Precipitation perchlorate

Eichler and Wahl have attempted an isotopic study ( Os and Os) of the exchange reaction between Os(dipy)3 and Os(dipy)3 using a direct injection technique so that reaction times 7 x 10 sec were possible. With total osmium 10" M in aqueous sulphate media at 0 °C complete exchange was observed. The separation methods used were, (a) perchlorate precipitation (in presence of iron(II) carrier) and (6) extraction with p-toluenesulphonic acid in nitromethane, of the osmium(II) complex. A lower limit of 1 x 10 l.mole. sec was placed on the rate coefficient (0 °C, 3.0 M H2SO4). Dietrich and Wahl using the line broadening effect produced by Os(dipy)3 on the nmr spectrum of Os(dipy)3 have been able to propose a value of > 5x 10" l.mole . sec at 6 °C in D2O (0.14 M [Cr] and 5x10 M [D- ]). 

Potassium perchlorate is made by converting sodium chlorate into sodium perchlorate in steel electrolytic cells that have platinum anodes and operate at a temperature of 65°C. Filtered potassium chloride solution is added to the sodium perchlorate, precipitating potassium perchlorate crystals, which are centrifuged, washed, and dried. The mother liquor now contains sodium chloride, which can be used as a cell feed for sodium chlorate manufacture. 

Aliquots of fission product solution with added known amounts of cesium and strontium were passed through a column of Amberlite IRA-400 (OH) and eluted with several column volumes of water. The strontium and cesium in the eluate were separated from each other by the oxalate and perchlorate precipitation method. By this means, the determinations of these two elements were accomplished rapidly and with good precision. By using an anion exchange column in the carbonate form, only cesium in fission products can be eluted (186,271). This type of separation should have. application to rapid procedures. ... 

Special attention is to be paid to alkali metals. Their reduction potentials are very negative (above -2V vs. SCE) and the electrolyte components must be reducible at very high negative potentials. The tetra-alkylammonium bases or salts are very convenient for such purposes these must be pure. The small variability of the half-wave potential of the reduction of sodium, potassium, rubidium and caesium ions makes impossible their polarographic discrimination. The half-wave potential of lithium is about 200 mV more negative than that of sodium or potassium and therefore it can be determined in the presence of up to a 10-fold excess of sodium or potassium. Some methods for separate determination of sodium and potassium have been described [17]. This procedure is based on the preliminary separation of the potassium by the perchlorate precipitation. 

In HPLC, alcohols and especially acetonitrile are often added to the sample to remove serum proteins. In CE, in addition to removing proteins, the presence of acetonitrile in the sample leads to stacking and indirectly improves precision of quantification because of the ability to increase the sample volume. We have analyzed several drugs and other natural compounds by CE after acetonitrile deproteinization. Protein removal can also be accomplished by alcohols such as ethanol and by acids such as perchloric. Precipitation with acids is less desirable in CE than with organic solvents because it increases the salt load. Following precipitation, proteins could also be dissolved in the appropriate buffers and assayed by CE. 

Nielsen, A. (1961) Diffusional controlled growth of a moving sphere. The kinetics of crystal growth in potassium perchlorate precipitation. The Journal of Physical Chemistry, 65, 46-49. 

When the electrolysis is finished, calculate the number of coulombs passed and the theoretical maximum yield of perchlorate in moles. Measure out an equal number of moles of potassium choride, in the form of a saturated (4M) solution, and stir this into the warm electrolyte. A fine perchlorate precipitate appears. Cool in ice and filter the potassium perchlorate on a small Buchner funnel. Wash with a little ice-cold water and suck as dry as possible then dissolve the crude product (which contains some chlorate) in 150 ml of hot water and recrystallize, cooling to below 10° before filtering off the crystals. Wash the crystals wdth about 50 ml of ice-cold 50 per cent alcohol, suck dry, and dry in air. The yield of recrystallized salt, based on the current consumption, is about 60 per cent. 

Copper(II) perchlorate was prepared by reaction of the carbonate with warm aqueous HCIO. The resultant solution was filtered and cooled the metal perchlorate precipitated was collected and recrystallized twice from water. The titre of the copper perchlorate solutions was determined using EDTA ( ). 

