Fert-Butyl methyl ether MTBE

Ruthenium complex R,R)-S7 catalyzes a highly diastereo- and enantio-selective cycloaddition between methacrolein and a configurationally stable E-ketonitrone 86 (14JOC3414). The highest ewdo-selectivity was obtained when fert-butyl methyl ether (MTBE) was used as solvent. A reversed exocontrol was achieved by using different N- and O-substituents on nitrone 86 and toluene or CH2CI2 as solvent. 

Chemists almost invariably use common names for low-molecular-weight ethers. For example, although ethoxyethane is the lUPAC name for CH3CH2OCH2CH3, it is rarely called that rather, it is called diethyl ether, ethyl ether, or even more commonly, simply ether. The abbreviation for fert-butyl methyl ether is MTBE, after the common name methyl fert-butyl ether (incorrectly alphabetized, as you will recognize). 

The nature of the initiation step, which may occur in a variety of ways, is not known in all cases. Commonly used ethers such as ethyl ether, isopropyl ether, tetrahydrofuran, and i)-dioxane are particulady prone to form explosive peroxides on prolonged storage and exposure to air and light (see Peroxides AND PEROXY COMPOUNDS, ORGANIC), and should contain antioxidants (qv) to prevent their build-up. One of the exceptions to the peroxide forming tendency of ethers is methyl fert-alkyl ethers such as methyl fert-butyl ether [1634-04-4] (MTBE) and fert-amyl methyl ether [994-05-8] (TAME). Both have shown htde tendency if any to form peroxides (2,8). 

After the above discussion on RD of ideal ternary mixtures, in this section two nonideal ternary systems are considered. These are the heterogeneously catalyzed syntheses of the fuel ethers MTBE (methyl tert-butyl ether) and TAME (fert-amyl methyl ether) by etherification of methanol with isobutene or isoamlyenes respectively. Both reaction systems have enormous industrial importance because of the outstanding antiknock properties of MTBE and TAME as gasoline components. 

Figure 6.11.29 World demand for methanol by end use in 2007 [data from Saade (2009)] TAME = tert-amyl methyl ether, MTBE = methyl fert-butyl ether.

Methyl fert-Butyl Ether MTBE Methyl Tertiary Butyl Ether Noncyclic Aliphatic or Aromatic Ethers Tetrahydrofuran Organophosphonates... 

Construct a mechanism that shows why methyl tert-butyl ether (MTBE), a common gasoline additive, oxidizes in air to give formaldehyde as well as acetone, fert-butyl formate (HC(0)OC(CH 3),), and methyl acetate (CH3C(0)0CH3). 

Methyl fert-butyl ether (MTBE) synthesis 69,70 SMBCR... 

Mitsubishi Rayon in Japan has commercialized a three-step process on the basis of a two-step catalytic oxidation of isobutene, preferentially through f-butanol as primary intermediate. This process suffers not only from a relatively moderate overall MMA yield ( 80%), but also from increasing isobutene cost due to its alternative use for MTBE (methyl fert.-butyl ether) production as a gasoline additive. 

In the commercial synthesis of methyl fert-butyl ether (MTBE), once used as an antiknock, octane-improving gasoline additive, 2-methylpropene and methanol are passed over an acid catalyst to give the ether. Propose a mechanism for this reaction. (See Examples 5.5,5.6)... 

MTBE Methyl fert-butyl ether DIB Di-iso-butene or iso-octene WHSV Weight hourly space velocity PAI Polyamideimide... 

DCM, dichloromethane THF, tetrahydrofliran MTBE, methyl fert-butyl ether. 

DuPont claimed the use of a bis(diphenylphosphino)ferrocene-based tin-free Pt catalyst for isomerization-hydroformylation of the same substrate and obtained at 35% conversion >86% of methyl 5-formylpentanoate with a linearity of 93% [131]. Instead of the methyl ester, the free acid could also be used successfully as substrate. In the case of less regioselective hydroformylation, 5-formylvaleric acid could be advantageously separated from the other isomers by crystallization in methyl fert-butyl ether (MTBE) [132]. 

Schmidt, T.C. Analysis of methyl tert-hutyl ether (MTBE) and fert-butyl alcohol (TBA) in ground and surface water. TrAC—Trends in Analytical Chemistry 2003, 22 (10), 776-784. 

Fig. 4. Elution strengths of binary mixtures. If a vertical line is drawn through the nomogram, all of the corresponding mixtures will have the same strength. MTBE = methyl fert-butyl ether.

Felthouse and Mills (321) report the amination of methyl ferf-butyl ether (MTBE) and isobutene to fert-butylamine using alumino- and borosilicate pentasil molecular sieve catalysts. The ether and alkene amination reactions were found to proceed preferentially under SCF conditions at temperatures on the order of 330°C and pressures greater than 193 bar. The smdy showed that MTBE can be used as a substitute raw material for terf-butylamine manufacture, but MTBE decomposition products of isobutene, methanol, and methanol conversion products are produced that require a more complicated product separation process than with isobutene as the only C4 substrate. 

For the CB-DM, reversed phase is the mobile phase of choice, employing methanol predominantly as the organic modifier in water. The choice of modifier is dictated by the strength of the inclusion complex. It has been noted that methyl fert-butyl ether (MTBE) greatly improves peak efficiency, reduces retention, and enhances resolution on this phase (Fig. 7). The role of the MTBE is to further restrict the cavity access as it associates with the surface methoxy groups through a weak dipole interaction. It is important to note that in this case only methanol can be used as a modifier as acetonitrile will disassociate the MTBE from the CSP. 

Lee J K, Song I K and Lee W Y (1995), An experimental study on the application of polymer membranes to the catalytic decomposition of MTBE (methyl fert-butyl ether) , Catal Today, 25,345-349. 

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