Liquid Phase Alkylation Research Articles

Green and stable synthesis of MCM-56 zeolite by using choline chloride as template

It is desirable to develop eco-friendly structure-directing agents as an alternative to the highly toxic templates during the synthesis process of many zeolites. In this work, a MWW type zeolite (denoted as CC-MCM-56) was stably synthesized with ITQ-1 seed assistance by using a green and nuisance-less choline chloride (CC) as organic structure-directing agents instead of the conventional toxic (HMI) template. The CC-MCM-56 zeolite exhibited similar physicochemical properties to the conventional MCM-56 (HMI), including acid properties, high specific surface area, especially high external specific surface area and mesoporous volume, which performed an excellent result in the liquid-phase alkylation reaction of benzene with long-chain olefins. Our findings reveal that the synergistic effect of ITQ-1 seed and CC molecule enable a longer and more stable crystallization period during the synthesis process of MCM-56 zeolite. The SAXS result coupled with other techniques indicate that ITQ-1 seed is firstly dissolved to form more structural units which could interact with CC molecules, making more CC molecules attached to the surface half cup of the MWW lamellae and promoting the stable synthesis of CC-MCM-56 zeolite with thinner-layer structure. Finally, the synthesized CC-MCM-56 zeolite showed high reactivity and the conversion of 1-hexane and 1-dodecene achieved 90.5% and 90.6% respectively.

Case study on 4-Isopropyl-ortho-xylene production

We have experimentally studied the alkylation reaction of o-xylene with propylene under kinetic control conditions followed by realkylation under thermodynamic control conditions. The paper provides an analysis of the alkylation reaction products obtained under kinetic control as well as kinetic analysis and thermodynamic analysis of the overalkylation process. The authors have considered the methyl group migration reactions during overalkylation and have given kinetic analyses of these reactions. We found that the optimal method for the preparation of 4 isopropyl-o-xylene is to conduct the process in two stages. The first one is a liquid-phase alkylation of o-xylene under kinetic control at 353 K. The second stage is liquid-phase realkylation of the obtained alkylation reaction mass until reaching thermodynamic equilibrium at a temperature range of 303-353 K under certain conditions. These conditions should ensure minimal migration of methyl groups, i.e. with minimum contact time and alkyl-/aryl- < 0.5 ratio in the reaction products.

Получение 4-изопропил-орто-ксилола

We have experimentally studied the alkylation reaction of o-xylene with propylene under kinetic control conditions followed by realkylation under thermodynamic control conditions. The paper provides an analysis of the alkylation reaction products obtained under kinetic control as well as kinetic analysis and thermodynamic analysis of the overalkylation process. The authors have considered the methyl group migration reactions during overalkylation and have given kinetic analyses of these reactions. We found that the optimal method for the preparation of 4 isopropyl-o-xylene is to conduct the process in two stages. The first one is a liquid-phase alkylation of o-xylene under kinetic control at 353 K. The second stage is liquid-phase realkylation of the obtained alkylation reaction mass until reaching thermodynamic equilibrium at a temperature range of 303-353 K under certain conditions. These conditions should ensure minimal migration of methyl groups, i.e. with minimum contact time and alkyl-/aryl- < 0.5 ratio in the reaction products.

Continuous liquid-phase alkylation of lignocellulose-derived phenolics and cyclopentanol under large space velocity for efficient synthesis of high-performance biofuel

It is significant to efficiently and feasibly produce high-performance jet fuel from renewable biomass. We reported here that lignin-derived phenolics can be alkylated by cellulose-derived cyclopentanol in a continuous-flow fixed-bed reactor packed with HUSY zeolite without the use of solvents. Under nitrogen pressure, the liquid-phase reaction was achieved. Among the investigated zeolites with different structures and SiO2/Al2O3, HUSY-150 exhibited excellent catalytic performance and stability. By adjusting reaction conditions, almost complete conversion of cyclopentanol was achieved, as well as high phenol conversion (∼70 %), and high polycyclic product selectivity (>95 %) over HUSY-150. Afterwards, we extended the range of feedstock from phenol to other phenolics (guaiacol, 2,6-dimethoxyphenol, and lignin oil surrogates), and even at a high LHSV (liquid hourly space velocity) of 36 mL/(gcat·h), HUSY-150 maintained robust catalytic activity. This study demonstrates a feasible and effective method for producing high-performance jet fuel blends using lignocellulose-derived compounds.

