Hydrogenation Of Aromatic Hydrocarbons Research Articles

Optimum Conditions for Simultaneous Reactions of Hydrogenation of Aromatic Hydrocarbons and Isomerization in Diesel Fuel Dewaxing Process

Optimum Conditions for Simultaneous Reactions of Hydrogenation of Aromatic Hydrocarbons and Isomerization in Diesel Fuel Dewaxing Process

Biocarbon Supported Nanoscale Ruthenium Oxide-Based Catalyst for Clean Hydrogenation of Arenes and Heteroarenes

Despite considerable achievements in the hydrogenation of aromatic hydrocarbons over the last few years, the ability to hydrogenate arene or heteroarene rings in a highly selective manner in the pr...

Catalytic activity of in situ synthesized MoWNi sulfides in hydrogenation of aromatic hydrocarbons

MoWNi–sulfide catalysts were obtained in situ by thermal decomposition of metal–polymer precursors based on the copolymers of polymaleic anhydride in a hydrocarbon raw material. The activity of the synthesized catalysts in hydrogenation of bicyclic aromatic hydrocarbons was studied, and the composition and structure of active phase nanoparticles were determined.

Synthesis of Ni–W aromatic hydrocarbon hydrogenation catalysts by the ex situ and in situ decomposition of a precursor based on a dendrimer network

A Ni–W precursor supported on a dendrimer-containing crosslinked polymer (42 wt % of a third-generation polypropylenimine dendrimer) has been first synthesized. The precursor has been subjected to the ex situ and in situ decomposition in a hydrocarbon feedstock to prepare an unsupported Ni–W sulfide catalyst. The activity of the resulting catalyst in the hydrogenation of aromatic hydrocarbons has been studied using the example of naphthalene. The process has been conducted in an autoclave-type reactor in a temperature range of 350–400°C at a hydrogen pressure of 5.0 MPa. It has been shown that the in situ synthesis of a Ni–W catalyst leads to the formation of particles exhibiting higher activity in the hydrogenation of naphthalene. The in situ synthesized Ni–W particles have been characterized by TEM and XPS.

Preparation of Ni—W aromatic hydrocarbon hydrogenation catalysts by breaking reverse emulsions or suspensions of a precursor in hydrocarbon feedstock

Reverse emulsions (hydrocarbon feedstock)/(aqueous precursor solution) for synthesizing aromatic hydrocarbon hydrogenation catalysts have been prepared using the water-soluble salts (NH4)2WS4 and Ni(NO3)2 · 6 H2O as precursors. It has been found that the optimum stabilizer for the emulsions is the nonionic surfactant SPAN-80. The resulting emulsions exhibit low catalytic activity in the hydrogenation of aromatic hydrocarbons; it has been shown that the activity of the systems in hydrodearomatization reactions is adversely affected by the presence of water. A procedure for preparing suspensions of solid precursor particles in a hydrocarbon feedstock by the removal of water from the resulting reverse emulsions has been developed. The catalytic activity of the resulting suspensions in the hydrogenation of aromatic hydrocarbons has been studied using naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene as examples. It has been shown that the catalytic activity of the suspensions is higher than that of the reverse emulsions of the same composition. It has been found that the feedstock should be subjected to additional sulfurization with elemental sulfur for further sulfiding the surface of the nickel—tungsten catalyst. The W: Ni molar ratio of 1 : 1 has been found to be optimum.

Catalysts for selective hydrogenation of aromatic nitrocompounds and hydrocarbons

The liquid-phase hydrogenation of nitrocompounds and aromatic hydrocarbons at the elevated pressure of hydrogen on the mono- and bimetallic supported catalysts was studied. The optimumtechnological parameters of reactions for obtaining a high yield of target products were determined. It was shown that the mechanism of transforming aromatic nitro compounds – hydrogenation and it was identical for all solvents. It was studied the influence of the added hydrogenation reaction product (p-aminophenol) during p-nitrophenol hydrogenation for determination the cause of reducing of velocity of hydrogenation. It was revealed that the monometallic Rh/Al2O3 or bimetallic catalysts of Rh-Pt/Al2O3 composite are the most active catalysts for hydrogenation of aromatic hydrocarbons. The catalysts applied on aluminum oxide are more active and selective, than the catalysts applied on a silica gel.

Hydrogenation of aromatic hydrocarbons in a mixture with thiophene on sulfided Pd/Al2O3 catalysts

The activity and stability of aluminum-palladium catalysts in the hydrogenation of aromatic hydrocarbons mixed with thiophene were studied. The catalysts were obtained by impregnation of γ-A2O3 with aqueous solutions of salts of palladium complexes. Preliminary sulfiding followed by oxidative activation of Pd/Al2O3 catalysts were found to favor the formation of such palladium state on the surface at which the hydrogenation of aromatic hydrocarbons in the presence of sulfur-containing impurities proceeds without a noticeable change in the activity with time. IR spectroscopy showed that the palladium metal surface fragments forming CO complexes with a characteristic absorption band at 1998 cm–1 are resistant to poisoning with sulfur-containing compounds in the hydrogenation of aromatic hydrocarbons.

