Stability constant lactate

The enthalpies and entropies of formation of mono-mandelato-complexes have been determined and, in comparison with other hydroxycarboxylic acid complexes, the enthalpy order of stabilization is lactate > a-hydroxyiso-butyrate mandelate > glycolate, whereas the entropy order of stabilization is glycolate > a-hydroxyisobutyrate > mandelate > lactate. The stability constants and enthalpy of formation of mono- and di-malonate complexes have also been measured.The mono-1,1-cyclopentanedicarboxylato-complexes are less stable than the corresponding malonate species. 

The measurement of stability constants of complexes of yttrium, lanthanide, and actinide ions with oxalate, citrate, edta, and 1,2-diaminocyclohexanetetra-acetate ligands has revealed that there is a slight increase in the stability of complexes of the /-electron elements, relative to the others. A series of citric acid (H cit) complexes of the lanthanides have been investigated by ion-exchange methods and the species [Ln(H2cit)]", [Ln(H2cit)2] , [Ln-(Hcit)], and [Ln(Hcit))2] were detected. Simple and mixed complexes of dl- and jeso-tartaric acid have been obtained with La " and Nd ions, and the stability constants of lactate, pyruvate, and x-alaninate complexes of Eu and Am " in water have been determined. 

Powell et al. [412] recently prepared the JnVlactates from Nd to Lu and obtained them as trihydrates. They also measured the stability constants of the lactate complexes but at lower ionic strength (p = 0.1 at 20° C) and obtained somewhat larger values for log ki (cf. acetate complexes at different ionic strengths). 

The stability constants of complexes of metal ions with different ligands are to some degree correlated. Almost perfect linear correlation between stability constants of aqueous hydroxo complexes on the one hand and acetate (slope 0.27), lactate (slope 0.61) and salicylate (slope 1,29) complexes on the other has been demonstrated [669] for Fe, Pb, Cu, Zn, Co, Ni, Cd, Mn, and Mg. The adsorption process can be... 

Table 8 Stability constants of aluminium-propionate and -lactate...

Stepwise formation constants and free energy, enthalpy, and entropy changes have been calculated for the 1 1, 1 2, and 1 3 complexes of AP" with malonate and succinate ions. Table 8 gives the calculated values for the stability constants of aluminium complexes with propionate and lactate ions in aqueous solutions, with I = 1. Solution calorimetry was used to determine values for the enthalpies of formation of tris(tropolonato)Al " and tris(4-methyltropolonato)Al " (Table 9) they were used to derive gas-phase enthalpies of formation, and hence the A1—O bond energies. ... 

Martell AE, Smith RM (1982) Critical Stability Constants, vol 5. Suppl. 1. Plenum, New York Smith RM, Martell AE (1989) Critical Stability Constants, vol 6. Suppl. 2. Plenum, New York Silva AMN, Kong XL, Hider RC (2009) Determination of the pKa value of hydroxyl group in the a-hydroxycarboxylates citrate, malate and lactate by C NMR implications for metal coordination in biological systems. BioMetals 22 771-778... 

A practical application of the spectral intensity of hypersensitive transitions in lanthanide ions is the determination of stability constants. Bukietynska et al. (1977, 1981a,b) have evaluated the stability constants of lanthanide complexes from the changes of the oscillator strength of hypersensitive transitions as a function of the ligand concentration. The method was applied to acetate, propionate, glycolate, lactate and a-hydroxyisobutyrate complexes of Nd ", Ho and Er +. Bukiet5mska et al. claim that this spectrophotometric method is superior to the potentiometric method, since the best results for the latter method can be obtained only for the first complexation steps. The stability constants evaluated at several temperatures have been used also to calculate the thermodynamic quantities AG, AH and AS. 

FiM also assumes a constant ruminal pH of approximately pH 6.2 and ignores the detrimental effects that low pH can have on ruminal metabolism. The system does, however, provide an estimate of whether rumen pH is likely to be altered through the calculation of a rumen stability value (RSV).The RSV of a feed is dependent on its fibre content, whether it is a concentrate or forage, and the potential acid load (PAL).The PAL content is a measure of the amoimt of acid that wUl be produced by the feed on incubation with rmnen liquor, expressed as meq/kg DM. Typically, hay will have a PAL of 800 meq/kg DM and barley 1150 meq/kg DM. The requirement for RSV is affected by cow age, milk yield and quality, and the feeding system used. For example, fourth-lactation cows fed a total mixed ration will have a lower RSV requirement than first-lactation animals fed concentrates twice daily in the parlour. If the RSV balance (RSV from diet - RSV requirement) is greater than +20, then it is assumed that no problems with acidosis should be encountered if it is below 0, then it is advised that the diet should be modified. 

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