Catalyst For Alkylation Of Benzene Research Articles

ZnxZr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

ZnxZr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

The dependence of high catalytic performance on the tunable oxygen vacancy in the CZxS/Zn‐HZSM‐5 bifunctional catalyst for alkylation of benzene and syngas

AbstractA bifunctional catalyst (CZxS/Zn‐HZSM‐5) with tunable oxygen vacancy was prepared by coupling ceria–zirconia solid solution (CZxS) and zinc‐modified HZSM‐5 zeolite (Zn‐HZSM‐5). The characterization results indicated that the formation of CZxS by insertion of zirconia (Zr) atoms into cerium oxide (CeO2) could generate more oxygen vacancy due to the structural distortion. With the increasing of Zr content, the oxygen vacancy concentration on the surface of CZxS increased as well, which reached a maximum for a Zr/Ce ratio of 4 and then decreased by further increase of Zr content. The dependence of oxygen vacancy concentration in the CZxS/Zn‐HZSM‐5 bifunctional catalyst on their catalytic performance in the benzene alkylation with syngas was further investigated. The result exhibited that the oxygen vacancy was the site for CO activation, and the more oxygen vacancy, the better catalytic performance. The best catalytic activity, with a CO conversion of 33%, the benzene conversion of 30% and the total toluene and xylene selectivity of 92% was obtained over the bifunctional catalyst CZ4S/Zn‐HZSM‐5 with the highest oxygen vacancy concentration.

Synthesis of hierarchical nanocrystalline β zeolite as efficient catalyst for alkylation of benzene with benzyl alcohol.

To develop an efficient solid acid catalysts for the Friedel–Crafts alkylation reaction, especially for involving bulky molecules, the direct synthesis of hierarchical nanocrystalline β zeolites were achieved by using amphiphilic organosilane ([(CH3O)3SiC3H6N(CH3)2C18H37]Cl, TPOAC) as collaborative structure-directing agent (SDA). The growth evolution of β crystals and the influence of TPOAC/SiO2 molar ratio on the mesoporous structure, crystal size, and acidic properties of β zeolites were investigated and discussed in detail. The characterization results reveal that intracrystalline mesopores and intercrystalline mesopores/macropores via the stacking of β nanocrystals were generated over the hierarchical β zeolites. Moreover, most of the strong acid sites were well remained compared with the conventional microporous β zeolite. Consequently, the hierarchical nanocrystalline β zeolite synthesized under the optimized synthesis conditions shows improved specific catalytic activity of acid sites (turnover number, TON) in alkylation of benzene with benzyl alcohol, which can be attributed to the integrated balance of considerable mesoporosity, accessibility of the acid sites, and well-remained strong acid sites in the hierarchical β zeolite.

Synthesis of a Zeolite-Containing Catalyst for Gas-Phase Alkylation of Benzene with Ethylene

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.

Construction of a tandem HZSM-5 with CuZnAl catalyst for alkylation of benzene with syngas

A bifunctional catalyst composed of ZSM-5 and Cu–Zn–Al shows an outstanding catalytic performance in the alkylation reaction of benzene with syngas.

Nano-12-Tungstophosporic Acid Cesium Salt Synthesized by Ultrasound as Catalyst for Alkylation of Benzene with dec-1-ene

Abstract Nano 12-tungtophosphoric acid cesium salt (Cs-TPA) was synthesized under ultrasonic irradiation in nanoscale. The obtained catalyst was characterized by various methods. These analyzes indicate that the chemical structure and crystallinity of nano Cs-TPA remained unchanged while its morphology was found to be different from traditional Cs-TPA which is in irregular shape, becoming spherical with an average particle size of about 50 nm. Nano Cs-TPA was examined in the alkylation of benzene with dec-1-ene, its catalytic activity was remarkably enhanced compared to its original state. The catalyst reusability experiment also showed that the activity of nano Cs-TPA does not decrease even after five reused cycles.