Principles of creating a digital twin prototype for the process of alkylation of benzene with propylene based on a neural network

Objectives. To identify the principles of creating digital twins of an operating technological unit along the example of the process of liquid-phase alkylation of benzene with propylene, and to establish the sequence of stages of formation of a digital twin, which can be applied to optimize oil and gas chemical production.Methods. The chemical and technological system consisting of reactor, mixer, heat exchangers, separator, rectification columns, and pump is considered as a complex high-level system. Data was acquired in order to describe the functioning of the isopropylbenzene production unit. The main parameters of the process were calculated by simulation modeling using UniSim® Design software. A neural network model was developed and trained. The influence of various factors of the reaction process of alkylation, separation of reaction products, and evaluation of economic factors providing market interest of the industrial process was also considered. The adequacy of calculations was determined by statistics methods. A microcontroller prototype of the process was created.Results. A predictive neural network model and its creation algorithm for the process of benzene alkylation was developed. This model can be loaded into a microcontroller to allow for real-time determination of the economic efficiency of plant operation and automated optimization depending on the following factors: composition of incoming raw materials; the technological mode of the plant; the temperature mode of the process; and the pressure in the reactor.Conclusions. The model of a complex chemicotechnological system of cumene production, created and calibrated on the basis of long-term industrial data and the results of calculations of the output parameters, enables the parameters of the technological process of alkylation to be calculated (yield of reaction products, energy costs, conditional profit at the output of finished products). During the development of a hardware-software prototype, adapted to the operation of the real plant, the principles and stages of creating a digital twin of the operating systems of chemical technology industries were identified and formulated.

Effect of Binder Type on MWW-Based Catalysts for the Liquid-Phase Alkylation Reaction of Benzene with Ethylene

Effect of Binder Type on MWW-Based Catalysts for the Liquid-Phase Alkylation Reaction of Benzene with Ethylene

Pluronic F127-assisted partial decomposition of ammonium phosphomolybdate and its application as an efficient and recyclable catalyst for the alkylation of toluene with benzyl alcohol

The thermal decomposition of ammonium phosphomolybdate was adjusted by F127 to obtain an efficient and recyclable catalyst for liquid-phase alkylation.

Kinetic modeling of liquid phase catalytic alkylation of guaiacol with cyclohexene

The kinetics of the liquid-phase alkylation of guaiacol (G) with cyclohexene (CH) over Amberlyst 36 resin was studied using Langmuir–Hinshelwood–Hougen–Watson (LHHW) heterogeneous kinetic models. Catalytic tests were performed in a batch reactor, in solvent-less conditions, at 363 K, 1 bar, 600 RPM, using a G:CH molar ratio equal to 5 with a total volume of 30 ml and 1.5 g of solid catalyst. The alkylation of G with CH formed cyclohexyl-2-methoxyphenylether (CHMPE) by O-alkylation and cyclohexyl-2-methoxyphenol isomers (CHMP) by C-alkylation. Furthermore, CHMPE isomerizated into CHMP. A negligible amount of cyclohexylcyclohexene (CHC) was observed by dimerization of CH. Among these products, CHMP are important intermediaries for the production of resins, antioxidants, drugs, polymeric additives, agrochemicals, etc.Several LHHW kinetic models, varying the rate limiting step of reactions, were proposed in order to elucidate a reaction mechanism. The fitting of experimental data was performed consecutively by: (1) a stochastic optimization method and (2) by nonlinear regression, using the Levenberg–Marquardt algorithm, reducing the probability of reaching local minima in the objective function. The selected kinetic model considers that: (a) the rate limiting step for both the O-alkylation and C-alkylation is the surface chemical reaction between adsorbed G and adsorbed CH; (b) the adsorption of the O-alkylated products is the rate limiting step for the isomerization into C-alkylated products. Finally, this kinetic model that fits experimental data appreciably well from both physical and statistical point of view, suggests that CH adsorbs stronger than G over Amberlyst 36 catalyst.

Hydrodynamic simulation of reactor flows in liquid phase alkylation

Hydrodynamic simulation of reactor flows in liquid phase alkylation

Synthesis of Modified Catalyst for Liquid Phase Alkylation of Benzene with Ethylene

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.

Mathematical Modeling of Liquid-Phase Alkylation of Benzene with Ethylene Considering the Process Unsteadiness

Ethylbenzene is a key intermediate in the manufacture of styrene that is an important industrial monomer. Ethylbenzene is produced by benzene alkylation using either gas-phase or liquid-phase metho...

Study by NMR of Liquid-Phase Alkylation of Toluene with Hex-1-ene: Effect of Catalyst on Selectivity

In this work, the selectivity of different solid catalysts in the alkylation reaction of toluene with hex-1-ene has been studied in order to maximize mono-alkylated products. The reaction has been carried out in a fixed-bed reactor, at 120°C. An industrial alkylation catalyst has been used as a reference along with three commercial acid zeolites with difference structures (faujasite, mordenite and beta). All of catalysts achieved total conversion. Mono-alkyltoluenes selectivity was higher than 95% in all cases and formation of di-alkyltoluenes was less than 4.5%. The main products, mono-alkyltoluenes, were identified by Nuclear Magnetic Resonance spectroscopy. This work analyses the effect of physicochemical and structural properties of solid catalysts on the selectivity to the different alkylation products.

