International Journal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 65

ISSN 2229-5518

Thermodynamic parameters of medicine with

Ethanol

Dr Sharmila Chaudhari

P.D.E.A.'s Baburaoji Gholap College,New Sanghvi,Pune -27,India

AbstractThe information related to the solute-solvent interaction has been carried out related to thermodynamic properties like activation en- ergy, conductivity, enthalpy entropy etc in the mixture of Ayurvedic Medicine-Dashmularishta and ethanol. Dielectric relaxation study of Dashmular- ishta used in gynaec problems has been carried out at 150C, 250C, 350C and 45 0C in the frequency range 10MHz to 20GHz for 11 different concentrations of the system. Time Domain Reflectometry (TDR) Technique in reflection mode has been used to measure Thermodynamic pa- rameters viz activation energy, conductivity, enthalpy entropy etc.Further, Fourier transforms and least square fit method has been used to obtain Thermodynamic parameters. W ith change in concentration and temperature, the systematic changes in Thermodynamic parameters are ob- served.

Index TermsTime Domain Reflectometry, Thermodynamic parameters ,Dielectric parameters,Dashmularishta,Activation energy

1. INTRODUCTION

—————————— ——————————
drive.
The temperature controller system with water bath and a
The dielectric relaxation study at microwave frequency gives
information about solute- solvent interaction and liquid struc-
ture of mixture. In this study, Ayurvedic medicine- Dashmu-

larishta has been used as solvent and ethanol as solute. The

Time Domain Reflectometry in reflection mode has been used
to obtain thermodynamics parameter. The objective of the pre-
sent paper is to report the dielectric relaxation study of above
system using TDR in the temperature range 150C to 450C.

2. EXPERIMENTAL MATERIAL

Dashmularishta (Shree BaidyanathAyurvedicBhavan Pvt. Ltd. Kolkata) and Methanol (ChangshuYangyuan Chemicals, Chi- na) were obtained commercially and used without further purification. The solutions were prepared at different volume percentage of Dashmularishta in Methanol at 11 concentra- tions.

thermostat has been used to maintain the constant tempera-
ture within the accuracy limit of ±1 0C. The sample cell is sur-
rounded by a heat insulating container through which the wa-
ter of constant temperature using temperature controller sys-
tem is circulated. The temperature at the cell is checked using
the thermometer.

3. DATA ANALYSIS

3.1Thermodynamic parameters

Kauzmann has given an extensive analysis of di- pole orientation as a rate phenomenon. Eyring14 consid- ered that dipole orientation involves passage over a po- tential energy barrier with a certain probability of jump- ing from one orientation to another. He obtained the po- larization P(t), as a function of time as

2.1Apparatus

The Thermodynamic parameters were obtained by using the
Time Domain Reflectometry method. The Hewlett Packard

P(t ) = P0

e ko t

(1)
HP54750 sampling oscilloscope with HP 54754A TDR plug in-
module has been used. A fast rising step voltage pulse of
about 200 mV amplitude and 43.8486 ns rise time with repeti-
tion frequency of 12.4 GHz is generated and is propagated
through a coaxial transmission line. The sample is placed at
the end of the coaxial transmission line in a standard Military
where, P0 is orientation polarization at t = 0;
k0 is the rate constant for the activation of dipole,
i.e. mean number of jumps made by a dipole in unit
time.
When t is such that k0 t = 1, P(t) must have decayed to
P0 /e. This value of t is a relaxation time, which may be
application (SMA) coaxial cell. The SMA cell used for this
defined as

τ =1 / k 0 . (2)

work had 3.5 mm outer diameter and 1.33 mm effective pin
length. The step pulse generated by tunnel diode and the
pulse which is reflected from the sample cell were sampled by
a sampling oscilloscope in the time window of 1.3 ns. The re-
flected pulse without sample R1 (t) and with sample Rx (t) av-
eraged 64 times and digitized with 1024 points in oscilloscope
memory and transferred to PC through a 1.44 floppy diskette
The process of molecular orientation requires an
activation energy sufficient to overcome the energy barrier
separating the two mean equilibrium positions. The num-
ber of times such a rotation will occur per second is giv-
en by the rate expression -

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International JourknTal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 66

IkSS0N=22129/-τ55=18

h

e −∆F / RT

(3)
lectric loss ε" , however, is a parameter which describes the motion of the charge i.e. conduction. Certain thermo- dynamicss are found to display conduction because of
where h is Plank's constant;
charge transport i.e. ionic conduction in electrolytes. This

∆F

relaxation.
is molar free energy of activation for dipole
conduction normally be described by a volume conductiv-
ity σ (mho/m). It is σadditive to dielectric loss, ε" , so that-
Since

∆F = ∆H − T∆S , (3.a)

ε" = ε"dielectric + ωε

(6)

τ = h kT

e H / RT

e − ∆S / R

(4)

The frequency variation of thermodynamics loss is given by
where

∆H is the enthalpy(heat) of activation for dipole - ( )

relaxation and

ε = ε s ε ωτ

tion.

