Mercuric Chloride Oxide

Many mercury compounds are labile and easily decomposed by light, heat, and reducing agents. In the presence of organic compounds of weak reducing activity, such as amines (qv), aldehydes (qv), and ketones (qv), compounds of lower oxidation state and mercury metal are often formed. Only a few mercury compounds, eg, mercuric bromide/77< 5 7-/7, mercurous chloride, mercuric s A ide[1344-48-5] and mercurous iodide [15385-57-6] are volatile and capable of purification by sublimation. This innate lack of stabiUty in mercury compounds makes the recovery of mercury from various wastes that accumulate with the production of compounds of economic and commercial importance relatively easy (see Recycling). 

Mercuric Carbonate. Basic mercuric carbonate/7ti5 ti7-7< -7/, HgCO 3HgO, maybe prepared by the addition of sodium carbonate to a solution of mercuric chloride. The brown precipitate, which lacks usefulness, is generally not isolated rather, the slurry is refluxed, whereupon the carbonate decomposes to red mercuric oxide. 

The preparation of mercuric chloride is identical to the chamber method for mercurous chloride, except that an excess of chlorine is used to ensure complete reaction to the higher oxidation state. Very pure product results from this method. Excess chlorine is absorbed by sodium hydroxide in a tower. 

Mercuric chloride is widely used for the preparation of red and yellow mercuric oxide, ammoniated mercury/7(9/USP, mercuric iodide, and as an intermediate in organic synthesis. It has been used as a component of agricultural fungicides. It is used in conjunction with sodium chloride in photography (qv) and in batteries (qv), and has some medicinal uses as an antiseptic. 

Yellow mercuric oxide may be obtained by precipitation from solutions of practically any water-soluble mercuric salt through the addition of alkah. The most economical are mercuric chloride or nitrate. Although yellow HgO has some medicinal value in ointments and other such preparations, the primary use is as a raw material for other mercury compounds, eg, Millon s ha.se[12529-66-7], Hg2NOH, which is formed by the reaction of aqueous ammonia and yellow mercuric oxide. 

Galen, a physician whose views outUved him by about a thousand years, died about 200 AD. He beUeved that mercurials were toxic, and did not use any mercury compound therapeutically. However, as a result of Arabian influence, the therapeutic uses of mercury were slowly recognized by Western Europe. In the thirteenth century mercury ointments were prescribed for treating chronic diseases of the skin. Mercury and its compounds, such as mercurous chloride, mercuric oxide, mercuric chloride, and mercuric sulfide, were used widely from the fifteenth to the nineteenth centuries, and to some extent in the twentieth century. During the first half of the twentieth century, the primary therapeutic uses of mercury included bactericidal preparations, such as mercuric chloride, mercuric oxycyanide, and mercuric oxide and diuretics, such as aryl HgX (Novasural) and mercurated ahyl derivatives (14). 

Other ions, eg, ferrate, chloride, and formate, are determined by first removing the cyanide ion at ca pH 3.5 (methyl orange end point). Iron is titrated, using thioglycolic acid, and the optical density of the resulting pink solution is measured at 538 nm. Formate is oxidized by titration with mercuric chloride. The mercurous chloride produced is determined gravimetricaHy. Chloride ion is determined by a titration with 0.1 Ai silver nitrate. The end point is determined electrometricaHy. 

Atropine causes dilation of the pupil of the eye. A drop or two of an aqueous solution, containing 1 part in 130,000 parts of water, introduced into the eye of a cat is sufficient to produce this effect. When warmed with sulphuric acid and a small crystal of potassium dichromate, atropine develops a bitter almond odour. Evaporated to dryness on a water-bath with concentrated nitric acid, it gives a residue which becomes violet on adding a drop of sodium hydroxide solution in alcohol (Vitali s test). With a solution of mercuric chloride atropine gives a yellow to red precipitate of mercuric oxide. 

