Tetraphenylarsonium Chlorid

Tetraphenylarsonium chloride (107,108) has also been used for the precipitation of the perchlorate ion in gravimetric analysis. 

Determination as the tetraphenylarsonium compound Discussion. Any ions forming a precipitate with tetraphenylarsonium chloride (e.g. MnO, ClOj, Br , I-, I03 and SCN-) will interfere. Difluorophosphates give slight interference which can be overcome by boiling the solution for a few minutes to hydrolyse difluorophosphate the hexafluorophosphate ion is not affected by this treatment. 

Tetrabutylammonium hydroxide 716 Tetraphenylarsonium chloride, 482 Thallium, D. of as thallium(I) chromate,... 

Analytical. It can be titrated with std base to a salmon colored phenolphthalein endpoint and can be quanty pptd from aq solns with tetraphenylarsonium chloride KSp of the complex in w is 6.9 x 10 9 (Ref 22). This procedure can be adapted to the analysis of compds, such as bis-(trinitroethyl) urea, which regenerate... 

It was found that chlorides, chlorates, and nitrates interfere by forming in sol ppts (Ref 6). Later it was found that w sol perchlorates could be analyzed gravimetrically by pptn of the perchlorate ion as tetraphenylarsonium perchlorate (Ksp at 20° = 2.60 0.14 x 10"9). The ppt can be (Tried at 105° and weighed directly (Ref 16). Still more recently a specific perchlorate ion electrode has been developed (Ref 17) which can be used for the potentiometric titration of the perchlorate ion using a soln of tetraphenylarsonium chloride as the titrant (Ref 15). Tetra-phenylphosphonium chloride has been similarly used, but the corresponding Sb compd is too insol in w for practical use (Ref 8), For routine assay of perchlorates for use by the armed forces, a Na carbonate fusion procedure is described in Mil Specs MlL-A-23946 (19 Aug 1964) MIL-A-23948 (19 Aug 1964) (see also under Ammonium Perchlorate). The tetraphenylarsonium chloride procedure has also been proposed for use in Mil Specs (Ref 11)... 

The exchange of Mo between the anions Mo(CN)g and Mo(CN)g has been investigated by the isotopic method ( Mo) and the separation methods (a) precipitation of Mo(CN)g with either ethanol or cadmium ions, and (b) precipitation of Mo(CN) with tetraphenylarsonium chloride. Complete exchange was observed by Wolfgang even with reactant concentrations 5x10 M. An estimate of the rate coefficient at 2 °C of >10 l.mole . sec has been sug-geMd. 

Monien and Stangel [598] studied the performance of a number of alternative chelating agents for vanadium, and their effect on vanadium analysis, by atomic absorption spectrometry with volatilisation in a graphite furnace. Two promising compounds were evaluated in detail, namely 4-(2-pyridylazo) resorcinol in conjunction with tetraphenylarsonium chloride and tetramethylenedithiocar-bamate. These substances, dissolved in chloroform, were used for extraction... 

N-methyl-l,2-diphenylethylamine, 34, 64 tetraphenylarsonium chloride hydrochloride, 30, 97 Guanidine, 32, 96 Guanidine hydrochloride, 32, 45 Guanylthiourea, 35, 69 D-GuLONIC ACID, y-LACTONE, 36, 38... 

Acetate, (C6H5)4AsC1, citrate, 2,3-dimercaptopropanol, EDTA, I-, Na5P3O10, SO)-, S20)-, tartrate, tiron, tetraphenylarsonium chloride, triethanolamine, thioglycolic acid Acetylacetone, citrate, CN-, EDTA, I-, NH3, N02, SCN-, S20)-, tartrate, triethanol amine Citrate, CN-, EDTA, I-, NH3, N02, SCN-, S20 -, tartrate, urea Reduction to Pu(IV) with sulfamic acid C20)-, citrate, EDTA, F-, tartrate Oxidation to perrhenate Citrate, tartrate, thiourea CN-, thiourea... 

The first attempt to radiolabel drug particles (instead of polymers like polystyrene or Teflon particles) for pharmaceutical aerosols was carried out on fenoterol and salbutamol by Kohler et al. [12] Scheme 3). However, it was later found that their method would change the particle size distribution of the labelled aerosol, resulting in a coarser aerosol than the imlabelled product. After subsequent improvement by Summers et al. [18] Scheme 4), this method has become widely used for radiolabelling MDIs. It is preferred over other methods as it does not involve extraction with tetraphenylarsonium chloride and chloroform. 