Alkylation of benzene over Fe-based metal organic frameworks (MOFs) at low temperature condition

Iron based metal organic frameworks as novel catalysts were developed for ethylbenzene synthesis by alkylation of benzene with ethanol in low temperature gas phase conditions employing MIL-101 (Fe) and MIL-88 (Fe) catalysts. Both of catalysts were synthesized with solvothermal method. Catalysts characterization were performed using X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), and Field Emission Scanning Electron Microscope (FE-SEM). Nitrogen adsorption measurements were done to determining the catalyst surface area and pore volume and pore size distribution. Also the acidity of catalysts was measured using NH3-TPD. The catalysts activity and product selectivity for ethylbenzene production have been investigated in a specially designed flow microreactor in gas phase. Effects of temperature and space velocity at constant benzene to ethanol ratio (3:1 volumetric ratio) have been studied for catalyst performance and ethylbenzene selectivity and yield. In comparison of two synthesized catalysts, MIL-88 showed a higher performance (100% ethanol conversion, 72% benzene conversion and 76% ethylbenzene selectivity at 175 °C). The main byproduct was recognized as toluene. Long reaction time for both catalysts showed no decline in conversion and selectivity of desired product. The BET measurement and the FTIR spectra of used catalysts revealed these Fe-based metal organic frameworks are stable catalysts for alkylation of benzene by ethanol.

Synthesis and investigation of ZSM-5 zeolite-based catalysts for benzene alkylation with ethylene

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.

Effect of Desilication on the Performance of Hierarchical ZSM-11 Catalysts for Alkylation of Benzene with Dimethyl Ether

Hierarchical ZSM-11 zeolites (Z-xat) were prepared by treating the pristine ZSM-11 zeolite in a solution of NaOH with different concentrations (C NaOH). It was found the porosity and acidity (concentration, strength, distribution and accessibility factor of Bronsted and Lewis acid sites) of modified ZSM-11 zeolite changed obviously with C NaOH. When used for alkylation of benzene with dimethyl ether, the modified Z-xat exhibited better reaction stability than the unmodified HZSM-11 zeolite. Typically, the reaction stability of Z-xat zeolite catalysts was directly related to the mesopore volume, besides the weak-medium acid concentrations determined by Py-IR technique.

Differences between Zn/HZSM-5 and Zn/HZSM-11 zeolite catalysts in alkylation of benzene with dimethyl ether

HZSM-11 zeolite supported Zn catalysts with different Zn contents (xZn/HZSM-11A) were prepared. In the alkylation of benzene with dimethyl ether (DME) in a fixed bed reactor, the catalyst with Zn content of 6 wt% (6Zn/HZSM-11A) showed appropriate performance. Focus was put on the comparison between 6Zn/HZSM-5 and 6Zn/HZSM-11 with the same crystal size of 600–800 nm, and also with the similar BET surface area, micropore volume, Si/Al2 molar ratio, and acidity. In the alkylation of benzene with DME, the 6Zn/HZSM-11 showed better activity and stability, and especially enhanced the conversion of benzene and selectivities to xylene and trimethylbenzene, compared with the 6Zn/HZSM-5. This was mainly related to the higher adsorption capacity and adsorption-desorption rates to the three adsorbates (benzene, m-xylene and 1,3,5-trimethylbenzene) over the 6Zn/HZSM-11 in comparison with the 6Zn/HZSM-5.

Selective zeolite catalyst for alkylation of benzene with ethylene to produce ethylbenzene

