Hydrolysis of<i>tert</i>-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

O’Reilly, Kirk T.; Moir, Michael E.; Taylor, Christine D.; Smith, Christy A.; Hyman, Michael R.

doi:10.1021/es001431k

Cited by 48 publications

(37 citation statements)

References 42 publications

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“…As the monooxygenase involved in the degradation of acetone was clearly different (Table 4), acetone should not compete with MTBE and TBA. The degradation of TBF formed after oxidation of MTBE was previously shown to be a spontaneous hydrolysis at acidic pH (O'Reilly et al, 2001). No data were available on the fate of TBF at neutral pH.…”

Section: Limiting Factors At the First Oxidationmentioning

confidence: 99%

Limitations in Mtbe Biodegradation

Fayolle

François

Garnier

et al. 2003

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Étapes limitantes dans la biodégradation du MTBE -La voie métabolique de dégra-dation du méthyl tertio butyl éther ou MTBE chez Mycobacterium austroafricanum IFP 2012 a été partiellement élucidée par identification des intermédiaires de dégradation. Elle nécessite l'induction de différentes activités enzymatiques. Au cours des premières étapes de la dégradation du MTBE en tertio butyl alcool (TBA), une même monooxygénase est responsable de l'oxydation du MTBE et du TBA avec une faible affinité pour le TBA (Km = 1,1 mM) et une estérase est impliquée dans l'hydrolyse du tertio butyl formiate (TBF). La lenteur de la dégradation du MTBE chez M. austroafricanum IFP 2012 semble due à un processus complexe combinant principalement un effet négatif du TBF formé au cours de l'oxydation du MTBE sur la MTBE/TBA monooxygénase et l'absence de la dégradation du TBA par la monooxygénase en présence de MTBE. Dans les étapes ultérieures de la dégradation, un besoin spécifique en cations Co ++ intervient au cours de la dégradation de l'acide 2-hydroxyisobutyrique (HIBA), la croissance sur HIBA étant très faible en absence de cette supplémentation. Abstract -Limitations in MTBE Biodegradation

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Section: Limiting Factors At the First Oxidationmentioning

confidence: 99%

Limitations in Mtbe Biodegradation

Fayolle

François

Garnier

et al. 2003

Oil & Gas Science and Technology - Rev. IFP

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“…Although initial studies suggested that MTBE was not subject to extensive biodegradation under anaerobic conditions (35,53), it is now known to be degraded, albeit slowly, under methanogenic (51), sulfate-reducing (43), iron-reducing (13), and nitrate-reducing (5) conditions. Little is presently known about the pathway of MTBE biodegradation under any of these conditions, although it has been suggested that the anaerobic biodegradation could be initiated by a hydrolytic mechanism (39). Like many other gasoline components, the rate of MTBE degradation is higher under aerobic than anaerobic conditions.…”

mentioning

confidence: 99%

Characterization of the Initial Reactions during the Cometabolic Oxidation of Methyl tert -Butyl Ether by Propane-Grown Mycobacterium vaccae JOB5

