Medium effects on transfer enthalpies of electrolytes from water to organic solvents and to water-organic mixtures

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A C T A U N I V E R S I T A T I S L O D Z I E N S I S FO L IA CH I M I C A 10, 1993

B oż enna Now icka*, Henryk P i e k a r s k i * M E D I U M E F F E C T S O N T R A N S F E R E N T H A L P I E S OF E L E C T R O L Y T E S F R O M W A T E R TO O R G A N I C S O L V E N T S

A N D TO W A T E R - O R G A N I C M I X T U R E S

E n t h a l p i e s of transfer, A trH°° of e l e c t r o l y t e s from w ater to s ev eral or g a n i c s o l vent s were c o r r e l a t e d with p a r a m e t e r s d e s c r i b i n g some p r o p e r t i e s of the solvents. The i n f lu ence of both c at ion and anion kind and size on the r e l ativ e c o n t r i b u t i o n s of the s ol vent p r o p e r t i e s to the o b s e r v e d v a r i a t i o n of the A t r H°° of the salts was analysed. The s im ilar c o r r e l a t i o n s of t r a nsfe r e n t h a l p i e s of salts from water to w a t e r - o r g a n i c m i x t u r e s with a c o m p o s i t i o n c o r r e s p o n d i n g to o b s e r v e d A ^ H 00 m a x i m u m were exa mined.

I N T R O D U C T I O N

T h e r m o c h e m i c a l p r o p e r t i e s of e l e c t r o l y t e s o l u t i o n s in non- - a q ueou s and m i x ed w a t e r - o r g a n i c solvents depend, to large ext ent on p h y s i c o - c h e m i c a l p r o p e r t i e s of the or g a n i c c o m p one nt. In the former case, the d i f f e r e n c e s in dissolution, or b et ter in s o l v a tion e n t h a l p i e s of the sol ute reflect v a r i a t i o n of the o rg anic so l v e n t p r o pert ies. In the latter case, the d i s s o l u t i o n e n t h a lpie s A s o ^ H ® as a fun ctio n of the m i x ed so l v e n t c o m p o s i t i o n often exh i b i t a co m p l e x shape with c h a r a c t e r i s t i c m a x ima w it hin the w a t e r - r i c h region. The a p p e a r a n c e of these m a x i m a in some w a t e r - o r g a n i c m i x t u r e s is g e n e ral ly a t t r i b u t e d to the c h a n g e of the m i x ed s ol vent s t r u c t u r e or to the h y d r o p h o b i c h y d r a t i o n and

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D e p a r t m e n t of P h y sica l Che mistry, U n i v e r s i t y of Łódź, P o m o r ska 18, 91- 416 Ł ódź, Poland.

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o v e r l a p i n g of the h y d r o p h o b i c cos pher es. Therefore, the m i x ed s ol vent with a c o m p o s i t i o n c o r r e s p o n d i n g to the As o l H°° m a x i m u m has some s pe cial features. The h e i g h t of the m a x i m u m on the A s o l H 0 0 = f (mixed so l v e n t c o m p o s i t i o n ) curve in a g i v en m i x t u r e de p e n d s on the ki n d of d i s s o l v e d salt. On the other hand, for the same e l e c t r o l y t e d i s s o l v e d in d i f f e r e n t m i x ed s o l v e n t s the he i g h t s of the m e n t i o n e d As q 1H°° m a x ima also d if fer s i g n i f i c a n t l y from each other. As an i l l u s t r a t i o n of this b e h a v i o r the e n t h a l p i e s of transfer, of NaBPh^ from water to several w a t e r - o r g a n i c mix ture s, A ^ H 00 de f i n e d as:

A t r H° ° = A s o l H°°(Mixt) ’ A s o l H°°(Water) (1)

are p r e s e n t e d in Fig. 1 as a f u n ctio n of the m i x ed s o l v e n t c o m p os ition.

