Solvent hydrogenation of cottonseed oil

Refined and bleached cottonseed oil was dissolved in a solvent (hexane, isopropyl alcohol, or di-isopropyl ether) and was then hydrogenated in a dead-end hydrogenator. Hydrogenation runs were conducted at temperatures from 115 to 145°C., at hydrogen partial pressures from 44 to 74 p.s.i.a., with catalyst concentrations varying from 0.05 to 0.40% nickel, and at high rates of agitation to climinate mass-transfer resistances. A series of hydrogenation runs was also made in which no solvent was used. The rates of hydrogenation for the various series of runs were in the same order of magnitude but decreased in the following order: nonsolvent, hexane, isopropyl alcohol, and di-isopropyl other runs. Selectivity and isomerization were low in all cases and essentially identical for solvent and nonsolvent runs. The rate of hydrogenation increased in all cases with higher catalyst concentrations. For the isopropanol runs, the reaction rate was maximum as a function of temperature at about 135°C. In the case of the other solvents, the rate of hydrogenation increased with increased temperature in the range from 115 to 145°C., but the rate increases of the solvent runs were less than those of the nonsolvent runs.     

Highly uniform Ni particles with phosphorus and adjacent defects catalyze 1,5-dinitronaphthalene hydrogenation with excellent catalytic performance

This work proposes a modified activated carbon support, with defects and heteroatoms (N,P-ACs) by nitrogen and phosphorus doping to load non-noble nickel to catalyze aromatic compound hydrogenation. The Ni/N,P-ACs-900 (prepared at 900 °C) showed promising catalytic activity in liquid-phase 1,5-dinitronaphthalene hydrogenation with a 1,5-diaminonaphthalene yield of 95.8% under the mild condition of 100 °C, which is comparable to the commercial Pd/C catalyst. The nitrogen species were burned off at 900 °C, causing more defects for nickel metal loading, facilitating the interaction between the supports and the nickel metal, and resulting in highly dispersed metal particles. The computational study of the nickel binding energy has been conducted using density functional theory. It exhibits that the defects formed by heteroatom doping are beneficial to nickel anchoring and deposition to form highly uniform nickel particles. The phosphorus species in combination with the defects are suitable for H₂ adsorption and dissociation. These results reveal that the heteroatomic doping on the active carbon shows significant effects in the hydrogenation of the liquid-phase aromatic compounds. These findings could provide a promising route for the rational design of aromatic compound hydrogenation catalysts to significantly decrease the cost by instead using noble metal catalysts in the industry.     

Coal liquefaction by the hydrogen produced from methanol: 2. Model compound studies

Coal can be converted into a material soluble in solvents using methanol as an in-situ hydrogen source and also as an alkylating agent. This paper presents the results of the reaction of selected model compounds with methanol using two different hydrogenation catalysts: stabilized nickel at 365 °C, and stabilized cobalt at 405 °C and 445 °C. Stabilized nickel is a much better hydrogenation catalyst than stabilized cobalt. The alkylation reaction is strongly dependent on the presence of specific functional groups (-OH, -NH, etc). Also, the alkylation reaction appears to be independent of the hydrogenation catalyst used and it seems to depend more on the temperature. The alkylated products from the reactions at 405 °C showed an order as follows: carbazole phenol ? phenanthrene dibenzofuran diphenylether dibenzothiophene diphenylmethane. A free radical mechanism is proposed for the alkylation reaction.     

Formation and gasification of carbon deposits on NiSiO2 catalysts

The deposition of carbon from CH₄ and CO on $\text{Ni}\text{SiO}{}_2$ catalysts was studied in pulse-flow experiments as well as volumetrically with a low-field magnetic permeameter. It was found that carbon, deposited from CH₄ according to: CH₄ → C + 4H, gave rise to the formation of nickel carbide, Ni₃C, only at the surface of the nickel particles (T< 300 °C). However, carbon, deposited from CO according to: 2CO → C + CO₂, led to the formation of a bulk nickel carbide as well as dissolution of carbon interstitially. The reactivity of the carbon thus deposited was studied with both H₂ and H₂O. The rate of reaction with hydrogen appeared to be a function of temperature: the rate passed through a maximum at 200 °C and dropped steeply above 300 °C. The only product of the reaction was CH₄. The reaction with H₂O produced besides CH₄, CO₂ and (at low carbon surface coverages) H₂.     

