus, nickel on alumina aerogel is very selective in the hydrogenolysis of ethylbenzene into benzene, whereas copper on alumina aerogel gives 100% selectivity in the hydrogenation of cyclopentadiene into cyclopentene.Nickel on alumina aerogel provides also a good mean of testing the hydrogen spillover phenomena in an olefin hydrogenation catalyzed reaction. Infra-red investigations of the spilt-over hydrogen species show that this species is linked to the alumina as a surface OH group.Another kind of multicomponent catalyst which can be prepared by the autoclave process is a nickel on molybdenum oxide aerogel. Pure molybdenum oxide aerogel shows a very good electrical conductivity so it may be expected that Ni dispersed on MoO2 aerogel may be used as a fuel cell electrode component. The effect of the amount of Ni on the textural and electrical properties of the Ni-MoO2 aerogel is described.

On theory of chemisorption

Many pure and multicomponent inorganic aerogels have been prepared using the autoclave method which has been recently largely developed in this laboratory. The first step of the process consists in the preparation of a mixed alcogel (in the case of a nickel oxide-alumina aerogel for example). Organic derivatives of aluminium and nickel, both dissolved in methanol, are coprecipitated as alcogels by addition of water. In the second step the solvent is evacuated under hypercritical conditions in an autoclave, in order to avoid the collapse of the texture. If the autoclave is then flushed out by hydrogen instead of nitrogen, metallic nickel-on alumina aerogel is directly obtained, rather than nickel oxide-on alumina aerogel.This procedure gives solids with a large pore volume and high surface areas. These aerogels are amorphous provided some conditions during hydrolysis are satisfied and in particular the proportion of water and the pH.The NiO-Al2O3 aerogels exhibit good catalytic activities and selectivities in the partial oxidation of olefins (isobutylene). When a nickel oxide on silica-alumina aerogel, prepared by the autoclave process, is used as a catalyst for the partial oxidation of an olefin (isobutylene), dimerization of this reactant occurs showing in this case the effect of the silica-alumina aerogel support, whereas in the case of NiO-alumina aerogel partial oxidation without dimerization of the olefin is recorded.Metal on oxide aerogels are good hydrogenation-dehydrogenation catalysts. Thus, nickel on alumina aerogel is very selective in the hydrogenolysis of ethylbenzene into benzene, whereas copper on alumina aerogel gives 100% selectivity in the hydrogenation of cyclopentadiene into cyclopentene.Nickel on alumina aerogel provides also a good mean of testing the hydrogen spillover phenomena in an olefin hydrogenation catalyzed reaction. Infra-red investigations of the spilt-over hydrogen species show that this species is linked to the alumina as a surface OH group.Another kind of multicomponent catalyst which can be prepared by the autoclave process is a nickel on molybdenum oxide aerogel. Pure molybdenum oxide aerogel shows a very good electrical conductivity so it may be expected that Ni dispersed on MoO2 aerogel may be used as a fuel cell electrode component. The effect of the amount of Ni on the textural and electrical properties of the Ni-MoO2 aerogel is described.

Kinetics of the hydrogenation of cyclopentadiene and gyclopentene over raney nickel

1. The kinetics of the hydrogenation of cyclopentadiene and cyclopentene over Raney nickel were investigated. 2. Both reactions are of zero order and they have the same temperature coefficient. At the same temperature the rate constants for the hydrogenation of cyclopentadiene are higher than those for the hydrogenation of cyclopentene, but the two reactions have the same activation energy.

Hydrogenation of cyclopentadiene in binary mixtures with unsaturated hydrocarbons over palladium and platinum blacks

1. A study was made of the selectivity of the hydrogenation of cyclopentadiene into cyclopentene in binary mixtures with unsaturated hydrocarbons in presence of palladium and platinum blacks. 2. It was found that, like Raney nickel. palladium black brings about selective hydrogenation of cyclopentadiene in its binary mixture with cyclohexene, but nonselective hydrogenation in mixtures with styrene. Palladium black differs from Raney nickel in that it does not bring about selective hydrogenation of cyclopentadiene in its mixtures with diphenylacetylene. In presence of platinum black, cyclopentadiene is not hydrogenated selectively in binary mixtures with cyclopentene and 1-octene.

Stagewise character of the hydrogenation of the double bonds of cyclopentadiene over raney nickel

1. An investigation was made into the kinetics of the hydrogenation of cyclopentadiene in presence of Raney nickel at 25° and normal pressure in alcoholic and hydrocarbon solutions. 2. It was shown that cyclopentadiene is rapidly hydrogenated to cyclopentane in methyl, ethyl, and isobutyl alcohols. 3. In aromatic, hydroaromatic,aliphatic hydrocarbon solutions, cyclopentadiene is rapidly hydrogenated only as far as cyclopentene, and the second molecular proportion of hydrogen adds very slowly. 4. In all solvents examined, the conjugated double bands of cyclopentadiene are hydrogenated successively. In hydrocarbon solvents the two-stage character of the process can be demonstrated also by kinetic methods. 5. Both in alcohol and in hydrocarbon solvents cyclopentene can be obtained from cyclopentadiene if the hydrogenation is arrested after the Addition of one molecular proportion of hydrogen.

Preparation of cyclopentene from cyclopentadiene

A convenient laboratory method is proposed for the preparation of cyclopentene by the hydrogenation of cyclopentadiene. Yields of up to 70% are obtained.