In order to o b t a i n some i n f o r m a t i o n s about the f ac tors that i n f l u e n c e the o b s e r v e d p r o p e r t i e s of the system, the s o - c a l l e d m u l t i p l e linear r e g r e s s i o n a n a l y s i s (MLRA) can be app lied. In this app roach, the a n a lyse d f u n ctio n (for ins tanc e the e n t halp y of tra nsfe r) is c o r r e l a t e d with the p a r a m e t e r s d e s c r i b i n g s e l e c t e d p r o p e r t i e s of the s y s tem com pone nts. H a v i n g at our d is p o s a l a n um ber of data on the d i s s o l u t i o n e n t h a l p i e s of e l e c t r o l y t e s in d i f f e r e n t or g a n i c and m ix ed w a t e r - o r g a n i c s o l v e n t s 1 we d e c i d e d to check whe t h e r the use of the m e n t i o n e d MLRA m e t h o d en a b l e s finding which of the so l v e n t p r o p e r t i e s and to what ext ent i n f l u e n c e the o b s e r v e d t h e r m o c h e m i c a l b e h a v i o r of the sol utio ns. Mor eove r, from obt a i n e d c o r r e l a t i o n e q u a t i o n s r e f e r r i n g to d i f f e r e n t e l e c t r o l y t e s we e x p e c t e d to c o n c l u d e a bout the i n f l u e n c e of the kind of ion on the r e l a t i v e c o n t r i b u t i o n of the so l v e n t p r o p e r t i e s to the total v a r i a t i o n of the a ^ H 00 val ues w i t h i n the e x a m i n e d set of solvents.

N u m e r o u s m u l t i p a r a m e t r i c c o r r e l a t i o n e q u a t i o n s are d e s c r i b e d in the lit erat ure. The K o p p e 1-P a 1 m [2] , K r y g o w- s k i-F a w c e t t [ 3 , 4 ] and A b r a h a m - K a m l e t - T a f t [5-7] ones b e l o n g to the best known. All the m e n t i o n e d e q u a t i o n s

1 The a p p r o p r i a t e data were taken from ref. [l] u n l e s s s ta ted o t h e r w i s e .

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Fig. 1. E n t h a l p i e s of transfer, A ^ H 00 of N a B P h ^ from w a t er to w a t e r - o r g a n i c so l v e n t mix ture s. MeO H - m e t h ano l, EtO H - ethanol, t B uUH t e r t b u t a n o l , THF t e t r a h y d r o f u r a n , D M S O d i m e t h y l s u l f

-oxide, S - s u l f o l a n e

are a linear c o m b i n a t i o n of s e l ecte d p a r a m e t e r s d e s c r i b i n g some p r o p e r t i e s of the s y s t e m com pone nts, but they c o n t a i n d i f f e r e n t n u m b e r and d i f f e r e n t ki n d of the par a m e t e r s . The K o p p e l - P a 1 m [2] e q u a t i o n has a form:

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where A and B are p a r a m e t e r s m e a s u r i n g the acc e p t o r and d on ator p r o p e r t i e s of the solvent, res pectively, while Y and P are n o n - s p e c i f i c p a r a m e t e r s m e a s u r i n g the s ol vent p o l a r i t y and its p o l a r i z a b i l i t y . K r y g o w s k i and F a w c e t t sho wed that in most c a s es it is e no ugh to take into a c c o u n t only s p e c i f i c s o l u t e - s o l v e n t i n t erac tions , d e s c r i b e d by the s ol vent a ci dity and b a s i c i t y [3, 4]. The m e n t i o n e d au t h o r s p r o p o s e d the D i m r o t h - R e i c h a r d t (Ey) p a r a m e t e r as the a ci dity f u n c t i o n and G u t m a n n donor n u m b e r (ON) for the so l v e n t b a s i c i t y i l l u s t r a t i o n and their (KF) e q u a t i o n has a form:

Q = Q 0 + a E T + bDN (3)

The s im ilar e q u a tio n, with K a m l e t - T a f t b a s icit y f u n c t i o n ( (3K y) i ns tead of the DN was used in our rec ent paper [8] for the c o r r e l a t i o n of t r a n s f e r e n t h a l p i e s of Ph^ PCl and N a B P h ^ from w a t er to 10 w a t e r - o r g a n i c sol v e n t m i x t u r e s with the c o m p o s i t i o n c o r r e s p o n d i n g to the p o s i t i o n of the A ^ H 00 m a x i m u m .