Coal liquefaction by the hydrogen produced from methanol

Methanol was used as an in-situ hydrogen source, following its decomposition over ZnO-Cr₂O₃, for the hydrogenation of coal. The reaction was carried out in a high pressure autoclave at ≈400–440 °C, in the presence of different hydrogenation catalysts. Stabilized nickel, stabilized Co and Ni-Cr-Cu catalysts gave excellent results. The maximum conversion was 100% for pyridine, 94.4% for benzene and 66.2% for straight-chain hexane.     

Hydrogenation of catalytic carbons obtained by CO disproportionation or CH4 decomposition on nickel

The hydrogenation of catalytic carbons has been studied in the temperature range of their deposition (300–700°C) by CO disproportionation or by CH₄ decomposition on nickel powders. When obtained under non carbiding conditions, the catalytic carbons are very reactive between 350 and 600°C where uncatalysed carbons are inert. The reactivity does not depend on the temperature of deposition and on preliminary heat treatment, but depends on the degree of gasification. This reactivity is imputed to the quality of the metal carbon interface which allows a good deposition-gasification reversibility. When deposition occurs under carbiding conditions, both deposition and subsequent hydrogenation are poisoned by the carbon formed by thermal decomposition of the carbide.     

The hydrogenation of triglycerides using supported alloy catalysts. I. Silica-supported Ni—Ag catalysts

Silica-supported Ni-Ag catalysts with a loading of 2·1·0.6% (w/w) total metal have been prepared using the precursors nickel dimethylglyoxime and silver nitrate by means of a simple impregnation method. The resulting catalysts were activated by calcination at 260°C in air, followed by hydrogen reduction at 450°C. They were then employed for soyabean oil hydrogenation at 1 bar H2 pressure and 160°C in a stirred batch reactor. Characterisation of the catalysts using temperature-programmed reduction and electron microscopy indicated that alloying of nickel and silver had occurred, but metal particle composition, for a given overall composition, varied with metal particle size and smaller metal particles were nickel rich. The hydrogenation activity and selectivity measurements revealed that the catalysts were more active and selective than a commercial nickel catalyst. Furthermore, the specific activities of the alloy catalysts were a maximum for alloys in the range 70–90 at. % Ni. However, the supported alloy catalysts also gave rise to greater trans isomerisation than the commercial catalyst. This is attributed to hydrogen deficiency caused by large triglyceride molecules blocking hydrogen chemisorption on small nickel particles (10–50 Å in diameter), leading to enhanced cis-trans isomerisation.     

Synergetic effect of molybdenum dioxide on nickel in the catalytic hydrogenation of benzene

Molybdenum dioxide is deposited on the form of an aerogel (in the autoclave) on nickel Mond. The catalytic activity for the hydrogenation of benzene into cyclohexane at 100°C depends on the proportion of MoO₂ and on the temperature of a pretreatment in hydrogen. When this temperature is 440°C, the catalytic activity exceeds that of pure nickel Mond and exhibits a maximum for about 10% of MoO₂. This synergetic effect, which is an exemple of a strong metal-support interaction (SMSI), is explained by the incorporation into the surface of nickel Mond crystals of molybdenum produced by partial reduction of MoO₂, with the formation of an inter-metallic compound MoNi₄.     

Application of new 13C n.m.r. techniques to the study of products from catalytic hydrodeoxygenation of SRC-II liquids

A middle-heavy SRC-II distillate (b.p. 230–455 °C), containing 3.0 wt% of oxygen, has been studied by means of ¹³C n.m.r. at 75, 100 and 125 MHz. The magnetization refocussing techniques INEPT and J-resolved two-dimensional Fourier transform have been utilized to demonstrate methods by which resonance line multiplicities may be determined in complex liquid mixtures. Products derived from the above coal liquid by hydrodeoxygenation at temperatures from 200 to 370 °C, using sulphided Co—Mo and Ni-W catalysts, were also examined. The fraction of aromatic carbon in the hydrotreated liquids was found to correlate directly with their C/H atomic ratio and inversely with the hydrogen content. Comparison of O/C atomic ratios with f_a values for these liquids indicates that hydrogen uptake < 260 °C is associated primarily with hydrogenolytic oxygen removal without attendant ring hydrogenation, while at temperatures between 260 and 350 °C hydrodeoxygenation is accompanied by ring hydrogenation and dealkylation reactions.     

