Hg -salts

Substitution of caiboxylic groups by halogen via Ag saHs (Hunsdiecker, Borodin) or Hg salts (Cnstol-Rrth)... 

PhHgOAc 1.2 eq., MeOH-CH2Cl2 (4 1), 96% yield. The resulting Hg salt is liberated with H2S. ... 

The Minamata disaster in Japan, when 52 people died in 1952, occurred because fish, which formed the staple diet of the small fishing community, contained abnormally high concentrations of mercury in the form of MeHgSMe. This was found to originate from a local chemical works where Hg salts were used (inefficiently) to catalyse the production of... 

Na hydroxide first forms the Na salt of NMe, then the Na salt of methazonic acid, and finally the Na salt of nitroacetic acid (Ref 10). 5) With Hg(ll) chloride is formed first the Hg salt of NMe which rearranges and dehydrates to MF (Ref 10). 

Hg Salt. It is prepd by the action of Hg(ll) monoxide In eth on the free nitro compd, yield 86%, mp 147° (Ref 6). It reacts with K hydroxide or K iodide to give the K salt of fluorodi-nitromethane, and with H chloride or w to regenerate the free nitro compd (Ref 3)... 

CA Registry No 22632-21-9. It is prepd by the action of I in anhyd eth on the Hg salt of fluorodinitromethane, yield 74% (Ref 3). The thermal decompn was studied betw 160 and 197°. The plot of log k vs 1/T gave a straight line from which the activation energy was calcd as 39.7kcal/mole (Ref 2)... 

Hg Salt. Colorl crysts, slightly sol in org solvs prepd by the action of Hg oxide on an eth soln of TNMe (Ref 4). It reacts with olefins to form adducts contg one or 2 trinitromethyl groups, depending on reactant ratios (Ref 33). The ionization const in w at 25° is 6.04 x 10 3 (Ref 50)... 

Explds violently on contact with Cu oxide and is friction sensitive. Its Hg salt is also an expl Refs 1) Beil 25, 114 2) D.D. Phillips ... 

The Na salt may serve for the prepn of free iso-oxytetrazole, as well as its salts, such as Mercury salt. White solid, expl. Can be prepd by treating the Na compd with a sol Hg salt Silver salt. White solid, expl. Can be prepd by treating the Na compd with a Ag salt Refs 1) Beil 26, (109) 2) F.C. Palazzo, AitiR-... 

Preparation. The anhyd salt is prepd by the addn of a soln of perchloric ac in trifluoroacetic ac to that of a Hg salt in the same solv, followed by careful evapn of the solv until crysts form (Ref 2)... 

Opinions differ on the nature of the metal-adsorbed anion bond for specific adsorption. In all probability, a covalent bond similar to that formed in salts of the given ion with the cation of the electrode metal is not formed. The behaviour of sulphide ions on an ideal polarized mercury electrode provides evidence for this conclusion. Sulphide ions are adsorbed far more strongly than halide ions. The electrocapillary quantities (interfacial tension, differential capacity) change discontinuously at the potential at which HgS is formed. Thus, the bond of specifically adsorbed sulphide to mercury is different in nature from that in the HgS salt. Some authors have suggested that specific adsorption is a result of partial charge transfer between the adsorbed ions and the electrode. 

In a way related are the complexes formed by Hg salts and multicrown dendrimers of different generations (dendrimers with a polypropylene amine interior of different volume and benzo[15]-crown-5 ether periphery), studied by extraction methods using radioactive 203Hg2+.210 Up to 12 Hg2+ ions were found to be bound per dendrimer molecule, obviously in the amine-dominated interior, not in the crown-ether periphery. 

Terminal alkynes are less reactive than internal alkynes towards the acid-catalysed addition of water. Therefore, terminal alkynes require Hg salt (HgS04) catalyst for the addition of water to yield aldehydes and ketones. Addition of water to acetylene gives acetaldehyde, and all other terminal alkynes give ketones. The reaction is regioselective and follows Markovni-kov addition. For example, 1-butyne reacts with water in the presence of H2SO4 and HgS04 to yield 2-butanone. 

Hg-salt catalyzed 1,3-transposition of transition metal-catalyzed Clasien re-... 

Its Mercury salt, HgfCj N302)2- sulfur-yel crysts (from eth), mp 123° (dec), sol in hot eth was obtd by reaction of the methyl ester with yel HgO, under cooling. This salt is probably expl (Compare with Hg salt of ethyl ester)... 

In the early works, Hg salts were often used in place of the Ag salts to initiate the reaction. This has been called the Zemplen-Helferich modification. 

An improvement over the traditional method to avoid use of Hg salts. 

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