Both m e n t i o n e d above e q u a t i o n s (KP and KF) do not c o n t a i n any p a r a m e t e r s d e s c r i b i n g , or at least tak ing into ac c o u n t to some ex t ent the so l v e n t str uctu re. One of such st r u c t u r a l p a r a m e t e r s , na m ely c o h e s i v e e n e r g y den sity , 8 (H) is i n c l u d e d into c o r r e l a t i o n e q u a t i o n p r o p o s e d by A b r a h a m , K a m l e t and T a f t [5-7], w h i c h for a s o l ute in several s o l v e n t s has the f o l l o w i n g form:

XYZ = ( X Y Z ) q + S97* + a a x + bfy + mS^(H) (4) *

w he re 37^ is a p a r a m e t e r d e s i g n a t i n g the sol vent d i p o l a r i t y / p o l a - r i z a bil ity, oi^ and (3^ d en ote ac i d i t y and b a s i c i t y p a r a m e t e r of the so l v e n t and S j ( H) is its c o h e s i v e energy density.

R E S U L T S

a. E n t h a l p i e s of t r a n s f e r o f N a l f r o m w a t e r to p u r e o r g a n i c s o l v e n t s .

The a p p l i c a t i o n of the K o p p e l - P a l m e q u a t i o n for tra n s f e r e n t h a l p i e s , a ^ H 00 of Nal from water to 17 org a n i c s o l v e n t s

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T a b l e 1 E n t h a l p i e s of t r a nsfe r A ^ H 00 (kJ • m o l - 1 ) of Nal from w a t er to

or g a n i c s o l vent s at 298 .15 K S ol vent A t r H“ Sol v e n t A t r H ~ Met h a n o l -22.3 F o r m a m i d e -23 .48 E th anol -16.95 DMF -47 .53 P ro p a n o l - I B .7 9 a DMA -44.18 2 - P r o p a n o l - 2 1 . 3 9 a A ce tone -35.93 n - B u t a n o l - 21.7b 2 - B u t a n o n -33.5 i - B u tan ol -25.6 DMSO -40 .63 2-B utan ol -26.14 HMPT -58 .63 Et h y l e n e glycol -24.23 Pyr i d i n e -43.0 A c e t o n i t r i l e -21.63 a R e f e r e n c e [lOj . 13 R e f e r e n c e [ll] . DMF - N,N-dimettiylformamide, DMA - N ,N - d i m e t h y l a c e t a m i d e , DMSO - d i m e t h y l s u l f o x i d e , HMPT - h e x a m e t h y l p h o s p h o r i c triamide.

p r e s e n t e d in Tab. 1 g i v es the c o r r e l a t i o n with the c o r r e l a t i o n c o e f f i c i e n t r = 0.936. A b et ter result is o b t a i n e d w he n we use the A b r a h a m - K a m l e t - T a f t equ ation. For the same set of data we hav e :

A t r H°°= (43.1 + 8.1)31^ + (8.8 + 6 . 0 ) a 1

-- (21.5 + 5.6)i31 + (0.08 + 0 . 0 3 ) s J ( H ) (5)

wit h r = 0.966, disp. = 3.91.

