Search

The effect of Ti and Al incorporation to FSM-16 framework as the support of Ni catalysts on their catalytic performance in the reaction of dry reforming of methane (DRM) was investigated. A series of Ni/M-FSM-16 (M = Al, Ti) with M/Si molar ratio = 100, 50, 20 were synthesized via double-solvent impregnation of Nickel. Fresh catalysts were characterized using N2 adsorption/desorption, XRD, FTIR, FE-SEM, H2-TPR analyses. The prepared catalyst went through DRM reaction at 750, 800, and 850 °C. The spent catalysts of best catalytic performance, i.e. Ni/Al50-FSM-16 and Ni/Ti100-FSM-16, were analyzed by FT-IR and O2-TPO to characterized carbonaceous deposits. Based on TPR results, the promotion of DRM performances was related to the strength of Ni interaction with supports to which Ti or Al was incorporated. Conversion of CH4 and CO2, and H2/CO ratio of the products via Ni/Al50-FSM-16 catalyst were promoted by 95%, 83%, 25% with respect to Ni/FSM-16 at 850 °C, respectively.

Enantioselective difunctionalization of alkenes constitutes an efficient strategy to assemble complex chiral molecules from simple racemic or achiral starting materials. Here we present an intermolecular nickel-catalysed enantioselective 1,1-arylboration of unactivated terminal alkenes. The high regio- and enantioselectivities of the reactions arise from a judicious choice of the nickel catalyst rather than the incorporation of a directing group. Moreover, excellent regioselectivities can also be obtained from the reactions of allylbenzenes. We also conducted a series of stereospecific downstream transformations for the enantioenriched secondary boronic esters. These examples represent an efficient catalyst-controlled enantioselective 1,1-difunctionalization of unactivated alkenes. Difunctionalization of alkenes can afford useful building blocks from readily available starting materials, but these reactions often show limitations in olefin scope. This work presents a catalyst-controlled enantioselective 1,1-arylboration of unactivated alkenes that is independent of directing groups.

The CO2 reforming reactions of methane were carried out using three types of Ni/δ-Al2O3s and the effects of the addition of CeO2 were examined. In this study, the addition of a high weight percentage of CeO2 focused on reducing the amount of deposited carbon. It was revealed that a high Al2O3 surface area was necessary for the effective reduction of the deposited carbon by the addition of 50% CeO2 with the lowest conversion decrease. The addition of CeO2 and ZrO2 (Ni/Al2O3(A)-CeO2(45)-ZrO2(5)) further decreased the deposited carbon to 0.14 mmol per 1 mol of produced CO at 1073 K.

Highly efficient cross-couplings of diarylborinic acids with aryl tosylates and sulfamates are reported for construction of biaryls using a tri(4-methoxyphenyl)phosphine-supported nickel catalyst system: Ni[P(4-MeOC6H4)3]2Cl2/2P(4-MeOC6H4)3 in the presence of K3PO4·3H2O in toluene. A variety of unsymmetrical biaryls could be obtained in good to excellent yields with 1.5–3 mol% or 3–5 mol% catalyst loadings for aryl sulfamates and tosylates, respectively. In sharp contrast to the conventional nickel-catalyzed Suzuki coupling with arylboronic acids, arylsulfamates unexpectedly displayed a higher reactivity than the corresponding tosylates in coupling with diarylborinic acids catalyzed by the nickel/phosphine catalyst system.

A method for making an “aluminum – carbon nanofibers” composite material is presented. Good distribution of carbon structures is provided by synthesizing nanofibers from a gas phase directly on the surface of matrix metallic particles and adding a nickel catalyst.

Palm mid fraction produced from Malaysian palm olein was hydrogenated using industrial catalyst (PRICAT 9910) on both pilot and industrial units. Effects of hydrogenation parameters, including temperature, catalyst concentration, reaction time, and circulation rate on final fatty acid composition and trans-fatty acid content were investigated. Mass transfer limitations were indicated particularly in the industrial plant runs. Mass transfer coefficient in the gas–liquid transfer was identified for various circulation rates. The combined mass transfer resistance at the liquid–solid interface and within the catalyst pellet was calculated as a function of different temperatures and circulation rates.

