ABSTRACT
Immiscib Immiscible le substance substances s are caused by the solubility solubility properti properties es of liquid. liquid. In most cases for liquids, two immiscible liquids cannot mix even with the addition of a tertiary component. But the addition of a highly polar substance demonstrates a change in its solubility. In this experiment, we used butanol, acetic acid and water as tertiary components. We crea create ted d four fourte teen en (1! (1! mixt mixtur ures es of buta butano noll and and acet acetic ic acid acid with with di"e di"errent ent compositions and then they were allowed to achieve thermal equilibrium. #ach of them was then titrated with water (at $%&'! until permanent turbidity appeared. efractive indexes were then measured by a refractor and then recorded. Water was then added to the mixture and the mixture was allowed to form separate layers. efractive indexes were then recorded again for each layer. )sing a ternary plot and the gathered data from the earlier parts, we draw the boundary between two*phase and one*phase systems and the corresponding tie lines. INTRODUCTION
#xtrac #xtractio tion n of consti constitu tuent ents s by solve solvent nt is a very very common common practi practice ce in chemi chemical cal process processing ing where where a mixture mixture containing containing separabl separable e componen components ts is treated treated with a solvent in which one or more of the desired components are preferentially soluble. +his type of extraction extraction is called liquid*liquid liquid*liquid extraction in which which a solution is brought brought into contact with a second liquid (solvent! essentially immiscible with the rst one in order to bring about transfer of one or more components from the solution into the second solvent. It is an e"ective alternative process to distillation process. -iquid* liquid extraction process is the most useful method for purication, enriching and separation of components of very close volatility and of heat sensitive. In many many cases, cases, butan butanol ol is found found in its aqueou aqueous s form. form. Butan Butanol ol is an impor importan tantt laboratory reagent, thus, the study of butanol extraction from its aqueous solution is fascinating all the time. In this study, in order to nd out the proper solvent for the separation of butanol from aqueous solution, phase equilibrium data and mutual solubility data were therefore obtained experimentally by using solvents. eparation fact factor or whic which h is a quan quanti tita tati tive ve inde index x of e"ec e"ecti tive vene ness ss of sepa separa rati tion on has has been been computed from these data. eparation process process in which a solute in a feed stream is extracted by contacting the feed with a solvent is called solvent extraction. +he solute has to be soluble in both the feed and solvent in order for the extraction to ta/e place. +he solvent and the feed feed for indust industria riall extra extracti ction on opera operatio tions ns are are normal normally ly parti partial ally ly solubl soluble e in one another. 0 ternary system will be formed consists of the feed, solvent and solute. +he composition of such a system can be conveniently represented represented on an equilateral triangle plot with each corner of the triangle presenting one of the three components. +he purpose this experiment was carried out was to determine the bimodal curve and the typical tie lines of the water*water*butanol acid system. +he points on the bimodal curve was determined using the mass fractions of water, butanol and the other solvent of mixtures after the it was slowly added until a single phase clear solution is obtained. +he tie line is drawn using the mass fractions of butanol, water and the other component of mixtures , with also their mass ratios using trial and error method. +hree phase diagram will be drawn in this experiment. age 1 of 11
METHODOLOGY
0. '8#5I'0- ; 000+)
urve, the chemicals involve were distilled water, butanol and acetic acid. tandard glass wares were used (bea
ater and 1.45 6a78. ame apparatus were used as in rst part. eparation of phases had been done by mea
:
f the waste of chemicals had to be followed in the end of the experiment. When doing the titration, it had to b
B. #<#I5#6+0- 7'#=)# art 1. =etermined solubility curve had been done by starting with determining the rst two points in the curve which lies on the hori>ontal axis of the curve. +hese two points were the solubility of butanol in water and the solubility of water in butanol. +he cloudy appearance had been the evidence for both solubility. +he other points on the curve were then determined by adding acetic acid in the two* phase mixture until it turns bac/ into one phase. +he transition could be observed by the disappearance of turbidity in the stirred solution. •
•
$4ml of butanol was placed in an empty #rlenmeyer 3as/ which was weighed before using. It was weighed again once the butanol was poured into it. +his had been titrated with distilled water giving a cloudy appearance. ?nowing the density of the butanol and water, the mass of butanol and water could be identied. +he mass percentages had been used to determine the rst point in the curve. +his process had been repeated but this time $4ml of water was used. +he second point on the curve could now been determined.
age 2 of 11
•
•
•
• •
• •
tarting from $4ml of butanol and %ml of water placed in a $44ml paralm*covered #rlenmeyer 3as/. 0cetic acid had been added until turbidity disappears. +he volume of acetic acid added was then recorded. 0ddition of %ml aliquot of water had been done to the mixture from the previous step and it had been titrated again with acetic acid. It had been continued until @4 ml water had been added. 0ddition of 14ml of aliquot of water was now used and it had been /ept titrated until a total of 114 ml of water had been added. Aolume of acetic acid used in every stage had been recorded. ?nowing the volume and density of the three liquids, their masses could be computed. 8ence, their mass percentages in each stages could be determined. +rial $ had been done to get the average composition of ternary mixtures. +he average composition was then used to plot the points in the curve.
art$.