MCM-56 stabilization synthesis using auxiliary tetraethylammounium ions: Its role to inhibit surface Si-O-Al bridged linkage and retain highly delaminated structure

MCM-56 is one important member of MWW type zeolites, which possesses an unique 2D framework structure consisting of one or two MWW monolayers. Due to its high external surface area and large external acid concentration, MCM-56 zeolite exhibits excellent potential catalytic performance in alkylation of aromatics. However, it's a transient product and momentarily convert into MCM-49 zeolite. Herein, we present a facile strategy for stable synthesis of highly delaminated MCM-56 zeolite, denoted MCM-56(D), by using the dual-template system composed of hexamethyleneimine (HMI) and tetraethylammonium hydroxide (TEAOH). The characteristics of extended stable period and higher delamination degree distinguish MCM-56(D) from traditional MCM-56. The phase stabilization period is prolonged by two days or more, which is dependent on the increase of TEAOH amount. The results indicate that HMI acts as a directing agent to promote crystallization of MWW topology, while TEAOH has been proven to be a crystallization regulator by hindering Si-O-Al bridges formation in interlayers, thus forming a highly exfoliated MCM-56(D). Compared with the traditional MCM-56, the external surface area and mesoporous volume (213.6 m2/g, 1.20 cm3/g) of MCM-56(D) increased by more than 60% and 183%, respectively, naturally possessing more accessible Brønsted acid sites favourable for bulky molecule reaction, so it shows a high conversion in cracking of 1, 3, 5-triisopropylbenzene. In the liquid-phase alkylation of benzene with ethylene, MCM-56(D) performs higher reactivity and slower deactivation than MCM-22 and MCM-49 under a WSHV (Ethylene) of 2 h−1. This dual-template method ensures MCM-56(D) a practicable catalyst for processing bulky molecules in petrochemical industry.

Development of a Catalyst and a Process for Liquid-Phase Benzene Alkylation with Ethylene and the Ethane–Ethylene Hydrocarbon Pyrolysis Fraction

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.

Superacidic Mesoporous Catalysts Containing Embedded Heteropolyacids

Superacidic mesoporous silica materials containing embedded heteropolyacids (HPAs) were synthesized by sol–gel method in acidic media. In these materials, HPAs were immobilized into the silica structure covalently. The most acidic materials were obtained at the use of Pluronic P123 as a non-ionic pore-forming agent. Ionic surfactants also formed mesoporous structures, however, their interaction with HPA reduced acidity of the products. Obtained materials were tested as heterogeneous catalysts in liquid-phase alkylation of 1,3,5-trimethylbenzene by 1-decene. The most effective catalyst demonstrated higher conversion of starting substances to long-chain isomeric alkylbenzenes as compared to the activity of zeolite HY, a well-known alkylation catalyst. No leaching of HPA from silica gel was observed after the alkylation.

Framework-Substituted Sn-MOR Zeolite Prepared by Multiple pH-Adjusting Сo-Hydrolysis As Efficient Catalyst for tert-Butylation of Toluene

A series of Sn-MOR samples with different tin species loadings were prepared via a mutiple pH‑adjusting co-hydrolysis method. Their properties were characterized by XRD, XRF, UV–Vis, FT-IR, Py-IR, N2 sorption and SEM techniques. The catalytic performance was evaluated in liquid-phase toluene alkylation with tert-butyl alcohol. The characterization results shows that compared to framework destruction of mordenite for the Sn/MOR sample with floccule prepared by ion exchange method, higher relative crystallinity and larger surface area and pore volume for Sn-MOR samples with walnut morphology can be obtained. The doping with tin species can increase the Lewis acidity and decrease the pore size resulting in both higher toluene conversion and p-tert-butyltoluene (PTBT) selectivity. The Sn-MOR(0.010) sample shows the highest catalytic performance with toluene conversion of 48.0% and PTBT selectivity of 85.6%. It shows high stability: toluene conversion of 45.3% and PTBT selectivity of 87.2% can be obtained even after 5 consecutive runs.

