Abstract  An industrial scale process is proposed for the synthesis of ethyl tert-butyl ether (abbreviated as ETBE) from bioethanol and tert-butyl alcohol (TBA), and simulated by using ASPEN PLUS, a sequential modular simulation software package. The IB-rich gaseous product from the first reactive distillation column is used to react with pure ethanol (EtOH) in the second reactive distillation column. The overall conversion of tert-butyl alcohol (TBA) and the overall ETBE selectivity are 98.9 and 99.9%, respectively.

Abstract  Consistent vapor-liquid equilibrium data for the binary systems ethyl 1,1-dimethylethyl ether (ETBE)+ 2,2,4-trimethylpentane and ethyl 1,1-dimethylethyl ether + octane at 94 kPa, including pure component vapor pressures of 2,2,4-trimethylpentane and octane, have been experimentally determined. The measured systems deviate slightly from ideal behavior, can be described as symmetric regular solutions and present no azeotropes. Boiling points were correlated using the Wisniak-Tamir equation.

Abstract  Six polyamideimides (PAI) were synthesized from six dianhydride monomers containing amide functions. The dianhydride monomers were obtained from the reaction of trimellitic anhydride chloride with six aromatic diamines—1,4-phenylenediamine, 2,2-bis(4-aminophenyl) propane, 4,4′-oxydianiline, 4,4′-methylenedianiline, 1,1-bis(4-aminophenyl)cyclohexane, and bis(4-aminophenyl)sulfone—by a low-temperature condensation with yields ranging from 35 to 98% depending on the monomer solubility in organic media. The monomers were characterized by Fourier transform infrared (FTIR) and 1H NMR. In accordance with a synthesis scheme implying the reaction of a macrodiisocyanate with dianhydride monomers containing amide functions, six PAIs with a highly flexible soft block (polytetramethylene glycol PTMG 650) were synthesized with inherent viscosities ranging from 0.38 to 1.3 dL/g. Their characterization by FTIR and 1H NMR fully confirmed their chemical structure. The strong physical crosslinking provided by polar hard blocks containing up to eight aromatic rings enabled the casting of PAI films that were very tough in the dry state and could withstand exposure to rather strong solvating media (e.g., ethers, alcohols, and chlorinated solvents). First experiments showed these materials could be good candidates for membrane-separation applications. They revealed interesting features for the separation of organic aprotic–protic mixtures as shown by the first results obtained for the purification of a fuel octane enhancer (ethyl-tert-butyl ether) used in the European Community. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 614–630, 2000

Abstract  Reactive distillation is a bidirectional (i.e. the process gains change sign over the operating range) and highly non-linear process. These characteristics reduce the controllability of the process and suggest that the steady state benefits of reactive distillation might not be realized with a simple control scheme. There are also insufficient degrees of freedom to satisfy the reaction and separation objectives simultaneously. An integrated control scheme is proposed here, using an ETBE column as an example, to address these problems by permitting the control objectives to be changed online in order to reflect changing economic constraints. The careful selection of controlled and manipulated variables allows this scheme to be implemented with linear controllers only. More complex control systems can be built onto the current control architecture, if required. In these cases, the current control structure will maximize the effectiveness of the advanced control alication.

Abstract  Dynamic simulation is used to understand the effect of a startup policy on the ethyl tert-butyl ether (ETBE) reactive distillation. Because input multiplicity is likely to occur in every reactive distillation, its effects on startup are investigated. The ETBE reactive distillation is presented as an example to show characteristic behaviors during startup of the ETBE column, It is found that the dynamics of the startup condition are influenced by the given startup policy. An understanding of the input multiplicity is a necessary requirement before performing the startup operation to avoid excessive energy, to achieve a stable optimum process operation.

Abstract  Methyl-tert-butylether (MTBE), ethyl-tert-butylether (ETBE) and tert-amylmethylether (TAME) are generally accepted on the market as antiknock agents (additives) and even as a feedstock of the chemical industry, but are associated with environmental dangers, including contamination of ground water. The authors present a method to remove low concentrations of these ethers with ultrasound.

Abstract  Micro-calorimetric measurements of excess molar enthalpies H-m(E) are reported for {ethyl tert-butyl ether (ETBE, ethyl 1,1-dimethylethyl ether) + n-hexane, n-heptane, or n-octane}. These H-m(E) values, together with those reported previously for tert-amyl methyl ether (TAME, 1,1-dimethylpropyl methyl ether) + n-alkane, all measured at T = 298.15 K, were used to predict (vapour + liquid) equilibria v.l.e. for (ETBE, or TAME + n-alkane) and (ETBE, or TAME + n-alkanes) at isobaric/isothermal conditions. The predictions were made using the excess Gibbs free energy model of Liebermann and Fried. The predicted v.l.e. values are in good agreement with the literature values, and are comparable to reported correlation results obtained from four activity coefficient models (Wohl, Wilson, NRTL, and UNIQUAC). (C) 2001 Academic Press.