•
•
•
•
•
•
In order for the diagram to be completed, a tie lines had been obtained. 2or this, preparation of two*phase mixtures was needed. +hese phases had to be separated using separatory funnel. +hese separated mixtures had to be titrated in order to determine the amount of acid the solutions contained. +he prepared 1.45 6a78 was the base used to titrate the aqueous acid containing solutions. +he two*phase mixture which had been assigned to our group was prepared by mixing @4ml distilled water, 1%ml butanol and $ml acetic acid. +his mixture had been placed in the separatory funnel and it had been allowed to settle for a while. +he two separated mixture had been labeled +$(+op hase! and -$(Bottom hase! respectively. 0fter obtaining two separate mixtures, both had been titrated with 1.45 6a78. 0n indicator had been used henolphthalein to see the color change right when the mixtures had been titrated. 0 pale pin/ color solution was expected. +he volume of the base which had been used to titrate the mixtures were the volume of the acid the mixtures contained. +hus, /nowing the volumes and densities of the three liquids involve, the masses of each could now be determined. +he mass of the two phases could also be computed which was then used to determine the points for the tie lines. +rial $ had also been done.
age 3 of 11
RESULTS AND DISCUSSIONS
+ernary phase diagrams are @ component systems. +o construct a ternary diagram it is necessary to /now the three binary systems for the three components. In this experiment the three components are butanol, water, and acetic acid. +he sides of the triangle corresponds to the mole percent of each of the components with respect to the other two . +he obCective of this activity is to be able to come up with a curve which will show the concentration of each components at equilibrium provided that the amount of butanol remains constant. +o obtain this, the activity was divided into two parts, the rst one was to determine the two ends of the the curve on the side of the butanol and that of water. 6o acetic acid was present during this time. +he points on the curve was determined by titrating the butanol*water system with acetic acid. 0. olubility of Immiscible -iquids +able $*1a olubility of Butanol in Water Aolume of Aolume of 5ass of Butanol 0dded Butanol Water $4 ml @.$ m1E.$ g +able $*1b olubility of Water in Butanol Aolume of Aolume of 5ass of Water 0dded Water Butanol $4 ml @.H m$4 g
5ass 0dded Water @.$ g
of D 5ass Butanol
5ass 0dded Butanol @.4 g
of D 5ass Water
F@.%1
FE.GE
D 5ass Water 1E.G D 5ass Butanol
[email protected]
B. =etermination of 'loud oint +able $*$a9 +rial 1 5ixtur Aolume =ata (m-! Butan Water 0cetic e ol 0cid 1 $4 % 1. m$ $4 14 .4 m@ $4 1% %. m $4 $4 E.$ m% $4 $% H.1 mE $4 @4 H.G mH $4 4 G. mF $4 %4 14.% m-
5ass (g! Butan Water ol 1E.$ @.4 1E.$ 14.4 1E.$ 1%.4 1E.$ $4.4 1E.$ $%.4 1E.$ @4.4 1E.$ 4.4 1E.$ %4.4
0cetic 0cid 1.H .$4 %.EH E.%1 H.E F.@4 G.FH 11.4@
5ass ercent (D! Butan Water 0cetic ol 0cid H1.E $$.4E E.F %@.$G @$.FG
[email protected]$ @.G 4.EF 1%.@F @H.G@ E.F@ 1%.$ @@.$G %1.@F 1%.@@ $G.H$ %%.4% 1%.$@ $.%$ E4.% 1.G $4.GF E.H 1.$F
age 4 of 11
G
$4
E4
14
$4
H4
11
$4
F4
1$
$4
G4
1@
$4
144
1
$4
114
11.% m1$.E
[email protected] m1. m1%.$ m-
