Benzene (data page)

This page provides supplementary chemical data on benzene.

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 such as SIRI, and follow its directions. MSDS for benzene available at AMOCO.

Structure and properties

Structure and properties
Index of refraction, nD 1.5011 at 20°C
Abbe number ?
Dielectric constant, εr (2.274 – 0.0020ΔT) ε0
(ΔT = T – 25 °C)
Bond strength ?
Bond length 1.39 Å C-C[1]
Bond angle 120°C–C–C
120° H–C–C
Magnetic susceptibility ?
Surface tension 28.88 dyn/cm at 25°C
Viscosity[2]
0.7528 mPa·s at 10°C
0.6999 mPa·s at 15°C
0.6516 mPa·s at 20°C
0.6076 mPa·s at 25°C
0.5673 mPa·s at 35°C
0.4965 mPa·s at 40°C
0.4655 mPa·s at 45°C
0.4370 mPa·s at 50°C
0.4108 mPa·s at 55°C
0.3867 mPa·s at 60°C
0.3644 mPa·s at 65°C
0.3439 mPa·s at 70°C
0.3250 mPa·s at 75°C
0.3075 mPa·s at 80°C

Thermodynamic properties

Phase behavior
Triple point 278.5 K (5.4 °C), 4.83 kPa
Critical point 562 K (289 °C), 4.89 MPa
Std enthalpy change
of fusion, ΔfusHo		 9.9 kJ/mol at 5.42 °C
Std entropy change
of fusion, ΔfusSo		 35.5 J/(mol·K) at 5.42 °C
Std enthalpy change
of vaporization, ΔvapHo		 33.9 kJ/mol at 25°C
30.77 kJ/mol at 80.1°C
Std entropy change
of vaporization, ΔvapSo		 113.6 J/(mol·K) at 25°C
87.1 J/(mol·K) at 80.1°C
Solid properties
Std enthalpy change
of formation, ΔfHosolid		 ? kJ/mol
Standard molar entropy,
Sosolid		 45.56 J/(mol K)
Heat capacity, cp 118.4 J/(mol K) at 0°C
Liquid properties
Std enthalpy change
of formation, ΔfHoliquid		 +48.7 kJ/mol
Standard molar entropy,
Soliquid		 173.26 J/(mol K)
Enthalpy of combustion, ΔcHo –3273 kJ/mol
Heat capacity,[2] cp 134.8 J/(mol K)
Gas properties
Std enthalpy change
of formation, ΔfHogas		 +82.93 kJ/mol
Standard molar entropy,[3]
Sogas		 269.01 J/(mol K)
Heat capacity,[2] cp 82.44 J/(mol K) at 25°C
van der Waals' constants[4] a = 1823.9 L2 kPa/mol2
b = 0.1154 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 –36.7(s) –11.5(s) 7.6 26.1 60.6 80.1 103.8 142.5 178.8 221.5 272.3  —

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed. Note: (s) notation indicates equilibrium temperature of vapor over solid, otherwise value is equilibrium temperature of vapor over liquid.

log of Benzene vapor pressure. Uses formula: \scriptstyle \log _{e}P_{mmHg}=\scriptstyle \log _{e}({\frac {760}{101.325}})-8.433613\log _{e}(T+273.15)-{\frac {6281.040}{T+273.15}}+71.10718+6.198413\times 10^{-06}(T+273.15)^{2} obtained from CHERIC[2] Note: yellow area is the region where the formula disagrees with tabulated data above.

Distillation data

Vapor-liquid Equilibrium
for Benzene/Ethanol[5]
P = 760 mm Hg
BP
Temp.
°C		 % by mole ethanol
liquid vapor
70.8 8.6 26.5
69.8 11.2 28.2
69.6 12.0 30.8
69.1 15.8 33.5
68.5 20.0 36.8
67.7 30.8 41.0
67.7 44.2 44.6
68.1 60.4 50.5
69.6 77.0 59.0
70.4 81.5 62.8
70.9 84.1 66.5
72.7 89.8 74.4
73.8 92.4 78.2
    
Vapor-liquid Equilibrium
for Benzene/Methanol[5]
P = 760 mm Hg
BP
Temp.
°C		 % by mole methanol
liquid vapor
70.67 2.6 26.7
66.44 5.0 37.1
62.87 8.8 45.7
60.20 16.4 52.6
58.64 33.3 55.9
58.02 54.9 59.5
58.10 69.9 63.3
58.47 78.2 66.5
59.90 89.8 76.0
62.71 97.3 90.7
    
