Synthesis Of Ethyl Tert-butyl Ether Research Articles

Crucial Role of Weak Acid Sites for Catalytic Performance of Zeolites in Ethyl tert-butyl Ether Synthesis

Catalytic activity of different zeolites: H,NH4-form of mordenite-containing rock (H-CMK) and H-Beta with a Si/Al ratio of 15–407 (H-ВЕА) in ethyl tert-butyl ether (ETBE) synthesis in a packed-bed flow reactor at 80–180°C and 1 MPa has been studied. Acid characteristics of zeolites were determined by stepwise (Quasi-Equilibrium) ammonia thermodesorption. Three types of acid sites of different strength has been found, which is marked as weak (ENH3 = 60–75 kJ/mol), medium (ENH3 = 86–123 kJ/mol), and strong (ENH3 = 112–145 kJ/mol). The correlation between ETBE productivity and the concentration of weak acid sites has been found. Thereby, it was established that weak acid sites of zeolites are the active sites in ETBE synthesis.

Effect of Acid Site Localization in Sulfonic Resin Amberlyst 15 on its Catalytic Properties in Ethyl tert-butyl Ether Synthesis

The role of the localization of acid sites in macroporous sulfonic resin Amberlyst 15 in the synthesis of ethyl tert-butyl ether was investigated. By partial blockage of the acid sites by Na+ cations it was established that internal acid sites are primarily active in the reaction while a side reaction with the formation of tert-butanol takes place at the external acid sites.

Ethyl tert-butyl ether synthesis using carbon catalysts from lignocellulose

Porous structure, surface chemistry and catalytic properties of carbon catalysts with various acid groups in ethyl tert-butyl ether synthesis were studied. Carbon catalysts were obtained by phospho...

In English

We present a study on physical-chemical properties of hybrid inorganic-organic acid materials and their catalytic performance in ethyl tert-butyl ether synthesis under both atmospheric and elevated pressure. Such materials are compositions of acid styrene-divinylbenzene copolymer and silica with various (1.5–9.2 wt.%) polymer loadings (loaded resins LR). We have found that LR has better thermal stability compared to that of commercial sulfonic resins. Acidic properties of LR show that the acidity of polymer phase decreases with increasing of polymer loading. Catalytic tests show that under atmospheric pressure ethyl tert-butyl ether synthesis requires a higher acid capacity of LR than that under elevated pressure and proceeds with 100% of selectivity. Under pressure the side reaction of tert-butanol formation occurs and LR samples with higher polymer content (≥ 6.9 wt.%) possess lower conversion but higher selectivity compared to LR with polymer content below 6.9 wt.%.

Residue Curve Map Determination and Synthesis of Ethyl tert-Butyl Ether via Reactive Distillation

Ethyl tert-Butyl Ether (ETBE) is considered next generation fuel additive and its use is growing in the world as octane booster as well as oxygenate for gasoline fuels. This study deals with the experimental residue curve map (RCM) determination for ETBE synthesis using an ion exchange resin catalyst, at wide range of molar feed ratio of reactants. RCM experiments revealed the existence of a quaternary reactive azeotrope at 349 K. Molar feed ratio of 1:1.5 (TBA:EtOH) was found optimum. Results of batch kinetics and RCM studies were used in an experimental reactive distillation column for ETBE synthesis using ion exchange resin catalyst CT-145H. The column was also simulated at optimum operating conditions using CHEMCAD® as simulation tool. The experimental and simulation results were then compared.

Effect of the Morphology of Sulfo Cation Exchangers on their Catalytic Properties in the Preparation of Ethyl tert-Butyl Ether

It was shown that the morphology of sulfo cationic exchange catalysts described by fractal geometry determines their characteristics in the heterogeneous catalytic synthesis of ethyl tert-butyl ether. It was established that catalysts with partial coverage of the support by the sulfo cation exchanger have higher selectivity and greater productivity in the active phase than catalysts with more than monolayer coverage.

