A method was developed for the synthesis of granulated zeolite NaY with high degree of crystallinity, developed porous structure, mechanical strength of 2.5–2.9 kg/mm 2 , and having an adsorption capacity comparable to the adsorption capacity of a powdery zeolite of the same structural type. The method is based on hydrothermal crystallization of granules obtained by mixing powdered zeolite NaY, kaolin, and fumed silica (silica gel or aerosil) from reaction mixtures of the following composition: (2.2–2.6)Na 2 O∙Al 2 O 3 ∙(6.5– 7.5)SiO 2 ∙(155–165)H 2 O at a temperature of 98–100 °C for 48 hours. The crystallization stage was preceded by the stage of preliminary exposure of the granules at a temperature of 25–30 °C for 12–24 hours. The composition of the initial granules should strictly corre-spond to the intervals: NaY zeolite 55–70% by mass, kaolin 23–40% by mass, fumed silica (silica gel or aerosil) 3–7% by mass. It was found that going beyond the established inter-vals of both the composition of the initial granules and the reaction mixture leads to a de-crease in performance and, accordingly, the quality of the product. It was revealed that the nature of the silicon-containing raw materials used in the formation of the initial granules does not affect the adsorption and strength characteristics of crystallization products.

Highly efficient binder-free catalysts, based on zeolite Y, for the liquid-phase alkylation of benzene with ethylene have been synthesized. The catalysts have been modified by treating with aqueous solutions of hydrochloric and citric acids to remove extra-framework aluminum formed during the partial dealumination of zeolite Y. The synthesized catalysts have been tested in the alkylation of benzene with ethylene at a temperature of 200°C, a pressure of 2.5 MPa, a benzene : ethylene molar ratio of 5 : 1, and a benzene feed space velocity of 5 h−1. Over the modified catalyst, the ethylbenzene (EB) content in the alkylate increases by 27% and the EB selectivity increases by 5% compared to the initial Y zeolite.

A multistage synthesis of the catalyst for the gas-phase alkylation of benzene with ethylene is implemented. A highly active catalyst is synthesized from zeolite ZSM-5 using thermal-vapor treatment. The obtained catalyst possesses an optimal acidity, which makes it possible to achieve a higher yield of ethylbenzene compared to the commercial catalyst based on ZSM-5 (88 and 62.7 wt %, respectively), an approximately equal ethylbenzene selectivity, and an almost three times lower concentration of the undesirable xylene impurity in an alkylate (0.004 and 0.011 wt %, respectively) in the gas-phase benzene alkylation with ethylene.

В результате проведенных исследований синтезирован катализатор для газофазного процесса алкилирования бензола различными алкилирующими агентами в этилбензол. Для получения катализатора цеолит НZSM-5 смешивали с псевдобемитом в соотношении 70/30 % масс. Полученную массу формовали в гранулы путем экструзии. Гранулы высушивали в течение 3 ч при температуре 120–150 °С, затем прокаливали в течение 4 ч при 650 °С в атмосфере воздуха, после чего подвергали термопаровой обработке в атмосфере водяного пара при температуре 500 °С в течение 1 ч. С использованием синтезированного катализатора проводили реакции алкилирования бензола этиленом, этан-этиленовыми фракциями различных составов и этаном при температуре 400 °С, давлении 2,5 МПа, мольном соотношении бензол : алкилирующий агент 7 : 1 (в пересчете на 100 %-ный этилен), объемной скорости подачи бензола 15 ч–1. Реакцию алкилирования бензола этаном проводили в тех же условиях, мольное соотношение бензол : этан 7 : 1. При использовании в качестве алкилирующего агента этан-этиленовой фракции, содержащей 80 % об. этилена и 20 % об. этана, вместо этилена полимеризационной чистоты в реакции алкилирования бензола на синтезированном катализаторе содержание этилбензола в алкилате увеличивается на 5,0 %, а побочных продуктов диэтилбензолов и полиалкилбензолов уменьшается на 7,6 %. СИНТЕЗ КАТАЛИЗАТОРА И ГАЗОФАЗНОЕ АЛКИЛИРОВАНИЕ БЕНЗОЛА ЭТИЛЕНОМ, ЭТАН-ЭТИЛЕНОВЫМИ ФРАКЦИЯМИ И ЭТАНОМ С ЕГО ИСПОЛЬЗОВАНИЕМ

As a result of the research, a catalyst was synthesized for the alkylation of benzene with ethylene based on zeolite ZSM-5 without binders. To obtain a catalyst mix 24 - 37 wt. % powdered zeolite ZSM-5 with 7 - 11 wt. % kaolin, 53 - 60 wt. % ground silica gel and 3 - 5 wt. % of oligomeric orthosilicic acid esters. The mixture is moistened, molded into granules by extrusion, then dried and calcined in an atmosphere of air. Then the granules are subjected to hydrothermal crystallization in the reaction mixture of the composition (3,0 - 4,0)Na2O ∙ (0,5 - 2,3)R ∙ Al2O3× ×(60 - 80)SiO2 ∙ (450 - 900)H2O, washed with demineralized water, treated aqueous solutions of ammonium salts to a degree of substitution of Na+ cations in the zeolite at least 97 %, again washed with demineralized water, dried and calcined. Using the synthesized catalyst, alkylation of benzene with ethylene is carried out at a temperature of 400 °C, a pressure of 2,5 MPa, a mass ratio of benzene : ethylene 18 : 1, and a bulk flow rate of benzene of 15 h - 1. The catalyst provides a high content (18,2 - 18,8 wt. %) of ethylbenzene in the alkylate.

