METHYL-tert-BUTYLETHER

CsH,20 Methyl tert-butylether (MTBE) CaHaNjOa 2,4-DinitiiQaniline... 

FIGURE 1.36 General scheme for the process of CPC and mobile phase flow regime for the descending mode of CPC (insert bottom left) used for the CPC separation of dichlorprop with [mono-ll-octadecylthio-h ls-10,ll-dihydroquinidinyl)]-l,4-phthalazine as chiral selector. Elution profiles for dichlorprop after injection of 366 mg racemate, amolar ratio r = 1 of loaded dichlorprop to total selector present in the rotor, and arotor speed of 1100 rpm. Stationary phase, 10 mM selector in methyl tert-butylether mobile phase, 100 mM sodium phosphate buffer (pH 8) flow rate 3 mLmin temperature, 25°C. (Reproduced from E. Gavioh et ah. Anal. Chem., 76 5837 (2004). With permission.)... 

Fig. 8.3 Lipase-catalyzed formation of 2-methoxy-/V-[(7/ )-l-phenylethyl]-acetamide (III) and fSj-phenylethylamine (IV). The reaction uses racemic 1-phenylethylamine (I) and ethylmethoxyacetate (II) as educts and is carried out in methyl-tert-butylether. As a byproduct, ethanol is formed.

The current libraiy of polyurethanes has some utility, and we will illustrate their uses with examples from our laboratory and from others. Currently, hydrophobic polyurethanes can be used to extract nonpolar pollutants, for example, from some pesticides. At the other end of the spectrum, hydrophilic polyurethanes can be used to extract sparingly soluble organic pollutants from groundwater. We will illustrate this with the extraction of methyl-tert-butylether. 

Methyl tert-ButylEther. Methyl /-butyl ether (MTBE) is an increasingly important fuel additive. Platinum—tin and other PGM catalysts are used for the dehydrogenation of isobutane to isobutene, an intermediate step in MTBE manufacture. 

MTBE (Methyl.-tert-butylether) is produced by reacting isobutene and methanol (MeOH) in the liquid phase ... 

Alavi, S., Ripmeester, J.A., and Klug, D.D. (2006) Molecular-dynamics simulations of binary structure H hydrogen and methyl-tert-butylether dathrate hydrates. /. Chem. Phys., 124, 204707. 

Methyl-tert-butylether and monoctanoin are solvents that are used for the rapid dissolution of cholesterol gallstones in patients who are not considered suitable for surgery. They are given by direct infusion into the gallbladder (1). However, they are suitable only for cholesterol stones, take too long to act, are often not successful, and have high rates of adverse effects (2). 

The results of contact dissolution of gallstones using infusions of methyl-tert-butylether by percutaneous trans-hepatic gallbladder puncture have been assessed in 803 patients (3). Stones were dissolved in 724 of 761 patients in whom gallbladder puncture was successful. The 30-day mortality was 0.4%. Common comphcations were biliary leak, fever, leukocytosis, abdominal pain, and mild increases in transaminases. Toxic effects due to ether were not reported. 

Fever, abdominal pain, nausea, vomiting, and diarrhea all occur frequently with methyl-tert-butylether and monoctanoin. Activities of serum amylase or liver enzymes can be slightly raised. 

Of 42 patients, 19 of whom received methyl tert-butyl-ether alone and 23 with bile acid-ethylenediaminetetra-acetate, there were mild complications in 40 vomiting in 12, pain at the start of treatment in 32, raised liver enzymes in six, and fever and leukocytosis in five (5). In those given methyl tert-butylether alone, there were two serious complications (gallbladder wall necrosis with... 

Cholecystitis can be induced, at least when methyl-tert-butylether is used alongside ethylenediaminetetra-acetic acid (SEDA-16, 428). Most such effects are probably attributable to over-rapid infusion. 

