The volatility of organo‐mercury compounds

Abstract

The saturated vapour concentrations at 35" of 21 organo-mercury compounds have been determined by static and dynamic methods and the corresponding partial pressures derived. For 14 of these compounds, together with mercury and mercuric chloride, values at 25' and 45' have also been determined and the constants in the linear pressure-temperature relation calculated. Some correlation between chemical constitution and vapour pressure has been noted. IntroductionDespite their inherent toxicity, the good fungicidal and bactericidal properties of organomercury compounds have encouraged their widespread use in agriculture. To assess the inhalation hazard arising from the use of eradicant sprays and the dressing of stored seed, the clinical data on intrinsic toxicity must be supplemented with knowledge of the approximate volatility of each compound. Since the published vapour pressure data in this field are scanty, it was decided to determine experimentally the saturated vapour concentrations of as many of the organo-mercurials currently in use as could be obtained.Whereas grain is usually stored in a cool atmosphere and the bulk of fruit spraying in this country is over orchard crops, some fungicidal aerosols are employed in greenhouses, notably on tomatoes. Taking into consideration the English climate and the ventilation procedure

Distribution, speciation, and budget of atmospheric mercury

“…The fate of MC in the troposphere is unknown. Based on solubility data and the vapor pressure of MC (Phillips et al, 1959;Kaiser and T61g, 1980) it is likely that MC will be effectively removed by aerosol attachment and by rain and washout (Junge, 1977).…”

Mercury in soil derived from igneous rock in Northern Kyushu, Japan

“…This suggests that HgS is not a major form of the element. Some liberation of Hg occurred at relatively low heat treatment temperatures (50-100°C) and may be attributed to the presence of Hgo and/or highly volatile organo-mercury compounds (37). Soils are known to contain, in some cases, considerable quantities of Hg as the elemental vapor on the organic as well as inorganic soil fractions (22,43).…”

Solvation parameters for mercury and mercury(ii) compounds: calculation of properties of environmental interest

“…Log K w was allowed to vary, the obtained value for it being log K w ¼ 6.36. From the aqueous solubility, 44 log S w ¼ À4.22 and the saturated vapor concentration at 298 K (obtained from the given equation for the temperature variation of vapor pressure) 45 log C g ¼ À10.19 a value for log K w of 5.97 is found. Our 'floating' value of 6.36 is in reasonable agreement.…”

“…Although this has been used as a fungicide under the name 'Aretan', the only physicochemical data we have been able to find are the vapor pressure 45 that corresponds to log C g ¼ À7.75 at 298 K, and the aqueous solubility 53 that yields log S w ¼ À0.77; from these, log K w ¼ 6.98. The descriptors given in Table 3 are approximate only, in that they simply reproduce the log K w value.…”