Smith

O’Reilly

Hyman

2003

Appl Environ Microbiol

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108

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The initial reactions in the cometabolic oxidation of the gasoline oxygenate, methyl tert-butyl ether (MTBE), by Mycobacterium vaccae JOB5 have been characterized. Two products, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), rapidly accumulated extracellularly when propane-grown cells were incubated with MTBE. Lower rates of TBF and TBA production from MTBE were also observed with cells grown on 1-or 2-propanol, while neither product was generated from MTBE by cells grown on casein-yeast extract-dextrose broth. Kinetic studies with propane-grown cells demonstrated that TBF is the dominant (>80%) initial product of MTBE oxidation and that TBA accumulates from further biotic and abiotic hydrolysis of TBF. Our results suggest that the biotic hydrolysis of TBF is catalyzed by a heat-stable esterase with activity toward several other tert-butyl esters. Propane-grown cells also oxidized TBA, but no further oxidation products were detected. Like the oxidation of MTBE, TBA oxidation was fully inhibited by acetylene, an inactivator of short-chain alkane monooxygenase in M. vaccae JOB5. Oxidation of both MTBE and TBA was also inhibited by propane (K i ‫؍‬ 3.3 to 4.4 M). Values for K s of 1.36 and 1.18 mM and for V max of 24.4 and 10.4 nmol min ؊1 mg of protein ؊1 were derived for MTBE and TBA, respectively. We conclude that the initial steps in the pathway of MTBE oxidation by M. vaccae JOB5 involve two reactions catalyzed by the same monooxygenase (MTBE and TBA oxidation) that are temporally separated by an esterase-catalyzed hydrolysis of TBF to TBA. These results that suggest the initial reactions in MTBE oxidation by M. vaccae JOB5 are the same as those that we have previously characterized in gaseous alkane-utilizing fungi.Methyl tert-butyl ether (MTBE) is presently an important component of many gasoline formulations used in the United States and several other countries. Low concentrations of MTBE (Ͻ3% vol/vol) were first added to gasoline in the United States in the 1980s to enhance the octane rating of unleaded gasoline. More recently, MTBE has been added as one of several oxygenating compounds intended to reduce automobile emissions of carbon monoxide and smog-related air pollutants. For this purpose MTBE is added to gasoline at concentrations in excess of 10% (vol/vol). The widespread use of MTBE and its recent detection in many urban groundwater supplies (44) have prompted concerns over the human health effects of chronic exposure to this compound through contaminated water supplies (26). The U.S. Environmental Protection Agency presently classifies MTBE as a possible human carcinogen and has issued a drinking water advisory for MTBE of 20 to 40 g/liter (parts per billion) (48).Ether bonds (49) and branched hydrocarbon skeletons (3) are features found in many compounds that are persistent in the environment. Although initial studies suggested that MTBE was not subject to extensive biodegradation under anaerobic conditions (35,53), it is now known to be degraded, albeit slowly, under methanogenic (51), s...

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“…27 But several authors 31,32 reported the possibility of TBA production by acid hydrolysis of MTBE during heated headspace analysis of acidified samples giving pH of between 1 and 2, and pH of sample is changed to 3 in this study. The stability of each target compound along time was studied by calculating the percentage of recoveries of spiked soil samples after 1, 2, 3 and 4 weeks.…”

Section: Resultsmentioning

confidence: 70%

Determination of MTBE, TBA and BTEX in Soil by Headspace Gas Chromatography-Mass Spectrometry

Shin¹

2012

Bulletin of the Korean Chemical Society

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A headspace gas chromatographic mass spectrometric (GC-MS) assay method was developed for the simultaneous determination of methyl tertiary butyl ether (MTBE), tert-butyl alcohol (TBA) and benzene, toluene, ethyl benzene and xylene (BTEX) in soil contaminated with gasoline. 2 g of soil sample were placed in a 10 mL headspace vial filled with 5 mL of phosphoric acid solution (pH 3) saturated with NaCl, and the solution was spiked with fluorobenzene as an internal standard and sealed with a cap. The vial was heated in a heating block for 40 min at 80 o C. The detection limits of the assay were 0.08-0.12 µg/kg for the analytes. For five independent determinations at 10 and 50 µg/kg, the relative standard deviations were less than 10%. The method was used to analyze fifty six soil samples collected from various regions contaminated with gasoline in Korea. The developed method may be valuable for the monitoring of the analytes in soil.

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Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

Cited by 48 publications

References 42 publications

Limitations in Mtbe Biodegradation

Limitations in Mtbe Biodegradation

Characterization of the Initial Reactions during the Cometabolic Oxidation of Methyl tert -Butyl Ether by Propane-Grown Mycobacterium vaccae JOB5

Determination of MTBE, TBA and BTEX in Soil by Headspace Gas Chromatography-Mass Spectrometry

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