Distillation of Binary Liquids

ADAMSON UNIVERSITY College of Engineering Chemical Engineering Department  M a n i l a

Experiment no. 1

DISTILLATION O !INARY LI"UIDS

S#$mitte% $&'

Lavilles, Francis Dominic Lee Gee Hyun Lojica, Kathlyn Joyce M.

Date performe%'  July 18, 201 Date (#$mitte%'  July 2!, 201

A!STRACT' The main objective of the experiment is to construct a boiling point composition diagram for a binary liquid   system. Distillation is a process in which two components a re separated by boiling the component that has a lower  boiling point compared to the other. The researchers prepared a simple distillation set-up. 50-m of glacial acetic acid  and !-m of distilled water were mixed and were used in the distillation of the binary liquids. "fter the distillates have been collected# they were titrated with !$ %a&' and the mole percentages of acetic acid were computed. The results  showed that as the amou nt of water in the mixture increases# the boiling point an d the concentration of acetic acid  decreases. The results were graphed in a temperature vs (mole acetic acid of the liquid and vapor mixture. The graph  showed that as the temperature increases# the (acetic acid also increases. The mixture is an example of an a)eotropic mixture since it cannot be separated using a simple distillation process.

INTRODUCTION'

"he #oilin$ %oint o& a mi'ture is the tem%erature at (hich the va%or %ressure o&  the li)ui* mi'ture e)uals the %ressure surroun*in$ the li)ui* an* the li)ui* chan$es into a va%or. "he va%or %ressure o& a #inary li)ui* mi'ture is a sum o& the %artial va%or   %ressures o& the t(o li)ui*s com%osin$ the mi'ture. Durin$ *istillation, the #oilin$ %oint o& the #inary li)ui* mi'ture is e)ual to the va%or %ressure. "he total %ressure can #e com%ute* usin$ +aoults La( i& the mi'ture &orms an i*eal solution. -"  -01/1 -02/2   n *istillin$ #inary mi'ture, li)ui*s #oil (hen their va%or %ressure an* e'ternal  %ressure #ecomes e)ual. & a li)ui* has a hi$h va%or %ressure at some tem%erature, the tem%erature *oes not nee* to #e increase* very much until va%or %ressure reaches the e'ternal %ressure. & he va%or %ressure is lo(, the mi'ture has to #e heate* u% a lot more to reach the e'ternal %ressure. "he li)ui* (ith hi$her va%or %ressure a t a %articular  tem%erature has the lo(er #oilin$ %oint. "he #oilin$ %oint com%osition *ia$ram can #e constructe* &or #inary li)ui*s. t (ill sho( the mole &raction (ith the corres%on*in$ #oilin$ %oints o& the li)ui*s com%osin$ the mi'ture. "his e'%eriment aims to construct a #oilin$ %oint com%osition *ia$ram &or #inary li)ui* system.

REVIE) O RELATED LITERATURE'

n 1882, "he French %hysicist Francois3Marie +aoult esta#lishe* +aoults La( (hich states that the %artial va%or %ressure o& each com%onent o& an i*eal mi'ture o&  li)ui*s is e)ual to the va%or %ressure o& the %ure com%onent multi%lie* #y its mole &raction in the mi'ture. 4on3i*eal mi'ture *eviates &rom the +aoults La(."here are many mi'tures that *eviates &rom +aoults La( 5-reo#ra6hens7iin, +u*a7ov , 201 "his e'%eriment (ill e'amine the #oilin$ com%osition *ia$ram o& a #inary system. -hase e)uili#rium in #inary system are also #ein$ thorou$hly e'amine 59lets7an, 200 in many researches. "he *ia$ram is com%ose* o& concentrations an* #oilin$ %oints. :ome su#stances have 7no(n #oilin$ %oints. "here are also ne( metho*s o& *eterminin$ the #oilin$ %oint. ;ne metho* is usin$ ultrasonic investi$ation 5+ama*oss an*  ?cetic aci* an* (ater also &orms ternary mi'ture (ith other com%oun*s li7e methyl %ro%yl 7etone #ut the system is more com%licate* than the  #inary system 59ianco, @orrea , ?rce, @orrea, 200A. ?cetic aci* an* (ater can also #e se%arate* #y other means accor*in$ to recent researches. 5@hoi, Kim, 2012 "his e'%eriment use* the #asic titration techni)ue #ut there are also various recent stu*ies a#out titration 59aranaus7ienB, -etri7aitB, MatulienB, Matulis, 200A "he e'%eriment use* the ty%ical %henol%htalein in*icator #ut there are recent stu*ies investi$atin$ other source o& in*icator &or aci* #ase titration. 5?#u$ri, ?%ea, -ritchett, 2012

MET*ODOLO+Y'

