Separators perchlorate

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. 

Fig. 2. Distribution of REE ia the HDEHP—perchlorate system. The lanthanide—yttrium separation factor, E(Ln/Y), is plotted as a function of lanthanide...

Because of the use of ammonium perchlorate as a soHd oxidizer for rocket propeUants, the thermal decomposition has been much studied (29—32). Three separate activation energies have been observed for AP decompositions an activation energy of 123.8 kJ/mol (29.6 kcal/mol) is found below 240°C of 79.1 kj/mol (18.9 kcal/mol) above 240°C and finally, of 307.1 kj/mol (73.4 kcal/mol) between 400—440°C (33,34). Below 300°C, the equation... 

Highly pure perchloric acid can also be produced by a patented electrochemical process ia which 22% by weight hypochlorous acid is oxidized to chloric acid ia a membrane-separated electrolyzer, and then additionally oxidized to perchloric acid (8,84). The desired electrochemical oxidation takes place ia two stages ... 

The anode and cathode chambers are separated by a cation-permeable fluoropolymer-based membrane (see Membrane technology). Platinum-electroplated high surface area electrodes sold under the trade name of TySAR (Olin) (85,86) were used as the anode the cathode was formed from a two-layer HasteUoy (Cabot Corp.) C-22-mesh stmcture having a fine outer 60-mesh stmcture supported on a coarse inner mesh layer welded to a backplate. The cell voltage was 3.3 V at 8 kA/m, resulting ia a 40% current efficiency. The steady-state perchloric acid concentration was about 21% by weight. 

A practical method for low level perchlorate analysis employs ion chromatography. The unsuppressed method using a conductivity detector has a lower detectable limit of about 10 ppm. A suppression technique, which suppresses the conductivity of the electrolyte but not the separated ions, can further improve sensitivity (110,111). Additionally, ion chromatography can be coupled with indirect photometric detection and appHed to the analysis of perchlorates (112). 

Oxo Ion Salts. Salts of 0x0 anions, such as nitrate, sulfate, perchlorate, iodate, hydroxide, carbonate, phosphate, oxalate, etc, are important for the separation and reprocessing of uranium, hydroxide, carbonate, and phosphate ions are important for the chemical behavior of uranium ia the environment (150—153). 

The products of equation 11 are separated by controlled crystalLi2ations to produce high purity crystalline anhydrous ammonium perchlorate and sodium chloride. The main use for ammonium perchlorate is as an oxidi2er in the propellant of rockets and missiles (see Explosives and propellants). 

Acetylcholine chloride [60-31-1] M 181.7, m 148-150 , 151". It is very sol in H2O (> 10%), and is very hygroscopic. If pasty, dry in a vacuum desiccator over H2SO4 undl a solid residue is obtained. Dissolve in abs EtOH, filter and add dry Et20 and the hydrochloride separates. Collect by filtration and store under very dry conditions. [J Am Chem Soc 52 310 1930.] The chloroplatinate crystallises from hot H2O in yellow needles and can be recrystd from 50% EtOH, m 242-244° [Biochem J 23 1069 7929], other m given is 256-257°. The perchlorate crystallises from EtOH as prisms m 116-117°. [J Am Pharm Assocn 36 272 1947.]... 

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°. 

The materials of construction, from the cupboard to the fan, should be inorganic and resistant to attack by perchloric acid. For the cupboard itself suitable materials include stainless steel of types, 316 or 317, solid epoxy resin, and rigid PVC. Stainless steel has been popular for this application as it is easy to form, weld, and polish. It is, however, attacked by the acid, which causes discoloration of the metal surface and the formation of iron(III) perchlorate, which can be explosive. Ductwork, separate from other extract systems, is usually made from stainless steel or plastic materials. Fire regulations may preclude the use of plastic ductwork or require it to be sheathed in an outer casing of metal or GRP. The fan casing and impeller can both be made of plastic. 

The saturated amine (88) was separated from the enamine (87) by basic hydrolysis, which resulted in the hydrolysis of the enamine. The perchlorate salt of the enamine (89) showed a strong absorption in the infrared at 1680 (characteristic of... 

Iminium salts are readily available from C protonation of the corresponding enamines (7). Experimentally the procedure is very simple The enamine dissolved in ether or some other solvent is treated with an appropriate acid such as anhydrous hydrogen chloride or 70% perchloric acid. The iminium salt usually separates and is then collected. Protonation at low temperatures... 

Lukes studied the reaction of N-methyl lactams with Grignard reagents. With the five- (39-42) and six-membered (43-47) rings, 2,2-dialkylated bases (16, = 1,2) are formed as by-products in addition to the l-methyl-2-alkyl pyrrolines (15, = 1) or l-methyl-2-alkyl piperideines (15, =2). Aromatic Grignard reagents afford only the unsaturated bases, probably because of steric factors (48,49). Separation of enamines and 2,2-dialkylated amines from each other can be easily achieved since the perchlorates of the enamines and the picrates of 2,2-dialkylated bases crystallize readily. Therefore enamines can be isolated as crystalline perchlorates and the 2,2-dialkylated bases as crystalline picrates. Some authors who repeated the reactions isolated only pyrrolines (50,57) or, by contrast, 2,2-dialkylated bases (52). This can be explained by use of unsuitable isolation techniques by the authors. 

