Biorefinerías

In general, greater than 95% of the MTBE produced is used in the gasoline pool. MTBE is also used in the petrochemical industry for the production of isobutene. Additionally, it can be used in a number of chemical reactions including methacrolein, methycrylic acid, or isoprene production. One other use is solvent dewaxing of hydrocarbon oils (Peters et al. 2003). MTBE is produced by reacting isobutene with methanol in the presence of an acidic catalyst according to the following slightly exothermic reaction: i-C4H8 + CH3OH Æ (CH3)3COCH3 ∆Hr = -37 kJ/mol The reaction temperature and pressure are 30-100°C and 7-14 atm (100-200 psig), respectively (Schädlich et al. 2003), so that the reaction occurs in the liquid phase. Catalysts used are solid acids, zeolites (H-ZSM-5), and macroporous sulfonic acid ionexchange resins such as Amberlyst-15 (Collignon et al. 1999). A molar excess of methanol is used to increase isobutene conversion and inhibit the dimerization and oligomerization of isobutene. At optimum reaction conditions, MTBE yields approaching 90% can be achieved. In general, most commercially available processes are similar, consisting of a reaction and a refining section. In addition to the Snamprogetti and Hüls (now Oxeno) processes, processes have been developed by Arco, IFP, CDTECH (ABB Lummus Crest and Chemical Research Licensing), DEA (formerly Deutsche Texaco), Shell (Netherlands), Phillips Petroleum, and Sumitomo (Peters et al. 2003). Currently, there are over 140 MTBE plants with a total installed capacity of about 20 million tonnes/yr. The largest demand for MTBE has [primarily] been in the U.S., with North America consuming roughly 65% of the worldwide production of MTBE. U.S. consumption increased

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