Barium extraction

Edelbeck L, West PW. 1970. Determination of trace concentrations of barium extracted from aqueous systems. Anal Chim Acta 52 447-453. 

Extract the acidified solution with ether, remove the ether and identify the phenol in the usual manner (see Section IV,114).f Add a few drops of bromine water or nitric acid to the aqueous layer and test for sulphate with barium chloride solution. 

Chemical precipitation and solvent extraction are the main methods of purifying wet-process acid, although other techniques such as crystallisa tion (8) and ion exchange (qv) have also been used. In the production of sodium phosphates, almost all wet-process acid impurities can be induced to precipitate as the acid is neutralized with sodium carbonate or sodium hydroxide. The main exception, sulfate, can be precipitated as calcium or barium sulfate. Most fluorine and siUca can be removed with the sulfate filter cake as sodium fluorosiUcate, Na2SiFg, by the addition of sodium ion and control of the Si/F ratio in the process. 

The fused product contains about 60—85% barium sulfide, unreacted barium sulfate, and impurities present in barite and ash. The soluble barium sulfide is extracted from the mixture with water and separated from the insoluble impurities by filtration. 

Aluminum nitrate nonahydrate is prepared by dissolving aluminum or aluminum hydroxide in dilute nitric acid, and crystaUi2ing the product from the resulting aqueous solution. It is made commercially from aluminous materials such as bauxite. Iron compounds may be extracted from the solution with naphthenic acids (21) before hydrate precipitation. In the laboratory it is prepared from aluminum sulfate and barium nitrate. 

Quantitatively, sulfur in a free or combined state is generally determined by oxidizing it to a soluble sulfate, by fusion with an alkaH carbonate if necessary, and precipitating it as insoluble barium sulfate. Oxidation can be effected with such agents as concentrated or fuming nitric acid, bromine, sodium peroxide, potassium nitrate, or potassium chlorate. Free sulfur is normally determined by solution in carbon disulfide, the latter being distilled from the extract. This method is not useful if the sample contains polymeric sulfur. 

The ester is hydrolysed by refluxing for l-2h with 1-5% of barium carbonate suspended in water or with aqueous sodium carbonate solution. The solution is cooled and extracted with diethyl ether, toluene or chloroform. It is then acidified and the acid is collected by filtration or extraction, and recrystallised or fractionally distilled. 

The process of isolation finally adopted by the former authors consists in precipitating as reineckates the water-soluble bases contained in a methyl alcoholic extract of the curare. The mixed reineckates are further purified, by solution in acetone and precipitation with water as often as may be necessary. The product so cleaned represents the bulk of the biological activity of the crude drug the mother liquors may contain curine (p. 374), which indicates a menisperm as one of the components of such curares. The mixed reineckates are then fractionated chromato-graphically over alumina and the components isolated as chlorides by the use of silver sulphate and barium chloride in succession. This process has been modified in detail by Schmid and Karrer, who have also found that with their curare, the more soluble reineckate fraction includes less potent quaternary alkaloids. 

In a 500-ml round-bottom flask fitted with a condenser, and a heating mantle is placed a mixture of 25 g of diethyl 5-(l -carboxy-2 -oxocyclohexyl)valerate, 70 g of barium hydroxide, and 200 ml of methanol, and the mixture is refluxed for 24 hours. After cooling, the mixture is acidified (pH 4) by cautious addition of cold 10% aqueous hydrochloric acid. The acidified solution is saturated with sodium chloride and then extracted three times with 100-ml portions of chloroform. The combined chloroform extracts are dried (anhydrous magnesium sulfate) and evaporated. On vacuum distillation, the residue affords the product (about 15 g), bp 176-17870.5 mm. 