The formation of the carbon–carbon bond is a fundamental reaction in modern organic synthesis, which is mediated by transition-metal catalysts. Over the past 30 years, the carbon–carbon coupling reactions, particularly the Kumada-Tamao-Corriu coupling reaction, have been dramatically expanded providing a simple methodology for synthetic organic chemistry. So, this review highlights several recent and major developments of carbon–carbon bond-forming reactions by alkylation, alkenylation, arylation, and heteroarylation of Grignard compounds using different catalysts and ligands.

A nickel catalyst showed a considerable selectivity to propylene glycol (up to 98%) at 30% glycerol conversion, under moderate hydrogenation conditions: 200 °C reaction temperature, 20–25 bar hydrogen pressure, 5 wt% catalyst and unprecedented low reaction time of 8 h.

A simple method to prepare eggshell Ni/MgO-Al2O3 catalyst was developed. In partial oxidation of methane, eggshell Ni/MgO-Al2O3 showed better reactivity and stability than the uniform one, even than eggshell Ni/Al2O3.

The effect of La2O3, K2O and Li2O on the properties and catalytic performance of silica-supported nickel catalysts for the hydrogenation of m-dinitrobenzene was investigated. The catalysts promoted with La2O3, Li2O and K2O showed better catalytic performance than the catalyst without promotion, especially the ones co-promoted with La2O3 and K2O or Li2O.

Methanation is a classical reaction in heterogeneous catalysis and significant effort has been put into improving the industrially preferred nickel-based catalysts. Recently, a computational screening study showed that nickel-iron alloys should be more active than the pure nickel catalyst and at the same time less expensive. This was previously verified experimentally for pure CO hydrogenation. In this study, the improved activity is also verified for CO2 hydrogenation as well as for simultaneous CO and CO2 hydrogenation.

Carbon nanofibers (CNFs) with a uniform diameter of ca. 30 nm have been grown via catalytic decomposition of C2H6/H2 mixture over a nickel (1 wt.%) catalyst supported on graphite microfibers which constitutes the macroscopic shape of the final C/C composite. The productivity reached 50 g of CNFs / g of Ni / h on stream and is among the highest reported to date. The resulting composite consisting in a web-like network of CNFs covering the starting catalyst was characterized by SEM and TEM in order to get more insight on the relationship between the starting nickel catalyst particles and the as-grown CNFs. Apparently the CNFs growth proceeds from different mechanisms: base-growth mechanism involving especially the large nickel particles, tip-growth mechanism involving the smaller nickel particles and tip/octopus-growth mechanism, the most frequent involving all particles. The restructuration of the nickel particle from a globular to a more faceted structure seems to be the key step to produce an extremely large quantity of CNF with yields up to 100 wt.% after 2 h of synthesis.

An easily prepared and reusable Ni(OH)2 catalyst for the oxidation of benzylic and allylic alcohols by molecular oxygen has been developed.

The effects of the modification conditions on the hydrogenation rate and the enantio-differentiating ability (e.d.a.) for the enantio-differentiating hydrogenation of methyl acetoacetate were studied over an (R, R)-tartaric acid–NaBr-in-situ-modified nickel catalyst. It was revealed that a tartaric acid modification increased the hydrogenation rate irrespective of the presence of the auxiliary modifier, NaBr. In the presence of the tartaric acid, NaBr would have two roles, i.e., Na+ activates the enantio-differentiating sites through the interaction with tartaric acid, and Br− deactivates both the enantio-differentiating sites and non-enantio-differentiating sites. The e.d.a. values and the hydrogenation rate would be determined by the combination of these effects of Na+ and Br−.

Preparation of Polyphenylenes with Higher Molecular Weights via Dehalogenative Polycondensation Using Magnesium and Aggregating Property of the Polymer in Solutions

Superfine Ni/BaTiO3 catalysts were prepared by impregnation method and used successfully for CO2 reforming CH4 to syngas. The effects of preparation method and the temperatures of calcination, reduction and reaction on the catalytic activity of the Ni/BaTiO3 system were investigated.

