SALT EFFECT ON LIQUID LIQUID EQUILIBRIUM OF THE SYSTEM 298K: EXPERIMENTAL

SALT EFFECT ON LIQUID LIQUID EQUILIBRIUM OF THE SYSTEM 298K: EXPERIMENTAL
SALT EFFECT ON LIQUID LIQUID
EQUILIBRIUM OF THE SYSTEM
WATER + 1-BUTANOL + ACETONE AT
298K: EXPERIMENTAL
DETERMINATION
A Thesis Submitted
By
SITANSU PALEI
(Roll No. 10600015)
In partial fulfillment for the award of the Degree of
BACHELOR OF TECHNOLOGY
IN
CHEMICAL ENGINEERING
Under the esteemed guidance of
Dr. P RATH
Department of Chemical Engineering
National Institute of Technology Rourkela
2010
National Institute of Technology Rourkela
CERTIFICATE
This is to certify that the thesis entitled, “Salt effect on LLE of the system water + 1butanol + acetone at 298k: experimental determination” submitted by Sitansu Palei for
the requirements for the award of Bachelor of Technology in Chemical Engineering at
National Institute of Technology Rourkela, is an authentic work carried out by him under my
supervision and guidance.
To the best of my knowledge, the matter embodied in the seminar report has not been
submitted to any other University / Institute for the award of any Degree or Diploma.
Dr. P RATH
Date:
Professor
Department of Chemical Engineering
National Institute of Technology Rourkela
ii
ACKNOWLEDGEMENT
I would like to make my deepest appreciation and gratitude to Dr. P Rath for his valuable
guidance, constructive criticism and encouragement during every stage of this project. I am
totally indebted to his for providing me the right guidance to work on an emerging area of
chemical engineering. He was very supportive throughout the project and was always ready
to help.
Thanks to Dr. R K Singh and Dr. H M Jena for being uniformly excellent advisors. They
were always very helpful and provided broad ideas.
I owe a depth of gratitude to Prof. S. K. Agarwal, H.O.D, Department of Chemical
Engineering, for all the facilities provided during the course of my tenure.
Lastly I would like to thank my family members for their constant support, encouragement
and good wishes, without which this thesis wouldn’t have been possible.
Sitansu Palei
Date:
iii
ABSTRACT
The influence of a solid salt on VLE and LLE cannot be ignored because it
significantly changes the equilibrium composition. Liquid-Liquid Equilibrium is the
result of intermolecular forces which can significantly change due to salt addition
which introduces ionic forces , affecting the thermodynamic equilibrium . Aqueous
electrolyte liquid-liquid equilibrium is often related to extraction processes. In the present
work the salt effect on the system namely ‘1-Butanol+Water+Acetone’ has been studied with
various salts under varied concentration at 298K. The salt used in the above system are
NaCl,KCl with 5%,10% and 15% concentration. The solubility data and tie-line data are
taken experimentally at different salt concentration. The experimentally determined tie-line
data of this work have been correlated by Hand’s correlation.
KEYWORDS: Liquid–liquid equilibrium; Data; Salt effect; Experimental; Correlation
iv
CONTENTS
TITLE
PAGE NO.
Abstract
iv
List of Symbols
vii
List of figures
viii
List of Tables
xi
Chapter 1:
1.1 Introduction
1
1.2 Importance & Application
1
1.3 Objective of the present work
2
1.4 Liquid Liquid Equilibrium
2
1.5 Salt effect on LLE
3
1.6 Salting-in & Salting-out
4
2
5
Chapter 2:
Effect of salt on LLE
2.1 Salt effect on LLE (Table 1)
5
2.2 Systems studied under present work
11
3
12
Chapter 3:
Introduction for Experiment
3.1 Material used
12
3.2 Physical Properties of solvent used
12
3.3 Experimental set up
13
3.4 Procedure for solubility data for ternary liquid
14
System
3.5 Solubility data for salt containing ternary liquid
v
14
System
3.6 Measurement of equilibrium data for ternary
14
Liquid mixture with and without a salt
3.7 Method of analysis
15
4. Presentation of result
16
4.1 Empirical Correlation of salt effect on LLE
16
4.2 (a) All the figures
18 – 34
Chapter 4:
(b) All the plots
35 – 43
(c) All the Tables
44 – 54
4.3 Results and Discussion
55
Chapter 5:
Conclusion
56
References
57
vi
LIST OF SYMBOLS
A
Water
B
1 – Butanol
C
Acetone
XA
Mass fraction of Water
XB
Mass fraction of 1-Butanol
XC
Mass fraction of Acetone
XAA
Mass fraction of Water in Water layer
XAB
Mass fraction of Water in Butanol layer
XBA
Mass fraction of 1-Butanol in Water
XBB
Mass fraction of 1-Butanol in 1-Butanol layer
XCA
Mass fraction of Acetone in Water
XCB
Mass fraction of Acetone in Butanol layer
XS
Salt Percentage
a,b,c,d
Constants for Eisen-Joffe and Modified Campbell Equation.
Ln A, B Constants for Hand’s Plot
vii
LIST OF FIGURES
Fig No.
Contents
Page No.
1
Schematic diagram of LLE apparatus
18
2
Schematic diagram for evaporation of liquid mixture
19
3
Triangular Diagram
20
4
Plot of refractive index vs. Mass fraction of acetone
21
For no salt condition (Aqueous Phase)
5
Plot of refractive index vs. Mass fraction of acetone
21
For no salt condition (Organic Phase)
6
Plot of refractive index vs. Mass fraction of acetone
22
For 5% NaCl. (Aqueous Phase)
7
Plot of refractive index vs. Mass fraction of acetone
22
For 5% NaCl. (Organic Phase)
8
Plot of refractive index vs. Mass fraction of acetone
23
For 10% NaCl. (Aqueous Phase)
9
Plot of refractive index vs. Mass fraction of acetone
23
For 10% NaCl. (Organic Phase)
10
Plot of refractive index vs. Mass fraction of acetone
24
For 15% NaCl. (Aqueous Phase)
11
Plot of refractive index vs. Mass fraction of acetone
viii
24
For 15% NaCl. (Organic Phase)
12
Plot of refractive index vs. Mass fraction of acetone
25
For 5% KCl. (Aqueous Phase)
13
Plot of refractive index vs. Mass fraction of acetone
25
For 5% KCl. (Organic Phase)
14
Plot of refractive index vs. Mass fraction of acetone
26
For 10% KCl. (Aqueous Phase)
15
Plot of refractive index vs. Mass fraction of acetone
26
For 10% KCl. (Organic Phase)
16
Plot of refractive index vs. Mass fraction of acetone
27
For 15% KCl. (Aqueous Phase)
17
Plot of refractive index vs. Mass fraction of acetone
27
For 15% KCl. (Organic Phase)
18
Solubility curve for no salt condition
28
19
Solubility curve for 5% NaCl
29
20
Solubility curve for 10% NaCl
30
21
Solubility curve for 15% NaCl
31
22
Solubility curve for 5% KCl
32
23
Solubility curve for 10% KCl
33
24
Solubility curve for 15% KCl
34
25
Distribution curve for NaCl
35
26
Distribution curve for KCl
35
27
Campbell’s plot for NaCl
36
28
Campbell’s plot for KCl
36
29
Hand’s Plot for NaCl
37
ix
30
Hand’s Plot for KCl
37
31
Experimental vs. Calculated values of mass fraction of
38
Acetone (for NaCl) (Campbell Equation)
32
Experimental vs. Calculated values of mass fraction of
38
Acetone (for KCl) (Campbell Equation)
33
Experimental vs. Calculated values of mass fraction of
39
Acetone (for NaCl) (Eisen – Jeffe Equation)
34
Experimental vs. Calculated values of mass fraction of
39
Acetone (for KCl) (Eisen – Jeffe Equation)
35
Determination of Log A & B for NaCl (Campbell Equation)
40
36
Determination of Log A & B for KCl (Campbell Equation)
41
37
Determination of Log A & B for NaCl(Hand’s Equation)
42
38
Determination of Log A & B for KCl(Hand’s Equation)
x
43
LIST OF TABLES
Table No.
