Cetane numbers (C#) for the homologous series of straight-chain, saturated n-alcohols, C5−C12 and C14, were determined according to ASTM D 613. Measured C# ranged from 18.2–80.8 and increased linearly with carbon number (CN). Regression analyses developed equations that related various physical properties or molecular characteristics of these alcohols to calculated C#. The degree of relationship between measured and calculated C# was expressed as R2. The decreasing order of the precision with which these properties correlated with C# was: boiling point (bp)>melting point (mp)>CN>heat of combustion (HG)>refractive index (n20D)>density (d). This ranking was based upon R2 (0.99–0.96) and the Average % error (2.8–7.2%). C# were also determined for straight-chain homologs of saturated methyl esters with CN of 6, 10, 12, 14, 16 and 18. C# ranged from 18.0–75.6 and increased curvilinearly with CN. Equations were also developed that related physical properties of these esters to C#. The precision with which these properties correlated with C# was: bp>viscosity (V)>heat of vaporization (HV)>HG>CN>surface tension (ST)>mp>n20D>d. R2 ranged from 0.99 for bp to 0.98 for d. Equations for the alcohols were linear or quadratic, while equations for the esters were linear, quadratic or cubic based upon statistical considerations that included a Student’s t-test. With related physical properties and these equations, accurate predictions of C# can be made for saturated n-alcohols and methyl esters.
[1]
M. D. Schrock,et al.
Methyl and ethyl soybean esters as renewable fuels for diesel engines
,
1984
.
[2]
Carroll E. Goering,et al.
Methyl soyate as a fuel in a diesel tractor
,
1985
.
[3]
E. H. Pryde,et al.
TRIGLYCERIDE/AQUEOUS ETHANOL/1-BUTANOL MICROEMULSIONS
,
1983
.
[4]
Kenton R Kaufman,et al.
Sunflower methyl esters for direct injected diesel engines.
,
1984
.
[5]
M. Kharasch.
Heats of combustion of organic compounds
,
1929
.
[6]
E. H. Pryde,et al.
TRIGLYCERIDE–METHANOL MICROEMULSIONS
,
1985
.
[7]
A. Schwab,et al.
Preparation and properties of diesel fuels from vegetable oils
,
1987
.
[8]
M. O. Bagby,et al.
Correlation of heats of combustion with empirical formulas for fatty alcohols
,
1989
.
[9]
M. O. Bagby,et al.
Heats of combustion of fatty esters and triglycerides
,
1989
.
[10]
W. E. Klopfenstein.
Effect of molecular weights of fatty acid esters on cetane numbers as diesel fuels
,
1985
.
[11]
John Aurie Dean,et al.
Lange's Handbook of Chemistry
,
1978
.