Health & Environmental Research Online (HERO)


tert-Amyl ethyl ether (TAEE)


210 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Murine cytochrome P4503A is induced by 2-methyl-3-buten-2-ol, 3-methyl-1-pentyn-3-ol(meparfynol), and tert-amyl alcohol

Authors: Mannering, GJ; Shoeman, JA (1996) Xenobiotica 26:487-493. HERO ID: 817390

[Less] 1. Colupulone, a constituent of hops, was shown to be a potent inducer of hepatic P4503A in mouse. The . . . [More] 1. Colupulone, a constituent of hops, was shown to be a potent inducer of hepatic P4503A in mouse. The olefin, 2-methyl-3-buten-2-ol (RC = CH2), is formed from lupulones when hops are exposed to atmospheric hydroxyl radicals. This suggested the possibility that the same reaction may occur in vivo. The credibility of this hypothesis was enhanced when RC = CH2 was shown to induce P4503A in mouse. Ethylmorphine (EM) N-demethylation, a functional marker for P4503A, was also induced by RC = CH2. 2. 3-Methyl-1-pentyn-3-ol (RC identical to meparfynol), a sedative and close structural analogue of RC = CH2, also induced P4503A and EM N-demeythylation. Tert-amyl alcohol (RC-CH3), the saturated analogue of RC = CH2, was included in t he study with the expectation that it would serve as a negative control for the anticipated induction of P4503A by the other two alcohols. This proved not to be the case; RC-CH3 was about as active an inducer of P4503A as RC = CH2 and RC identical to CH. The possibility is considered that, like valproic acid, RC-CH3 is metabolized to an olefin by P450. 3. Hydroxylation of aniline and benzo[a]pyrene by hepatic microsomes from mice treated with the three alcohols were used as functional markers for the induction of P4502E and P4501A respectively. RC = CH2 at the two lowest levels of administration suppressed aniline hydroxylation but had no effect at the highest level. RC identical to CH was ineffective and RC-CH3 was moderately inductive at all three levels. Each of the three compounds were weak to moderate inducers of benzo[a]pyrene hydroxylation.

Technical Report
Technical Report

Odor threshold studies performed with gasoline and gasoline combined with MTBE, ETBE and TAME, with cover letter dated 02/22/95

Author: TRC Environmental Consultants Inc. (1995) (86950000131; 86950000131). Washington, DC. Office of Toxic Substances.
: Office of Toxic Substances. HERO ID: 1248102

Abstract: No abstract available.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

ETHERS FROM ETHANOL .2. REACTION EQUILIBRIA OF SIMULTANEOUS TERT-AMYL ETHYL ETHER SYNTHESIS AND ISOAMYLENE ISOMERIZATION

Authors: Kitchaiya, P; Datta, R (1995) Industrial and Engineering Chemistry Research 34:1092-1101. HERO ID: 1195736

[Less] The recent requirements for blending oxygenates with gasoline for pollution abatement and octane improvement . . . [More] The recent requirements for blending oxygenates with gasoline for pollution abatement and octane improvement have opened up huge markets for ethers, synthesized by catalytically reacting an isoolefin with an alcohol. Consequently, alternatives to isobutylene-derived methyl tert-butyl ether (MTBE) obtained from methanol and ethyl tert-butyl ether (ETBE) obtained from ethanol are being explored. This paper provides a thermodynamic analysis of the liquid-phase etherification of ethanol with 2-methyl-1-butene (2M1B) and 2-methyl-2-butene (2M2B), the two reactive isoamylene isomers. Both these isomers produce tert-amyl ethyl ether (TAEE) but also undergo isomerization. Theoretical and experimental results are provided here for the simultaneous TAEE synthesis and isoamylene isomerization. Expressions for the three thermodynamic equilibrium constants as a function of temperature are developed. Gibbs free energy and the enthalpy of formation of TAEE are also obtained. The equilibrium constants' correlations are utilized to compute the effect of the feed mole ratio of the isoamylenes and the inert solvent to ethanol as well as the reaction temperature on the equilibrium conversions and selectivities. Conditions that maximize etherification conversion and selectivity are explored.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

GAS-PHASE DECOMPOSITION OF CONJUGATE ACID IONS OF SIMPLE TERT-BUTYL ALKYL ETHERS

Authors: Audier, HE; Berthomieu, D; Morton, TH (1995) Journal of Organic Chemistry 60:7198-7208. HERO ID: 1193660