Contents
Page No.
1
List of Some Previous Investigation on Salt effect on LLE
5
2
List of system studied related present work
11
4.1.1
Solubility Data for no salt condition
44
4.1.2(i)
Solubility Data for 5% NaCl
44
4.1.2(ii)
Solubility Data for 10% NaCl
45
4.1.2(iii)
Solubility Data for 15% NaCl
45
4.1.3(i)
Solubility Data for 5% KCl
45
4.1.3(ii)
Solubility Data for 10% KCl
46
4.1.3(iii)
Solubility Data for 15% KCl
46
4.2.1
Equilibrium Data for No salt condition
47
4.2.2(i)
Equilibrium Data for 5% NaCl
47
4.2.2(ii)
Equilibrium Data for 10% NaCl
48
4.2.2(iii)
Equilibrium Data for 15% NaCl
48
4.2.3(i)
Equilibrium Data for 5% KCl
49
4.2.3(ii)
Equilibrium Data for 10% KCl
49
4.2.3(iii)
Equilibrium Data for 15% KCl
50
4.3.1
Constants Ln A & B in modified Campbell Equation
51
4.3.2
Constants Ln A & B in Hand’s Plot
51
4.4.1
Constants a, b, c and d in modified Campbell Equation
52
4.4.2
Constants a, b, c and d in Eisen – Joffe Equation
52
xi
4.5.1
Comparison between XCB – Experimental vs. XCB – Calculated
53
For NaCl.
4.5.2
Comparison between XCB – Experimental vs. XCB – Calculated
For KCl
xii
54
CHAPTER-1
1.1 INTRODUCTION
Aqueous solutions containing salts are of increasing importance and influence on separation
processes in chemical engineering. The electrolyte influence must be considered both in
process design and operation, because it can significantly change the equilibrium
composition. Aqueous liquid–liquid equilibrium is the results of intermolecular forces,
mainly of the hydrogen–bonding type; addition of a salt to such systems introduces ionic
forces that affect the thermodynamic equilibrium. When the mutual solubility decreases due
the salt addition, the size of the two–phase region increases, and this effect is called “saltingout”. In the opposite, when the solubility increases, the effect is called “salting-in”. The
salting–in effect can be used to remove organic compounds from water. [6]
Aqueous electrolyte liquid–liquid equilibrium is often related to extraction processes. For
instance, the ethyl acetate recovery from its mixture with ethanol involves an aqueous
extraction step in order to remove the ethanol. In this case, it is important to decrease the
mutual solubility’s of water and ester, improving the separation and yielding a dryer ester. [6]
The separation by solvent extraction becomes increasingly more difficult as the tie-line
becomes parallel to the solvent axis, as shown in solutropic solutions. By adding an adequate
salt, the mutual solubility of the mixture can be significantly changed, in order to modify the
slope of the tie-lines, even to the extent of eliminating the solutrope. [6]
The presence of an electrolyte in a solvent mixture can significantly change its equilibrium
composition. The concentration of a solvent component in a liquid phase of liquid-liquid
system increases if component is salted in and decreases if it is salted out of the liquid phase.
This salt effect has been advantageously used in solvent extraction. Separation by solvent
extraction becomes increasingly more difficult as the tie-lines become parallel to the solvent
axis as in the case of solutropic solution. By adding a suitable salt the tie-line of a LLE
mixture can be significantly changed, even to extent of eliminating the solutrope.
1.2 IMPORTANCE AND APPLICATION
The addition of an electrolyte to solvent mixtures changes the interaction among the various
solvent and solute molecules resulting in shifting their phase equilibrium even to the extent of
eliminating solutrope in liquid equilibrium. In an aqueous-organic solvent mixture, addition
1
of an electrolyte generally salts out the organic solvent molecules thus enriching the organic
phase with organic solvent component resulting in considerable reduction of the energy cost
incurred in the recovery and purification of the organic solvent.
Application of salting in effect: Salting in occurs when, for instance, a polar solvent is
added to an aqueous salt solution and is preferentially solvents the water and hence breaks the
hydration cages previously formed around the salt ions. The may be used to recover salts
from concentrated aqueous solution, and it is also important in biological separation process
such as purification of proteins, enzymes, nucleic acids and others.[2]
Application of Salting out effect:
1. Recovery of tightly hydrogen bonded organics from water such as formaldehyde,
formic acid and acetic acid by using ionic salt.
2. Biphasic mixtures containing of two immiscible phases are separated by use of salt
like ionic salt.
3. Mixture having non polar solvent +polar solvent + water, then salt is used to separate
the solution.
1.3 OBJECTIVE OF THE PRESENT WORK
In this project, a suitable correlation was suggested for application in industrial extraction
process involving water + solute + solvent + electrolyte systems. The correlation has to be
able to give an accurate description of liquid-liquid equilibrium that is important for solvent
extraction process. The present system comprises the following components.
Water+1-Butanol+Acetone
The main objective of the present work is to suggest a suitable correlation for the salt effect.
1.4 LIQUID-LIQUID EQUILIBRIUM
Triangular diagrams:
Liquid-liquid extraction involves the use of systems composed of at least three substances,
and in most cases all three components appear in both insoluble phases. Ternary systems are
often represented on equilateral or right triangular coordinates.
Triangular diagrams (fig. 3) are used for representing three component systems. Every
possible composition of the ternary mixture corresponds to a point in the diagram. Each
2
corner of the triangle represents a pure component and its designation is marked at this
corner. On the side opposite to this corner the mass fraction of this component is zero. In this
diagram the left vortex represent as diluents, right vertex as solvent and the top as solute. The
sides of the triangle represent the corresponding two-component system.
The sum of the vertical distances to the three sides from any point within the triangle is also
equal to 100 percent, from geometrical considerations.
If the quantities of diluents, solvent and solute present in a ternary mixture are such that two
phases exist, each phase is said to be mutually saturated. A plot of the compositions of the
two individual phases when in equilibrium with each other gives a mutual solubility curve.
Only ternary systems with miscibility gaps are suitable for extraction, and the boundary line
between the liquid single-phase region and two-phase region is particularly important. This
boundary line is called the binodial curve. Every point in the binodial curve is in equilibrium
with another binodial point. The lines, which connect points in equilibrium with one another,
are called tie-lines. All mixture, which correspond to a point on the tie line separate into two
phases.
1.5 SALT EFFECT ON LLE
Salt has a great effect on LLE. The addition of non-volatile solute to a solvent mixture
changes the interaction among the various solvent solutes molecules resulting in shifting their
phase equilibrium even to the extent of eliminating the solutrope in LLE. The salt mainly
affects the solubility of organic component in an aqueous-organic solvent mixture. Addition
of an electrolyte generally salts out the organic solvent molecules thus enriching the organic
in organic phase with organic solvent component resulting in considerable reduction of the
energy cost incurred in the recovery and purification of organic solvent. The distribution of
solute between two liquid phases mainly depends upon the concentration of electrolyte. The
electrolyte will remain in the phase in which it is most soluble and the other solute will be
transferred to the phase that it is poor in electrolyte. In other cases the addition of salt to a
solvent mixture can cause a phase split in a system that did not show demixing, this treatment
is sometimes used to enable separation by liquid extraction. Many liquid-liquid system
exhibits the solutropy and the phenomena in which the solute favours one phase at low solute
concentration other at higher solute concentration. A change in the behaviour of the solutropy
system is expected when salt is added in the system.
Selectivity, it is the process of removal of solute preferentially over water, which is
significantly affected by the salt present in the system. The selectivity, which is a ratio of
3
distribution coefficient of solute to that of water, is changed much more by salt addition then
is the distribution coefficient of the solute alone. The lower distribution coefficient of water
can be attributed to the association of water molecule in unextracted slating the aqueous
phase, which impedes a transfer of water to the organic phase. From practical point of view
resulting higher selectivity means a good separation.