Poly(3-alkoxythiophene)s with moderately high molecular weights, which exhibit good solubility and film-forming ability, were successfully synthesized by the nickel (0) coupling reaction in good yields. The introduction of a branched side chain resulted in a molecular weight higher than that of the straight one. Broad photoluminescence (PL), ranging from 579 to 684 nm, was readily obtained by choosing the appropriate molecular weight sample of a mother polymer. This may provide a new method for evaluating organic luminescent materials. (author abst.)

Sodium azide is being applied not only in air bag inflators but also in organic syntheses producing azide ions containing process waste waters, mostly in alkaline aqueous solutions. The elimination of azide ions was attained in these process waste waters with hydrogenation under pressure with skeletal type nickel catalyst. The azide instantaneously reacts with the hydrogen content of the Raney-nickel. In sufficient amount it can even completely deactivate the catalyst.

Cu2O flower/grass-like nanoarchitectures (FGLNAs) were fabricated directly on two category specimens of Cu foils and Cu film using thermal oxidation method. The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width. The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs. The effects of surface conditions, such as the surface stresses, grain size, and surface roughness of Cu foil and Cu film specimens, on the FGLNA growth were discussed in detail. PACS 81. Materials science; 81.07.-b Nanoscale materials and structures: fabrication and characterization; 81.16.Hc Catalytic methods

Four kinds of rare earth oxides, lanthana, ceria, praseodymia and neodymia were separately added as promoters to nickel catalyst (Ni/γ-Al2O3). The nickel catalysts formed, NRL, NRC, NRP, NRN, have a typical structure of mezzanine that is unfit for carbon deposition on nickel catalyst. Ni−Nd/γ-Al2O3 shows higher selectivity for carbon-free operation.

The hydrogenation of 4-(2-furyl)-2-oxobutenoic acid sodium salt on a nickel catalyst has been studied. Using Raney nickel catalyst, the corresponding salts of 4-(2-furyl)-2-oxobutanoic acid, 4-(2-furtyl)-2-hydroxybutanoic acid, and aliphatic hydrogenolysis products of the initial compound were obtained. The sodium salt of 2-hydroxy-4-(2-tetrahydrofuryl) butanoic acid and the condensation product 4-(2-furylethyl)-3-(2-furylmethyl)-2-oxo-3,4-didehydroglutaric acid were detected in the hydrogenolysate. A method has been developed for obtaining the sodium salts of 4-(2-furyl)-2-oxobutanoic and 4-(2-furyl)-2-hydroxybutanoic acids.

Experimental data obtained in a Parr reactor for vegetable oil hydrogenation rate using a nickel catalyst supported on clay, with different catalyst to oil ratios and different stirring speeds are used to show the regime of operation and to calculate the contribution of resistance to external hydrogen diffusion to the process rate.

Hydrogenation of alkynes from decyne and dodecyne (C10-C12) with the triple bond at C3, C4, C5, and C6 led to the corresponding alkenes on a boron-nickel catalyst modified by 1-phenyl-2,3-dimethyl-4-amino-5-pyrazolone (4-aminoanti-pyrene). The stereospecificity for formation of the cis-alkenes was 95–98%.

Catalytic hydroamination of 1,2-bis-(hydroxymethyl)cyclohexane by aliphatic nitriles over a nickel catalyst yielded a series of N-alkyl-substituted octahydroisoindoles. Conditions for their synthesis were selected. The IR, PMR, and mass spectra and the probable mechanism of formation of these compounds are discussed.

3,5,7-Tribromo-1-azaadamantane is made by the action of sodium nitrite on 3,5,7-triamino-1-azaadamantane in concentrated hydrobromic acid. The reduction of this compound with hydrazine hydrate in the presence of a nickel catalyst gives 1-azaadamantane.

The chemisorption of hydrogen on Ni/SiO2 has been studied by measuring temperature programmed desorption on various samples under various experimental conditions. Two peaks are found, which can be related to a weakly and to a strongly bound species of chemisorbed hydrogen. Their analysis has been performed by a method which makes possible to determine whether a certain kinetic model can describe the entire desorption process or to assign a clear meaning to the corresponding kinetic parameters.

