82505252 dielectric-spectroscopic-studies-on-cyclohexanone-and-2

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DIELECTRIC SPECTROSCOPIC STUDIES ON CYCLOHEXANONE AND 1,4–DIOXANE

*B.Thapa, † P. Bhattarai and B. Pokhrel

*Central Department of Physics, University Campus, Tribhuvan University, Kirtipur, Kathmandu, Nepal† Department of Physics, Padmakanya Campus, Bagbazar, Kathmandu, Nepal

Department of Physics, Institute of Engineering, Pulchowk, Lalitpur, Nepal

Key Words: Condensed Matter/Organic Liquids/Dielectric Property

The variation of dielectric constant of cyclohexanone (C6H10O) with the frequency from 42 Hz to 2 MHz and that of 1,4–dioxane (C4H8O2) from 42 Hz to 0.5 MHz were studied at a constant temperature of 250 C (298 K) by using HIOKI – HiTESTER (3532-50). The dependency of dielectric constant of binary mixture of these liquids with the concentration of cyclohexanone was also observed. The experimental data and literature data were used to test the theories of mixture of dielectric constant proposed by Lichtenecker – Rother, L. Landau and E. Lifshitz, Beer and Looyenga.



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INTRODUCTIONThe study of dielectric properties of liquid dielectrics provides the information about the structure, rotation and orientation of the molecules of liquids [1-2]. Several investigations have been made on dielectric studies for liquid dielectrics. Prasai et al. [3] and Yoshizaki et al. [4] studied the dielectric properties for polymer/solvent binary systems. The static dielectric constant (ε) for cyclohexanone and triethylamine mixture was investigated by Ratkovics and Parragi [5]. Likewise, Sudo et al. [6] examined the dielectric properties of ethyleneglycol–1,4-dioxane mixtures in the frequency range from 100 MHz to 30 GHz at 250 C using time domain reflectometry (TDR) mathod. The same method was implemented by Kumbharkhane and Shinde [7] to study the structural behavior of alcohol–1,4-dioxane through dielectric properties in the frequency range 10 MHz to 20 GHz. Similarly, various researches were made on the dielectric studies for liquid dielectrics [8-10].

Previously, Sharma et al. [11] reported the dependencies of static dielectric constant on temperature for liquid dielectrics using Schering Bridge. Kattel [12] also used the same methodology to study the similar properties for polystyrene-dichloromethane binary system. At present, we are interested to study the dielectric properties of liquid dielectrics at high frequencies rather than the static using HIOKI-HiTESTER (3532-50) (HH). Besides, there has been a pervasive curiosity to bring out the use of HH for the study on liquid dielectrics which was previously used for the study only on solid dielectrics, i.e. ceramics [13-16]. For this fulfillment, the major challenge was the construction of a parallel plate capacitor as a *, †To whom correspondence should be addressed. E-mail: [email protected], [email protected]; Phone: + 977-9841649286.◙ Presented on INTERNATIONAL CONFERENCE ON FRONTIERS OF PHYSICS 2009, Kathmandu, Nepal. And it is still to be reviewed.

sample holder for liquid dielectric. So we devised a glass-sealed parallel plate capacitor as a sample holder intending to have advantage over the dielectric cell used in Schering Bridge since this sample holder requires relatively lesser amount of dielectric than the dielectric cell. On over, the accessibility of the gang condenser, essential for the dielectric cell, has been rare in the market in Kathmandu. In

addition to the study on high frequency dependencies of ε, the present work also basically focuses on to find out the plausibility of HH for the study on liquid dielectrics using this sample holder.

So we have made the first attempt to use HH for the study on liquid dielectrics. In this work, we have opted cyclohexanone as a polar and 1,4-dioxane as a non-polar liquid dielectrics. We have observed the frequency dependencies of ε at constant temperature of 250 C (298 K) for each dielectric. In addition, we have also studied the dependency of ε on concentration of cyclohexanone (f1) for the binary system [(f1) cyclohexanone + (1- f1) 1,4–dioxane] at the constant frequency of 100 Hz and temperature of 250 C (298 K). The experimental data and literature data [17] are used to test the theories of mixture of dielectric constant.

