A, basicity constant

We sometimes call the equilibrium constant in Equation (6.33) a basicity constant, and symbolize it as Kb. 

By analogy with the acids, we can define a basicity constant for the reaction of an organic base (i = B) with water ... 

As discussed in Section 3.10.3, in the gas phase the basicity of simple amines follows the order NMe3 > NHMe2 > NH2Me > NH3 because of the electron donating effect of the methyl (Me) groups. In solution, however, we can define a basicity constant as the equilibrium constant for the reaction shown in Equation 3.4. Note it is important to specify temperature, solvent (usually water) and solution ionic strength, 1 Basicity constants are related to the acid dissociation constants (/Q of the base s conjugate acid via the dissociation constant of water, K = 10 14 at 25 °C. Thus Kbx K = Kw. 

We found it convenient to compare acidities of carboxylic acids by measuring the extent to which they give up hydrogen ion to water the equilibrium constant for this reaction was called the acidity constant, Ka. In the same way, it is convenient to compare basicities of amines by measuring the extent to which they accept hydrogen ion from water the equilibrium constant for this reaction is called a basicity constant, K. ... 

Two conventions are used to measure the basicity of amines. One of them defines a basicity constant Ky, for the amine acting as a proton acceptor from water ... 

Section 22.4 Basicity of amines is expressed either as a basicity constant K, (p/fb) of the amine or as a dissociation constant (pA a) of its conjugate acid. 

Section 22.4 Basicity of amines is expressed either as a basicity constant of... 

Ceramic shaping is an inexhaustible subject, with a basically constant framework, but it is very complex and heterogeneous due to the plethoric parameters one encounters between the raw material and the finished product. The above article roughly describes the state of the art in terms of extrusion tools, pressure heads and dies. 

Comparison of the degree of crystallinity and the enthalpy change for the sample crystallized at 140 °C shows that the temperature-dependent denominator of eqn ]14] yields a basically constant degree of crystallinity between 160 and 200 °C... 

As we discussed in Section 1 14 it is more useful to describe the basicity of amines m terms of the pA a s of their conjugate acids than as basicity constants Always bear m mind that... 

Basicity constant Ki, (Section 1 14) A measure of base strength especially of amines... 

When one of the elements is solid, as in tire case of carbon in the calculation of the partial pressures of tire gaseous species in the reaction between methane and air, CO(g) can be used as a basic element together widr hydrogen and oxygen molecules, and thus the calculation of the final partial pressure of methane must be evaluated using the equilibrium constant for CH4 formation... 

The left-hand side of our equation says that fast fracture will occur when, in a material subjected to a stress a, a crack reaches some critical size a or, alternatively, when material containing cracks of size a is subjected to some critical stress cr. The right-hand side of our result depends on material properties only E is obviously a material constant, and G, the energy required to generate unit area of crack, again must depend only on the basic properties of our material. Thus, the important point about the equation is that the critical combination of stress and crack length at which fast fracture commences is a material constant. 

The equation of Knox et al. was not derived theoretically from a basic dispersion model, but the constants of the equation were determined by a curve fitting procedure... 

Ill spite of their importance, basicity constants rarely figure in descriptions of alkaloids. Figures for a series of alkaloids and related substances were published by Kolthoff in 1925 and have been extensively used. Recently a few more have been added by Schoorl, and Adams and Mahan have provided figures for the whole group of necines, the amino-alcohols resulting from the hydrolysis of the pyrrolizidine group of alkaloids. ... 

Various amines find application for pH control. The most commonly used are ammonia, morpholine, cyclohexylamine, and, more recently AMP (2-amino-2-methyl-l-propanol). The amount of each needed to produce a given pH depends upon the basicity constant, and values of this are given in Table 17.4. The volatility also influences their utility and their selection for any particular application. Like other substances, amines tend towards equilibrium concentrations in each phase of the steam/water mixture, the equilibrium being temperature dependent. Values of the distribution coefficient, Kp, are also given in Table 17.4. These factors need to be taken into account when estimating the pH attainable at any given point in a circuit so as to provide appropriate protection for each location. 

More specifically, the pi of any amino acid is the average of the two acid-dissociation constants that involve the neutral zwitterion. For the 13 amino acids with a neutral side chain, pi is the average of pKal and p/amino acids with either a strongly or weakly acidic side chain, pi is the average of the two lowest pKa values. For the three amino acids with a basic side chain, pi is the average of the two highest pKz values. 

Basicity constant, Kh (Section 24.3) A measure of base strength. For any base B, the basicity constant is given by the expression... 

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