1.6 SALTING OUT & SALTING IN
SALTING OUT:
Salting out can also is explained by the fact that when the ions are solvated, some of the
water becomes unavailable for solute which is then salted out from the aqueous phase. This
can be exploited to remove organic compounds from water. The term salting out is used since
if salt is added to a saturated solution of a non-electrolyte in water, the result is to bring the
non-electrolyte out of solution. [2]
SALTING IN:
Salting in occurs when, for instance, a polar solvent is added to an aqueous salt solution and
is preferentially solvents the water and hence breaks the hydration cages previously formed
around the salt ions. The may be used to recover salts from concentrated aqueous solution,
and it is also important in biological separation process such as purification of proteins,
enzymes, nucleic acids and others. [2]
4
CHAPTER - 2
LITERATURE REVIEW
2. EFFECT OF SALT ON LLE
A lot of authors have worked on liquid-liquid equilibrium system. But few of them worked
on the salt effect on LLE. It is observed that the use of salt has been proven advantageous. In
this review developments and trends are outlined with emphasis on existing correlation. The
literature relating to the industrial application with such a salt effect is described.
2.1 Salt effect on LLE
Table-1
Serial
Literature
System studied
Salt used
Results
A., Water+acetone+tolune
NaCl, KCl
Salting out effect
number
1
Hasseine
Meniai A H,
Water+cyclohexane+2-
is more prounced
Korichi
M, propanol
with
NaCl
salting
out Water+xylene+methanol
compared
to
effect of single
KCl,
to
salt on LLE,
difference
science direct,
hydration
Desalination
energies.
due
in
242 (2009) pp264-276 [2]
2
Bourayou N.,
Water+acetone
NaCl,
The addition of
Meniai A H,
Water+propanol
CaCl2
two salts has
Influence
of
shifted the
salt on liquid
systems from
phase equlibria
being totally
for
homogeneous to
totale
miscible
heterogeneous
organic
one. This has
compound with
great application
water, science
in phase
5
direct,
separation
Desalination
process.
185 (2005) pp473-481 [4]
3
Hu Mancheng, Water+1-propanol
KCl, CsCl
Wang Meixia, Water+2-propanol
inorganic
Li
and
Shu
ni,
salts
aliphatic
Jiang Yucheng,
alcohols on the
Guo
Haiyan,
LL
LLE
for
systems
region,
short,
in
the
different
Quaternary
4
Influences of the
salvation abilities
at
298.1K,
and
solubilities
science
of KCl, CsCl and
direct,fluid
the
phase
polarites of the
Equilibria 263
two
(2008) pp-109-
affected
114. [10]
results.
different
alcohols
the
Chen Jui Tang, Water+N-methyl-2-
NaCl, KCl, The lquid phase
Chen
CH3-COOK
Ming- pyrrolidone+1-pentanol
splitting for
Chung, salting
ternary system of
effect on LLE
water+N-methyl-
for the ternary
2-pyrrolidone+1-
system, science
pentanol can be
direct,
enhanced by
Fluid
Phase
adding the same
Equilibria
percentage of
266(2008), pp-
salts and the
1-7. [3]
influence follows
the order of
NaCl>KCl>KAc.
5
Santos G. R,
Water+Ethanol+1-
6
KBr
The addition of
d’Avila S.G,
Pentanol
bromide
Aznar M., salt
potassium
effect on LLE,
improves ethanol
Brazilian
extraction
by
journal of
means
1-
chemical
pentanol.
engineering,
improvement
Vol. 17,
result from salt
(2000),pp-721-
effect,
734. [11]
modifies
of
The
which
the
phase
equilibrium
the
of
mentioned
system,
increasing
the
distribution
coefficient
for
ethanol
and
selectivity of the
solvent.
6
KCl
Tan T.C.,
Water+1-propanol
Although methyl
Kannangare
Water+1-
ethyl ketone is a
k.K.D.D.S.,
propanol+methyl-ethyl-
reasonably good
Liquid-liquid
ketone
solvent
for
equilibrium of
solvent
a system in
extraction of 1-
prence of salt,
propanol from its
science direct,
aqueous mixture,
fluid phase
its
Equilibrium
effiency can be
190 (2001) pp-
further
179-189. [12]
considerably
extractive
enhanced
7
and
with
the addition of
KCl
into
the
solvent mixture.
Serial
Literature
System studied Salt used
Results
number
7
Solimo
Horacio
N., Water+propanic
Bonatti
Carlos
M., acid+1-butanol.
NaCl
The presence of
the salt
Zurita Jose L., de Doz
decreases the
Monica B. Gramajo,
solubility of the
salt
system,
effect
Fluid-
increasing the
Equilibria137
heterogeneous
LLE,Elsevier,
Phase
(1997)
on
pp-163-172.
zone. The
[13]
experimental
results lead to
the conclusion
that a saltingout effect is
present at all
studied
NaC1
concentrations,
increasing
8
for
higher
salt
concentrations.
8
R. Pedraza, F. Ruiz, Water+1M.D.
Saquete,
NaCl, KCl
V. butanol+2 salts
The liquid–
liquid tie lines
Gomis,Liquid-liquid-
obtained have
solid equilibrium for
been used to
quaternary
check the
system,Science direct,
accuracy of the
Fluid Phase Equilibria
predictions
216 (2004) 27–31. [14]
using the
electrolyte
NRTL model
(MNRTL). The
model is useful
for the
calculation
of the liquid–
liquid
equilibrium
data of
quaternary
systems using
parameters
obtained by
correlation of
some
Of the ternary
systems
that
constitutes it.
9
Tan T.C., Aravinth S., Water+acetic
NaCl, KCl
Both sodium
Salt effect on LLE, acid+1-butanol
and potassium
Elsevier, Fluid Phase
chloride
Equilibria
increased the
9
163(1999).243–257.
area of the two-
[15]
phase region
and decreased
the
Mutual
solubilities of 1butanol and
water. Both
marginally
decreased the
concentration of
1-butanol
and acetic acid
in the aqueous
phase while
significantly
increased their
concentrations
in the organic
Phase.
10
Vakili-Nezhaad
G.R., (water+propionic
Mohsen-Nia
acid+isopropyl
NaCl, KCl
The results
showed that
M.,Taghikhani
V., methyl ketone)
the electrolytes
Behpoor
M., (water+propionic
significantly
Aghahosseini
M., acid+isobutyl
affect the
Salting out effect of methyl ketone)
solubility of
salts on ternary LLE
Propionoic acid
data, Science direct, J.
In the organic
Chem.Thermodynamics
solvents used.
36 (2004) 341–348. [7]
The results also
showed
that the
distribution
10
coefficients for
Propionoic acid
and the
selectivity
of the organic
solvents in
extracting
Propionoic acid
increase in
the presence of
electrolytes
the
in
ternary
systems.
2.2 SYSTEM STUDIED UNDER PRESENT WORK
Literature
Santos
Fania
d’Avila
Saul
System Studied
S., Water+1Butanol+Acetone
G.,
Salt Used
NaCl, CH3-COONA
Aznar Martin, salt
effect
on
liquid-
liquid equilibrium of
water + 1-butanol +
acetone:
experimental
determination
and
thermodynamic
modeling,
direct,
science
fluid
equilibria
phase
187-188
(2001) 265-274.[6]
11
Remarks
Electrolyte LLE data
of quaternary
systems at 20 and
400c or
experimentally
determined by
chromatographic and
gravimetric analysis
.the effect of the salt
addition on the
original ternary
system was observed
by the increase of
two phase region
and the changes in
the slope of the
experimental tie
lines.
CHAPTER - 3
EXPERIMENTAL PROCEDURE AND SET UP
3. INTRODUCTION
The experimental measurement of liquid-liquid equilibrium must achieve two things.
•
It must locate the position of the solubility curve and
•
It must determine the composition of the coexisting phases, which locate the ends
of the tie lines.
