Mercurous perchlorate

Group 12 (IIB) Perchlorates. The zinc perchlorate [13637-61 -17, cadmium perchlorate [13760-37-7] mercury(I) perchlorate [13932-02-0] and mercury(II) perchlorate [7616-83-3] all exist. Cell potential measurements show that zinc and cadmium perchlorates are completely dissociated in concentrations up to 0.1 molar in aqueous solutions (47—49). Mercurous perchlorate forms a tetrahydrate that can be readily converted to the dihydrate on heating to above 36°C (50). 

Protonic initiation is also the end result of a large number of other initiating systems. Strong acids are generated in situ by a variety of different chemistries (6). These include initiation by carbenium ions, eg, trityl or diazonium salts (151) by an electric current in the presence of a quartenary ammonium salt (152) by halonium, triaryl sulfonium, and triaryl selenonium salts with uv irradiation (153—155) by mercuric perchlorate, nitrosyl hexafluorophosphate, or nitryl hexafluorophosphate (156) and by interaction of free radicals with certain metal salts (157). Reports of "new" initiating systems are often the result of such secondary reactions. Other reports suggest standard polymerization processes with perhaps novel anions. These latter include (Tf)4Al (158) heteropoly acids, eg, tungstophosphate anion (159,160) transition-metal-based systems, eg, Pt (161) or rare earths (162) and numerous systems based on tri flic acid (158,163—166). Coordination polymerization of THF may be in a different class (167). 

The reactivity of mercury salts is a fimction of both the solvent and the counterion in the mercury salt. Mercuric chloride, for example, is unreactive, and mercuric acetate is usually used. When higher reactivity is required, salts of electronegatively substituted carboxylic acids such as mercuric trifiuoroacetate can be used. Mercuric nitrate and mercuric perchlorate are also highly reactive. Soft anions reduce the reactivity of the Hg " son by coordination, which reduces the electrophilicity of the cation. The harder oxygen anions leave the mercuric ion in a more reactive state. Organomercury compounds have a number of valuable synthetic applications, and these will be discussed in Chapter 8 of Part B. 

Carbonoxy sulfide Mercuric perchlorate Vinyl chloride... 

On the other hand, this same amount of electricity will deposit exactly twice as much mercury, 2 x (6.03) = 12.1 grams, from a solution of mercurous perchlorate, Hg2(ClCh)2. If we restate Faraday s experimental finding in terms of the atomic theory, we see that the number of atoms of mercury deposited by a certain quantity of electricity is a constant or a simple multiple of this constant. Apparently this certain quantity of electricity can count atoms. A simple interpretation is that there are packages of electricity. During electrolysis, these packages are parcelled out, one to an atom, or two to an atom, or three. 

Mendeleev, Dimitri, 104,107 Mendelevium, oxidation number, 414 Mercuric perchlorate, 237 Mercurous perchlorate, 237 Mercury, oxidation numbers, 414 Mercury (planet), data on, 444 Metabolism, oxidative, 429 Metallic alloys, 309 bond, 303 elements. 303 radius, 380 substances, 81 Metals alkali, 94... 

An extensive investigation has been recently made of the kinetics of mercuration of benzene by mercuric acetate and mercuric perchlorate in acetic acid solvent, and the kinetic details are somewhat complicated439. 

The reaction was retarded by water, and this retardation was greater for mercuric perchlorate in the absence of added perchloric acid than for mercuric acetate in the presence of perchloric acid. 

Although mercuration by the two salts above appears at first sight to be fundamentally different, analysis of the above data shows that this is not the case439. Firstly, mercuric perchlorate in acetic acid is partially converted to mercuric acetate and perchloric acid thus, the first step is given by equilibrium (214)... 

The variation in the second-order rate coefficients with time and with change in initial concentration of mercuric salt can also be explained on the basis of equilibria (213) and (214). At low acidities, conversion of mercuric acetate to acetoxymercury perchlorate is incomplete, and, therefore, decreasing the concentration of the acetate increases the concentration of free perchloric acid which thus increases the conversion of the acetate into the more reactive perchlorate, hence the second-order rate coefficients increase. Decreasing the concentration of mercuric perchlorate will, however, decrease the concentration of free perchloric acid and this effect will be particularly marked since solvation of the perchlorate produces two equivalents of perchloric acid the second-order rate coefficients will, therefore, decrease. In both cases, substitution changes the concentration... 

