Silver salt , removal

N-methyl-4piperidyl benzilate methobromide To a suspension of 0.15 mol of freshly prepared silver bromide in 300 ml of anhydrous methanol is added a solution of 0.1 mol of quaternary iodide obtained as above. The mixture is stirred and refluxed for several hours after which time transhalogenation is complete. The mixture is cooled, the insoluble silver salt removed by filtration and the methanolic solution of the quaternaty bromide is concentrated in vacuo. The residue is recrystallized from methanol or methanol-ether yielding the quaternary bromide in quantitative amounts, melting point 237°C to 238°C. 

Argentometric titration method has been applied to the determination of sulfonamide mixtures. The sulfonamides are quantitatively precipitated by the addition of excess standard silver nitrate solution, the precipitated silver salts removed by filtration, and the excess silver nitrate titrated with standard ammonium thiocyanate using ferric alum as indicator (32). 

Fieser s solution An aqueous alkaline solution of sodium anthraquinone -sulphonale (silver salt) reduced with sodium dithionite, Na2S204, and used as a scrubbing solution for partially removing O2 from, e.g., N2. 

Saccharic acid. Use the filtrate A) from the above oxidation of lactose or, alternatively, employ the product obtained by evaporating 10 g. of glucose with 100 ml. of nitric acid, sp. gr. 1 15, until a syrupy residue remains and then dissolving in 30 ml. of water. Exactly neutralise at the boiling point with a concentrated solution of potassium carbonate, acidify with acetic acid, and concentrate again to a thick syrup. Upon the addition of 50 per cent, acetic acid, acid potassium saccharate sepa rates out. Filter at the pump and recrystaUise from a small quantity of hot water to remove the attendant oxahc acid. It is necessary to isolate the saccharic acid as the acid potassium salt since the acid is very soluble in water. The purity may be confirmed by conversion into the silver salt (Section 111,103) and determination of the silver content by ignition. 

For Volhard methods identified by an asterisk ( ) the precipitated silver salt must be removed before carrying out the back titration. 

A considerable amount of sodium nitrate is present in the precipitate. Although the presence of sodium nitrate did not hinder small-scale alkylation reactions (ca. 250 mg.), the submitters recommend that it be removed in larger runs to facilitate the isolation and drying of the silver salt. 

CH3OH)]2 has a distorted square-pyramidal zinc center with the iodide in the apical position and a Zn—Ba distance of 3.736(1) A. The iodide can be removed by treatment with a silver salt. 

A more conventional pathway uses the halide complexes (RNC)AuX which are reacted with 1 equiv. of the isocyanide, preferentially in the presence of a silver salt (AgS03CF3, AgBF4) for removal of the halide X as AgX (Equation (44)).222... 

Tyree and Bynum [132] described an ion chromatographic method for the determination of nitrate and phosphate in seawater. The pre-treatment comprised vigorous mixing of the sample with a silver-based cation-exchange resin, followed by filtration to remove the precipitated silver salt. 

The imidazole complex raras-[Ir(imid)2Cl4]- is stable for days in neutral aqueous solution, and for hours in the presence of added thiocyanate. Addition of silver nitrate precipitates the silver salt of the complex, with no indication of Ag+-catalyzed removal of coordinated chloride. Thus this iridium(III) complex is substitutionally much more inert than its much-studied (because (potentially) anti-tumor) ruthenium(III) analogue (96). 

A pad of Florisil is employed to facilitate removal of the suspended silver salts. 

Research in this area was developed further by Li et at. using 1,3-dienes 64 for the gold-catalyzed annulation of phenols and naphtols [58, 59]. These generated various dihydrobenzofuran derivatives. The best yields were achieved when the catalytic system included enough AuCl3 and silver salt to remove halogen atoms and deliver cationic gold. 

A solution of 82.2 g. (0.2 mole) of acetobromoglucose1 (Note 1) in 125 ml. of dry acetone (Note 2) in a 250-ml. flask is cooled to 0° in an ice bath. To the cold solution is added 2.3 ml. of water and then 46.5 g. (0.17 mole) of silver carbonate (Note 3) in small portions in the course of 15 minutes. The mixture is shaken well during the addition and for 30 minutes longer (Note 4). The mixture is then warmed to 50-60° and filtered. The mass of silver salts is washed with 65 ml. of dry acetone (Note 5), removed from the funnel, warmed in a flask with 65 ml. more of acetone, filtered, and washed again on the funnel. 

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