The catalyzed asymmetric synthesis of R-lysine S-α-phenylethylamide has been carried out by the diastereoselective hydrogenation of 5-cyano-2-hydroxyiminovaleric acid S-α-phenylethylamide over a skeletal nickel catalyst in a solvent containing α-phenylethylamine, at raised pressures. The excess of the RS-diastereoisomer was 6–12%.

The possible routes of toluene formation in the hydrogenolysis of n-hexane on nickel catalyst have been investigated by a tracer technique. The direct alkylation process seems to occur and toluene formation via disproportionation may be excluded.

A method of analysis has been developed by HPLC to monitor the progress of the electrosynthesis of aryl-2 propionic acids. This method elucidates the role of the nickel catalyst.

1. Hydrogenation of the acetylacetonates of Ni, Co, Cu, and Zn at atmospheric pressure and at 100 atm both on Ni and on NiM proceeded at a lower rate than the hydrogenation of pure acetylacetone. The rate of hydrogenation grew along the series of acetylacetonates Co < Zn ≤ Ni < Cu (Ni) and Co < Zn ≤ Cu < Ni (NiM). 2. Hydrogenation of acetylacetonates on a nickel catalyst modified with (+)-tartaric acid led to the formation of optically active products.

The synthesis of 2, 7-diamino-5,10-dioxo-4,5,9,10-tetrahydro-4,9-diazapyrene (Ia) and its 4,9-dihydroxy derivative (IIa) from diphenic acid (III) is described. 4,4′,6,6′-Tetranitrodiphenic acid (IV) was obtained by nitration of III. Reduction of IV with iron or with hydrogen over Raney nickel gave Ia, while reduction with stannous chloride gave IIa. Diacetyl and tetraacetyl derivatives of Ia and IIa were obtained. The amino groups in Ia and IIa were replaced by H, Cl, Br, I, CN, N02, and OH through diazotization. It is shown that II and its derivatives can be reduced with iron or with hydrogen over a nickel catalyst to compounds of the 5,10-dioxo-4,5,9, 10-tetrahydro-4,9-diazapyrene series.

The present paper describes a method for experimental determination of the momentary values of the thermal analyser calorimetric sensitivity when the type of gas in the DTA cell is changed.

1. A study was carried out on the hydrogermylation of 1,3-dienes by triethylgermane using nickel catalyst systems. The reaction of substituted 1,3-dienes and triethylgermane proceeds selectively by 1,4-cis-addition. The hydrogermylation of butadiene is accompanied by the formation of a series of octadienyl derivatives. 2. The optimal conditions were found for the preparation of HGeEt3 by the reduction of Et3GeI.

N,S-Divinyl-2-mercapto benzimidazole was obtained by reaction of 2-mercaptodimidazole with acetylene under pressure in the presence of heavy metal salts. N-Vinyl-S-ethyl-2-mercaptobenzimidazole was synthesized by hydrogenization of the product on a nickel catalyst. A high-melting polymer is obtained from N,S-divinyl-2-mercaptobenzimidazole under free-radical conditions.

The corresponding mono-, di-, and triamino derivatives substituted in the 2, 4, and 8 positions of the phenanthridone ring were obtained by reduction of mono-, di-, and trinitro-substituted phenanthridone (I), phenanthridone-10-carboxylic acid (II), phenanthridone-1-carboxylic acid (III), 4H-cyclopenta[k,l,m]phenanthridine-5,9-dione (IV), 4H-cyclopenta[k,l,m]phenanthridin-5-one (V), 5,10-dioxo-4,5,9,10-tetrahydro-4,9-diazapyrene (VI), and 5,9-dioxo-4,5,9,10-tetrahydro-4,10-diazapyrene (VII) with powdered iron in an electrolyte medium, with hydrogen in the presence of a nickel catalyst, or with stannous chloride. The 2,4,7,9-tetraamino derivative of VI was similarly obtained. 1-Amino-, 7-amino-, and 10-amino-phenanthridones were obtained by the Schmidt reaction from the corresponding carboxylic acids. 1,10-Diamino-, and 3,8-diaminophenanthridones were similarly obtained from the corresponding aminofluorenones.