As it is k n o w n the a scale of a ci dity d e s c r i b e s the a bi lity of a m o l e c u l e to d o n a t e a p ro ton in a s o l u t e - t o - s o l v e n t h y d r o gen bond [5-7]. For the ionic s o l u t i o n s the a p p l i c a t i o n of oi scale can be dou btfu l. T h e r e f o r e we have r e p l a c e d this p a r a m e t e r in the AKT e q u a t i o n by E y — D i m r o t h - R e i c h a r d t a ci dity fun ction. This r e p l a c e m e n t p r a c t i c a l l y does not i n f l u e n c e the a c c u r a c y of

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t h e fit. T h e o b t a i n e d e q u a t i o n t h a t c o r r e l a t e s b e s t w i t h the A t r H °° v a l u e s h a s f o l l o w i n g f or m: A t r H°° = _ ( 5 6 -6

t

4.4)ot* + ( 0 . 2 1 + 0 . 1 4 ) E T -- ( 2 1 . 2 + 5 . 1 ) (3j + ( 0 . 1 0 + 0 . 0 2 ) S ^ ( H ) (6) w i t h r = 0 . 9 6 7 , d i s p . = 3 .8 8. A t rH “ (expl)[kJmol 11

Fig 2. C o m p a r i s o n of the Nal t r a nsfe r e n t h a l p i e s from water to or g a n i c s o l v e n t s d e t e r m i n e d e x p e r i m e n t a l l y and c a l c u l a t e d from

e q . 5

1 - water; 2 - m e t h a n o l ; 3 - eth anol; 4 - pro pano l; 5 - 2 - p ropa - nol; 6 - butanol; 7 - i-b utanol; 8 - 2-b utanol; 9 - e t h y l e n e glycol; 10 - a c e t o n i t r i l e ; 11 - for mami de; 12 - N ,N - d i m e t h y I f o r - mamide; 13 - N ,N - d i m e t h y l a c e t a m i d e ; 14 - acetone; 15 - 2-b utan on; 16 - d i m e t h y l s u l f o x i d e ; 17 - h e x a m e t h y l p h o s p h o r i c tri amid e; 18

-p y r i d i n e

A c o m p a r i s o n of the Nal t r a nsfe r e n t h a l p i e s d e t e r m i n e d e x p e r i m e n t a l l y wit h those c a l c u l a t e d from the above e q u a t i o n is gi v en in Fig. 2. The n u m e r i c a l values of the p a r a m e t e r s c h a r a c ter i s i n g the a n a l y s e d s o l v e n t s w er e taken from ref. [9].

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b. E n t h a l p i e s of t r a n s f e r of o t h e r e l e c t r o l y t e s f r o m w a t e r to p u r e o r g a n i c s o l v e n t s .

In order to c o m p a r e the inf luen ce of the c at ion a n d /or the a ni on c ha nge on the p r e s e n t e d c o r r e l a t i o n we p e r f o r m e d the a n a l o g o u s c a l c u l a t i o n s for the t r a nsfe r e n t h a l p i e s of other s al ts h a v i n g the same c a t i o n or the anion. The t r a n s f e r e n t h a l p i e s are k no wn only for lim ited n u m b e r of d i f f e r e n t sol vents. The refo re, we have c o r r e l a t e d the e n t h a l p i e s of t ra nsfer, A ^ H 00 for the salts: Nal, NaBPh^, NaClO^, KI, Ph^AsI from water to the same set of org a n i c s o l v ent s, namely: m e t h ano l, eth anol, n-p r o p a n o l , a c e t o n i t r i l e , ace tone, N,N - d i - m e t h y l f o r m a m i d e , N ,N - d i m e t h y l a c e t a m i d e , d i m e t h y l s u l f o x i d e and h e x a m e t h y l p h o s p h o r i c triamide, using the equ atio n:

A t r H°°= ( A t r H°°)0 + S3T* + a E T + b(3x + mS^(H) (7)

