Sodium tetraphenyl borate

Discussion. Potassium may be precipitated with excess of sodium tetraphenyl-borate solution as potassium tetraphenylborate. The excess of reagent is determined by titration with mercury(II) nitrate solution. The indicator consists of a mixture of iron(III) nitrate and dilute sodium thiocyanate solution. The end-point is revealed by the decolorisation of the iron(III)-thiocyanate complex due to the formation of the colourless mercury(II) thiocyanate. The reaction between mercury( II) nitrate and sodium tetraphenylborate under the experimental conditions used is not quite stoichiometric hence it is necessary to determine the volume in mL of Hg(N03)2 solution equivalent to 1 mL of a NaB(C6H5)4 solution. Halides must be absent. 

Materials Required Benzethonium chloride 0.15 g Chloroform 50 ml bromophenol blue solution (Dissolve with heating 0.2 g of bromophenol blue in 3 ml of 0.1 M NaOH and 10 ml of ethanol (96%). Allow to cool and dilute to 100 ml with ethanol 96%] 50 ml sodium tetraphenyl borate solution (1% w/v in chloroform) 50 ml sintered-glass crucible No 4. 

A mixture consisting of 25 mL of an aqueous (0.2 to 1.0 mM) solution of chlorpromazine hydrochloride and 5 mL of 0.1 M acetate buffer (pH 3.3) was titrated to a potentiometric endpoint with 0.0 IM sodium tetraphenyl-borate [77]. The titrant was added at a rate of 0.36 mL/min with continuous stirring, and the temperature of the medium was maintained at 22 2°C. The end point was detected by a tetraphenylborate-selective electrode. 

Crown-ether network polymers have also been prepared by adding to a slurry of NaH in THF, an equimolar amount of the appropriate hydroxy-containing crown-ethers followed by the addition of chloromethylated cross-linked polystyrene. Binding of Na, K, Cs picrates and of sodium tetraphenyl-borate to the immobilized crown-ether is achieved under simple conditions [74]. 

The construction and electrochemical response characteristics of poly (vinyl chloride) membrane sensors for donepezil HC1 are described. The sensing membranes incorporate ion association complexes of donepezil HC1 cation and sodium tetraphenyl borate (sensor 1), or phospho-molybdic acid (PMA) (sensor 2), or phosphotungstic acid (sensor 3) as electroactive materials. The sensors display a fast, stable, and near-Nemstian response over a relative wide donepezil HC1 concentration... 

Paper partition chromatographic methods have been widely applied to the analysis of tetracyclines (128, 129). Pharmaceutical aqueous suspensions for oral use are acidified with HC1 and diluted with methanol. Crystalline formulations are dissolved only in methanol. A paper chromatographic method for TC determination in pharmaceutical preparations is based on the complexation of the antibiotic with a mixture of urea and disodium edetate on paper at pH 7.4. Urea helped in the separation of degradation products and led to the formation of well defined spots (130). Samples from fermentations must be acidified with oxalic acid to liberate TC from the mycelium. TC in filtrates may be precipitated in saturated solution of sodium tetraphenyl borate, precipitate dissolved in ethyl or butyl acetate and applied for paper chromatography. Various solvent systems and hRp values for paper chromatography are given in Table 4. 

Quercetin-sodium tetraphenylborate A mixture of quercetin (0.015% in methanol) and sodium tetraphenyl-borate (1% in n-butanol saturated with water) is sprayed on the plate to yield orange/red spots. 

The piperidine derivative (111) has been reported109 from the reaction of piperidine and 112 in acetic acid with sodium tetraphenyl-borate. The piperidine derivative (113) arises from a displacement of... 

Figure 46. Solvent dependence of the partial molar heat capacity of sodium tetraphenyl-borate in t-butyl alcohol + water mixtures at 298 K as a function of alcohol mole fraction, xj (Arnett and McKelvey, 1966b).

Figure 10.6. Rate of anionic polymerization of styrene initiated by sodium naphthalene in 3-methyl tetrahydrofuran at 20°C. Left linear variation of rate with (C°)l/2 right inverse linear variation of rate with concentration of Na+ in presence of added sodium tetraphenyl borate. (Data from Schnitt and Schulz [79].)...

