Acid strengths tables

The more acidic the site the more pronounced the thermal effect should be. Taniguchi demonstrated that there is a close relationship between the values of differential heats of ammonia adsorption on different catalysts and their acid strength (Table 1)... 

The monosaccharides found in living systems are mostly mono- and di-phosphate esters. Of greatest importance in animal metabolism are the three esters (10.11), which also occur in plant life, particularly fruit (Chapter 12.3). They have high water solubilities and high acid strengths (Table 5.26). Individual glucose phosphates vary greatly in their hydrolytic behaviour (Chapter 5.6). 

For the methyl-substituted compounds (322) the increase in AG and AHf values relative to the unsubstituted thiazole is interpreted as being mainly due to polar effects. Electron-donating methyl groups are expected to stabilize the thiazolium ion, that is to decrease its acid strength. From Table 1-51 it may be seen that there is an increase in AG and AH by about 1 kcal mole for each methyl group. Similar effects have been observed for picolines and lutidines (325). 

Table 14 2 repeats some approximate data presented earlier m Table 1 7 for the acid strengths of representative hydrocarbons and reference compounds... 

Perfluorinated carboxylic acids are corrosive liquids or solids. The acids are completely ionized in water. The acids are of commercial significance because of their unusual acid strength, chemical stabiUty, high surface activity, and salt solubiUty characteristics. The perfluoroaLkyl acids with six carbons or less are hquids the higher analogues are soHds (Table 1). 

The acidic strength of various quinoxaline derivatives is also listed in Table II. -Methyl groups have an acid-weakening effect and quinoxalin-2-one (2-hydroxyquinoxaline) is, as expected, a weaker acid than quinoxaline-2-thione (2-mercaptoquinoxaline), The marked enhancement of the acidic strength of 5-hydroxyquinoxaline 1-methiodide compared to 5-hydroxyquinoxaline itself, is due to the electron-attracting property of the positively charged nitrogen, ... 

Tables of KA furnish a quantitative measure of acid strengths with which we can compare different acids and predict their properties. Several values of KA are given in Table 11-IV.

We see in Table 11-IV that the equilibrium view of acid strengths suggests that we regard water itself as a weak acid. It can release hydrogen ions and the extent to which it does so is indicated in its equilibrium constant, just as for the other acids. We shall see that this type of comparison, stimulated by our equilibrium considerations, leads us to a valuable generalization of the acid-base concept. 

Moving down in a column is equivalent in many respects to moving to the left in the periodic table. Since we find basic properties predominant at the left of the periodic table in a row, we can expect to find basic properties increasing toward the bottom of a column. Thus the base strength of the alkaline earth hydroxides is expected to be largest for barium and strontium. The greatest acid strength is expected for beryllium hydroxide. 

The log rate versus acid strength curve for the latter compound is of the exact form expected for reactions of the free base, whilst that of the former compound is intermediate between this form and that obtained for the nitration of aniline and phenyltrimethylammonium ion, i.e. compounds which react as positive species. That these compounds react mainly or entirely via the free base is also indicated by the comparison of the rate coefficients in Table 8 with those in Table 5, from which it can be seen that the nitro substituent here only deactivates weakly, whilst the chloro substitutent appears to activate. In addition, both compounds show a solvent isotope effect (Table 9), the rate coefficients being lower for the deuterium-containing media, as expected since the free base concentration will be lower in these. 

Kilpatrick et al.111 measured the rate of desulphonation of mesitylenesulphonic acid in excess of 12-13.5 M sulphuric acid. The rate coefficients are given in Table 43 (p. 73), and these were determined by spectrophotometrically measuring the concentration of sulphonic acid present at equilibrium, after reacting the sulphonic acid with the sulphuric acid of appropriate concentration again the increase in rate of desulphonation with increase of acid strength is much less than the increase in the rate of sulphonation. The increase in rate of desulphonation of mesitylenesulphonic acid with increasing acid concentration was less than that for 1,2,4,5-tetra-, 1,2,3,5-tetra-, and penta-methylbenzenesulphonic acids703 (Table 244) the... 

TABLE 10.5 Correlation of Acid Strength and Oxidation Number... 

TABLE 10.6 Correlations of Molecular Structure and Acid Strength... 

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