Tert-amyl Methyl Ether Research Articles

Neural network and support vector machine predictive control of tert-amyl methyl ether reactive distillation column

An algorithm of model predictive control based on artificial neural network and least-square support vector machine method is presented for a class of industrial process with strong nonlinearity such as tert-amyl methyl ether (TAME). Integral constant is added to improve the performance of the controller. In the present work, two different control methodologies neural network predictive control (NNPC) and support vector machine-based predictive control (SVMPC) are implemented and compared with a conventional proportional-integral-derivative (PID) control methodology to a TAME reactive distillation column. The simulation result shows that both NNPC and SVMPC gives better control performance than PID for set-point change as well as for load change of±10% in methanol feed flow rate and molar ratio of methanol to isoamylene in reactor effluent feed.

Health assessment of gasoline and fuel oxygenate vapors: Micronucleus and sister chromatid exchange evaluations

Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m3 of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard.

Health assessment of gasoline and fuel oxygenate vapors: Developmental toxicity in rats

Gasoline-vapor condensate (BGVC) or condensed vapors from gasoline blended with methyl t-butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME) diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA) were evaluated for developmental toxicity in Sprague–Dawley rats exposed via inhalation on gestation days (GD) 5–20 for 6h/day at levels of 0 (control filtered air), 2000, 10,000, and 20,000mg/m3. These exposure durations and levels substantially exceed typical consumer exposure during refueling (<1–7mg/m3, 5min). Dose responsive maternal effects were reduced maternal body weight and/or weight change, and/or reduced food consumption. No significant malformations were seen in any study. Developmental effects occurred at 20,000mg/m3 of G/TAME (reduced fetal body weight, increased incidence of stunted fetuses), G/TBA (reduced fetal body weight, increased skeletal variants) and G/DIPE (reduced fetal weight) resulting in developmental NOAEL of 10,000mg/m3 for these materials. Developmental NOAELs for other materials were 20,000mg/m3 as no developmental toxicity was induced in those studies. Developmental NOAELs were equal to or greater than the concurrent maternal NOAELs which ranged from 2000 to 20,000mg/m3. There were no clear cut differences in developmental toxicity between vapors of gasoline and gasoline blended with the ether or alcohol oxygenates.

Health assessment of gasoline and fuel oxygenate vapors: Reproductive toxicity assessment

Vapor condensates of baseline gasoline (BGVC), or gasoline-blended with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA) were evaluated for reproductive toxicity in rats at target concentrations of 2000, 10,000, or 20,000mg/m3, 6h/day, 7days/week. BGVC and G/MTBE were assessed over two generations, the others for one generation. BGVC and G/MTBE F1 offspring were evaluated for neuropathology and changes in regional brain glial fibrillary acidic protein content. No neurotoxicity was observed. Male kidney weight was increased consistent with light hydrocarbon nephropathy. In adult rats, decreased body weight gain and increased liver weight were seen. Spleen weight decreased in adults and pups exposed to G/TBA. No pathological changes to reproductive organs occurred in any study. Decreased food consumption was seen in G/TAME lactating females. Transient decreases in G/TAME offspring weights were observed during lactation. Except for a minor increase in time to mating in G/TBA which did not affect other reproductive parameters, there were no adverse reproductive findings. The NOAEL for reproductive and offspring parameters was 20,000mg/m3 for all vapor condensates except for lower offspring NOAELs of 10,000mg/m3 for G/TBA and 2000mg/m3 for G/TAME.

Health assessment of gasoline and fuel oxygenate vapors: Immunotoxicity evaluation

Female Sprague Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess potential immunotoxicity of evaporative emissions. Test articles included vapor condensates prepared from “baseline gasoline” (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/mg3 administered for 6h/day, 5days/week for 4weeks. The antibody-forming cell (AFC) response to the T-dependent antigen, sheep erythrocyte (sRBC), was used to determine the effects of the gasoline vapor condensates on the humoral components of the immune system. Exposure to BGVC, G/MTBE, G/TAME, and G/TBA did not result in significant changes in the IgM AFC response to sRBC, when evaluated as either specific activity (AFC/106 spleen cells) or as total spleen activity (AFC/spleen). Exposure to G/EtOH and G/DIPE resulted in a dose-dependent decrease in the AFC response, reaching the level of statistical significance only at the high 20,000mg/m3 level. Exposure to G/ETBE resulted in a statistically significant decrease in the AFC response at the middle (10,000mg/m3) and high (20,000mg/m3) exposure concentrations.

