| Chemical |
Hydroquinone |
| CAS-number : |
123-31-9 |
| |
| Synonyms : |
| 1,4-Benzenediol |
| 1,4-dihydroksibentseeni |
| 1,4-dihydroxybenzene |
| hydrokinoni |
| p-hydroksifenoli |
| p-hydroxyphenol |
| |
| Sumformula of the chemical : |
| C6H6O2 |
| EINECS-number : |
| 2046178 |
| |
| Uses : |
Photographic developer and oxidation inhibitor; dye
intermediate; medicine; inhibitor of polymerization.
|
| |
| State and appearance : |
Hexagonal prisms.
Light-tan, light-gray or colorless crystals.
|
| |
| Odor : |
Sweet taste.
|
| |
| Molecular weight : |
110.12 |
| |
| Spesicif gravity (water=1) : |
| 1.3 |
at 20 °C |
| |
| Vapor pressure, mmHg : |
| 4 |
150°C |
| 0.0000015 |
at 24 °C, IUCLID 1996 |
| 0.00067 |
at 25 °C, estrapolated, HSDB 1999 |
| |
| Water solubility, mg/l : |
| 70000 |
25°C |
| 58000 |
MITI 1992 |
| |
| Melting point, °C : |
| 172 |
|
| 169 |
169 - 171 °C, IUCLID 1996 |
| 171 |
|
| |
| Boiling point, °C : |
| 285 |
285 - 287 °C, IUCLID 1996 |
| 287 |
|
| |
| Flashing point, °C : |
| 165 |
closed cup, IUCLID 1996 |
| |
| pKa : |
| 10.85 |
at 25 °C, HSDB 1999 |
| |
| Log octanol/water coefficient, log Pow : |
| 0.5 |
IUCLID 1996 |
| 0.59 |
HSDB 1999 |
| |
| Volatilization : |
The Henry's Law constant was estimated from the vapor pressure
(1.9x10-5 mmHg at 25 °C) and the water solubility (72 g/l 25°C)
and it is 3.84x10-11 atm m3/mol.
The vapor pressure and the
Henry's Law constant indicate that significant volatilization
from dry and moist soil is not expected (IUCLID 1996).
Hydroquinone is not expected to volatilize from water based on
this estimated value of the Henry's Law constant (HSDB 1999).
|
| |
| Adsorption/desorption : |
An estimated Koc is 9 to 50 (IUCLID 1996).
|
| |
| Mobility : |
The Koc-values indicate that hydroquinone has a very low
capability to adsorb and will display high to very high
mobility in soil (IUCLID 1996).
|
| |
| Other physicochemical properties : |
Very soluble in carbon tetrachloride.
|
| |
| Photochemical degradation in air : |
Photooxidation half-life in air:
26.1hr - 2.6hr, scientific judgement based upon an estimated
rate constant for vapor phase reaction with hydroxyl radicals
in air (Howard 1991).
If hydroquinone is released to the atmosphere, it is expected
to undergo direct photochemical degradation.
Direct photolysis:
57 % after 17 hr (measured) at 15 °C, light spect. 290 nm
The mineralization is calculated as the percentage CO2 to the
theorical possible carbon dioxide (IUCLID 1996).
An estimated rate constant for the gas-phase reaction of
hydroquinone with photochemically produced hydroxyl radicals of
2.3x10-11 cm3/molc-sec translates to a half-life of 16.8 hr
using an average atmospheric hydroxyl radical concn of 5x10+5
molc/cm3 (HSDB 1999).
|
| |
| Photochemical degradation in water : |
Photooxidation half-life in water:
19.3hr - 23min, scientific judgement based upon measured rate
data for alkylperoxyl radicals in aqueous solution (Howard
1991).
|
| |
| Half-life in air, days : |
| 1.09 |
26.1hr - 2.6hr. |
| 0.11 |
scientific judgement based upon estimated photooxidation halr-life in air. |
| |
Howard 1991 |
| |
| Half-life in soil, days : |
| 7 |
7d - 1d, |
| 1 |
scientific judgement based upon estimated unacclimated aqueous aerobic biodegradation half-life. |
| |
Howard 1991 |
| |
| Half-life in water, days : |
| 0.8 |
19.3hr - 0.39hr, |
| 0.02 |
in surface water: based upon photooxidation half-life in water. |
| 14 |
14d - 2d, |
| 2 |
in ground water: scientific judgement based upon estimated unacclimated aqueous aerobic biodegradation half-life. |
| |
Howard 1991 |
| |
| Aerobic degradation in water : |
Aerobic half-life:
7d - 1d, scientific judgement based upon aqueous screening test
data (Howard 1991).