Firstly, a sim%le *istillation set3u% (as %re%are*. "hen, 03mL o& $lacial acetic aci* an* 13mL o& *istille* (ater (ere mi'e* in a 1003mL #ea7er. 4e't, 13mL o& the mi'ture (as %i%ette* into each o& the t(o 123mL Crlenmeyer &las7s an* #oth &las7s (ere la#ele* L31 to ma7e t(o trials. ?&ter(ar*s, the rest o& the solution o& the *istille* (ater an* $lacial acetic aci* (ere trans&erre* into the *istillin$ &las7 in the set u% an* the  #oilin$ chi%s (ere a**e*. :econ*ly, the mi'ture (as slo(ly *istille* an* the *istillate (as collecte* in a clean, *ry 103mL $ra*uate* cylin*er. "he tem%erature (as rea* an* (as recor*e* (hen >3mL o& the *istillate has #een collecte*. "he *istillation (as sto%%e* (hen =3mL o& the *istillate has #een collecte*. "hir*ly, 13mL o& the remainin$ solution (as %i%%ete* in the *istillin$ &las7 into each o& the Crlenmeyer &las7s that (ere %reviously la#ele* L31. "hen 23mL o& the *istillate (as %i%ette* into each o& the t(o Crlenmeyer &las7s an* #oth &las7s (ere la#ele* ;2 o& Li)ui* an* E, =.!E, an* .=E consecutively &rom run 1 to . For the va%or %hase, the avera$e mole %ercenta$es o& acetic aci* are 80.0=E, .8AE, >0.>E, 1.82E an* =.!E res%ectively. "he Emole com%osition o& the acetic aci* in #oth the li)ui* an* va%or %hase sho(e* a *ecreasin$ tren*. ?s the amount o& (ater  increases, the concentration o& the acetic aci* *ecreases. Fi$ure 1 sho(s the tem%erature 50@ vs. E mole o& acetic aci* o& li)ui* an* va%or o& the mi'ture.

n the aci*3(ater system, the attractive &orces #et(een similar molecules are $reater in com%arison to unli7e molecules. :ince there is a $reater attraction #et(een similar molecules, they ten* to have a hi$her #oilin$ %oint since it is har*er t(o se%arate the t(o. ;n the contrary, unli7e molecules have (ea7er attraction an* there&ore ten* to have a lo(er #oilin$ %oint. hen the cohesive &orces #et(een li7e molecules are $reater  than the a*hesive &orces #et(een *issimilar molecules, the *issimilarities o& %olarity lea*s #oth com%onents to esca%e solution more easily. ?t e)uili#rium, the com%osition o& the va%our a#ove the solution o& a mi'ture o&  acetic aci* an* (ater (oul* #e closer to the a6eotro%ic mi'ture than that o& the ori$inal.  4o num#er o& *istillations (ill ever result in a *istillate that e'cee*s the a6eotro%ic ratio. ?6eotro%es are a mi'ture o& at least t(o *i&&erent li)ui*s. "heir mi'ture can either have a hi$her #oilin$ %oint than either o& the com%onents or they can have a lo(er #oilin$ %oint. ?6eotro%es occur (hen &raction o& the li)ui*s cannot #e altere* #y *istillation 5-etrucci, 200!. "hus, the $lacial acetic aci* an* (ater mi'ture is an a6eotro%ic mi'ture.

"he %ossi#le sources o& error are instrumental errors an* %ersonal errors. "he  #urette %i%e that (as use* resulte* into the over titration o& the solutions. "he researchers (ere una#le to use a hal&3*ro% metho* *urin$ the titration %rocess thus resultin$ to a *ar7  color o& the solution.

CONCLUSION AND RECOMMENDATION'

?s the amount o& (ater in the mi'ture increases, the #oilin$ %oints o& the mi'ture an* the concentration o& the acetic aci* #oth *ecreases. "he $lacial acetic aci* an* (ater  mi'ture is an a6eotro%ic mi'ture since it cannot #e se%arate* usin$ a sim%le *istillation. "he com%osition o& the li)ui* %hase an* the va%or %hase are almost similar an* sho(s a same tren* in the *ecrease o& the %ercent com%osition o& acetic aci*.

"he researchers recommen*e* the use o& a #urette %i%e that has a smaller o%enin$ to %revent the solutions &rom over titratin$ an* &or the researchers to %er&orm a hal&3*ro% metho* *urin$ the titration %roce*ure.

A,,ENDI-'

:?M-LC @?L@IL?";4:

−¿

C 2 H 3 O 2(aq )+ H 2 O( L ) +¿

 Na( aq)+¿  NaOH (aq )+ H C 2 H 3 O2( aq) ≫ ¿ moles NaOH =moles acetic acid

[ MV ] NaOH 

=

mass acetic acid  MW acetic acid

33.4 mL

(

1 mmol 1 ml

masssolution=

(

)

= 33.4

1.05

33.4 mmol acetic acid

g ml

(

mmol aceticacid

)(

2 ml

60 mg

mmol

)=21 g∨ 2100 mg

)=

2004 mgof

acetic acid

masssolution− massof aceticacid =mass of water

2100 mg

−2004 mg =96 mg of water

mole of aceticacid =

mole of aceticacid =

moles of aceticacid  x 100 total moles of solution

33.4 33.4 +

ave. mole of acetic acid =

96

 x 100 = 86.23

18

mole aceticacid ∈ L 1 + mole aceticacid ∈ L 2 2

REERENCES'

+ama*oss -., 1A

-a*hiyar ".@., "ha7ore :.9. 201>. +ecovery o& ?cetic ?ci* &rom C&&luent via Free6e @rystalli6ation. nternational Journal o& :cienti&ic Cn$ineerin$ an* "echnolo$y.