The oxide (p. 1209), chalcogenides (p. 1210) and halides (p. 1211) have already been described. Of them, the only ionic compound is HgF2 but other compounds in which there is appreciable charge separation are the hydrated salts of strong oxoacids, e.g. the nitrate, perchlorate, and sulfate. In aqueous solution such salts are extensively hydrolysed (HgO is only very weakly basic) and they require acidification to prevent the formation of polynuclear hydroxo-bridged species or the precipitation of basic salts such as Hg(OH)(N03) which contains infinite zigzag chains ... 

To a suspension of 500 mg of 160i,17a-dihydroxyprogesterone in 25 ml of freshly redistilled acetophenone isadded 0.125 ml of 72% perchloric acid and the mixture isagitated at room temperature for one hour. The clear solution is washed with dilute sodium bicarbonate to remove excess acid and the acetophenone layer, after addition of chloroform is separated from the aqueous phase. The organic layer is dried over sodium sulfate and after removal of the chloroform and acetophenone in high vacuum the residue is crystallized from 95% alcohol. The pure acetophenone derivative has a melting point of about 142° to 144. ... 

To a solution of 2.4 g of pregna-1,4,9(11)-triene-21-ol-3,20-dione-[17o ,16a-d] -2 -methylox-azoline 21 -acetate in 24 ml of tetrahydrofuran, 12.8 ml of 0.46N perchloric acid are added at 15°C under stirring. N-bromoacetamide (1.1 g) is then added to the mixture which is kept far from light, and stirred for 4 hours at room temperature. After lowering the temperature to 10°C, a saturated solution of sodium bisulfite is added in order to decolorize the mixture, which is then poured into 120 ml of Ice water. A product separates, which is collected by filtration, washed with water and then dried, thus obtaining 2.81 g of crude 9a-bromo-pregna-... 

Finally, the data in Table 8-6 show the elution of the lead column. The eluent is H,0. The driving force for the elution in this case is the lack of C10 present to act as an anion in the binding of the ammonium perchlorate salt pair. The D-enantiomer versus L-enantiomer ratio in the elution is slightly greater than 6 1, as expected by the inherent selectivity of the ligand. For this separation system, LiClO is then added back to the eluent and the eluent is sent on as load to the next purification stage. 

A fluid-bed reactor is used at moderate pressures at approximately 450°C. The reactor effluent, containing chlorinated organics, water, a small amount of HCl, carbon dioxide, and other impurities, is condensed in a water-cooled graphite exchanger, cooled in a refrigerated condenser, and then scrubbed. Separation of perchlor from the trichlor occurs by successive distillation. Figure 7-6 shows the PPG process. 

Figure 7-6. The PPG Industries Inc. Chloroethylene process for producing perchloro- and trichloroethylene (1) reactor, (2) graphite exchanger, (3) refrigerated condenser, (4) scrubber, (5) phase separation of perchlor from trichlor, (6, 7) azeotropic distillation, (8) distillation train, (9-11) crude trichlor separation—purification, (10-16) crude perchlor separation—purification.

Interfering cations, except aluminium and zirconium, can be removed by passage through an ion exchange column. In the presence of interfering anions and also aluminium and zirconium, fluoride may be separated as hydrofluorosilicic acid by distilling with dilute perchloric acid at 135 °C (temperature maintained by the addition of water) in the presence of a few glass beads. 

H- and 3//-Azepines are generally unstable in aqueous acid solution and the few examples of simple azepinium salts, namely perchlorates,77 bromides,105 picrates35201 and a solitary iodide,105 have been prepared under nonaqueous conditions. The fractional crystallization of oxalate salts has been used for the separation of mixtures of 4- and 6-substituted 3f/-azepines,66 and 3,6-di-tm-butyl- and 2,5-di-tert-butyl-3//-azepine, on treatment with tetrafluoroboric acid in acetonitrile, are converted quantitatively into their crystalline tetrafluoroboratc salts.70... 

Since the early days of using PVC separators in stationary batteries, there has been a discussion about the generation of harmful substances caused by elevated temperatures or other catalytic influences, a release of chloride ions could occur which, oxidized to perchlorate ions, form soluble lead salts resulting in enhanced positive grid corrosion. Since this effect proceeds by self-acceleration, the surrounding conditions such as temperature and the proneness of alloys to corrosion as well as the quality of the PVC have to be taken carefully into account. 

A further kinetic investigation of the rates of cleavage of diphenylmercury (and some dialkylmercurials) showed similar kinetic features608. The first-order rate for the reaction of diphenylmercury with acetic acid at 25 °C was 4.98 x 10", which agreed quite well with the value from the above determination (2 x 10-4 at 42 °C with dioxan). In the presence of perchloric acid, second-order kinetics were found to be obeyed (for dineophyl mercury and presumably for diarylmercurials as well) for a twofold concentration change in both mercurial and perchloric acid. Two separate mechanisms were proposed for the reactions in the absence, and presence, of perchloric acid. Under the former conditions an SEi process (244) was... 

Speciation of plutonium leached from the glass cubes is shown in Figure 1. The first bar represents the total amount of insoluble plutonium and is the summation of suspended plutonium (the difference between the values for filtered and unfiltered waters) and sorbed plutonium—viz., the amount removed from the cubes by a 0.1 M perchloric acid wash, normalized to the volumes of leachant solutions so that it is comparable to the other values in the graphs. For simplicity, the insoluble fractions are combined in one bar, whereas the various oxidation states in the soluble fraction are represented by separate bars. It should be noted that the ordinate scale varies among the graphs. 

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