Ionic solutions under high pressures V : pressure effects...

TitleIonic solutions under high pressures V : pressure effects on thewalden products and hydration of Et4N+ and ClO4- ions inwater

Author(s) Nakahara, Masaru; Osugi, Jiro

Citation The Review of Physical Chemistry of Japan (1974), 43(2): 71-81

Issue Date 1974-01-31

URL http://hdl.handle.net/2433/46989

Right

Type Departmental Bulletin Paper

Textversion publisher

Kyoto University

The Review of Physical Chemistry of Japan Vol. 43 No. 2 (1973)

TaE REVIEW OF PHYSICAL CNE3IISTRY OF JAPAN, VOL, 43; NO. 2, 1973

IONIC SOLUTIONS UNDER HIGH PRESSURES V

Pressure Effects on The Walden Products and Hydration of

EtaN+ and CIOa Ions in Water

BY ~'fASARU N.4RAHAR.4 AND )IRO ~StiCI

The electrical conductivities of aqueous solutions at high pressures up to 5,000 atm have been measured in the concentration range from 10_4 to 10'sx for tetraethylammonium chloride, EtaNCI at 25 and 40'C and &or tetraethyl-ammonium perchlorate. EtINC10{ at 2~ C. The equivalent coaductances of [he electrolytes at i¢finite dilution have keen determined by means of the Onsager equation which was verified to be valid in the dilute solutions at high pressures in the previous papersl•r}. The limiting equfvalent conductances determined at high pressures were separated into the single-ion o¢es o¢ the basis of the same assumption as used in the previous paper~l. Although the limiting equi-valent conductance of EyN• has a maximum against pressure at 2YC ]ike other tetraalkylammonium ions, that of CIOa ,surprisingly and exceptionally, has no maximum even at 25'C where the viscosity of solvent water has a minimum at about 650 atms>. The Walden product of EtcN• decreases slightly with increasing pressure at 25'C and, probably, so at 40'C like that of ]SesN*. On [he other hand, the SValden product of CIO at 25'C dramatically decreases with increasing pressure. Thus, it is considered that the pressure dependence of the limiting equivalent conductance of the ion in water can not be explained merely in terms of such bulk properties of water as the viscosity and dielectric constant. These differences in the pressure coefficients of [he Walden products were ascribed to the differences between the density of the hydration shell and that of [he hull: water.

Introduction

Colladoo and S[urm41 are the first persons to. attempt to examine [he effect of pressure on the

electrical conductivities of electrolyte solutions, when it was not yet known what carries electricity

in solution. In Ig86, first of all, Finksl established that pressure (up to 500 atm) does decrease [he

electrical resistances of electrolyte solutions ; it was two years before the appearance of the Arrhenius

(Received September ]0, 1973) I) :1I. Nakahara, R. Shimizu and J. Osugi, This Journal, q2, 12 (1972) 2) b1. Nakahara, ibid., 42, 75 (1972) 3) J. B. Cappi, Ph. D, Thesis, London University (1964) 4) D. Colladoo and C. Sturm, Ann. Chim. Phys., 36, 23l (1827) 5) J• Fink, (Vied. Ann., 26, 481 (1865)


72 M. Nakahara and J• Osugi

theory for the behavior of electrolyte solutions. In the 1890's, Rontgen5l, Fanjungn and Tammannsl

first found a parallelism between the pressure dependence ofthe electrical conductivities of aqueous

solutions and that of the soheat fluidity measured by Cohensl. Strictly speaking, however, those early

works were not so much accurate but only phenomenological, even alter the eminent Debye-Hiickel

theorylo> for the strong electrolyte solution was developed in 1923. It seems to the authors that 5rst

great efforts to determine accurately the limiting equivalent conductances at high pressures were made

in the 1950's by Hamann and his coworkers in particular for the purpose of examining the pressure

effect on the ionization of weak electrolytes, In the 1960's, the accourately determined limiting equi-

valent conducfances at high pressures began to be analyzed in terms of the transition state theoryrs)

by Bmmmer and Hills%~• ts). Osugi, Shimizu and Takizawa161, and Adams and Laidler~%>, and also is

terms of the dielectric relaxation effect by Skinner and Fuosslgl and Cussler and Fuosst9~.

