Methyl terf-butyl ether

Hardison L, SS Curie, LM Ciuffeti, MR Hyman (1997) Metabolism of diethyl ether and cometabolism of methyl terf-butyl ether by a filamentous fungus, a Graphium sp. Appl Environ Microbiol 63 3059-3167. 

Hatzinger PB, K McClay, S Vainberg, M Tugusheva, CW Condee, RJ Steffan (2001) Biodegradation of methyl terf-butyl ether by a pure bacterial culture. Appl Environ Microbiol 67 5601-5607. 

A constituent in gasoline. Harley et al. (2000) analyzed the headspace vapors of three grades of unleaded gasoline where ethanol was added to replace methyl terf-butyl ether. The gasoline vapor concentrations of 2-methylpentane in the headspace were 9.3 wt % for regular grade, 9.8 wt % for... 

Degradation of methyl terf-butyl ether by bifunctional aluminum in the presence of oxygen was investigated by Lien and Wilkin (2002). Bifunctional aluminum was synthesized by sulfating aluminum metal with sulfuric acid. When the initial methyl terf-butyl ether concentration was 14.4 mg/L, 90% of methyl ferf-butyl ether degraded within 24 h forming acetone, methyl acetate, tert-hniyX alcohol, and ferf-butyl formate. Carbon disulfide was tentatively identified as a reaction product by GC/MS. Product yields were 27.6% for acetone, 18.4% for methyl acetate, 21% for tert-hniyX alcohol, and 6.1% ferf-butyl formate. When the initial concentration of methyl tert-butyl ether was reduced to 1.4 mg/L, 99.5% of methyl terCbutyl ether reacted. Yields of acetone, methyl acetate, and /erf-butyl alcohol were 54.7,17.2, and 13.2, respectively. 

The formal isomerization enthalpies of methyl n-butyl ether to methyl terf-butyl ether and of di-n-butyl ether to n-butyl ferf-butyl ether are about —24kJmoU (Iq) and —26.5 kJmol (g), respectively. From these, and the experimental enthalpy of formation of di-ferf-butyl peroxide, the enthalpies of formation of di-n-butyl peroxide are ca —333 kJmol (Iq) and —288 kJmol (g), wildly divergent from the reported values. 

Figure 7.6a gives the response surface of the partition coefficient of sulphacetamide. It can be seen that optimal extraction conditions of sulphacetamide are binary compositions of methylene chloride and methyl terf.-butyl ether. It can also be observed that the partition coefficient is nearly constant at the binary axis methylene chloride/chloroform. Therefore, small variations in the binary compositions of methylene chloride and chloroform will not significantly change the partition coefficient. In other words binary compositions with methylene and chloroform yield robust extractions for sulphacetamide. This conclusion is confirmed by the robustness plot of the partition coefficient of sulphacetamide (Figure 7.6b). This plot also shows that under conditions where the partition coefficient is optimal (binary mixtures of methylene chloride and methyl tert.-butyl ether), the robustness of the partition coefficient reaches a maximum value.

There are other commercial processes available for the production of butylenes, However, these are site- or manufacturer-specific, e.g.. the Oxi-rane process for the production of propylene oxide the disproportionation of higher olefins and the oligomerization of ethylene, Any of these processes can become an important source in the future. More recently, the Coastal Isobutane process began commercialization to produce isobutylene from butanes for meeting the expected demand for methyl-terf-butyl ether (MTBE). 

Methyl terf-Butyl Ether and Ethyl tert-Butyl... 

Mobile Phases (A) Hexane and (B) methyl-terf-butyl ether (use HPLC grade filtered through 0.2-p.m filter). 

Bierwagen, B.G., Keller, A.A. (2001) Measurement of Henry s law constant for methyl terf-butyl ether using solid-phase microextraction. Environ. Toxicol. Chem. 20, 1625-1629. 

Fig. 3.5. Schematic diagram of a sonochemical reaction system for the sonolytic destruction of methyl terf-butyl ether. (Reproduced with permission of the American Chemical Society.)...

Occurrence of Methyl terf-Butyl Ether in Water... 

