Benzene

  • Benzol
  • Cyclohexatriene
  • Phenyl hydride
  • Benzine
Formula
C6H6
Structure
Description
Clear, colorless liquid with a characteristic, aromatic hydrocarbon odor.
Uses
Manufacture of industrial chemicals such as polymers, detergents, pesticides pharmaceuticals, dyes, plastics, resins. Solvent for waxes, resins, oils, natural rubber, etc. Gasoline additive use as solvent is now discouraged.

Registry Numbers and Inventories.
CAS
71-43-2
EC (EINECS/ELINCS)
200-753-7
EC Index Number
601-020-00-8
EC Class
Highly flammable; Carcinogenic Category 1; Toxic
R 45 11 48/23/24/25
RTECS
CY1400000
RTECS class
Agricultural Chemical and Pesticide; Tumorigen; Drug; Mutagen; Reproductive Effector; Human Data; Primary Irritant
UN (DOT)
1114
Merck
13,1066
Beilstein/Gmelin
969212
Beilstein Reference
4-05-00-00583
RCRA
U019
EPA OPP
600019
Swiss Giftliste 1
G-1236
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C6H6
Formula mass
78.11
Melting point, °C
5.5
Boiling point, °C
80.1
Vapor pressure, mmHg
75 (20 C)
Vapor density (air=1)
2.8
Saturation Concentration
9.9% (98700 ppm) at 20 C; 12.5% (approximately 125300 ppm) at 25 C (calculated)
Evaporization number
3 (diethyl ether = 1)
Odor Threshold Odor threshold 4.9 mg/m3
Critical temperature
288.9
Critical pressure
48.6
Density
0.878 g/cm3 (20 C)
Solubility in water
1.8 g/L
Viscosity
0.604 cp @ 25C
Surface tension
28.22 g/s2 @ 25 C
Refractive index
1.50108 (20 C)
Dipole moment
2.27 D
Dielectric constant
2.3 (20 C)
Partition coefficient, pKow
2.13
Heat of fusion
9.9 kJ/mol
Heat of vaporization
33.83 kJ/mol
Heat of combustion
-3275 kJ/mol

Hazards and Protection.
Storage
Keep away from heat, sparks, and flame. Keep away from sources of ignition. Store in a tightly closed container. Keep from contact with oxidizing materials. Store in a cool, dry, well-ventilated area away from incompatible substances.
B2 D2A D2B
Handling
Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Ground and bond containers when transferring material. Do not breathe dust, vapor, mist, or gas. Do not get in eyes, on skin, or on clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Keep container tightly closed. Avoid contact with heat, sparks and flame. Do not ingest or inhale. Use only in a chemical fume hood. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator's use.
Small spills/leaks
Use water spray to dilute spill to a non-flammable mixture. Avoid runoff into storm sewers and ditches which lead to waterways. Use water spray to disperse the gas/vapor. Remove all sources of ignition. Absorb spill using an absorbent, non-combustible material such as earth, sand, or vermiculite.
Disposal code
9
Stability
Stable under normal temperatures and pressures.
Incompatibilities
Chlorine, oxygen, ozone, permanganates, sulfuric acid, peroxides, perchlorates, nitrating agents, nitric acid, chromic acid anhydride, chromium trioxide, iodine pentafluoride, iodine heptafluoride, dioxygenyl tetrafluoroborate, dioxygen difluoride + hydrogen fluoride, sodium peroxide, uranium hexafluoride, bromine pentafluoride, chlorine trifluoride, nitryl perchlorate, aresenic pentafluoride, potassium methoxide, permanganic acid, peroxodisulfuric acid, liquid oxygen, peroxomonosulfuric acid, metal perchlorates, strong oxidizing agents.
Decomposition
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.

Fire.
Flash Point,°C
-11
Autoignition, °C
498
Upper exp. limit, %
7.1
Lower exp. limit, %
1.3
Fire fighting
Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use foam, dry chemical, or carbon dioxide. Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear.
Fire potential
Very flammable. Combustion imminent.
Hazards
Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back.
Combustion products
Fire will produce irritating, corrosive and/or toxic gases.
Health
2
 
Flammability
3
 
 
Reactivity
0
 

Health.
Exposure limit(s)
TLV: 10 ppm; 32 mg/m3 (as TWA) A2 (ACGIH 1991-1992). OSHA PEL: 1910.1028 TWA 1 ppm ST 5 ppm See Appendix F NIOSH REL: Ca TWA 0.1 ppm ST 1 ppm See Appendix A NIOSH IDLH: Potential occupational carcinogen 500 ppm.
Carcinogin
O, G-A1, I-1, N-1, CP65
Poison_Class
1*
Exposure effects
Possible cancer hazard based on tests with laboratory animals. Prolonged or repeated exposure may cause adverse reproductive effects. May cause bone marrow abnormalities with damage to blood forming tissues. May cause anemia and other blood cell abnormalities. Chronic exposure has been associated with an increased incidence of leukemia and multiple myelomas. Immunodepressive effects have been reported. Animal studies have reported fetotoxicity (growth retardation) and teratogenicity (exencephaly, angulated ribs, dilated brain ventricles).
   Ingestion
Aspiration hazard. May cause central nervous system depression, characterized by excitement, followed by headache, dizziness, drowsiness, and nausea. Advanced stages may cause collapse, unconsciousness, coma and possible death due to respiratory failure. May cause effects similar to those for inhalation exposure. Aspiration of material into the lungs may cause chemical pneumonitis, which may be fatal.
   Inhalation
Causes respiratory tract irritation. May cause adverse central nervous system effects including headache, convulsions, and possible death. May cause drowsiness, unconsciousness, and central nervous system depression. Central nervous system effects may include confusion, ataxia, vertigo, tinnitus, weakness, disorientation, lethargy, drowsiness, and finally coma. Exposure may lead to irreversible bone marrow injury. Exposure may lead to aplastic anemia. May be absorbed through the lungs.
   Skin
Causes moderate skin irritation. May be absorbed through the skin in harmful amounts. Direct contact with the liquid may cause erythema and vesiculation. Prolonged or repeated contact has been associated with the development of a dry scaly dermatitis or with secondary infections.
   Eyes
Causes severe eye irritation. May cause slight transient injury.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Possible aspiration hazard. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
   Skin
Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
   Eyes
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.

Transport.
UN number
1114
Response guide
Hazard class
3
Packing Group
II
 
USCG CHRIS Code
BNZ
 
32 Aromatic hydrocarbons
HS Code
2902 20 00
 
Std. Transport #
4908112
 
IMO Chemical Code
17
IMO Pollution Category
C
IMO Hazard code
S/P