When we deal with a transport property in solution, [here is one fundamental question as to how

much the transport property might reflect the equilibrium property of ions in solution. In the case

of ionic conductance, however, there would be fairly good correspondence beriveen them for [he tol•

lowing reasons. The ions in solution are originally moving very rapidly in a random way colliding

with the solvent molecules or with each other, as well-known as Brownian motion. When an external

electric. field is applied to the system, the ions begin to move preferentially in the direction of the

applied Seld. At this time, if the external perturbation is so weak, as often in the conductance

measurement, that it may not disturb the internal field exerted by the ions themselves and polar

solvent molecules, the limiting ionic equivalent conductance would minutely reflect the ion-solvent

interaction in the equilibrium state. In consequence, the limiting ionic equivalent conductance could

be used as a useful probe to study ionic hydration. 9s a matter of fact, it was previously reported~f

that there are linear correlations between the hydration number calculated from the limiting ionic

equivalent conductance and the hydration enthalpy for the alkali metal ions and for the halogen ions

at normal pressure.

6) 7) 8) 9)

10) I1) 12) 13) 14) 13) lfi) 17) 18) 19) 20)

W. C. R"ontgea, A'achrichlen de> k. Gesellsch. zu Gdttingen, 509 (1893) I. Faajuag, Z. Pkys. Chenf., 14. 673 (1894) G. Tammana, ibid., 17, 725 (1895) E. Cohen, R4ed. Ann., 45, 666 (1892) P. Debye and E. Huckel, Phys. Z., 24, 185 (1923) S. D. Hamnn, "Physico-Chemical Effects of Pressure", Butternrorths, Loadoa (1957) S. D. Hamana aced N. Strauss, Trance Faraday Soc., 51, 1684 (1955) S. Glasstone, %. J. Laidler aced H. Eyring, "The Theory of Rate Processes", \fcGraw-Hill (1941) 5. B. Brummer and G. J• Hills, Trans. Faraday Soc., 37, 1816 (196t) S. B. Brummer and G. J. Hills, ibid., 57. 1823 (1961)

J. Osugi, K. Shimizu and H. Takizawa, This lonrnal, 34, 55 (1964) W. A. Adams and %. J. Laidler, Can. L Chen+, 46, 1989 (1966)

J. %. Skinner and R. \f. Fuoss, J. Phys. Chem,. 71, 4455 (1967) E. L. Cussler and R. M. Fuoss, ibid., 71, 4459 (1967) M. fiakahara, R. Shimizu and J. Osugi, Nippon Kagaku Zasslri (!. Chem. Soc, Japan, Pure Chem. Sec.), 92, 785 (1971)


Ionic Solutions under High Pressures V 73

Expermiental

Tetraethylammonium chloride, EC,NCI was obtained by using anion exchange resin from its

bromide which was first synthesized by the bienschutkin reaction. Et,NCI salt was three times

recrystaBized from its methanol solution by adding chilled ether, and dried in vacuum a[ about 50°C

for a week. Tetraethylammonium perchlorate was precipitated by adding excess amount of perchloric

acid to the aqueous solution of EgVBr*, recrystallized twice from its aqueous solution, and dried in

vacuum at room temperature for 3 days after heated up to 100-C for 2 hours with great care to avoid

explosion. The dilute sample solutions were prepazed from stock solutions just in the same way as

beforet.zU.

The high-pressure apparatus and the conductivity cell were already described elsewhere.

Results and Discussion

Determination of d°t Pa

The equivalent conductances..hPl of Et,NCI and EyNC10, in dilute aqueous solution a[ pres

sure P were determined, after the corrections for the solvent conductivity and changes in concentration

and cell constant with pressure had been made just in the same manner as the previous s[udytl.