Mesoporous Organosilicas with Arylsulfonic Acid Bridging Groups in the Alkylation of Isobutylene by Ethanol

Sulfonation of mesoporous organosilicas with diethylxylene bridging groups using chlorosulfonic acid gave mesoporous silicas with arylsulfonic acid bridging groups. TPD-MS was used to confirm the structure and characterize the thermal stability of the organic groups of the starting and sulfonated samples. The catalytic activity of mesoporous silicas with arylsulfonic acid bridging groups in the synthesis of ethyl tert-butyl ether is higher than for model samples (MCM-41 mesoporous molecular sieves and silica gel with anchored alkylsulfonic acid groups as well as SiO2/Nafion nanocomposite) and is similar to the activity of industrial catalysts such as Amberlyst-15.

Optimizing the Synthesis of Ethyl tert-Butyl Ether in Continuous Catalytic Distillation Column Using New Ion Exchange Resin Catalyst

Liquid phase synthesis of one of the important fuel oxygenate, ethyl tert-butyl ether (ETBE), from ethanol and tert-butyl alcohol (TBA) has been studied in catalytic distillation column (CDC) using ion exchange resin catalyst CT-145H. A packed CDC of 1.2 m height and 50 mm diameter with indigenously developed reactive section packing was used to generate experimental data. Effect of different key variables on product purity in distillate, was investigated to find the optimum operating conditions for ETBE synthesis. The optimum conditions for 0.2 kg·s−1 of ethanol feed were found: reboiler duty of 375 W, molar feed ratio of 1 : 1.3 of reactants, and reflux ratio of 7. Concentration profiles for each component along each column section at optimum conditions were also drawn. Neither output nor input multiplicity was observed at experimental conditions.

Fractality and activity of acid catalysts in the liquid-phase synthesis of ethyl tert-butyl ether

A study was carried out on the synthesis of ethyl tert-butyl ether from ethanol and 2-methylpropene on silica gel samples modified by the addition of ZrO2 and Al2O3. A decrease in the turnover frequency (TOF) of the reaction is observed with increasing acidity of surface of the modified silica gels. A relationship was found between the TOF of the reaction and the fractal dimension of the catalyst. The TOF of the reaction decreases with increasing fractal dimension of the catalyst.

Preparation of hybrid organo-inorganic catalysts based on MSM-41 mesoporous molecular sieves and their properties in synthesis of ethyl tert-butyl ether

A series of sulfoorganosilica (vinyl-containing) catalysts based on MSM-41 mesoporous molecular sieves were prepared by template synthesis. The structure and properties of these catalysts and their catalytic characteristics in synthesis of ethyl tert-butyl ether were examined.

Acid properties of phosphoric acid activated carbons and their catalytic behavior in ethyl-tert-butyl ether synthesis

Carbon catalysts were prepared by phosphoric acid activation of styrene–divinylbenzene copolymer followed by liquid phase oxidation with nitric acid. Their surface properties were modified by heat treatment at 300–600 °C in an argon atmosphere, and their acid properties were characterized by quasi-equilibrium temperature desorption of ammonia and by acid–base titration. The pore structure was characterized by nitrogen adsorption at −196 °C. Their catalytic activity in the synthesis of ethyl-tert-butyl ether (ETBE) from isobutene and ethanol was investigated. It has been shown that the carbon catalysts are active and selective in ETBE synthesis. The main factor determining the catalytic activity of carbon catalysts is the total number of acid surface sites. A linear correlation between total amount of surface sites and catalytic activity was found.

Liquid-phase synthesis of ethyl tert-butyl ether over acid cation-exchange inorganic–organic resins

In this study the possibility to increase the productivity of acid cation-exchange resin catalysts active sites in ETBE synthesis was elucidated. For this purpose the inorganic–organic sulfonated cation-exchange resins with different polymer loadings (1.5–9.2 wt.%) have been synthesized. Such polymer/carrier composites as well as commercial acidic microporous gel-type ion-exchange resin KU-2-8 and macroporous Amberlyst 15 have been studied in the ETBE synthesis. Acid properties of all solids were determined by quasi-equilibrium thermogravimetry of ammonia desorption. We have found out that polymer loading and acid capacity affect oppositely on the ETBE productivity. As a result, there is no direct correspondence between the ETBE productivity of the inorganic–organic sulfonated cation-exchange resins per gram of catalyst on their acidity. However, there is a linear relation between the productivity per gram of polymeric phase and acidity. It was established that due to a better accessibility of acid sites for reactants loaded sulfonated cation-exchange resins exceeds the commercial catalysts by the site time yield values.

