Mem. Fac. Educ., Shimane Univ. (Nat Sci), Vol. 8, pp. 21-28, December 1974

STUDI ES ON

OF

THE DIELECTRIC

ORGANlC

PROPERTIES

SOLVENTS VIII.

A CORESPONDENCE BETWEEN THE REFRACTIVE DISPERSION AND THE SHIFT OF INFRA-RED ABSORPTION SPECTRA

Senseki TAKANO*

By

and Yukio KUROSAKI**

1. Introductiom.

Weak molecular interactions between diffe-

rent molecules in a liquid state give rise to

several breaking points on the curves of various physical properties vs composition at simple molar ratios. This fact has been examined in the previous papers for various kinds of physical properties such as dielectric

constant, 1,2) viscosity, 4,5) optical refractivity

3,6,7) and refractive dispersion. 8,9) Through

these investigations, it has been cleared out

that the observation of the polarizability of

a liquid mixture by the method of dielectric

measurements is most effective for the detec-

tion of the weak molecular interactions and

that of the refractive dispersion is more effective than that of simple refractivity

measurements In the present paper, the method of infra-

red absorption was introduced and examined

with related to the measurements of the refractive dispersion. However, especially in

the case of weak interactions, the shifts of

wave-number of the absorption spectra were very small, so it was very difficult to estimate

qualitatively the shifts of these spectra excep-

ting the pyridine-dioxane system

The very interesting result obtained in the

pyridine-dioxane system was that the curve of wave-number vs weight-fraction of dioxane

showed a breaking point and this fact showed

a remarkable difference from that of observed

* Laboratory of Chemistry, Faculty of tion, Shimane University, Matsue, Japan

** Yasugi Hlgh School, Yasug_ i City, Japan,

Educa-

in the ordinal solvent effects as noted by

Naofumi Oi in the case of benzene-phenol mixture. The curve expressed the relation between the composition which is ordinally expressed by the weight-fraction of j comp-

onent (wi) and the shift of wave-number of CH-extra-planer bending vibration of 700 to 750 cm~1 of pyridine molecule clearly showed

a breaking point at a fixed molar ratio, and

this composition of the mixture approximately

coincides with that of obtained from refractive

dispersion measurements

2. Experimentall Methods

Commercial reagents of special grade were used without further purification. But especi-

ally in pyridine, a special grade reagent was

refluxed over potassium hydroxide for a few days and then distilled. The middle fraction

was stored over barium oxide and redistilled

before use. The measurements of refractive index and the refractive dispersion were both

undertaken as same as reported in previous paper7). The theoretical values of refractive dispersion were calculated respectively accor-

ding to the following formula8)

d n I . 2 Kl n:! l d n

d~ (Kln~ + K2n~ ,3/2 d~.

K~2n{ . . . . . . . (1 ) d n

(Kln~ + K.2n~ 3/2 d~

Kl ?)vld2/ (.v~'Id2 + ~e'2d 1)

..(2,

K~ w~d~ /(wld2 + w2dl ~

22 Senseki TAKANO and Yukio KUROSAKI

The infra-red absorption spectra were obs-

erved by the use of Nihon Bunko IR-Spectr-ometer IRA-1. The identification of the spectra

and the measurements of wave-number were respectively undertaken by the comparison of these lines with those obtained from standard

polystyrene film

3. Optical Pro perties.

1) Cyclohexylamine-Dioxane System

Figs. 1, 2 and 3 respectively show the relati-

onships between the weight-fraction of dioxane

(wj) and the several optical properties such

as refractive index (n), refractive dispersion(Z)

and Abbe's number (L') at 25'C. Each of the

curves was illustrated downward in equall distances for avoiding the overlapping. In Fig. 2 a graph illustrated in the most down-

wards shows the relation between the calcu-lated values of Z according to the equation 1)

and the weight-fraction w.j at 25'C. As shown

in these curves, three breaking points are clearly recognized both in the refractive dispersion vs weight-fraction curves and Abbe's number vs weight-fraction curves