In some cases these two objectives can be achieved in one measurement, and in other cases,
two sets of measurement are necessary. In the first case, for a ternary system mixtures of
three component are allowed to separate into its conjugate phases at equilibrium and the
equilibrate layers are analysed for their composition which will give the end points of the tie
lines. These end points when connected will give the binodial curve. This method is called
the method of analysis. The second method involves the estimation of binodial curve and the
tie lines in two stages, which is measured separately. [18, 21]
3.1 Materials Used:
Chemicals and salts used:
•
1-Butanol
•
Acetone
•
Water
•
Anhydrous NaCl (dried)
•
Anhydrous KCl (dried)
3.2 PHYSICAL PROPERTIES OF SOLVENT USED
Components
Acetone
Boling
point (0C)
56.53
Melting
point(K)
178
Molecular
Wt.(gm)
58.08
0.79
1-Butanol
117
183
74.12
0.81
Water
100
273
18.015
1
12
Density(Gm/ml)
3.3 EXPERIMENTAL SET UP
Experimental set up used for the determination of solubility data and tie line
determination.
Apparatus required:
•
Jacketed burette
•
LLE apparatus
•
Magnetic stir bar
•
Thermometer
•
Syringe
•
Refractometer
Jacketed Burette:
A Pyrex 50ml burette, provided with a jacket for water circulation from the thermostat
was used for titration in the determination of solubility data.
LLE apparatus:
It is jacketed cell water is flowing in the jacketed portion to maintain a constant temperature
for proper working of reaction. A thermometer is inserted in the inner cell to measure the
temperature. The prepared solution is fed into the inner cell, where it under goes proper
mixing with salt in presence of a magnetic stir bar.
Magnetic stir bar:
It is used for proper mixing of salt and prepared solution in the presence of magnetic field in
the inner cell. The stirring is continued for 2 to 3 hours.
Thermometer:
It is a mercury glass thermometer. It is used to measure the temperature of water in the
inner cell.
Syringe:
It is used to draw liquid phase sample from the opening at the top sampling port to avoid
cross contamination by other phase during the sampling process.
Refractometer:
It is used for the measurement of composition of phases at equilibrium.
13
3.4 PROCEDURE FOR SOLUBILITY DATA FOR TERNARY LIQUID
SYSTEM:
A known quantity of a heterogeneous mixture (water varying from 1 to 20ml and the
solvent varying from 20 to 1ml) was taken in a 100ml jacketed cell. Then the mixture was
titrated with solute (acetone) taken in a jacketed burette. Water from the constant
temperature bath was circulated through the jacket. The mixture was kept in constant
stirring condition. The point of miscibility was noted. The end point, in this case, the
disappearance of turbidity was noted. Then the refractive index of the mixture was
measured by refractometer. The mass fraction of each component was calculated and
tabulated. The above procedure was repeated for other specific mixture so as to cover
entire range of composition. [18, 21]
3.5 SOUBILITY DATA FOR SALT CONTAINING TERNARY LIQUID
SYSTEMS:
The solubility data of a salt containing ternary system was determined by adopting the
same experimental procedure used for salt free system, except that water was replaced
by aqueous salt solution. The concentration of aqueous salt solution was varied from
5% to 15% of salt by mass; these concentrations were below saturation with respect to
water. The solubility curve near the solvent rich region resulted in the precipitation of
salt, which marked the disappearance of turbidity. Hence a complete solubility curve
could not be obtained for the entire range of composition for the systems under this
study. [18, 21]
3.6 MEASUREMENT OF EQUILIBRIUM DATA FOR LIQUID MIXTURE
WITH AND WITHOUT A SALT:
A known heterogeneous ternary mixture was prepared by taking predetermined quantities
of the three components (10ml solvent + 10ml diluents (water or salt solution of known
concentration) + 1ml to 30ml of solute) in a 100ml jacketed cell. The mixture was
thoroughly agitated for two hours by magnetic stirrer. After agitation, the mixture was
allowed to stand for 2 hours to attain equilibrium. Two phases were found (i.e. reffinate &
extract). The individual layer are separated by syringe and weighed. Then the refractive
index of each layer was measured. In the case of dissolved salt each layer were boiled
separately and condensed to make salt free and the refractive index of each layer were
measured. The same technique was repeated for other known heterogeneous mixture. [18,
21]
14
3.7 METHOD OF ANALYSIS
There are many method used for analysis of equilibrium composition for ternary liquid
liquid equilibrium system. These are as follows:
1. Titration method
2. Refractive index method
3. Gas chromatograph method
4. Specific gravity method
Refractive index method:
Equilibrium data of LLE for three components system is obtained by measuring refractive
index of the solution using refractometer.
To find equilibrium data, known amount of three components corresponding to points within
the binodial curve contained in stopper flasks, were agitated in the constant temperature bath
over a period of 3 hours. At the end of this period the flasks were allowed to remain the bath
until the phases had completely separated. The samples of the separated layers were
withdrawn and their refractive indexes were measured. The composition of the equilibrium
layers were found by references to a large scale plot of refractive index against solute
concentration for saturated solution. In the case of dissolved salt each layer were boiled
separately and condensed to make it salt free and then refractive index of each layer was
measured.
15
CHAPTER - 4
4. PRESENTATION OF RESULTS
This section represents the result of experimental work done. The solubility data with and
without salt determined for above system are presented in table (4.1) as well as plotted in
figure. The figures represent the smoothed values of solubility composition. The equilibrium
tie line data are also presented in table (4.2). All salt containing data are reported on salt free
basis. The experimental tie line data under no salt condition were determined and presented
in their respective tables.
4.1EMPIRICAL CORRELATION OF SALT EFFECT ON LLE
The effects of salt on LLE of a ternary system have been widely studied. A lot of theories
have advanced to explain the complex effect. However, the mathematical characterization of
the salt effect has been semi quantitative at best, because of limitation of theories or
inadequacy of assumptions made in the derivation of those equations. Hand and Othmer
Tobias [16] have proposed equations to correlate tie line data of ternary liquid-liquid system
under no salt condition. Setchenow, Eisen and Joffe [17] have proposed semi empirical
models to correlate the tie line data of the ternary LLE under salt dissolved in the system.
Setchenow [25] has proposed the following empirical equation for the salt effect on the
distribution of solute between the relatively insatiable systems.
Ln(X0CA/XCA) = KS XSaA
------------ (4.1)
Where, KS is a salt parameter.
According to Long and McDevit [21] have suggested the following equation which was
derived on the basis of thermodynamic consideration
Ln (X0CA/XCA) = KS XSaA + KC(XCA – X0CA) ---------- (4.2)
16
Hand’s equation [18, 20, and 24] for no salt condition is
Ln(XCB/XBB) = B Ln(XCA/XAA) + Ln A --------------- (4.3)
Eisen-Joffe [17, 20, and 24] equation is best on the adaptation of Hand’s equation to system
containing dissolved salts. In their model they have fitted Hand’s constants Ln A and B in the
following relations in the presence of salt, as a linear function of salt concentration.
Ln A = a + b XS and B = c + d XS -------------------- (4.4)
With the above relationships they have modified Hand’s correlation into the following
expression to suit the salt system. [20]
Ln (XCB/XBB) = (a + b XS) + (c + d XS) Ln (XCA/XAA) ------ (4.5)
Where a, b, c and d are constants which depend on the nature of the system, nature of the salt
and temperature, but are independent of salt concentration.
Recently Campbell [18, 23] proposed a correlation of ternary liquid system containing
dissolved salts. The equation is as follows.
Ln (XCB) = (a + b XS) + (c + d XS) Ln (XCA) ------------------ (4.6)
The present system is correlated by using Eisen - Joffe equation and Campbell equation for
different salt concentration.
17
Fig.
