IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

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(e) Spectroscopy data: Infrared, ultraviolet, nuclear magnetic resonance and mass
spectral data have been reported (Weast & Astle, 1985; Sadtler Research
Laboratories, 1991; Lide, 1996).
(f ) Solubility: Insoluble in water; soluble in acetone, diethyl ether and ethanol
(Lide, 2001). Very soluble in benzene and petroleum ether (WHO, 1983)
(g) Volatility: Vapour pressure, 867 Pa at 25 ºC; relative vapour density (air = 1),
3.6 (WHO, 1983)
(h) Stability: Lower flammable limit, 1.1% by volume in air (Quincy, 1991); flash
point, 34 °C (National Institute for Occupational Safety and Health, 1983)
(i) Reactivity: Polymerizes easily at room temperature in the presence of oxygen
and oxidizes on exposure to light and air (WHO, 1983)
(j) Octanol-water partition coefficient (P): log P = 2.95 (Hansch et al., 1995)
(k) Conversion factor: mg/m 3 = 4.26 × ppm 1
1.1.4 Technical products and impurities
Styrene is available as a commercial product with the following specifications:
purity, 99.6–99.9% min.; ethylbenzene, 85 ppm max.; polymer content, 10 ppm max.;
para-tert- butylcatechol (polymerization inhibitor), 10–15 ppm or 45–55 ppm; aldehydes
(as benzaldehyde), 200 ppm max.; peroxides (as hydrogen peroxide), 0.0015 wt% or
100 ppm max.; benzene, 1 ppm max.; sulfur, 1 ppm typical; chlorides (as chlorine),
1 ppm typical (James & Castor, 1994; Chevron Phillips Chemical Co., 1996; Chen, 1997;
Chevron Phillips Chemical Co., 2001).
Typical analysis of a commercial styrene product reported the following components:
purity, 99.93%; benzene, < 1 ppm; toluene, < 1 ppm; ethylbenzene, 50 ppm;
α-methylstyrene, 150 ppm; meta- + para-xylene, 240 ppm; ortho-xylene, 80 ppm;
cumene, 70 ppm; n-propylbenzene, 40 ppm; meta- + para-ethyltoluene, 20 ppm; vinyltoluene,
10 ppm; phenylacetylene, 50 ppm; meta- + para-divinylbenzene, < 10 ppm;
ortho-divinylbenzene, < 5 ppm; polymer, 1 ppm; para-tert-butylcatechol, 12 ppm;
aldehydes (as benzaldehyde), 15 ppm; peroxides (as benzoyl peroxides), 5 ppm; chlorides
(as chlorine), < 1 ppm; and sulfur, < 1 ppm (Chevron Phillips Chemical Co., 2001).
1.1.5 Analysis
(a) Environmental monitoring
IARC MONOGRAPHS VOLUME 82
Styrene in workplace air can be determined by capillary column gas chromatography
(GC) with a flame ionization detector (FID). The sample is adsorbed on charcoal and
desorbed with carbon disulfide. This method (NIOSH Method 1501) has an estimated
limit of detection of 0.001–0.01 mg per sample (Eller, 1984).
1 Calculated from: mg/m3 = (relative molecular mass/24.45) × ppm, assuming normal temperature (25 °C)
and pressure (101.3 kPa)