The mean values of w.j coresponding to these three breaking points in Fig. 2 were estimated to O . 32 for the first point, O . 46 for

the second point and 0.64 for the third point

respectively, and these values obtained from

Fig. 3 were almost identical to those of

obtained above. The coresponding molar

Z X 10

1. ･i 5

1. 4 4

1. i 3

1. 4 2

Cyclohexylam i ne( i ) -

(

Dioxane j)

ni~ -u'J, at 25 C 80

78

76

74

7! )

70

${ 8

t$U

65

Cyc lohexylamine( i)-

Dioxane( j)

Z2~. ' - u'j

Fig.

o o 2 0.4 o, 6 O. 8 1. O tL'j

1. The relationship between the refractrve index and the weight-fraction of droxane

wj, cur~res are illustrated downwards m regular order in situ.

o

Fig. 2.

o. 4 o. 8 o, 6 1.0 The relationship between the refractrve dispersion and the weight-fraction wj of

dioxane curves are illustrated downwards in regular order in situ.

STUDEIS ON THE DIELECTRIC PROPERTIES OF ORGANIC SOLVENTS VIII 23

v

6~o

61

60

59

58

'5:7

56

Abbe number of

Cyclohexylamine( i) -

Dioxane(j) at 25'C

o. 4 u'f o. 6 . o. 8 l, o

3. Abbe's number plot in relation to the we-ightfraction of dioxane zvJ, curves are illustrated downwards m regular order m situ.

:Z X 108

8~',

81

80

7~

78

77

7 6'

7-l::,

74

C~' yc I ()hexyl nm i n e ( i) -

Cyclohexanol( j)

Fig.

1 465

1. 4 6 3

l. 4 6 1

1 459

1457

1 455

1. 4 5 3

1 451

1. 4 4 9

Cyclohe)cylamine( i) -

Cyclohexanol( j)

e7;f-u'!' at 25'C

Fig.

0.8

o, 2 o, 6 u'j o. 4 l. o

4. The relationship between the refractive index and the wcught-fraction wj of cyclo-hexanol, curves are illustrated downwards in regular order m situ,

Fig. 5, o. 2 ~1'j , o. g o. 4 o. 6 1. o

The relationship between the refractrve drspersron and the welght--fraction of cyclohexanol ~vj, curves are illustrated downwards in regular order.

ratios were estimated to 2 : I for wj = 0.31,

1 : I for 0.42 and I : 2 for 0.65 respectively.

2) Cyclohexylamine-cyclohexanol System

Several examples of optical properties obs-

erved in this system were illustrated in Figs

4, 5 and 6. Fig. 4 shows the relationships between the refractive index (n) and the weight-fraction of cyclohexanol (wj) at 25'C.

Fig. 5 shows the relation between the refrac-

tive dispersion and the weightfraction of cyclohexanol (~'j) and Fig. 6 also shows the

same relationship for Abbe's number at the

same temperature. Likely to the cyclohexylamine-dioxane sys-

tem, three breaking points were also observed

in this system and the appearance of the breaking points was more distinct than that

of the former cases. The mean values of the coresponding three breaking points in Fig. 5 were respectively estimated for O . 30, O . 50 and

0.82, and these values estimated from Fig. 6

were also equall to those of obtained above.

24 Senseki TAKANO and Yukio KUROSAKI

59

30

nD

58

57

rT6

55 o

Al'rbe_ number of

Cyclol]exylnmine( i) -

(]'ycl(,he)cnnol(j) at 25'(_.:

{] '*1_' *" 'o, 8

o. ,~ u*, l' o

Fig. 6. Abbe's number plot in relation to the we-

lght-freaction of cyclohexanol wj, curves

are illustrated downwards in regular order in situ.

The coresponding molar ratios were calc-ulated respectively to 2 : I for wj = 0.30, I :

1 for 0.50 and I : 4 for 0.82.

