Some heavier alcohols than ethanol have been considered as gasoline components, particularly bio-based isobutanol and n-butanol. In the past, “gasoline-grade” tert-butanol (GTBA) was commonly present in gasoline as a co-solvent for methanol and denaturant for ethanol. Properties of butanol are closer to gasoline than properties of ethanol; e.g. heating value, blending vapor pressure, water tolerance, corrosivity and polarity. Octane numbers of isobutanol and n-butanol are lower than those of ethanol. Blending ratio of butanol is higher than that of ethanol within the same oxygen limit, e.g. 3.6 wt-% oxygen is equivalent to 15-16 vol-% of butanol, but 10 vol-% of ethanol. Compatibility of isobutanol and n-butanol with conventional cars and infrastructure is better than that of ethanol. Butanol is not very aggressive towards materials and phase separation risk is low. There are limited emission studies concerning butanol as fuel, especially as concerns cars equipped with three-way catalyst. These tests have shown an increase in in volumetric fuel consumption when n-butanol was added into gasoline. CO, HC and NO_x emissions did not change significantly when n-butanol blend was compared to gasoline. Lower PM emission has been reported for butanol than for non-oxygenated gasoline with the direct injection car. Formaldehyde, acrolein, butyraldehyde, methacrolein, and some other unregulated emissions seem to increase with butanol containing fuels when compared to non-oxygenated gasoline.

Properties

• Production
• Chemical structure
• Legislation, standards and typical properties
• Melting point
• Octane numbers
• Volatility and distillation
• Heat of vaporization
• Flame temperatures
• Energy content
• Water tolerance
• Viscosity

Compatibility and emissions

• How much butanol can be used in conventional cars?
• Material compatibility, water tolerance
• Safety
• Drivability
• Combustion, power output and fuel consumption
• Exhaust emissions

References:

Aakko-Saksa, P., Rantanen-Kolehmainen, L., Koponen, P., Engman, A. and Kihlman, J. (2011) Biogasoline options – Possibilities for achieving high bio-share and compatibility with conventional cars. SAE International Journal of Fuels and Lubricants, 4:298–317 (also SAE Technical Paper 2011-24-0111). Full technical report: VTT report W187.

Andersen, V.F., Anderson, J.E., Wallington, T.J., Mueller, T.J. and O.J. Nielsen (2010) Vapor Pressures of Alcohol – Gasoline Blends. Energy Fuels 2010, 24, 3647-3654.

API (2001) Alcohols and Ethers – A Technical Assessment of Their Application as Fuels and Fuel Components. API Publication 4261. 3rd Edition, June 2001.

BASF Technical leaflets of isobutanol and n-butanol, edition 2008.

Baustian, J. (2012) Cold-Start/Warm-Up Vehicle Performance and Driveability Index for Gasoline Containing Isobutanol. Society of Automotive Engineers. Technical Paper SAE 2012-01-1741.

Beeckmann, J., Röhl, O. and Peters, N. (2009) Numerical and Experimental Investigation of Laminar Burning Velocities of Iso-Octane, Ethanol and n-Butanol. Society of Automo-tive Engineers. Warrendale. Technical Paper 2009-01-2784.

Black, G., Curran, H., Pichon, S., Simmie, J. and Zhukov, V. Bio-butanol: Combustion propser-ties and detailed chemical kinetic model. Combustion and Flame 157 (2010) 363-373.

BP (2006) 1-Butanol as a Gasoline Blending Bio-component. Presentation, 22 August 2006. Also as Wolf, L. (2007) “1-Butanol as a Gasoline Blending Bio-component”, presented at Mobile Sources Technical Review Subcommittee, USA, March 28, 2007.

Bruno, T.J., Wolk, A. and Naydich, A. (2009) Composition-Explicit Distillation Curves for Mixtures of Gasoline with Four-Carbon Alcohols (Butanols). Energy & Fuels 2009, 23, 2295-2306.

Butalco (2010) http://www.butalco.com

Butamax Advanced Biofuels (2010) http://www.butamax.com

ButylFuel (2010) http://www.butanol.com

Cairns, A. et al. (2009) A Study of Gasoline-Alcohol Blended Fuels in an Advanced Turbo-charged DISI Engine. Society of Automotive Engineers. Warrendale. Technical Paper 2009-01-0138.

