# P-Xylene (data page)

This page provides supplementary chemical data on p-xylene.

## Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions.
* MATHESON TRI-GAS, INC.

## Structure and properties

Structure and properties :
| Index of refraction, n$_D$ | 1.4958 at 20 °C |
| Dielectric constant, ε$_r$ | 2.2 ε$_0$ at 20 °C |
| Surface tension | 29.92 dyn/cm at 5 °C 28.27 dyn/cm at 20 °C 24.2 dyn/cm at 60 °C |
| Viscosity | 0.7385 mPa·s at 10 °C 0.6475 mPa·s at 20 °C 0.5134 mPa·s at 40 °C 0.3519 mPa·s at 80 °C 0.2424 mPa·s at 130 °C |
| Solubility | 0.160 g/L at 0 °C 0.181 g/L at 25 °C 0.22 g/L at 40 °C |

## Thermodynamic properties

Phase behavior :
| Triple point | 286.3 K (13.15 °C), ? Pa |
| Critical point | 617 K (344 °C), 3500 kPa |
| Std enthalpy change of fusion, Δ$_{fus}$H$^o$ | 17.1 kJ/mol |
| Std entropy change of fusion, Δ$_{fus}$S$^o$ | 59.8 J/(mol·K) |
| Std enthalpy change of vaporization, Δ$_{vap}$H$^o$ | 35.7 kJ/mol at 138 °C |
| Std entropy change of vaporization, Δ$_{vap}$S$^o$ | ? J/(mol·K) |
| Solid properties ||
| Std enthalpy change of formation, Δ$_f$H$^o$$_{solid}$ | ? kJ/mol |
| Standard molar entropy, S$^o$$_{solid}$ | ? J/(mol K) |
| Heat capacity, c$_p$ | ? J/(mol K) |
| Liquid properties ||
| Std enthalpy change of formation, Δ$_f$H$^o$$_{liquid}$ | −24.4 kJ/mol |
| Standard molar entropy, S$^o$$_{liquid}$ | 247 J/(mol K) |
| Enthalpy of combustion, Δ$_c$H$^o$ | −4552 kJ/mol |
| Heat capacity, c$_p$ | 181.7 J/(mol K) |
| Gas properties ||
| Std enthalpy change of formation, Δ$_f$H$^o$$_{gas}$ | 1.796000E+04 kJ/kg-mol at 25 °C |
| Standard molar entropy, S$^o$$_{gas}$ | ? J/(mol K) |
| Heat capacity, c$_p$ | 163.2 J/(mol K) at 120 °C |
| van der Waals' constants | a = 3134 L$^2$ kPa/mol$^2$ b = 0.1809 liter per mole |

## Vapor pressure of liquid

| P in mm Hg | P in mm Hg | 1 | 10 | 40 | 100 | 400 | 760 |
| T in °C | T in °C | −8.1 | 27.3 | 54.4 | 75.9 | 115.9 | 138.3 |
Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.