Merkuro-. mercurous, mercury (I), -azetat, n. mercurous acetate. mercury(I) acetate, -chlorld, n. mercurous chloride, mercury(I) choride. -chrom, n. (Pharm.) mercuro chrome, -jodid, n. n ercurous iodide, mer-cury(I) iodide. -nitrat, n. mercurous nitrate, mercury(I) nitrste. -oxyd, n. mercurous oxide, mercury(I) oxide, -salz, n. mercurous salt, mercury (I) salt, -sulfat, n. mercurouasulfate, mercury(I) sulfate, -sulfid, n. mercurous sulfide, mercury(I) sulfide, -verbindung, /. mercurous compound, mercury (I) compound. 

The more generally known mercuric oxide-mercuric chloride hydrolysis 2 may also be used, and in the present case it gives a yield of about 90%. The reductive desulfurization of Part E is also based on the work of Mukaiyama.12 It is clearly superior to Raney nickel desulfurization, which gives only 36-45% of 3-benzylindole. 

Oxidation of formic acid by mercuric chloride is the subject of several early kinetic studies. Dhar showed the reaction to be first-order in oxidant and substrate and to be subject to strong retardation by added chloride ions in agreement with earlier work. The reaction is also subject to retardation by added acid and presumably involves formate ion as the principal reactant. 

The oxidation of oxalic acid by mercuric chloride to give CO2 and mercurous chloride is a classic example of an induced reaction. This reaction is extremely slow unless small quantities of chromic acid and manganous ions are added, whereon facile reduction takes place Addition of permanganate or persulphate and some reducing agents is also effective and the oxidation proceeds readily under photo- or X-irradiation (Eder s reaction). The large quantum yield points to a chain mechanism , which could also function with an inducing oxidant, viz. 

Chemical precipitations which are not dependent on pH are used in various processes. Sometimes the reagent is reasonably set for a certain metal and this is the situation in the precipitation of silver as silver chloride. The only other insoluble common metal chlorides of significance are lead chloride, cuprous chloride, and mercurous chloride. This implies that precipitation of cuprous and mercurous chlorides generally may be avoided by ensuring that the metals occur in their higher oxidation states, cupric and mercuric states. The separation of silver in its chloride form is rarely employed for bulk precipitation, but is quite useful for removing relatively small amounts of the metal when it occurs in minor amounts. 

The general method, that has been widely used for the synthesis of perhydropyrrolo[1,2-6]isoxazoles, is based on a cycloaddition reaction of cyclic nitrones with dipolarophiles. The nitrone is easily available by oxidation of the corresponding hydroxylamine with mercuric chloride. The cycloaddition of nitrone to dipolarophiles is highly regioselective and stereoselective and have been often applied in the total synthesis of natural products <20010L1367, 2004BML3967, 2005JOC3157>. As one representative example of dipolar cycloaddition, reaction... 

ATP and magnesium were required for the activation of acetate. Acetylations were inhibited by mercuric chloride suggesting an SH group was involved in the reaction either on the enzyme or, like lipoic acid, as a cofactor. Experiments from Lipmann s laboratory then demonstrated that a relatively heat-stable coenzyme was needed—a coenzyme for acetylation—coenzyme A (1945). The thiol-dependence appeared to be associated with the coenzyme. There was also a strong correlation between active coenzyme preparations and the presence in them of pantothenic acid—a widely distributed molecule which was a growth factor for some microorganisms and which, by 1942-1943, had been shown to be required for the oxidation of pyruvate. 

Zinc enolate 4, prepared from acetylene ether pyridine i-oxide, mercuric chloride, and zinc, adds to aldehydes to form a-chloro-3-hydroxy esters 5 in good yields ( ). Subsequent treatment with base gives trans-epoxyesters, one of which 6 is converted to 2-amino-2-deoxy-D-ribose stereoselectively in good yields (O. 

Tolylmercuric chloride has been prepared from />-toluene-sulfinic acid and mercuric chloride,1 from /)-toluenesulfochloride and mercury diphenyl at 1200,2 by treating />-tolueneboric acid with mercuric chloride,3 by the direct mercuration of toluene with mercuric acetate,4 from -tolylmercuric nitrate and hydrochloric acid,5 from hydrochloric acid and / -tolylmercuric hydroxide formed by the oxidation of mercury di-/>-tolyl,6 and from mercury di-/>-tolyl by heating with mercuric chloride in alcohol.7... 

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