Cooney, C., Wallner, T., McConnel, S., Gillen, J. Abell, C. and Miers, S. (2009) Effects of Blending Gasoline with Ethanol and Butanol on Engine Efficiency and Emissions Using a Direct-injection, Spark-ignition Engine. ASME. Technical Paper ICES2009-76155.

Exelus (2010) http://exelusinc.com

Gevo (2011) Isobutanol - A renewable solution for the transportation fuels value chain. Gevo White Paper, May 2011.

Gevo (2010) http://www.gevo.com

Gevo (2009) Gevo Inc. Press release, 30 September 2009 (newenergyandfuel.com).

Graboski, M. (2003) An analysis of Alternatives for Unleaded Petrol Additives in South Africa. Report.

Niass, T., Amer, A., Xu, W., Vogel, S., Krebber-Hortmann, K., Adomeit, P. and Brassat, A. Butanol Blending - a Promising Approach to Enchance the Thermodynamic Potential of Gasoline - Part 1. Society of Automotive Engineers. Technical Paper SAE 2011-01-1990.

Owen, K. and Coley, T. (1995) Automotive Fuels Reference Book. Society of Automotive Engineers. Warrendale. ISBN 1-56091-589-7.

Piel, W. and Thomas, R. (1990) Oxygenates for reformulated gasoline. Hydrocarbon process-ing, July 1990. p. 68-73.

Prezelj, M. (1987) Pool octanes via oxygenates. Hydrocarbon Processing. Vol. 66(9), 68-70.

Rice, R. et al. (1991) Fuel specifications and fuel property issues and their potential impact on the use of ethanol as a transportation fuel. Oak Ridge National Laboratory Ethanol Project. Subcontract No. 4500010570.

Rosenblatt, D., Morgan, C., McConnell, S., and Nuottimäki, J. Particulate Measurements: Ethanol and Isobutanol in Direct Injection Spark Ignited Engines. IEA-AMF Task 35-2, Final report.

Serras-Pereira, J., Aleiferis, P., Richardson, D. and Wallace, S. (2008) Characteristics of Ethanol, Butanol, Iso-Octane and Gasoline Sprays and Combustion from a Multi-Hole In-jector in a DISI Engine. Society of Automotive Engineers, Warrendale. Technical Paper 2008-01-1591.

Shapovalov, O. and Ashkinazi, L. (2008) Biobutanol: Biofuel of second generation. Russ. J. Org. Chem. 81(2008)2232-2236.

Stradling et al. (2009) Volatility and vehicle driveability performance of ethanol/gasoline blends: a literature review. CONCAWE report no. 8/09.

Thewes, M., Müther, M., Brassat, A., Pischinger, S. and Sehr, A. (2011) Analysis of the Effect of Bio-Fuels on the Combustion in a Downsized DI SI Engine. Society of Automotive Engineers. Technical Paper SAE 2011-01-1991.

Unzelman, G. (1991) U.S. Clean Air Act expands role for oxygenates. Oil & Gas Journal, April 15, 1991.

Wallner, T., Miers, A. and McConnell. (2009) A Comparison of Ethanol and Butanol as Oxygen-ates Using a Direct-Injection, Spark-Ignition Engine. Journal of Engineering for Gas Turbines and Power. ASME. Vol 131 / 032802.

Wallner, T. and Frazee, R. (2010) Study of regulated and non-regulated emissions from com-bustion of gasoline, alcohol fuels and their blends in a DI-SI engine. Society of Auto-motive Engineers. Technical Paper SAE 2010-01-1571.

Wallner, T., Ickes, A. and Lawyer, K. (2012) Analytical assessment of C2-C8 alcohols as spark-ignition engine fuels. FISITA Paper F2012-B01-004. Proceedings of the FISITA 2012 World Automotive Congress.

Wikipedia (2011) http://en.wikipedia.org/wiki/Ecalene

Yang., J. et al. (2009) Dyno Test Investigations of Gasoline Engine Fueled with Butanol-Gasoline Blends. Society of Automotive Engineers. Warrendale. Technical Paper 2009-01-1891.
Zwaja, S. and Naber, J. (2009) Combustion of n-butanol in a spark-ignition IC engine. Fuel (2010) 89, issue: 7, 1573-1582.