DESIGNATIONS
CAS No.: 108-95-2
Registry name: Phenol
Chemical name: Phenol
Synonyms, Trade names: Carbolic acid, hydroxybenzene, monohydroxybenzene, oxybenzene, phenic acid, phenyl hydrate, phenyl hydroxide, phenyl acid
Chemical name (German): Phenol, Karbolsäure, Hydroxybenzol
Chemical names (French): Phénol, acide carbolique, acide phénique, benzénol, phénol ordinaire
Appearance: colourless/whitish red substance or colourless melt; sweetish odour
BASIC CHEMICAL AND PHYSICAL DATA
Empirical formula: | C6H6O |
Rel. molecular mass: | 94.11 g |
Density: | 1.07 g/cm3 at 20°C |
Relative gas density: | 3.24 |
Boiling point: | 181.75°C |
Melting point: | 40.8°C |
Vapour pressure: | 0.2 hPa at 20°C; 3.5 hPa at 50°C; 54 hPa at 100 °C |
Flash point: | 82°C |
Ignition temperature: | 595°C |
Explosion limit: | 1.3 - 9.5 Vol% |
Odour threshold: | 0.18 mg/m3 = 0.046 ppm |
Solvolysis/solubility: | in water: 82 g/l |
readily soluble in alcohol, ether, chloroform, fats and ethereal oils | |
Conversion factors: | 1 ppm = 3.91 mg/m3 |
1 mg/m3 = 0.26 ppm |
ORIGIN AND USE
Usage:
Phenol is used to make synthetic resins, dyes, pharmaceuticals,
pesticides, synthetic tanning agents, perfumes, lubricating oils
and solvents.
Origin/derivation:
In the phenols group, cresols and the parent compound itself are
the most important compounds as well as thymol, naphthols,
phenolphthalein, trichlorophenol and pentachlorophenol. Natural
compounds such as pyrocatechol, guaiacol and their derivatives
are not toxic. A well-known pyrocatechol derivative is
adrenaline. Phenol naturally occurs in pine wood and pine
needles, in the urine of herbivores (phenol sulphate) and in coal
tar. Monohydric phenols provide numerous natural scents (e.g.
vanillin, thymol, carvacrol, zingiverone (in ginger),
salicylaldehyde). Amongst the synthetic multivalent phenols
hexachlorophene is particularly toxic.
Phenol is obtained from the distillation of coal tar (according to RÖMPP, (1983) 1 t of coal gives approx.0.25 kg of phenol). Synthetic production has however become predominant and involves the decomposition of cumene hydroperoxide with acetone forming as by-product. Some use is still made of the preparation from benzene using benzene sulphonic acid or chlorobenzene.
Emissions are produced by the incomplete combustion of gasoline and coal tar, in the waste water from coking plants and as metabolites in the photolysis of benzene and chlorobenzene.
Production figures:
Annual production (worldwide): | 3 million t/a | (RIPPEN, 1989) |
Annual production (D): | 250,000 t/a | (RIPPEN, 1989) |
Annual production (USA, 1988): | 1,600,000 t/a | (RIPPEN, 1989) |
Toxicity
Humans: | 1 g can be fatal | acc. RIPPEN, 1989 |
Mammals: | ||
Rat: | LD50 414-530 mg/kg, oral | acc. RIPPEN, 1989 |
Rat: | LD50 670 mg/kg, dermal | acc. RIPPEN, 1989 |
Rabbit: | LD50 400-600 mg/kg, oral | acc. RIPPEN, 1989 |
Rabbit: | LD50 850 mg/kg, dermal | acc. RIPPEN, 1989 |
Cat: | LD50 100 mg/kg, oral | acc. RIPPEN, 1989 |
Dog: | LD50 500 mg/kg, oral | acc. RIPPEN, 1989 |
Aquatic organisms: | ||
Pimephales promelas: | LC50 24-68 mg/l | acc. RIPPEN, 1989 |
Leuciscus idus melanotus: | LC50 25 mg/l (48h) | acc. RIPPEN, 1989 |
Lepomis macrochirus: | LC50 24 mg/l (96h) | acc. RIPPEN, 1989 |
Daphnia: | LC50 12 mg/l (48h) | acc. RIPPEN, 1989 |
Scenedesmus quadricauda: | EC0 7.5-40 mg/l | acc. RIPPEN, 1989 |
Microcystis aeruginosa: | EC0 4.6 mg/l | acc. RIPPEN, 1989 |
Toxicity data for various phenol compounds can be found in DFG, 1982, volume II: phenols.
