A. B. Kulikov

Synthesis of nickel–tungsten sulfide hydrodearomatization catalysts by the decomposition of oil-soluble precursors

Nickel–tungsten sulfide catalysts for the hydrogenation of aromatic hydrocarbons have been prepared by the in situ decomposition of an oil-soluble tungsten hexacarbonyl precursor in a hydrocarbon feedstock using oil-soluble nickel salt nickel(II) 2-ethylhexanoate as a source of nickel. The in situ synthesized Ni–W–S catalyst has been characterized by X-ray photoelectron spectroscopy. The activity of the resulting catalysts has been studied in the hydrogenation of bicyclic aromatic hydrocarbons and dibenzothiophene conversion in a batch reactor at a temperature of 350°C and a hydrogen pressure of 5.0 MPa. It has been shown that the optimum W : Ni molar ratio is 1 : 2. Using the example of the hydrofining of feedstock with high sulfur and aromatics contents, it has been shown that the synthesized catalyst exhibits high activity in the hydrogenation of aromatic hydrocarbons.

Hydrogenation of aromatic compounds in the presence of dibenzothiophene over bimetallic catalysts containing mesoporous aluminosilicates

The hydrogenation of a mixture of naphthalene, tetralin, and toluene (a solution in n-heptane) in the presence of dibenzothiophene (150 and 400 ppm on a sulfur basis) over Pt-Pd catalysts containing Al-HMS mesoporous aluminosilicates has been studied. The catalyst supports contained 35 wt % Al-HMS and 65 wt % γ-Al2O3. The Pt and Pd loadings in the catalysts were 0.2 and 0.8 wt %, respectively. The process was carried out at 200–240°C, a pressure of 30 atm, and a weight hourly space velocity of 1.7 h−1. It has been found that the catalyst based on Al-HMS with Si/Al = 10 exhibits the highest activity. Thus, in the hydrogenation of a model mixture containing 150 and 400 ppm of sulfur, the conversion of toluene at 240°C was 22.2 and 10.9 wt %, respectively. In the presence of this catalyst, the concentration of aromatic hydrocarbons in the hydrotreated diesel fraction decreased from 28.4 to 6.8 wt %, and the sulfur content decreased from 45 to 5 ppm.

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.

Conversion of C19–C38 n-paraffins into components of kerosene and diesel fuels on Pt-containing amorphous aluminosilicate

The behavior of Pt-containing catalysts based on mesoporous amorphous aluminosilicate in the process of hydroconversion of C19–C38n-paraffins with the goal to produce diesel and kerosene fractions with improved cold flow properties was investigated. These systems were characterized by high efficiency and selectivity in the process of producing diesel and kerosene fractions. A 91% degree of conversion was achieved with a yield of liquid hydrocarbons of 76% (320°C, volume feed rate 0.5 h–1, molar ratio hydrogen: feed = 600: 1, pressure 50 atm). The initial freezing point of the isolated kerosene fraction was below minus 50°C, and the cold filter plugging point of the diesel fraction was minus 34°C.

Lipids of Basidial Fungi as Feedstock for Biodiesel Fuel Production

The scientific literature on the influence of various factors on the lipid content and composition in biomass of basidial fungi was reviewed. The influence of carbon and nitrogen sources, C:N ratio, temperature, and pH of the medium on the biomass yield and lipid fatty-acid content and composition was analyzed for various basidial fungi. The most promising substrate for biodiesel fuel production was vegetable residues and/or waste liquors. The culture conditions should be chosen with a view to maximizing the biomass yield and monounsaturated fatty-acid content in the fungal lipids.

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 %.

Hydrofining of cycle oil using modified nickel-tungsten sulfide catalysts

The effect of palladium and ruthenium admixtures on the activity of an industrial NiW sulfide catalyst has been studied. It has been shown that Pd and Ru can increase the activity of the industrial catalyst in the hydrodesulfurization reaction of cycle oil by 8.0 and 2.8%, respectively. Under the experimental conditions, the hydrodearomatization of hydrocarbons composed of two or more rings results in the formation of monoaromatic hydrocarbons. The conversion of polyaromatic hydrocarbons in the temperature range of 260–300°C is 100%.

Modified mesoporous catalysts based on Al-HMS and Al-MCF for the oligomerization of α-olefins

High-performance decene-1 oligomerization catalysts based on mesoporous Al-HMS and Al-MCF aluminosilicates modified with an F-4SF sulfonated perfluorinated copolymer have been synthesized. Under batch conditions with a conversion of 90% and in a flow system with a conversion of 83%, these catalysts provide the formation of an oligomerization product with viscosity properties characteristic of poly-α-olefins, the precursors of poly-α-olefin oils.

Hydroisomerization of n-dodecane on bifunctional catalysts containing mesoporous aluminosilicates

The hydroisomerization of n-dodecane on bifunctional catalysts with mesostructured aluminosilicates as an active component has been studied. Aluminosilicates with an Si/Al atomic ratio of 5 to 48 have been prepared using hexadecylamine as a template. Catalyst supports contained 35 wt % mesoporous material and 65 wt % γ-Al2O3. The platinum loading of the catalysts was 0.5% of the support mass. It has been found that the catalysts based on mesoporous aluminosilicates with an Si/Al ratio of 10 and 22 exhibit the highest selectivity. In their presence, the conversion reaches 43–46 wt % with the selectivity for iso-C12H26 of more than 90%.

Hydroconversion of rosin acids in the presence of Pt-containing Al–HMS mesoporous aluminosilicate

The hydroconversion of a mixture of rosin acids over a Pt-containing mesoporous aluminosilicate catalyst has been studied. It has been shown that in a temperature range of 300–350°C at pressures of 30–50 atm and a feedstock/catalyst weight ratio of 20/1, rosin acids undergo complete decarboxylation to form naphthenic and naphthene-aromatic hydrocarbons. Under optimum process conditions, the yield of diesel fuel hydrocarbons is more than 85%. The resulting fraction can be used as a fuel component.