1
SCHEMATIC DIAGRAM OF
APPARATUS [9]
(1) Thermostatic water inlet
(2) Thermostatic water outlet
(3) Stir bar
(4) Sampling port for upper phase (LII)
(5) Sampling port for lower phase (LI)
(6) Thermometer
18
LIQUID-LIQUID
EQUILIBRIUM
Fig. 2 SCHEMATIC DIAGRAM FOR EVAPORATION OF LIQUID MIXTURE
19
Fig. 3 Triangular Diagram
20
1.375
1.37
Refractive Index
1.365
1.36
1.355
1.35
1.345
1.34
1.335
1.33
0
5
10
15
Mass Fraction of Acetone (aqueous Phase) (No Salt)
20
Fig. 4 Mass Fraction vs. Refractive Index (Aqueous Phase) (No Salt)
1.384
Refractive Index
1.382
1.38
1.378
1.376
1.374
1.372
0
2
4
6
8
10
12
14
Mass Fraction of Acetone (Organic Phase) (No Salt)
Fig. 5 Mass Fraction vs. Refractive Index (Organic Phase) (No Salt)
21
1.375
Refractive Index
1.37
1.365
1.36
1.355
1.35
1.345
1.34
0
5
10
15
20
Mass fraction of Acetone (aqueous phase) (5% NaCl)
25
Fig. 6 Mass Fraction vs. Refractive Index (Aqueous Phase) (5% NaCl)
1.395
Refractive Index
1.39
1.385
1.38
1.375
1.37
0
5
10
15
Mass fraction of Acetone (organic phase)
(5% NaCl)
20
Fig. 7 Mass Fraction vs. Refractive Index (Organic Phase) (5% NaCl)
22
Refractive Index
1.375
1.37
1.365
1.36
1.355
1.35
1.345
1.34
1.335
1.33
1.325
0
5
10
15
20
25
30
35
Mass fraction of Acetone (aqueous phase)
(10% NaCl)
Refractive Index
Fig. 8 Mass Fraction vs. Refractive Index (Aqueous Phase) (10% NaCl)
1.384
1.383
1.382
1.381
1.38
1.379
1.378
1.377
1.376
1.375
0
5
10
15
20
25
30
35
Mass fraction of Acetone (organic phase)
(10% NaCl)
Fig. 9 Mass Fraction vs. Refractive Index (Organic Phase) (10% NaCl)
23
1.365
Refractive Index
1.36
1.355
1.35
1.345
1.34
1.335
1.33
0
5
10
15
20
25
30
Mass fraction of Acetone (aqueous phase)
(15% NaCl)
35
40
Fig. 10 Mass Fraction vs. Refractive Index (Aqueous Phase) (15% NaCl)
1.388
Refractive Index
1.386
1.384
1.382
1.38
1.378
1.376
1.374
1.372
0
5
10
15
20
25
Mass fraction of Acetone (organic phase)
(15% NaCl)
Fig. 11 Mass Fraction vs. Refractive Index (Organic Phase) (15% NaCl)
24
Refractive Index
1.385
1.38
1.375
1.37
1.365
1.36
1.355
1.35
1.345
1.34
0
5
10
15
20
25
30
35
Mass fraction of Acetone (aqueous phase)
(5% KCl)
Fig. 12 Mass Fraction vs. Refractive Index (Aqueous Phase) (5% KCl)
1.3895
Refractive Index
1.389
1.3885
1.388
1.3875
1.387
1.3865
0
5
10
15
20
25
Mass fraction of Acetone (organic phase)
(5% KCl)
30
Fig. 13 Mass Fraction vs. Refractive Index (Organic Phase) (5% KCl)
25
1.38
Refractive Index
1.375
1.37
1.365
1.36
1.355
1.35
1.345
1.34
0
5
10
15
20
25
30
Mass fraction of Acetone (aqueous phase)
(10% KCl)
35
Fig. 14 Mass Fraction vs. Refractive Index (Aqueous Phase) (10% KCl)
1.385
1.384
Refractive Index
1.383
1.382
1.381
1.38
1.379
1.378
1.377
1.376
0
5
10
15
20
25
30
Mass fraction of Acetone (organic phase)
(10% KCl)
Fig. 15 Mass Fraction vs. Refractive Index (Organic Phase) (10% KCl)
26
1.37
Refractive Index
1.365
1.36
1.355
1.35
1.345
1.34
1.335
1.33
0
5
10
15
20
25
30
Mass fraction of Acetone (aqueous phase)
(15% KCl)
35
40
Refractive Index
Fig. 16 Mass Fraction vs. Refractive Index (Aqueous Phase) (15% KCl)
1.39
1.388
1.386
1.384
1.382
1.38
1.378
1.376
1.374
1.372
1.37
0
5
10
15
20
Mass fraction of Acetone (organic phase)
(15% KCl)
25
Fig. 17 Mass Fraction vs. Refractive Index (Organic Phase) (15% KCl)
27
Fig. 18 Solubility curve for no salt
28
Fig. 19 Solubility curve for 5% NaCl
29
Fig. 20 Solubility curve for 10% NaCl
\
30
Fig. 21 Solubility Curve for 15% NaCl
31
Fig. 22 Solubility curve for 5% KCl
32
Fig. 23 Solubility Curve for 10% KCl
33
Fig. 24 Solubility Curve for 15% KCl
34
NaCl
0.45
0.4
0.35
XCB
0.3
0.25
No Salt
0.2
5% Salt
0.15
10% Salt
0.1
15% Salt
0.05
0
0
0.1
0.2
0.3
0.4
0.5
XCA
Fig. 25 DISTRIBUTION CURVE
KCl
0.45
XCB
0.4
0.35
0.3
0.25
No Salt
0.2
5% Salt
0.15
10% Salt
0.1
15% Salt
0.05
0
0
0.1
0.2
0.3
XCA
Fig. 26 DISTRIBUTION CURVE
35
0.4
0.5
NaCl
Ln(XCB)
100
No Salt
10
5% Salt
10% Salt
15% Salt
1
0.1
1
10
100
Ln(XCA)
Fig. 27 Campbell’s Plot
KCl
Ln(XCB)
100
No Salt
10
5% Salt
10% Salt
15% Salt
1
0.1
1
10
Ln(XCA)
Fig. 28 Campbell’s Plot
36
100
NaCl
Ln(XCB/XBB)
100
No Salt
10
5% Salt
10% Salt
15% Salt
1
0.1
1
10
100
Ln(XCA/XAA)
Fig. 29 Hand’s Plot
KCl
Ln(XCB/XBB)
100
No Salt
10
5% Salt
10% Salt
15% Salt
1
0.1
1
10
Ln(XCA/XAA)
Fig. 30 Hand’s Plot
37
100
Calculated Value.....>
NaCl
0.6
0.5
0.4
0.3
5% Salt
0.2
10% Salt
0.1
15% Salt
0
0
0.1
0.2
0.3
0.4
0.5
0.6
Experimental Value ..........>
(Campbell Equation)
Fig. 31 Experimental vs. Calculated values of mass fraction of acetone
(for NaCl)
KCl
Calculated Value.....>
0.6
0.5
0.4
0.3
5% Salt
0.2
10% Salt
0.1
15% Salt
0
0
0.1
0.2
0.3
0.4
0.5
0.6
Experimental Value ..........>
(Campbell Equation)
Fig. 32 Experimental vs. Calculated values of mass fraction of acetone
(for KCl)
38
NaCl
Calculated Value.....>
0.6
0.5
0.4
0.3
5% Salt
0.2
10% Salt
0.1
15% Salt
0
0
0.1
0.2
0.3
0.4
0.5
0.6
Experimental Value ..........>
(Eisen-Joffe Equqtiom)
Fig. 33 Experimental vs. Calculated values of mass fraction of acetone
(for NaCl)
