Separation oxalates

Los Alamos is processing a wide variety of residues, including Pu-Be neutron sources, polystyrene-Pu02-U02 blocks, incinerator ash, Pu-U alloys and oxides, Pu-Zr alloys and oxides, Pu-Np alloys and oxides, Pu-Th alloys and oxides, etc. Processes have been developed for these scrap items (see Figure 2), but we need to know more about Pu-Np separations Pu-Th separations oxalate precipitations for both plus 3 and plus 4 valences valence stabilization dissolution methods for high-fired impure oxides in-line alpha monitors to measure extremely low concentrations of Pu and Am in HNO3 solutions and solubility of various mixtures of Pu02 and UO2 under a variety of conditions. 

A PRP -1 (Hamilton Reno, NV) reversed phase column was coated with cetylpyridinium and eluted with tetramethylammonium salicylate acetoni-trile water.89 The separation was comparable to that observed on conventional ion exchange. Coated phases were also used to separate oxalate complexes of manganese, cobalt, copper, and zinc.90 Reversed phase silica supports were coated with poly(N-ethyl-4-vinylpyridinium bromide), poly(dimethydiallylammonium chloride), poly(hexamethyleneguanidinium... 

SCX column was used to separate oxalate and urate.140 In this separation, differential pulse and DC amperometric detection were compared. Differential pulse detection was found to allow better selectivity in detection. Anion exchange on Diaion CA08 was used to separate 20 carboxylic acids in the analysis of white wine, as shown in Figure 10.141 Because many carboxylic acids have a relatively weak absorbance, detection is difficult. The colorimetric detection scheme shown in the figure may be useful in some applications. 

Sulphuric add test. To 0-5 g. of oxalic acid or of an oxalate, add I ml. of cone. H2SO4 and warm CO and COg are evolved (cf. formic acid). The CO burns with a blue flame. Detect the COg by passing the mixed gases evolved into lime-water. It is essential to test for the COj in a separate reaction, or (if the same test-tube is used) before testing for CO. 

Ethyl oxalate is the only liquid ester which gives this rapid separation of the amide, which is therefore characteristic. Methyl and ethyl formate react rapidly with ammonia, but the soluble formamide does not separate methyl succinate gives crystalline succinamide after about I hour s standing, other esters only after a much longer time. The solid esters, other than methyl oxalate, are either soluble in water and remain so when treated with ammonia, or alternatively are insoluble in water and hence clearly not methyl oxalate. 

The above example serves to iUustrate the basis of the procedure employed for the characterisation of aUphatic esters, viz., hydrolysis to, and identification of, the parent acids and alcohols. Most esters are liquids a notable exception is dimethyl oxalate, m.p. 54°. Many have pleasant, often fruit-hke, odours. Many dry esters react with sodium, but less readily than do alcohols hydrogen is evolved particularly on warming, and a sohd sodio derivative may separate on coohng (e.j/., ethyl acetate yields ethyl sodioacetoacetate ethyl adipate gives ethyl sodio cj/cZopentanone carboxylate). 

Urea oxalate is also sparingly soluble in amyl alcohol and since urea is soluble in this alcohol, the property may be utilised in separating urea from mixtures. An aqueous extract of the mixture is rendered slightly alkaline with sodium hydroxide solution and extracted with ether this removes all the basic components, but not urea. The residual aqueous solution is extracted with amyl alcohol (to remove the urea) upon adding this extract to a solution of oxalic acid in amyl alcohol crystalline urea oxalate is precipitated. 

Uses of oxalic acid ia each region are summarized in Table 5 (58). The demand for agrochemical/pharmaceutical production and for separation/recovery of rare-earth elements in each region has been increasing. The use for marble polishing in western Europe is unique to the region. 

Separation and Recovery of Rare-Earth Elements. Because rare-earth oxalates have low solubihty in acidic solutions, oxaUc acid is used for the separation and recovery of rare-earth elements (65). For the decomposition of rare-earth phosphate ores, such as mona ite and xenotime, a wet process using sulfuric acid has been widely employed. There is also a calcination process using alkaLine-earth compounds as a decomposition aid (66). In either process, rare-earth elements are recovered by the precipitation of oxalates, which are then converted to the corresponding oxides. 

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 pH effect in chelation is utilized to Hberate metals from thein chelates that have participated in another stage of a process, so that the metal or chelant or both can be separately recovered. Hydrogen ion at low pH displaces copper, eg, which is recovered from the acid bath by electrolysis while the hydrogen form of the chelant is recycled (43). Precipitation of the displaced metal by anions such as oxalate as the pH is lowered (Fig. 4) is utilized in separations of rare earths. Metals can also be displaced as insoluble salts or hydroxides in high pH domains where the pM that can be maintained by the chelate is less than that allowed by the insoluble species (Fig. 3). 

Morpholine [110-91-8] M 87.1, f -4.9", b 128.9", d 1.0007, n 1.4540, n 5 1.4533, pK 8.33. Dried with KOH, fractionally distd, then refluxed with Na, and again fractionally distd. Dermer and Dermer [J Am Ghent Soc 59 1148 1937] ppted as the oxalate by adding slowly to slightly more than 1 molar equivalent of oxalic acid in EtOH. The ppte was filtered and recrystd twice from 60% EtOH. Addition of the oxalate to cone aq NaOH regenerated the base, which was separated and dried with solid KOH, then sodium, before being fractionally distd. 

The alkaloid may be separated from accompanying hyoscyamine by extracting most of it with ether and then crystallising the mixed oxalates from water, that of norhyoscyamine separating first. It crystallises in colourless prisms, m.p. 140°, [a]j, — 23-0° (50 per cent. EtOH), is soluble in alcohol or chloroform, less so in ether or acetone, and sparingly in water... 

Papaverine, C20H21O4N. This alkaloid, first obtained by Merck, occurs in the mixture precipitated by ammonia from the mother liquors of opium extract from which morphine and codeine have been separated in Gregory s process, and methods for its isolation from this mixture have been published by Hesse and others. The alkaloid may be purified by conversion into the acid oxalate, B. H2C2O4, m.p. 196° or 201-5-202°, which is nearly insoluble in alcohol. 

Preparation. The mother liquors from strychnine manufacture are concentrated and the alkaloids precipitated as neutral oxalates. The precipitate is dried and extracted with dry alcohol in which the strychnine salt is the more soluble. The less soluble salt dissolved in water is decolorised with charcoal, the alkaloid regenerated with ammonia and purified by crystallisation as the sulphate. According to Saunders, pure brucine may be obtained by slow crystallisation from a solution of the pure hydrochloride in alcoholic ammonia. A method of separation depending on the greater solubility in water of strychnine hydriodide was employed by Shenstone, whilst others have made use of the sparing solubility of strychnine chromate for the removal of small quantities of this alkaloid from brucine. For a large scale process see Schwyzer. ... 

B. H2SO4.6HgO, crystallises with difficulty in prismatic rods, m.p.>310°, Wd + 52-94° (HgO) the oxalate, B. HgCg04, separates from alcohol in colourless leaflets, m.p. 235° dec.), [a]n + 55-6° (HgO). The base gives a pink colour, changing to bluish-violet with vanillin and hydrochloric acid, and a brown, changing through purple to blue with sulphuric acid. 

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