Chemistry Reference
In-Depth Information
ETHYLENE DERIVATIVES
E
THYLBENZENE
AND
S
TYRENE
CH
CH
2
CH
2
CH
3
catalyst
catalyst
+
CH
2
=
CH
2
+ H
2
styrene
benzene
ethylbenzene
This is a two-step reaction. The ethylbenzene is isolated in the first step and
then contacted with a different catalyst at high temperature in the second
step. Ethylbenzene and styrene plants are usually built together.
Uses
Ethylbenzene is used primarily to make styrene. Styrene is used
to make polystyrene, a low-cost and versatile polymer. It is
also copolymerized with other vinyl monomers to make rubber
(SBR) and moldable plastics (ABS).
Suppliers
Lyondell, Chevron, BP Amoco, Dow, Sterling Chemicals, Nova
Chemicals.
About half of the styrene produced is polymerized to
polystyrene
, an easily
molded, low-cost thermoplastic that is somewhat brittle. Foamed polystyrene
can be made by polymerizing it in the presence of low-boiling hydrocarbons,
which cause bubbles of gas in the solid polymer after which it migrates out
and evaporates. Modification and property enhancement of polystyrene-
based plastics can be readily accomplished by
copolymerization
with other
substituted ethylenes (vinyl monomers); for example, copolymerization with
butadiene produces a widely used synthetic rubber.
