Mercury, organic derivatives

Mercury is most accurately determined by the cold vapor atomic absorption spectroscopic method. The instrument is set at the wavelength 253.7 nm. The metal, its salts and organic derivatives in aqueous solution can be measured by this method. The solution or the solid compounds are digested with nitric acid to convert into water-soluble mercury(ll) nitrate, followed by treatment with potassium permanganate and potassium persulfate under careful heating. The excess oxidants in the solution are reduced with NaCl-hydroxylamine sulfate. The solution is treated with stannous chloride and aerated. The cold Hg vapor volatdizes into the absorption cell where absorbance is measured. 

Metals more electronegative than magnesium, like beryllium, zinc, cadmium and mercury, form useful reagents for specific purposes, but the metals themselves are not sufficiently active to form organic derivatives under normal laboratory conditions and are unwanted in the environment since they are toxic. Aluminum compounds are useful for industrial purposes, but their use in the laboratory is insignificant in comparison with Grignard reagents. 

Organic derivatives of mercury are more hazardous than the simple inorganic salts because they are lipid soluble and hence bioconcentrate. These species are able to cross the blood-brain barrier, thereby causing the neurological symptoms associated with mercury intoxication. 

A method based on a similar principle was proposed for the determination of selenium in tellurium [155], A metal sample was dissolved in dilute (1 1) aqua regia to which an acidified solution of 4-phenyl-o-phenylenediamine was added. The resulting 5-nitro-piazelenol was determined chromatographicaUy on a column of SE-30 at 200°C with detection of the organic derivative of selenium by an electron-capture detector. Analogous methods were used for the analysis of selenium and mercury in pure sulphuric acid [156] and sea water [157]. 

Arsenic has a considerable ability to accumulate in river sediments and aquatic organism. Similarly to mercury, organic methyl derivatives can be formed by the biological activity. 

The growth of the dyestuff industry in America made it desirable to broaden to some extent the treatment of the aromatic compounds and to include brief descriptions of the more important intermediates and of the sulphur and vat dyes. The increasing use of the organic derivatives of mercury and of arsenic in combating disease made it necessary to introduce an elementary consideration of the general reactions underlying the preparation of such compounds. 

Runoff as well as rainout carries soluble and adsorbed mercury into freshwater bodies and oceans. The very low levels of mercury available from the small solubility of humates and other mercury complexes are the source of mercury for land and water plants. Aquatic organisms derive a part of the mercury by ingestion of water plants, such as phytoplankton. Another source of mercury for aquatic organisms is zooplankton, which derives its mercury by ingestion of clay particles. These clay particles are agglomerated and then sedimented as part of the plankton excrement. 

I. P. Beletskaya, J. Organomet. Chem., 1983, 250, 551-564. The Cross-Coupling Reactions of Organic Halides with Organic Derivatives of Tin, Mercury, and Copper Catalyzed by Palladium. 

It is particularly suitable for elements that are volatile, such as mercury, or form volatile hydrides, such as arsenic or bismuth, or for elements forming stable volatile organic derivatives. 

Furmanova, N. G., Kuzmina, L. G., Struchkov, Yu. T., Structural Evidence of Coordination Interactions in Organic Derivatives of Mercury, Tin, and Lead, J. Organometal. Chem. Libr. 9 [1980] 153/87. 

Between 1965 and 1974, 520 patients at one location in Nigata were treated for this disease. All of these cases came from the mercury released from the plant. The cases were unexpected because the elemental form of mercury does not cause these effects. However, once the mercury was released into the water, the aquatic plant life and microbes in the sediment of the bay converted the mercury, as part of their regular physiological functions, to an organic form known as methylmer-cury. The methylmercury was then taken up by fish and shellfish that ate the plants or animals that lived in the sediments. Local fishermen then ate the fish and shellfish, and it was these people that reported the toxic effects. This organic derivative of mercury can enter the nervous system while the original, elemental form cannot. 

The first metal-ate complex, sodium triethylzincate, " was obtained by John Wanklyn who treated diethylzinc with elemental sodium in an attempt to produce ethylsodium. A systematic and reliable approach to ate complexes is the addition of a more polar organometallic reagent (eg., an organolithium) to a less polar organic derivative of an alkali-earth metal, transition element, or metalloid. In this way, a wealth of ate complexes of berrylium, magnesium, zinc, copper, boron, aluminum, silicon, tin, and mercury as well as of nonmetals like phosphorus, sulfur, selenium, tellurium, and even iodine " have been obtained. 

Mercury. The fkst successful use of mercury as a fungicide occurred in 1913 (8). The fkst seed treatment compound developed was chloro(2-hydroxyphenyl)mercury [90-03-9] (1). Subsequentiy, a number of organic mercury derivatives having general formula RHgX have been used. 

The high temperatures in the MHD combustion system mean that no complex organic compounds should be present in the combustion products. Gas chromatograph/mass spectrometer analysis of radiant furnace slag and ESP/baghouse composite, down to the part per biUion level, confirms this behef (53). With respect to inorganic priority pollutants, except for mercury, concentrations in MHD-derived fly-ash are expected to be lower than from conventional coal-fired plants. More complete discussion of this topic can be found in References 53 and 63. 

The control of mercury in the effluent derived from the manufacturing processes used in the preparation of inorganic and organic mercurials is mandated bylaw in the United States. The concentrations and the total amounts vary with the industry and the location, but generally it is requited that the... 

MIcrobiocldes. There are several microbiocides available commercially that can perform an effective function in controlling microbial activity. Some of these chemicals are inorganic, such as chlorine, sodium hypochlorite, calcium hypochlorite, hydrogen peroxide, chromates and compounds of mercury and silver. However, the organic chemicals find the highest use as microbiocides. Some examples of these organic compounds are peracetic acid, paraformaldehyde, polychlorophenols and quaternary ammonium derivatives, to name a few [208]. 

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