Sulfonated carbon materials with hydrophilic and lipophilic properties

Two acidic carbon materials (H-PRC and HS-C) were used as catalysts for the condensation reaction of methanol with formaldehyde to produce dimethoxymethane (DMM) in aqueous solution (hydrophilic system) and for the etherification of isopentene with methanol to produce tert amyl methyl ether (TAME) in toluene solution (lipophilic system). Microcalorimetric adsorptions of water and benzene showed that the HS-C was highly hydrophilic without the lipophilicity, while the H-PRC exhibited both the hydrophilicity and lipophilicity. Thus, the HS-C was well dispersed in aqueous solution and difficult to separate from it. On the other hand, the H-PRC was highly active, more active than the acidic resin (D008) and sulfuric acid, for the synthesis of DMM in aqueous solution. The H-PRC was also highly active, more active than the HS-C, for the etherification of isopentene with methanol to produce TAME in toluene solution, probably owing to its amphiphilic surface property as well as its strong surface acidity as measured by the microcalorimetric adsorption of NH3.

Determination of fuel ethers in water by membrane extraction ion mobility spectrometry

Fuel oxygenates are environmentally detrimental compounds due to their rapid migration to groundwater. Fuel oxygenates have been reported to cause taste and odour problems in drinking water, and they also have long-term health effects. Feasible analytical methods are required to observe the presence of fuel oxygenates in drinking and natural water. The authors studied ion mobility spectrometry (IMS) to determinate isomeric fuel ether oxygenates; ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME), separated from aqueous matrices with a pervaporation membrane module. Methyl tert-butyl ether (MTBE) was also membrane extracted and detected with IMS. The authors demonstrated that fuel ethers (MTBE, ETBE, DIPE, and TAME) can be quantified at μg/L level with membrane extraction IMS. A membrane extraction module coupled to IMS is a time and cost effective analysis method because sampling can be performed in a single procedure and from different natural water matrices within a few minutes. Consequently, IMS combined with membrane extraction is suitable not only for waterworks and other online applications but also in the field monitoring the quality of drinking and natural water.

Single Photon Ionization/Photoelectron Ionization-Membrane Introduction Mass Spectrometry for On-line Analysis Ethers Gasoline Additive in Water

A magnetic field enhanced photoelectron ionization (MEPEI) source combined with single photon ionization (SPI) for membrane inlet time-of-flight mass spectrometry was used for on-line detection of ether gasoline additive. Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl tert-amyl ether (TAME) and isopropyl ether (DIPE) were selected as the typical pollutants. A membrane inlet was used to transfer the analytes from liquid into gas phase in an on-line manner by pervaporization without sample pretreatment. Less sample fragments were in SPI, and molecular ions could be used to quick preliminarily qualitative analysis; high energy electrons and fragmentations produced by MEPEI can be used to accurate qualitative isomers and overcame the problem of resolution of overlapping peaks in complex matrix when using direct injection. Under the optimal conditions such as membrane temperature 60 degrees C, membrane thicknesses 50 mu m and membrane areas 160 cm(2), the single sample analysis time was less than 100 s, and the limits of detection for MTBE, ETBE, TAME and DIPE were 5.5, 4.8, 3.3 and 4.3 mu g/L, respectively. The instrument has been successfully applied to rapid analysis of MTBE in simulated water by gasoline.

Volumetric behavior of the ternary system benzene-2-methoxy-2-methylbutane-2,2,4-trimethylpentane and all binary sub-systems at temperature range (298.15–318.15) K

Densities of ternary liquid mixtures composed of benzene, 2-methoxy-2-methylbutane (i.e. tert-amyl methyl ether, TAME), and 2,2,4-trimethylpentane (i.e. isooctane, 2,2,4-TMP) are measured at three temperatures 298.15K, 308.15K, and 318.15K at atmospheric pressure by a vibrating-tube densimeter as well as all its binary sub-systems. Excess molar volumes of the mixtures are calculated from the experimental densities and then correlated using the Redlich–Kister equation. The determination of its adjustable parameters is made by the method of least squares. For all studied systems, the positive deviations from ideal behavior are observed at all temperatures. The excess molar volume curves of binary systems differ in the shape and temperature dependence. The experimental binary data are compared with literature data and discussed. The ternary system mentioned above is measured newly. Moreover, the experimental excess molar volumes are compared to the calculation using Peng–Robinson equation with a corrected parameter. The novelty of this work is the prediction of ternary excess molar volumes from binary parameters in Peng–Robinson equation.