Oniumsilica-immobilized-Keggin acids: Acidity and catalytic activity for ethyl tert-butyl ether synthesis and acetic acid esterification with ethanol

Keggin heteropolyacids were immobilized on functionalized silica as their onium ( γ-propyl- N-pyridinium, γ-propyl- N-methyl and γ-propyl- N-butyl-imidazolium) salts. Interaction between HPA and the surface-grafted onium cations affords acid salts. In contrast to bare silica, impregnated with HPA, these materials have monoanionic dispersions of HPA on the surface and superior resistance to HPA leaching in polar media. The greatest stability of the Keggin structure and resistance to leaching were found for H 4SiW 12O 40–(SiW)-, and the lowest for H 3PMo 12O 40–(PMo)-based samples. In the two model reactions tested, the liquid-phase synthesis of ETBE and the esterification of AcOH with EtOH, these solids display good catalytic performance (activity per anion, up to 150 and 25 h −1, respectively) and relative high structural stability. Catalysts having a greater coverage of organic functions (revealed by comparing two pyridinium salts) and hydrophobic cations (by comparing two imidazolium salts) have the best performance. Amongst the heteropolyacids studied, H 4SiW 12O 40 is the most active and promising for catalyst design.

Product Distributions in Ethyl tert-Butyl Ether Synthesis over Different Solid Acid Catalysts

Vapor-phase ethyl tert-butyl ether (ETBE) synthesis was carried out in a fixed-bed flow reactor in the presence of three different kinds of heteropolyacid catalysts and four different kinds of ion-exchange resins. An activity change in the order of silicotungstic acid > tungstophosphoric acid (Dawson) > tungstophosphoric acid (Keggin) was observed with heteropolyacids and Amberlyst 15 > Lewatit K-2629 > Amberlyst 35 > Amberlyst 16 with ion-exchange resins. In ETBE synthesis over heteropolyacid catalysts, diethyl ether and ethylene (valuable petrochemical feedstocks) formation was also observed at temperatures above 368 K. DRIFTS analysis of pyridine-adsorbed samples revealed changes in acidity in accordance with activity. The significance of Bronsted acidity on the catalyst activity was illustrated. The inhibiting effect of water on ethanol adsorption and hence the catalyst activity was demonstrated by interpretation of experiments conducted using Amberlyst-15. Conversion of diluted ethanol to ETBE in the...

The Effect of Proton Hydration in Wells-Dawson and Keggin Type Heteropolyacids on their Catalytic Activity in Gas Phase ETBE Synthesis

The influence of proton hydration in Wells-Dawson H6P2W18O62 (HP2W) and Keggin H3PW12O40 (HPW) type heteropolyacids on their catalytic activity in ethyl-tert-butyl ether (ETBE) synthesis in gas phase was investigated. In the case of samples with the content of crystallisation water per one proton below 0.8 ([H2O]/[H+] 0.8 the activity was much higher for the HP2W than the HPW and maximum of both catalytic activity and ethanol sorption capacity was observed for the HP2W. The possible role of the secondary structure of the hydrates was discussed.

Synthesis of ethyl tert-butyl ether with tert-butyl alcohol and ethanol on various ion exchange resin catalysts

Heterogeneous catalytic synthesis of ETBE with tert-butyl alcohol (TBA) and ethanol (EtOH) using seven ion exchange resins has been studied. After characterization of catalysts, batch kinetic studies were conducted to sort out the most suitable catalyst based on TBA conversion and ETBE selectivity. Optimum operating conditions found were 343 K temperature; 1:2 feed mole ratio (TBA:EtOH), and 10% catalyst loading. Kinetic modeling for the most suitable catalyst CT-145H was done using heterogeneous and quasi-homogeneous models, but latter fit well to experimental data.