Perchloric hoods are usually constructed with an integral liner of a single piece of stainless steel, such as 316 stainless, which will resist the effects of the acid, although P VC can also be used as a liner. The liner should have coved comers and as few seams as possible to allow ease of decontamination. In order to avoid buildup of perchloric precipitates in the hood and duct system, a hood intended to be used for perchloric acid work must he equipped with a rinse system which will make it possible to thoroughly flush the interior of the hood and duct work with water. This may be done with a manual control system or by an automatic system that will come on and rinse the system for 20 - 30 minutes at the end of a work session. A combination of an automatic system which can be bypassed for additional rinses is preferable so the researcher may choose to clean the system if necessary. 

Potassium fluoride (12 g, 0.316 mol) is dissolved in 100 mL of doubly distilled water. Of this solution, 30 mL is combined with 10 mL of the LOOM silver perchlorate stock solution, and potassium perchlorate precipitates. The precipitate is separated by filtration through a small sintered crucible and washed repeatedly with the rest of the KF solution until the total volume equals 100 mL. The same electrolysis cell as for the preparation of Ag20j (part A) is used. The cell is filled with the silver fluoride solution and subsequently cooled to —2° (cf. part A). During electrolysis the current is raised from 10 to 40 mA within 120 min in a linear sweep or in five steps at minimum. Then the current is kept constant at 40 mA for another 120 min. The total charge transferred is 130 mA h thus, 80% of the Ag" cations will have been exchanged by protons. Typical yields are 380 mg per charge. 

Potassium fluoride (6 g, 0.158 mol) is dissolved in 100 mL of doubly distilled water. Of this solution, 30 mL is combined with 10 mL of the LOOM silver perchlorate stock solution, and potassium perchlorate precipitates. The precipitate is separated by filtration through a small sintered crucible and washed repeatedly with the rest of the KF solution until the total volume equals 100 mL. Adding 200 mL doubly distilled water gives the electrolyte to be used for the preparation of AgO. 

Taking francium as an example, it was assumed that the minute traces of francium ion Fr could be separated from other ions in solution by co-precipitation with insoluble caesium chlorate (VII) (perchlorate) because francium lies next to caesium in Group lA. This assumption proved to be correct and francium was separated by this method. Similarly, separation of astatine as the astatide ion At was achieved by co-precipitation on silver iodide because silver astatide AgAt was also expected to be insoluble. 

Add 0-1 ml. of concentrated sulphuric acid or of 72 per cent, perchloric acid cautiously to a cold solution of 0 01 mol (or 1 0 g.) of the quinone in 3-5 ml. of acetic anhydride. Do not permit the temperature to rise above 50°. AUow to stand for 15-30 minutes and pour into 15 ml, of water. Collect the precipitated sohd and recrystaUise it from alcohol. 

Solid Compounds. The tripositive actinide ions resemble tripositive lanthanide ions in their precipitation reactions (13,14,17,20,22). Tetrapositive actinide ions are similar in this respect to Ce . Thus the duorides and oxalates are insoluble in acid solution, and the nitrates, sulfates, perchlorates, and sulfides are all soluble. The tetrapositive actinide ions form insoluble iodates and various substituted arsenates even in rather strongly acid solution. The MO2 actinide ions can be precipitated as the potassium salt from strong carbonate solutions. In solutions containing a high concentration of sodium and acetate ions, the actinide ions form the insoluble crystalline salt NaM02(02CCH2)3. The hydroxides of all four ionic types are insoluble ... 

Carbonate is measured by evolution of carbon dioxide on treating the sample with sulfuric acid. The gas train should iaclude a silver acetate absorber to remove hydrogen sulfide, a magnesium perchlorate drying unit, and a CO2-absorption bulb. Sulfide is determined by distilling hydrogen sulfide from an acidified slurry of the sample iato an ammoniacal cadmium chloride solution, and titrating the precipitated cadmium sulfide iodimetrically. 

The precipitated acetyHde must be decomposed with hydrochloric acid after the titration as a safety measure. Concentrated solutions of silver nitrate or silver perchlorate form soluble complexes of silver acetyHde (89). Ammonia and hydrogen sulfide interfere with the silver nitrate method which is less... 

The chlorides, bromides, nitrates, bromates, and perchlorate salts ate soluble in water and, when the aqueous solutions evaporate, precipitate as hydrated crystalline salts. The acetates, iodates, and iodides ate somewhat less soluble. The sulfates ate sparingly soluble and ate unique in that they have a negative solubitity trend with increasing temperature. The oxides, sulfides, fluorides, carbonates, oxalates, and phosphates ate insoluble in water. The oxalate, which is important in the recovery of lanthanides from solutions, can be calcined directly to the oxide. This procedure is used both in analytical and industrial apptications. 