Calculated Value.....>
KCl
0.6
0.5
0.4
0.3
0.2
5% Salt
0.1
10% Salt
0
15% Salt
0
0.1
0.2
0.3
0.4
0.5
0.6
Experimental Value ..........>
(Eisen-Joffe Equqtiom)
Fig. 34 Experimental vs. Calculated values of mass fraction of acetone
(for KCl)
39
5% NaCl
No Salt
1
1
0.1
0.01
1
0.1
1
Log(XCB)
0.01
Log(XCB)
0.001
0.1
0.1
0.01
0.01
y = 3.0335x + 0.0165
Log(XCA)
R² = 0.8588
Log(XCA)
15% NaCl
1
1
0.1
1
Log(XCB)
Log(XCB)
10% NaCl
y = 1.3544x + 0.0021
R² = 0.9957
0.1
1
0.1
Log(XCA) y = 0.8598x + 0.0475
Log(XCA)
R² = 0.9888
0.1
y = 0.956x - 0.1289
R² = 0.9751
Fig. 35 Determination of Log A & B for NaCl (Campbell Equation)
40
5% KCl
10% KCl
1
0.1
1
1
0.1
1
Log(XCB)
Log(XCB)
0.01
0.1
y
=
0.59x
+
0.1733
Log(XCA)
R² = 0.9818
Log(XCA)
0.1
y = 0.7948x + 0.0632
R² = 0.9743
15% KCl
Log(XCB)
1
0.1
1
0.1
Log(XCA)
y = 1x - 0.06
R² = 1
Fig. 36 Determination of Log A & B for KCl (Campbell Equation)
41
5% NaCl
Ln(XCB/XBB)
1
0.01
0.1
1
0.1
0.01
y = 1.448x - 0.0064
R² = 0.9901
Ln(XCA/XAA)
Ln(XCB/XBB)
10% NaCl
1
0.1
1
0.1
y = 0.8365x + 0.2445
R² = 0.8777
Ln(XCA/XAA)
Ln(XCB/XBB)
15% NaCl
1
0.1
1
0.1
Ln(XCA/XAA)
y = 0.557x - 0.0578
R² = 0.9113
Fig. 37 Determination of Log A & B for NaCl(Hand’s Equation)
42
No Salt
5% KCl
0.1
Ln(XCB/XBB)
0.01
Ln(XCB/XBB)
1
0.001
1
0.1
1
0.01
0.1
0.1
0.01
Ln(XCA/XAA)
y = 4.5726x + 0.0215
R² = 0.8824
Ln(XCA/XAA)
Ln(XCB/XBB)
Ln(XCB/XBB)
y = 1.2937x + 0.2324
R² = 0.9874
15% KCl
10% KCl
1
0.1
1
1
0.1
0.1
Ln(XCA/XAA)
1
Ln(XCA/XAA)
y = 1.1479x + 0.0808
R² = 0.9655
1
0.1
y = 0.7517x + 0.0016
R² = 0.9897
Fig. 38 Determination of Log A & B for KCl(Hand’s Equation)
43
TABLE – 4.1
SOLUBILITY DATA
(For All Systems)
System: Water + Acetone + 1-Butanol
Table 4.1.1
1. NO SALT
SL.No
XA
XB
XC
Refractive
Index
1
2
3
4
5
6
7
8
9
10
11
12
13
92.53
80.67
65.84
52.08
44.52
39.67
37.71
33.92
30.64
25.69
21.38
19.53
16.47
7.65
11.62
21.33
32.25
39.34
44.09
49.63
54.33
58.98
64.0
73.56
79.82
83.21
0
18.71
12.83
15.67
16.14
16.24
12.66
11.75
10.38
10.31
5.06
0.65
0.32
1.341
1.348
1.354
1.365
1.369
1.372
1.373
1.374
1.375
1.376
1.377
1.379
1.382
Table 4.1.2 (i)
2. SALT: SODIUM CHLORIDE (NaCl)
(i)
5% By Weight
SL. No
XA
XB
XC
Refractive
Index
1
2
3
4
5
6
7
8
9
10
11
12
13
93.65
85.24
69.01
53.56
44.35
40.19
35.85
30.35
28.88
21.0
15.33
9.94
8.45
6.65
10.83
21.3
30.99
37.63
41.33
44.93
50.82
54.98
63.33
72.55
82.86
88.25
0
4.03
9.69
15.45
18.02
18.48
19.22
18.83
16.14
15.67
12.12
7.20
3.3
1.343
1.350
1.360
1.366
1.368
1.370
1.371
1.372
1.373
1.374
1.376
1.386
1.389
44
Table 4.1.2 (ii)
(ii)
10% By Weight
SL.No
XA
XB
XC
Refractive
Index
1
2
3
4
5
6
7
8
9
94.9
67.82
58.49
33.02
26.99
24.7
23.95
21.84
20.44
5.10
5.26
10.14
34.63
39.76
45.46
56.44
65.3
69.56
0
26.91
31.37
32.35
33.24
29.85
19.61
12.86
10.0
1.343
1.351
1.357
1.363
1.372
1.376
1.380
1.382
1.383
Table 4.1.2 (iii)
(iii)
15% By Weight
SL. No
XA
XB
XC
Refractive
Index
1
2
3
4
5
6
7
8
9
96.7
66.04
54.2
44.0
26.16
28.91
25.03
21.76
12.39
3.3
7.75
15.27
23.0
36.86
51.0
56.41
65.15
82.92
0
26.21
30.53
33.0
36.98
20.18
18.56
13.08
4.68
1.339
1.342
1.349
1.353
1.361
1.374
1.379
1.381
1.386
Table 4.1.3 (i)
3. SALT: POTASSIUM CHLORIDE (KCl)
(i)
5% By Weight
SL. No
XA
XB
XC
Refractive
Index
1
2
3
4
5
6
7
8
9
96.3
80.14
57.48
43.42
30.35
25.35
20.54
17.75
10.33
3.7
10.95
21.75
32.07
46.82
48.89
50.71
58.20
75.69
0
8.91
20.77
24.51
22.83
25.75
28.74
24.04
13.98
1.344
1.354
1.363
1.368
1.373
1.375
1.381
1.387
1.389
45
Table 4.1.3 (ii)
(ii)
10% By Weight
SL. No
XA
XB
XC
Refractive
Index
1
2
3
4
5
6
7
8
9
96.45
71.12
56.69
44.39
28.16
26.08
24.46
20.40
10.64
3.55
8.73
16.69
24.51
41.48
48.01
57.63
63.85
74.45
0
20.15
26.62
31.1
30.36
25.91
17.91
15.75
14.9
1.344
1.352
1.359
1.365
1.374
1.378
1.380
1.381
1.384
Table 4.1.3 (iii)
(iii)
15% By Weight
SL. No
XA
XB
XC
Refractive
Index
1
96.6
67.74
55.57
45.03
26.92
29.10
25.30
13.93
12.61
3.4
7.95
15.65
23.78
37.93
51.24
57.0
73.79
84.36
0
24.31
28.78
31.19
35.15
19.66
17.7
12.28
3.03
1.338
1.343
1.350
1.356
1.364
1.371
1.378
1.382
1.388
2
3
4
5
6
7
8
9
46
TABLE – 4.2
EQUILIBRIUM DATA
(For All Systems)
System: Water + Acetone + 1-Butanol
TABLE -4.2.1
1. NO SALT
SL. No.
XAA
1
2
3
4
0.86
0.882
0.893
0.915
SL. No.
XAB
1
2
3
4
0.305
0.272
0.261
0.198
Water Layer
XBA
0.11
0.099
0.089
0.081
Butanol Layer
XBB
0.588
0.61
0.632
0.775
XCA
Refractive
Index
0.13
0.125
0.108
0.09
1.354
1.352
1.347
1.342
XCB
Refractive
Index
0.124
0.116
0.096
0.012
1.3728
1.374
1.376
1.379
TABLE -4.2.2(i)
2. SODIUM CHLORIDE (NaCl)
(i)
5% By weight
SL. No.
X AA
Water Layer
XBA
XCA
1
2
3
4
0.588
0.709
0.827
0.851
0.275
0.187
0.125
0.1083
0.13
0.09
0.055
0.051
47
%Wt. Salt Refractive
index
3.21
3.92
4.08
4.5
1.363
1.358
1.354
1.352
SL. No.
X AB
Butanol Layer
XBB
XCB
1
2
3
4
0.261
0.143
0.11
0.099
0.566
0.75
0.827
0.849
0.18
0.12
0.08
0.07
%Wt. Salt Refractive
Index
1.69
1.372
1.22
1.377
0.61
1.382
0.60
1.384
TABLE -4.2.2(ii)
(ii) 10% By weight
SL. No.
X AA
Water Layer
XBA
XCA
1
2
3
4
0.61
0.663
0.676
0.687
0.088
0.05
0.077
0.053
SL. No.