Biodegradation:
concentration: 50 mg/l related to DOC
degradation: 86 % after 14 d
readily biodegradable (OECD 301 C)
(IUCLID 1996).
Biodegradation:
concentration: 2 mg/l related to DOC
degradation: 81 % after 30 d
readily biodegradable (OECD 301 D)
(IUCLID 1996).
Biodegradation:
concentration: 400 mg/l related to DOC
degradation: 66 % after 14 d
inherent biodegradability (OECD 302 B)
(IUCLID 1996).
|
| |
| Anaerobic degradation in water : |
Anaerobic half-life:
28d - 4d, scientific judgement based upon estimated
unacclimated aqueous aerobic biodegradation half-life (Howard
1991).
|
| |
| Total degradation in water : |
Biodegradation:
70% by BOD
period: 14d
substance: 100 mg/l
sludge: 30 mg/l
(MITI 1992)
|
| |
| Ready biodegradability : |
Confirmed to be biodegradable (Anon. 1987). |
| |
| Bioconcentration factor, fishes : |
| 40 |
3d, at 23 °C, Leuciscus idus melanotus, |
| |
conc. 0.05 mg/l, IUCLID 1996 |
| |
| Other information of bioaccumulation : |
Bioconcentration factor (algae):
40 - 65, 1d, Chlorella fusca, conc. 0.05 mg/l
(IUCLID 1996). |
| |
| LD50 values to mammals in oral exposure, mg/kg : |
| 320 |
orl-rat, Lewis & Sweet 1984 |
| 70 |
orl-cat, - " - |
| |
| LD50 values to mammals in non-oral exposure , mg/kg : |
| 5970 |
skn-mam, Lewis & Sweet 1984 |
| |
| LD50 values to birds in oral exposure, mg/kg : |
| 300 |
orl-pgn, Lewis & Sweet 1984 |
| |
| Effects on microorganisms : |
Toxicity threshold (cell multiplication inhibition test):
bacteria (Pseudomonas putida): 58 mg/l
(Bringmann & Kühn 1980a)
|
| |
| EC50 values to algae, mg/l : |
| 13.5 |
5 d, Scenedesmus subspicatus |
| 0.335 |
3 d, Selenastrum capricornutum |
| |
IUCLID 1996 |
| |
| LOEC values to algae, mg/l : |
| 0.93 |
Scenedesmus quadricauda, Bringmann & |
| |
Kühn 1980a |
| |
-- |
| 1 |
7 d, Selenastrum capricornutum, IUCLID 1996 |
| |
| NOEC values to algae, mg/l : |
| 0.4 |
7 d, Selenastrum capricornutum, IUCLID 1996 |
| |
| LC50 values to crustaceans, mg/l : |
| 0.05 |
48 hr, Daphnia magna, Könemann 1979 |
| |
| EC50 values to crustaceans, mg/l : |
| 0.29 |
48 hr, Daphnia magna |
| 0.16 |
48 hr, Daphnia pulicaria |
| 0.12 |
24 hr, Daphnia magna |
| |
IUCLID 1996 |
| |
-- |
| 0.13 |
48 hr, Daphnia magna |
| 0.16 |
48 hr, Daphnia pulicaria |
| |
IUCLID 1996 |
| |
| LC50 values to fishes, mg/l : |
| 0.097 |
96 hr, Salmo gairdneri, DeGraeve et al. |
| |
1980 |
| 0.044 |
96 hr, Pimephales promelas, - " - |
| |
-- |
| 0.17 |
96hr, Branchydanio rerio |
| 0.16 |
48hr, Leuciscus idus, Wellens 1982 |
| |
-- |
| 0.044 |
96 hr, Pimephales promelas |
| 0.639 |
96 hr, Salmo gairdneri, OECD 203 |
| 0.097 |
96 hr, Salmo gairdneri |
| 0.17 |
96 hr, Brachydanio rerio |
| |
IUCLID 1996 |
| |
-- |
| 0.044 |
0.044 - 0.097 mg/l, 96 hr, Oncorhynchus mykiss |
| 0.097 |
AQUIRE 1999 |
| |
| Other information of water organisms : |
Daphnia pulex: 0.001 mol/l, srv, 0.07 days (Stom et al. 1986).