EXPERIMENTAL SECTIONMaterials. The chemical substances employed were purchased from Glaxo India Limited (Mumbai, India), manufactured by Qualigens Fine Chemicals. The molecular weights and densities of the corresponding chemicals are listed in Table 1. Table 1. Characteristics of ‡cyclohexanone and 1,4-dioxane.(N: product number)

‡N N ‡Mw Mw‡ρ ρ

18265 18365 98.15 88.11 0.946 1.030

In the dielectric measurements of binary system, the concentration of cyclohexanone was gradually increased from 0 – 20%, 20 – 30%, and so on and finally to 100%.Theory of Mixture of Dielectric Constant. The theories of mixture of dielectric constant [1] under investigation are given by the relationships as:

Landau-LifshitzLL : εm1/3= f1 ε1

1/3 + (1- f1) ε2

1/3, BeerB: εm

1/2= f1 ε11/2 + (1- f1)

ε21/2,

Lichtenecker-RotherLR: logεm= f1logε1+ (1- f1) logε2 and LooyengaL: εm= [(ε2

1/3 - ε11/3) (1-

f1) + ε11/3]3

Where, ε1: ε for cyclohexanone and ε2: ε for 1,4-dioxane.

Apparatus and Procedure. Dielectric measurements were carried out in the frequency range from 42 Hz to 2 MHz at constant temperature of 250 C (298 K) with LCR HIOKI-HiTESTER (3532-50) (www.hioki.co.jp).

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The sample holder used with HH was especially designed for the measurements on liquid dielectrics. It is a glass-sealed parallel plate capacitor consisting two conical shaped parallel plate brass electrodes of diameter 1.8 cm each and thickness 3.3 cm as shown in Figure 1.

Figure 1. Experimetal Arrangement

The sample holder consists of a small aperture at the top of its middle part through which the desired amount of dielectric sample can be poured in it. A thermocouple, which is insulated, is dipped inside the sample to record its temperature. A DUAL CHANNEL THERMOMETER having standard type K (NiCr - NiAl) probe is used to measure the temperature at which the sample is kept. The two ends of the Brass electrodes are connected to HH impedance analyzer through coaxial cables of length 0.5 m. The HH is an impedance meter having a touch panel as the user interface that enables extremely easy operation. The test frequency can be set from 42 Hz to 5 MHz at high resolution of accuracy of ±0.008 %. The determination of dielectric constant of dielectrics involves measuring the capacitances of the capacitor with and without dielectrics. The straight line (■), y= -0.503x+17.482, clearly indicates the decrease inRESULTS AND DISCUSSIONDependency of dielectric constant of cyclohexanone and 1,4-dioxane with frequency.Table 2 presents the experimental data showing the frequency (f) dependence of dielectric constant () for cyclohexanone and

1,4-dioxane and Figure 2 represents the corresponding plot. Table 2. Capacitances measured at different frequencies.

cyclohexanonef/ Hz C/ pF ε42 569.88 16.5231x102 560.15 16.2415x102 551.15 15.981x103 538.73 15.625x103 519.01 15.0481x104 524.25 15.25x104 499.17 14.4731x105 478.17 13.8645x105 422.67 12.2551x106 413.85 11.9992x106 410.53 11.903

1,4-dioxane

42 72.532 2.1021x102 72.774 2.115x102 72.946 2.1141x103 73.112 2.1195x103 72.725 2.1081x104 71.833 2.0825x104 72.590 2.1041x105 70.172 2.0345x105 70.106 2.032

Figure 2. Plot of dielectric constant versus frequency. The scale on X-axis is logarithmic.[(■) cyclohexanone, (▲) 1,4-dioxane]

ε with the increase in f for the polar dielectric: cyclohexanone. This is due to the fact that the increase in frequency causes the rapid orientation of the permanent dipoles along the direction of the applied electric field forcing them to overcome the viscosity of the dielectric. Consequentlythis results the thermal agitation disturbing

