VAPOR DENSITY OF DIELDRIN

Vapor density associated with solid-phasedieldrin (HEOD, 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-1,4-endo-exo-5,8-dimethanonaphthalene) and dieldrin-soil mixtures, measured by a gas-saturation technique, was three to 12 times greater than predicted from published vapor pressure values. The measured vapordensities at 20, 30, and 40° C. were 54, 202, and 676 ng. of HEOD per liter, respectively. The vapor density of HEOD in three dry dieldrin materials was the same asthat of HEOD plus water. The vapor density of HEOD in soil at 100 p.p.m. was the same as that of HEOD without soil, but at 10 p.p.m. the vapor density in soil was reduced approximately 80%. The heat of vaporization of HEOD with or without soil was 23.6 kcal. per mole. The data indicate that the so-called “codistillation” phenomenon is not due to an increased vapor density in the presence of evaporating water and that loss of water isnot required to attain maximum vapor density of HEOD, either in soil or over HEOD-water mixtures. © 1969, American Chemical Society. All rights reserved.