Clay‐Based Solid Acid Catalyst for the Alkylation of p‐Cresol with tert‐Butyl Alcohol

AbstractDealuminated montmorillonite, prepared by p‐toluenesulphonic acid (pTSA) treatment, was found to be an efficient catalyst in the liquid phase alkylation of p‐cresol (PC) with tert‐butyl alcohol (TBA) in the synthesis of 2‐tert‐butyl p‐cresol (2‐TBC). Comparative studies revealed that catalytic activity of montmorillonite clay sample treated with 0.5 M pTSA (D3‐MMT) was superior to aluminium exchanged montmorillonite (Ex‐MMT) and zeolites (beta and HZSM‐5) during alkylation reaction under microwave irradiation. Thermogravimetric analysis (TG‐DTG) showed that the deactivation of zeolites was mainly due to coke formation. Correlation studies were made for D3‐MMT catalyst between volume accessibility factor (VAF) and PC conversion. These studies suggested that mesopores and types of acidities (Brønsted, Lewis and combination of both) generated after pTSA treatment were found to play role supplementing each other in enhancing the PC conversion. The regenerated catalyst recovered from the reaction mixture under microwave heating retained its catalytic activity after three cycles under optimized conditions.

Advantages of the Microwave Tool in Organophosphorus Syntheses

The microwave (MW) technique has become an important tool also in the organophosphorus field of organic chemistry. On the one hand, otherwise reluctant reactions, such as the esterification of P-acids, may be enhanced by the effect of MW, while on the other hand, catalysts may be omitted, or catalyst systems may be simplified on MW irradiation. This later group includes the Kabachnik–Fields reactions, alkylation of active methylene-containing compounds, O-alkylations, deoxygenations, as well as the Hirao reaction. It is also the purpose of this review to elucidate the scope and limitations of the MW tool, to interpret the MW effects, and to model the distribution of local overheatings and their beneficial effect.1 Introduction2 The Esterification of Phosphinic Acids2.1 Synthetic Results2.2 Scope and Limitation of the Application of MWs2.3 Modelling the Distribution of the Local Overheatings and Predicting­ Their Effect3 The Simplification of Catalytic Systems3.1 Replacement of the Catalyst by MW Irradiation3.1.1 The Kabachnik–Fields Reaction3.1.2 Solid–Liquid Phase Alkylation of Active Methylene-Containing Compounds3.1.3 Solid–Liquid Phase Alkylation of Phosphinic Acids3.1.4 The Deoxygenation of Phosphine Oxides3.2 The Hirao Reaction without Added P-Ligands4 Conclusions

Effect of zeolite pore morphology on solvent-less alkylation of benzene with 1-hexene

In an attempt to convert the carcinogenic benzene which is almost restricted for its use in gasoline, alkylation reaction with olefin 1-hexene has been conducted on various zeolites. Four zeolites having different pore topology and pore size have been applied as solid acid catalysts for effective production of alkylate in a liquid phase, solvent-less low temperature reaction. The textural properties of all the four zeolites (ZSM-5, MOR, BEA, HY) have been characterized for crystal morphology by TEM, crystal structure by XRD and FTIR, BET for surface area, N2 sorption for porosity and TPD for acidity. Among the zeolite, BEA possessed high surface area (600.61 m2/g) and enhanced meso pores volume (0.3956 cm3/g) as compared to other zeolite samples. The performance of BEA was also observed to be superior in the liquid phase alkylation of benzene with 1-hexene in a batch reactor under autogenous pressure without using any solvent. At the optimum reaction conditions, the benzene conversion was 86.6 wt% and 3-Phenylhexane, 2-Phenylhexane yield were about 47.9 wt% and 38.7 wt% respectively on this catalyst. The BEA also exhibited longer time-on-stream and reusability performance, thus offers an attractive route for converting benzene into valuable (3-Phenylhexane, 2-Phenylhexane) alkylate product useful for the manufacturing of fine chemicals, dyestuff, detergents and scents.

Adsorption and catalytic properties of sulfated aluminum oxide modified with cobalt ions

The adsorption properties of sulfated aluminum oxide (9% SO 4 2- /γ-Al2O3) and a cobalt-containing composite (0.5%Сo/SO 4 2- /γ-Al2O3) based on it are studied via dynamic sorption. The adsorption isotherms of such test adsorbates as n-hydrocarbons (C6–C8), benzene, ethylbenzene, chloroform, and diethyl ether are measured, and their isosteric heats of adsorption are calculated. It is shown that the surface sulfation of aluminum oxide substantially improves its electron-accepting properties, and so the catalytic activity of SO 4 2- /γ-Al2O3 in the liquid-phase alkylation of benzene with octene-1 at temperatures of 25–120°C is one order of magnitude higher than for the initial aluminum oxide. It is established that additional modification of sulfated aluminum oxide with cobalt ions increases the activity of this catalyst by 2–4 times. It is shown that adsorption sites capable of strong specific adsorption with both donating (aromatics, diethyl ether chemosorption) and accepting molecules (chloroform) form on the surface of sulfated γ-Al2O3 promoted by cobalt salt.