Dehydration Of Tert-butyl Alcohol Research Articles

Comprehensive Approach toward Dehydration of tert-Butyl Alcohol by Extractive Distillation: Entrainer Selection, Thermodynamic Modeling and Process Optimization

Recently, tert-butyl alcohol (TBA) has emerged as a commercially competent reagent for biofuel production, but forms a minimum boiling azeotrope with water which restricts its applicability. This paper presents a comprehensive methodology for the dehydration of TBA by extractive distillation (ED). In entrainer selection, glycolic and ionic liquids were investigated followed by VLE measurements and thermodynamic modeling. On the basis of evaluated results, pseudobinary, isovolatility and equivolatility curves have been explored to rank accurately the selected entrainers. Triethylene glycol (TEG) and 1-ethyl-3-methylimidazolium chloride [emim][Cl] emerged as the most appropriate entrainer. Finally, the process design and optimization was carried out with the minimization of total annualized cost (TAC) as the objective function. The process economics demonstrated a notable reduction of 13.9% in the TAC for [emim][Cl] as compared to TEG as an entrainer for obtaining anhydrous TBA, thereby justifying the use o...

Isobaric Phase Equilibrium of tert-Butyl Alcohol + Glycerol at Local and Subatmospheric Pressures, Volumetric Properties, and Molar Refractivity from 303.15 to 333.15 K of tert-Butyl Alcohol + Glycerol, tert-Butyl Alcohol + Water, and Water + Glycerol Binary Systems

Isobaric vapor–liquid equilibrium for the binary system of tert-butyl alcohol (TBA) + glycerol were obtained at local atmospheric pressure of 95.9 kPa and subatmospheric pressures of 66.6 and 79.9 kPa over the entire composition range using a modified Othmer-type ebulliometer. Wilson and NRTL models were used for correlating the experimental data. The results suggest that the NRTL model represented the experimental data better with lower RMSD and AAD values. Furthermore, at local atmospheric pressure of 95.9 kPa, the densities and refractive indices for the three binary systems TBA + glycerol, TBA + water, and water + glycerol involved in the dehydration of TBA by extractive distillation were measured over the entire composition range from 303.15 to 333.15 K. The volumetric properties in terms of excess molar volume, partial molar volume, and isobaric thermal expansivities as well as molar refractivity were evaluated and analyzed for the three different binary systems. A Redlich–Kister polynomial was used...

ChemInform Abstract: Kinetics of Liquid Phase Synthesis of Methyl tert-Butyl Ether from tert-Butyl Alcohol and Methanol Catalyzed by Ion Exchange Resin

Synthesis of methyl tert-butyl ether (abbreviated as MTBE) from methanol (MeOH) and tert-butyl alcohol (TBA) in the liquid phase was studied by using Amberlyst 15 in the H+ form as an acid catalyst. Experiments were carried out in a stirred batch reactor at different temperatures (313, 318, and 323 K) under atmospheric pressure. It was found that catalyst sizes and rotation speeds had no significant effects on reaction rates. Mechanism studies showed that three reactions took place simultaneously. It was also found that dehydration of TBA could not be neglected. The experimental concentration profiles with time could be simulated well by simple kinetics. Finally, rate constants could be expressed by Arrhenius equations. © 1993 John Wiley & Sons, Inc.

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.

Kinetics of liquid phase synthesis of ethyl tert‐butyl ether from tert‐butyl alcohol and ethanol catalyzed by β‐zeolite supported on monolith

AbstractThis paper compared the performance of β‐zeolite and Amberlyst‐15 catalysts on a liquid phase synthesis of ethyl tert‐butyl ether (ETBE) from ethanol (EtOH) and tert‐butyl alcohol (TBA) β‐Zeolite was synthesized and deposited on monolith support. Its structure was confirmed by an XRD measurement and its composition was analyzed by an XRF measurement. It was found that even though the catalytic activity of β‐zeolite was lower than that of Amberlyst‐15, the selectivity of ETBE was much higher than that of Amberlyst‐15, resulting in almost the same level of ETBE yield. The dehydration of TBA to isobutene (IB) was the major side reaction. The kinetic study of the reaction catalyzed by β‐zeolite supported on monolith was carried out by using a semibatch reactor. The effect of external mass transfer was investigated by varying stirring speeds. The activity‐based rate expressions were developed taking into account of water inhibition. Three temperature levels of 323, 333, and 343 K were performed in the study to obtain the parameters in the Arrhenius's equation and the Van't Hoff's equation. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 292–299, 2002

Reactive distillation with KATAPAK®

KATAPAK-SP and -S are structured catalytic packings for reactive distillation or gas–liquid reactors available from laboratory to industrial scale. Applying the KATAPAK-SP concept, the ratio of catalyst volume fraction to separation efficiency can be varied over a wide range, therefore the design of a reactive distillation column can be further optimized to fit each reaction system best.Pressure drop, separation efficiency, dynamic liquid hold-up and residence time distribution have been investigated for KATAPAK-SP in a diameter of 250mm. Results for different gas and liquid loads are presented. The findings are compared with results for the structured laboratory scale packing KATAPAK-S and the industrial scale packing KATAPAK-S 170.Y.The dehydration of tert-butyl alcohol was selected as a sample reaction to illustrate the influence of different catalytic structures on the performance of the reactive distillation column. The setups are compared with respect to dimensions and economics.