As a result of the research, catalysts were synthesized and their properties were studied in the transalkylation of benzene with diethylbenzenes. Catalysts have a molar ratio of SiO2/Al2O3 in the range of 8,0 - 19,5; 100 % crystallinity, mechanical crushing strength of 2,3 kg/mm2, contain not more than 0,5 % wt. Na2O and provide: the conversion of diethylbenzenes 82,5 - 83,0 %, the concentration of ethylbenzene in transalkylate 21,0 - 21,5 % wt.

A set of studies have made it possible to develop a method for the synthesis of high-silica zeolite NaY-FS, which has a high adsorption capacity and a developed secondary porous structure. The method involves mixing kaolin with powdered zeolite NaY, polyvinyl alcohol (PVA), and fumed silica (FS) in an amount to have the total content of components in the mixture as follows (wt %): zeolite NaY (molar ratio SiO 2 /Al 2 O 3 = 5.5–7.0) 55–70, PVA 1–2, fume silica 3‒7, and kaolin the rest; moistening and stirring the mixture until a homogeneous mass, shaping granules; their calcining; hydrothermal crystallization in a sodium silicate solution from reaction mixtures with the composition (2.4‒3.6) Na 2 O ⋅ Al 2 O 3 ⋅ (10‒12) SiO 2 ⋅ (180‒220) H 2 O; and washing and drying the granules. In addition, the crystallization kinetics of zeolite NaY-FS from the reaction mixtures of these compositions has been studied.

The base catalyst HY-BS, which is binder-free zeolite Y in the acid H+ form, has been synthesized and modified with hydrochloric and citric acid solutions. It has been shown that all the obtained catalysts exhibit high activity and selectivity in the reaction of liquid-phase alkylation of benzene with ethylene. It has been first found that the ethylbenzene concentration in the alkylate and the selectivity for ethylbenzene in the liquid-phase benzene alkylation reaction on the catalyst modified with 0.3 N hydrochloric acid are higher when either the hydrogenated or the nonhydrogenated ethane–ethylene fraction of pyrolysis is used as an alkylating agent instead of polymerization-grade ethylene.

Quantum chemistry and chemical thermodynamics methods have been used to calculate the energy characteristics of the direct alkylation reaction of benzene with ethane catalyzed by H-ZSM-5, an unmodified zeolite in the decationized form. It has been shown that the reaction of ethylbenzene synthesis from benzene and ethane with a small yield is thermodynamically feasible at temperatures below 400°C. The catalyst H-ZSM-5 significantly reduces the energy of the formation reaction of the benzyl and ethyl radicals.

A catalyst for alkylation of benzene with ethylene to ethylbenzene has been prepared by mixing 70% H+-ZSM-5 zeolite having a silica ratio of 30 with 30% pseudoboehmite followed by shaping granules, their drying, and calcining for 6 h at 650°C in air. A part of the catalyst has been treated by steaming with 100% steam at 600°C for 3 h. The physicochemical and catalytic properties of catalyst samples have been studied. The catalysts have been tested in a laboratory setup in the temperature interval of 380–450°C at 2.5MPa, a benzene space velocity of 15 h−1, and a benzene/ethylene molar ratio of 7: 1. The properties of EBEMAX-1, an imported analogue of the catalysts have been studied under the same conditions. It has been found that the synthesized catalysts are not inferior to the imported sample in the catalytic properties.

Currently, facilities for benzene to ethylbenzene (EB) gas-phase ethylene alkylation in the presence of zeolite-containing catalysts have been advantageously applied in industry. Advantages of producing EB on zeolite catalysts, compared with the traditional Friedel-Crafts alkylation, are the lower investment and operating costs for the implementation of the process, absence of corrosion aggressive environment and of need for waste disposal, high EB yield and complete regenerability of catalyst. JSC “Gazprom neftekhim Salavat” implemented the technology of production of ethylbenzene by ethylene alkylation of benzene with the help of zeolite catalyst. Due to the lack of domestic industrial catalysts on JSC “Salavatnefteorgsintez” imported catalyst is used, so relevant research aimed at the creation of a domestic catalyst for the above process. Granulated catalyst systems containing 70 and 50 wt% crystalline aluminosilicate were prepared by mixing of produced by LLC “Ishimbai Specialized Catalysts Chemical Plant” zeolite ZSM-5 (SiО 2/Аl 2О 3=30) and pseudoboehmite followed by extrusion molding, drying and calcination at 640-650 oC in air atmosphere for 4-6 hours. Chemical and phase composition, characteristics of the porous structure, adsorption and acidic properties of the synthesized samples were studied by methods of XRF and XRD analysis, infrared spectroscopy, scanning electron microscopy, adsorption measurements and mercury porosimetry.