M2 1000

Substituting for p2, p,, and pA in Eq. (117), we obtain, after rearranging

2.3 tf 2.3 M2 1000 1000J2

" 2.39c, 1 2300d2 2300

The values of molecular weight M2, liquid density d2 and apparent mole volume of salt <j) are adapted from the references [67, 68], and are

73.10 g mor', 0.944 g mol-1, 34.49 ml mol"1 for DMF, respectively. Substitute for these values in Eq. (121), and k is written as A^ = 0.0673-4.34x10"V (122)

(2). Expression for kp

Shoor and Gubbins [64] derive the following expression for the interaction energy between a nonelectrolyte molecule and the solution species forming the cavity:

Taking the derivative with respect to cs as ct —> 0, and inserting numbers for the various constants (T = 323.15K, the dipole moment of DMF /u2 =3.86xl0~18 esu cm), we can write r3(g;/2.3m

To assign a numerical value to kp, the mixture parameters £•* and er* must be related to those of the pure species. We use the following mixing rules:

Values of energy parameters £•*. for this system are evaluated from the famous Mavroyannis-Stephen equation:

where z. is electron number of species j , a. is its diameter (A) and a/ is its polarizability (A3). Molecular polarizability a is obtained by Langevin-Debye equation:

where D is dielectric constant (esu cm, "esu" is Electro Static Unit), M is molecular weight (g mol"1), d is liquid density (g ml"1) and N0 is Avogardro's number, 6.023 X 1023.

The data necessary for solving Eq. (125) through Eq. (128) are listed in Table 11, in h v is molar volume(ml mol"').

Making these substitutions in Eq. (124), we arrive at a final expression for kB:

+ —x 1,168x 10l7f—)1/2f—)"2^(<ti + <t2)3 + 3.78 x 1(T2-

Table 11

Data for calculating salting coefficients

Table 11

Data for calculating salting coefficients

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