Then. the equivalent conductances at infinite dilution at pressure P, ,frP> were obtained with the aid

of Onsager's equation for conductance,

[ha[ is,

1-rzt~C '

from which A°tl'~ of EyKC] at 25 and 40`C and EyNC10. at 2S'C were calculated and given in

Tables I^•3. The adequacy of this method to obtain d°tPa from Acl~ fn the dilute concentration

range would be supported by the approximate constancy of d`~ around their mean value within the

experimental error, which was already found in the previous study on \Ie,NCI and Bu,NCIz>. How•

ever, i[ was reported~•zz> that the direct graphicai extrapolation of the conductance data of Eq\CI to

infinite dilution with the aid of the theoretical limiting slope was not satisfactory exceptionally.

R'hen the conductances of EtaNCI shown in Table 1 are compared with those measured at a higher

concentration by Horne and Y'oungz+l, there are rather large discrepancies between them as found

* This salt was kindly supplied by Mr. T. Hori, Laboratory of Analytical Chemistry of our Depart ment.

21) ~I, Nakahara, K. Shimizu and J. Osugi, Tlais Journal, 40, 1 (1970) 22) A. B. Gancy and S. B. Stammer, J. Chern. Eng, Data, 16, 1763 (1968)

23) S. B. Stammer and A. B. Gancy, "Water and Aqueous Solutions", Chap. 19, Part I, ed. by R. A. Horne, Wiley-Interscience, New York ([912)

24) R. A, Horne and R. P. Young, L Phyr. Chem., 72, 1763 (1968)


74 .\l. Nakabara and J. Osugi

in the cases of Me,NCI and Bu,NClzl.

Table 1 A'CPl (ohm'l~cm2~equiv-1) of Eta NCI in Hs0 at 2SC

Sample*

Pressure, atmA B C D Average

1

500

1000

1,500

2,000

1,500

3,000

3,500

4,000

4,500

5,000

! 08.9

110.9

111.4

111.2

109.9

108.3

106.2

103.3

100.6

98.3

93_fi

108.9

110.6

1111

110.6

109a

107.6

101.3

102.9

100.3

97.6

950

108.8

110.7

Ill.4

110.9

109.7

107.8

105.7

103.1

100.3

97.7

94.9

(06.8

110.8

I1Ll

110.2

109.1

107.1

105.1

102.8

100.1

91.5

94.6

108.9

110.8

IIL3

110.7

109.5

107.7

105.6

103.0

100.4

97.6

95.0

* A: 3.866 x 10-~ n, B: 6.201.x 10-+ r, C: 8.536 x 10'1 s, D: 11.598 x 10'~ s at 1 a[m

Table 2 A'p•) (ohm lmmZ•equis~ 1) of EtgNC] in Hr0 a[ 40'C

~- _ Sample*

Pressure, atm-- -_

1

500

1,000

1,500

2,000

2, 500

3,000

3,500

4,000

4,300

5,000

A B C D Average

143.9

143.6

141.6

141.2

139.6

137.2

134.6

131.4

118.2

124.9

121.5

143.9

143.7

141,6

141.2

139.1

I3fi5

133.8

1305

127.2

123.6

120.1

143.8

143.7

142,6

1410

138.9

136.4

133.5

130.3

126.9

123.4

1 ] 9.9

143.9

143.6

142.5

I4L1

139.2

136.6

133.7

13o.a

127.0

123.4

119.8

143.9

143.7

142.6

141.1

139.2

136.6

133.9

130.7

127.3

123.8

120.4

* A: 3.847 x t0-~ ti, B: 5.992 x 10_a ~, C: 8.495 x IO-~ v, D : 11.542 x 10'~ a at 1 atm

