Phthalate ion

Rearrangements are also known to take place. For example, when the phthalate ion is heated with a catalytic amount of cadmium, the terphthalate ion (44) is produced ... 

The rate of formation of sulphoxides from sulphides and iodine in aqueous solution has been found to be relatively slow. It may be, however, accelerated by certain nucleophiles, such as phthalate ion S hydrogen phosphate ion and E(-cyclodextrin phosphate ion . The selective oxidation of JV-acetylmethionine and N-acetylmethionine methyl ester to the corresponding S-oxides was achieved using iodine in the presence of dicarboxylate ions. 

An alternative means of detection involves UV spectrophotometry, the mobile phase containing the strongly absorbing phthalate ion which gives a constant high absorbance baseline signal that displays negative peaks as the sample components elute from the separator column. No suppressor column is therefore needed and the sensitivity is comparable to conductometric detection. 

The P in KHP refers to phthalate. The phthalate ion is a benzene ring with two carboxyl groups on adjacent carbons. See Figure 5.8. Potassium hydrogen phthalate (KHP) is useful as a primary standard because it possesses all the qualities sought in a primary standard. See Section 4.5.2. 

The major conclusion which was reached from the work of Jarret and Saunders was that intramolecularly hydrogen-bonded protons generally give values of (p below the value for a similar proton which is not involved in an intramolecular hydrogen bond. For example, a value of (p of 0.77 was obtained for the hydrogen-bonded site in the maleate ion [12] compared to 0.94 for acetic acid. The value for the phthalate ion [10] was higher, (p = 0.95. The value of (p = 0.95 was obtained for the salicylate ion [22] in comparison to the result for phenol, tp = 1.13. 

Figure 3.22c illustrates the validity of eqn.(3.84) for the IEC separation of some inorganic anions. The counterion in this example is a mixture of monovalent and divalent phthalate ions. At the selected pH of 5.3 the average charge of the phthalate ions is 1.52. According to eqn.(3.84) this would result in slopes for monovalent solute ions of about 0.66 and about 1.3 for divalent ions. These figures correspond reasonably well with what is observed in figure 3.22b [368]. 

An alternative means of detection involves UV spectrophotometry, the mobile phase containing the strongly-absorbing phthalate ion which gives a... 

The amphoteric nature of wool was demonstrated in the early studies of Speakman and Hirst (1933), Elod (1933), and in particular by the complete acid-base titration curve obtained by Speakman and Stott (1934). Even earlier attempts had been made to determine the isoelectric point of wool by the methods indicated in Table XXIII. Some variation in the isoelectric point is to be expected because the pH at which the net charge, including bound ions, is zero depends on the nature and concentrations of ions in the aqueous environment. For example, Sookne and Harris (1939) have shown that the early electrophoretic value of Harris (1932) was affected by the absorption of phthalate ions from the buffer solutions. With acetate buffer they obtained values of 4.2 and 4.5 for powdered wool and cortical cells, respectively. The isoelectric points listed in Table XXIII are... 

Problem 24.8 Write the mechanism of the last step in the Gabriel amine synthesis, the base-promoted hydrolysis of a phthalimide to yield an amine plus phthalate ion. 

The chemiluminescence reactions of the phthalhydrazides (la-g) were carried out in the aerobic DMSO solution in the presence of BuOK. The chemiluminescence intensities relative to the luminol chemiluminescence are also described in Table 1. As expected from their strong fluorescence, If and Ig produced much stronger chemiluminescence than the others. Since their chemiluminescence spectra agreed well with the fluorescence spectra of the corresponding potassium phthalates, the emitters are the phthalate ions (2f and 2g) similar to the luminol chemiluminescence. 

In summary, control of the chemiluminescence efficiency as well as the emitter by the terminal substituents was demonstrated for the chemiluminescence reactions of 4-styrylphthalhydrazides. The strongly electron-donating character of the terminal substituents is coincident with the increase in the d>F values of the corresponding phthalate ions by a contribution of an electronic pull-push system, which provides an efficient chemiluminescence with the excited phthalate ions being the emitters. On the other hand, the energy transfer chemiluminescence takes place when the fluorescence of the phthalate ions is weak. 

Where represents phthalate ion, which are considered here as potential determining ions. Khl and Kl, are the equilibrium constants, obtained by fit to adsorption data. The adsorption density as a function of phthalate aqueous concentration is illustrated in Figure 2, where the solid line shows SCF/DLM model calculation with log A // , = 16.45, log/i , = 11.28, in addition to the constants for hematite surface hydroxyl species. The model yields a good estimation at higher adsorption densities, but it overestimates the adsorbed organics at lower solution concentration. 

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