ABSTRACT

CASRN: 95-53-4; DOT: 1708; DOT label: Poison; molecular formula: C7H9N; FW: 107.16; RTECS: XU2975000; Merck Index: 12, 9674 Physical state, color, and odor: Colorless to pale yellow liquid with an aromatic, aniline-like odor. Becomes reddish-brown on exposure to air and light. Odor threshold concentration is 250 ppb (quoted, Amoore and Hautala, 1983). Melting point (°C): -14.7 (Weast, 1986) Boiling point (°C): 200.2 (Weast, 1986) Density (g/cm3 at 20 °C): 0.9984 (Weast, 1986) 1.004 (quoted, Verschueren, 1983) Diffusivity in water (x 10-5 cm2/sec): 0.85 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: 4.43 at 25 °C (Hall, 1930) 4.5 at 25 °C (Golumbic and Goldbach, 1951) 5.17 (Johnson and Westall, 1990) Flash point (°C): 86 (NIOSH, 1997) Entropy of fusion (cal/mol⋅K): 7.6 (Meva’a and Lichanot, 1990) Heat of fusion (kcal/mol): 1.936 (Meva’a and Lichanot, 1990) Henry’s law constant (x 10-6 atm⋅m3/mol): 1.98 at 25 °C (thermodynamic method-GC/UV spectrophotometry, Altschuh et al., 1999) Ionization potential (eV): 7.47 (Lias, 1998)

oc 2.61 (calculated, Mercer et al., 1990) Octanol/water partition coefficient, log Kow: 1.29 (quoted, Leo et al., 1971) 1.32 (HPLC, Carlson et al., 1975) 1.40 (shake flask, Johnson and Westall, 1990) Solubility in organics: Soluble in alcohol and ether (Weast, 1986). Solubility in water (g/L at 25 °C): 15 (quoted, Verschueren, 1983) 16.33 (shake flask-GC, Chiou et al., 1982) Vapor density: 4.38 g/L at 25 °C, 3.70 (air = 1) Vapor pressure (mmHg): 0.1 at 20 °C, 0.3 at 30 °C (quoted, Verschueren, 1983) 0.32 at 25 °C (Banerjee et al., 1990) Environmental fate: Biological. Heukelekian and Rand (1955) reported a 5-d BOD value of 1.40 g/g which is 55.1% of the ThOD value of 2.54 g/g. Chemical/Physical. Kanno et al. (1982) studied the aqueous reaction of o-toluidine and other substituted aromatic hydrocarbons (aniline, toluidine, 1-and 2-naphthylamine, phenol, cresol, pyrocatechol, resorcinol, hydroquinone, and 1-naphthol) with hypochlorous acid in the presence of ammonium ion. They reported that the aromatic ring was not chlorinated as expected but was cleaved by chloramine forming cyanogen chloride. As the pH was lowered, the amount of cyanogen chloride formed increased (Kanno et al., 1982). o-Toluidine will not hydrolyze because it does not contain a hydrolyzable functional group (Kollig, 1993). Exposure limits: Potential occupational carcinogen. NIOSH REL: IDLH 50 ppm; OSHA PEL: TWA 5 ppm (22 mg/m3); ACGIH TLV: TWA 2 ppm (adopted). Symptoms of exposure: May cause methemoglobinemia, anemia, and reticulocytosis. Contact with skin may cause irritation and dermatitis (Patnaik, 1992). Toxicity: EC50 (48-h) and EC50 (24-h) values for Spirostomum ambiguum were 3,708 mg/L (NałeczJawecki and Sawicki, 1999). LC50 (48-h) and LC50 (24-h) values for Spirostomum ambiguum were 5,412 mg/L (NałeczJawecki and Sawicki, 1999). Acute oral LD50 in mice 520 mg/kg, rats 670 mg/kg, rabbits 840 mg/kg (quoted, RTECS, 1985). Source: As o+p-toluidine, detected in distilled water-soluble fractions of 87 octane gasoline and Gasohol at concentrations of 0.80 and 0.19 mg/L, respectively (Potter, 1996). o-Toluidine was detected in 77% of 65 gasoline (regular and premium) samples (62 from Switzerland, 3 from Boston, MA). At 25 °C, concentrations ranged from 13 to 18,000 µg/L in gasoline and 10 to 1,400

in water-soluble fractions (Schmidt et al., 2002). Uses: Manufacture of dyes; vulcanization accelerator; organic synthesis.