+able $*$b9 +rial $ 5ixture Aolume =ata (m-! Butan Water 0cetic ol 0cid 1 $4 % 1.1 m$ $4 14 @.G m@ $4 1% %.@ m $4 $4 E.@ m% $4 $% H.1 mE $4 @4 H.F mH $4 4 G.@ mF $4 %4 14.@ mG $4 E4 11.% m14 $4 H4 1$.E m11 $4 F4 1@. m1$ $4 G4 1.1 m1@ $4 144 1.F m1 $4 114 1%.$ m-
1E.$
E4.4
1$.4F
1F.@%
EH.GH
[email protected]
1E.$
H4.4
1@.$@
1E.$G
H4.4
1@.@1
1E.$
F4.4
1.$F
1.EE
H$.1
1$.G@
1E.$
G4.4
1%.1$
1@.@%
H.1F
1$.E
1E.$
144.4
1%.GE
1$.$E
H%.EH
1$.4F
5ass (g! Butan Water ol 1E.$ %.44
0cetic 0cid 1.1%%
5ass ercent (D! Butan Water 0cetic ol 0cid H$.H $$.@H %.1H
1E.$
14.44
.4G%
%@.H
@@.41
1@.%$
1E.$
1%.44
%.%E%
.FE
4.F4
1%.1
1E.$
$4.44
E.E1%
@H.F
E.H1
1%.%
1E.$
$%.44
H.%%
@@.@4
%1.@F
1%.@$
1E.$
@4.44
F.1G
$G.HF
%%.1E
1%.4E
1E.$
4.44
G.HE%
$.FE
E4.E
1.F4
1E.$
%4.44
$1.4@
E.G$
1.4
1E.$
E4.44
1F.@%
EH.FH
[email protected]
1E.$
H4.44
14.F1 % 1$.4H % 1@.$@
1E.$G
H4.4
1@.@1
1E.$
F4.44
1.4H
1.EG
H$.%%
1$.HE
1E.$
G4.44
1@.@G
H.@F
1$.$
1E.$
144
1.F4 % 1%.%
1$.@4
H%.G1
11.F4
1E.$
114
1%.GE
11.4
HH.@F
11.$@
+able $*@9 0verage 'omposition of +ernary 5ixtures age 5 of 11
1 $ @ % E H F G 14 11 1$ 1@ 1
5ass ercent (0verage of +wo +rials! Butanol Water H1.GE% $$.$1% %@.@F4 @$.G% .4 4.HH @H.FF% E.HH @@.$G@ %1.@F $G.H% %%.14% $.% E4.%G $1.44% E.F@ 1F.@% EH.GH 1E.$G H4.4 1.EH% H$.F 1@.@H H.$F 1$.$F H%.HG
acetic %.F$%
[email protected] 1%.$E 1%.@% 1%.@$% 1%.1% 1.FH 1.1E
[email protected] 1@.@1 1$.F% 1$.@% 11.G
age 6 of 11
It is a common /nowledge that alcohols such as butanol are miscible in water. +ruth is, It does at certain concentrations and this was proven by the addition of acetic acid. )pon addition andwhen the solution was stirred, it came to a point that a cloudyJturbid phase appears , this is the transition from one region to another can be observed by appearance (or disappearance! of cloudiness or turbidity in the solution. +he turbidity results from scattering of light by the large number of very small KoilyL droplets of the second phase that are produced when the system is stirred. ometimes it is easier to see this when stopping the stirring brie3y.If the three components are mixed to give an overall system composition that falls in the $* phase region, the system will separate into two phases9 a phase rich in water and 2ig. $*1. 5ixture $ composed of @4 m- water, $ m- 0cetic 0cid, 1% m-Butanol. another rich in 1*butanol. +o determine the other points, water was added in % ml increment each time turbidity appears. When water is added, the mixture goes bac/ to the one phase region, and each time the cloudiness appears, the point falls in the two*phase region which is below the curve. 1 points was plotted, the end point of the last one became to diMcult to recogni>e, anyhow, those were enought to complete the curve. 7n the second part of the experiment, tie lines were constructed to validate the precision and accuracy of the curve. 0 mixture of water, acetic acid, and butanol in di"erent concentrations were prepared. +his concentrations all resulted to two* phase after a while. #ach phase was then recovered, the lower phase being the water*rich mixture, and the upper phase being the butanol rich mixture. +he plot of their *mole fractions fell on each side of the curve, the end point of the tie*line. +he mole fractions of each component prior to separating the two phases were also plotted and as expected, it fell below the curve and passes along the tie*line.