Poloxamers are used primarily in aqueous solution and may be quantified in the aqueous phase by the use of compleximetric methods. However, a major limitation is that these techniques are essentially only capable of quantifying alkylene oxide groups and are by no means selective for poloxamers. The basis of these methods is the formation of a complex between a metal ion and the oxygen atoms that form the ether linkages. Reaction of this complex with an anion leads to the formation of a salt that, after precipitation or extraction, may be used for quantitation. A method reported to be rapid, simple, and consistently reproducible [18] involves a two-phase titration, which eliminates interferences from anionic surfactants. The poloxamer is complexed with potassium ions in an alkaline aqueous solution and extracted into dichloromethane as an ion pair with the titrant, tet-rakis (4-fluorophenyl) borate. The end point is defined by a color change resulting from the complexation of the indicator, Victoria Blue B, with excess titrant. The Wickbold [19] method, widely used to determine nonionic surfactants, has been applied to poloxamer type surfactants 120]. Essentially the method involves the formation in the presence of barium ions of a complex be-... 

The requirements of the US Armed Forces are contained in Mil Spec JAN-B-660, Barium Oxalate (For Use In Ammunition) , (5 Aug. 1948) Color — white moisture — 0.3% max material insol in 10% HC1 soln - 0.5% max material sol in water - 0.3% max water sol alkalinity — 0.1% max water sol acidity — the water extract shall not be acid to methyl orange barium oxalate — 92% min calcium salts —... 

Y. B. Zeng and S. B. Fu. The inhibiting property of phosphoric acid esters of rice bran extract for barium sulfate scaling. Oilfield Chem, 15(4) 333-335,365, December 1998. 

A waste is toxic under 40 CFR Part 261 if the extract from a sample of the waste exceeds specified limits for any one of eight elements and five pesticides (arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, endrin, methoxychlor, toxaphene, 2,4-D and 2,4,5-TP Silvex using extraction procedure (EP) toxicity test methods. Note that this narrow definition of toxicity relates to whether a waste is defined as hazardous for regulatory purposes in the context of this chapter, toxicity has a broader meaning because most deep-well-injected wastes have properties that can be toxic to living organisms. 

The quinoline can be recovered by neutralization of the aqueous solution, extraction of the quinoline into ether, and distillation of the dried (over barium oxide) ether extract. 

Turanose Phenylosotriazole. A solution of 15 g. of turanose phenylosazone in 300 cc. of hot water was placed on the steam-bath and a solution of 22 g. of copper siilfate pentahydrate in 150 cc. of hot water was added. The mixture turned a deep cherry-red at once and in a short time (fifteen min.) a red precipitate had formed and the solution had become green. After thirty minutes from the time of addition of the copper solution, the solution was cooled, filtered, and the copper removed as sulfide. The clear light yellow filtrate was neutralized with 45 g. of barium carbonate and the insoluble material removed by filtration. The filtrate was extracted with five 50-cc. portions of ether to remove the aniline, and the aqueous portion was concentrated in vacuo to a thick sirup. The sirup was dissolved in 60 cc. of warm alcohol, filtered to remove a slight turbidity and diluted with 65 cc. of ether. Upon cooling and scratching, the product crystallized as large prisms yield 8.9 g. (72%). The phenylosotriazole was recrystallized from 10 parts of alcohol and when pure showed the melting point 193-194° and rotated [a Jj" + 74.5° in aqueous solution (c, 0.90). 

In order to suppress interferences due to the presence of inorganic species and reliably determine the proteinaceous composition of the sample, a clean-up step has often been introduced in the analytical procedure. This step may include the extraction of the proteinaceous matter by an ammonia solution [8], the use of a cation-exchange resin [8,55], a chelating agent [9,41,44], the use of a Cig resin or the use of barium chloride solution to suppress sulfates [10,81,82]. Table 9.1 reports the methods used to overcome such problems. 

Barium Barium pre-concentrated on cation exchange resin, then extraction with nitric acid Graphite furnace AAS [78]... 

Early work was based on concentrating the radium from the seawater sample by adding barium and coprecipitating with barium sulfate. This concentration procedure has been replaced by one involving the extraction of radium from seawater on acrylic fibre coated with manganese dioxide [19,20] (Mn fibres). By use of this technique, volumes of 200-2000 litres may be sampled routinely. 

Measurements of 226radium are simpler than those for 228radium and are more precise. These measurements are generally made by concentrating the radium from up to a few litres via barium sulfate precipitation followed by thick source a counting or by 222radon extraction following dissolution of barium sulfate [21]. 

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