See Methyl tert-butyl ether

Methyl tert-butylhydroquinone, 20 105 Methyl-tertiary-butyl ether. See Methyl-tert-butyl ether (MTBE) Methyltestosterone, registered for use in aquaculture in Australia, 3 222t Nb-Methyl tetrahydrofolic acid, 25 802 2-Methyltetrahydrofuran (METHF),... 

Typical normal-phase operations involved combinations of alcohols and hexane or heptane. In many cases, the addition of small amounts (< 0.1 %) of acid and/or base is necessary to improve peak efficiency and selectivity. Usually, the concentration of polar solvents such as alcohol determines the retention and selectivity (Fig. 2-18). Since flow rate has no impact on selectivity (see Fig. 2-11), the most productive flow rate was determined to be 2 mL miiT. Ethanol normally gives the best efficiency and resolution with reasonable back-pressures. It has been reported that halogenated solvents have also been used successfully on these stationary phases as well as acetonitrile, dioxane and methyl tert-butyl ether, or combinations of the these. The optimization parameters under three different mobile phase modes on glycopeptide CSPs are summarized in Table 2-7. 

Olefins, unlike paraffins, do not show significant gains in octane number with skeletal isomerization (see Table 14.2). As a result, olefin isomerization is not a useful octane boosting strategy. However, tertiary olefins (olefins with three alkyl substituents on the double bond), do react fairly readily with olefins to form ethers, which do have good octane numbers-for example, methyl tert-butyl ether (MTBE). 

In practice, short-chain alkanes and alkenes are normally used as feedstock for shape-selective catalytic formation of isooctanes at relatively low temperatures. Until the 1980s, lead alkyls (Section 18.1) were added to most automotive fuels to help suppress engine knock, but they have been phased out in North America because of the chronic toxicity of lead and lead compounds. The most commonly used nonlead antiknock additive is now methyl tert-butyl ether [MTBE CH30C(CH3)3], which is made by the reaction of methanol with 2-methylpropene, (CHs C—CH2 (see Section 7.4). The latter is obtained by catalytic cracking of petroleum fractions to give 1-butene, which is then shape-selectively isomerized on zeolitic catalysts. 

Ethyl tert-Butyl Ether. Ethanol can react with isobutylene to form ETBE much the same way as methanol is now processed into MTBE, methyl tert-butyl ether (see Ethers). 

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 />-dioxane are particularly prone to form explosive peroxides on prolonged storage and exposure to air andlight (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 tert-5 ky ethers such as methyl tert-butyl ether [1634-04-4] (MTBE) and ter1-axn.y methyl ether [994-05-8] (TAME). Both have shown little tendency if any to form peroxides (2,8). 

METHYLBUTYI- ETHANOATE see IHO850 METHYL BUTYL ETHER see BRU780 METHYL n-BUTYL ETHER see BRU780 METHYL tert-BUTYL ETHER see MHV859 METHYL tert-BUTYL ETHER (DOT) see MHV859 3-METHYLBUTYL FORMATE see IHSOOO 3-METHYLBUTYL 2-HYDROXYBENZOATE see IMEOOO... 

A somewhat different type of distillation with reaction is catalytic distillation fPoherty et al.. 2008 Parkinson. 200S1. In this process bales of catalyst are stacked in the column. The bales serve both as the catalyst and as the column packing (see Chapter 101. This process was used commercially for production of methyl tert-butyl ether (MTBE) from the liquid-phase reaction of isobutylene and methanol. The heat generated by the exothermic reaction is used to supply much of the heat required for the distillation. Since MTBE use as a gasoline additive has been oudawed because of pollution problems from leaky storage tanks, these units are shut down. Other applications of catalytic distillation include desulfurization of gasoline, separation of 2-butene from a mixed C4 stream, esterification of fatty acids and etherification. 

Other important aliphatic ethers include ethylene and propylene glycol ether that form from the respective epoxide hy water addition (see Section 6.12 for details) and methyl tert-butyl ether (MTBE) that is obtained from condensation of methanol and isobutanol or by addition of methanol to isobutene. 

Methyl-1,3-butadiene) see Isoprene (3-Methyl-1-butanol) see Isopentyl alcohol (4-Methyl-tert-butylbenzene) see p-tert-Butyltoluene (Methyl tert-butyl ether) see tert-Butyl methyl ether (3-Methylbutyl nitrite) see Isopentyl nitrite (3-Methylbutyraldehyde) see Isovaleraldehyde (Methyl CarbitoF ) see Methyldiglycol (Methyl Cellosolve ) see Methyl glycol... 

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