[Less] Unimolecular decompositions of protonated methyl (MTBE), ethyl (ETBE), n-propyl, isopropyl, and isobutyl . . . [More] Unimolecular decompositions of protonated methyl (MTBE), ethyl (ETBE), n-propyl, isopropyl, and isobutyl tert-butyl ethers have been examined experimentally and the results compared with the outcome of ab initio calculations. Extensive hydrogen transposition between the hydrogen on oxygen and the nine hydrogens of the tert-butyl is revealed by mass-resolved ion kinetic energy spectroscopy (MIKES) experiments on deuterated ions from MTBE and ETBE. Mechanistic possibilities are probed with the help of FT-ICR, and isotope effects are interpreted by comparison with the MIKES of protonated ethyl tert-amyl ether and its deuterated analogues. Protonated MTBE displays a single unimolecular decomposition product, tert-butyl cation. Of the protonated MTBE ions that decompose, 30% do so without any hydrogen transposition, while 70% completely randomize the non-methoxy hydrogens. This calls for the intervention of at least two noncovalent intermediates. In the case of MTBE, Hartree-Fock-based SCF computations exhibit only one plausible candidate that corresponds to an energy minimum, the hydrogen-bonded complex between protonated methanol and isobutene. The other intermediate is inferred to be the ion-neutral complex [MeOH tBu(+)], even though that does not correspond to a well on the SCF potential energy surface. Protonated ETBE yields a pair of unimolecular decomposition products, tert-butyl cation and protonated acetaldehyde. Here the ab initio results display two noncovalent potential energy minima, but the observed ion intensities cannot be accounted for without at least three intermediates. Again, the conclusion is that the additional intermediate corresponds to an ion-neutral complex, [EtOH tBu(+)], which does not correspond to a potential energy minimum. The transient ion-neutral complexes have non-zero lifetimes because their collapse is prevented by entropic (rather than energetic) barriers.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Genotoxicity and twenty-eight-day subchronic toxicity studies on tertiary amyl methyl ether

Authors: Daughtrey, WC; Bird, MG (1995) Journal of Applied Toxicology 15:313-319. HERO ID: 77210

[Less] Tertiary amyl methyl ether (TAME) is an oxygenate with a potential role as a component in reformulated . . . [More] Tertiary amyl methyl ether (TAME) is an oxygenate with a potential role as a component in reformulated gasolines. The genotoxic potential of TAME was assessed In an Ames assay and a mouse micronucleus assay. The Ames assay was carried out using five standard salmonella strains and doses ranging from 100 to 10000 p.g per plate. Tertiary amyl methyl ether was not mutagenic in any of the strains, either with or without metabolic activation. In the micronucleus assay, mice were given a single intraperitoneal injection of TAME at doses of 0.15, 0.375 or 0.75 g kg'. Bone marrow samples were collected and evaluated for micronucleus formation at 24, 48 and 72 h after dosing. No elevation in micronucleus frequency was observed at any dose or at any of the collection times. Thus, TAME was not clastogenic to mouse bone marrow under the conditions of this study. Preliminary test data Indicated that the acute oral LD5 for TAME in Sprague-Dawley rats was ca. 2.1 g kg-1. In the 28-day subchronic study, Sprague-Dawley rats of both sexes were dosed orally with vehicle, 0.125, 0.5 or 1.0 g kg-1day-1 TAME in corn oil at a dose volume of 2 ml/kg-1. Dosing continued 7days a week for a period of 28 days. Deaths of two out of 10 animals In the high-dose group (1 g kg-1 day-1) appeared to be compound related. Food consumption and body weights were reduced in the high-dose male group relative to controls; otherwise, clinical observations were minimal. Dose-related Increases in adrenal and kidney weights were observed but no histopathological changes were evident in any of the tissues examined. It is concluded that while some evidence of toxicity was observed at the highest dose, TAME is oflow oral toxicity following repeated dosing. The no-observed-effect level (NOEL) for this study was 0.125 g kg-1day1 and the no-observed-adverse-effect level (NOAEL) was 0.5 g kg-1 day-1.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

VAPOR-PRESSURES OF METHYL TERT-BUTYL ETHER, ETHYL TERT-BUTYL ETHER, ISOPROPYL TERT-BUTYL ETHER, TERT-AMYL METHYL-ETHER, AND TERT-AMYL ETHYL ETHER

Authors: Krahenbuhl, MA; Gmehling, J (1994) Journal of Chemical and Engineering Data 39:759-762. HERO ID: 2324859

[Less] The vapor pressures of methyl tert-butyl ether, ethyl tert-butyl ether, isopropyl tert-butyl ether, . . . [More] The vapor pressures of methyl tert-butyl ether, ethyl tert-butyl ether, isopropyl tert-butyl ether, tert-amyl methyl ether, and tert-amyl ethyl ether were measured by ebulliometry or the static method in the pressure ranges 14-102 and 3-835 kPa (methyl tert-butyl ether), respectively. The data were correlated using the Antoine and Wagner equations. The experimental data of methyl tert-butyl ether and ethyl tert-butyl ether were compared with data available in the literature.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

REACTION EQUILIBRIA IN THE SYNTHESIS OF 2-METHOXY-2-METHYLBUTANE AND 2-ETHOXY-2-METHYLBUTANE IN THE LIQUID-PHASE

Authors: Rihko, LK; Linnekoski, JA; Krause, AOI (1994) Journal of Chemical and Engineering Data 39:700-704. HERO ID: 1199115