age 7 of 11
2igure $*$9 +ernary phase diagram of wateNacetic acid*butanol and tie line constructed from @4 m- water, $
0s mentioned earlier, the points along the curve shows the mass percentage of the three components at equilibrium, information regarding phase equilibria can be predicted by a simple rule (KOibbs phase ruleL!9 fPcQpR$
age 8 of 11
where c is the number of components and p is the number of phases present in the system. +he degrees of freedom f, or variance, gives the number of variables (e.g., pressure, temperature, composition, etc.! that must be given to completely describe the system, or to locate the state of the system on the phase diagram. In this experiment there were @ components, and creates a two*phase system which gives the value fP@, however theR $ in the equation already corresponds to pressure and temperature, so aside from those $, the other variable that helped in locating the mixture in the diagram is the concentration. SAMPLE CALCULATIONS
olubility of Immiscible -iquids Solubility of Butanol in water 5butanol P (4.F1 gJm-!($4m-! P 1E.$4 gbutanol 58$4 P (1.4 gJm-!(@.$m-! P @.$4 g 8$7 16.2
DButanol massP
16.2 + 3.2
100
x
P
F@.%1D D8$7mass P 144D * F@.%1D P 1E.GD =etermination of 'loud point Trial 1, Mixture #1 5butanol P (4.F1 gJm-!($4.4m-! P 1E.$4 gbutanol 58$7 P (1.4 gJm-!(%.4m-! P %.4 g 8$7 5acetic P (1.4% gJm-!(1.m-! P 1.H gacetic -Mass Percent 16.2
Dbutanol P
16.2 + 5.0 + 1.47
x 100
5.0
P
16.2 + 5.0 + 1.47
x 100
P
Dacetic P
16.2 + 5.0 + 1.47
x 100
'omposition
Solubility of Water in Butanol 5bu tan ol P (4.F1 gJm-!(@.Hm-! P @.4 gbutanol 58$4 P (1.4 gJm-!($4m-! P $4.4 g 8$7 DButanol massP
2
3.0 + 20
x 100
P
P
Trial 2, Mixture #1 5butanol P (4.F1 gJm-!($4.4m-! P 1E.$4 gbutanol 58$7 P (1.4 gJm-!(%.4m-! P %.4 g 8$7 5aa P (1.4% gJm-!(1.1m-! P 1.1%% gaa -Mass Percent
+ernary
=71.965
= 5.825
=etermination of +ie*-ines (elative 5asses of +wo*phase systems! Trial 1, Mixture #2 5butanol P (4.F1 gJm-!(1%m-! P 1$.1% gbutanol 58$7 P (1.4 gJm-!(@4.4m-! P @4.4 g 8$7 5acetic P (1.4% gJm-!($.4m-! P $.14 gacetic
16.2
Dbutanol P 71.46 + 72.47
Dbutanol P
of
2
P
E.FD 0verage 5ixtures Butanol9
Dacetic P
+ 5.17
[email protected]D D8$7mass P 144D *
[email protected]D P FE.GED
$$.4ED 1.47
6.48
3.0
H1.ED D8$7
0cetic 0cid9
16.2 + 5.0 + 1.155
x 100
P
H$.HD
age 9 of 11
5.0
D8$7
P
16.2 + 5.0 + 1.155
x 100
P
$$.@HD 1.155
Dacetic P
16.2 + 5.0 + 1.155
x 100
P
(+itration =ata9 'omposition of +wo hases! Trial 1, Mixture #2 m ol 1 nacetic P n6a78 P ( L !(4.41%F -! P 4.41%F mol
%.1HD
mol
nacetic P n6a78 P (1
L
¿
(4.4$%-! P
Water9 22.06 +22.37
D8$7 P
2
=22.215
4.4$% mol Dwtacetic,+$P
(
0.0158 mol 60
=etermination of +ie*-ines
13.925 g
g ) mol
x 100 =6.79
age 10 of 11
CONCLUSION
+hrough the experiment, the students were able to learn how to determine the bimodal curve and tie lines in chec/ing the composition of the water*butanol* acetic acid system. Based on the results of the experiment, the percentages obtained can be considered accurate and precise due to the closeness of the values. 8owever, certain errors were also present, such as the not so perpendicular eye level on measuring the volumes of liquids, overruns during titration, and di"ering temperature of the room. It is a wondrous experience to actually prove what is only learned theoretically. REFERENCES
(Gth #dition!. hysical 'hemistry. a . 0/ins, ; S. de aula, Physical Chemistry 6ew Tor/9 W8 2reeman and 'ompany. 2eigenson, O. W., ; Bubolt>, S. +. (Sune E, $441!. +ernary hase =iagram of =ipalmitoyl*'J=ilauroyl*'J'holesterol9 6anoscopic =omain 2ormation =riven by 'holesterol. Bio!hysical "ournal, $HH%N$HFF. (Hth #dition!. a S. 5. mith, 8. '. Aan 6ess, ; 5. 5. 0bbott, ntro$uction to Chemical %n&ineerin& T'ermo$ynamics 5cOraw 8ill.