Synthesis of pitch materials from hydrogenation of anthracite

A Pennsylvania anthracite was ground, carefully dried and hydrotreated into materials with properties resembling those of pitches. The hydrotreatment was carried out using two hydrogen donors, 9,10-dihydroanthracene (DHA) and 1,2,3,4-tetrahydronaphthalene (THN), and two catalysts, molybdenum hexacarbonyl (Mo(CO)₆) and ammonium tetrathiomolybdate (ATTM). Due to the high reactivity at low temperatures, the degree of hydrogenation was probed in the temperature range 300, 350 and 400 °C. The optimum hydrogen donor, catalyst and hydrogenation temperature were 1,2,3,4-tetrahydronaphthalene, ammonium tetrathiomolybdate and 300 °C, respectively. This was reflected in an increase in the hydrogen-to-carbon atomic ratio (H/C) from 0.33 for the original anthracite to 0.42 for the pitch-like material from anthracite. Further, differential scanning calorimetry (DSC) showed that the anthracite-derived pitch material had a glass transition temperature (T_g) around 81.6 °C and softening point of 205.7 °C. This indicates that the softening behavior of the anthracite-derived pitch is similar to that of high-softening-point coal tar pitches. The anthracite-derived pitch material was evaluated by producing a small carbon body directly from the anthracite-derived pitch, and partial binding was observed.     

Phenylacetylene hydrogenation on Fe@C and Ni@C core–shell nanoparticles: About intrinsic activity of graphene-like carbon layer in H2 activation

Me@C nanocomposites were prepared by evaporation of overheated liquid drop of Me in the flow of inert gas containing a hydrocarbon. The resulting carbon-coated nickel and iron nanoparticles contain metal cores of about 5 nm in size that are wrapped in a few layers of graphene-like carbon. Experimental data and theoretical results give evidence of the ability of carbon coating in nanocomposites Fe@C and Ni@C to H₂ activation by dissociative adsorption due to the presence of space and structure defects and/or the presence of transition metal in subsurface layer. Since molecular hydrogen dissociation is the key step of hydrogenation reactions, both Ni@C and Fe@C provide high conversion of phenylacetylene (PA) (about 100%) during hydrogenation at the temperatures above 150 and 300 °C, respectively. Fe@C provides excellent styrene (ST) selectivity: 86% at 99% PA conversion at 300 °C. ST selectivity is moderate on Ni@C (about 60%) in the temperature range of 100–150 °С and low at higher temperatures.     

Multilayered graphene films prepared at moderate temperatures using energetic physical vapour deposition

Carbon films were energetically deposited onto copper and nickel foil using a filtered cathodic vacuum arc deposition system. Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and UV–visible spectroscopy showed that graphene films of uniform thickness with up to 10 layers can be deposited onto copper foil at moderate temperatures of 750 °C. The resulting films, which can be prepared at high deposition rates, were comparable to graphene films grown at 1050 °C using chemical vapour deposition (CVD). This difference in growth temperature is attributed to dynamic annealing which occurs as the film grows from the energetic carbon flux. In the case of nickel substrates, it was found that graphene films can also be prepared at moderate substrate temperatures. However much higher carbon doses were required, indicating that the growth mode differs between substrates as observed in CVD grown graphene. The films deposited onto nickel were also highly non uniform in thickness, indicating that the grain structure of the nickel substrate influenced the growth of graphene layers.     

Effect of Carbon Deposits on Carbon Monoxide Hydrogenation over Alumina-Supported Cobalt Catalyst

The carbon deposits on alumina-supported cobalt catalysts and their effects on carbon monoxide hydrogenation were investigated concomitantly. Carbon monoxide hydrogenation was performed in a differential reactor operating at atmospheric pressure, temperature of 250–350°C and a hydrogen: carbon monoxide ratio of 3. Temperature-programmed surface reaction of carbon deposits with hydrogen and Auger electron spectroscopy were employed to obtain a better understanding of the nature of the carbon deposits. With increasing deposition temperature, the amount of carbon deposit increased and the atomic surface carbon transformed morphologically into polymeric and graphitic carbon. Carbon deposits resulted in the reduction of activation energy from 28–32 to 17–18 kcal/mol (117–134 to 71–75 kJ/mol) as well as significantly decreasing activity. Hydrocarbon product distributions were not affected by carbon deposits, but the obvious shift in selectivity from paraffins to olefins was observed with increasing carbon deposits.     