Ammonia, hydrochloric acid, and sodium perchlorate are mixed and the reaction mixture crystallised in a vacuum-cooled crystalliser. Ammonium perchlorate crystals are centrifuged, reslurried, recentrifuged, and then dried and blended for shipment. Mother Hquor is evaporated to precipitate sodium chloride and the depleted mother Hquor is recycled to the reactor. The AP product made by this method is 99% pure and meets the specifications for propeUant-grade ammonium perchlorate. The impurities are ammonium chloride, sodium perchlorate, ammonium chlorate, and water insolubles. 

The quaHtative determination of water-soluble perchlorates by precipitation using methylene blue yields a violet precipitate (105). Using potassium, mbidium, or cesium salts for precipitation from ethanol—water solutions can serve as a quaHtative determination of perchlorates (106). 

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

The mixture of diastereomers has been separated into its two principal components by Izatt, Haymore, Bradshaw and Christensen who had previously identified the two principal diastereomers as the cis-syn-cis and cis-anti-cis isomers. Their previous separation technique involved a protracted chromatography on alumina but the new method relied upon the difference in water solubility between the lead perchlorate and hydroniur perchlorate complexes. The lead perchlorate complex is essentially insoluble in aqueous solution and precipitates from it. Using this method, one may obtain 39% of the high-melting polymorph (mp 83—84°) and 44% of the low-melting compound (mp 62—63°). Note that the former also exists in a second crystalline form, mp 69—70°. 

Ammodendrine, C jH oONj, HjO (No. 1, table, p. 116). The base has m.p. 73 °, becomes anhydrous at 70-80°, and then melts at 50-60°, Wd i 0°. The salts are amorphous and deliquescent except the hydriodide B. HI, which forms a crystalline precipitate, m.p. 218-20°, from alcohol, and the perchlorate, m.p. 199-200°. An amorphous A-benzoyl derivative was obtained. With methyl iodide ammodendrine behaves as a secondary base, yielding first A-methylammodendrine hydriodide (a crystalline precipitate, m.p. 183-5°, from a mixture of alcohol and acetone), and at the second stage iV-methylammodendrine methiodide, m.p. 163-5°. On hydrogenation ammodendrine furnishes a dihydro-base, which is hydrolysed into acetic acid and 2 3 -dipiperidyl, C oHjoNj, and must be dZ-A-acetyl-3-a-piperidylpiperidine. Ammodendrine should therefore be acetyltetrahydroanabasine and is of biological interest as the first recorded occurrence of this type of alkaloid in the Leguminoss. ... 

PAYTA BARK. From this material Hesse isolated two alkaloids paytamine, C2iH240N2, amorphous and distinguished from its associated base by not being precipitated from solution by potassium iodide, and paytine, C2iH240N2. H2O. The latter crystallises from alcohol, has m.p. 156°, [a]o — 149-5°, and yields a crystalline hydrochloride, B. HCl, prisms from hot water with perchloric acid it gives a magenta red colour. 

Bromo-A-homo-estra-4y5 0)-diene-3, l-dione (49). A solution of silver perchlorate (0.55 g, 5 mole-eq) in acetone (2 ml) is added to a refluxing solution of monoadduct (48 0.28 g) in acetone (30 ml) containing water (0.5 ml). After being heated at reflux for 25 min the reaction mixture is cooled and the precipitated silver bromide is removed by filtration, yield about 0.11 g. The filtrate is diluted with water (500 ml) and is thoroughly extracted with chloroform. The chloroform extracts are washed with water and saturated salt solution, dried over anhydrous magnesium sulfate, and evaporated at... 

A-Homo-estra-, 4, )-triene-3, l-dione (50). A solution of bromo ketone (49 0.2 g), silver perchlorate (0.5 g) and 20% aqueous acetone (30 ml) is heated at reflux with stirring for 30 min and then allowed to cool to room temperature. The mixture is filtered to remove precipitated silver bromide (ca. 0.19 g) and the filtrate is diluted with water (200 ml) and then extracted with chloroform. The chloroform extracts are washed, successively with water, 5% sodium bicarbonate solution, water and saturated salt solution. After being dried over anhydrous magnesium sulfate, the solvents are removed at reduced pressure to give a solid. Recrystallization from ethyl acetate gives A-homo-estra-l,4,5(10)-triene-3,17-dione (50 0.17 g) mp 193-197°. 

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