Sodium ammonium tartrates solubility

Resolution can be thought of as the converse of racemization (Section 2.4). One starts with a 50 50 mixture of both enantiomers and separates this mixture into the individual enantiomers. Of course, for some purposes one may only want one enantiomer, and recovery of the second enantiomer can be painstaking. Since enantiomers have identical properties, including solubility, separation of enantiomers by recrystallization is quite rare. It was, however, such a crystallization by Pasteur in 1848 that opened up the field of resolution. Pasteur s key observation was that two distinct but related types of crystal were obtained from an aqueous solution of the sodium ammonium salt of racemic tartaric acid. The two types of crystal were related as object and non-superimposable mirror image, and one type was identical to the dextrorotatory crystals of sodium ammonium tartrate obtained from (+)-tartaric acid, itself obtained as a by-product of wine-making. 

Enantiomers cannot be separated by the usual separation techniques such as fractional distillation or crystallization because their identical boiling points and solubilities cause them to distill or crystallize simultaneously. Louis Pasteur was the first to separate a pair of enantiomers successfully. While working with crystals of sodium ammonium tartrate, he noted that the crystals were not identical—some of the crystals were right-handed and some were left-handed. He painstakingly separated the two kinds of crystals with a pair of tweezers. He found that a solution of the right-handed crystals rotated the plane of polarized light clockwise, whereas a solution of the left-handed crystals rotated the plane of polarized light counterclockwise. 

Lead acetate White precipitate of lead sulfate soluble in hot concentrated sulfuric acid, ammonium acetate, ammonium tartrate, and sodium hydroxide... 

Lead acetate solution white precipitate of lead sulphate, PbS04, soluble in hot concentrated sulphuric acid, in solutions of ammonium acetate and of ammonium tartrate (see under Lead, Section III.4, reaction 5), and in sodium hydroxide solution. In the last case sodium tetrahydroxoplumbate(II) is formed, and on acidification with hydrochloric acid, the lead crystallizes out as the chloride. If any of the aqueous solutions of the precipitate are acidified with acetic acid and potassium chromate solution added, yellow lead chromate is precipitated (see under Lead, Section III.4, reaction 6). 

Scandium is usually present in rare earth minerals in small amounts (the rare mineral thortveitite containing 37 per cent SC2O3 is an exception). It collects in the soluble end of the bro-mate fractionations, but it is easily separated from the other soluble salts by the fact that it is the least basic of the whole group. Consequently, fractional precipitation or fusion of the nitrates concentrates the scandium rapidly. Scandium may also be precipitated from boiling acid solution by sodium silicofluoride its double ammonium tartrate and double potassium sulfate are also difficultly soluble. 

Similar relationships are met with in the case of sodium ammonium d- and Z-tartrate and sodium ammonium racemate but in this case the racemate is the stable form in contact with solution above the transition point (27 ). Below the transition point, therefore, the solubility curve of the mixed tartrates will lie below the solubility curve of the racemate. Below the transition point, therefore, sodium ammonium racemate will break up in contact with solution into a mixture of sodium ammonium d- and Z-tartrates. At a higher temperature, 35°, sodium ammonium racemate undergoes decomposition into sodium racemate and ammonium racemate. ... 

Saturated sodium hydrogen tartrate solution (NaH- C HnOf,) white precipitate of ammonium acid tartrate NH4 H C4H4O6, similar to but slightly more soluble than the corresponding potassium salt, from which it is distinguished by the evolution of ammonia gas on being heated with sodium hydroxide solution. 

On triturating the calcium tartrate with dilute sulphuric acid, gypsum was precipitated and on evaporating the filtrate to a syrup, crystals, which were tartaric acid, shot on cooling. By adding a solution of barilla (sodium carbonate), acid and neutral sodium tartrates were prepared from the acid. Ammonium tartrate crystals were prepared and distilled, and the formation of pyrotartaric acid and tartaric anhydride seems to have been detected. Cavendish found that a solution of calcium tartrate becomes turbid on heating, indicating a decrease of solubility with rise of temperature. 