Obtaining of 1°<rl from if°« The single-ion equivalent conductances at pressure P, ,)°tPl were calculated on the basis of the

same postulate used in Ref. (2) ; it was assumed that the Walden product of Bu~N' is approximately

independent of pressure. In the present calculation, the previous~> interpolations of the values of

water viscosity measured by Cappi3l have been corrected as shown in Table 4, because the interpo•

Iation from the direct plot of water viscosity, r!° against pressure was found to be less accurate than

23) Al. Nakabara, K. Shimizu and J. Osugi, TFis Journal, 40, 12 (1970)


Table

Ionic Solutions under High Pressures 4

3 d°tP7 (ohm ~•cmt•equiv r) of Eta1`rClO. in Hz0 at 25'C

1i

~'~

Pressure,

Sample*

atm~~A H C n Average

1

500

1,000

1;500

2,000

2,100

3,000

3.500

4,000

4,500

s.ooo

I 99.86

98.37

91.94

93.55

9D.45

87.34

84.40

81.11

7 i.89

14,80

71.93

99.95

95,71

9fi.49

93.82

90.69

87.4fi

84.38

81:11

i 8.02

74.99

72.08

99.82

98.61

96.27

93.41

90.41

87.20

84.11

80.90

77.85

74.82

71.96

99.95

98.89

96.43

93.60

90.53.

57.48

84.16

80.94

i 7.88

74.88

72.02

99.9

98.6

96.3

93.b

90.5

87.4

84.3

81.0

i7.9

14.9

i 2.0

k 4: 4.147 x IO_q N, B: 7.276 x 10-+ x-, C: 9.093 x 10-~ x, D: 10919 x 10-~ v

that from the plot of log >7U against pressure a[ the . high pressures due to the steep dependency of r`

upon pressure and the scarcity of the measured points (The corrected values of r` in Table 4 does not

make the curve of d-(I{CL)•r,` vr. pressure at 25-C cross [hat at 40`C; see Fig. 4 in Ref. (I)) The

obtained values of ),'cl~ at 25`C are summarized in Table i, where the values of A'<r.' of other ions so

far investigated are also given for comparison after the above correction has been made. In Table 5,

it is seen that the correction does not cause so large alteration in the values of x`l~ and the discussion

and conclusion in the previous paper might not be amended.

Table 4 The viscosity of wateq 7 (cP) at 25'C

(interpolated by plotting Cappf's data against pressure)

Pressure, atm Present Previous~7

1

500

l,ooo

lsoo

z.ooo

zsoo 3,000

3,500

4.000

4,500

s.ooo

0.8937

0.8865

0:8905

0.9033

0.9260

0.9532

0:9853

L0135

1.0589

1.0895

1.10.57

0.9266

0.9534

0.9709

1.0022

1.0392

1.0756

1.1163


76

Table

M. Nakahara and J. Osugi

5 2°tr) (ohm ~•cmz•equiv'~) of We ions in H2O at 25°C

_` ns Pressure. atm~

1

500 1,000

1,500

z,ooo

2,500

3,000

3,500 4,000

4,500

s,ooo

Buahr: Bu~N"" EtaN• Me4N• K* CI- CIO,

19.4

19.6

19.5

19.2

I s.7

18.2

1 i.6

17.1

16.4

15.9

151

19.4

19.6

19.5

19.2

1s.7

I8.2

17.9

17.3

16.7

16.1

us

32.5

32.9

32.5

31.8

30.9

30.0

29.0

27.8

26.8

26.0

24.8

44.7

45.0

44.4

43.8

42.8

41.6

40.3

38.9

37.6

36.1

34.5

73.5

74.7

74.6

74.0

73.0

71.9

70:1

68.4

66.6

64.9

62.4

i 6.4

77.9

i8.8

78.9

i S.6

77.7

76,6

75.2

73.6

71.8

70.2

67.4

65.7

63.8

61.8

59.6

57.4

55.3

53.2

51.1

48.9

47.2

~ Fram Ref . (2)

