Dehydration of isobutanol to isobutene in a slurry reactor
The April 1990 Alternative Fuels Proposal to the Department of Energy involved the development of new technology, based on the liquid phase process, for conversion of coal-derived synthesis gas to oxygenated hydrocarbon fuels, fuel additives, and fuel intermediates. The objective of this work was to develop a slurry reactor based process for the dehydration of isobutanol to isobutene. The isobutene can serve as a feedstock for the high octane oxygenated fuel additive methyl tertiary-butyl either (MTBE). Alumina catalysts were investigated because of their wide use as a dehydration catalyst. Four commercially available alumina catalysts (Catapal B, Versal B, Versal GH, and Al-3996R) were evaluated for both activity and selectivity to the branched olefin. All four catalysts demonstrated conversions greater than 80% at 290 C, while conversions of near 100% could be obtained at 330 C. The reaction favors low pressures and moderate to low space velocities. A yield of 0.90 mole isobutene per mole reacted isobutanol or better was obtained at conversions of 60--70% and higher. From 75 to 98% conversion, the four catalysts all provide isobutene yields ranging from 0.92 to 0.94 with the maximum occurring around 90% conversion. At low conversions, the concentration of diisobutyl ether becomes significant while the concentration of linear butenes is essentially a linear function of isobutanol conversion. Doping the catalyst with up to 0.8 wt % potassium showed a modest increase in isobutene selectivity; however, this increase was more than offset by a reduction in activity. Investigations using a mixed alcohols feed (consistent with isobutanol synthesis from syngas) demonstrated a small increase in the C4 iso-olefin selectivity over that observed for a pure isobutanol feed. 55 refs.
- Research Organization:
- Air Products and Chemicals, Inc., Allentown, PA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC22-91PC90018
- OSTI ID:
- 171265
- Report Number(s):
- DOE/PC/90018-T11; ON: DE96003944; TRN: AHC29602%%28
- Resource Relation:
- Other Information: PBD: Feb 1994
- Country of Publication:
- United States
- Language:
- English
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01 COAL, LIGNITE, AND PEAT
2-METHYLPROPANOL
DEHYDRATION
2-METHYLPROPENE
SYNTHESIS
ALUMINIUM OXIDES
CATALYTIC EFFECTS
CHEMICAL FEEDSTOCKS
FUEL ADDITIVES
ETHERS
CHEMICAL REACTION YIELD
THERMODYNAMICS
DOPED MATERIALS
CHEMICAL REACTION KINETICS
LIQUID PHASE METHANOL PROCESS
MODIFICATIONS
EXPERIMENTAL DATA