Toxicity threshold (cell multiplication inhibition test):
green algae (Scenedesmus quadricauda): 0.93 mg/l
protozoa (Entosiphon sulcatum): 11 mg/l
(Bringmann & Kühn 1980a)
|
References |
| 1848 | Anon. 1987a.
The list of the existing chemical substances tested
on biodegradability by microorganisms or bioaccumulation in
fish body by Chemicals Inspection & Testing Institute.
Ministry
of International Trade and Industry, MITI.
Japan. |
| 3107 | AQUIRE 1993 -.
Aquatic Toxity Information Retrieval Database.
U.S.Environmental Protection Agency, Office of Pesticides and
Toxic Substances, Washington, D.C.
|
| 188 | Bringmann, G. & Kühn, R. 1980a.
Comparison of the toxicity
thresholds of water pollutants to bacteria, algae and
protozoa in the cell multiplication inhibition test.
Water
Res. 14: 231 - 241. |
| 331 | DeGraeve, G.M. et al. 1980.
Toxicity of underground coal
gasification condenser water and selected constituents to
aquatic biota.
Arch.
Environ.
Contam.
Toxicol. 9: 543. |
| 330 | DeGraeve, G.M., Geiger, D.L., Meyer, J.S. & Bergman, H.L.
1980.
Acute and embryo-larval toxicity of phenolic compounds to
aquatic biota.
Arch.
Environ.
Contam.
Toxicol. 9: 557 - 568. |
| 3120 | Howard, P.H., Boethling, R.S., Jarvis, W.F., Meylan, W.M. &
Michalenko, E.M., Handbook of Environmental Degradation Rates,
1991.
Lewis Publicers, Inc., Chelsea, Michigan, U.S.A.,
pp. 725.
|
| 3114 | HSDB Database 1992 -.
Hazardous Substances Data Bank.
US.
National Library of Medicine.
TOMES Plus CD-ROM.
|
| 3253 | IUCLID 1995 -.
International Uniform Chemical Information
Database.
European Commission.
European Chemicals Bureau.
Existing Chemicals.
Ispra, Italy.
|
| 761 | Könemann, W.H. 1979.
Quantitative structure-activity
relationships for kinetics and toxicity of aquatic pollutants and
their mixtures in fish.
Univ.
Utrecht, Netherlands. |
| 1589 | Lewis, R.J. & Sweet, D.V. 1984.
Registry of toxic effects of
chemical substances.
National Institute for Occupational Safety
and Health.
No. 83-107-4. |
| 3105 | MITI 1992.
Biodegradation and bioaccumulation data of existing
chemicals based on the CSCL Japan.
Compild under the Safety
Division Basic Industries Bureau Ministry of International
Trade & Industry, Japan.
Edited by Chemicals Inspection &
Testing Institute, Japan.
|
| 1927 | Stom D.J. et al. 1986.
Effect of individual phenolic compounds
and of their mictures on luminous bacteria.
Part 3.
Combined
action of phenolic compounds on aquatic organisms.
Acta
Hydrochim.
Hydrobiol. 14: 539. |
| 1531 | Wellens, H. 1982.
Comparison of the sensitivity of
Branchydanio rerio and Leucistus idus by testing the fish
toxicity of chemicals and wastewaters.
Z.
Wasser Abwasser
Forsch.
(Ger.) 15: 49. |
