Tartaric acid, Table

Crisp, Merson Wilson (1980) found that the addition of metal fluorides to formulations had the effect of accelerating cement formation and increasing the strength of set cements the effect was enhanced by the presence of (-I-)-tartaric acid (Table 5.13). Strength of cements formed from an SiOj-AljOg-Cag (P04)2 glass, G-247, can be almost doubled by this technique. 

In Tables I-III we present RHF and MP2 relative energies as well as selected geometrical parameters of the conformers of (R,R)-tartaric acid diamide (Table I), (R,R)-tartaric acid (Table II), and (R,R)-tartaric acid N,N.N N -tetramethyl diamide (Table III). Each of the conformers of these molecules has been designated by a set of 5 characters. 

Enantiomers have identical physical and chemical properties in achiral environments. The enantiomers of tartaric acid (Table 6.1), for example, have the same melting point, the same boiling point, the same solubilities in water and other common solvents, and the same values of pif (the acid ionization constant), and they all undergo the same acid-base reactions. The enantiomers of tartaric acid do, however, differ in optical activity (the ability to rotate the plane of polarized light), a property that is discussed in the next section. 

An equimolar mixture of two enantiomers is called a racemic mixture, a term derived from the name racemic acid (Latin racemus, a cluster of grapes), originally given to an equimolar mixture of the enantiomers of tartaric acid (Table 6.1). Because a racemic mixture contains equal numbers of the dextrorotatory and the levorotatory molecules, its specific rotation is zero. Alternatively, we say that a racemic mixture is optically inactive. A racemic mixture is indicated by adding the prefix ( + ) to the name of the compound. 

Physical Properties. When crystaUized from aqueous solutions above 5°C, natural (R-R, R )-tartaric acid is obtained in the anhydrous form. Below 5°C, tartaric acid forms a monohydrate which is unstable at room temperature. The optical rotation of an aqueous solution varies with concentration. It is stable in air and racemizes with great ease on heating. Some of the physical properties of (R-R, R )-tartaric acid are Hsted in Table 7. 

Some physical properties of the four enantiomeric tartaric acids are compared in Table 8. 

In common with other hydroxy organic acids, tartaric acid complexes many metal ions. Formation constants for tartaric acid chelates with various metal ions are as follows Ca, 2.9 Cu, 3.2 Mg, 1.4 and Zn, 2.7 (68). In aqueous solution, tartaric acid can be mildly corrosive toward carbon steels, but under normal conditions it is noncorrosive to stainless steels (Table 9) (27). 

Economic Aspects. The estimated total worldwide market for tartaric acid is 58,000 t and potassium bitartrate (acid basis) is 20,000 t. The majority of tartaric acid consumption, represented by beverage, food, and pharmaceutical appHcations, is shown in Table 10. Potassium bitartrate (cream of tartar) is primarily used in baking powders and mixes. 

Table 10. 1991 Worldwide Tartaric Acid Market Segments ...

Specifications and Analysis. (R-R, R )-Tartaric acid sold in the United States meets the specifications of the Food Chemicals Codex (40) and the tdationalFormulary (41) (Table 12). 

Acidulants. Acidulants give the beverage a tart or sour flavor, adjust pH to faciUtate the function of ben2oate as a preservative, reduce microbiological susceptibiUty, and act as a catalyst for the hydrolytic inversion process in sucrose sweetened beverages. The primary carbonated beverage acidulants are phosphoric acid [7664-38-2] and citric acid [77-92-9]. Other acidulants include ascorbic, tartaric, malic, and adipic acid (Table 2). 

A large number of chiral crowns have been prepared by numerous groups. The reader is directed to the tables at the end of this chapter to obtain an overview of these structures. It would not be useful to try to recount the synthetic approaches used in the preparation of all of these compounds we have chosen rather to subdivide this mass of compounds into three principal groups. The groups are (1) Cram s chiral binaphthyl systems (2) chiral crowns based on the tartaric acid unit and (3) crowns incorporating sugar subunits. These are discussed in turn, below. 

The enantioselectivity a is defined as the distribution ratio of one single enantiomer over the two chiral phases and has been determined experimentally for a variety of compounds (Table 5-1). It has been known from work by Prelog [66, 67] that tartaric acid derivatives show selectivities towards a-hydroxyamines and amino acids. However, from Table 5-1 it is obvious that tartaric acid derivatives show selectivity for many other compounds, including various amino bases (e.g. mirtazapine (10)) and acids (e.g. ibuprofen (11)). The use of other chiral selectors (e.g. PLA)... 

Some physical properties of the three stereoisomers are listed in Table 9.3. The (+)- and (-j-tartaric acids have identical melting points, solubilities, and densities but differ in the sign of their rotation of plane-polarized light. The meso isomer, by contrast, is diastereomeric with the (+) and (-) forms. As such, it has no mirror-image relationship to (+)- and (-)-tartaric acids, is a different compound altogether, and has different physical properties. 

Table 9,3 Some Properties of the Stereoisomers of Tartaric Acid...

Table sugar, sec Sucrose Tagatose, structure of, 975 Talose. configuration of, 982 Tamiflu, molecular model of, 130 Tamoxifen, synthesis of, 744 Till] DNA polymerase, PCR and, 1117 Tartaric acid, stereoisomers of, 305-306... 

Advances in analytical procedures resulted in several reports on anthocyanins acy-lated with hydroxycinnamic acids (p-coumaric, caffeic, ferulic, sinapic, and 3,5-dihydroxycinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic and gallic acids), and aliphatic acids (malonic, acetic, malic, oxalic, succinic and tartaric acids). However, not all of them were found in anthocyanins isolated from foods. Among the 44 fruits listed in Table 4.3.1, 15 presented acylated anthocyanins as did 12 of 13 vegetables shown in Table 4.3.3 and 2 of the 9 grains cited in Table 4.3.4. On the other hand, acylated anthocyanins were found in all grapes from Vitis species, although at different abundance levels, as can be seen in Table 4.3.2. A higher... 

Table 5.11. Effect of +)-tartaric acid on glass polyalkenoate cement properties...

Table 5.12. Ejfect of the various tartaric acids on glass polyalkenoate cement properties Crisp, Lewis Wilson, 1979)...

Chiral modifiers were screened in the zinc chemistry. Once again, in the case of aniline ketone 36, chichona alkaloids, binaphthol, and tartaric acid derivatives gave very poor selectivity and ephedrine derivatives provided good selectivity. The results are summarized in Table 1.8. 

This redox couple has been studied in H2S04 and tartaric acid at the dropping mercury interface by Delahay et al.u They only reported the value of a for the reaction. This system is only stable when the concentration of Ti3+ is 10 to 20 times higher than that of Ti4+. The AE / V versus w l/2 plots for this reaction in 1.0 N HC1 are shown in Fig. 10 and the kinetic parameters60 are given in Table 3. The value of a is 0.49 and k°a = 5.56 x 10 4cm/s. The reaction appears to be irreversible. 

By this process phenylglycine derivatives have been resolved by crystallization of the tartaric acid ammonium salts. The equilibration is induced at the amino ester stage by forming the configurationally labile imines with a catalytic amount of benzaldehyde or acetone (Table 11). 

Table 12 shows the chemical shift for the CH-CH part of selected (/ ,/ )-tartaric acid monoesters of amino alcohols, mainly well-known /1-blockers. As can be easily seen, the chemical shifts of the (R)- and (S)-amino alcohol derivatives lie within a narrow range, dependent on the kind of tartaric acid used. Monoesters of a-amino (/f)-alcohols with (R,R)-0,0-diacetyl- or... 

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