∆S is the entropy of activation for dipole relaxa-

"

1 + ω 2τ 2

The entropy of activation

∆S may be calculated since

∆F is now known from eq. (3.a), and ∆H

is obtained = σ
from the slope of the curve for
1/T.
Eq. (4) can be rewritten as -

ln (τT) plotted against

so that -

ε 0 ω

(ε − ε )ω2 τ ε

σ = s ∞ 0

ln (τT) = ∆H + A RT

(5)

1+ ω2 τ 2

(7)

If σ is conduc(tivity at hi)gh frequency given by -

 h 

 ∆S 

σ =

ε s − ε

/ τ , we obtain -

A = ln 


 −  

where

 k 

 R 

σ ω2 τ 2

σ =

In eq. (4),

∆H / R , is the slope of

ln (τT)

v/s

1 + ω2 τ 2

1/T. If

∆H and

∆S are independent of temperature, then

plot of

ln (τT)

v/s 1/T is linear. The slope

∆H / R gives

(8)
the height of potential barrier. Differentiating eq. (3.a)
gives -
This equation describes the elevation of dielectric
conductivity from its zero value at zero frequency to a
value σ
at infinite frequency. The form of this elevation

H =

d [ln (τT )]

R

d [1 / T ]

RT

(6)
is similar to the form of the fall of the real part of the thermodynamics constant. If a static conductivity term σs is added, we get -
Thermodynamic properties may be used to access the dipole under the influence of applied field. The acti-

(σ σ s

)ω 2 τ 2

vation energy for every compound increases as the tem- perature increases, whereas the relaxation time decreases. This may be due to decreased viscosity of medium . With

σ = σ s

+

1 + ω 2 τ 2

(9)
increase in temperature the thermal agitation increases and dipole requires more energy in order to attain the equilibrium with the applied field. The molar free energy of activation is greater than the molar enthalpy of activa- tion, which results into negative values of enthalpy. This indicates that the activated state is more ordered than the normal state, which is true as in the activated state, and the dipoles try to align with the applied field.
Experiments designed to measure high frequency conductivity for bio-molecular solutions, confirms this re- lationship.

ε* =

Dispersion in conductivity
The complex thermodynamics constant,

ε' − i ε" , which is dimensionless quantity. The die-

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International Journal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 67

ISSN 2229-5518

Punarnavarishta ε' Punarnavarishta ε" Methanol ε'

80 Methanol ε"

70

60

50

40

30

20

10

0

ture

0.01 0.1 1 10

Frequency (GHz)


Figure.A: Corrected data for Dashmularishta + Methanol mixture at 350

40 Punarnavarishta

Methanol

35

30

25

20

15

10

5

0

0 10 20 30 40 50 60 70 80

ε'

Figure.B: Cole –Cole plot for Dashmularishta + Methanol.

1.0

0.9

0.8

0.7

0.6

Ideal

150C

250C

350C

450C

0.5

0.4

0.3

0.2

0.1

0.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Vol. fraction of Ethanol



Figure C : Variation of Bruggeman factor

0.24

0.22

0.20

0.18

0.16

0.14

0.12

0.10

0.08

0.06

0.04

0.02

0.00

-0.02

15oC

25oC

35oC

45oC

0 20 40 60 80 100

Volume Fraction of Ethanol

Figure D:Variation for Dashmularishta for vol

Table1.1: Bruggeman factor for Ashokarishta-Ethanol mix-

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ISSN 2229-5518

Table:1.2 Activation Enthalpy and Entropy of Dashmular- ishta –Ethanol

22 150C

250C

20 350C

450C

18

16

14

12

0.0 0.2 0.4 0.6 0.8 1.0

Volume fraction of Ethanol


Figure G: Variation of free energy of activation for
Dashmularishta + Ethanol

18

-16.5 100 % Ethanol

50 % Ethanol + 50 % Dash.

16 100 % Dashmularishta

-17.0

14

-17.5

12

-18.0

10

8

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Vol. fraction of Ethanol

-18.5

-19.0

3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50

1000/T

Figure E: Variation of Enthalpy for Dashmularishta + Ethanol

0.000 S

-0.002


Figure H:Arrehenius plot for Dashmularishta+Ethanol

-0.004

-0.006

-0.008

-0.010

-0.012

-0.014

-0.016

-0.018

-0.020

0.0 0.2 0.4 0.6 0.8 1.0

Volume fraction of Ethanol


Figure F: Variation of entropy for Dashmularishta+Entropy

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ISSN 2229-5518

4.CONCLUSIONS

Table : Summary of results for Dashmularista + Ethanol

2. M. T. Hosamani, R. H. Fattepur, D. K. Deshpande and
S. C. Mehrotra, J.Chem.soc. Faraday Trans91 (4) (1995)
623.
3. C. E. Shannon, Proc.IRE, 37 (1949)10.
4. R. H. Cole, J. G. Berbarian,S. Mashimo, G. Chryssikos,
A. Burns and E. Tombari, J.Appl.Phys.,66 (1989) 793.
5. P. Debye, polar molecules, Chemical catlog, New York
(1929)
6. P.R. Bevington, Data reduction and error analysis for the physical sciences,Mc-Graw Hill, New York (1969)
7. U. R. Lahane ,Structural Molecular Study of Ayurve- dic Medicines Using Dielectric Relaxation Tech.- Ph.D. Thesis ,Feb.(2003)
Bruggeman factor is used as first evidence of molecular interaction .This formula states the static permittivity ofthe mixtures which are related to volume fraction. The realationship between Bruggeman factor and V shows devaition which indicates molecular interact ion and can be observed practically. The values of Bruggeman factor shows repulsive force,attractive force and ideal situations.
Activation energy shows the dynamics of solute-solvent interaction,rotation of effective dipoles,etc.The activation en- ergy for every compound increases as the temperature in- creases,whereas the relaxation time decreases. This is due to decreased viscosity of the medium,which also indicates the activated state is more ordered than the normal one ,as the dipoles try to align with the applied field. The dielectric loss is a parameter which describes the motion of charge,that is conductivity.
Certain dilelectrics are found to display conduction due to charge tranfer,i.e. volume conductivity.

REFERENCES

1. A.C. Kumbharkhane, S. M. Puranic and S. C. Mehro- tra, J. Solution Chemistry20 (1991)12.

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