P-Xylene
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- The correct title of this article is p-Xylene. The initial letter is shown capitalized due to technical restrictions.
p-Xylene | |
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General | |
Common name | p-Xylene |
Systematic name | 1,4-Dimethylbenzene |
Other names | p-Xylol Paraxylene |
Chemical formula | C8H10 |
Molecular mass | 106.16 g/mol |
Appearance | Clear, colorless liquid colorless crystalline solid |
CAS number | 106-42-3 |
Properties | |
Density and phase | 0.87 g/cm³, liquid |
Solubility in water | Insoluble |
Melting point | 12-13 °C |
Boiling point | 138 °C |
Critical temperature | 343 °C (616 K) |
Viscosity | 0.34 cP at 30°C/ 86°F |
Dipole moment | 0.07 D |
Hazards | |
MSDS | External MSDS |
Main hazards | Flammable; Harmful; Irritant |
NFPA 704 | |
Flash point | 27 °C/ 80.6 °F |
R-phrases | R10, R10, R11, R38 |
S-phrases | S25 |
RTECS number | ZE2625000 |
Supplementary data page | |
Structure & properties | n, εr, etc. |
Thermodynamic data | Phase behaviour Solid, liquid, gas |
Spectral data | UV, IR, NMR, MS |
Related compounds | |
Related aromatic hydrocarbons |
benzene toluene |
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references |
p-Xylene is an aromatic hydrocarbon, based on benzene with two methyl substituents. The “p” stands for para, identifying the location of the methyl groups as across from one another.
It is an isomer of xylene. Other isomers include o-xylene and m-xylene. p-Xylene is used on a large scale for the manufacture of terephthalic acid for polyester. Its polymer is known as parylene.
Global demand for p-xylene is around 32 million tonnes in 2006, essentially all of this manufacture going into polyester production for fibres and films (eg PET soft drinks bottles).
p-Xylene includes several molecular structures; only a few are used commercially. It has a variety of uses. In electronics, it is vapor-deposited at low pressure onto circuit boards as a thin, even conformal coating. p-Xylene coating has very high electrical resistivity and resists moisture penetration. It is used as a dielectric in certain high-performance capacitors for precision measurement. It has uses in preserving archival paper.
[edit] See also
[edit] External links
- Parylene Specifications and Properties
- Parylene Properties & Characteristics
- Links to external chemical sources