Characteristic effects:
Humans/mammals: Vapours and liquids are toxic and easily absorbed through the skin. Once inhaled, vapours corrode the respiratory tract and the lungs. Severe burns result from the liquid coming into contact with skin and eyes (phenol is a powerful protoplasmic poison). Long-term exposure paralyzes the central nervous system and damages the kidneys and the lungs. Paralysis may cause death. Accompanying symptoms are headaches, tinnitus, dizziness, stomach and intestinal irritations, drowsiness, collapse, poisoning, loss of consciousness, irregular breathing, apnoea, heart failure and in some cases spasms. HORN (1989) classes phenol as having a teratogenic and carcinogenic effect. According to the Ames-test, phenol has no mutagenic potential.
Damage caused by oral intake is usually prevented by the alarming odour and taste (Refer also to "cresol" and "chlorophenol" information sheets)
Plants: Passive permeability impaired; growth inhibited.
ENVIRONMENTAL BEHAVIOUR
Water:
Phenol is heavier than water and sinks to the bottom. It
dissolves slowly and continues to form toxic solutions even when
diluted. Because of its considerable toxicity in water, phenol is
listed in water hazard class 2 in Germany.
Air:
Vapours are heavier than air and form explosive mixtures when
exposed to heat. The oxidation of phenol in air is accelerated by
light or impurities with a catalytic effect.
Soil:
There is only limited accumulation because of the microbial
degradation in the soil (aerobic or anaerobic). The accumulation
level depends on the presence of clay minerals (great affinity
with aluminium oxide).
Degradation, decomposition products:
The biological degradability of natural phenols is generally
very good with the result that there is scarcely any accumulation
in plants or animals. Aerobic bacterial degradation involves
complete breakdown to carbon dioxide. Condensation to humic acids
may be found in soil. The degradability of synthetic phenols is
less pronounced as many phenols are toxic to microorganisms.
Toxicity increases with the number of chlorine or nitrogen atoms
in the phenols. "Pentachlorophenol" is thus the most
toxic compound of the chlorophenol group and trinitrophenol
(picric acid) is the most poisonous compound within the
nitrophenol group.
There is roughly 90% degradation in surface water in approx. 7 days (standing water); the same rate is achieved in soil in roughly 1 day depending on microflora and concentration (RIPPEN, 1989); complete degradation in earthy suspensions takes more than two days.
Phenol metabolites can also be extremely toxic: Incomplete combustion of 2,4,5-trichlorophenol may cause the formation of TCDD (dioxin). Biodegradation generally produces acetic acid and CO2 by way of pyrocatechol, o-quinone and dicarboxylic acids (RIPPEN, 1982).
Phenol is excreted from the organism with the urine after oxidation or conjugation with sulphuric or gluconic acid.
Food chain:
There is only little accumulation in foodstuffs. Smokers are at
risk since cigarette smoke contains phenols. The presence of
phenol in groundwater causes polluted drinking water which may
not be used because of its evil taste.
ENVIRONMENTAL STANDARDS
Medium/acceptor | Sector | Country/organ. | Status | Value | Cat. | Remarks | Source |
Water: | Drinkw | EC | (L) |
0.0005 g/m3 |
Maximum concentration | acc. LAU-BW, 1989 | |
Drinkw | USA | 0.001 mg/l |
In State of Illinois | acc. WAITE, 1984 | |||
Drinkw | USA | 0.02 mg/l |
In State of Iowa | acc. WAITE, 1984 | |||
Surface | D | G |
0.005 g/m3 |
4) | acc. LAU-BW, 1989 | ||
Surface | D | G |
0.01 g/m3 |
5) | acc. LAU-BW, 1989 | ||
Groundw | NL | G |
0.2 m g/l |
Reference | acc. TERRA TECH, 6/94 | ||
Groundw | NL | L |
2000 m g/l |
Intervention | acc. TERRA TECH, 6/94 | ||