Model predictive control and neural network predictive control of TAME reactive distillation column

Model predictive control (MPC) is an advantageous methodology to control the nonlinear processes such as tert-amyl methyl ether (TAME). Multiple reactions of the system make the synthesis of the TAME process more complicated which exhibits highly nonlinear behavior. The need to handle such difficult control problem has led to use neural network in MPC. In the present work, three different control strategies, viz., conventional PID control, model predictive control and neural network predictive control (NNPC) are implemented to a TAME reactive distillation column (RDC). All these controllers are compared and it is found that NNPC and MPC give smoother and better control performance than the PID controller for both set point change and ±10% load change in feed flow rate of methanol.

Craniofacial abnormalities and altered wnt and mmp mRNA expression in zebrafish embryos exposed to gasoline oxygenates ETBE and TAME

Gasoline additives ethyl tert butyl ether (ETBE) and tertiary amyl methyl ether (TAME) are used world wide, but the consequence of developmental exposure to these hydrophilic chemicals is unknown for aquatic vertebrates. The effect of ETBE and TAME on zebrafish embryos was determined following OECD 212 guidelines, and their toxicity was compared to structurally related methyl tert-butyl ether (MTBE), which is known to target developing vasculature. LC50s for ETBE and TAME were 14mM [95% CI=10–20] and 10mM [CI=8–12.5], respectively. Both chemicals caused dose dependent developmental lesions (0.625–10mM), which included pericardial edema, abnormal vascular development, whole body edema, and craniofacial abnormalities. The lesions were suggestive of a dysregulation of WNT ligands and matrix metalloproteinase (MMP) protein families based on their roles in development. Exposure to 5mM ETBE significantly (p≤0.05) decreased relative mRNA transcript levels of mmp-9 and wnt3a, while 2.5 and 5mM TAME significantly decreased wnt3a, and wnt8a. TAME also significantly decreased mmp-2 and -9 mRNA levels at 5mM. ETBE and TAME were less effective in altering the expression of vascular endothelial growth factor-a and -c, which were the only genes tested that were significantly decreased by MTBE. This is the first study to characterize the aquatic developmental toxicity following embryonic exposure to ETBE and TAME. Unlike MTBE, which specifically targets angiogenesis, ETBE and TAME disrupt multiple organ systems and significantly alter the mRNA transcript levels of genes required for general development.

Critical Evaluation of the 2D-CSIA Scheme for Distinguishing Fuel Oxygenate Degradation Reaction Mechanisms

Although the uniform initial hydroxylation of methyl tert-butyl ether (MTBE) and other oxygenates during aerobic biodegradation has already been proven by molecular tools, variations in carbon and hydrogen enrichment factors (ε(C) and ε(H)) have still been associated with different reaction mechanisms (McKelvie et al. Environ. Sci. Technol. 2009, 43, 2793-2799). Here, we present new laboratory-derived ε(C) and ε(H) data on the initial degradation mechanisms of MTBE, ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) by chemical oxidation (permanganate, Fenton reagents), acid hydrolysis, and aerobic bacteria cultures (species of Aquincola, Methylibium, Gordonia, Mycobacterium, Pseudomonas, and Rhodococcus). Plotting of Δδ(2)H/ Δδ(13)C data from chemical oxidation and hydrolysis of ethers resulted in slopes (Λ values) of 22 ± 4 and between 6 and 12, respectively. With A. tertiaricarbonis L108, R. zopfii IFP 2005, and Gordonia sp. IFP 2009, ε(C) was low (<|-1|‰) and ε(H) was insignificant. Fractionation obtained with P. putida GPo1 was similar to acid hydrolysis and M. austroafricanum JOB5 and R. ruber DSM 7511 displayed Λ values previously only ascribed to anaerobic attack. The fractionation patterns rather correlate with the employment of different P450, AlkB, and other monooxygenases, likely catalyzing ether hydroxylation via different transition states. Our data questions the value of 2D-CSIA for a simple distinguishing of oxygenate biotransformation mechanisms, therefore caution and complementary tools are needed for proper interpretation of groundwater plumes at field sites.

