ETBE

MTBE-ETBE (methyl- or ethyl-tertiary butyl ether)... 

Typical feedstock composition and product properties for the synthesis of MTBE-ETBE. 

Liquefied gas fractions (propane, propylene, butanes, butenes) that will be able to provide feedstocks to units of MTBE, ETBE, alkylation, dimerization, polymerization after sweetening and/or selective hydrogenation. 

Ethers, such as MTBE and methyl / fZ-amyl ether (TAME) are made by a catalytic process from methanol (qv) and the corresponding isomeric olefin. These ethers have excellent octane values and compete on an economic basis with alkylation for inclusion in gasoline. Another ether, ethyl tert-huty ether (ETBE) is made from ethanol (qv) and isobutylene (see Butylenes). The cost and economic driving forces to use ETBE vs MTBE or TAME ate a function of the raw material costs and any tax incentives that may be provided because of the ethanol that is used to produce it. 

Some isopentane is dehydrogenated to isoamylene and converted, by processes analogous to those which produce methyl /-butyl ether [1634-04-4] (MTBE) to /-amyl methyl ether [994-05-8] (TAME), which is used as a fuel octane enhancer like MTBE. The amount of TAME which the market can absorb depends mostly on its price relative to MTBE, ethyl /-butyl ether [637-92-3] (ETBE), and ethanol, the other important oxygenated fuel additives. 

Biofuels. Biofuels are Hquid fuels, primarily used ia transportation (qv), produced from biomass feedstocks. Identified Hquid fuels and blending components iaclude ethanol (qv), methanol (qv), and the ethers ethyl /-butyl ether (ETBE) and methyl /-butyl ether (MTBE), as well as synthetic gasoline, diesel, and jet fuels. 

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

Ethyl Tertiary-Butyl Ether. Similar to methanol in the MTBE reaction, ethanol can react with isobutylene to produce ETBE. Which alcohol is used to make the ether is highly dependent on the relative cost of the alcohols. To make ethanol more economically competitive with methanol, the federal tax credit for biomass-based ethanol used in fuel also appHes to ethanol used to make ETBE in the United States (24). 

In addition to MTBE and MMT, other kinds of additives are being developed. Some of these are derivatives of alcohol. Variations of MTBE are also being used, especially the ether-derived ETBE (ethyl-t-butyl ether). 

Ethyl-ter-butyl ether (ETBE) is also produced by the reaction of ethanol and isobutylene under similar conditions with a heterogeneous acidic ion-exchange resin catalyst (similar to that with MTBE) ... 

Oxygen was added as oxygenated hydrocarbon components methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE), ethanol, methanol, and tertiary butyl alcohol (TBA). The properties of oxygenates, as they relate to gasoline blending, are shown in Table 10-1. 

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