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The effect of the support nature on the performance of hexane isomerization reaction was studied for the sulfated zirconiа catalysts supported on SiO2 and Al2O3, which have different textural characteristics. It was shown that a higher conversion of hexane is reached over sulfated zirconiа catalysts supported on aluminum oxides. IR spectroscopy of adsorbed CO revealed that the concentration of Broensted acid sites (BAS), which are characterized by adsorbed CO with the absorption band (a.b.) at 2170 cm–1, and strong Lewis acid sites (LAS), which are characterized by adsorbed CO with a.b. at 2210 and 2224 cm–1, is higher in the Al2O3-supported catalysts compared to the SiO2-supported ones. In the Al2O3-supported catalysts with different textural characteristics, an increase in the contribution of LAS to the total acidity essentially increases the yield of high-octane 2,2-dimethylbutane and the depth of hexane isomerization.

Isomerization of heptane and hexane and their mixtures in the presence of Pt/WO3-ZrO2 catalysts with the tungsten oxide content of 10–35 wt.% was studied. The best characteristics of isomerization of the С6–С7 alkanes mixture were observed on the catalysts with the WO3 content of 15–20 wt.%. According to ammonia thermodesorption data, the number of acid sites typically increases in this range of tungsten oxide content; according to IR spectroscopy of adsorbed CO, this occurs mostly with an increase in the number of Broensted acid sites.

The paper reports data on the development and investigation of the advanced catalysts for reforming and isomerization of gasoline fractions, which were performed at the Center of New Chemical Technologies BIC SB RAS, particularly the commercial operation of the reforming catalyst PR-81. A new catalyst with an increased acidity, which provides a decrease in the content of aromatic hydrocarbons in reformate by 3–5 wt.%, was developed for the reforming of gasoline fractions. A new sulfated zirconia catalyst supported on the porous alumina matrix was devised for isomerization of the fraction of C5–C6 hydrocarbons. An efficient tungstated zirconia catalyst was suggested for isomerization of the fraction of C7 hydrocarbons. The indicated catalysts are employed in the proposed scheme of integrated reforming and isomerization processes, which ensures the production of motor gasolines Euro-5 and 6, as well as the promising gasolines with a decreased content of aromatic hydrocarbons.

A sequence of steps in the synthesis of supported Pt/SO4/ZrO2/Al2O3 catalysts was studied. The introduction order of the active component was shown to substantially change the catalytic properties in isomerization of n-hexane. The sequence of introducing the components, their concentration, and the number of support impregnations make it possible to provide high performance in isomerization of n-hexane in the presence of supported sulfated zirconia catalysts.

The modifying effect of iron, which is introduced in different steps of the synthesis from different precursors, on the reaction of n-hexane isomerization in the presence of supported Pt/SZ/Al2O3(Fe) catalysts was studied. It was shown that the addition of Fe substantially affects the acidic properties of the catalysts, increasing mostly the content of Lewis acid sites. When iron is deposited on alumina or introduced into aluminum hydroxide, the yield of the sum of hexane isomers increases to 80-85 wt.% and the yield of the sum of dimethylsubstituted isomers, to 28-33 wt.%

The paper deals with the modifying effect of tin, iron and manganese, which are introduced at different stages of the synthesis, on the reaction of n-hexane isomerization in the presence of supported Pt/SZ/Al2O3 catalysts. The addition of a modifier was shown to affect the catalytic performance in isomerization reaction. The activity of modified catalysts increases due to redistribution of Broensted and Lewis acid sites with the preferential increase in the LAS content. The deposition of iron and manganese on alumina or the introduction of tin, iron and manganese in aluminum hydroxide increases the yield of the sum of hexane isomers to 80-85 wt.%, and the yield of the sum of dimethylsubstituted isomers to 28-33 wt.%.

The effect of phase composition and textural characteristics of alumina on physicochemical and catalytic properties of supported sulfated zirconia catalysts in isomerization of n-hexane was studied. The catalysts were examined using atomic emission spectroscopy, nitrogen adsorption-desorption, XRD, TPD of ammonia, and IR spectroscopy of adsorbed pyridine. Samples were tested in the reaction of n-hexane isomerization. It was shown that the use of α-Al2O3 as the support leads to the formation of a mixture of monoclinic and tetragonal zirconia phases and decreases the catalytic activity. The use of γ and θ alumina species as the supports stabilizes the tetragonal zirconia phase, which is active toward isomerization of n-hexane. Investigation of acid sites revealed that the increased contribution of Lewis acid sites in supported sulfated zirconia catalysts enhances the catalytic activity and increases the yield of hexane isomers.