Steady-state simulation of a reactive internally heat integrated distillation column (R-HIDiC) for synthesis of tertiary-amyl methyl ether (TAME)

Tertiary-amyl methyl ether (TAME) is a very important fuel additive, which has attracted the attention of many researchers. In this article, the synthesis of TAME by a reactive internally heat integrated distillation column (R-HIDiC) is investigated. A complex mathematical formulation is developed for simulating the proposed reactive heat integrated distillation column (R-HIDiC), based on material balance, equilibrium, summation of mole fractions and enthalpy balance (MESH) equations. The suggested model is used for simulating an R-HIDiC for industrial production of TAME. The performance of the proposed R-HIDiC is compared to the conventional reactive distillation column which is usually used in TAME production plants. The model verification has been performed using industrial data of the conventional TAME reactive distillation. The simulation results show that the total energy consumption of the proposed R-HIDiC is about 22% less than that of the conventional reactive distillation column.

Liquid–liquid equilibria for ternary mixtures of methyl tert-amyl ether + methanol (or ethanol) + imidazolium-based ionic liquids at 298.15 K

Liquid–liquid equilibria (LLE) were determined for ternary systems {methyl tert-amyl ether (TAME)+methanol+1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4])}, {TAME+ethanol+[Bmim][BF4]}, {TAME+methanol+1-ethyl-3-methylimidazolium ethylsulfate (EMISE)} and {TAME+ethanol+EMISE} at 298.15K. Experiments were carried out at atmospheric pressure using stirred and thermo-regulated cells. The experimental data were correlated with the well-known non random two liquid (NRTL) and universal quasi chemical (UNIQUAC) activity coefficient models. In addition, the distribution coefficients and the selectivities of the ionic liquids of [Bmim][BF4] and EMISE for methanol and ethanol in the TAME phase were measured.

Biofilm formation and microbial activity in a biofilter system in the presence of MTBE, ETBE and TAME

Emerging water contaminants derived from unleaded gasoline such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME), are in need of effective bioremediation technologies for restoring water resources. In order to design the conditions of a future groundwater bioremediating biofilter, this work assesses the potential use of Acinetobacter calcoaceticus M10, Rhodococcus ruber E10 and Gordonia amicalis T3 for the removal of MTBE, ETBE and TAME in consortia or as individual strains. Biofilm formation on an inert polyethylene support material was assessed with scanning electron microscopy, and consortia were also analysed with fluorescent in situ hybridisation to examine the relation between the strains. A. calcoaceticus M10 was the best coloniser, followed by G. amicalis T3, however, biofilm formation of pair consortia favoured consortium M10–E10 both in formation and activity. However, degradation batch studies determined that neither consortium exhibited higher degradation than individual strain degradation. The physiological state of the three strains was also determined through flow cytometry using propidium iodide and 3′-dihexylocarbocyanine iodide thus gathering information on their viability and activity with the three oxygenates since previous microbial counts revealed slow growth. Strain E10 was observed to have the highest physiological activity in the presence of MTBE, and strain M10 activity with TAME was only maintained for 24 h, thus we believe that biotransformation of MTBE occurs within the active periods established by the cytometry analyses. Viable cell counts and oxygenate removal were determined in the presence of the metabolites tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA), resulting in TBA biotransformation by M10 and E10, and TAA by M10. Our results show that A. calcoaceticus M10 and the consortium M10–E10 could be adequate inocula in MTBE and TAME bioremediating technologies.

Control of TAME reactive distillation using Non-Dominated Sorting Genetic Algorithm-II

The control system performs poor in characteristics and even it becomes unstable, if improper values of the controller tuning constants are used. So it becomes necessary to tune the controller parameters to achieve good control performance with the proper choice of tuning constants. Many control problems involve simultaneous optimization of multiple variables that competing with each other. In this paper, the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) has been successfully applied to optimization of dynamic state of t-amyl-methyl-ether (TAME) reactive distillation process. This paper presents the tuning of Proportional–Integral–Derivative (PID) controllers by minimizing of two objective functions (overshoot and Integral of Absolute Error (IAE)) through the NSGA-II. Results show that genetic algorithm is more suitable method for optimal control of the TAME reactive distillation columns than traditional methods such as Tyreus–Luyben.