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Table 3. eExperimental and lLiterature data of dielectric constant for the binary system.

f1eεm

lεmLL eεm

LL lεmB eεm

B lεmLR eεm

LR lεmL eεm

L

0 2.11 2.219 2.11 2.2189 2.11 2.219 2.11 2.2189 2.11000.2 4.008 3.713 3.5996 3.9767 3.8733 3.292 3.1736 3.7128 3.59970.3 5.301 4.662 4.5541 5.0466 4.9542 4.021 3.8921 4.6620 4.55410.4 6.989 5.761 5.6639 6.2437 6.1680 4.904 4.7732 5.7605 5.66390.5 7.991 7.019 6.9408 7.5682 7.5147 5.978 5.8539 7.0194 6.94080.6 9.775 8.449 8.3964 9.0199 8.9942 7.287 7.1793 8.4494 8.39640.7 10.732 10.062 10.043 10.599 10.607 8.842 8.8047 10.062 10.0430.8 12.477 11.867 11.891 12.305 12.352 10.85 10.799 11.867 11.8910.9 14.014 13.876 13.953 14.139 14.230 13.26 13.243 13.876 13.9530.95 15.01 14.960 15.068 15.103 15.219 14.51 14.666 14.960 15.0681 16.241 16.100 16.241 16.1 16.241 16.1 16.241 16.1 16.241

Figure 3. Plot to demonstrate the relation between experimental and literature results calculated from theories of mixture of dielectric constant. [(♦)eεm,(*)

lεmB, (○)

eεmB, (●)

lεmLL, (□)

lεmL, (■)

eεmLL, (∆)

eεmL, (○)

LεmLR, (+)

eεmLR]

the orienting tendency of the electronic and orientational polarization in the polar dielectric, thereby decreasing the capacitance of the capacitor [2]. Similar result has been mentioned for polar polymer – polyvinylacetate – by Tareev [1]. Unlike the polar dielectrics, in case of non-polar dielectrics, electric moment is produced due to an external applied electric field by the displacement of an elastically bound charge. The contribution of this induced moment to the polarization and hence to the dielectric does not significantly change over the broad frequency. The straight line (▲), y= -

0.0094x+2.1365, in Figure 2 shows the independency of ε on frequency for non-polar dielectric like 1,4-dioxane. This result is in favor of Tareev [1] who illustrated the variation of ε of solid non-polar dielectrics: polytetrafluoroethylene, polystyrene and polydichlorostyrene within the frequency range of 10 Hz to 1 GHz showing the independency of ε on frequency. He also presented the ε versus wavelength for liquid non-polar dielectrics: transformer oil and transformer oil with

20% of strongly polarized liquid, nitrobenzene (C6H5NO2), over 400 m. He has suggested the dipole polarization in the polar dielectric causes ε to remain invariable with the increase in ac voltage. Besides, Table 3 provides the experimental and literature data for the dependency of ε on f1

for binary system [(f1) cyclohexanone + (1- f1) 1,4–dioxane]. Figure 3 gives the comparison of experimental data of ε for the binary system [(f1) cyclohexanone + (1- f1) 1,4–dioxane] with that experimental and literature data calculated from the relations given by the theories of mixture. It is found that our present experimental result favors the Beer’s theory of mixture while the data for Landau-Lifshitz, Lichtenecker-Rother and Looyenga have marginal deviation from it.

Conclusions. It has been found the dependency of dielectric constant of cyclohexanone on the frequency that goes on diminishing as the frequency advances to higher values indicating the gradual loss of the tendency of electronic and orientational

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polarization which is one of the major characteristics of a polar dielectric. On the other hand, 1,4-dioxane has shown the independent behavior with the frequency variation confirming its non-polar characteristic. On the basis of the test of theories of mixture of dielectric constant for the binary system, it is concluded that our observation is in favor of Beer’s theory. Finally, we have successfully carried out this investigation concluding the plausibility of HH for the study on liquid dielectrics.