X AB
Butanol Layer
XBB
XCB
1
2
3
4
0.244
0.24
0.239
0.22
0.468
0.47
0.481
0.492
0.295
0.28
0.27
0.26
0.3
0.29
0.28
0.27
%Wt. Salt Refractive
index
5.94
6.33
7.56
8.2
1.356
1.352
1.349
1.348
%Wt. Salt Refractive
Index
4.19
3.62
2.31
1.8
1.376
1.3764
1.377
1.3774
TABLE -4.2.2(iii)
(iii) 15% By weight
SL. No.
X AA
XBA
1
2
3
4
0.525
0.533
0.599
0.6265
0.158
0.153
0.111
0.1035
Water Layer
XCA
0.335
0.314
0.29
0.27
48
%Wt. Salt Refractive
index
9.21
11.02
11.54
13.4
1.354
1.350
1.346
1.343
SL. No.
X AB
Butanol Layer
XBB
XCB
1
2
3
4
0.18
0.17
0.168
0.163
0.625
0.665
0.675
0.698
0.195
0.165
0.15
0.13
%Wt. Salt Refractive
Index
5.79
4.0
3.26
1.25
1.376
1.378
1.380
1.382
TABLE -4.2.3 (i)
3. SALT: POTASSIUM CHLORIDE (KCL)
(i)
5% By weight
SL. No.
X AA
Water Layer
XBA
XCA
1
2
3
4
0.80
0.8625
0.9125
0.915
0.09
0.0625
0.05
0.041
SL. No.
X AB
Butanol Layer
XBB
XCB
1
2
3
4
0.183
0.147
0.124
0.122
0.577
0.643
0.676
0.698
0.11
0.07
0.04
0.012
0.24
0.21
0.20
0.18
%Wt. Salt Refractive
index
3.15
3.3
3.5
4.32
1.366
1.362
1.356
1.348
%Wt. Salt Refractive
Index
1.55
1.68
1.46
0.77
1.387
1.3875
1.3876
1.388
TABLE -4.2.3 (ii)
(ii) 10% By weight
SL. No.
X AA
Water Layer
XBA
XCA
1
2
3
4
0.599
0.698
0.731
0.783
0.151
0.102
0.089
0.077
0.25
0.20
0.18
0.14
49
%Wt. Salt Refractive
index
6.13
7.3
7.37
8.34
1.359
1.352
1.349
1.346
SL. No.
X AB
Butanol Layer
XBB
XCB
1
2
3
4
0.27
0.248
0.223
0.215
0.47
0.522
0.577
0.61
0.26
0.23
0.20
0.175
%Wt. Salt Refractive
Index
3.95
2.80
2.48
1.11
1.377
1.3772
1.378
1.380
TABLE -4.2.3 (iii)
(iii) 15% By weight
SL. No.
X AA
Water Layer
XBA
XCA
1
2
3
4
0.615
0.632
0.676
0.698
0.125
0.118
0.089
0.082
SL. No.
X AB
Butanol Layer
XBB
XCB
1
2
3
4
0.175
0.167
0.162
0.158
0.625
0.643
0.654
0.676
0.26
0.25
0.235
0.22
0.20
0.19
0.175
0.16
50
%Wt. Salt Refractive
index
10.1
11.45
12.63
12.87
1.346
1.344
1.342
1.340
%Wt. Salt Refractive
Index
4.7
3.53
2.27
2.26
1.372
1.374
1.376
1.378
TABLE – 4.3
1. COSTANTS Ln A AND B IN MODIFIED CAMPBELL EQUATION
Table 4.3.1
SALT
NO SALT
NaCl
KCl
% Wt.
Ln A
B
0
5
10
15
5
10
15
0.0165
0.0021
0.0475
-0.1289
0.1733
0.0632
-0.06
3.0335
1.3544
0.8598
0.956
0.59
0.7948
1.0
2. COSTANTS Ln A AND B IN HAND’S Plot
Table 4.3.2
SALT
NO SALT
NaCl
KCl
% Wt.
0
5
10
15
5
10
15
Ln A
0.0215
-0.0064
0.2445
-0.0578
0.2324
0.0808
0.0016
51
B
4.5726
1.44
0.8365
0.557
1.2937
1.1479
0.7517
TABLE-4.4
1. CONSTANTS a, b, c, d IN MODIFIED CAMPBELL EQUATION
Table – 4.4.1
SALT
% Wt.
a
NO
SALT
0
0.0165
NaCl
5
10
15
5
10
15
0.0165
0.0165
0.0165
0.0165
0.0165
0.0165
KCl
b
c
d
3.0335
-0.0028
0.0031
-0.0096
0.0314
0.00467
-0.0051
Regration
Coefficient
0.8588
3.0335
3.0335
3.0335
3.0335
3.0335
3.0335
-0.335
-0.217
-0.1358
-0.4887
-0.2238
-0.1355
0.9957
0.9888
0.9751
0.9818
0.9743
1
2. CONSTANTS a, b, c, d IN EISEN-JOFFE EQUATION
SALT
% Wt.
a
NO
SALT
NaCl
0
0.0215
5
10
15
5
10
15
0.0215
0.0215
0.0215
0.0215
0.0215
0.0215
KCl
b
c
d
4.5726
-0.0055
0.0223
-0.0053
0.0422
0.0059
-0.0013
52
4.5726
4.5726
4.5726
4.5726
4.5726
4.5726
Regration
Coefficient
0.8824
-0.6265
-0.3736
-0.2677
-0.6557
-0.3425
-0.255
0.9901
0.8777
0.9113
0.9874
0.9655
0.9897
TABLE – 4.5
COMPARISION BETWEEN XCB – OBSERVED AND XCB CALCULATED
Table 4.5.1
1. SALT : SODIUM CHLORIDE (NaCl)
% Wt. Salt
XCB
observed
Campbell Equation
XCB
% Error
Calculated
0.18
0.063
0.12
0.0385
0.08
0.0197
0.07
0.0178
0.3
0.391
10
0.29
0.373
0.28
0.362
0.27
0.350
0.195
0.261
15
0.165
0.245
0.15
0.227
0.13
0.212
Standard Deviation-0.1385
Root Mean Square Deviation-0.0808
65
67.9
75.4
74.5
30.3
28.62
29.3
29.63
33.85
48.48
51.33
63.07
5
53
Eisen-Joffe Equation
% Error
XCB
Calculated
0.0634
64.77
0.0374
68.83
0.0162
79.75
0.0142
79.71
0.447
49.0
0.401
38.27
0.391
39.64
0.383
41.85
0.0426
78.15
0.0433
73.75
0.0394
73.73
0.382
70.61
Standard Deviation0.1806
Root
Mean
Square
Deviation-0.1292
Table 4.5.2
2. POTASSIUM CHLORIDE (KCl)
% Wt. Salt
XCB
observed
Campbell Equation
XCB
% Error
Calculated
0.24
0.405
0.21
0.310
0.20
0.223
0.18
0.109
0.26
0.384
10
0.23
0.322
0.20
0.295
0.175
0.242
0.20
0.226
15
0.19
0.217
0.175
0.204
0.16
0.192
Standard Deviation-0.0813
Root Mean Square Deviation-0.0834
68.75
47.61
11.5
39.44
47.69
40.0
47.5
38.28
13.0
14.21
16.57
20.0
5
54
Eisen-Joffe Equation
XCB
% Error
Calculated
0.0756
68.5
0.049
76.66
0.0203
89.85
0.0433
75.94
0.207
20.38
0.149
35.21
0.138
31.0
0.101
42.28
0.327
63.5
0.321
68.94
0.296
69.14
0.285
78.13
Standard Deviation-0.1103
Root
Mean
Square
Deviation-0.1245
RESULT AND DISCUSSION
The liquid-liquid equilibrium for the given ternary system was observed at atmospheric
pressure and a temperature of 25 0C. The ternary solubility data and the tie line data are
determined in the presence of NaCl, KCl at 5%, 10% and 15% concentration for the system
water + acetone + 1-butanol at same temperature. It had seen from the diagram that the
addition of salts accelerate the distribution in favour of 1-butanol layer especially at higher
salt concentration. The solubility decreases in presence of the salt and increases the
heterogeneous zone of the system. Heterogeneous area plays an important role in liquidliquid equilibrium. In the supplied system, it was seen that the areas of the solubility curve
are more in case of salt addition than that of without salt. More acetone is shifted towards the
butanol phase with increasing salt concentrations. This process is generally known as “salting
out effect” and is caused by the fact that the presence of high amount of hydrated ions
decreases the availability of the water molecules in the aqueous phase to the salvation of
other solvents. The concentration of acetone in organic phase increases by presence of salts
and hence enlargement of the two phase region occurred. These process increase with salt
concentration and are maximum at salt saturation. From the binodial curve it is seen that the
salting out effect is more in NaCl. Hence the order of effectiveness of salt was as follows.
