Oil and gas production handbook An introduction to oil and gas production

Aromatic petrochemicals include benzene, toluene, and xylenes. Benzene 
is used in the manufacture of dyes and synthetic detergents. Toluene is used 
in making explosives. Manufacturers use xylenes in making plastics and 
synthetic fibers. Aromatics are produced by reforming. 
 
Synthesis gas (SynGas) is a mixture of carbon monoxide and hydrogen, 
and is used to make the petrochemicals ammonia and methanol. Ammonia 
is used in making fertilizers and explosives, where methanol serves as a 
source for other chemicals.  
 
Figure 23. Petrochemical tree: feedstock and primary petrochemicals 
 
The primary petrochemicals are not end products, but form building blocks 
for a wide range of materials. Therefore, each primary petrochemical gives 
name to a chain of reactions leading to those materials. There are almost 
200 petrochemicals that can be described this way. There are more 

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processes than end products, as each product may require multiple steps, 
so an exhaustive list would not fit within this book. Instead, we will focus on 
the main chains, properties and uses of the most important compounds and 
a few key processes for this overview. 
 
Many of these processes are based on polymerization, which means that it 
is based on processes that first form monomers then let these bind together 
to form polymers as long chains or a three dimensional network. Compounds 
whose names start with “poly” are generally polymers, but many other trade 
names, such as nylon which is a generic name for a family of polyamides, 
are polymers. 
 
Petrochemicals are often made in clusters of plants in the same area. These 
plants are often operated by separate companies, and this concept is known 
as  integrated manufacturing. Groups of related materials are often used in 
adjacent manufacturing plants, to use common infrastructure and minimize 
transport. 
 
WST - Exxon Singapore Petrochemical Complex 
 
7.1 Aromatics 
Aromatics, so called because of their distinctive perfumed smell, are a group 
of hydrocarbons that include benzene, toluene and the xylenes. These are 
basic chemicals used as starting materials for a wide range of consumer 

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products. Almost all aromatics come from crude oil, although small quantities 
are made from coal. 
7.1.1 Xylene and polyester chain