3) Pyridine-Dioxane System

Some examples of optical properties of this

system were summarized in Figs 7, 8 and 9. Fig. 7 shows the relation between the refrectivity (n.) and the weight-fraction of

Dioxane (wj). at 300c Fig. 8 shows the same

relationship between the refractive dispersion

(Z) and the weight-fraction wj. Fig. 9 also

shows that of Abbe's number (~') and the weight-fraction. As clearly shown in Figs 8

and 9, the curves of refractive dispersion

and Abbe's number vs weight-fraction of

l. 4 9

1. 4 7

1. 4 5

l. 4 3

1. 4 O

Pyridine ( i) -

Di0~cane( j)

ni? -lrj at 30'C

0.2 0.4 0.6 0,8 l,o u' Fig. 7. The relatronship between the refractive

mdex and the weight-fraction of dioxane

w * curves are illustJated downwards in ',

regular order in situ.

dioxane respectively indicate us two clear breaking points at the compositions of wj =

0.35 and w.i = 0.70. The coresponding molar ratios at these breaking points were estimated to 2 : I at wj = 0.35 and I : 2 at

wj = 0.70 respectively. The details of these

data were already reported in the previous paper7).

4 . Infra-Red Absorption Spectra.

Figs 10, 11 and 12 respectively show the

infra-red absorption spectra in the lower ranges of wave-number in cyclohexylamine-dioxane, cyclohexylamine-cyclohexanol and pyridine-dioxane systems with the comparison

of the coresponding pure solvents. These data show us that a small amount of shift of

STUDEIS ON THE DIELECTRIC PROPERTIES OF ORGANlC SOLVENTS VIII 25

,'-1 X 10$

ZXl03

16

14

() It

lO

8

6

4

P)'ridine ( i') -

Dioxane( j)

Z)<lOs_u'f' at 30~C

Fig. 8.

0.4 0.6 0.8 l.o u~ The relationship between the refractrve dispersron and the wenght-fraction of dro-

xane wj, curves are illustrated downwards in regular order in situ.

3. l

2. 7

2.3

1. 9

15

Pyridine( i) -

Dioxane( j)

V~1 "IO u'j, at 30'C '+

Fig. 9. o:2 l,o u'j 0.4 0.6 o. 8

The relationshrp between Abbe's number and the welght-fraction of dioxane, wj, curves are ill. ustrated downwards in reg-

ular order in situ.

characteristic absorption can be recognized in

the range of 900 to 1200 cm~1 of the wave number which seems to be the absorption due

to CH-extra-planer bending vibration of the respective molecules. Especially in pyridine-

dioxane system, as illustrated in Figs. 12 and

13, a considerable amount of shift was observed in 700 and 749 cm~1 absorptions.

5. Discussiom

As already pointed out in the previous papers, the appearance of discontunity of the

gradient of the dispersion curve, Z vs weight-fraction w,f' suggests us that the formation of some kinds of molecular cluster

would be resulted in the liquid mixture. The

above mentioned inference has been demons-

trated by the fact that the observed values of

the considering physical properties of the mixture are, in the range of the two breaking

points or in the range of involving the points of pure solvents, completely coincided

with those of the calculated from the equations

which were theoretically introduced by assu-

ming that . the considering mixtures were completely ideal.

In another point of view, it would be presumably expected that if any structual changes of the liquid state may be resulted

at the composition of the above mentioned discontunious points, it would be resulted to

some changes in the mode of infra-red absorption spectrum at the coresponding discontinious points because the mode of vibration is exactly related to the mode of orientation of the nighbour molecules

26 Senseki TAKANO and Yukio KUROSAKI

1600'1500 'l400 1300 1200 1100. Iooo 900 800 700650

Fig. 10.

