A series of catalysts were prepared from a granulated hierarchical (micro–meso–macroporous) NaYh zeolite: NaYh, H-NaYh, H-Yh, Li-NaYh, K-NaYh, Ca-NaYh, Mg-NaYh, and La-NaYh. Their physicochemical properties were characterized, and their catalytic activity and product selectivity were investigated in the aromatization of isophorone. The highest performance in the synthesis of 3,5-dimethylphenol was achieved in the presence of K-NaYh, the catalyst distinguished both by the highest basicity among the tested samples and by low concentrations of weak Brønsted acid sites and Lewis acid sites. This sample exhibited a 3,5-dimethylphenol selectivity of 78.6

The catalytic performance (activity and selectivity) of a FAU-type hierarchical NaYh zeolite, as well as of a series of modified samples, was investigated in the homocondensation of acetone. The modified samples were prepared from NaYh by ion exchange of Na+ for cations of alkali (Li+, K+), alkaline-earth (Ca2+, Mg2+), transition (Co2+, Ni2+), and rare-earth (La3+) metals, as well as by decationation (H-NaYh, HYh). The predominantly acidic zeolites (Ca-NaYh, Mg-NaYh, Co-NaYh, Ni-NaYh, La-NaYh, H-NaYh, and HYh) promoted the formation of acetic acid and mesitylene even at 250°C. The zeolites that contained alkali metal cations (Na+, Li+, and K+) exhibited activity only when the temperature was elevated. Starting from 350°C, NaYh and Li-NaYh promoted the formation of acetic acid. In contrast, the performance of K-NaYh under heating was characterized by the absence of acetic acid formation and a smooth increase in the selectivity towards isophorone (up to 23

Catalytic properties that mesoporous amorphous titanosilicate catalysts differing in physicochemical characteristics exhibit in cyclohexene oxidation with hydrogen peroxide to a mixture consisting mainly of alcohol and ketone were studied. The cyclohexene conversion and selectivity of formation of oxidation products depend both on the physicochemical properties of the titanosilicates studied (nature of active sites, porosity, etc.) and on the reaction conditions. The total selectivity with respect to the enol + enone fraction of 94

This study aimed to investigate the influence of the content of crystalline (10, 30, 60

The catalytic properties of mesoporous amorphous titanosilicate Ti–Si in acetone homocondensation at 250–350°С and mass feed space velocity of 0.5–10 h–1 were studied. The acetone conversion was 13–52 wt

The physicochemical properties of a series of catalysts based on granulated Na-Yh zeolite with the hierarchic (micro–meso–macro) pore structure (Na-Yh, HNa-Yh, MgO/Na-Yh, La2O3/Na-Yh, TiO2/Na-Yh) and the activity and selectivity of these catalysts in isophorone aromatization were studied. MgO/Na-Yh and La2O3/Na-Yh zeolites with high content of basic sites and low content of Brønsted acid sites are the most effective in the synthesis of 3,5-dimethylphenol: The 3,5-dimethylphenol formation selectivity reaches 63–69

The study investigates the catalytic performance of hierarchical granular Na–Yh zeolites promoted with metal oxides (designated as ZnO/Na–Yh, NiO/Na–Yh, Co3O4/Na–Yh, and CuO/Na–Yh) in the synthesis of quinolines from aniline and n-propanol. The highest aniline conversion and highest total quinoline selectivity (49 and 63

The study investigates the catalytic performance of microporous and granular micro–meso–macroporous zeolites (H-ZSM-5 and H-ZSM-5h, respectively) in synthesis of quinolines by the reaction of 2-aminoacetophenone with diketones (2,4-pentanedione or dimedone), known as the Friedländer synthesis. In the presence of H-ZSM-5h, 1-(2,4-dimethylquinolin-3-yl)ethanone ( 1a ) and 3,4-dihydro-3,3,9-trimethyl-1(2 H )-acridinone ( 1b ) were produced in 82 and 93% yields, respectively.

The study investigates the catalytic performance of Ni-modified granular samples of hierarchical porous Yh (FAU) zeolite, some of which were synthesized by ion exchange and others by impregnation. The samples were characterized by X-ray diffraction, X-ray fluorescence, low-temperature nitrogen adsorption/desorption (–196°C), scanning electron microscopy, hydrogen temperature-programmed reduction, and IR spectroscopy of adsorbed pyridine. The samples prepared by ion exchange of Na+ for Ni2+ exhibited high catalytic activity in oligomerization of pentene, specifically 98