The postulate introduced to obtain the single-ion equivalent conductances at infinite dilution at

high pressures has been justified in Ref. (2) by comparing the calculated transference numbers of K*

in KCI,

it°<P~(KCl)

with those duectly measured up to 1.000 a[m at 25°C. In order to estimate [he values of d-<~ at 40'C,

it was additionally assumed Chat

Table 6 Walden products of the ions in H.,O at 40'C (ohm ~•cmr•equiv ~•cP)

-Ions Pressure, atm -~~

EtaN• Me~N' K• C1-

1

500

1,000

1,500

2,000

2500

3,000

3,500

4,000

4.500

5,000

za.i

z 7.a

27.9

27.8

27.i

27.5

27.5

27.5

27.2

27.2

27.0

41.1

39.6

40.2

40.9

39.8

39.8

39.8

39.8

39.i

39.5

39.1

63.0

63.7

64.4

65.4

66.2

67.1

67.9

68.7

69.4

70.0

70.3

b6.0

67.9

68.i

70.3

7 2.0

73.2

74.3

75.5

76.8

77.5

79.0


Ionic Solutions under High Pressures V i7

is nearly independent of temperature, because in our laboratory~l it has been recently shown that

r°cP%(K*) decreases by only 0.7% with the increase in temperature from 15 to 25~C or from 15 to

40`C both at 1,000 and at 1,500 atm. By using the values of c't~ at 25'C calculated from the ionic

equivalent conductance values in Table 5; d`tP~ (EtaNCI) in Table 2, d°Ctn (KCl) in Ref. (1), d-<~

(Me.NCI) in Ref. (2) and E`p> (K*) at 40-C in Ref. (27}, the single-ion values of the limiting equi~ valent conductances at 40°C a[ high pressures were obtained and used for the calculation of the R'a4

den Products in Table 6.

Pressure dependence of .i°<r~

The relative variation of the limiting equivalent conductances of the ions with pressure is shown

in Fig. 1. It is to be noted that the pressure dependence of J,'tP~ of tetraalkylammonium ions such

as Bu,V*, Et,N° and DIesN* are somewhat similar [o each other and. moreover, to that of the viscosity

of solvent water. On the other hand, the pressure dependence of d't~ of K*,. CI- and, above all,

C10. are quite different with each other. Furthermore, it is surprising that CIO,' ion has no maximum

conductance against pressure at 25'C, although all other ions so far studied hate a maximum con-

ductance against pressure at [he same temperature. These facts would suggest that the limiting ionic

equivalent conductance at high pressure can not be interpreted only by such a macroscopic property

of the solvent as aiscosit, in spite of the early finding and statement by RBntgea, Fanjung and Tam-

mann.

L1

0.9

0.8

o.io

/` C10,-

e,

Cl-

K•

i~ t,N•

u,N•

1 2 3 4

Pressure, 103 atm5

Fig. 1 d`CP)~,y°(U vs. pressure at 2s'C

Variation of the Walden product with pressure

In order to deduct the piessure influence on the macroscopic viscosity of water from that on the

ionic conductance, the Walden products, IV=d`1P)•n'<~ of the ions at 25`C are calculated by using

the values of d'tP' in Table 5 and r't~ is Table 4 and given in Table 7, and their relative variations

with pressureare shown in Fig. 2. There, we see that the pressure coefficient of the Walden product,

8W/r7P at 1 a[m and 2SC is positive, slightly negative and remazkably negative for G- and K* ions,

26) Y. lfatsubara. K. Shimizu and J. Osugi. This JonrnaI, 43, 24 (1973) 27) R. W. Allgood,.D. J. LeRoy and a. R. Gordoq J. CGenr. Phys.. g. 418 (1940)


78 \I. Nakahara and J. Osugi

Table 7 Walden products of the ions in Hz0 at 2SC

(ohm ~•cmZ~equiv r•cP)

Ious

Pressure, atm

I

500

1,000

1,500

2,000

2.500

3.000

3,500

4,000

4,500

5,000

EtrN• \fe4N• K• CI' CIOa

29.0

29.2

28.9

28.8

28.fi

28,6

28,fi

28.2

25.4

28.3

28.4

39.9

39.9

39.5

39.7

39.7

39.7

39.)