NaCl > KCl. The orders of effectiveness of the salts based on the salt effect parameter were
derived from Eisen – Joffee Equation and modified Campbell equation.
55
CHAPTER – 5
CONCLUSION
The liquid-liquid equilibrium diagram for ternary system water + 1-butanol + acetone was
determined at 250C. The effects of salt like NaCl and KCl on the ternary system at different
concentrations were observed at the same temperature. Eisen – Joffe and Campbell
correlations are used for the determination of the corresponding parameters for the given
system with and without salt, which are appropriate for interpolation of the equilibrium data.
In case of all the systems containing dissolved salt, under study it is observed that at lower
concentration modified Campbell equation gives more error. From the present experiment it
was seen that modified Campbell equation correlate better in presence of NaCl compared to
KCl. The experimental results lead to the conclusion that a salting out effect exists for all the
salts under study, increasing for higher salt concentrations. In conclusion it may be indicated
that concerted efforts on the observations of the salt effect on the distribution of a solute
between two partially miscible liquids have a potential scope for engineering applications.
The use of solid inorganic salt in place of liquid separating agent in extraction process has
great advantages. It is because by use of small amount of solid salt bring about a substantial
change in phase equilibrium in ternary liquid system. This fact is observed and conformed in
case of ternary system under investigation. Thus it is concluded that this technique can be
used effectively for extraction of liquid (solute) using solid salt.
56
REFERENCES
[1] Gomis Vicente, Prats Daniel, Ruiz Francisco, Asensi Juan Carlos, Reus Francisco,
quaternary liquid-liquid equilibrium: water-acetic acid-2-butanone-cyclohexane at 25°C,
Elsevier, Fluid Phase Equilibria 106 (1995), 203 -211.
[2] Hasseine A., Meniai A H, Korichi M, salting out effect of single salt NaCl and KCl on the
LLE of the system(Water + acetone + toluene), (Water + cyclohexane + 2-propanol) and
(Water + xylene + methanol), science direct, Desalination 242 (2009), 264-276.
[3] Chen Jui Tang, Chen Ming-Chung, salt effect on LLE for the ternary system (water + Nmethyl-2-pyrrolidone + 1-pentanol), science direct, Fluid Phase Equilibria 266(2008), 1-7.
[4] Bourayou N., Meniai A H, Experimental and theoretical study of the influence of salt on
liquid phase equilibrium for totally miscible organic compound with water, science direct,
Desalination 185 (2005), 473-481.
[5] Pai M. U., Rao K. M., salt effect on liquid-liquid equilibria in the ethyl Acetate-ethyl
alcohol-water system J. Chem. Engg. Data 11 (1966), 353-356.
[6] Santos Fania S., d’Avila Saul G., Aznar Martin, salt effect on liquid-liquid equilibrium of
water + 1-butanol + acetone: experimental determination and thermodynamic modeling,
science direct, fluid phase equilibria 187-188 (2001), 265-274.
[7] Vakili-Nezhaad G.R., Mohsen-Nia M., Taghikhani V., salting out effect of NaCl and KCl
on the ternary LLE data for the systems of (water + propionoic acid + isopropyl methyl
ketone) and of (water + propionoic acid + isobutyl methyl ketone), science direct, J. Chem.
Thermodynamics 36 (2004), 341 – 348.
[8] Erol Ince, (Liquid + liquid) equilibria of the (water + acetic acid + dibasic esters mixture)
system, science direct, J. Chem. Thermodynamics 38(2006), 1669-1674.
[9] Hung Shih-Bo, Lin Ho-Mu, Yu Cheng-Ching, Huang Hsiao-Ping, Lee Ming-Jer,
Liquid–liquid equilibria of aqueous mixtures containing selected dibasic esters and/or
methanol, science direct, Fluid Phase Equilibria 248 (2006), 174–180.
[10] Hu Mancheng, Wang Meixia, Li Shu ni, Jiang Yucheng, Guo Haiyan, Liquid-liquid
equilibrium for water + 1-propanol/2-propanol + potassium chloride + cesium chloride
quaternary systems at 298.1K, science direct,fluid phase Equilibria 263 (2008), 109-114.
[11] Santos G. R, d’Avila S.G, Aznar M., salt effect of KBr on liquid-liquid equilibrium of
water/ethanol/1-pentanol system, Brazilian journal of chemical engineering, 17(2000), 721734.
57
[12] Tan T.C., Kannangare k.K.D.D.S., Liquid-liquid equilibria of water/1-propanol/methyl
ethyl ketone/potassium chloride, science direct, fluid phase Equilibrium 190 (2001), 179-189.
[13] Solimo Horacio N., Bonatti Carlos M., Zurita Jose L., de Doz Monica B. Gramajo ,
Liquid-liquid equilibria for the system water + propionoic acid + 1- butanol at 303.2K, Effect
of addition of sodium chloride, Elsevier, Fluid-Phase Equilibria137 (1997), 163-172.
[14] R. Pedraza, F. Ruiz, M.D. Saquete, V. Gomis,Liquid-liquid-solid equilibrium for the
water + sodium chloride + potassium chloride + 1- butanol quaternary system at 250C,
Science direct, Fluid Phase Equilibria 216 (2004), 27–31.
[15] Tan T.C., Aravinth S., Liquid-liquid equilibria of water/acetic acid/1- butanol systemeffects
of
sodium(potassium)
chloride
and
correlation,
Elsevier,
Fluid
Phase
Equilibria163(1999),243–257.
[16] Othmer Donald f., Tobias Philip E., Liquid-liquid extraction data – tie line correlation,
Industrial & Engineering Chemistry, 34 (6) (1942), 693-696.
[17] Eisen E.O., Joffe J., Salt effect in liquid-liquid equilibrium, Journal of Chemical &
Engineering Data, 11 (4) (1966), 480-484.
[18] Govindarajan M., Sabarthinam PL., Salt effect on liquid-liquid equilibrium of the methyl
isobutyl ketone – acetic acid – water system at 35 0C, Elsevier, fluid phase equilibria, 108
(1995), 269- 292.
[19] Campbell H. R., Shallal A.K., Bauer H.H., Salting effects in several alcohol- electrolytewater systems, Journal of Chemical & Engineering Data, 15 (1970), 311-312.
[20] Desai M.L., Eisen E. O., Salt effects in liquid-liquid equilibriums, Journal of Chemical
& Engineering Data, 16(2) (1971), 200-202.
[21] Acharya Arun, Salt effect on loquid-liquid equilibrium for ternary system n- butanol + n
– propanol + water, M. Tech. Thesis, Submitted to department of chemical Engg. Rourkela,
June 2004.
[22] Swabb, L.E., Mongan, E.L., Solvent extraction from aqueous solution, Effect of addition
of inorganic salts, Chem. Eng. Prog. Sym. Ser. 48 (1952), 40-45.
[23] Campbell J.A., Distribution equation, Industrial & Engineering Chemistry, 36 (1944),
1158-1161.
58
[24] Hand D.B., The distribution of consolute liquid between two immiscible liquids, J. Phys.
Chem., 34 (1930), 1961-2000.
[25] Setschenow J., Z. Phys. Chem., 4 (1889), 117.
59
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement