Mercuric hydroxide complexes

Matteson and Kramer11 suggested that a glycerol ester of the boronic acid is converted into a hydroxide complex, as in equation (6), and this complex is then attacked by mercuric chloride in the rate-determining step (7). 

Qualitative. The classic method for the quaUtative determination of silver ia solution is precipitation as silver chloride with dilute nitric acid and chloride ion. The silver chloride can be differentiated from lead or mercurous chlorides, which also may precipitate, by the fact that lead chloride is soluble ia hot water but not ia ammonium hydroxide, whereas mercurous chloride turns black ia ammonium hydroxide. Silver chloride dissolves ia ammonium hydroxide because of the formation of soluble silver—ammonia complexes. A number of selective spot tests (24) iaclude reactions with /)-dimethy1amino-henz1idenerhodanine, ceric ammonium nitrate, or bromopyrogaHol red [16574-43-9]. Silver is detected by x-ray fluorescence and arc-emission spectrometry. Two sensitive arc-emission lines for silver occur at 328.1 and 338.3 nm. 

Perhydropyrido [ 1,2-a]pyrimidine was oxidized with the mercuric acetate-EDTA complex. When the reaction mixture was treated with potassium carbonate, 3,4,6,7,8,9-hexahydro-2//-pyrido[l,2-a]pyrimidine was obtained, whereas on work-up with 20% sodium hydroxide the product was l-(3-aminopropyl)-2-oxopiperidine.344... 

Formation of Complex Ions.—In certain cases the solubility of a sparingly soluble salt is greatly increased, instead of being decreased, by the addition of a common ion a familiar illustration of this behavior is provided by the high solubility of silver cyanide in a solution of cyanide ions. Similarly, mercuric iodide is soluble in the presence of excess of iodide ions and aluminum hydroxide dissolves in solutions of alkali hydroxides. In cases of this kind it is readily shown by transference measurements that the silver, mercury or other cation is actually present in the solution in the form of a complex ion. The solubility of a sparingly soluble salt can be increased by the addition of any substance, whether it... 

Mercuric sulfide is soluble in a solution of sodium sulfide and sodium hydroxide (to repress hydrolysis of the sulfide, vhich vould decrease the sulfide ion concentration), but not in a solution of ammoniunt sulfide and ammonium hydroxide, in which the sulfide-ion concentration is smaller. The other suWdes listed are soluble in both solutions. CuS, AgoS, BioSg, CdS, PbS, ZnS, CoS, NiS, FeS, MnS, and SnS are not soluble in sulfide solutions, but most of these form complex sulfides by fusion with NhoS or KoS. Although SnS is not soluble in Na S or (NH4)oS solutions, it dissolves in solutions containing both sulfide and disulfide, Na- S. or (NH4)2S2, or sulfide and peroxide. The disulfide ion. So—, or peroxide oxidizes the tin to the stannic level, and the sulfostannate ion is then formed ... 

A spectrophotometric method for the determination of ampicillin involving initial benzoylation of the side chain a-amino group is described. a-Benzamidobenzylpenicillin so formed is treated with mercuric chloride in acid solution and a-benzamidobenzylpenicillenic acid is obtained. This may be assayed spectrophoto-metricallyl69, Ampicillin is degraded in a buffer solution at pH 5.2 at 75°C and the absorbance is measured at 320 nm. Smith s method for the spectrophotometric determination of ampicillin was adapted to the assay of ampicillin in chicken blood, bile and urine 3-Ampicillin is dissolved in 5N sodium hydroxide and the absorbance is measured at 279 nm 2, Ampicillin is determined spectrophotometrically as its copper complex S. Spectrophotometric and circular dichroism methods for determining the activity of ampicillin are described. A... 

Based on many experimental details, it is strongly believed that olefins form a coordination complex with mercuric salts in solution, which can decompose to release olefins again. As only 10 outer electrons are available for Hg +, the complexes from olefin and mercuric halides that do not have a stable 18-electron configuration require additional ligands of hydroxide in aqueous solution for comparison, the complexes from olefin and mercuric acetate are stable because acetate is bidental. Olefin is activated as of coordination, so that the formation of an addition product is quite possible. A tentative mechanism is outlined here to show the dynamic equilibrium between the coordination complex and the addition product. 

Note 6. Modification of ammonia recovery stage when mercury containing catalysts are used for digestion. Low ammonia recoveries result during steam distillation from sodium hydroxide when mercury containing catalysts are used in the Kjeldahl digestion. This is due to the partial formation of a mercuric-amine which is not completely decomposed by sodium hydroxide. The addition of a mixture of sodium hydroxide and sodium thiosulfate completely degrades this complex and quantitative ammonia recoveries result. 

Alkaline hydroxides yield a yellow precipitate of mercuric oxide HgO as early as pH > about 2.4. Ammonia transforms it into a yellow complex named Millon s base, with the formula [Hg2N(0H)(H20)2]. The latter, with dichloromercure(II) (wrongly called mercuric chloride ), yields white precipitate with the formula [Hg(NH2)Cl], which is called an infusible white precipitate because it volatilizes without melting. The corresponding reactions are... 

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 ... 

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