A.k.a. p-xylene, p-methyltoluene, 4-methyltoluene, 1,4-dimethylbenzene, or PX. A high volume chemical intermediate that is an isomer of xylene.  Primarily used as a raw material in the manufacture of terephthalic acid (TPA), purified terephthalic acid (PTA), and dimethyl-terephthalate (DMT) used to produce polyester. Chevron Phillips Chemical is one of the largest marketers of high purity paraxylene in the world.