Abstract  A review with 29 refs. covering reformulated gasolines and their oxygenated components (alcohols, ethers), production, alications and advantages of MTBE as gasoline component, MTBE toxic properties and (bio)degradability. High octane number, low partial pressure, low atmospheric reactivity and suppression of C6H6, AcH, 1,3-butadiene and VOC emissions from gasoline speak In favor of MTBE as gasoline component. Its toxicity, degradability and cancerogenicity require more studies. So far there Is no safe substitute (ETBE?) for MTBE.

Abstract  Ethanol is already used as biofuel in different countries such as Brazil, United States of America, Canada and France. Ethanol may be directly added to the gasoline or in ETBE (ethyl-tertio-butylether) form, synthesized with isobutene. In this paper, are presented different parameters which control the ethanolic fermentation and different schemes of processes using starchy vegetals (corn, wheat), sugar plants (sugar beet, sugar cane) and the lignocellulosic biomass. Some economical aspects are covered and the main characteristics of ethanol and ETBE as biofuel are summarized.

Abstract  Fuel decomposition and hydrocarbon growth processes of methyl tert-butyl ether (MTBE) and related alkyl ethers have been studied experimentally in soot-producing non-premixed flames. Temperature, Cl-C12 hydrocarbons, and major species were measured in coflowing methane/air flames whose fuel was separately doped with 5000 m of MTBE, n-butyl methyl ether (NBME), sec-butyl methyl ether (SBME), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME, =1,1-dimethylpropyl methyl ether), The consumption rates of the dopants, several simple kinetic calculations, and the dependence of the observed products on fuel composition indicate that the dominant decomposition process was unimotecular dissociation, not H-atom abstraction. The dominant dissociations were four-center elimination of alcohols for the doubly branched ethers (MTBE, ETBE, and TAME) and C-O fission for the linear ether (NBME), while four-center elimination and C-O fission were comparably important for the singly branched ether (SBME). These dissociations produced alkenes which further reacted to produce alkadienes/alkynes, alkenynes, acetylenic compounds, and aromatics, The dependence of the maximum benzene mole fractions on fuel composition was consistent with benzene formation through reactions of highly-unsaturated C3 and/or C4 hydrocarbons (C3H3, n-C4H3, C4H4, n-C4H5, etc.). (C) 2004 Wiley Periodicals, Inc.

Abstract  The objective of this contribution is to propose a mixed integer nonlinear programming (MINLP) formulation for optimal design of a catalytic distillation column based on a generic nonequilibrium (NEQ) model. The use of this NEQ model presents two main advantages: (i) the computation of tray efficiencies is entirely avoided and (ii) the geometrical parameters of the column's hardware can be optimized. The minimization of the total annualized cost is submitted to three sets of constraints: the model equations, the product specification, and the tray hydraulic equations. The solution strategy for the optimization uses a combination of simulated annealing and sequential quadratic programming. Catalytic distillation of ethyl tert-butyl ether (ETBE) is considered as an illustrative example. The results of the optimization are discussed. Pre- and postoptimal sensitivity analysis is also performed.

Abstract  One way of improving the ecological properties of gasolines is to develop effective, cheap, and environmentally clean high-octane additives. The prohibition of toxic lead-containing antiknocks led to the development of alternative compounds. As experience in using them showed, oxygen-containing additives or oxygenates were the most promising: methyl tert-butyl, ethyl tert-butyl ethers (MTBE, ETBE), methanol, and others [1].

Abstract  The technical re-conversion of MTBE process to produce ETBE was studied, using a non-equilibrium model in catalytic distillation with an UNIFAC method at steady state. The simulation was carried out in Aspen Plus, analyzing the possibility of using the actual installations of the MTBE plant as it works, to produce ETBE. The study is focused on the reactive and the catalytic distillation sections, which rule the process behavior. The analysis of azeotrope conditions revealed that the ethanol-to-isobutene molar feed ratio is the main factor affecting the equilibrium, by modifying the separation between the ETBE product and the butylenes in the catalytic column. The indirect effect of increasing the operating pressure in the reaction equilibrium, by changing the phase equilibrium temperatures increasing them also, as well as by modifying the ethanol-isobutene feed ratio at the reactive zones at a higher value, are the variables that limit the equilibrium. Consequently, a high isobutene conversion is attained. Finally, doing a comparison between the two processes, it can be confirmed that the ETBE can be produced in the same installations, obtaining an isobutene conversion of 98 weight % and an ETBE product with an overall composition of 98 weight %.