The effect of the mordenite acidic modulus (SiO2/Al2O3, 20 and 30) of Pt/MOR/Al2O3 catalysts on the heptane isomerization reaction is investigated. The content of zeolite in the catalysts is varied from 10 to 50 wt %, with platinum applied to the samples from solutions of different precursors: H2PtCl6 and [Pt(NH3)4]Cl2. It is established via the TPD of ammonia and FTIR spectroscopy (the adsorption of NH3 and СО) that the total acidity of zeolite falls as the modulus grows: the number of Bronsted (BAC) and Lewis (LAC) acidic sites is reduced, accompanied by an increase in the strength of their acidity. The catalysts are tested in the n-heptane isomerization reaction. It is shown that the selectivity of n-heptane isomerization falls substantially when the acidic mordenite modulus is increased from 20 to 30.

Sulfated zirconia catalysts supported on SiO 2 and Al 2 O 3 were prepared and studied. Phase composition of the catalysts, acidic properties in CO adsorption, and textural characteristics were assessed. Activity of the catalysts in isomerization of n-hexane was measured. Alumina was shown to be a promising support for the synthesis of such catalysts. A new step of additional sulfation after platinum deposition was proposed for the synthesis of alumina-supported catalysts. It was found that strong Lewis acid sites with CO absorption bands at 2210 and 2224 cm -1 are formed in the catalysts. The yield of the sum of hexane isomers for the alumina-supported catalysts reached 80 wt.%.

An attempt was made to use particle swarm optimization (PSO) method for solving the inverse chemical kinetics problem for the n-hexane isomerization process on a sulfated zirconia catalyst sample. A perspective supported isomerization catalyst based on sulfated zirconia supported on alumina was chosen. Also the optimal coefficients for this problem were chosen. Method of determining the kinetic rate constants for the hexane isomers interconversion was tested. Model of hexanes interconversion based on calculated kinetic rate constants was built.

The modifying effect of tin introduced at different steps from various tin precursors on characteristics of n-hexane isomerization in the presence of supported Pt/SZ/Al2O3(Sn) catalysts was studied. The addition of Sn was shown to substantially affect the porosity characteristics of the catalysts and dispersion (particle size) of the active phase of tetragonal zirconia. The use of Sn(IV) hydroxide as an additive to the initial aluminum hydroxide allowed obtaining the supported catalyst with the particle size of the t-ZrO2 active component 3.2 nm and specific surface area of zirconia 294 m2/g. At a zirconia content of ca. 20 wt.% the catalytic performance of the catalyst in n-hexane isomerization approached the performance of the bulk samples in which ZrO2 content attained 70-75 wt.%.The modifying effect of tin introduced at different steps from various tin precursors on characteristics of n-hexane isomerization in the presence of supported Pt/SZ/Al2O3(Sn) catalysts was studied. The addition of Sn was shown to substantially affect the porosity characteristics of the catalysts and dispersion (particle size) of the active phase of tetragonal zirconia. The use of Sn(IV) hydroxide as an additive to the initial aluminum hydroxide allowed obtaining the supported catalyst with the particle size of the t-ZrO2 active component 3.2 nm and specific surface area of zirconia 294 m2/g. At a zirconia content of ca. 20 wt.% the catalytic performance of the catalyst in n-hexane isomerization approached the performance of the bulk samples in which ZrO2 content attained 70-75 wt.%.

Supported Pt/SZ/Al2O3 catalysts prepared via the thermolysis of zirconium sulfate in support pores are studied. The content of the active component (sulfated zirconia) in the catalysts is 25–30 wt %, 2–2.5 times lower than in massive catalysts equivalent in their catalytic characteristics. Tests in the isomerization of n-hexane are performed. It is shown that the total yields of 2,2- and 2,3-dimethylbutanes (DMB) on the supported catalysts at temperatures of 140–160°C are 34–36 wt % at a stable C5+ catalyzate yield of 96–98 wt %, comparable to the results obtained on industrial isomerization catalysts based on sulfated zirconia. The results indicate that the supported Pt/SZ/Al2O3 catalysts can be used in the isomerization of C5-C6 fractions to synthesize environmentally friendly high-octane gasoline components.

Supported platinum catalysts based on ferrierite type zeolite with Pt content in the range of 1.3–2.8 wt % are prepared. The localization of Pt in zeolite channels is studied for the first time. It is shown that the platinum localized in them increases the yield of products from the selective hydrocracking of n-hexane. Platinum on the outer surface of the zeolite crystals participates in the transformation of n-hexane in the direction of forming hydrocarbons with isomeric structure. The catalysts can be used to improve the octane rating of reformed gasoline, owing to the selective removal of low-octane n-paraffin hydrocarbons and the increase of the portion of high-octane isoparaffin hydrocarbons in the catalytic reforming gasolines.