In this work, a selective catalyst of BXE ALKCAT zeolite has been developed with about 30 % of ZSM-5 balanced with kaolinite, and applied for gas-phase alkylation of benzene (BZ) with ethylene (E). The catalyst has been tested in a fixed-bed down-pass flow reactor under different conditions of temperatures ranging between 300 and 450 °C with BZ to E mole ratios ranging between 1:1, 3:1 and 6:1 under atmospheric pressure and space velocity ranges between 0.1 and 150 h−1. The BXE ALKCAT zeolite catalyst has been characterized using: scanning electron microscope, X-ray diffraction, specific surface area, pore volumes, pore size distributions, X-ray photoelectron spectroscopy, and differential thermal analysis, and thermo-gravimetric analyses. Ethylbenzene was the main product of alkylation, and diethylbenzene isomers (ortho-, meta-, and para-) were the minor products. In the case of 1:1 mol ratio of BZ to E, the selectivity of EB about 85.5 % at highest conversion of BZ was obtained after 1 h of reaction on stream at 450 °C. A decrease in the temperature to 300 °C (with 1:1 mol ratio) caused the selectivity of EB to decrease to 73.0 %. EB and DEBs yields were found to increase with increasing the reaction temperature and decreasing the mole ratio of BZ to E. The conversion of BZ appeared to be depending strongly on mole ratio of BZ to E at a given temperature. The study has shown that the BXE ALKCAT zeolite is active as a catalyst for the alkylation reaction and selective to EB compared with other zeolite catalysts.

Surface properties of pillared acid-activated bentonite as catalyst for selective production of linear alkylbenzene

Acid-activated and pillared montmorillonite were prepared as novel catalysts for alkylation of benzene with 1-decene for production of linear alkylbenzene. The catalysts were characterized by X-ray diffraction, FT-IR spectroscopy, N2 adsorption isotherms, temperature programmed desorption of NH3, scanning electron microscopy and elemental and thermal analysis techniques. It was found that acid-activation of clays prior to pillaring increased the porosity, total specific surface area, total pore volume and surface acidity of the catalysts. Optimization of the reaction conditions was performed by varying catalyst concentration (0.25–1.75wt%), reactants ratio (benzene to 1-decene of 8.75, 12 and 15) and temperature (115–145°C) in a batch slurry reactor. Under optimized conditions more than 98% conversion of 1-decene, and complete selectivity for monoalkylbenzenes were achieved.

A novel catalyst for alkylation of benzene

Abstract In this research, acid-activated and pillared montmorillonite were prepared as catalysts for alkylation of benzene with 1-decene for production of linear alkyl bebzene (LAB). The catalysts were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, temperature programmed desorption (TPD) of NH3 and elemental and thermal analysis techniques. The reaction conditions were optimized by varying catalyst concentration, reactants ratio and temperature in a batch-slurry reactor. It was found that acid-activation increased the porosity and surface acidity of the catalysts. Pillaring of the sample improved the surface area, micro-mesoporosity and acidity. Under optimized conditions more than 98% conversion of 1-decene was observed. All products were LABs and no major side reaction was observed.

Benzylation of benzene over sulfated zirconia supported in MCM-41 using a single source precursor

An array of highly active, thermally stable solid acid catalysts is reported by loading different weight fractions of sulfated zirconia on mesoporous MCM-41. Different weight fractions were used to optimize the sulfated zirconia content for active and selective catalysts in alkylation of benzene with benzyl ether. The supported catalysts were prepared by impregnation of an aqueous solution of the zirconium acetate sulfonate single-source precursor into the mesoporous support. The catalytic activity of the catalysts was stable with time on stream for all catalysts examined under the reaction conditions employed. The benzene to benzyl ether mole ratio was varied from 0.1 : 1 to 20 : 1. Benzyl ether conversion was found to increase with reaction temperature and catalyst loading, while diphenyl methane selectivity was observed to increase with increasing feed mole ratio. The used regenerated catalysts completely retained its activity after the first and second regeneration.

A Study on the Coke Behaviors During Alkylation of Benzene with Ethanol Over Different HZSM-5 Catalysts

Four different kinds of HZSM-5 zeolites with different acid properties and crystal size were used as catalysts in alkylation of benzene with ethanol to produce ethylbenzene and the coke behaviors were studied. The catalysts were characterized by X-ray diffraction (XRD), Brunacr-Emmett-Teller (BET), scanning electron microscopy (SEM), wet chemical analysis, NH3-temperature programmed desorption (TPD), and Py-infrared (IR). The coke amount was measured by thermal gravity (TG) and the nature of the coke deposition was characterized by ultraviolet-visible (UV-Vis) and C/H analysis. The results showed that besides acid property, the crystal size could also affect the catalytic performance, coke content, and the nature of the coke deposition. The effect of reaction conditions including temperature, weight hourly space velocity, and time on stream on the catalytic performance and coke behaviors were also discussed over S-4.