The o b t a i n e d v a l u e s of the c o e f f i c i e n t s : s, a, b, m and the c o r r e l a t i o n c o e f f i c i e n t s , r for each of the salts are p r e s e n t e d in Tab. 2. In the same table we c o l l e c t e d the r e l ativ e c o n t r i b u t i o n s of the so l v e n t pro p e r t i e s , i l l u s t r a t e d by , Ey, (3^, and S ^ (H ) to the a n a l y s e d v a r i a t i o n of A ^ H 00. The two sets of the s, a, b and m v a l ues for Nal s o l u t i o n s g iv en in eq. 6 and in Tab. 2 d if fer each other. This is so since they r e l a t e to two d i f f e r e n t g r o u p s of solvents.

c. E n t h a l p i e s of t r a n s f e r of e l e c t r o l y t e s f r o m w a t e r to w a t e r - o r g a n i c s o l v e n t m i x t u r e s .

As was m e n t i o n e d ear l i e r we int ende d to an a l y s e the effect of the o r g a n i c c o s o l v e n t p r o p e r t i e s on the h e i g h t of A g yH°°maxima of e l e c t r o l y t e s , c h a r a c t e r i s t i c for many a q u e o u s b i n a r y mix tures. The refo re, by the use of the MLRA m e t h o d we c o r r e l a t e d the tra n s f e r e n t h a l p i e s of N a B P h 4 , P h 4 PCl and B u 4NBr from water to the w a t e r - o r g a n i c c o s o l v e n t mix ture s, c o m p o s i t i o n of c o r r e s p o n d i n g to the A s o l H°° (or A ^ H 00) m a x i m u m wit h the p a r a m e t e r s d e s c r i b i n g the c o s o l v e n t features. The same a n a lysi s was p e r f o r m e d also for Nal s o l u t i o n s in the m i x e d sol vents. The A , H 00 f u n c t i o n for Nal has no m a x i m u m in the m i x t u r e s of

sol

w a t er with acetone, s u l f o l a n e and ace t o n i t r i l e . T h e r efo re, the e n t h a l p i e s of tra n s f e r of this salt from w a t er to the m e n t i o n e d

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T a b l e 2 C o e f f i c i e n t s of the e q u a t i o n 5 c o r r e l a t i n g the e n t h a l p i e s of t r a n s f e r of e l e c t r o l y t e s from water to o rg anic s o l v e n t s and p e r c e n t a g e c o n t r i b u t i o n s of s e l e c t e d p r o p e r t i e s of s o l v e n t s to v a r i a t i o n of A ^ 00 C o e f f i c i e n t s of eq. 5 Nal N a C 1 0 4 N a B P h 4 s a b m r d i s p . * %JT % Et %|3 % 5 2(H) n a - 5 6 . 3+8 .9 -0.2 + 0.2 - 2 1 . 3 + 9 . 9 +0. 1 0 + 0 . 0 3 0.967 5.35 33 4 17 39 10 - 7 3 . 6 + 1 3 . 3 ( + 0 .07+ 0.3) - 1 5 . 1 + 1 3 . 4 + 0 . 1 5 + 0 . 0 4 0.969 7.04 32 ( 1) 10 51 10 - 7 4 . 7 + 1 6 . 0 + 0.5 + 0 .4 - 2 9 . 7 + 1 7 . 9 + 0 . 1 0 + 0 . 0 5 0.938 9.97 32 8 17 30 10 C o e f f i c i e n t s of eq. 5 KI P h 4 AsI B u 4 NBr s a b m r d i s p . HJI* %e t %|3 % S 2(H) n a - 6 8 . 4 + 7 . 0 - 5 . 9+5. 3 +0. 1 3 + 0 . 0 1 0.975 4.42 38 4 53 10 - 4 9 . 3+7 .3 + 0 . 3 6 + 0 . 1 6 (-3.1 + 7.3) +0. 0 6 + 0 . 0 2 0.957 4.20 42 10 (3) 36 10 + 8 . 3 + 5 .6 + 0 . 7 5 + 0 . 1 7 -0 .10+ 0.02 0.948 3.53 8 25 65 9 g

W ater and 8 or 9 or g a n i c s o l vent s as m e n t i o n e d in the p a p e r .