Preliminary Study on Direct Operation of LT‐SOFCs Based on GDC Electrolyte Film With DME Fuel

Direct operation of anode‐supported cone‐shaped tubular low temperature solid oxide fuel cells (LT‐SOFCs) based on gadolinia‐doped ceria (GDC) electrolyte film with dimethyl ether (DME) fuel was preliminarily investigated in this study. The single cell exhibited maximum power densities of 500 and 350 mW cm^–2 at 600 °C using moist hydrogen and DME as fuel, respectively. A durability test of the single NiO‐GDC/GDC/LSCF‐GDC cell was performed at a constant current of 0.1 A directly fuelled with DME for about 200 min at 600 °C. The results indicate that the single cell coking easily directly operated in DME fuel. EDX result shows a clear evidence of carbon deposition in the anode. Further studies are needed to develop the novel anti‐carbon anode materials, relate the carbon deposition with anode microstructure and cell‐operating condition.     

Pressure and temperature effects on the hydrogenation of coal-derived asphaltene

Pressure and temperature effects on hydrogenation reactions were examined using coal-derived asphaltene at 390,420 and 450 °C, under 3 and 10 MPa of hydrogen partial pressure. Higher conversion was obtained at higher reaction temperatures. Benzene-insoluble material (Bl) was formed at higher temperatures especially at low hydrogen pressure, this Bl being one-third of the reaction product at 450 °C. From structural analysis of unreacted asphaltenes and product oils, at 390 °C, it was concluded that smaller molecular components convert to oil initially and the larger molecules remain as unreacted asphaltene. Under higher hydrogen pressure for all temperatures carbon aromaticity (f_a) and number of aromatic ring per structural unit (R_aus) in unreacted asphaltenes were lower than those under lower hydrogen pressure suggesting that hydrogenation of the aromatic nucleus was promoted by higher pressure. At lower hydrogen pressure, R_aus for asphaltenes at higher temperature is larger than that at lower temperature. This suggests that at lower hydrogen pressure, dehydrogenation or condensation reactions occur more easily. A large effect at higher hydrogen pressure was a reduction in the extent of condensation reactions. Higher reaction temperatures contribute to splitting of bridged linkages so reducing molecular size and degree of aromatization.     

Preparation and characterization of low overvoltage transition metal alloy electrocatalysts for hydrogen evolution in alkaline solutions

Transition metal electrocatalysts for hydrogen evolution were prepared by thermal decomposition of solutions containing nickel or cobalt and molybdenum, tungsten or vanadium on a metallic substrate and curing the oxide coated substrate under an atmosphere of hydrogen at elevated temperatures.The most active and stable hydrogen evolving cathode, based on a nickel and molybdenum combination, exhibited overvoltages of about 60 mV for over 11,000 h of continuous electrolysis in 30 w/o KOH at 500 mA cm^?2 and 70°C. The cathode was prepared by high temperature (ca. 400°C) treatment of a nickel substrate, coated with an aqueous solution containing nickel and molybdenum salts in the atomic ratio 60:40 followed by reduction of the resulting oxides at about 500°C in atmosphere of hydrogen.X-ray diffraction, and thermogravimetric and ESCA measurements, were employed to identify the active component of the nickel-molybdenum system responsible for its electrocatalytic activity. The results indicated that the electrocatalyst is a face centred cubic nickel-molybdenum alloy in which the molybdenum is randomly substituted at the nickel lattice.The electrochemical properties of a number of nickel-molybdenum electrocatalysts (NiMo = 60:40) were determined in the temperature range 20–80°C. Steady state measurements at different temperatures in 30 w/o KOH showed that the electrodes had low apparent activation energies (ca. 5 kcal mol^?1) and revealed the presence of two Tafel regions with transfer coefficients of 1.13 and 0.63. The corresponding exchange current densities at 70°C, based on the electrodes geometric areas, were 52 and 150 mA cm^?2 respectively. Results of potentiodynamic measurements and preliminary work on hydrogen oxidation are also presented.     