1. A study was made of the effect of pressure, temperature and the nature of the solvent on the hydrogenation of furfurylideneacetone. 2. The hydrogenation proceeds in two directions: via the formation of 1-(α-tetrahydrofuryl)-3-butanone and 1-(α-furyl)-3-butanol, in which connection the first is the predominant direction. The obtained results are in agreement with the conclusions made on the basis of the energy concepts of the multiplet theory of catalysis.

Calculations were made of the energy of the bond formed by carbon with the surface of a nickel catalyst on the assumtion that the excess of free energy of the surface compounds is determined mainly by the excess of free energy of the surface of the catalyst.

1. A chemical method for the removal of hydrogen from a skeletal nickel catalyst is described; it serves at the same time as a method for the determination of the amount of chemically active hydrogen contained in the metal. 2. The method makes it possible to establish a relationship between the activity of a skeletal catalyst and its hydrogen content. 3. The effect of the amount of catalyst, the amplitude of the shake, and the dimensions of the flask on the reaction rate is also investigated.

1. The comparative hydrogenation of tetrahydrodioxo(dihydroanthrylene)triptycene (I) in dioxane and dimethylformamide was investigated on Ni, 1% Pd/C, and 10% Pd/C catalysts. 2. The adduct (I) is hydrogenated on a nickel catalyst at a lower rate than diethyl maleate, but at a higher rate on Pd/C catalysts. 3. Hydrogenation of the adduct (I) on a Ni catalyst is hindered in comparison with diethyl maleate in dioxane medium and proceeds at a somewhat greater rate in dimethylformamide. 4. From the experimental data it follows that a Ni catalyst possesses greater nonuniformity of the catalytic surface in comparison with Pd/C catalysts.

1. In binary mixtures of normal α-acetylenic hydrocarbons (C5-C7), β-acetylenic hydrocarbons (C5-C6), and of β- and γ-acetylenic hydrocarbons (C5-C6), over a skeletal nickel catalyst the components of the mixture are hydrogenated simultaneously at identical rates. 2. In the first stage of the hydrogenation of binary mixtures of α- and β- and of α- and γ-acetylenic hydrocarbons, the α-acetylenic hydrocarbons are hydrogenated preferentially. 3. The C5-C7 acetylenic hydrocarbons studied and the olefins formed from them are hydrogenated in the following order, characterizing their relative adsorbabilities by a nickel catalyst: α-acetylenic hydrocarbons, β- and γ-acetylenic hydrocarbons, α-olefins, β- and γ-olefins.

1. An investigation was made of the reaction of cycloheptanone with ammonia and hydrogen in presence of nickel on active alumina at 190–290°. 2. It has shown that, under these conditions, the seven- membered ring contracts to a six- membered ring with formation of cyclohexanemethylamine.

Kaolin and kyanite-sillimanite refractories during heating in hydrogen up to 1500°C sinter intensely, as a result of which there is a sharp reduction in the porosity, and an alteration in other properties. All the tested aluminosilicate refractories containing 42–62% alumina when heated up to 1500°C in hydrogen rapidly lose their weight as a result of the reduction of the SiO2, changing the structure of the surface layer, which is an active part of the catalyst carrier. These refractories cannot be recommended as carriers operating at high temperatures. The high-alumina refractories containing 79 and 90% Al2O3 have a much lower loss in weight, and during heating slightly change their porosity and other properties; they can be used as carriers for nickel catalysts.

