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Oral Presentation 7-05
Lignin
Conversion to C7 - C9 Methoxybenzenes as High-Octane
Gasoline
Components - an Ideal Replacement for MTBE
J. Shabtai,a W. Zmierczak,a
and E. Chornet b a Department of Chemical & Fuels Engineering University of Utah Salt Lake City, Utah 84112
b National Renewable Energy
Laboratory Golden, Colorado 80401 Telephone: (801) 581-5151; Fax: (801) 585-9291; E-mail: joseph.shabtai@m.cc.utah.edu A two-stage process for selective lignin conversion to methoxybenzenes has been developed. Stage I of the process involves a sequence of mild base-catalyzed depolymerization (BCD) and mild, non-deoxygenative hydrotreatment (HT) of the lignin to yield a fully depolymerized intermediate product, mainly consisting of monocyclic phenols. In Stage II, this intermediate phenolic product, is subjected to exhaustive etherification (ETR) with methanol to yield (selectivity, 75 - 88 wt%) a mixture of methoxybenzenes having 0 to 2, predominantly 1 or 2, ring substituents. The final C7 - C9 methoxybenzene products have critically important advantages as high-octane additives in comparison with other O-containing compounds, in particular dialkylethers, e.g., methyl-t-butyl ether (MTBE). The latter has been recently rejected as a gasoline additive, due to (a) its high volatility (b.p., 55 ºC) and the associated unacceptable level of air polluting effect, and (b) its high solubility in water and consequent undesirable pollution effect on underground water. In contrast, C7 - C9 methoxybenzenes are characterized by relatively lower volatility (b.p.’s in the range of 154 - 195 ºC, viz. in the upper gasoline range) and consequent lack of any significant effect on air pollution, as well as lack of solubility in water and anticipated lack of any pollution effect on underground water. A second major advantage of C7 - C9 methoxybenzenes is their extraordinarily high blending octane numbers in the approximate range of 142 - 166. These superior properties, coupled with the anticipated high efficiency of the low temperature BCD-ETR procedure, indicate that lignin-derived C7 - C9 methoxybenzenes could provide an ideal replacement of currently rejected dialkylethers, e.g., MTBE, as choice octane number enhancers for petroleum-derived hydrocarbon gasolines.
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