Liquid phase synthesis of ethyl- tert-butyl ether: The relationship between acid, adsorption and catalytic properties of zeolite catalysts

The role of acid centers of natural zeolites in synthesis of ethyl- tert-butyl ether (ETBE) was investigated. The method for calculation of desorption energy distribution from stepwise desorption experiment was proposed. The method allows to calculate continuous desorption energy distribution of surface sites using different probes (ammonia, ethanol, iso-butylene, etc.). The correlation between rate of ETBE synthesis and concentration of weak acid sites ( E N H 3 = 70 – 75 kJ mol −1) was found. It has been shown that during ETBE synthesis iso-butylene is activated mainly on medium and strong acid centers and forms one type of surface complex, while ethanol forms two types of adsorbed complexes. Low energy surface ethanol complexes ( E = 53–60 kJ mol −1) located on weak acid centers of zeolites were found to be active in ETBE synthesis. These complexes govern the catalytic activity of catalyst in ETBE synthesis.

Multi-fields synergy in the process of reactive distillation coupled with membrane separation

A new method for analyzing reactive distillation coupled with membrane separation system was proposed with the viewpoint of non-equilibrium thermodynamics and the phenomenological theory. The synthesis of ethyl tert-butyl ether was chosen as a model system. The synergy of multi-fields such as temperature, concentration and chemical potential in this combined process was discussed; the relationship of each vector within a field was investigated by considering both of Soret effect and Dufour effect. The equations of mass and heat fluxes were established and the coefficients for both of them were obtained with the condition of the synergy in multi-fields. It can be known from the research results that the mass and heat transfer rate were increased or decreased with the synergy of multi-fields; the direction of transfer was also changed by the effect of synergy of multi-fields. From the viewpoint of field synergy, the model of non-equilibrium stage for the reactive distillation coupled with membrane separation was developed. The model incorporated complex reaction kinetics, vapor–liquid non-idealities, distillation and pervaporation process. The rapid solution for this model can be obtained by Newton–Raphson method. Simulation results are in good agreements with the experimental results.

Simulation of Ethyl Tert-Butyl Ether Production from Tert-Butyl Alcohol and Ethanol in Reactive Distillation

Reactive distillation was applied for the synthesis of ethyl tert-butyl ether (ETBE) from a liquid-phase reaction between tert-butyl alcohol (TBA) and ethanol (EtOH) catalyzed by commercial ~-zeolite catalyst with Si/AI ratio of 55. The major side reaction of this system was the dehydration of TBA to isobutene (lB). From the present researchers' previous work, it was found that B-zeolite was superior to commercial Amberlyst-15 catalyst in reaction selectivity. The kinetic parameters for the reactions, which were determined using a semibatch reactor operated at various temperatures, were used for simulation in Aspen Plus TN program. Various operating parameters, such as heat duty, molar ratio of Hz0: EtOH, and refluxratio, were investigatedfor their effectson reactive distillation performance. Keywords: ,B-zeolite,ethyl tert-butyl ether (ETBE) synthesis, and reactive distillation.

Production of ethyltert-butyl ether fromtert-butyl alcohol and ethanol catalyzed byβ-zeolite in reactive distillation

The synthesis of ethyl tert-butyl ether (ETBE) from a liquid phase reaction between tert-butyl alcohol (TBA) and ethanol (EtOH) in reactive distillation has been studied.β-Zeolite catalysts with three compositions (Si/Al ratio=13, 36 and 55) were compared by testing the reaction in a semi-batch reactor. Although they showed almost the same performance, the one with Si/Al ratio of 55 was selected for the kinetic and reactive distillation studies because it is commercially available and present in a ready-to-use form. The kinetic parameters of the reaction determined by fitting parameters with the experimental results at temperature in the range of 343–363 K were used in an ASPEN PLUS simulator. Experimental results of the reactive distillation at a standard condition were used to validate a rigorous reactive distillation model of the ASPEN PLUS used in a simulation study. The effects of various operating parameters such as condenser temperature, feed molar flow rate, reflux ratio, heat duty and mole ratio of H2O : EtOH on the reactive distillation performance were then investigated via simulation using the ASPEN PLUS program. The results were compared between two reactive distillation columns: one packed withβ-zeolite and the other with conventional Amberlyst-15. It was found that the effect of various operating parameters for both types of catalysts follows the same trend; however, the column packed withΒ-zeolite outperforms that with Amberlyst-15 catalyst due to the higher selectivity of the catalyst.