Catalytic properties of ASM amorphous mesoporous aluminosilicates with different SiO 2 /Al 2 O 3 molar ratios (20, 40, 80) in oligomerization of 1-pentene and isoamylene fraction were studied. The yield of pentene oligomers is maximal on ASM-20 aluminosilicate and decreases with an increase in the SiO 2 /Al 2 O 3 molar ratio. The optimum conditions for preparing 1-pentene oligomers in the maximal yield (92–94%) were determined: 150–180°C, 10% catalyst. The yields of the oligomers obtained from the isoamylene fraction on ASM-20 and ASM-40 aluminosilicates are 76 and 74%, respectively (110°C, 10% catalyst), with dimers prevailing. Comparison of the catalytic properties of ASM-20 and 40 mesoporous aluminosilicates and H-Beta zeolite in oligomerization of these monomers shows that their activity is close, but the mesoporous materials exhibit higher stability in oligomerization. In addition, ASM aluminosilicates allow preparation of oligomers with broader molecular-mass distribution.

The study investigates the catalytic performance of microporous (H–Y) and micro–meso–macroporous (H–Yh, Fe2O3/H–Yh, PbO/H–Yh, and La–H–Yh ) FAU-type zeolites in the condensation of acetone with ammonia. In the presence of H–Yh, Fe2O3/H–Yh, and La–H–Yh, 2,4,6-trimethylpyridine was synthesized with selectivity of 54%, 58%, and 24%, respectively. In the presence of H–Y and PbO/H–Yh, the predominant reaction was acetone condensation, with the reaction products mostly consisting of diacetone alcohol and mesityl oxide.

The catalytic properties of a number of FAU (Y) zeolite samples (microporous zeolite H-Y, granular hierarchical zeolite H-Yh, zeolite H-USYh dealuminated by high-temperature steam treatment (HTST), and zeolite H-USYh a.t. dealuminated by HTST with subsequent acid treatment) in the oligomerization of 1-pentene. The samples were characterized by X-ray fluorescence analysis, X-ray powder diffraction analysis, low-temperature nitrogen adsorption–desorption, scanning electron microscopy, and temperature-programmed desorption of ammonia. It was determined that the total yield of pentene oligomers under the studied conditions (150°С, 10 wt % catalyst, 5 h) decreases in the order H-USYh a.t. (93%) ≈ H-Yh (93%) > H-Y (74%) > H-USYh (70%). The dealuminated sample H-USYh a.t., which has the largest mesopore volume, showed high stability in 1-pentene oligomerization at 180°C. The conversion of the monomer in its presence remained unchanged during 5 cycles of operation without catalyst regeneration, and the yield of pentene oligomers after 5 cycles decreased by 39%. Microporous zeolite H-Y lost activity already after the second cycle.

Изучено влияние предварительной выдержки “белой” сажи марки БС-100 при 150–155°C в течение 6–7 ч и условий кристаллизации на характеристики образцов порошкообразного цеолита типа MOR (степень кристалличности, дисперсный состав и адсорбцию молекул С6Н6), а также на их каталитические свойства в реакции димеризации -метилстирола.

This paper reports on the control of strong acid sites in SAPO-11 molecular sieve crystals using different silica sources. The crystallization process of the SAPO-11 molecular sieves was performed using silicon sources with different particle sizes, i.e., fumed silica (200 nm), colloidal silica (22 nm), and SiO2 sol prepared by the sol-gel method (4 nm). The SiO2 sol proved to have a significant effect on the acidic properties, morphology and crystal size of SAPO-11 molecular sieve. Moreover, more efficient incorporation of silicon is achieved, providing an increased concentration of acid sites. The SAPO-11 intergrown crystals with a size of 100-300 nm exhibited hierarchical pore structure (SBET - 250 m(2)/g and Vmeso - 0.27 cm(3)/g) were synthesized using the SiO2 sol precursor. The SAPO-11 molecular sieves were tested in the reaction of a-methylstyrene dimers synthesis. The SAPO-11 samples, synthesized by SiO2 sol showed the highest monomer conversion and linear dimer selectivity.

The study investigates the catalytic properties of microporous (H–Y) and micro-meso-macroporous (H–Y-mmm) FAU-type zeolites in the synthesis of 2-methyl-5-ethylpyridine (MEP) by the reaction of acetaldehyde with ammonia. At 150°C, an acetaldehyde to ammonia molar ratio of 1 : 3, and a catalyst content of 10 wt %, a MEP yield of 58% (0.95H–Y) and 63% (0.95H–Y-mmm) was achieved with a MEP selectivity of 91 and 93%, respectively. The examination of the catalyst stability revealed that hierarchical H–Y-mmm zeolites ensure a 100% MEP selectivity during 4–5 cycles with a slight decline in the catalytic activity, while H–Y zeolites are active during the first cycle only.