Vapor−Liquid Equilibrium in the Binary Systems 2-Butanol +tert-Amyl Methyl Ether, 2-Butanol + Heptane, and Heptane +tert-Amyl Methyl Ether

Consistent vapor−liquid equilibrium (VLE) data have been measured for the systems 2-butanol + tert-amyl methyl ether (TAME), 2-butanol + heptane, and heptane + tert-amyl methyl ether at (50, 75, and 94) kPa. Equilibrium determinations were performed in a VLE still with circulation of both phases. According to experimental results, binary mixtures composed by 2-butanol exhibit positive deviations from ideal behavior, and azeotropy is present over the whole range of experimental determinations. The n-heptane + tert-amyl methyl ether binary system, in turn, exhibits slight positive deviation from ideal behavior, and no azeotrope is present. The VLE data of the quoted binary mixtures were well-correlated using the Redlich−Kister, Wohl, nonrandom two-liquid (NRTL), Wilson, and universal quasichemical (UNIQUAC) equations.

Density, refractive index, excess molar volumes and deviations in molar refraction at 298.15 K for binary and ternary mixtures of DIPE (OR TAME) + 1‐methanol (or 1‐propanol) + trihexyltetra‐decylphosphonium bis (2,4,4‐trimethylpentyl) phosphinate

AbstractThe excess molar volumes (VE) and the deviations in molar refraction (ΔR) at 298.15 K were determined for the binary systems {diisopropyl ether (DIPE) + 1‐propanol}, {Tert‐amyl methyl ether (TAME) + methanol}, {DIPE + trihexyltetradecylphosphonium bis(2,4,4‐trimethylpentyl)phosphinate ([P666,14][TMPP])}, {TAME + [P666,14][TMPP]}, {methanol + [P666,14][TMPP]} and {1‐propanol + [P666,14][TMPP]} using a digital vibrating‐tube densimeter and a precision digital refractometer. The VE and ΔR were correlated with the Redlich–Kister equation for binary systems. In addition, the ternary VE and ΔR data at 298.15 K were predicted for the ternary systems {DIPE + 1‐propanol + [P666,14][TMPP]} and {TAME + methanol + [P666,14][TMPP]} by using the binary contribution model of Radojkovič with correlated sub‐binary Redlich–Kister parameters. © 2011 Canadian Society for Chemical Engineering

Removal of BTEX, MTBE and TAME from aqueous solutions by adsorption onto raw and thermally treated lignite

The removal of BTEX (benzene, toluene, ethyl-benzene and m-,p-,o-xylenes), MTBE (methyl tertiary butyl ether) and TAME (tertiary amyl methyl ether) from aqueous solutions by raw (Lraw) and thermally treated lignite at 250°C, 550°C and 750°C (L250, L550 and L750, respectively) was studied, through batch experiments. Selected physical characteristics of both raw and treated lignite such as surface area and pore volume distribution were determined. Competitive adsorption effects were also explored. It was proved that the examined lignite samples were quite effective in removing BTEX, MTBE and TAME from aqueous solutions, with sample treated at 750°C being the most effective. Among the contaminants, BTEX appeared to have the strongest affinity, based on mass uptake by lignite samples. BTEX presence was found to significantly prevent MTBE and TAME adsorption on lignite (up to ∼55%). In all cases, equilibrium was achieved within 3h. The kinetics data proved a closer fit to the pseudo second order model, while the isotherm experimental data were a better fit to the Freundlich model, producing in some cases values of the isotherm constant 1/n less than one, indicating favorable adsorption. Respective batch experiments using commercial activated carbon (AC) were also conducted for comparison.

Emissions from Ethers and Organic Carbonate Fuel Additives: A Review

This paper is a review of the available literature on the main features of 11 of the most widely adopted oxygenated additives to base gasoline and diesel, focusing particularly on the emissions from the oxygenates considered as additives. The oxygenated additives studied are methyl tert-butyl ether, ethyl tertiary butyl ether, tert-amyl ethyl ether, tertiary amyl methyl ether, isopropyl ether, dimethyl carbonate, dimethoxymethane, dibutyl ether, diglycol methyl ether, diethyl carbonate, and 2-methoxyethyl acetate.