NITRAPYRIN

CASRN: 1929-82-4; molecular formula: C6H3Cl4N; FW: 230.90; RTECS: US7525000; Merck Index: 12, 6666 Physical state, color, and odor: Colorless to white crystalline solid with a mild, sweet odor Melting point (°C): 62-63 (quoted, Verschueren, 1983) Density (g/cm3): 1.744 using method of Lyman et al. (1982) Entropy of fusion (cal/mol⋅K): 14.39 (Tan et al., 1989) Heat of fusion (kcal/mol): 4.85 (Tan et al., 1989) Henry’s law constant (x 10-3 atm⋅m3/mol): 2.13 (approximate - calculated from water solubility and vapor pressure) Soil organic carbon/water partition coefficient, log Koc: 2.64 (Commerce soil), 2.68 (Tracy soil), 2.66 (Tracy soil) (McCall et al., 1981) 2.62 (Kenaga and Goring, 1980) 2.24 (Cottenham sandy loam, Briggs, 1981) Octanol/water partition coefficient, log Kow: 3.41 (Kenaga and Goring, 1980) 3.02 at 20 °C (TLC retention time correlation, Briggs, 1981) Solubility in organics: At 20 °C: acetone (1.98 kg/kg), methylene chloride (1.85 kg/kg); 22 °C: anhydrous ammonia (540 g/kg), ethanol (300 g/kg); 26 °C: xylenes (1.04 kg/kg) (Worthing and Hance, 1991) Solubility in water: 40 mg/L at 22 °C (Worthing and Hance, 1991) Vapor pressure (mmHg): 2.8 x 10-3 at 20 °C (quoted, Verschueren, 1983) Environmental fate: Biological. 6-Chloropicolinic acid and carbon dioxide were reported as biodegradation products (quoted, Verschueren, 1983). Soil. Hydrolyzes in soil to 6-chloropyridine-2-carboxylic acid which is readily absorbed by

Photolytic. Photolysis of nitrapyrin in water yielded 6-chloropicolinic acid, 6-hydroxypicolinic acid, and an unidentified polar material (quoted, Verschueren, 1983). Chemical/Physical. Emits toxic nitrogen oxides and chloride fumes when heated to decomposition (Lewis, 1990). Exposure limits (mg/m3): NIOSH REL: TWA 10, STEL 20, IDLH 250; OSHA PEL: TWA 15; ACGIH TLV: TWA 10, STEL, 20 (adopted). Toxicity: LC50 for channel catfish 5.8 mg/L (Worthing and Hance, 1991). LC50 (8-d) for mallard ducks 1,466 mg/kg diet, Japanese quail 820 mg/kg diet (Worthing and Hance, 1991). Acute oral LD50 for chickens 235 mg/kg, mice 710 mg/kg, rats 940 mg/kg, rabbits 500 mg/kg (quoted, RTECS, 1985). Acute percutaneous LD50 (24-h) for rabbits 2,830 mg/kg (Worthing and Hance, 1991). In 94-d feeding trials using rats and dogs, the NOELs were 300 and 600 mg/kg diet, respectively (Worthing and Hance, 1991). Uses: Not commercially produced in the United States. Nitrification inhibitor in ammonium fertilizers.