Abstract  Isobaric vapor-liquid equilibria data at 101.3 kPa were reported for the binary mixtures ethyl tert butyl ether (ETBE) + (p-xylene, m-xylene and ethylbenzene). VLE experimental data were tested for thermodynamic consistency by means of a modified Dechema test and was demonstrated to be consistent. The activity coefficients were correlated with the Margules, van Laar, UNIQUAC, NRTL, and Wilson equations. The Analytical Solution Of Groups (ASOG) model also was applied for prediction.

Abstract  Accurate vapor-liquid equilibria were measured for the ternary system ethyl 1,1 -dimethylethyl ether + n-heptane + 1-hexene using an isothermal total pressure cell. The experimental data were well correlated using Wohl expansion and Wilson, NRTL and UNIQUAC models. The system shows a slight positive deviation from the ideality. A comparison with similar ternary systems containing other ethers is also discussed in the paper. (c) 2007 Elsevier B.V. All rights reserved.

Abstract  The use of bioethanol in motor fuels was compared using 2 different percentage volumes in petrols. A direct blend of bioethanol in 5% volume of petrol and 15% volume in petrol in ethyl-tertiary-butyl-ether manufacture were assessed. The quality standards of fuel ethanol, its advantages and disadvantages in blends and the effects of higher content in petrol blends were presented. The bioethanol content higher than 5% resulted to a higher vapour pressure and excessive emission of volatile organic compounds. The permitted oxygen volume of 2.7% caused the limitation on the amount of bioethanol for petrol blends.

Abstract  The catalytic characteristics of massive and loaded sulfonic resins in the synthesis of ethyl tert-butyl ether at atmospheric and increased pressures have been compared. It has been established that massive sulfonic resins are more active than loaded resins at atmospheric pressure. At higher pressures, on the other hand, the activity and selectivity of catalysts are greater the lower the content of polymer as a result of the increased effectiveness of the acid centers.

Abstract  We have studied the fluctuations in mean indicated pressure (MIP) in a diesel engine powered by different fuels. Three alternative fuels and the regular diesel oil (RD) were tested. The alternative fuels are: (1) mixture of fatty acid methyl esters (FAME) and anhydrous ethanol (ET), (2) mixture of FAME and ethyl tertiary-butyl ether (ETBE), and (3) mixture of RD and ETBE. Using statistical and wavelet analyses, we investigated the cycle-to-cycle MIP variations for each fuel, at three engine speeds of 1200, 1600 and 2000 rpm. The results for the alternative fuels were compared with those for RD. At all three speeds, the MIP variations for the alternative fuels were found to exhibit strong periodicities of 64-256 cycles, and these periodicities persist over many engine cycles, whereas shorter-term periodicities at 2-32 cycles appeared to be intermittent. In the case of RD, the MIP variations with longer periodicities appeared only at the highest engine speed but intermittent fluctuations of 2-32 cycles are present at all three speeds. Among the four fuels considered, the MIP variations for the RD were found to be closest to the Gaussian white noise.

Abstract  To improve octane performance and reduce emissions, MTBE and to lesser degree ETBE and TAME are blended into gasolines. These oxygenates coelute with hydrocarbon components of gasoline in GC analysis. It is known that oxonium ions are formed in the electron impact mass spectrometry Of aliphatic alcohols and ethers. The base ions of t-BuOH, MTBE, ETBE, TAME, and BEE are either mit 59 or 73 ions, and fragment ions of alkanes, alkenes, and naphthenes are at mit 41, 43, 55, 57, 69, 71, 83, and 88. The maximum background m/z59 and 73 ion abundances of three diluted (1:20) gasolines which are used to determine percent oxygenates in gasoline were less than 0.04% that of the lowest analyte standard used to determine the linear regression coefficients of these ethers. The background mit 59 and 73 traces of undiluted gasoline were also studied. An ACN/gasoline partitioning cleanup technique was used to remove hydrocarbon interferences of less than 2% (v/v) oxygenated gasoline prior to identification by GC/MS.

Abstract  Ethyl tert-butyl ether (ETBE) is an alternative fuel oxygenate that can be produced in the liquid phase by addition of ethanol to isobutene catalyzed by sulfonic acid ion exchange resins. A generalized Langmuir-Hinshelwood rate expression is formulated in terms of the liquid phase activities of the reactants that is quasi-autocatalytic due to ethanol. This microkinetic model is combined with the generalized Maxwell-Stefan equations for a detailed investigation of the influence of multicomponent mass transfer limitations inside the macropores of the heterogeneous catalyst. The model is used for revision of experimental rate data for ETBE synthesis in the literature. The analysis reveals that reverse diffusion of isobutene can occur by strong interaction with ethanol and the catalyst effectiveness factor can exceed unity.