Paraxylene: Characteristics
The freezing point that forces heated tanks
What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.PX is sold on purity because PTA catalysts and polymer colour are sensitive to other xylenes, ethylbenzene and sulphur. Freezing point decides handling.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Purity | at least 99.7% (ASTM D5136 type specification, indicative) | PTA quality and yield | indicative |
| Freezing point | 13.3 C | Needs heated storage and shipping in winter; enables crystallisation route | standard data |
| Boiling point | 138.4 C (close to m-xylene at 139.1 C) | Cannot be separated by simple distillation | standard data |
Commercial grades
- PX 99.7% (standard PTA feed)
- PX 99.8% (premium)