Funt and Blain reported the electropolymerisation of isobutyl vinyl ether in methylene chloride with various tetrabutylammonium salts and showed the unmistakably cationic character of the chain carriers in these processes. Similar studies by Mei oli and Vidotto " extended the range of monomers and solvents with sodium tetraphenyl borate as background electrolyte. The anodic initiation mechanism was postulated as a two-electron process ... 

Purine itself, on macroscale reduction at a mercury cathode in acetic or hydrochloric acid, is reduced to 1,6-dihydropurine, isolated as a complex with sodium tetraphenyl borate. ... 

Consecutive reaction of the dithiocarbamate (222) with concentrated sulfuric acid and with sodium tetraphenyl borate gave (223) in 86% yield (Equation (36)) <80AHC(27)l5l>. 

It is useful to consider how the presence of excess counterion due to the addition of a strongly dissociating salt (e.g., sodium tetraphenyl borate. 

Problem 8.11 Polymerization of styrene with sodium naphthalene initiator was performed at 25°C in tetrahydrofuran (THF) using a static technique [8] that is suitable for monitoring fast reactions. The conversion was determined by monitoring the residual styrene monomer spectrophotometrically during polymerization and the concentration of living ends [M ] was determined spectrophotometrically at the end of the experiment. In independent experimental series, the overall rate constant kp was obtained [cf. Eq. (P8.10.2)] both at different concentrations of initiator (and hence [M ]) without addition of electrolyte and at different concentrations of sodium ions from externally added sodium tetraphenyl borate (NaBPh4) salt and constant concentration of initiator. The data are given below ... 

Let us now consider how the presence of excess counterion due to the. addition of a strongly dissociating salt (e.g., sodium tetraphenyl borate, NaBPh4, to supply excess Na" ") can affect the kinetics of a living anionic polymerization. The retarding effect of a dissociating salt forms the basis of a method by which the dissociation constant of a polymeric ion pair may be determined. 

Materials. The commercial grade Exxpro elastomer, BrXPSO (Exxon Chemical Co., Baytown, TX), triphenyl phosphine(Aldrich F. Wt. 262.29, M.P. 79-81 C), sodium tetraphenyl borate(Aldrich, 99.5+ %), tetrahydrofiiran(Baker, reagent grade), methanol and isopropanol(Baker, reagent grade) were purchased and were used as such. 

See Sodium octoxynol-2 ethane sulfonate Sodium 3,6,9,12-tetraoxaoctadecanoate. See Sodium hexeth-4 carboxylate Sodium 3,6,9,12-tetraoxatetracosanoate. See Sodium laureth-4 carboxylate Sodium tetraphenyl borate. See Sodium tetraphenylboron Sodium tetraphenylboron CAS 143-66-8 EINECS/ELINCS 205-605-5 Synonyms Sodium tetraphenyl borate Tetraphenylboron sodium Classification Boranes Empirical C24H2oBNa Properties M.w. 342.23 Toxicology Irritant TSCA listed Storage Light-sensitive... 

If, however, the experiment is carried out with constant monomer and variable initiator concentration, the calculated value of kp, obtained via Equation (18-13), decreases with increasing initiator concentration. The calculated rate constant decreases still further on adding other salts with the same gegenion, i.e., sodium tetraphenyl borate (Kalignost) which is readily soluble in tetrahydrofuran, until it finally reaches a constant limiting value for very high added salt concentrations, [added salt] [C ]. From this, it is seen that at least two kinds of active species are present, presumably ion pairs P Na and free ions P . Thus, the observed rate constant is a mean value, and Equation (18-13) must be modified to... 

Dissolve 5 g sodium tetraphenyl borate Na(B(C6H5)z ) in water and make up to 1000 ml. 

Heat to 50 C and treat with 20 ml sodium tetraphenyl borate solution. 

Procedure. The reaction is conducted in a quartz crucible. A small portion of the powdered sample is treated with about 5-10 times the quantity of zinc chloride and a drop of water. After evaporation, the crucible is covered and the contents heated for five minutes over a bare flame. The cooled mass is stirred with a drop or two of hot water, the suspension is transferred to a conical tube, and centrifuged. One drop of the clear liquid is treated with a drop of a 1 % aqueous solution of sodium tetraphenyl borate. If potassium is present, a white precipitate or turbidity appears. 

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