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T a b l e 3 C o e f f i c i e n t s of the e q u a t i o n 5 c o r r e l a t i n g the e n t h a l p i e s of t r a n s f e r of e l e c t r o l y t e s from water to w a t e r - o r g a n i c m i x t u r e s with the c o m p o s i t i o n c o r r e s p o n d i n g to the Atr.H°° m a x i m a of o r g a nic s a l ts and p e r c e n t a g e c o n t r i b u t i o n s of s e l e c t e d p r o p e r t i e s of s o l v e n t s to v a r i a t i o n of H œ tr C o e f f i c i e nts of eq. 5 Na I P h 4PCl NaBPh. 4 Bu^ NBr ( A t r H°°>o ( - 5 . 2 + 6 . 8 ) 3 4 . 4 + 1 0 . 6 1 0 8 . 8 + 2 4 . 3 ( - 4 2 . 2 + 4 8 . 1 ) s - 1 1 . 4 + 3 . 2 - 4 0 . 1 + 5 . 0 - 5 0 . 5 + 1 1 . 5 1 0 . 6 + 1 3 . 5 a (- 0 . 1 0 + 0 . 1 4 ) (0 . 13+0 .22) - 1 . 9 + 0 . 5 1.4+1.0 b 10 . 4+2. 2 2 0 . 2+3. 5 57 . 6+8. 0 3 4 . 7 + 9 . 6 m 0 .02+ 0.01 ( - 0 .01+ 0 .02) 0. 1 0 + 0 . 0 4 - 0 . 1 2 + 0 . 0 6 r 0.965 0.992 0.985 0.972 d i s p . 1.43 2.22 5.11 _5.02 n l l a lla l l a 9 b %3T* 27 53 ₂₀ ₍₆₎ % E T (8) ( 6) 25 24 %(i 33 35 30 22 % S 2(h) 25 (5) 23 43 n - n um ber of solvents. g

Water and m i x t u r e s of water with: m e t h ano l, eth anol, n- -pr opanol, iso pro p a n o l , t e r t - b u t a n o l , acetone, t e t r a h y d r o f u r a n , h e x a m e t h y l o p h o s p h o r i c tri amide, sul fola ne, a c e t o n i t r i l e .

b Water and m i x t u r e s of water with: eth anol , ter t - b u t a n o l , ace tone, sul fola ne, ace t o n i t r i l e , d i m e t h y l s u l f o x i d e , N , N - d i m e - t h y l f o r m a m i d e , N , N - d i m e t h y l a c e t a m i d e .

The v al ues given in p a r e n t h e s e s are s t a t i s t i c a l l y u n s i g n i f i cant.

m i x t u r e s wit h the c o m p o s i t i o n c o r r e s p o n d i n g to the At r H°° m ax ima of o r g a n i c s a l ts w er e used for this a n a l y s i s ( w a t e r - a c e t o n e : 10 m o l % , w a t e r - s u l f o l a n e : 2 m ol % and w a t e r - a c e t o n i t r i l e : 6 mol% of the o r g a n i c cos o l v e n t ) . S i m i l a r l y as for the e l e c t r o l y t e s o lu t i o n s in pure o r g a n i c solvents, the m o d i f i e d AKT equ a t i o n (eq. 7) was a p p l i e d here. S in ce the o r g a n i c c o m p o n e n t of the

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m i x e d s ol vent w i t h i n the high water con t e n t can be as s u m e d as one of the sol u t e s (an e l e c t r o l y t e is the other one), the values

* 2

of the , Ej, (3^ and 5j(H) p a r a m e t e r s were taken the same as for pure o r g a n i c c o m p oun ds. The o b t a i n e d values of s, a, b and m c o e f f i c i e n t s , the r e g r e s s i o n c o e f f i c i e n t , r and the rel a t i v e c o n t r i b u t i o n s of the sol v e n t p r o p e r t i e s to the e x a m i n e d v a r i a tion of A ^ H 00 are p r e s e n t e d in Tab. 3.