## Distillation data

Vapor-liquid Equilibrium for p-Xylene/o-Xylene P = 26.66 kPa :
| BP Temp. °C | % by mole p-xylene | % by mole p-xylene |
| BP Temp. °C | liquid | vapor |
| 100.1 | 0.0 | 0.0 |
| 99.8 | 4.9 | 5.8 |
| 99.5 | 9.9 | 11.8 |
| 99.0 | 17.4 | 20.7 |
| 98.5 | 25.1 | 29.3 |
| 98.1 | 32.6 | 37.1 |
| 97.6 | 40.6 | 44.9 |
| 97.2 | 48.6 | 53.8 |
| 96.7 | 56.9 | 61.8 |
| 96.2 | 64.9 | 69.6 |
| 95.8 | 73.1 | 77.3 |
| 95.4 | 81.4 | 84.5 |
| 94.9 | 90.7 | 91.6 |
| 94.6 | 95.4 | 96.0 |
| 94.4 | 100.0 | 100.0 |
Vapor-liquid Equilibrium for p-Xylene/m-Xylene P = 26.66 kPa :
| BP Temp. °C | % by mole p-xylene | % by mole p-xylene |
| BP Temp. °C | liquid | vapor |
| 95.30 | 0.0 | 0.0 |
| 95.20 | 8.3 | 8.5 |
| 95.15 | 15.5 | 15.8 |
| 95.05 | 24.3 | 24.9 |
| 95.00 | 33.0 | 33.6 |
| 94.90 | 40.9 | 41.7 |
| 94.85 | 49.0 | 49.7 |
| 94.75 | 57.1 | 57.9 |
| 94.70 | 65.3 | 66.1 |
| 94.60 | 73.8 | 74.3 |
| 94.55 | 81.7 | 82.2 |
| 94.50 | 89.5 | 89.9 |
| 94.45 | 94.8 | 94.8 |
| 94.40 | 100.0 | 100.0 |
Vapor-liquid Equilibrium for p-Xylene/carbon tetrachloride P = 760 mm Hg :
| BP Temp. °C | % by mole carbon tetrachloride | % by mole carbon tetrachloride |
| BP Temp. °C | liquid | vapor |
| 136.4 | 1.7 | 5.9 |
| 131.1 | 6.3 | 21.6 |
| 126.2 | 11.1 | 34.9 |
| 121.8 | 15.7 | 45.3 |
| 117.6 | 20.3 | 53.9 |
| 113.5 | 25.2 | 61.6 |
| 109.8 | 30.1 | 67.9 |
| 106.2 | 35.1 | 73.1 |
| 102.7 | 40.5 | 77.9 |
| 102.2 | 41.3 | 78.7 |
| 98.1 | 48.5 | 83.6 |
| 94.4 | 55.8 | 87.6 |
| 91.1 | 62.9 | 90.8 |
| 88.0 | 70.1 | 93.4 |
| 85.2 | 77.2 | 95.4 |
| 82.6 | 84.0 | 96.9 |
| 80.0 | 91.1 | 98.4 |
| 77.6 | 97.7 | 99.7 |
Vapor-liquid Equilibrium for p-Xylene/Butanone P = 760 mm Hg :
| BP Temp. °C | % by mole butanone | % by mole butanone |
| BP Temp. °C | liquid | vapor |
| 129.45 | 4.8 | 20.8 |
| 125.42 | 7.9 | 31.7 |
| 123.25 | 10.2 | 38.1 |
| 116.80 | 16.1 | 51.1 |
| 112.44 | 21.0 | 59.4 |
| 105.55 | 30.5 | 71.0 |
| 101.15 | 38.7 | 75.5 |
| 95.30 | 50.6 | 85.2 |
| 93.90 | 54.6 | 87.2 |
| 89.45 | 67.0 | 91.7 |
| 86.55 | 77.0 | 94.7 |
| 85.02 | 81.5 | 95.9 |
| 84.58 | 83.1 | 96.2 |
| 80.65 | 97.0 | 994 |
Vapor-liquid Equilibrium for p-Xylene/Aniline P = 745 mm Hg :
| BP Temp. °C | % by mole p-xylene | % by mole p-xylene |
| BP Temp. °C | liquid | vapor |
| 171 | 7.5 | 37.0 |
| 165 | 14.0 | 50.0 |
| 156 | 26.5 | 67.5 |
| 148 | 48.5 | 80.0 |
| 142 | 72.5 | 89.0 |
| 140 | 83.0 | 92.0 |

## Spectral data

UV-Vis :
| Spectrum | |
| λ$_{max}$ | ? nm |
| Extinction coefficient, ε | ? |
| IR ||
| Spectrum | NIST |
| Major absorption bands | 793.94 cm$^{−1}$ |
| NMR ||
| Spectrum | AIST |
| Proton NMR | 2.296, 7.046 |
| Carbon-13 NMR | 134.66, 128.97, 20.90 |
| MS ||
| Spectrum | NIST |
| Masses of main fragments | 106, 91, 77 |
* view
* Except where noted otherwise, data relate to Standard temperature and pressure.
* Reliability of data general note.