[Less] Equilibrium constants for the liquid-phase synthesis of 2-methoxy-2-methylbutane (TAME) and 2-ethoxy-2-methylbutane . . . [More] Equilibrium constants for the liquid-phase synthesis of 2-methoxy-2-methylbutane (TAME) and 2-ethoxy-2-methylbutane (TAEE) were measured in the temperature range 323-363 K. The equilibria were studied using the alcohol/alkene mixture in various mole ratios and the respective ether as a reagent in a batch reactor. A commercial cation exchange resin (Amberlyst 16) was used as the catalyst. The system was strongly nonideal, and the UNIQUAC estimation method was used in the calculation of the liquid-phase activity coefficients. The experimental equilibrium constants are given as a function of temperature. At 333 K the equilibrium constants K(a) for the synthesis of TAME were 39.6 +/- 2.5 from methanol and 2-methyl-1-butene (2M1B) and 4.1 +/- 0.3 from 2-methyl-2-butene (2M2B). The equilibrium constants for the synthesis of TAEE were 17.4 +/- 1.1 from ethanol and 2M1B and 1.7 +/- 0.1 from 2M2B. The experimental DELTA(r)H values for the liquid-phase synthesis of TAME were -33.6 +/- 5.1 kJ.mol-1 (2M1B) and -26.8 +/- 2.3 kJ.mol-1 (2M2B), and those for the synthesis of TAEE were -35.2 +/- 5.8 kJ.mol-1 (2M1B) and -27.3 +/- 6.7 kJ.mol-1 (2M2B). The results were compared with the literature values.

Technical Report
Technical Report

Methods for derivation of inhalation reference concentrations and application of inhalation dosimetry

Author: U.S. EPA (1994) (EPA/600/8-90/066F). Research Triangle Park, NC: U.S. Environmental Protection Agency, Office of Research and Development, Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office. [EPA Report] HERO ID: 6488

[Less] This document describes the U .S . Environmental Protection Agency (EPA) methodology for estimation . . . [More] This document describes the U .S . Environmental Protection Agency (EPA) methodology for estimation of inhalation reference concentrations (RfCs) (earlier terminology was inhalation reference dose or RfDi) as benchmark estimates of the quantitative doseresponse assessment of chronic noncancer toxicity for individual inhaled chemicals. Noncancer toxicity refers to adverse health effects other than cancer and gene mutations. This overview chapter discusses general principles of dose-response assessment for noncancer toxicity, the development of the RfC methodology, and its role within the context of the risk assessment process. Subsequent chapters of the document discuss criteria and information to be considered in selecting key studies for RfC derivation, provide an overview of the respiratory system and its intra- and interspecies variables, and discuss areas of uncertainty and data gaps in relation to the proposed methodology.

Technical Report
Technical Report

Chemical assessments and related activities (CARA)

Author: U.S. EPA (1994) (600/R-94/904; OHEA-I-127). Washington, DC: U.S. Environmental Protection Agency, Office of Health and Environmental Assessment. [EPA Report] HERO ID: 596444


Technical Report
Technical Report

Odor and taste threshold studies performed with tertiary-amyl methyl ether (TAME) with cover letter dated 02/22/95.

Author: API (1993) (Doc #86950000132; Publication No. 4591). Washington, D.C.: American Petroleum Institute. HERO ID: 75917

[Less] Oxygenated compounds such as methyl-tertiary-butyl-ether (MTBE) have been used as gasoline additives . . . [More] Oxygenated compounds such as methyl-tertiary-butyl-ether (MTBE) have been used as gasoline additives to enhance octane for a number of years. More recently, the Clean Air Act Amendments of 1990 require that gasoline containing specific amounts of oxygenates be sold in certain areas of the country that are in non-attainment for carbon monoxide or ozone. Because of the expected increase in demand for oxygenates, alternatives to MTBE, such as TAME (tertiary-amyl-methyl-ether), are expected to be produced in greater volumes. In response, API initiated a series of projects to gain basic information on TAME properties and characteristics including odor and taste, aquatic toxicity, and dermal sensitization.

This report presents the results of the study to evaluate TAME's odor detectability and recognition thresholds in air and water, as well as its taste threshold in water. The odor detection threshold is the lowest concentration at which an odor can be noticed; recognition threshold is the concentration at which an odor can be rated in intensity. Taste threshold is the concentration in water at which some taste can be discerned.

The odor thresholds were determined by a panel of six adult volunteers who "passed" a screening study with butyl alcohol as the odorant. The taste threshold was determined in an analogous manner, using distilled water as the diluent; however, the volunteers did not swallow the test solutions. The average odor detection and recognition threshold values for TAME were determined to be 0.027 and 0.047 ppm, respectively. The average odor detection and recognition threshold values for TAME in water were determined to be 0.194 and 0.443ppm respectively. In general, compounds with odor thresholds below 1 ppm are considered highly odorous. The panelists' descriptions of TAME's odor included sweet, rubbery, fruity, ether-like and paint-like.The average taste detection threshold value for this oxygenate was determined to be 0.128 ppm. The panelists found the taste of TAME to be highly objectionable.