Mercury reactivity

Many varieties of homobifunctional, sulfhydryl-reactive cross-linkers have been synthesized and described in the literature. Some have been based on bis-mercurial salts (Edsall et al., 1954 Edelhoch et al., 1953 Kay and Edsall, 1956 Singer et al., 1960 Mandy et al., 1961). Such mercurial reactive groups also have been used in reversible covalent chromatography applications to purify sulfhydryl-containing pro-... 

Elemental Mercury Reactive Mercury Particulate Mercury Cinnabar... 

Despite its electrode potential (p. 98), very pure zinc has little or no reaction with dilute acids. If impurities are present, local electrochemical cells are set up (cf the rusting of iron. p. 398) and the zinc reacts readily evolving hydrogen. Amalgamation of zinc with mercury reduces the reactivity by giving uniformity to the surface. Very pure zinc reacts readily with dilute acids if previously coated with copper by adding copper(II) sulphate ... 

The metal is slowly oxidised by air at its boiling point, to give red mercury(II) oxide it is attacked by the halogens (which cannoi therefore be collected over mercury) and by nitric acid. (The reactivity of mercury towards acids is further considered on pp. 436, 438.) It forms amalgams—liquid or solid—with many other metals these find uses as reducing agents (for example with sodium, zinc) and as dental fillings (for example with silver, tin or copper). 

The occurrence of a hydrogen isotope effect in an electrophilic substitution will certainly render nugatory any attempt to relate the reactivity of the electrophile with the effects of substituents. Such a situation occurs in mercuration in which the large isotope effect = 6) has been attributed to the weakness of the carbon-mercury bond relative to the carbon-hydrogen bond. The following scheme has been formulated for the reaction, and the occurrence of the isotope effect indicates that the magnitudes of A j and are comparable ... 

Alkynyl anions are more stable = 22) than the more saturated alkyl or alkenyl anions (p/Tj = 40-45). They may be obtained directly from terminal acetylenes by treatment with strong base, e.g. sodium amide (pA, of NH 35). Frequently magnesium acetylides are made in proton-metal exchange reactions with more reactive Grignard reagents. Copper and mercury acetylides are formed directly from the corresponding metal acetates and acetylenes under neutral conditions (G.E. Coates, 1977 R.P. Houghton, 1979). 

Mercury and tin in complexes (68 or 69) (Scheme 32 (154 mav behave as electrophilic centers (155. 156). Under basic conditions, the reactive species is an ambident anion (70) (Scheme 33). 

Dry chlorine reacts with most metals combustively depending on temperature alurninum, arsenic, gold, mercury, selenium, teUerium, and tin react with dry CI2 in gaseous or Hquid form at ordinary temperatures carbon steel ignites at about 250°C depending on the physical shape and titanium reacts violendy with dry chlorine. Wet chlorine is very reactive because of the hydrochloric acid and hypochlorous acid (see eq. 37). Metals stable to wet chlorine include platinum, silver, tantalum, and titanium. Tantalum is the most stable to both dry and wet chlorine. 

Sulfur Polymer Cement. SPC has been proven effective in reducing leach rates of reactive heavy metals to the extent that some wastes can be managed solely as low level waste (LLW). When SPC is combined with mercury and lead oxides (both toxic metals), it interacts chemically to form mercury sulfide, HgS, and lead sulfide, PbS, both of which are insoluble in water. A dried sulfur residue from petroleum refining that contained 600-ppm vanadium (a carcinogen) was chemically modified using dicyclopentadiene and oligomer of cyclopentadiene and used to make SC (58). This material was examined by the California Department of Health Services (Cal EPA) and the leachable level of vanadium had been reduced to 8.3 ppm, well below the soluble threshold limit concentration of 24 ppm (59). 

SuIfona.tlon, Sulfonation is a common reaction with dialkyl sulfates, either by slow decomposition on heating with the release of SO or by attack at the sulfur end of the O—S bond (63). Reaction products are usually the dimethyl ether, methanol, sulfonic acid, and methyl sulfonates, corresponding to both routes. Reactive aromatics are commonly those with higher reactivity to electrophilic substitution at temperatures > 100° C. Tn phenylamine, diphenylmethylamine, anisole, and diphenyl ether exhibit ring sulfonation at 150—160°C, 140°C, 155—160°C, and 180—190°C, respectively, but diphenyl ketone and benzyl methyl ether do not react up to 190°C. Diphenyl amine methylates and then sulfonates. Catalysis of sulfonation of anthraquinone by dimethyl sulfate occurs with thaHium(III) oxide or mercury(II) oxide at 170°C. Alkyl interchange also gives sulfation. 

Reactivity. Bromine is nonflammable but may ignite combustibles, such as dry grass, on contact. Handling bromine in a wet atmosphere, extreme heat, and temperatures low enough to cause bromine to soHdify (—6° C) should be avoided. Bromine should be stored in a cool, dry area away from heat. Materials that should not be permitted to contact bromine include combustibles, Hquid ammonia, aluminum, titanium, mercury, sodium, potassium, and magnesium. Bromine attacks some forms of plastics, mbber, and coatings (62). 

A third form of cadmium pigments includes the mercury cadmiums. Mercuric sulfide (HgS) forms soHd solutions up to about 20 mol % with the oranges, reds, and maroons. The heat stabiUty is improved up to 370°C, and the costs are somewhat lower than the CP grades. The mercury cadmiums are slightly more reactive, but have excellent bleed resistance. 

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. 

Chemical Reactivity - Reactivity with Water Dissolves to form an alkaline solution. The reaction is non-violent Reactivity with Common Materials Forms explosion-sensitive materials with some metals such as lead, silver, mercury, and copper Stability During Transport Stable but must not be in contact with acids Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Mercury(II) trifluoroacetate is a good electrophile that is highly reactive toward carbon-carbon double bonds [52, 53, 54] When reacting with olefins in nucleophilic solvents, it usually gives exclusively mercurated solvoadducts, but never products of skeletal rearrangement Solvomercuration-demercuratton of alkenes with mercury(II) trifluoroacetate is a remarkably effective procedure for the preparation of esters and alcohols with Markovnikov s regiochemistry [52, 5J] (equation 24)... 

A similar replacement of the oxygen heteroatom by sulfur to thia-pyrylium salts (25, X = S) can occur on treatment with Na2S or NaSH. By making use of the difference in reactivity between OAlk and SAlk groups and of the strong complexation of RSH wdth mercury salts, Arndt et Traverse,Wizinger and Ulrich,... 

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