Ethers, f-butyl

Quach, D. T. Giszkowski, N. A. Einlayson-Pitts, B. J. A New GG-MS Experiment for the Undergraduate Instrumental Analysis Laboratory in Environmental Ghemistry Methyl-f-butyl Ether and Benzene in Gasoline, /. Chem. Educ. 1998,... 

In addition to MTBE, two other ethers commonly used as fuel additives ate /n/f-amyl methyl ether (TAME) and ethyl in/f-butyl ether [637-92-3] (ELBE). There ate a number of properties that ate important in gasoline blending (see Gasoline and OPHER MOTOR fuels) (Table 3). 

Extraction of water with methylene chloride, removal of water from extract, volume reduction to 5 mL after solvent exchange to methyl-f-butyl ether... 

Salanitro JP, LA Diaz, MP Williams, HL Wisniewski (1994) Isolation of a bacterial culture that degrades methyl f-butyl ether. Appl Environ Microbiol 60 2593-2596. 

The reaction in Entry 8 was conducted in excess refluxing vinyl f-butyl ether, using 1.1 equivalent of Hg(OAc)2 to catalyze the exchange reaction. In Entry 9 a thermal reaction leads to formation of an eight-membered ring. 

Principles and Characteristics Although early published methods using SPE for sample preparation avoided use of GC because of the reported lack of cleanliness of the extraction device, SPE-GC is now a mature technique. Off-line SPE-GC is well documented [62,63] but less attractive, mainly in terms of analyte detectability (only an aliquot of the extract is injected into the chromatograph), precision, miniaturisation and automation, and solvent consumption. The interface of SPE with GC consists of a transfer capillary introduced into a retention gap via an on-column injector. Automated SPE may be interfaced to GC-MS using a PTV injector for large-volume injection [64]. LVI actually is the basic and critical step in any SPE-to-GC transfer of analytes. Suitable solvents for LVI-GC include pentane, hexane, methyl- and ethylacetate, and diethyl or methyl-f-butyl ether. Large-volume PTV permits injection of some 100 iL of sample extract, a 100-fold increase compared to conventional GC injection. Consequently, detection limits can be improved by a factor of 100, without... 

Etherol A process for making oxygenated fuels (e.g., methyl f-butyl ether) from C4-C6 hydrocarbons by reacting them with methanol over an acid resin catalyst in a fixed bed reactor under mild conditions. Developed by BP with Erdoel Chemie and first used in a refinery at Vohburg, Germany, in 1986. Four units were operating and one was under construction in 1988. 

Dimethyl sulfate, reaction with di-methylformamide, 47, 52 Dimethyl sulfoxide, in synthesis of phenyl f-butyl ether, 45, 89 potassium salt, preparation, 48, 109, 110... 

Conversion of MEM ethers to esters. 2-Methoxyethoxymethyl (MEM) ethers are converted into carboxylic esters by reaction with an anhydride in the presence of FeCl3 (0.4 equiv.) (equation I). Selective cleavage is possible in the presence of a benzyl ether but not in the presence of a f-butyl ether. Aromatic rings, if present, can undergo acylation. 

Generally, dissolved aromatics may be found quite far from the origin of a spill, but entrained hydrocarbons may be found in water close to the petroleum source. Oxygenates such as methyl-f-butyl ether (MTBE) are even more water soluble than aromatics and are highly mobile in the environment. 

One method (EPA 8020) that is suitable for volatile aromatic compounds is often referred to as benzene-toluene-ethylbenzene-xylene analysis, although the method includes other volatile aromatics. The method is similar to most volatile organic gas chromatographic methods. Sample preparation and introduction is typically by purge-and-trap analysis (EPA 5030). Some oxygenates, such as methyl-f-butyl ether (MTBE), are also detected by a photoionization detector, as well as olefins, branched alkanes, and cycloalkanes. 

Thermodynamic consistency of data on solutions can be tested by plotting In (71/72) against Xi and seeing whether the area between Zi = 0 and 0.5 is equal and opposite in sign to the area between 0.5 and 1.0. Such a plot is indicated in Figure 16.5 for solutions of methyl f-butyl ether and chloroform at 313.5 K (5). 

TABLE 17.3. Vapor Pressure and Composition for Solutions of Methyl f-Butyl Ether and Acetonitrile at 313.15 K. 

Initiating a remarkable series of papers in 2008-2009, Grubbs and Whited reported the formation of an Ir(I) carbene complex, 44, from the reaction of methyl f-butyl ether (MTBE) with Ozerov s (PNP)lrH2 (PNP = [N(2-P Pr2-4-Me-C6H3)2] ) and NBE [121-127]. C-H addition to (PNP)lr presumably occurs followed by... 

Wallington, T.J., Dagaut, P., Liu, R., and Kurylo, MJ. Gas-phase reactions of hydroxy radicals with the fuel additives methyl f-butyl ether and f-butyl alcohol over the temperature range 240-440 K, Environ. Sci. TechnoL, 22(7) 842-844, 1988c. Wallington, T.J. and Japar, S.M. Atmospheric chemistry of diethyl ether and ethyl ferf-butyl ether. Environ. Sci TechnoL, 25(3) 410-415, 1991. 