Activation studies with an iron fischer-tropsch catalyst in fixed bed and stirred tank slurry reactors

A precipitated iron catalyst (100 Fe/5 Cu/4.2 K/25 SiO₂ on a mass basis) was tested in a fixed bed reactor and a stirred tank slurry reactor under the same process conditions (250°C, 1.48 MPa, 2 L (STP)/gcat · h, H₂ : CO = 2:3). Two different pretreatment procedures were employed (hydrogen reduction at 220°C and carbon monoxide activation at 280°C) in each of the two reactor types. In the stirred tank slurry reactor tests the activity (based on an apparent first order reaction rate constant) of the carbon monoxide pretreated catalyst was about 25% higher than that of hydrogen reduced catalyst, due to incomplete reduction of the latter. In all tests the catalyst selectivity changed slowly with time on stream. Hydrocarbon distribution shifted toward lower molar mass products, and secondary reactions (l-olefin hydrogenation, isomerization and readsorption) increased with time. The secondary reactions were the most pronounced on the hydrogen reduced catalyst in the fixed bed reactor.     

Catalytic transfer hydrogenation of 7-ketolithocholic acid to ursodeoxycholic acid with Raney nickel

Ursodeoxycholic acid was produced by the stereoselective reduction of 7-ketolithocholic acid. This hydrogenation reaction was catalyzed by the T-1 Raney nickel and potassium borohydride was used as hydrogen donor instead of inflammable hydrogen gas. Potassium tert-butoxide was introduced to improve yield of ursodeoxycholic acid from about 70% to a maximum of 94% by inducing the stereoselectivity on hydroxyl group at 40 °C and atmospheric pressure. Reduction reaction conditions such as amount of reactants, temperature and stirring speed were optimized. The whole process is safe and low-cost. Eventually, the product, ursodeoxycholic acid was characterized by IR, ¹H NMR and ¹³C NMR spectra.     

Hydrodesulfurization of Dibenzothiophene and its Hydrogenated Intermediates Over Bulk Ni2P

A bulk Ni₂P catalyst was prepared by co-precipitation of nickel phosphate followed by in situ temperature-programmed reduction (TPR) with H₂. The hydrodesulfurization (HDS) of dibenzothiophene (DBT) and its hydrogenated intermediates 1,2,3,4-tetrahydro-dibenzothiophene (TH-DBT) and 1,2,3,4,4a,9b-hexahydro-dibenzothiophene (HH-DBT) was studied at 340 °C and 4 MPa both in the presence and absence of piperidine (Pi). Bulk Ni₂P exhibited a relatively low hydrogenation/dehydrogenation activity but high desulfurization activity. Pi retarded the hydrogenation of DBT to a greater extent than the desulfurization. The desulfurization of HH-DBT to 2-cyclohexen-1-yl-benzene (CHEB-2) occurred mainly by ??-elimination of the hydrogen atom attached to carbon atom C(4), whereas TH-DBT desulfurized mainly by hydrogenolysis to 1-cyclohexen-1-yl-benzene (CHEB-1). A minor amount of biphenyl (BP) observed in the HDS of TH-DBT and HH-DBT is due to the disproportionation of cyclohexenyl-benzenes. A reaction network of the HDS of DBT over Ni₂P is postulated in which both ??-elimination and hydrogenolysis play a role in the breaking of the C?CS bonds.     

Modification of vegetable oils. XI. The formation of trans isomers during the hydrogenation of methyl oleate and triolein

Summary 1. During the hydrogenation of methyl oleate, trans isomers are formed at a very rapid rate. As much as 38% of trans isomers formed while the first 10% of methyl stearte was formed. 2. The rate of formation of trans isomers in methyl oleate undergoing hydrogenation is increased by increasing the temperature, increasing the catalyst concentration, and decreasing the degree of dispersion of the hydrogen. 3. The hydrogenation of methyl oleate always resulted in the establishment of an equilibrium between cis and trans isomers, and irrespective of the conditions employed the concentration of trans isomers was always 67%, calculated on the basis of total unsaturated constituents. 4. It is concluded that all of the iso-oleic acids formed during the hydrogenation of methyl oleate adsorb hydrogen at the same rate as oleic acid and are adsorbed and desorbed from the nickel catalyst with equal ease. 5. Trans isomers are formed at a slightly lower rate during the hydrogenation of triolein than in the case of methyl oleate. 6. Partial hydrogenation of triolein also results in the establishment of an equilibrium between cis and trans isomers of oleic acid but at values of less than 67% of trans constituents (based on the total unsaturated constituents) observed with methyl oleate. The equilibrium concentration was found to vary with the conditions of hydrogenation and was found to be 62% at 200°C. and 57% at 175°C. Report of study made under the Research and Marketing Act of 1946. Presented at the 24th Fall Meeting of the American Oil Chemists’ Society, San Francisco, Calif., Sept. 26–28, 1950. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.