Chemistry Reference
In-Depth Information
XYLENE DERIVATIVES
P
HTHALIC
A
NHYDRIDE
(
FROM
O
-
XYLENE
)
Uses
A little over half of the phthalic anhydride produced is used
for plasticizers in polymers while about 25% is used to
manufacture unsaturated polyester resins. Phthalic
anhydride also finds wide usage in the manufacture of
paints (alkyd resins).
Manufacture
CH
3
CO
catalyst
O
+
O
2
(from air)
CO
CH
3
o-xylene
phthalic anhydride
Suppliers
Aristech Chemical, ExxonMobil, Koppers, Stepan, Sterling
Chemical.
Plasticizers
are very high-boiling liquids that when mixed with polymers
like poly(vinyl chloride) modify the properties of the polymer to produce a
material with added flexibility without losing other desirable properties such
as strength. They are commonly made by reacting phthalic anhydride with
a long-chain alcohol (typically eight carbons).
There are over 400 different commercial alkyd resin formulations based
on phthalic anhydride used in the coatings business. Alkyd resins for paints
are made by reacting phthalic anhydride with a poly-alcohol (usually from
naturally occurring sources rather than synthetic) that contains unreacted
double bonds. The paint dries by the resin crosslinking through reaction of
the double bonds under the influence of oxygen in the air.