Fig. 13 shows one of the examples of the shifts of infra-red absorption spectra in pyri-

dine-dioxane mixture. The absorptions 0L 700

and 750 cm~1 of pyridine molecules were clearly transfered to the higher wave-number

side with the addition of dioxane molecules

Figs 14 and 15 respectively show the relation

between the shifts of wave-number and the weight-fraction of added dioxane. As clearly

shown in these figures, each of the curves

-i~ ~

~

{"..,! H

-, .. I*

- }-- t-

- t - ~

~ i7_ Q~I l ._ : l-

r$ s- -1 -

.i i : -r -

.- t･-

L. -'1 _.1_

-t- -6 o-!

fE = E = ~

,~

+ i f~ r

I':~ ~

L

-~-~t',-

.j - -l

I,:_~ _E ~ ~'iE L ~ i '- f 1: _~, i L-I , -LL~

I- t --

-L -

'~ Ilfls:T, ~ - ~ :11 .' l EL:4--+- - -

40 ~i: Ii- ~ir. ~ _ -i - ~ -r- --

fl ~]

':~T$ -t -

t Ti '~ - ~ _ CyclohexS Iam ine( i)

30~ ~

1- 8 L}

'I1- -

_i[ - l

i-- l] 71)･1 J

[[ 60 _ ~ :ill - ~

o

'IL .P

- 40~

- i:j=0.70:0.30 i -30-

- - -- - 8 O!-

70

6 O:~

~h:

5 --t.] -

-1 l~~

~ O~

- r - _ -- i * -

-.~' L ' , ~

- - ~~-30

20 [

Cyclohexanol(j) [ lO

4 ~F i - ~r~ -

+~

[~ ~ h

~

-10[ i ~: I I ~ ~- 7 ~

~ . l-

.~

- t'

' 61

J h

-~ -*., -t5

~E~ _ : _ _ ~ ~i~ L4 -

T ~-I~ li -

-f - - ~

: d4

7C 71

- _~' -~~:: i~~]~~~ _-':~ i 'I -] -1 ~*

. 60 6

-50 - 5l]-

r -

l~ - : '4~ l~ . - t' l]_

-~

()

l : j = O .35 : O .6S 2

~~ l

.1

~~1' ~ }

_ -!

6

60-

50 ~ O-

･~4c

L- -S-t-l ,

*~ 4 r_

1

-t-

3d 3

Dro~cane(j) ~

,

*~

J- ~-

~~E _ ~ l,: -r:

_L-:k

~-J

t~ l_

-o l- o I I,

180c~ 1700 1600 15nu 1400 130{.* 1200 1ln.rJ Iooo 900. 800

Fig. Il.

has a breaking point nearly at the weight-fraction of wj = 0.70, and this composition approximately coincides with that of observed

from the curves of refractive dispersion vs weight-fraction. In these figures, Iikely to the

infra-red absorption spectra which were obt-

ained by Naofumi Oi in'the benzene-phenol and benzene-anisole systems lo), the linear

relation between the shift of wave-number and the weight-fraction may be attributed to

STUDEIS ON THE DIELECTRIC PROPERTIES OF ORGANIC SOLVENTS VIII 27

17

11　1　　　　　11．一一一．・一エ…工二1二＝

■

≡．

『二二．

　　’　　’一　　　　　　■二　一　一　　r一一　　　一一一　　　　　　　　11　　　Di㈱鵬．・．一1三．I．

，一　　　　　　　■

’

‘ ■．1

…

■　　　’圭　’…一　11　　　■　　■

’

’　　　1■　　　　　一…

．’1　　一　　　　　　　　‘一1　10・一’…　　』　　　　　　　　　　　　　’　　　’1　　　1　　　　　　　　’11　　　　■11　　　　　　　　　　　　　　⊥　　　一　　　一　　一　　　　■　　■一50

一三、‘　　■■　　‘　　　　　■　＾‘’　’　・

■一4　　　’一

1柑一…ギp・・i巾・…三、二 一 一

■‘　一1　　　　－　　　　1■皿　　皿　＾…王

■

二：

2

＾

一

i7 町160450140013001｛200 00　00 90 001占65150 130Q

Fig. 12.

Fig.