From this equilibrium it follows that 0.1 M sodium perchlorate will produce 6x10"5 M perchloric acid, i.e. sufficient to produce a significant acceleration for mercuration with mercuric acetate in the absence of added perchloric acid, but not otherwise. The acceleration of the rate of mercuration with mercuric perchlorate in 97 % aqueous acetic acid (but not with acetic acid containing a concentration of water of 0.2 M) was attributed to the fact that in the former... 

Even more scrambling was found in trifluoroacetolysis of 1-propyl l- " C-mercuric perchlorate. " However, protonated cyclopropane intermedi... 

Mercuric perchlorate has been shown to attack cyclohexanone, the reaction being zero-order in the salt and the rate being that of enolisation with a primary kinetic isotope effect of the same magnitude, to give a mercurated ketone ... 

This sequence had earlier been worked out on model substrates (82JA6092). Treatment of (142) with 1 eq of silver perchlorate in dichloro-methane at room temperature resulted in clean intramolecular cyclization to (143) in 60 -93% yield. Alternatively, the silyl-protected precursor (144) could be directly converted to (143) in one step by treatment with phenyl-mercuric perchlorate for 2-3 min at room temperature. 

The catalysis of the cleavage of carbon-halogen bonds by complexation with metal ions such as silver or mercuric ion is a well-known phenomenon. The compounds susceptible to this action are alkyl halides capable of forming car-bonium ions. The complexed anions such as in mercuric nitrate, mercuric perchlorate, or hydrated mercuric ion do not exhibit a simple relationship between their effect on the total rate and on the relative distribution of products stemming from water or the anion. This evidence is indicative of the following catalytic mechanism ... 

In contrast to this demonstration of bimolecularity, Hall and Lueck82 showed the possibility of acylium ion formation from benzoyl chloride by its reaction with mercuric perchlorate. In common with dimethylcarbamyl chloride, dimethylsulphamyl and tetramethyldiamidophosphochloridate, benzoyl chloride reacted readily to form the corresponding acylium ion /i-butyl chloroformate however was inert. Kivinen138 studied the effect of mercuric chloride on the ethanolysis of 4-methoxybenzoyl chloride, benzoyl chloride and 4-nitrobenzoyl chloride and obtained the following approximate relative rates for the effect of mercuric chloride (0.30 M) in ethanol, 4-MeO, 2.91 4-H, 1.00 4-NOz, 1.03, confirming the SN2 character of the 4-nitro-... 

Most work on aminomercuration has employed secondary aliphatic amines, or primary or secondary anilines. Primary amines have been successfully employed using mercuric perchlorate or mercuric nitrate.197 No reactions utilizing ammonia have been reported. While excess amine or various ether solvents can be used, it is sometimes desireable to add water.198 199... 

Korinek and Halpern (50) report that solutions of mercuric perchlorate are reduced by hydrogen about ten times more rapidly than is mercuric acetate, and that the product mercurous perchlorate is itself reducible to mercury by a slower, homogeneous reaction with hydrogen. The total rate of reaction of hydrogen is given by the equation... 

The principle methods of mercuriation involve reaction of an aromatic with either mercuric acetate (both in the presence and absence of a protic acid), mercuric chloride, or mercuric perchlorate [72MI2( 186)]. The for-... 

Even more scrambling was found in trifluoroacetolysis of 1-propyl-l- C-mercuric perchlorate. " However, protonated cyclopropane intermediates accounted for < 1 % of the products from diazotization of labeled isobutyla-mine and from formolysis of labeled 1-propyl tosylate. ... 

Elemental analysis of duplicate samples of econazole nitrate was performed using a Perkin-Elmer 2400 CBN analyser. Approximately 3-mg quantities of material were combusted and measured against an acetanilide standard. The chlorine determination was based on oxygen flask combustion followed by titration against mercuric perchlorate which had been standardized against sodium chloride and chlorobenzoic acid. The oxygen content of the samples was calculated by difference. 

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