M. O. Kazakov

Hydroisomerization of benzene-containing gasoline fractions on a Pt/SO42−-ZrO2-Al2O3 catalyst: II. Effect of chemical composition on acidic and hydrogenating and the occurrence of model isomerization reactions

The acidic and hydrogenating of Pt/SO42−-ZrO2-Al2O3 samples containing from 18.8 to 67.8 wt % Al2O3 as a support constituent were studied by the IR spectroscopy of adsorbed CO and pyridine, and the model reactions of n-heptane and cyclohexane isomerization on these catalysts were examined. The total catalyst activity in the conversion of n-heptane decreased with the concentration of Al2O3; this manifested itself in an increase in the temperature of 50% n-heptane conversion from 112 to 266°C and in an increase in the selectivity of isomerization to 94.2%. In this case, the maximum yield of isoheptanes was 47.1 wt %, which was reached on a sample whose support contained 67.8 wt % Al2O3. A maximum yield (69.6 wt %) and selectivity (93.7%) for methylcyclopentane formation from cyclohexane were also reached on the above catalyst sample. This can be explained by lower concentrations of Lewis and Brønsted acid sites in the Pt/SO42−-ZrO2-Al2O3 system, as compared with those in Pt/SO42−-ZrO2. The experimental results allowed us to make a preliminary conclusion that the Pt/SO42−-ZrO2-Al2O3 catalyst whose support contains 67.8 wt % Al2O3 is promising for use in the selective hydroisomerization of benzene-containing gasoline fractions in the thermodynamically favorable process temperature range of 250–300°C.

FTIR Spectroscopy of Adsorbed Probe Molecules for Analyzing the Surface Properties of Supported Pt (Pd) Catalysts

Supported metal catalysts are important for many fields of applied chemistry, including chemical synthesis, petrochemistry, environmental technology, and energy generation/storage. For prediction of catalyst performance in a chosen reaction and optimization of its functions, it is necessary to know the composition of the surface active sites and have methods for estimating their amount and strength. One of the most available and well-developed methods for studying the composition and structure of the surface functional groups of supported metal catalysts is vibrational spectroscopy, in particular with the use of adsorbed probe molecules.

Formation of platinum sites on layered double hydroxide type basic supports: III. Effect of the mechanism of [PtCl6]2− complex binding to aluminum-magnesium layered double hydroxides on the properties of supported platinum in Pt/MgAlOx catalysts

While synthesizing platinum catalysts supported on aluminum-magnesium oxides (Pt/MgAlOx), we established that, in the binding of the Pt(IV) chloro complex to aluminum-magnesium layered double hydroxides (LDHs), the mechanism of the metal complex-support interaction depends on the nature of the interlayer anion of the LDH. The synthesis may yield chemically identical Pt/MgAlOx samples differing in the particle size and electronic structure of supported platinum. The higher dehydrogenating activity of the catalyst obtained by binding the [PtCl6]2− complex in the interlayer space of LDH via exchange with interlayer OH− anions is possibly due to the larger proportion of metallic platinum (Pt0) in this catalyst. In the catalyst prepared from hydrolyzed platinum complex species using LDH with CO32− interlayer anions, platinum is mainly in an oxidized state similar to Pt2+.

Liquid-phase isobutane alkylation with butenes over aluminum chloride complexes synthesized in situ from activated aluminum and tert -butyl chloride

The liquid-phase interaction between isobutane and butenes at 303 K and 2.5–3.0 MPa has been investigated using activated aluminum (Al*)-tert-butyl chloride (TBC) model system (TBC: Al* = 0.35−4 mol/mol). It has been demonstrated by attenuated total reflection FT-IR (ATR-FT-IR) spectroscopy that the catalytically active aluminum chloride complexes forming in situ in the hydrocarbon medium vary in composition. Alkylation as such takes place at equimolar proportions of the reactants (TBC: Al* = 1: 1) and butenes feed 1mass flow rate of 5 h−1 per gram of Al*. According to ATR-FT-IR data, the most abundant aluminum complexes resulting under these conditions are the AlCl4− and Al2Cl7− ions and, probably, the molecular complex AlCl3 · sec-C4H9Cl. In a fourfold excess of TBC over Al* at butenes mass feed rate of 2.5 h−1, isobutane undergoes self-alkylation. In this case, the Al2Cl7− ion is not detected and the most abundant complexes are AlCl4−, Al3Cl10− and the molecular species AlCl3 · tert-C4H9Cl. It is hypothesized that the Al2Cl7− ion plays the key role in the liquid-phase alkylation of isobutane with butenes.

