octane number reflects a lower tendency of the hydrocarbon to undergo a rapid,
inefficient detonation in an internal combustion engine. This rapid detonation can
be heard as an audible knocking or pinging sound in the engine, so octane is often
referred to as the antiknock quality of a gasoline. Motor fuel octanes are measured
at low engine speeds (research octane number, or RON, as measured by ASTM
Table 2 Reformate
composition
Component
Mass%
Liq-vol%
Aromatics
Benzene
3.72
3.39
Toluene
13.97
12.93
Ethylbenzene
3.13
2.90
p-Xylene
3.39
3.14
m-Xylene
7.47
6.91
o-Xylene
4.83
4.47
C9+ aromatics
36.05
33.30
Total aromatics
72.56
67.04
Paraffins and naphthenes
Propane
0.00
0.00
Isobutane
0.14
0.20
n-Butane
0.94
1.32
Isopentane
2.52
3.29
n-Pentane
1.74
2.29
Cyclopentane
0.10
0.10
C6 isoparaffins
3.91
4.77
n-Hexane
1.74
2.12
Methylcyclopentane
0.28
0.30
Cyclohexane
0.03
0.03
C7 isoparaffins
7.70
9.02
n-Heptane
2.22
2.60
C7 cyclopentanes
0.33
0.35
Methylcyclohexane
0.04
0.04
C8 isoparaffins
2.86
3.24
n-Octane
0.62
0.70
C8 cyclopentanes
0.14
0.14
C8 cyclohexanes
0.06
0.06
C9 naphthenes
0.04
0.04
C9 paraffins
0.90
0.99
C10 naphthenes
0.04
0.04
C10 paraffins
0.24
0.26
C11 naphthenes
0.00
0.00
C11 paraffins
0.03
0.04
Total paraffins
25.56
30.84
Total olefins
0.82
1.02
Total naphthenes
1.06
1.10
236
M.P. Lapinski et al.