Test methods have been developed to measure ethers and alcohols in gasoline-range hydrocarbons, because oxygenated components such as methyl-tert-butylether and ethanol are common blending components in gasoline (ASTM D-4814, ASTM D-4815, ASTM D-5441, ASTM D-5599, ASTM D-5986 ASTM D-5622, ASTM D-5845, ASTM D-6293). 

Caution this transformation produces nitrogen gas. The reaction system should be vented. Do not run in a closed system This reaction may also be run with diethyl ether ) A suspension of the hydrazone (20.0 g, 43.2 mmol) in methyl tert-butylether (MTBE 400 mL) was treated with a solution of MeLi as a complex with LiBr (1.5 M in Et20, 86.3 mL, 0.13 mol) at room temperature for 1 h, cooled to 0 °C, and quenched with water (500 mL). The reaction was extracted with MTBE (1 L), the organic layer was dried (MgS04), and the solvent was removed in vacuo to give 12.0 g (99%) of the alkene as a white solid. 

Methyl-ferf-butyl-ether (MTBE synonymous with ferf-butyl methyl ether and methyl tert butylether) has been used as an additive for car fuels in Europe and the USA since the 1970s. Since the beginning of the 1980s MTBE has gained in importance as an additive in petrol in Germany. In 2001 the added MTBE quantity in gasolines in Germany totalled 680 0001 [1]. 

Williams-Hill D, Spears CP, Prakash S, Olah GA, Shamma T, Moin T, Kim LK, Hill CK (1999) Mutagenicity studies of methyl-tert-butylether using the Ames tester strain TA102. MutatRes 446 15-21... 

Liquid-liquid extraction of short-chain organic acids, ketoacids, or dicarboxylic acids result in low and often unreproducible extraction yields due to the hydrophilic character of the analytes. However, some authors report reproducible results for short-chain acids at mg/1 concentrations after liquid-liquid extraction at pH 2, although extraction yields remain low. Note also that organic solvents, namely diethylether, may be contaminated with organic acids. An unusual variation in liquid-liquid extraction is the use of tri-n-octylphosphine oxide (TOPO) in methyl-tert-butylether (MtBE) to enhance extraction yields, e.g., of acrylic acid in marine waters and of organic acids in aqueous solutions obtained from air collection chambers." TOPO s very low solubility in water and its high polarity make it suitable for extraction of polar compounds. The extraction yield for acrylic acid was 40% and its detection limit after derivatization with pentafluorobenzyl bromide was estimated to be 3 nM. ... 

Information for acertain parameter not available, if not given, na, not available DI, deionized water Cl, chemical ionization BCD, electron capture detector El, electron impact ionization FID, flame ionization detector MS, mass spectrometer MtBE, methyl tert-butylether MTBSTE, n-(tert-butyldimethylsilyl)-Wmethylfluoracetamide PDAM, 1-pyrenyldiazomethane PFBBr, pentafluorobenzyl bromide PEBOH, pentafluorobenzyl alcohol SPME, solid-phase microextraction TOPO, tri-n-octylphoshine oxide UASB, upflow anaerobic sludge blanket reactor. 

A. Refmger, Reaktionstechnische Un-tersuchungen zur FKlssigphasesyn-these von Methyl-tert-butylether (MTBE) an einem starksauren makro-porosen lonenaustauschharz als Kata-lysator, PhD Thesis, TU Clausthal, 1988. 

Table 7.5 Dependence of relative column capacity on the polarity of the mobile phase (LiChrosphere column, 250 mm x 4.6 nun, with methyl-tert-butylether (MTBE) modifier...

Figure 6 Positive ion atmospheric pressure chemical ionization (APCI) LC-MS analyses of (A) hexane extract of 200 fiL of human serum, and (B) solvent blank showing no signals at m/z 269. The computer-reconstructed mass chromatogram at m/z 269 is shown from the full-scale data. The HPLC solvent system consisted of a 25 min linear gradient from 50 44.5 5 0.5 to 50 4.5 45 0.5 methanol/water/methyl-tert-butylether/acetic acid (v/ v/v/v). (From Ref. 310.)...

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