Methyl terf-butyl ether (MTBE) is an important industrial product used as oxygenate additive in reformulated gasoline. Environmental concern makes its future uncertain, however. Although mainly manufactured by reaction of isobutylene with methanol, it is also produced commercially from methanol and fcrr-butyl alcohol, a by-product of propylene oxide manufacture. Numerous observations from the use of heteropoly acids have been reported. These compounds were used either as neat acids [74], or supported on oxides [75], silica or K-10 montmorillonite [76]. They were also used in silica-included form [77] and as acidic cesium salts [74,77]. Other catalysts studied were sulfated ZrOj [76], Amberlyst 15 ion-exchange resin [76], HZSM-5 [76], HF-treated montmorillonite, and commercial mineral acid-activated clays [75]. Hydrogen fluoride-treatment of montmorillonite has been shown to furnish particularly active and stable acid sites thereby ensuring high MTBE selectivity (up to 94% at 413 K) [75]. 

Hollow fiber membranes made from poly(imide)/sulfonated PES, with a phthalide group, exhibit a high selectivity in the vapor permeation of mixtures of methanol and methyl-terf-butyl ether (MTBE) as high as 12,000. The structures of the polymers used are shown in Figure 7.11. 

Catalysts that decrease reaction rates are usually referred to as inhibitors. They often act by interfering with the free-radical processes involved in chain reactions, and the mechanism usually differs from that involved in accelerating a reaction. The most familiar example of the use of inhibitors has historically been the addition of additives such as tetraethyllead or methyl terf-butyl ether to gasoline to improve its antiknock properties. 

The chromatogram shown in Fig. 3 was the first separation profile of oligomeric procyanidins by HSCCC using a two-phase solvent system. In recent times, other hydrophilic solvent systems, such as hexane/methyl acetate/acetonitrile/ water three-phase system,methyl terf-butyl ether/l-buta-noFacetonitrile/water two-phase systems,and ethyl acet-ate/1-butanol (or 2-propanol)/water two-phase systems, were also applied to HSCCC separations of other proantho-cyanidins and/or related polyphenolic oligomers. 

Hydroalkoxylation reactions refer to the addition of an alcohol over an insaturation. This highly atom economical process is potentially a straightforward and clean access to ethers, and the reaction is successfully applied at the industrial level for the production of MTBE (methyl terf-butyl ether) and ETBE (ethyl tert-butyl ether) from isobutylene and methanol or ethanol. If this transformation is well known with activated olefins (reaction referred to a Michael addition), a real challenge is the synthesis of ethers from unactivated olefins. Veiy few reactions involving carbohydrates or polyols have been reported to date and most of them involve isobutylene as this substituted olefin is prompt to generate stabilized carbenium ion under acidic conditions. Dimerization reactions of the alcohol or isobutylene are the main side reactions that have to be avoided in order to reach high selectivities into the desired ethers. ... 

Nakamura, S. and Daishima, S. Simultaneous determination of 22 volatile organic compounds, methyl-terf-butyl ether, 1,4-dioxane, 2-methylisoborneol, and geosmin in water by headspace solid-phase microextraction-eas chromatography-mass spectrometry. Analytica Chimica Acta 2005, 548 (1-2), 79-85. 

Methyl terf-butyl ether (MTBE) was once used as a gasoline octane booster, but was phased out after it appeared as a low-level water pollutant in the United States. Levels of this chemical in recreational lakes and reservoirs were attributed largely to emissions of unburned fuel from recreational motorboats and personal watercraft having two-cycle engines that discharge their exhausts directly to the water. 

Methyl terf-butyl ether [te/f Butyl methyl ether (MTBE)[ C3H 0 1634-04-4 50 ppm ... 

Much recent attention has been cast on one particular additive to gasoline, methyl tert-butyl ether (MTBE). Most polymer and detergent additives in addit-ized fugitive products have a high affinity for the polar soil surfaces and stay at the spill site. Methyl terf butyl ether is unusual because when present in a fugitive gasoline product (almost all RFC contains MTBE due to its low vapor pressure... 

HSiCls, EtsN, 2-chloro-l,3-dimethylimidazolinium chloride, dry tetrahydrofuran, dry methyl terf-butyl ether, dry diethyl ether. 

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