The simultaneous production of tert-amyl alcohol and tert-amyl-ethyl ether in a reactive distillation column

Varışlı, Dilek
Due to the water pollution problems created by MTBE, significant research was focused on the production of alternative oxygenates, such as tert-amyl- ethyl-ether (TAEE), tert-amyl-methyl-ether (TAME) and higher alcohols as octane enhancing gasoline blending components. Tert-amyl alcohol (TAA) may also be considered as an attractive alternate to MTBE. These oxygenates are expected to improve the burning characteristics of gasoline and reduce exhaust emissions of CO and hydrocarbons. They may be produced by the reaction of C5 reactive olefins (isoamylenes), which are already present in FCC light gasoline, with ethanol, methanol or water. Reactive distillation processes have attracted significant attention in recent years, for the production of similar ethers (such as MTBE and TAME) to enhance the conversion in such equilibrium limited reactions.In the present study, simultaneous production of TAEE and TAA was investigated in a reactive distillation column using isoamylenes and ethanol- water mixture as reactants. Use of low purity ethanol (containing some water) in the production of such oxygenates might also offer a major advantage in terms of reactant cost. The batch reactive distillation column used in this work had 8 perforated plates and two of those plates were selected as the reaction zone. Amberlyst-15 catalyst packages (10g/plate) were placed over these two plates. Water/ethanol mole ratio in the liquid feed was 0.134, while mole fraction of isoamylene was changed between 0.03 and 0.18. Experiments were repeated in a temperature range between 70°-110°C. In this system, C5 reactive olefins were converted to TAEE and TAA by two competing parallel reactions, by reacting with ethanol and water, respectively. Very high conversions of C5 reactive olefins (over 93%) were achieved especially at high temperatures and low olefin concentrations. Selectivity of TAA with respect to TAEE was significantly increased of high temperature. It was shown that, water molecules were more strongly adsorbed on the -S03H sites of Amberlyst-15 than alcohols (forming a hydrogen bonded network) leading to poisoning of the catalyst for TAEE production.
Citation Formats
D. Varışlı, “The simultaneous production of tert-amyl alcohol and tert-amyl-ethyl ether in a reactive distillation column ,” M.S. - Master of Science, Middle East Technical University, 2003.