Synthesis and Study of Ni-Mo-Co Catalysts for Hydroprocessing of Oil Fractions

AbstractThe problems of synthesis of Ni-Mo, Ni-Mo Co and Co-Mo oxide catalysts for hydrodesulfurization and hydrogenation of aromatic hydrocarbons in the composition of kerosene, diesel and oil fractions are discussed. The influence of spent adsorbent and kaolin as the additives on the physical-chemical and catalytic properties of bimetallic and trimetallic catalysts is established.

Hydrogenation of aromatic hydrocarbons in the presence of dibenzothiophene over platinum-palladium catalysts based on Al-SBA-15 aluminosilicates

The hydrogenation of a 2-methylnaphthalene solution in n-heptane in the presence of dibenzothiophene (400 ppm in terms of sulfur) over Pt-Pd catalysts containing Al-SBA-15 mesoporous aluminosilicates has been studied. Supports for the catalysts contained 35 wt % Al-SBA-15 and 65 wt % γ-Al2O3. The Pt and Pd contents of the catalysts was 0.25 and 1.0 wt %, respectively. Experiments with the model feedstock were conducted in an autoclave at 240–260°C, an initial hydrogen pressure of 30 atm, and a substrate/metal weight ratio of 30. It has been found that a catalyst based on Al-SBA-15 with Si/Al = 5 exhibits the highest activity under poisoning with 400 ppm sulfur. Thus, the conversion of 2-methylnaphthalene at 260°C after 3 h was 85% with the selectivity for methyltetralins of 97%. The dearomatization of a hydrotreated diesel fraction with 45 ppm sulfur at 260°C at a pressure of 30 atm and a space velocity of 2.4 h−1 has made it possible to decrease the total aromatic content, in particular reduce the concentration of polycyclic aromatic compounds to a level of less than 1 wt %.

ChemInform Abstract: Homogeneous Catalytic Hydrogenation of Aromatic Hydrocarbons and Heteroaromatic Nitrogen Compounds: Synthetic and Mechanistic Aspects

The synthetic and mechanistic aspects of the homogeneous catalytic hydrogenation of mono and polynuclear aromatic hydrocarbons and the corresponding heteroaromatic nitrogen compounds will be reviewed. A comparison of the regioselectivities under various hydrogenation conditions for both classes of compounds will be discussed for a wide variety of transition-metal complexes with regard to substrate binding at the metal center and the role of free radical intermediates in metal carbonyl hydride reactions, where substrate does not bind to the metal center prior to hydrogen transfer. The polynuclear heteroaromatic nitrogen compounds appear to hydrogenate more readily, under similar reaction conditions, than the polynuclear aromatic hydrocarbons. The relative rates of hydrogenation of a variety of heteroaromatic nitrogen compounds as well as compounds that inhibit and enhance selective hydrogenation of the nitrogen-containing ring will be addressed. A relatively new spectroscopic technique, high pressure nuclear magnetic resonance spectroscopy, will be shown to be a powerful tool to elucidate the mechanisms of the regioselective hydrogenation of polynuclear heteroaromatic nitrogen compounds.

ChemInform Abstract: Hydrogenation of Aromatic Hydrocarbons Over Supported Pt Catalysts. Part 3. Reaction Models for Metal Surfaces and Acidic Sites on Oxide Supports

ChemInform Abstract: Hydrogenation of Aromatic Hydrocarbons Over Supported Pt Catalysts. Part 3. Reaction Models for Metal Surfaces and Acidic Sites on Oxide Supports

ChemInform Abstract: Hydrogenation of Aromatic Hydrocarbons Over Supported Pt Catalysts. Part 1. Benzene Hydrogenation.

ChemInform Abstract: Hydrogenation of Aromatic Hydrocarbons Over Supported Pt Catalysts. Part 1. Benzene Hydrogenation.

Influence of trace oxygen on the hydrogenation activity of Ru/Al2O3 catalysts

The influence of trace oxygen on the catalytic activity of alumina supported Ru in the liquid phase hydrogenation of aromatic hydrocarbons was studied. The catalytic activity of Ru increased remarkably and the reproducibility was improved by removing dissolved oxygen from the reactant mixture and carefully refining the catalyst transfer procedure into the reactor to avoid exposure to air. Trace oxygen affected Ru very severely, but did not affect Rh, Pd, and Pt much. The activity of Ru was lower than those of Rh, Pd, and Pt in the presence of oxygen as reported in the literature; however, it was the highest when oxygen was removed carefully. Measurements of the adsorbed oxygen suggested that the activity seriously decreased when only the part of Ru surface was covered by oxygen. Bimetallic Pt–Ru catalysts demonstrated high activity even in the presence of oxygen.

