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 recommended to seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source such as SIRI, and follow its directions. MSDS for benzene is available at AMOCO.
Structure and properties
Structure and properties Abbe number? Dielectric constant, εr (2.274 – 0.0020ΔT) ε0(ΔT = T – 25 °C) Bond energy ? Bond length 1.39 Å C-C Molecular geometry 120 °C–C–C120° H–C–C Surface tension 28.88 dyn/cm at 25 °C Viscosity 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 Std entropy changeof fusion, ΔfusSo 35.5 J/(mol·K) at 5.42 °C Std enthalpy changeof vaporization, ΔvapHo 33.9 kJ/mol at 25 °C30.77 kJ/mol at 80.1 °C Std entropy changeof vaporization, ΔvapSo 113.6 J/(mol·K) at 25 °C87.1 J/(mol·K) at 80.1 °C Solid properties Standard molar entropy,Sosolid 45.56 J/(mol K) Heat capacity, cp 118.4 J/(mol K) at 0 °C Liquid properties Std enthalpy changeof formation, ΔfHoliquid +48.7 kJ/mol Standard molar entropy,Soliquid 173.26 J/(mol K) Enthalpy of combustion, ΔcHo –3273 kJ/mol Heat capacity, cp 134.8 J/(mol K) Gas properties Std enthalpy changeof formation, ΔfHogas +82.93 kJ/mol Standard molar entropy,Sogas 269.01 J/(mol K) Heat capacity, cp 82.44 J/(mol K) at 25 °C van der Waals' constantsLange's Handbook of Chemistry 10th ed, pp. 1522–1524 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.
Distillation data Vapor-liquid Equilibriumfor Benzene/EthanolP = 760 mm Hg BPTemp.°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 Equilibriumfor Benzene/MethanolP = 760 mm Hg BPTemp.°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 Equilibriumfor Benzene/AcetoneP = 101.325 kPa BPTemp.°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 Equilibriumfor Benzene/n-HexaneP = 760 mmHg BPTemp.°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 (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 flammableMelting point: 5.5 CWater solubility: negligibleSpecific 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 minutesand 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 localenvironmental 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 equipmentSafety glasses. If gloves are worn, PVA, butyl rubber and viton are suitable materials.
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