C O N C L U S I O N S

It is p o s s i b l e to c o r r e l a t e the t r a nsfe r e n t h a l p i e s of e l e c t r o l y t e s from w a t er to di f f e r e n t or g a n i c s o l v e n t s with the p a r a m e t e r s c h a r a c t e r i s i n g these solvents. Also the e n t h a l p i e s of tra n s f e r of salts from w at er to the w a t e r - o r g a n i c mix ture s, c o m p o s i t i o n of c o r r e s p o n d i n g to the Atl.H°° m a x i m u m a p p e a r e d to be a linear c o m b i n a t i o n of p a r a m e t e r s d e s c r i b i n g the o rg anic c o s o l v e n t .

The r e l a t i v e c o n t r i b u t i o n of so l v e n t b a s icit y d o m i n a t e s over the c o n t r i b u t i o n of the s o l v e n t a ci dity (Tab. 2, 3). The o b s e r v e d d e p e n d e n c e is true for all ana l y s e d s o l v e n t s (both s i n gle and m i x ed ones) and for all but Bu^NBr of the e x a m i n e d salts. This o b s e r v a t i o n seems to p o i nt at the d o m i n a n t role of c a t i o n s o l v a t i o n w i t h i n the a n a l y s e d set of sol vents. The o r g a n i c anion, that is h y d r o p h o b i c a l l y h y d r a t e d in w a t e r and in w a t e r - o r g a n i c m i x t u r e s does not c h a n g e the o b s e r v e d seq uence.

In the case of the t r a n s f e r e n t h a l p y of the salts from water to s i n g l e or g a n i c s o l v e n t s the i n c reas e of the o r g a n i c c at ion size d e c r e a s e s the r e l a t i v e c o n t r i b u t i o n of ac i d - b a s e i n t e r a c t i o n s in the total v a r i a t i o n of the A, H00. The

+ + tr

r e p l a c e m e n t of Na or K c a t i o n by an or g a n i c one r e v e r s e s the s e q u e n c e of a ci dity and b a s i c i t y con t r i b u t i o n s .

The bi g g e s t c o n t r i b u t i o n s in the A -trH°° v a r i a t i o n w i t h i n the set of the a n a l y s e d o r g a n i c sol vents, for all i n v e s t i g a t e d salts are g i v en by (Tab. 2):

*

- 37 - so l v e n t p o l a r i z a b i l i t y / d i p o l a r i t y , what was e x p e c t e d due to the p r e s e n c e of the ionic c ha rge as well as the s i g n i f i c a n c e of the i o n - d i p o l e i n t erac tions ,

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o

- 8 (H) - c o h e s i v e ene rgy density, as a p a r a m e t e r c o n n e c t e d with the s ol vent s t r u c t u r e c h a nge under i n f l u e n c e of the ions, and i n c l udi ng both the h y d r o g e n bond c o n t r i b u t i o n and the di- p o l e - d i p o l e i n t erac tions .

However, it s h o u l d be n o t ed that the s t a t i s t i c a l a n a l y s i s m e t h o d a pp lied in this work m a k es it p o s s i b l e to d e t e r m i n e the c o n t r i b u t i o n s of s e l e c t e d p r o p e r t i e s of the s o l v e n t s to the total v a r i a t i o n of the A trH°° values w h i ch are true only w it hin a given set of solvents. The inc reas e of n u m ber of e x a m i n e d s o l v e n t s h a v ing d i f f e r e n t p r o p e r t i e s w o u ld s o m e w h a t c h a n g e the c a l c u l a t i o n results. Unf or t u n a t e l y , the t r a n s f e r e n t h a l p i e s of e l e c t r o l y t e s n e c e s s a r y for that a n a l y s i s are k n o w n only for a l im ited n u m ber of s in gle s o l v e n t s and their m i x t u r e s with water.