Hydrogenation of aromatic hydrocarbons on nickel catalysts modified with heteropolycompounds

Summary 1. The high activity and selectivity of nickel catalysts (1–4 wt.%) was established on γ -Al 2 O 3 modified with heteropolytungstates for hydrogenation of benzene and toluene. 2. High-temperature treatment at 500°–600°C was shown to be necessary for forming active and stable catalysts for hydrogenation. 3. Systems modified with heteropolytungstates containing Co and Ni were found to be the most active catalysts for benzene hydrogenation.

Kinetic Models Study of Hydrogenation of Aromatic Hydrocarbons in Vacuum Gas Oil and Basrah Crude Oil Reaction

The aim of this research is to study the kinetic reaction models for catalytic hydrogenation of aromatic content for Basrah crude oil (BCO) and vacuum gas oil (VGO) derived from Kirkuk crude oil which has the boiling point rang of (611-833)K. This work is performed using a hydrodesulphurization (HDS) pilot plant unit located in AL-Basil Company. A commercial (HDS) catalyst cobalt-molybdenum (Co- Mo) supported in alumina (γ-Al2O3) is used in this work. The feed is supplied by North Refinery Company in Baiji. The reaction temperatures range is (600-675) K over liquid hourly space velocity (LHSV) range of (0.7-2)hr-1 and hydrogen pressure is 3 MPa with H2/oil ratio of 300 H / l 2 of Basrah Crude oil (BCO), while the corresponding conditions for vacuum gas oil (VGO) are (583-643) K, (1.5-3.75) hr-1, 3.5 MPa and 250 H / l 2 respectively . The results showed that the reaction kinetics is of second order for both types of feed. Activation energies are found to be 30.396, 38.479 kJ/mole for Basrah Crude Oil (BCO) and Vacuum Gas Oil (VGO) respectively.

Effects of Removing Residual Chlorine on the Hydrogenation of Aromatic Hydrocarbons over Supported Ru Catalysts

Abstract Hydrogenation activity of aromatic hydrocarbons was remarkably increased when the residual chlorine on Ru/Al2O3 and Ru/SiO2 was removed by washing. On the basis of FT-IR spectra in the CO region, a site active for hydrogenation reactions was created by removal of the residual chlorine.

Investigation of Hydrogenation of Aromatic Hydrocarbons on Pt/Pd/USY Catalyst

In this paper the aromatic reduction of gas oils and the conversion of several hydrocarbon groups in the conditions of hydrodearomatization were investigated on Pt/Pd/USY catalyst. It was concluded that in case of hydrodearomatization of gas oils cycloparaffin hydrocarbons (naphthenes) were key components, i.e. the practical process parameters of hydrodearomatization in case of a defined catalytic system (catalyst, feed, etc.) is that where the concentration of naphthenes have a maximum value. In case of this the deep hydrodearomatization and further deep heteroatom reduction can be carried out with maximum yield of gas oil. It was additionally determined that in the condition of hydrodearomatization mainly isoparaffins are formed via ring opening of naphthenes, the rate of increase of n-paraffin concentration is slower, i.e. the decadence of cold flow properties of reduced aromatic containing products are less beside the high cetane number. Therefore the gas oil products can be applied as winter quality diesel fuel blending components.

Hydrofining of oil fractions of naphtheno-aromatic crude

The change of the chemical-group composition of oil fractions of naphtheno-aromatic crude during hydrofining was studied. A modified alumino-nickel-molybdenum catalyst for the hydrotreating (hydrofining) of oil fractions is proposed. The high activity of the catalyst in the reactions of the hydrodesulfurization and hydrogenation of aromatic hydrocarbons and resins in the test process is demonstrated. Deep hydrogenation of polycyclic aromatic compounds and resins results in a considerable increase in the viscosity index of the oil fractions. The conditions of the hydrofining of wide fractions were chosen, and appropriate amounts of the samples for the subsequent hydrogenation in the presence of the catalyst based on noble metals were produced. The hydrofining of oil fractions at the first stage makes it possible to run the second stage of the process (hydrogenation) on a catalyst that is sensitive to the poisonous effect of sulfur.

A Catalyst for Hydrogenation of Middle Distillates

A catalyst is proposed for hydrogenation of middle distillates. The results of testing it are reported. It is shown that this catalyst is more resistant to sulfur–containing compounds and ensures hydrogenation of aromatic hydrocarbons in mild conditions. In contrast to existing industrial catalysts that contain nickel, chromium, etc., as hydrogenating components, hydrogenation can be conducted on the proposed catalyst without preliminary hydrotreating.

The Development and Use of New Hydrogenation Catalysts1

Advantages and drawbacks of commercial catalysts for gas-phase hydrogenation are considered. The use of modified catalysts, including nickel catalysts modified with heteropoly compounds, is promising. Data on the selective reduction of carbonyl compounds and hydrogenation of aromatic hydrocarbons over these catalysts are presented. Palladium films are shown to be the best catalysts for the selective reduction of acetylene compounds to olefins.