Vapor-liquid Equilibrium
for Benzene/Acetone[5]
P = 101.325 kPa
BP
Temp.
°C		 % by mole benzene
liquid vapor
57.34 11.7 7.4
57.48 12.8 8.1
57.75 15.1 9.5
59.21 26.7 16.6
59.24 27.0 16.7
60.01 32.7 20.2
60.71 37.3 23.1
61.05 39.8 24.7
61.91 45.0 27.9
62.82 50.2 31.7
63.39 53.4 33.9
63.79 55.4 35.3
64.22 57.2 37.0
64.99 61.3 39.9
67.88 73.0 51.2
70.21 80.7 60.1
72.23 86.1 67.9
    
Vapor-liquid Equilibrium
for Benzene/n-Hexane[5]
P = 760 mmHg
BP
Temp.
°C		 % by mole hexane
liquid vapor
77.6 7.3 14.0
75.1 17.2 26.8
73.4 26.8 37.6
72.0 37.2 46.0
70.9 46.2 54.0
70.0 58.5 64.4
69.4 69.2 72.5
69.1 79.2 80.7
69.0 82.8 83.8
68.9 88.3 88.8
68.8 94.7 95.0
68.8 96.2 96.4

Spectral data

UV-Vis
Ionization potential 9.24 eV (74525.6 cm−1)
S1 4.75 eV (38311.3 cm−1)
S2 6.05 eV (48796.5 cm−1)
λmax 255 nm
Extinction coefficient, ε ?
IR
Major absorption bands[6]
(liquid film)
Wave number transmittance
3091 cm−1 42%
3072 cm−1 49%
3036 cm−1 27%
1961 cm−1 77%
1815 cm−1 70%
1526 cm−1 81%
1479 cm−1 20%
1393 cm−1 84%
1176 cm−1 86%
1038 cm−1 49%
674 cm−1 4%
NMR
Proton NMR (CDCl3, 300 MHz) δ 7.34 (s, 6H)
Carbon-13 NMR (CDCl3, 25 MHz) δ 128.4
Other NMR data  
MS
Masses of
main fragments		  

Safety data

Material Safety Data Sheet for benzene:

Common synonyms None
Physical properties Form: colorless liquid
Stability: Stable, but very flammable
Melting point: 5.5 C
Water solubility: negligible
Specific gravity: 0.87
Principal hazards *** Benzene is a carcinogen (cancer-causing agent).
*** Very flammable. The pure material, and any solutions containing it, constitute a fire risk.
Safe handling Benzene should NOT be used at all unless no safer alternatives are available.
If benzene must be used in an experiment, it should be handled at all stages in a fume cupboard.
Wear safety glasses and use protective gloves.
Emergency Eye contact: Immediately flush the eye with plenty of water. Continue for at least ten minutes
and call for immediate medical help.
Skin contact: Wash off with soap and water. Remove any contaminated clothing. If the skin
reddens or appears damaged, call for medical aid.
If swallowed: Call for immediate medical help.
Disposal It is dangerous to try to dispose of benzene by washing it down a sink, since it is toxic, will cause environmental damage
and presents a fire risk. It is probable that trying to dispose of benzene in this way will also break local
environmental rules. Instead, retain in a safe place in the laboratory (well away from any source of ignition)
for disposal with other flammable, non-chlorinated solvents.
Protective equipment Safety glasses. If gloves are worn, PVA, butyl rubber and viton are suitable materials.

References

  1. ↑ Brown, LeMay, Bursten (2006). Chemistry: The Central Science. Upper Saddle River, NJ: Pearson Education. p. 1067. ISBN 0-13-109686-9.
  2. 1 2 3 4 "Pure Component Properties" (Queriable database). Chemical Engineering Research Information Center. Retrieved 12 May 2007.
  3. ↑ "ETP Entropy of Benzene" (Queriable database). Dortmund Data Bank. Retrieved 7 Oct 2011.
  4. ↑ Lange's Handbook of Chemistry 10th ed, pp 1522-1524
  5. 1 2 3 4 "Binary Vapor-Liquid Equilibrium Data" (Queriable database). Chemical Engineering Research Information Center. Retrieved 12 May 2007.
  6. ↑ "Spectral Database for Organic Compounds" (Queriable database). Advanced Industrial Science and Technology. Retrieved 10 June 2007.

Except where noted otherwise, data relate to standard ambient temperature and pressure.

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