39.4

39.8

39.3

39.5

fi3.7

66.2

66.4

67.0

67.6

68.5

69.1

69.3

70.5

70,7

i 1.5

6.83

69.1

70.2

71.4

72.8

74.1

i 5.5

76.2

77.9

78.2

80.4

fi0.2

58.2

56.9

55.9

55.2

54.7

54.5

53.9

54.1

53.3

54.1

tetraalkylammonium ions and CIOa ion, respectively. Comparing Fig. 2 with Fig. 3~•~>, we notice

[hat 81~V18P at 25'C and I atm does not correlate with 8TJ'/17T at 1 atm 25'C for these ions. The

possible view-points for the interpretation of the pressure and temperature coe&cients of the ionic Walden product sre summarized in Table S, where al] the view-points but the first one are relevant

Table 8 Prediction o[ the sign of 8 [I%BP

Point of view Ref.

C)

D)

E)

P)

5)

Compression effect

Dielectric friction theory

Electrostrittioacheory

Pressure-induced dehydration

Structural change of water

i ~I

ao, n

18, 19

30

28

Sign of 8lY/BP

}

- . 0, +

[o ion-solvent interaction at any rate. Before we correlate the pressure coefficient of the ionic Walden

product with the ion-solvent interaction, we now consider the theoretical background of W or .i°.

Although in very dilute electrolyte solutions. +i has been successfully represented in some quantitative

forms by Oasager, Fuoss and others, no satisfactory theory for ionic conductance has been established

at the two extremes, at in5nite dilution and at high concentration. Owing to this undeveloped stage

of the theory for i°, we could not make any completely quantitative explanation of the pressure

28) R. L. Bay and D. F. Evans, !. Phyr. Chen+., 70, 2321 (1966) 29) R. A. Robinson and R H. Stokes, "Elettcolyte Solutions", Butterworths, London (1957)

30) R. A. Horne, "Advances in High Pressure Research", Vol. 2, Chap. 3, ed. by R. S. Bradley, Academic Press, London (1969)



s E

1.20e

1.1 ih a

CC

L10; v

K+

LOi

,Bu~N+1.00 o-o

n

o -~

0.9i TSe~N' Et~N+

C10,-0.90

0 1 2 3 4 5 Pressure, 103 atm

Fig. 2 iV(r')/NP) vs, pressure at 2SC

1.1

U

N j.0 ~F

V °' 0 .9 of

0.8

Bu,N'

EC,N•

Me.N*

K'CIO,

Fig. 3

0 20 •W 6D 80 100 Temperature,'C

Variation of the~i'alden products with temperature at 1 atm .t° of Bu,N*, E t,N• and Me,N• are cited from Ref. (28), and x' of R', CI- and CIOa irom Ref, (29).

coefficient of the ionic Walden product as yet. Then, we want to try some qualitative discussion by

using the modified~•211 Stokes equation,

CT re

where a, e, F, C, d` and r. are the ionic valence, protonic charge, Faraday constant, hydrodynamic

parameter being a fucction of r., solvent viscosity and effective radius of a hydrated ioa, respectively.

From Eq. (5) we hate

W-~.r-- GeF (0) When Eq. (6) is differentiated with respect to pressure, it follows that

8W __ air ~ t 1 a'C ~ ~ where the third factor in [be right-hand side has a positive value because oo^C/8r. is positive~•ul.