Kinetic study on the dehydration oftert-butyl alcohol catalyzed by ion exchange resins

The dehydration of tert-butyl alcohol (TBA) in the liquid phase was studied by using an ion exchange resin, Amberlyst 15 (A15) in the H+ form. Experiments were carried out both in a semi-batch reactor and in a continuous stirred tank reactor (CSTR) with wet or dry resins. The results with the dry resin in the semi-batch reactor were different from those with the wet resin due to the swelling of resin in the presence of water. However, the results in CSTR agreed well with those in the semi-batch reactor using the wet resin. A rate equation that considered the inhibition of water was formulated. The experimental results agreed well with the calculated ones. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 854–859, 1999

Reactive Distillation for Synthesizing Ethyl tert-Butyl Ether from Low-Grade Alcohol Catalyzed by Potassium Hydrogen Sulfate

Synthesis of ethyl tert-butyl ether (ETBE) from the reaction between ethanol (EtOH) and tert-butyl alcohol (TBA) in the presence of different acid catalysts (KHSO4, NaHSO4, H2SO4, and Amberlyst 15) was investigated at low alcohol grade (mixture of 80 mol % water). Potassium hydrogen sulfate (KHSO4) showed the highest selectivity among the tested catalysts. Other catalysts caused the dehydration of TBA into water (H2O) and isobutene (IB). In the top of the reactive distillation column with total reflux, the condensate was split into two layers. The upper layer contained ETBE with a more than 60 mole fraction.

Kinetics of liquid‐phase synthesis of ethyl tert‐butyl ether from tert‐butyl alcohol and ethanol catalyzed by ion exchange resin and heteropoly acid

AbstractSynthesis of ethyl tert‐butyl ether (ETBE) from ethanol (EtOH) and tert‐butyl alcohol (TBA) in the liquid phase was studied by using ion exchange resin, Amberlyst 15 (A15) in the H+ form and heteropoly acid, H0.5Cs3.5SiW12O40(HPA). Experiments were carried out in a stirred batch reactor with different temperatures under atmospheric pressure. It was found that water will inhibit the reaction rates greatly and the dehydration of TBA could not be neglected in this study.A kinetics model which considered the inhibition of water and the decrease of volume was proposed. The experimental results agreed well with the model. © 1995 John Wiley & Sons, Inc.

Kinetics of liquid phase synthesis of methyl tert‐butyl ether from tert‐butyl alcohol and methanol catalyzed by ion exchange resin

AbstractSynthesis of methyl tert‐butyl ether (abbreviated as MTBE) from methanol (MeOH) and tert‐butyl alcohol (TBA) in the liquid phase was studied by using Amberlyst 15 in the H+ form as an acid catalyst. Experiments were carried out in a stirred batch reactor at different temperatures (313, 318, and 323 K) under atmospheric pressure.It was found that catalyst sizes and rotation speeds had no significant effects on reaction rates. Mechanism studies showed that three reactions took place simultaneously. It was also found that dehydration of TBA could not be neglected. The experimental concentration profiles with time could be simulated well by simple kinetics. Finally, rate constants could be expressed by Arrhenius equations. © 1993 John Wiley & Sons, Inc.

Generation of acid sites by SiO 2 deposition on groups IVB metal oxides

An ultra thin silica layer was prepared by chemical vapor deposition of Si(OCH 3) 4 onto titania and zirconia. The relationship between surface structure and acidity was studied by measurement of coverage, IR spectroscopy of probe molecules, and test reactions. Silica was deposited to form a 1 : 1 complex with the oxide cation (-MSi-), until more than 90% of monolayer coverage was obtained. The silica overlayer showed weak Brønsted acidity only sufficient to catalyze the isomerization of 1-butene and the dehydration of tert-butyl alcohol. The acidity could not be correlated with the difference in coordination number or valence of cations but seemed to correlate with the interaction between silica and metal oxide.

Thin silica layer on alumina: evidence of the acidity in the monolayer

A thin silica layer on alumina was readily prepared by chemical vapor deposition of silicon methoxide; the structure of deposit silica and its relationship with the surface acidity were studied by characterization and test reactions. A silica monolayer was formed from the beginning of deposition until it covered the alumina surface almost completely. The silica monolayer on alumina possessed the Bronsted acid sites active for the isomerization of 1-butene and the dehydration of tert-butyl alcohol but inactive for the cumene cracking

Determination of the surface acidity of solid catalysts

A novel method has been developed for determining the surface acidity of white, as well as deeply colored porous solids. The method, which was tested on Al2O3, SiO2−MgO−Al2O3 and Fe2O3 catalysts, is based on the adsorption of pyridine or benzylamine on acidic sites and subsequent displacement of the adsorbed bases by n-butylamine. A linear correlation was found between the concentration of acidic sites on Al2O3 and Fe2O3 catalysts and their activity in the dehydration oftert-butyl alcohol.