Mercuric chloride, addition complex with

Mercuric chloride in methanol also reacts with compounds 8 (in dichloro-methane), forming colorless mercury complexes, which can in turn be reconverted to the cyanines 8. Such addition compounds are stable only as solids, decomposing rather quickly in solution. Mercuric acetate in methanol reacts rapidly with the formation of elemental mercury, where by the phosphamethin-cyanines are destroyed uniform products from this reaction have not as yet been isolated. 

Dithiocoumarins (50) are generally prepared by treatment of thiocoumarins with phosphorus pentasulfide, isolation being best effected by formation of a mercury complex by addition of mercurous chloride, followed by decomposition of this complex with sodium sulfide. An alternative ring-closure approach involves heating o-allylphenols (49) with sulfur in... 

An official procedure [10,11] describes a method for the determination of chloride in a saturated calcium sulfate extract of soil. The extract is acidified and the concentration of chloride is determined by titration with mercuric nitrate using diphenylcarbazone as indicator. Mercuric ion in the presence of chloride forms mercuric chloride, which, although soluble, provides insufficient mercuric ion to form the mercuric-diphenylcarbazone complex. When all of the chloride has been removed in this way, addition of further mercuric ion produces the violet complex. 

From the kinetics standpoint, the reaction rate is of the first order in relation to each of the reactants employed. It implies the formation of a a complex, by the addition of mercuric chloride to acetylene, followed by transformation to mercuric chloroviny chloride. The action of hydrochloric add then regenerates the mercuric chloride with the formation of vinyl chloride ... 

So far we have considered the adsorption to be influenced solely by attractive forces to the carbon surface, but often of equal or even greater significance are the forces that solutes can exert on solution status of one another. Potassium iodide increases the solubility of iodine in water and thereby reduces the adsorption of iodine. Conversely, the adsorption of fatty acids is increased when the solubility is reduced by the addition of sodium chloride. The effect on fatty acids is in sharp contrast to that observed with mercuric chloride. The adsorption of mercuric chloride may be diminished 60% when sodium chloride is present this action is ascribed to the formation of a weakly adsorbable complex, Na2HgCI4.28... 

As early as 1963, Tsuji and colleagues described the reaction of olefin-palladium chloride complexes with CO to produce jS-chloroacyl chlorides [1,2]. Both internal and terminal aliphatic olefins were transformed into the corresponding chloroesters when the reaction was conducted in alcohols. Later on, in 1969, Yukawa and Tsutsumi reported on the reaction of a styrene-palladium complex with CO in alcohols [3]. Here, various cinnamates and phenylsuccinates were synthesized. Compared with Tsuji s work, they proposed a different reaction mechanism. They assumed that the oxidative addition of the alkyloxycarbonyl groups into styrenes is the key step, but a stoichiometric amount of palladium was stiU necessary to perform the reaction. Another version of a dialkoxycarbonylation of olefins was reported by Heck [4], using mercuric chloride as additive. 

These structure determinations show that thioethers and saturated cyclic sulphur compounds do not form addition compounds with HgCI as has previously been believed. The complexes formed are the result of a substitution reaction, in which one of the chlorine atoms in HgCl has been replaced by the sulphur atom of the donor molecule giving rise to positively charged mercuric complexes and negative chloride ions. The configuration of ligands around mercury in these complexes is intermediate in character between that of tetrahedrally and octahedrally coordinated mercury. 

Dimethyltetrazole. To a mixture of 35 g. (0.814 mole) of hydra-zoic acid dissolved in about 500 cc. of benzene and 50 cc. of concentrated sulfuric acid, 15.7 g. (0.27 mole) of acetone is added dropwise with stirring and cooling. Approximately 5 1. of nitrogen is evolved. The acid layer is then diluted with ice and neutralized with sodiiun carbonate, and ethanol is added to precipitate the sodium sulfate. After filtration, the solution is concentrated and the mercuric chloride complex of the reaction product is obtained by adding a cold saturated aqueous solution of mercuric chloride. The addition compound melts at 111°. The free... 

The liberated hydrochloric acid can be determined in the presence of boric acid. The reaction of the ammonium salt with mercuric chloride added in excess is carried out in acetone. Then a known quantity of a standard sodium hydroxide certainly in excess is added in water. The excess of base that has not been neutralized by the formed hydrochloric acid is titrated with a standard acid solution. During the course of the titration— more precisely after the addition of the sodium hydroxide—an iodide solution is added. The complex tetraiodomercurate(II) forms, which precludes any interference with the dichloromercury(II) in excess. Due to the stability constants of the possibly existing complexes, it is indeed the following reaction that takes place ... 

This equation has a standard electrode potential of -0.447 V. Thus, the solution containing mercuric and chloride ions in contact with iron forms a battery. The reduction of the complex ions to metallic mercury is the cathodic reaction. The dissolution of iron is the anodic reaction. The overall reaction in the battery is given by the addition of Equation (13.42) and Equation (13.43). Due to the high value of its reversible cell voltage under standard conditions (0.85 V), it is expected that a very low equilibrium concentration of the complex ion can be achieved. 

The ASTM and AOCS standards specify determination of molecular weight by titration after addition of mercuric acetate. Mercuric ion complexes halides, resulting in the replacement of halide ions in solution with acetate ion. Acetate is titrated potentiometrically with perchloric acid in acetic acid solvent. The method is valid if a correction is made for the concentration of any halides not associated with the quaternary amine, for example, sodium chloride. 

---