800 750 .700 cEl~i

650

the ordinal solvent effect. Accordingly, the

presence of a breaking point on the curve of

infra-red absorption shift vs weight-fraction

in pyridine-dioxane system suggest us that the two different clusters in its structure would be formed at the diLferent sides of the

breaking points

100

13.

cal~ l

707

706

705

704

703

702

701

50

o

13 14 /~: P)'ridi ne

- - Pvridine -l- Dioxano

Left-wards shift of CH-extraplaner bendmg vibration of pyndine molecule

Pyridine( i) -

Dioxane( j)

()c¥(:_ H(*tl'~') - u'

Fig.

o

14.

02 0.4 0,8 u'j O.6 l. O

Relationship between the shift of IR-absorptron spectra m pyridine molecule and the welght-fraction of added dioxane

28

~~1

75 1

750

74

748

Senseki

Pyridine( i) -

Dioxane( j)

&c H(* ) ~wj

TAKANO and Yukio KUROSAKI

Literatures

l) S. Takano ; Studies on the Dielectric Properties

of Organic Solvents 1, (part 1). Dielectric

Drspersron m Ultra-low Frequency, Mem. Fac Educ. Shimane Univ., (Nat. Sci.), I (1967), pp 31-35.

2) S. Takano ; ibid, 1, (part 2). A New Equation

on the Drelectric Constant of Binary Organic

Mlxtures, Mem. Fac. Educ. Shimane Univ., (Nat. Sci), I (1967), pp. 31-35.

3) S. Takano ; ibid, II. A New Formula on the Refractive Index of Organic Binary Solvent System. Mem. Fac. Educ. Shimane Univ., 2 (1968), pp. 13-18.

0.4 Io ,,, 0.2 0.6 08 Frg. 15. Relationship between .the shift of IR-

absorptron spectra m pyndine molecule and the wei*･ht-fraction of added dioxane

Judging from these results of observations

on the refractive dispersion as illustrated in

Fig. 8 and 9, the stoichiometrical structure at

these breaking points can be denoted as [(Diox)2 (Pyrid)1]"" and that of the first break-

ing point can also be denoted as [(Diox)1 ( Pr yd )2]n'

Acoordingly, the structural change in the considering cluster at the either side of the

breaking point in Figs 14 and 15 may formally denoted as follows :

[(Diox)1(P7-yd )2]~ + 3nDiox-->

2[(Dlox]2( Pryd )ll~

The authors wish to thank Hiroko Inoue, Mikio Hara and Yukio Takeuchi, the graduate

course students of this laboratory, for the helpful assistance for this research.

4) S. Takano ; ibid, 111. A New Equation on the

Vlscoslty of Organic Binary Solvent Mixture,

Mem. Fac. Educ. Shimane Univ., (Nat. Sci), 3 (1970), pp. 1-9.

5) S. Takano ; ibid, IV. A Comparative Discussion

on the Identity of Various Viscosity Equations

wrth Respect to Takano Viscosity Equation, Mem. Fac. Educ. Shimane Univ., (Nat. Sci.), 4 (1970), pp. 25-38.

6) S. Takano ; ibid, V. The Experimental Certifi-

cation and the Comparative Discussion on the

Formulae of the Refractive Index for Poly-component Solvent Mixture, Mem. Fac. Educ Shimane Univ., (Nat. Sci.), 5 (1971), pp. 49-59

7) S. Takano ; ibid, VI. Molecular Complex For-mation in Water-Pyridine and Pyridine-Dioxane

Mlxtures, Mem. Fac. Educ, Shimane Univ., (Nat. Sci.), 6 (1972), pp. 71-82,

8) S, Takano and Y. Kurosaki ; ibid, V11, A The-

ory on the Disperslon of the Refractive Index

of Poly-Component Solvent Mixture System, Mem. Fac. Educ. Shimane Univ., (Nat. Sci.), 7 (1973), pp. 27-32.

9) S. Takano ; Optical Refractrvity of the Organic

Polycomponent Solvent Mixture. Analytical Instruments, 10, 8 (1972), pp. 36-46

10) Naofumi, Oi ; Effect of Solvent and Hydrogen

Bond on the Infra-red Absorption Spectra of Organic Compound. Yakugaku Zashi, 77 (1975), pp. 501-504. 504-506.