There has been an enormous technological interest in tertfa/j-butanol (tBA) dehydration during the past thirty years, first as a primary route to methyl te/f-butyl ether (MTBE) (1) and more recently for the production of isooctane and polyisobutylene (2). A number of commercializable processes have been developed for isobutylene manufacture (eq 1) in both the USA and Japan (3,4). These processes typically involve either vapor-phase tBA dehydration over a silica-alumina catalyst at 260-370°C, or liquid-phase processing utilizing either homogenous (sulfonic acid), or solid acid catalysis (e.g. acidic cationic resins). More recently, tBA dehydration has been examined using silica-supported heteropoly acids (5), montmorillonite clays (6), titanosilicates (7), as well as the use of compressed liquid water (8). 

Problem 14.6 Give the alkene and alcohol needed to prepare the following ethers by alkoxymercuration-demercuration (a) diisopropyl ether, (b) 1-methyl-l-methoxycyclopentane, (c) 1-phenyl-1-ethoxypropane, (d) di-f-butyl ether. ... 

Ethyl f-butyl ether Sfg1 Minor product... 

Peroxides. These are formed by aerial oxidation or by autoxidation of a wide range of organic compounds, including ethyl ether, allyl ethyl ether, allyl phenyl ether, benzyl ether, benzyl butyl ether, n-butyl ether, /50-butyl ether, f-butyl ether, dioxane, tetrahydrofuran, olefines, and aromatic and saturated aliphatic hydrocarbons. They accumulate during distillation and can detonate violently on evaporation or distillation when their concentration becomes high. If peroxides are likely to be present materials should be tested for peroxides before distillation (for tests see entry under "Ethers", in Chapter 2). Also, distillation should be discontinued when at least one quarter of the residue is left in the distilling flask. 

Various studies on the fate of the gasoline additive methyl-f-butyl ether (MTBE) have shown that it can be oxidized to t-butyl-formate (TBF) which happens particularly in the atmosphere ... 

Lithiation of 3-methoxyselenophene occurs in the 2-position (76BSF265). Selenienyl f-butyl ethers are convenient precursors of the corresponding hydroxy compounds they are available from the corresponding lithio derivative (Scheme 10) (76ACS(B)10l). 

Methyl f-Butyl Ether. MTBE is produced by reaction of isobutene and methanol on acid ion-exchange resins. The supply of isobutene, obtained from hydrocarbon cracking units or by dehydration of tert-butyl alcohol, is limited relative to that of methanol. The cost to produce MTBE from by-product isobutene has been estimated to be between 0.13 to 0.16/L ( 0.50—0.60/gal) (90). Direct production of isobutene by dehydrogenation of isobutane or isomerization of mixed butenes are expensive processes that have seen less commercial use in the United States. 

Tennakoon et al. (465) have studied, by conventional 13C NMR, the catalyzed conversion of 2-methylpropene (isobutene) to t-butanol (R = H) or to methyl-f-butyl ether i.e., 2-methyl-2-methoxy-propane (R = CH3) by... 

Benzyl, PMB30 and f-butyl ethers are not affected,31 while the very acid sensitive trityl and / -McOPh(Ph)2C-cthcrs are hydrolyzed, and the resulting... 

All protecting groups resist the action of PCC, including the following very acid-sensitive ones TMS ether,242 THP ether,243 f-butyl ether,244... 

The rate constants for the reactions between OH and a range of ethers and hydroxy ethers have been reported at 298 K233 as well as those for reactions between dimethyl ether and methyl f-butyl ether over the range 295-750 K.234 Data from the former study show deviations from simple structure-activity relationships which were postulated to arise due to H-bonding in the reaction transition states.233 The atmospheric lifetime of methyl ethyl ether has been determined to be approximately 2 days.235 Theoretical studies on the H-abstraction from propan-2-ol (a model for deoxyribose) by OH have been reported using ab initio methods (MP2/6-31G ).236 The temperature dependence (233-272 K) of the rate coefficients for the reaction of OH with methyl, ethyl, n-propyl, n-butyl, and f-butyl formate has been measured and structure-activity... 

A full paper on the conversion of alcohols into f-butyl ethers by treatment with t-butyl dicarbonate (B0C2O) and Mg(C10g)2 [or, less effectively, A1(C104)3] in CH2CI2 has elaborated upon the proposal made in a 2005 communication (see ORM 2005, p. 58). The process is now seen to involve initial formation of a mixed anhydride (18), which, catalysed by the metal, progresses to the product via a synchronous mechanism in a six-membered ring transition state (Scheme 6).42... 

MTBE methyl f-butyl ether THF tetrahydrofuran EA ethyl acetate C6H12. cyclohexane DIPE diisopropyl ether DMF dimethylformamide. 

Ni(cod)2, coordinated by DPPF, is superior to the Pd catalyst in some cases. Ni-catalysed preparation of the aryl f-butyl ethers 419 and the silyl ethers 421, and their facile deprotection offer a good synthetic method for phenols 420 and 422 from aryl bromides [208],... 

The product (benzyl f-butyl ether) is primary on the benzyl side and tertiary on the t-butyl side. So, an SN2 type displacement by potassium f-butoxide of benzyl bromide is one approach, and an acid-catalyzed (SN1) process of benzyl alcohol with isobutylene (2-methylpropene) is another method ... 

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