Acknowledgement. Appreciation is expressed to Professor D. R. Mishra for his constructive suggestions and department head of Central Department of Physics, Professor L. N. Jha, for his profound support. B. T. and P. B. wish to thank Institute of Engineering (IOE) for granting the opportunity to work in its laboratory providing HH. B. T. wishes to thank Mr. Nandalal Maharjan for his valuable contribution for the construction of sample holder.

REFERENCES[1] B. Tareev, 1975, PHYSICS OF

DIELECTRIC MATERIALS, Mir Publishers, Moscow, Russia.

[2] C. P. Smyth, 1955, DIELECTRIC BEHAVOIR AND STRUCTURE, McGRAW-HILL BOOK COMPANY, INC., New York, US.

[3] B. K. Prasai, P. Bhattarai and D. R. Mishra, Different Disordered-Systems, First Edition, October 2001, pp. 78 – 81.

[4] Kazuyuki Yoshizaki, Osamu Urakawa and Keiichiro Adachi, Dielectric Study of Concentration Fluctuation in Solutions of Polystyrene, Macromolecules, 2003, 36, 2349 – 2354.

[5] Ferenc Ratkovics and Maria Laszlo-Parragi, Fluid Phase Equilibria, Volume 17, Issue 1, 1984, pages 97 – 113.

[6] Seiichi Sudo, Noriaki Oshiki, Naoki Shinyashiki and Shin Yagihara, J. Phys. Chem. A, 2007, 111 (16), pp. 2993 – 2998.

[7] Ashok C. Kumbharkhane and M. N. Shinde, J. Phys. Chem. A, 2009, 113(38), pp. 10196 – 10201.

[8] Ramana Ch. V.V and Malakondaiah K., Journal of Indian Chemical Society Y. 2009, Vol. 86, No. 9, pages 979 – 981.

[9] V. Satheesh, M. Jeyaraj and J. Sobhanadri, Journal of Molecular Liquids, Volume 64, Issue 3, September 1995, pages 247 – 261.

[10] Gudrun Ahn-Ercan, Hartmut Krienke and Georg Schmeer, Journal of Molecular Liquids, Volume 129, Issues 1-2, 15 October 2006, pages 75 – 79.

[11] S. Sharma, M. Ojha and P. Bhattarai, The Physics of Disordered Materials, Edited by M.P. Saxena, N. S. Saxena and Deepika Bhandari, 1997, pp. 396 – 400.

[12] S. P. Kattel, 2005, An Experimental Study of Dielectric Constants of Polystyrene-Dichloromethane Binary Solution, M.Sc. Thesis, Central Department of Physics, Tribhuvan University, Kathmandu, Nepal.

[13] Nunu Lal Sahu, An Experimental Study on Phase Transition Behavior of the PbZrO3

Ceramics, M.Sc. Thesis, Central Department of Physics, Tribhuvan University, Kathmandu, Nepal.

[14] Mitra Mani Subedi, An Experimental Study on Electrical Behavior of (Pb1-XSnx) TiO3 (X = 0.10, 0.20, 0.30) Ceramics, M. Sc. Thesis, Central Department of Physics, Tribhuvan University, Kathmandu, Nepal.

[15] Nabin Chauhan, An Experimental Study on Electrical Behavior of [Pb1-x(Snx)] TiO3 (X= 0.05, 0.10, 0.15) Ceramics, M. Sc. Thesis, Central Department of Physics, Tribhuvan University, Kathmandu, Nepal.

[16] Medani Prasad Sangroula, An Experimental Study on Phase Transition Behavior of the [Pb1-x(Snx)] TiO3 (X= 0.02, 0.04, 0.06) Ceramics, M. Sc. Thesis, Central Department of Physics, Tribhuvan University, Kathmandu, Nepal.

[17] D. R. LIDE, 1995-1996, CRC HANDBOOK OF CHEMISTRY AND PHYSICS, 76th Edition, CRC Press Inc., Florida, US.

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82505252 dielectric-spectroscopic-studies-on-cyclohexanone-and-2

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