| Chemical |
alfa-Methylstyrene |
| CAS-number : |
98-83-9 |
| |
| Synonyms : |
| (1-methylethenyl)benzene |
| 1-Methyl-1-phenylethene |
| 1-methyl-1-phenylethylene |
| 2-phenyl-1-propene |
| alpha-methyl styrene |
| beta-phenylpropylene |
| isopropenylbenzene |
| |
| Sumformula of the chemical : |
| C9H10 |
| EINECS-number : |
| 2027050 |
| |
| State and appearance : |
Alfa-methylstyrene is a colorless liquid.
|
| |
| Odor : |
Characteristic sweet, aromatic odor.
|
Quality: sweet, aromatic
Hedonic tone: pleasant
Threshold odour concentration
absolute: 0.052 ppm
50 % recognition: 0.156 ppm
100 % recognation: 0.156 ppm
Odour index 100 % recognition: 16 020
(Hellman & Small 1974). |
| |
| Molecular weight : |
118.18 |
| |
| Spesicif gravity (water=1) : |
| 0.91 |
at 20 °C, IUCLID 1996 |
| |
| Vapor pressure, mmHg : |
| 2.25 |
at 20 °C, IUCLID 1996 |
| 1.9 |
at 20 °C, HAZARDTEXT 1998 |
| |
| Water solubility, mg/l : |
| 1000 |
<1 g/l, at 20 °C, IUCLID 1996 |
| 560 |
at 25 °C, HAZARDTEXT 1998 |
| |
| Melting point, °C : |
| -23.2 |
IUCLID 1996 |
| |
| Boiling point, °C : |
| 161 |
161-162, MITI 1992 |
| 165 |
at 1013 hPa, IUCLID 1996 |
| |
| Flashing point, °C : |
| 40 |
ca. 40 °C, closed cup, IUCLID 1996 |
| |
| Log octanol/water coefficient, log Pow : |
| 3.265 |
IUCLID 1996 |
| 3.35 |
HAZARDTEXT 1998 |
| 3.44 |
LOGKOW 1994 |
| 3.27 |
IUCLID 2000 |
| |
| Henry's law constant, Pa x m3/mol : |
| 53 |
at 20 °C, HAZARDTEXT 1998 |
| |
| Volatilization : |
Volatilization from water may be important.
The Henry's Law
Constant is estimated to be 5.28 x 10-4 atm m3/mole at 25 °C
(HAZARDTEXT 1998).
Based on estimated Henry's Law constant, the volatilization
half-life of alpha-methylstyrene from a model river is
estimated to be 5 hours and from a model pond (considering the
effect of adsorption) is approx. 9 days (HAZARDTEXT 1998).
|
| |
| Mobility : |
Based on a water solubility of 560 ppm at 25 °C and a log Kow
3.35, the Koc for alpha-methylstyrene can be calculated using
various regression equations to range from 135 to 1585, which
indicate an uncertainty in the mobility (HSDB 1998).
alpha-Methylstyrene may adsorb to carbon and partition from the
water column to organic matter in sediments and suspended
solids because of the estimated Koc ranging from the low to
high mobility class (HAZARDTEXT 1998).
The mobility of alpha-methylstyrene in soils is uncertain due
to the calculated Koc range of 135 to 1585 (HAZARDTEXT 1998).
|
| |
| Photochemical degradation in air : |
Atmospheric alpha-methylstyrene is likely to exist entirely in
the vapor phase due to its vapor pressure of 1.9 mmHg at 20 °C.
Reaction with photochemically produced hydoxyl radicals and
ozone are exppected to be more important fate processes than
direct photolysis.
The atmospheric transformation of
alpha-methylstyrene may be affected by reactions with nitrate
radicals during the night, especially in urban environments
(HAZARDTEXT 1998).
alpha-Methylstyrene may undergo direct photolysis in sunlit
waters and surface soils due to its weak adsorption of UV light
at wavelenght greater than 290 nm (HAZARDTEXT 1998).
The half-life of the reaction of alpha-methylstyrene in the
vapor phase with photochemically-produced hydroxyl radicals is
approx. 7.5 hours at an atmospheric hydroxyl radical
concentration of 5 x 10+5 molecules/cm3, using a rate constant
of 5.2 x 10-11cm3/molecule-sec at 25 °C (HAZARDTEXT 1998).
The rate constant for the vapor-phase reaction of
alpha-methylstyrene with ozone has been estimated to be
1.365x10-16 cm3/molecule-sec at 25 °C which corresponds to an
atmospheric half-life of about 2 hours at an atmospheric concn
of 7x10+11 molecules/cm3 (HSDB 1998).
|
| |
| Photochemical degradation in soil : |
alpha-Methyl styrene may undergo direct photolysis in sunlit
surface soils doe to its weak absorption of UV light at
wawelenght greater than 290 nm (HAZARDTEXT 1998).
|
| |
| Photochemical degradation in water : |
alpha-Methyl styrene may undergo direct photolysis in sunlit
waters doe to its weak absorption of UV light at wawelenght
greater than 290 nm (HAZARDTEXT 1998).
|
| |
| Total degradation in water : |
Biodegradation:
0% by BOD
period: 14d
substance: 100 mg/l
sludge: 30 mg/l
(MITI 1992)
|
| |
| Bioconcentration factor, fishes : |
| 15 |
15 - 140, 8w, Cyprinus carpio, conc 0.3 mg/l, |
| 140 |
|
| 12 |
12 - 113, 8w, Cyprinus carpio, conc 0.03 mg/l, |
| 113 |
MITI 1992 |
| |
| Other information of bioaccumulation : |
In goldfish the log BCF is 1.47, indicating that
bioconcentration of alpha-methyl styrene in aquatic organisms
is unlikely (HAZARDTEXT 2000).
|
| |
| LC50 values to crustaceans, mg/l : |
| 4.2 |
48 hr, Chaetogammarus marinus, IUCLID 1996 |
| |
| LOEC values to crustaceans, mg/l : |
| 1.8 |
72 hr, Chaetogammarus marinus, IUCLID 1996 |
| |
| LC50 values to fishes, mg/l : |
| 6.8 |
48 hr, Oryzias latipes, MITI 1992 |
| 10 |
96 hr, Pimephales promelas, HAZARDTEXT 1998 |
| |
| LOEC values to fishes, mg/l : |
| 28 |
48 hr, Leuciscus idus, IUCLID 1996 |
| |
| NOEC values to fishes, mg/l : |
| 5 |
24 hr, Salmo gairdneri, IUCLID 1996 |
| |
| Other information of water organisms : |
LC10, 283 mg/l, 18 hr, Pseudomonas putida, IUCLID 1996.
|
References |
| 3338 | HAZARDTEXT Database. 1998 -.
Hazardous Materials Emergency
Response Information.
American Association of Railroads,
National Fire Protection Association, Department of
Transportation, Environmental Protection Agency and
Occupational Safely & Health Administration.
TOMES Plus CD-ROM.
|
| 1673 | Hellman, T.M. & Small, F.H. 1974.
Characterization of the odour
properties of 101 petrochemicals using sensory methods.
J.
Air
Pollut.
Control Assoc. 24: 979 - 982. |
| 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.
|
| 3182 | LOG KOW 1994.
Octanol-water partition coefficient program.
Syracure Research Corporation.
Chemical Hazard Assessment
Division.
Environmental Chemistry Center.
|
| 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.
|