Boron zirconimn chelates from ammonium hydroxide water-soluble amines sodium or potassimn zirconium and organic acid salts such as lactates, citrates, tartrates, glycolates, malates, gluconates, glycerates, and mandelates with polyols such as glycerol, erythritol, arabitol, xylitol, sorbitol, dulcitol, mannitol, inositol, monosaccharides, and disaccharides [463,464,1592,1593]... 

H. Stamm also measured the solubilities of the salts of the alkalies in liquid ammonia —potassium hydroxide, nitrate, sulphate, chromate, oxalate, perchlorate, persulphate, chloride, bromide, iodide, carbonate, and chlorate rubidium chloride, bromide, and sulphate esesium chloride, iodide, carbonate, and sulphate lithium chloride and sulphate sodium phosphate, phosphite, hypophosphite, fluoride, chloride, iodide, bromate, perchlorate, periodate, hyponitrire, nitrite, nitrate, azide, dithionate, chromate, carbonate, oxalate, benzoate, phtnalate, isophthalate ammonium, chloride, chlorate, bromide, iodide, perchlorate, sulphate, sulphite, chromate, molybdate, nitrate, dithionate, thiosulphate, persulphate, thiocyanate, phosphate, phosphite, hypophosphite, arsenate, arsenite, amidosulphonate, ferrocyanide, carbonate, benzoate, methionate, phenylacetate, picrate, salicylate, phenylpropionate, benzoldisulphonate, benzolsulphonate, phthalate, trimesmate, mellitate, aliphatic dicarboxylates, tartrate, fumarate, and maleinate and phenol. 

Calcium chloride solution no precipitate with neutral solutions in the cold (difference from tartrate), but on boiling for several minutes a crystalline precipitate of calcium citrate, Ca3(C6H507)2.4H20, is produced. If sodium hydroxide solution is added to the cold solution containing excess calcium chloride, there results an immediate precipitation of amorphous calcium citrate, insoluble in solutions of caustic alkalis, but soluble in ammonium chloride solution on boiling the ammonium chloride solution, crystalline calcium citrate is precipitated, which is now insoluble in ammonium chloride. 

Ammonia, ammonium sulphide or sodium hydroxide solution white precipitate of thorium hydroxide, Th(OH)4 or Th02.xH20, insoluble in excess of the reagent, but readily soluble in dilute acids when freshly precipitated. Tartrates and also citrates prevent the precipitation of the hydroxide. 

Ammonia or ammonium sulphide solution white precipitate of cerium(III) hydroxide, Ce(OH)3 (or Ce203.xH20), insoluble in excess of the precipitant, but readily soluble in acids. The precipitate slowly oxidizes in the air, finally becoming converted into yellow cerium(IV) hydroxide, Ce(OH)4 (or Ce02.xH20). Sodium hydroxide solution gives a similar result. The precipitation is prevented by tartrates and citrates. 

See American Patent, 1077462 Baiziss and Qavion, J. Amer. Ghem. Soe., 1921, 43. 583 Christiansen, ibid., 1922, 44, 2340 Fonmeau, Tr4 ouel, and B6noit, BuU. 80c. ehim., 1927, [iv.], 41, 499. Stable solutions of bismuth salts of this derivative or similar arylarsinic acids are prepared by the addition of a base such as piperazine, or sodium ctr ammonium hydromde, to a susmnsion of the salt, to render it soluble, and of a salt of an aliphatic hydroxypolybasio aciA such as potassium tartrate or citrate—British Patent, 277774 (1926) French Patent, 632834, See British Patent, 264797 (1926). 

The second important observation on stereoisomer separation also involved ammonium sodium tartrate. Thirty-four years after Pasteur s observation, Jungfleisch (1882) observed that carefully introducing crystals of the individual isomers into different areas of a supersaturated solution of ammonium sodium tartrate resulted in the growth of isomerically pure crystals. These two observations form the basis for most industrial scale crystallizations for the purification of enantiomers or diastereoi-somers. However, it is more common for a solute to crystallize with the thermodynamically stable crystal form being a compound of the two isomers. This is typically denoted as a racemic compound. Secor (1963) made the first systematic review of optical isomer separation by crystallization, based upon phase behavior. Collet, Brienne, and Jacques (1980) applied systematic thermodynamics to the phase behavior, and developed straightforward methods for correlating the solubilities of isomers. 

---