Page 329 - 9780077418427.pdf

/Users/user-f465/Desktop
tiL12214_ch12_299-322.indd Page 306 9/3/10 6:13 PM user-f465
tiL12214_ch12_299-322.indd Page 306 9/3/10 6:13 PM user-f465 /Users/user-f465/Desktop

H H H H H H H
Hydrocarbon name Petroleum products
H C C C C C C C H

Methane CH 4 H H H H H H H
Natural gas
Ethane C 2 H 6
A n-heptane, C 7 H 16
Propane C 3 H 8
LPG
Butane C 4 H 10
Pentane C 5 H 12 H
Petroleum
Hexane C 6 H 14
ether H C H
Heptane C 7 H 16
Octane C 8 H 18 Gasoline H H H H
Nonane
C 9 H 20
H C C C C C H
Decane C 10 H 22
Undecane C 11 H 24 H H H
Dodecane C 12 H 26
H C H H C H
Tridecane C 13 H 28
Tetradecane C 14 H 30 Kerosene H H
Pentadecane C 15 H 32 B trimethylpentane (or iso-octane), C 8 H 18
Hexadecane C 16 H 34
Diesel FIGURE 12.12 The octane rating scale is a description of
Heptadecane C 17 H 36 Lube fuel
Octadecane C 18 H 38 oils how rapidly gasoline burns. It is based on (A) n-heptane, with an
assigned octane number of 0, and (B) trimethylpentane, with an
Nonadecane C 19 H 40
Petrolatum assigned number of 100.
Eicosane C 20 H 42
FIGURE 12.11 Petroleum products and the ranges of is produced by the process. Without the reforming that pro-
hydrocarbons in each product. duces unleaded gasoline, low- numbered hydrocarbons (such as
ethylene) can be produced. Ethylene is used as a raw material for
many plastic materials, antifreeze, and other products. Cracking
TABLE 12.3 is also used to convert higher-numbered hydrocarbons, such as
heating oil, into gasoline.
Petroleum products
Kerosene is a mixture of hydrocarbons that have from 12
Carbon Atoms to 15 carbon atoms. The petroleum product called kerosene is
Name Boiling Range (°C) per Molecule also known by other names, depending on its use. Some of these
Natural gas Less than 0 C 1 to C 4 names are lamp oil (with coloring and odorants added), jet fuel
(with a flash flame retardant added), heating oil, #1 fuel oil, and
Petroleum ether 35–100 C 5 to C 7
in some parts of the country, “coal oil.”
Gasoline 35–215 C 5 to C 12
Diesel fuel is a mixture of a group of hydrocarbons that have
Kerosene 35–300 C 12 to C 15
from 15 to 18 carbon atoms per molecule. Diesel fuel also goes
Diesel fuel 300–400 C 15 to C 18
by other names, again depending on its use, for example, die-
Motor oil, grease 350–400 C 16 to C 18
sel fuel, distillate fuel oil, heating oil, or #2 fuel oil. During the
Paraffin Solid, melts at about 55 C 20
summer season, there is a greater demand for gasoline than for
Asphalt Boiler residue C 40 or more heating oil, so some of the supply is converted to gasoline by the
cracking process.
Motor oil and lubricating oils have 16 to 18 carbon atoms
per molecule. Lubricating grease is heavy oil that is thickened
which could be obtained with a mixture that is 87 percent with soap. Petroleum jelly, also called petrolatum (or Vaseline),
trimethylpentane and 13 percent n-heptane. Gasoline, however, is a mixture of hydrocarbons with 16 to 32 carbon atoms per
is a much more complex mixture. molecule. Mineral oil is a light lubricating oil that has been de-
It is expensive to process gasoline because some of the colorized and purified.
straight-chain hydrocarbon molecules must be converted into Depending on the source of the crude oil, varying amounts
branched molecules. The process is one of “cracking and reform- of paraffin wax (C 20 or greater) or asphalt (C 36 or more) may be
ing” some of the straight-chain molecules. First, the gasoline is present. Paraffin is used for candles, waxed paper, and home
passed through metal tubes heated to 500°C to 800°C (932°F to canning. Asphalt is mixed with gravel and used to surface roads.
1,470°F). At this high temperature, and in the absence of oxy- It is also mixed with refinery residues and lighter oils to make
gen, the hydrocarbon molecules decompose by breaking into a fuel called #6 fuel oil or residual fuel oil. Industries and utili-
smaller carbon-chain units. These smaller hydrocarbons are ties often use this semisolid material that must be heated before
then passed through tubes containing a catalyst, which causes it will pour. Number 6 fuel oil is used as a boiler fuel, costing
them to reform into branched-chain molecules. Unleaded gasoline about one-half as much as #2 fuel oil.

306 CHAPTER 12 Organic Chemistry 12-8