Then, it may be approximated that water exists in the following two states, -

stateI (standard state) K stateII

water ~ water. (8)

(in the bulk) (in the hydration shell)

For the above equilibrium, we can write

K= ai ~n>nru (al = 1, to ¢ l), (D) where K is the equilibrium constant, a the activity of wateq h the hydration number of an ioa at

infinite dilution, m the concentration of the ion waich is arbitrarily very small, and rg the activity


50 LI. Nakaha:a and J. Osugi

coefficient of water in the state IL More than ten years ago, the kinetic aspect of the hydration of

ions was discussed by Samoilov3l•~3 especially from the view-point of energetics. A'ow, we attempt

to discuss the hydration equilibrium in terms bf density. By dffierentiatiag the logarithmic form of Eq. (9) with respect to pressure, neglecting the pressure coefficient of Yg and Considering the basic

thermodynamic relztionship, we have

t7P h 8P RT (10)

where V°1 and V°q are the molal volumes of water in each state. Since rve can neglect the com-

pression effectll for such weakly hydrated (bulky monovalent) ions as RrN* and C1Og ,

sign of~ 8P ~ =sign of~ 8P ~. (Il) From Eqs. (7) and (10), we have

sign of( 8P ) =sign of (V°n-V'1), (12) if /~~0.

Eq. (12) means that the density of the hydration shell is larger than that of the bulk water if the

Walden product of Che ion has a negative pressure coefficient and vice ve>sn. As shown in Fig. 2,

o W(CIOs')/oP is strongly negative at L atm and comes to be nearly zero at ahout 5,000 atm. There-fore, rye could say the density of the water molecules in the vicinity of CIO. ion is higher than that

of the bulk water at the lox•er pressures and the difference becomes very small at about 5,000 atm.

This higher density around CIO9 ion could be accounted for by its breaking effect on the water

structure which would becomeweaker at high pressures because pressure would break down the water

structure. Furthermore, concerning the two types of molecular models~•~1 proposed for the orient-

ation of a water molecule with respect to an anion, Buckingham's one that seems to result in the

higher density of the hydration shell would be preferred especially for C1O~ ion. Judging from Fig.

2 and Table 6, oa the other hand, the hydration shells of the tetraalkylammonium ions have slightly

higher densities than that of the bulk water ; 81F{Btt~N*)/aP really becomes slightly negative, if the

directly measured transference number data~l are used for the estimation of the limiting equivalent

coaductances of the ions at high pressures instead of the postulate, d'<tl(BuaN*)•r~<3)=1.`tP~(Bu>N*)•

r`tP'. Although it is not sufficiently known in terms of both energy and density what kind of struc-ture of water is formed about alkyl chains, the above conclusion drawn from the pressure effect on the

\'r'alden products of Me.N*, EtcN* and BurN* ions seems to be conformed with the following voles

metric results :the negative contribution3s> to the partial molal volumes of the hydrophobic hydration

31) O. Ya. Samoilov, `structure of Aqueous Electrolytic Solutions and the Hydration of Ions", Chap. 3, Consultant Bureau, New York (1965)

32) 0. Ya. Samoilov, INrcussion Faraday Soc., 24, 141 (1957) 33) J. D. Bernal and R.H. Fowler, J. Chem. Plrys„ I, 535 (1933) 34) A. D. Buckingham, Discussion Pa>aday Soc.,.24, I51 (1957) 35) E J. ~Iillero, "Water and Aqueous Solutions", Chap. 13, ed. by R. A. Horne, Wiley-Interscience

(1972)

t The Review of Physical Chemistry of Japan Vol. 43 No. 2 (1973)


of the tetrnalkylammonium ions and the depressing effectss> of the tetrnalkylammonium ions on the

temperature of maximum density of water.

Laboratory of Physical Cheuaistry

Depar6neut of Chemistry

Faculty of Science

Xyoto University

Xyoto, 606

Japan

36) A. J. Darnell and J. Greyson, L Phys. Chene. 72, 302 (1968)

Ionic solutions under high pressures V : pressure effects...

Documents

Transcript of Ionic solutions under high pressures V : pressure effects...