Basicity Table

Basic Table 3-3 Parts of a Centrifugal Pump ance between these two faces prevents leakage of liquid out or air in. 

Substituted arylamines can be either more basic or less basic than aniline, depending on the substituent. Electron-donating substituents, such as — CH3, -NH2, and -OCH3, which increase the reactivity of an aromatic ring toward electrophilic substitution (Section 16.4), also increase the basicity of the corresponding arylamine. Electron-withdrawing substituents, such as —Cl, -NO2, and -CN, which decrease ring reactivity toward electrophilic substitution, also decrease arylamine basicity. Table 24.2 considers only -substituted anilines, but similar trends are observed for ortho and meta derivatives. 

Table 2 shows a strong correlation between the p7fa s of amines 11 and 8 with the most basic 11a proceeding to 98% conversion to product over 48 h at rt (Table 2, entry 1) and the least basic Table 2 (entries 5 and 6) exhibiting very low conversion to product. 

Fw. 21. I nax. of fho complex bands of iodine complexes as a function of the relative basicity (Table 10). 

A and B. This calculation is, of course, not very precise but it does correctly reflect the effect of methyl substitution on the basicity. Table 23 summarizes the values obtained in this way for all monomethyl derivatives and for the 7,12-dimethyl derivative of benz[a]anthracene (Mackor et al., 1956 Dallinga et al., 1958b). gives the figure of the total basicity, pA"(A) the value for ion A, pif(B) the value for ion B, and... 

Utilization of zeolite acidic strength in Cg-aromatics (xylens) systems is illustrated next. In the presence of strong acids, xylene isomers have varying basicity (Table 6.5), with m-xylene being the most basic and p-xylene the least basic among the Cg-aromatics [27]. Based on the basicity of the xylenes, the acidity of each zeolite can be properly adjusted to selectively adsorb m-xylene or p-xylene. As demonstrated in Figure 6.4, a more acidic zeolite such as NaY will selectively adsorb m-xylene from other Cg-aromatics [28, 29], In contrast. Figure 6.5 shows that a weaker acidic zeolite such as KY will selectively adsorb p-xylene from other Cg-aromatics [30, 31]. In both systems, toluene was used as the desorbent. 

Similar arguments allow an explanation of the change of stereochemistry observed with Grignard reagents when increasing the solvent basicity (Table VIII). The addition of a basic solvent (THF, DME) implies a modification of the carbon-magnesium MO, in which the latter become more contracted on the carbon atom (Scheme 16). As a consequence the nucleophile is smaller in size and the stereochemistry is shifted to retention (Tables VI and VIII). 

Bruno, T.J., and P.D. Svoronos Handbook of Basic Tables for Chemical Analysis, 2nd Edition, CRC Press, LLC., Boca Raton, FL, 2003,... 

Handbook of basic tables for chemical analysis/authors, Thomas J. Bruno, Paris D.N. Svoronos—2nd ed. p. cm. 

Rev. ed. of CRC handbook of basic tables for chemical analysis, cl989 Includes bibliographical references and index. 

This work began as a slim booklet prepared by one of the authors (T.J.B.) to accompany a course on chemical instrumentation presented at the National Institute of Standards and Technology, Boulder Laboratories. The booklet contained tables on chromatography, spectroscopy, and chemical (wet) methods, and was intended to provide the students with enough basic data to design their own analytical methods and procedures. Shortly thereafter, with the co-authorship of Professor Paris D.N. Svoronos, it was expanded into a more extensive compilation entitled Basic Tables for Chemical Analysis, published as a National Institute of Standards and Technology Technical Note (number 1096). That work has now been expanded and updated into the present body of tables. 

Bruno, T.J. and Svoronos, P.D.N., Basic Tables for Chemical Analysis, National Bureau of Standards Technical Note 1096, April 1986. 

Structural changes in the alkene portion of an enamine can also affect its basicity. Table 2 (equilibrium) and Table 4 (kinetics) contain a few examples, but these few data do not show the results of systematic variation of structure. 

When the phenol is kept constant, similar variations are observed for a series of methyl-snbstitnted pyridines of increasing basicity (Table 21). 

The pH value of 7 for pure water at 25°C is considered to be neutral, and values below 7 are considered acidic and above 7 basic. Table 1-2 illustrates the pH scale extending from —1 to -1-15. It is important to recognize that as the pH decreases, [H+] increases. A decrease in one pH unit reflects a 10-fold increase in H+ concentration. In... 

T.J.S. Bruno and D.N. Paris, Handbook of Basic Tables for Chemical Analysis, CRC Press LLC, 2003. ISBN... 

As the olefins and to a lesser extent the alkanes are basic one may expect the desorption to be favored by surface basic sites. In other words oxidative dehydrogenation of alkanes is expected to be easier on surface exhibiting basic properties. As a matter of fact the results given in table 5 from ref 41 show that Mg2V207 which is more basic as shown in table 4 is more selective for olefins in propane conversion and to a lesser extent for n-butane and isobutane oxidation reactions than the other two phases. Such a feature is even more pronounced for the samples with excess MgO at least for propane oxidation, samples which were also shown to present higher basicity (table 4). 

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