Waste water | CH | (L) |
0.005 g/m3 |
6) | acc. LAU-BW, 1989 | ||
Waste water | CH | (L) |
0.05-0.20 g/m3 |
7) | acc. LAU-BW, 1989 | ||
Waste water | D | G |
100 g/m3 |
Guideline8) | acc. LAU-BW, 1989 | ||
Soil: | GB | G |
0-0.1 mg/kg |
Not contaminated | acc. LAU-BW, 1989 | ||
GB | G |
5-50 mg/kg |
Contaminated soil | acc. LAU-BW, 1989 | |||
GB | G |
> 250 mg/kg |
Heavily contaminated | acc. LAU-BW, 1989 | |||
NL | G |
0.05 mg/kg |
Reference | acc. TERRA TECH, 6/94 | |||
NL | L |
40 mg/kg |
Intervention | acc. TERRA TECH, 6/94 | |||
Air: | Emiss. | D | L |
20 mg/m3 |
mass flow > 0.1 kg/h | acc. TA Luft, 1986 | |
BG | (L) |
0.01 mg/m3 |
30 min, 24 h8) 9) | acc. STERN, 1986 | |||
CS | (L) |
0.1 mg/m3 |
30 min, 24 h | acc. STERN, 1986 | |||
D | L |
0.2 mg/m3 |
MIK | Long-time value | acc. BAUM, 1988 | ||
D | L |
0.6 mg/m3 |
MIK | Short-time value | acc. BAUM, 1988 | ||
DDR | (L) |
0.01 mg/m3 |
Short-time value | acc. HORN, 1989 | |||
DDR | (L) |
0.003 mg/m3 |
Long-time value | acc. HORN, 1989 | |||
H | (L) |
0.01 mg/m3 |
30 min, 24 h8) 9) | acc. STERN, 1986 | |||
H | (L) |
0.6 mg/m3 |
30 min10) | acc. STERN, 1986 | |||
IL | (L) |
0.02 mg/m3 |
20 min | acc. STERN, 1986 | |||
IL | (L) |
0.01 mg/m3 |
24 h | acc. STERN, 1986 | |||
RO | (L) |
0.1 mg/m3 |
30 min | acc. STERN, 1986 | |||
RO | (L) |
0.03 mg/m3 |
24 h | acc. STERN, 1986 | |||
SU | (L) |
0.01 mg/m3 |
30 min, 24 h8) 9) | acc. STERN, 1986 | |||
TJ | (L) |
0.02 mg/m3 |
60 min | acc. STERN, 1986 | |||
Workp | D | L |
19 mg/m3 |
MAK | DFG, 1989 | ||
Workp | DDR | L |
20 mg/m3 |
acc. HORN, 1989 | |||
Workp | SU | (L) |
0.3 mg/m3 |
PDK | acc. SORBE, 1989 | ||
Workp | USA | (L) |
19 mg/m3 |
TWA | ACGIH, 1986 | ||
Workp | USA | (L) |
38 mg/m3 |
STEL | ACGIH, 1986 |
Notes:
1) Assessment value for soil and groundwater contamination, A value = no impact
2) Assessment value for soil and groundwater contamination, B value = further investigations necessary
3) Assessment value for soil and groundwater contamination, C value = rehabilitation needed
4) Impact limit up to which drinking water can be produced solely by natural methods
5) Impact limit up to which drinking water can be produced using currently tried and tested chemical/physical methods
6) "Swiss quality goal" used as basis for assessing surface water and drinking water supply
7) Limit value for introduction of sewage into flowing water
8) Guideline for requirements to be satisfied by sewage introduced into public sewage systems in Baden-Württemberg
9) Areas in need of protection
10) Areas in need of special protection
11) 0ther areas not in need of special protection
Comparison/reference values
Medium/origin | Country | Value | Source |
Water: | |||
Sewage treatment plant (inflow/discharge) | D, USA | 2-20 ppb | acc. RIPPEN, 1989 |
River water | USA | 10-100 ppb | acc. RIPPEN, 1989 |
Surface water (1977) | J | < 10 ppb (n=9) | acc. RIPPEN, 1989 |
Danube (1972) | D | 0.01-1 ppb | acc. RIPPEN, 1989 |
Drinking water | D | 6-20 ppt | acc. RIPPEN, 1989 |
Soil/sediment: | |||
Sediment (1977) | J | 30-40 ppb (n=3) | acc. RIPPEN, 1989 |
Air: | |||
Outdoor concentration | DDR | 12 µg/m3 | acc. HORN, 1989 |
City (1979) | J | 0.5-1.0 ppb | acc. RIPPEN, 1989 |
City (1973) | USA | 15-91 ppt | acc. RIPPEN, 1989 |
Paris (1977), (n=7) | F | 0.17-2.1 ppb (2h values) | acc. RIPPEN, 1989 |
Motor vehicle emissions | 1.3-1.5 ppm | acc. RIPPEN, 1989 | |
Tobacco smoke | 300-500 ppm | acc. RIPPEN, 1989 | |
Humans: | |||
Excretion, urine: | 0.02-6.6 mg/kg/d | acc. RIPPEN, 1989 |
Assessment/comments
There is urgent need for reduced emissions since synthetic phenols are more toxic than natural phenols. The risk of skin contact and inhalation when handling phenol needs particular attention.
(Refer also to "chlorophenols" and "cresols" information sheets).