R E F E R E N C E S

[1] G. M. P o 1 t o r a c k i i , T e r m o d i n a m i c h e s k i e k h a r a k t e r i - stiki n i e v o d n y k h r a s t v o r o v e l e k t r o l i t o v , [Thermodynamic cha r a c t e r i s t i c s of n o n a q u e o u s e l e c t r o l y t e s o l u t i o n s ] , Khi miya, L e n i n g r a d 1984.

[2] I . A . K o p p e 1, V . A . P a 1 m, [in:] A d v a n c e s in linear free e ne rgy r e l a t i o n s h i p s , Ed. by N. B. C h a p m a n , 3. S h o r t e r , P l e n u m Publ. Co., New York 1972, Chapt. 5. [3] T . M . K r y g o w s k i , W . R . F a w c e t t , J . Am. Chem.

Soc., 97, 2143 (1975).

[4] W. R. F a w c e t t , T . M . K r y g o w s k i , Aust. J. Chem., 20, 2115 (1975).

[5] M. J. K a m 1 e t, J.-L. M. A b b o u d, R. W. T a f t , Prog. Phys. Org. Chem., _13.> (1981).

[6] M. H. A b r a h a m, M. J. K a m 1 e t, R. W. T a f t , 3. Chem. Soc., P e r k i n Trans. 2, 2_, 923 (1982).

[7] M. J. K a m 1 e t, J.-L. A b b o u d , M. H. A b r a h a m , R. W. T a f t, J. Org. Chem., 48., 2877 (1983).

[8] S. T a n i e w s k a-0 s i ń s k a, B. N o w i c k a, A. P i e t r z a k , T h e r moc him. Acta, in press.

[9] Y. M a r c u s, Ion sol vation, Ed. by Wiley, New York 1985. [10] S. T a n i e w s k a-0 s i ń s k a , A. P i e k a r s k a ,

A. B a 1 d, A. S z e j g i s, Phys. Chenr. Liq., 2.1, 217 (1990).

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[li] S. T a n i e w s k a-0 s i ń s k a , A. P i e k a r s k a , A . B a 1 d , A . S z e j g i s , J. Chem. Soc. F a r a d a y Trans. 1, 85., 3709 ( 1989).

B oż enna Now icka, H en ryk P i e k ars ki W PŁ YW W Ł A S N O Ś C I R O Z P U S Z C Z A L N I K A NA ENT A L P I Ę P R Z E N I E S I E N I A E L E K T R O L I T Ó W Z WODY DO R O Z P U S Z C Z A L N I K Ó W O R G A N I C Z N Y C H I M I E S Z A N I N W O D N O - O R G A N I C Z N Y C H E n t a l p i e p r z e n i e s i e n i a ( A ^ H 00) e l e k t r o l i t ó w z wody do s z e r e gu r o z p u s z c z a l n i k ó w o r g a n i c z n y c h zo s t a ł y s k o r e l o w a n e z p a r a m e trami o p i s u j ą c y m i w y b r a n e w ł a s n o ś c i r o z p u s z c z a l n i k ó w . P r z e a n a l i z o w ano w p ł yw ro d z a j u i w i e l k o ś c i za r ó w n o kat ionó w, jak i a ni onów na w z g l ę d n e ud z i a ł y w y b r a n y c h w ł a s n o ś c i r o z p u s z c z a l n i k a w c a ł k o witej z m i e n n o ś c i A ^ H 00 b a d a n y c h soli. A n a l o g i c z n e k o r e l a c j e o d n o s z ą c e się do e n t a l p i i p r z e n i e s i e n i a soli z wody do m i e s z a n i n w o d n o - o r g a n i c z n y c h o s k ł a d z i e o d p o w i a d a j ą c y m m a k s i m u m A. H 00 z o stały r ów nież z n a l e z i o n e i p r z e d y s k u t o w a n e . r