Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
HYDROFLUOROCARBON-23 28 Common name: HFC-23 Chemical name: Trifluromethane Synonyms: Freon 23, Genetron 23, fluoroform, HC-23, fluoryl, Arcton 1, carbon trifluoride, halocarbon 23, methyl trifluoride, R 23, FE-13 CAS number: 75-46-7 Structural formula: HCF3 Description: Colorless gas Molecular weight: 70.01 Boiling point: -82.03°C at 760 mm Hg Melting point: -155.2°C Density and specific gravity: 0.670 g/mL at 25°C Vapor pressure: 686 psig at 25°C (77°F) Vapor density: 2.4 (Air = 1.0) Flash point and flammability: Nonflammable Solubility: 0.10 wt% in water Autoignition: 765°C (1409°F) Octanol and water partition coefficient: Kow = 0.64 Conversion factors: 1 mg/m3= 0.35; 1 ppm = 2.86 mg/m3> TOXICOKINETICS Ewing et al. (1990) studied the use of HFC-23 in nuclear magnetic resonance spectroscopy as a gaseous indicator of cerebral blood flow in cats. HFC-23 at a concentration of 600,000 ppm was rapidly absorbed from the lungs and the arterial blood concentration reached a plateau within 3 or 4 min after initiation of the exposure. Likewise, HFC-23 was rapidly eliminated from the blood upon termination of the exposure. It was also rapidly taken up by the brain, with the brain uptake lagging the arterial blood uptake by about 2 min. Similar findings were demonstrated with 670,000 ppm by Detre et al. (1990) in the rat.