The extraction of Tc (VII) and Tc (IV) from nitric acid has been investigated as function of tetraphenylarsonium chloride concentration in chloroform The ratio KJCf, (distribution coefficient divided by the concentration of tetraphenyl-arsoniiun chloride in the organic phase) is found to be approximately constant. 

Ammonium molybdate is dissolved in a 0.5% solution of NH OH and Tc is extracted by 0.05 M tetraphenylarsonium chloride in chloroform. The phases are separated and chloroform is distilled off. The residue is dissolved in water, and the solution is twice passed through a column of Dowex-50. (CgH5) As is adsorbed by the cation exchanger, while "TcO can be eluted. 

Procedure To the sample which contains 20-300 /xg of pertechnetate in 5-20 ml of solution, are added potassium perchlorate solution (2 ml, 1 mg KCIO per ml) and enough NaCl to make the solution approximately 1 M. The solution is heated and neutralized with ammonia. Pertechnetate is precipitated with aqueous 5 % tetraphenylarsonium chloride reagent. The precipitate is filtered, washed and dried, and a 2-mg portion is mixed with potassium bromide (300 mg). The mixture is pressed to form a clear disc by the usual technique. The infrared spectrum is recorded between 10 and 12 /x. The peak absorption is measured at 11.09 /X by the base-line technique. 

The most popular method involves weighing of the precipitate in the form of tetraphenylarsonium pertechnetate . Precipitation is carried out from neutral or alkaline solution at pH 8-9 by adding an excess of tetraphenylarsonium chloride (CgH5) AsCl. Since the precipitated salt is slightly soluble the total volume of the solution is kept to a minimum. 

The solution of (CgHj) AsTcO is passed through an ion exchange resin in the chloride form. Pertechnetate ions are strongly adsorbed while tetraphenylarsonium chloride is recovered in the runnings. Pertechnetate is then eluted from the resin by 2 N NaOH. Nitron pertechnetate is dissolved in ethyl acetate and the solution is shaken with dilute ammonia. TcO passes into the aqueous layer while the nitron remains in the ester . 

The hydrolysis mixture is transferred to a 1-1. round-bottomed flask fitted with a reflux condenser, and 500 ml. of concentrated hydrochloric acid is added (Note 5). The mixture is heated on a steam bath for 1.5-2 hours. The flask is cooled in an ice bath the crystals are collected on a sintered-glass funnel and washed with 200 ml. of ice-cold concentrated hydrochloric acid and then with 200 ml. of ice-cold dry ether. The crude product weighs 50-56 g. The product is dissolved in a mixture of 50 ml. of water and 150 ml. of concentrated hydrochloric acid by boiling under reflux. The tetraphenylarsonium chloride hydrochloride separates when the solution is cooled in an ice bath. The white needles are collected on a sintered-glass funnel and washed with 50 ml. of ice-cold concentrated hydrochloric acid and then with 200 ml. of ice-cold dry ether. The yield of tetraphenylarsonium chloride hydrochloride melting at 204-208° with decomposition is 42-45 g. (74r-80%). 

The hydrolysis product consists mainly of tetraphenylarsonium bromide, which is converted to tetraphenylarsonium chloride hydrochloride by crystallization from concentrated hydrochloric acid. 

C. Tetraphenylarsonium chloride hydrochloride. In a 2-1. round-bottomed three-necked flask fitted with a condenser, a mercury-sealed mechanical Hershberg stirrer, and a dropping funnel is placed 40 g. (0.124 mole) of triphenylarsine oxide dissolved in 1 1. of hot benzene. To this solution there is added with vigorous stirring a solution of phenylmagnesium bromide which is prepared from 34.6 g. (0.22 mole) of bromobenzene, 6.0 g. (0.25 gram atom) of magnesium, and 200 ml. of dry ether. A brown viscous solid separates. The mixture is stirred for 15 minutes and then stirred and heated under reflux on a steam bath for 30 minutes. The solvent is removed by decantation, and the viscous solid is washed with 500 ml. of benzene. The addition product is... 

Tetraphenylarsonium chloride hydrochloride has been prepared by the action of phenylmagnesium bromide on triphenylarsine oxide. The method described here is essentially that of Blicke and Monroe. ... 

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