1. An investigation has been made of the thermal deactivation of a skeletal nickel catalyst in a current of nitrogen and in a vacuum. 2. It has been shown that a skeletal nickel catalyst is of good stability, to baking in a current of nitrogen in absence of organic substances. Its activity is not reduced by a two-hour baking at 300%; deactivation and dehydrogenation of the catalyst become appreciable only at 400° and higher, and they then become more and more marked as the temperature is raised. 3. When the catalyst is heated in a vacuum, its activity falls more rapidly than when treatment is carried out in a current of nitrogen. 4. The results obtained support our hypothesis that the most important cause of the loss in the activity of skeletal nickel catalyst under the usual conditions of hydrogenation is not recrystallization, but destruction of the active surface by chemical dehydrogenation and blocking.

Heterogeneous catalysts are differentiated with respect to sulphur poisoning, viz. sulphur sensitive, e.g. Ni, and sulphur immune, e.g. MoS2. Immunity to poisoning is related to temperature, and inversely to catalyst activity. It is stated that nickel catalyst for the selective hydrogenation of cottonseed and like oils should be pure and preferably derived from an unusually active and readily reducible compound of nickel. Three sources of impurities, and the possible relation to promoters of one source in particular, are described. Catalysts are differentiated with respect to the form of the support, viz. bowder, impregnate, superficial. The superficial catalyst in stationary form appears best adapted for continuous hydrogenating equipment in the industry.

1. An investigation was made into the deactivating effect of steam on nickel catalysts in the course of their preparation by reduction with hydrogen under pressure. 2. It was shown that pretreatment of a mixture of nickelous oxide and carrier (Al2O3, MgO) with steam under pressure results in the formation of catalysts of low activity. Similar treatment of a reduced carriersupported nickel catalyst has a very much smaller effect on activity. 3. It was shown that steam treatment of a coprecipitated mixture of nickelous oxide and alumina ( or magnesia) under pressure results in a far-reaching irreversible change, namely recrystallization with great reduction in specific surface. 4. It is evident that the deactivation of reduced nickel catalysts by steam in the course of their use is due to the formation of nickelous oxide films or phases that rapidly recrystallize and are reduced with difficulty with formation of coarsely dispersed nickel. It is probable that the mechanism here proposed is applicable also to the deactivation of iron catalysts by water vapor.

1. A study was made of the sequence and stereochemistry of processes in the hydrogenation of (+)-p-mentha-6,8-dien-2-one over Raney nickel in ethanol at 20°. 2. Procedure for the Chromatographic analysis of the reaction products was worked out. 3. The hydrogenation of p-mentha-6,8-dien-2-one goes through the intermediate formation of p-menth-8-en-2-one, iso-p-menth-8-en-2-one, and p-menth-6-en-2-one, which are then hydrogenated to isomeric p-menthan-2-ones, and these further to four isomeric p-menthan-2-ols. 4. The pH of the medium affects not only the rate of the process, but also the selectivity and the course of the process; in an alkaline medium the hydrogenation of p-mentha-6,8-dien-2-one goes selectively through the formation of intermediate p-menth-8-en-2-one and iso-p-menth-8-en-2-one.

1. An attempt was made to estimate quantitatively the significance of the two sources of selectivity and stereospecificity in the general selectivity of the process of hydrogenation of n-pentynes on Pd, Pt, Rh, and Raney nickel catalysts. 2. The selectivity and stereospecificity of the processes of hydrogenation of n-pentynes with respect to the formation of monoolefins of the expected strucutre, due to adsorption displacement and the mechanism of hydrogenation before desorption of the products formed from the surface of the catalyst were tentatively calculated.

1. A study has been made of the activity of skeletal iron catalyst in hydrogenation reactions. 2. It has been established that this catalyst has a considerable activity in hydrogenation reactions at 20° and normal pressure. 3. The activity of an iron catalyst for the hydrogenation of an ethylene bond is two to three times less than that of a skeletal nickel catalyst. 4. Compounds containing a triple bond are hydrogenated at a somewhat lower rate than compounds containing an ethylene bond. A carbonyl group is hydrogenated still more slowly.

1. The principles pertaining to the sequence of reactions in the hydrogenation of compounds of the furan series over a nickel catalyst, derived earlier on the basis of the multiplet theory, find further confirmation in a large number of cases (52 conversions). 2. This principle proved to be correct practically without exception below 150°. Above this temperature complications are encountered, the causes of which are discussed.