SYNTHESIS OF ZSM-5 FROM MODIFIED CLINOPTILOLITE AND ITS CATALYTIC ACTIVITY IN ALKYLATION OF BENZENE TO ETHYLBENZENE

ZSM-5 catalysts were prepared by utilizing clinoptilolite found in Western Anatolia in abundant amounts as a type of natural zeolite. Hydrothermal reaction was conducted with HCl-treated clinoptilolite at 180°C. After characterizing the solid products obtained by this reaction as ZSM-5 by means of XRD, IR, TGA, surface area analyzer, and chemical analysis they were tested as catalysts in benzene alkylation reaction with ethylene leading to ethylbenzene. Catalytic performance of samples prepared in this study was investigated for benzene conversion, ethylbenzene yield, and selectivity. It was found that ZSM-5(A) sample showed performance similar to that of the reference sample (ZSM-5(C)) synthesized by using patented literature information in terms of benzene conversion. When the reaction temperature was increased from 400° to 425°C ethylbenzene yield and selectivity results of ZSM-5(A) sample were improved but coke formation increased. Catalyst test results indicated the possibility of using clinoptilolite as a raw material in the synthesis of ZSM-5 catalyst for alkylation of benzene with ethylene reaction.

Metal ions exchanged montmorillonite as catalyst for alkylation of benzene with 1-dodecene

About 8.5% of benzene was alkylated with 1-dodecene in the presence of Na+-montmorillonite. When the reaction was carried out with montmorillonite exchanged with Mn2+, Cu2+, Ni2+, Zn2+ and Fe2+ ions as catalyst (M2+/mont.), 91 to 95% of 1-dodecene was remarkably converted to a mixture of linear monoalkylbenzenes.

Discovery of a new catalytically active and selective zeolite (ITQ-30) by high-throughput synthesis techniques

By applying a sequential design of experiments, high-throughput syntheses, and X-ray diffraction and data-mining techniques, it has been possible to synthesize a new zeolite (ITQ-30) within a wide range of Si/Al ratios ( 10 – ∞ ). Structurally, ITQ-30 belongs to the MWW family, with disordered layers as MCM-56. Its large external surface area makes this zeolite an active and selective catalyst for alkylation of benzene with propylene.

Bmim]Cl/[FeCl 3] Ionic Liquid as Catalyst for Alkylation of Benzene with 1-Octadecene

The study on the catalysis of ionic liquids for alkylation of benzene with 1-octadecene to synthesize LAB (linear alkylbenzenes) was performed. The results showed that the most important factor that governed the conversion of olefin and selectivity of LAB was reaction temperature. Moreover, the effects of different ionic liquids and molar ratio of benzene to 1-octadecene on the conversion and selectivity were obviously in different degrees. The reaction temperature, molar ratio of benzene to 1-octadecene and the amount of catalyst were lower, compared with the traditional reaction technologies. The experimental results demonstrated that the ionic liquid had higher activity at 30°C, with over 98% selectivity of monoalkylbenzene and 100% conversion of the olefin at the molar ratio 0.08 of FeCl 3 in ionic liquid to 1-octadecene and 10 for benzene to 1-octadecene.

Gallium-containing mesoporous silicas as a catalyst for alkylation of benzene and other aromatics by benzyl chloride

The benzylation of benzene and substituted benzenes reaction employing benzyl chloride as the alkylating agent over a series of gallium-containing mesoporous silicas with different Ga contents has been investigated. These materials (Ga-HMS- n) have been characterized by chemical analysis, BET and XRD. The mesoporous gallium-containing materials showed both high activity and high selectivity for benzylation of benzene. The activity of these catalysts for the benzylation of different aromatic compounds is in the following order: benzene > toluene > p-xylene > anisole. Kinetics of the benzene benzylation over these catalysts have also been investigated.