Aniline (data page)

This page provides supplementary chemical data on aniline.

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.

• Mallinckrodt Baker
• Science Stuff

Structure and properties

Structure and properties
Index of refraction, nD	1.5863 at 20 °C
Abbe number	?
Dielectric constant,[1] εr	6.89 ε0 at 20 °C
Bond strength	?
Bond length	?
Bond angle	?
Magnetic susceptibility	?
Surface tension[2]	44.0 dyn/cm at 10 °C 42.9 dyn/cm at 20 °C 24.4 dyn/cm at 180 °C
Viscosity[3]	6.023 mPa·s at 12 °C 4.467 mPa·s at 20 °C 2.92 mPa·s   at 22 °C 1.555 mPa·s at 60 °C

Thermodynamic properties

Phase behavior
Triple point	267.13 K (–6.02 °C), ? Pa
Critical point	698.8 K (425.7 °C), 4890 kPa
Std enthalpy change of fusion, ΔfusHo	10.54 kJ/mol
Std entropy change of fusion, ΔfusSo	39.57 J/(mol·K) at –6.3 °C
Std enthalpy change of vaporization, ΔvapHo	55.83 kJ/mol at 25 °C 42.44 kJ/mol at 184.1 °C
Std entropy change of vaporization, ΔvapSo	? J/(mol·K)
Solid properties
Std enthalpy change of formation, ΔfHosolid	? kJ/mol
Standard molar entropy, Sosolid	? J/(mol K)
Heat capacity, cp	? J/(mol K)
Liquid properties
Std enthalpy change of formation, ΔfHoliquid	31 kJ/mol
Standard molar entropy, Soliquid	191. J/(mol K)
Enthalpy of combustion, ΔcHoliquid	–3393 kJ/mol
Heat capacity, cp	193.7 J/(mol K) at 25 °C
Gas properties
Std enthalpy change of formation, ΔfHogas	87 kJ/mol
Standard molar entropy, Sogas	? J/(mol K)
Heat capacity,[4] cp	148.7 J/(mol K) at 25 °C
van der Waals' constants[5]	a = 2685 L2 kPa/mol2 b = 0.1369 liter per mole

Vapor pressure of liquid

P in mm Hg		1	10	40	100	400	760	1520	3800	7600	15200	30400	45600
T in °C		34.8	69.4	96.7	119.9	161.9	184.4	212.8	254.8	292.7	342.0	400.0	—

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.

log₁₀ of Aniline vapor pressure. Uses formula: ${\displaystyle \scriptstyle \log _{e}P_{mmHg}=}$${\displaystyle \scriptstyle \log _{e}({\frac {760}{101.325}})-22.11315\log _{e}(T+273.15)-{\frac {13079.73}{T+273.15}}+166.0812+1.233275\times 10^{-5}(T+273.15)^{2}}$ obtained from CHERIC^[4]

Distillation data

See also:

• m-xylene (data page)
• p-xylene (data page)

Vapor-liquid Equilibrium for Aniline/Water[6] P = 745 mm Hg BP Temp. °C  % by mole water liquid vapor 98.5 96.5 101 24.7 94.8 105 20.0 94.3 109.8 15.3 92.4 115.8 11.7 89.3 121 9.3 86.2 126 7.6 81.6 131 5.9 75.9 140 4.25 70.8 152 2.50 60.5 160 1.70 48.7 168 1.05 34.1

Vapor-liquid Equilibrium for Aniline/n-hexane[6] P = 101.325 kPa BP Temp. °C  % by mole hexane liquid vapor 150.2 1.50 62.50 136.4 2.50 76.00 116.0 5.30 88.70 90.0 11.00 96.00 79.5 16.85 97.66 75.7 20.99 98.07 74.1 27.35 98.31 73.25 37.90 98.42 73.20 52.00 98.62 73.15 71.46 98.78 72.15 81.26 98.93 71.50 86.50 99.06 70.70 90.93 99.16 69.80 95.32 99.36 69.10 97.86 99.61

Spectral data

UV-Vis
Ionization potential	7.72(62281)   eV(cm−1)
λmax	230 nm (E2-band)[7] 280 nm (B-band)[7]
Extinction coefficient, ε	8 600 (E2-band)[7] 1 430 (B-band)[7]
IR
Major absorption bands[8]	(liquid film) Wave number transmittance 3663 cm−1 77% 3429 cm−1 32% 3354 cm−1 20% 3214 cm−1 44% 3088 cm−1 62% 3072 cm−1 55% 3037 cm−1 38% 3010 cm−1 67% 2930 cm−1 81% 2904 cm−1 79% 2640 cm−1 79% 2627 cm−1 81% 1929 cm−1 77% 1839 cm−1 79% 1705 cm−1 77% 1621 cm−1 7% 1601 cm−1 5% 1557 cm−1 70% 1525 cm−1 66% 1496 cm−1 4% 1467 cm−1 34% 1332 cm−1 74% 1312 cm−1 57% 1277 cm−1 25% 1176 cm−1 32% 1154 cm−1 68% 1053 cm−1 77% 1028 cm−1 64% 996 cm−1 60% 881 cm−1 53% 754 cm−1 8% 693 cm−1 10% 620 cm−1 47% 529 cm−1 50% 504 cm−1 18%
NMR
Proton NMR
Carbon-13 NMR
Other NMR data
MS
Masses of main fragments

UV Absorbance Spectroscopy of Aniline

Aniline is a benzenoid compound. The NH₂ group attached to the benzene ring means that there is a lone pair of electrons that can enter into conjugation with the benzene ring resulting in delocalization in the aniline.

Aniline absorbs in the K (220 - 250 nm) and the B (250 - 290 nm) bands exhibited by benzenoid compounds. The K and B bands arise from π to π* transitions as a result of the a group containing multiple bond being attached to the benzene ring. When dissolved in ethanol, λ_max for aniline is 230 nm, but in dilute aqueous acid λ_max is 203 nm. In the latter case the anilinium cation is formed and the lone pair is no longer available for conjugation with the benzene ring. Consequently, the absorption of the molecule shifts to the lower λ_max value and behaves like benzene.

Regulatory data

Regulatory data
Flash point	70 °C
RTECS	?
Autoignition temperature	615 °C