A new catalyst for the deep hydrotreatment of vacuum gas oil, a catalytic cracking feedstock

A new CoNiMo/Al2O3 deep vacuum gas oil hydrotreatment catalyst designed for the production of catalytic cracking feedstocks containing 200–500 ppm of sulfur is developed. The method for its preparation includes the following stages: the preparation of a support with specified textural, strength, and granulometric characteristics; the synthesis of bimetallic (Co-Mo and Ni-Mo) complex compounds in solution; and their deposition and drying. The new sample is compared to current domestic and imported industrial analogs according to their physicochemical (texture, morphology, active phase structure) and catalytic characteristics and analyzed. It is shown that the catalyst allows hydrotreatment at temperatures 5–20°C lower and target fraction yields 4–13% higher than all the reference samples. The high activity of the new catalyst is due to the formation of one-layer trimetallic Co(Ni)MoS phase particles at the stage of its sulfidation. The catalyst preparation technique is ready for industrial use (OOO Sintez, Barnaul, 1000 t/yr), and the principal technological regimes of the hydrotreatment of vacuum gas oil on the developed catalyst are determined.

Use of Platinum Carbonyl Complexes in the Synthesis of Pt/MgAlO x Catalysts

Pt/MgAlOx samples have been obtained by the adsorption of platinum carbonyl complexes on aluminum-magnesium oxides with Mg: Al = 2, 3, and 4. The composition of the adsorbed complexes has been determined. The catalysts synthesized from the carbonyl precursor show a higher activity in propane dehydrogenation and are less prone to deactivation than the catalysts prepared using platinum chloro complexes.

Hydroisomerization of benzene-containing gasoline fractions on a Pt/SO42−-ZrO2-Al2O3 catalyst: III. The hydrogenating properties of the catalyst

The properties and state of platinum in Pt/SO42−-ZrO2-Al2O3 catalysts with various alumina contents have been investigated in benzene hydrogenation as a model reaction using IR spectroscopy, temperature-programmed reduction, and H2 chemisorption. As the Al2O3 content is raised, the hydrogenating activity of the catalyst increases, which is due to the increasing proportion of metallic platinum on the surface.

Hydroisomerization of reformed gasoline on the Pt/SO42−-ZrO2 catalyst

The features of the hydroisomerization of C5–C12 alkane and aromatic hydrocarbons present in reformed gasoline over a catalyst based on platinum-promoted sulfated zirconium dioxide were studied.

Hydroisomerization of benzene-containing gasoline fractions on Pt/SO42−-ZrO2-Al2O3 catalyst: Conversion of model and real feedstocks

The conversion of benzene-containing gasoline fractions on the bifunctional Pt/SO42−-ZrO2-Al2O3 catalytic system with different compositions of the support is studied. Using the results from hydroisomerization of a heptane-benzene model mixture, it is shown that a system with 67.8 wt % of aluminum oxide in its support has the best catalytic properties. For the IBP-85°C industrial benzene-containing fraction (23.7 wt % of benzene), it is established that the given catalyst ensures the complete removal of arenes from the benzene-containing fraction while raising its research octane number by 2.2–3.3 points and retaining a high yield of liquid products at levels of 98.7 wt % and higher.

Influence of Temperature on the Hydrogenation of Oil Shale from the Kashpir Deposit

The effect of the hydrogenation temperature of oil shale from the Kashpir deposit on the yield and the properties of the resulting liquid hydrocarbons and gasoline and diesel fractions separated from them was studied. It was found that synthetic oil can be obtained from high-sulfur oil shale with the use of hydrogenation processing. In this case, it is possible to extract more than 90% of the organic matter of oil shale. Depending on the temperature of this processing, the sulfur content of the synthetic oil varied from 2.8 to 4.2 wt %, and the nitrogen and light fraction contents varied from 1.3 to 1.6 and from 34 to 67 wt %, respectively.