Esterification : continuous noncatalytic production of lower acetates
by John A Runberg
A THESIS Submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree
of Master of Science in Chemical Engineering at Montana State College
Montana State University
© Copyright by John A Runberg (1950)
Abstract:
The use of increased temperature obtained by rectifying at super-atmospheric pressure was investigated
as a means of carrying out the continuous non-catalytic esterification of the lower alcohols with acetic
acid.
The non-catalytic esterification rate at the boiling point at 60 psig pressure was determined for ethyl,
n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, n-amyl, and sec-amyl alcohols with acetic acid.
The ternary azeotrope composition at 60 psig pressure was determined for each acetate system and a
continuous non-catalytic esterification carried out for each ester.
It was found that continuous non-catalytic esterification could be successfully carried out at 60 psig
pressure for each ester studied except methyl acetate which formed no ternary azeotrope and tert-butyl
and tert-amyl acetates which formed at too slow a rate. ESTERIFICATION - CONTINUOUS NONCATALYTIC
PRODUCTION OF LOWER ACETATES
by
JOHN A. RUNBERG
A THESIS
S u b m itte d t o th e G rad u ate F a c u lty
in
p a r t i a l f u l f i l l m e n t o f th e r e q u ir e m e n ts
f o r th e d e g re e o f
M a ste r o f S c ie n c e i n C hem ical E n g in e e r in g
at
M ontana S t a t e C o lle g e
A p p ro v ed :
H ead, M a jo r/Departm e:
C hairm an
lin in g C o W itte e
D ean, G ra d u a te D iv is io n
Bozeman, M ontana
A ugust 1950
A /3 7 /
2
TABLE OF CONTENTS
page
A b s t r a c t . ................................. .... ...............................................................................
I
I n t r o d u c t i o n .......................................................................................................
3
4
II
E q u ip m en t, P r o c e d u re s and M a t e r i a l s ......................................... .
6
A, E quipm ent.........................................................................................
6
B, P r o c e d u r e s ....................................................................................
8
C, M a t e r i a l s ..........................................................................................11
III
Sample C a l c u l a t i o n s ........................................................................................... 12
17
V
VI
V II
R e s u lt s .....................................
14
S u m m ary ..................................................
16
L i t e r a t u r e C it e d ..................................................................................................... 17
A ppendix..............................................................................................................
9 5 1 2 2
18
3
ABSTRACT
The u s e o f in c r e a s e d te m p e ra tu re o b ta in e d by r e c t i f y i n g a t s u p e r a tm o s p h e ric p r e s s u r e was i n v e s t i g a t e d a s a means o f c a r r y i n g o u t th e
c o n tin u o u s n o n - c a t a l y t i c e s t e r i f i c a t i o n o f th e lo w er a l c o h o ls w ith
a c e tic a c id .
The n o n - c a t a l y t i c e s t e r i f i c a t i o n r a t e a t th e b o i l i n g p o in t a t
60 p s i g p r e s s u r e was d e te rm in e d f o r e t h y l , n - p r o p y l, i s o - p r o p y l , n - b u t y l ,
i s o - b u t y l , s e c - b u t y l , n -a m y l, and se c -a m y l a lc o h o ls w ith a c e t i c a c i d .
The t e r n a r y a z e o tr o p e c o m p o sitio n a t 60 p s i g p r e s s u r e was d e te rm in e d f o r
ea c h a c e t a t e sy ste m and a c o n tin u o u s n o n - c a t a l y t i c e s t e r i f i c a t i o n
c a rrie d o u t fo r each e s t e r .
I t was fou n d t h a t c o n tin u o u s n o n - c a t a l y t i c e s t e r i f i c a t i o n co u ld
be s u c c e s s f u l l y c a r r i e d o u t a t 60 p s i g p r e s s u r e f o r e a c h e s t e r s tu d ie d
e x c e p t m e th y l a c e t a t e w h ich form ed no t e r n a r y a z e o tro p e and t e r t - b u t y l
and t e r t -am yl a c e t a t e s w h ich form ed a t to o slow a r a t e .
4
I INTRODUCTION
In th e com m ercial p r e p a r a t i o n o f e s t e r s fro m th e lo w e r a lc o h o ls and
o r g a n ic a c i d s th e e s t e r i f i c a t i o n r e a c t i o n i s i n v a r i a b l y c a r r i e d o u t in
th e p re s e n c e o f a c a t a l y s t .
The e s t e r i f i c a t i o n i s u s u a l l y acc o m p lish e d
by h e a t in g t o th e b o i l i n g p o in t a m ix tu re o f a l c o h o l, o r g a n ic a c i d , and
c a ta ly s t.
The e s t e r i s u s u a l l y s e p a r a t e d by r e c t i f i c a t i o n a s f a s t a s
i t i s fo rm ed .
I n th e a b sen ce o f a c a t a l y s t , e x c e p t in t h e c a s e o f a
h ig h b o i l i n g a lc o h o l w ith a h ig h b o i l i n g a c i d , e s t e r i f i c a t i o n ca n n o t be
e f f e c t e d by b o i l i n g a t a tm o s p h e ric p r e s s u r e in a r e a s o n a b le tim e w ith o u t
some o t h e r means o f s p e e d in g up th e r e a c t i o n .
The e s t e r i f i c a t i o n r a t e s
e x p r e s s e d a s p e r c e n t c o n v e rs io n p e r h o u r o f th e lo w er a l c o h o ls w ith
a c e t i c a c id a t t h e i r a tm o s p h e ric b o i l i n g p o i n t s , a r e g iv e n in T ab le I I I .
E s t e r i f i c a t i o n in th e a b se n c e o f a c a t a l y s t w ould have some d i s t i n c t
a d v a n ta g e s .
In g e n e r a l p r a c t i c e h y d r o c h lo r ic and s u l f u r i c a c i d s a r e th e
m ost commonly u se d c a t a l y s t s , th e l a t t e r in m ost co m m ercial p l a n t s b e c a u se
o f i t s ch eap n ess.
B oth a c i d s a r e c o r r o s iv e on m e ta ls and s u l f u r i c a c id
may cau se d e h y d r a tio n o f an a lc o h o l i f u se d in to o g r e a t an amount o r a t
to o h ig h a te m p e r a tu r e . ( 2 )
I t i s w e ll known t h a t th e r a t e o f n o n c a t a l y t i c e s t e r i f i c a t i o n
in c r e a s e s r a p i d l y w ith te m p e r a t u r e , d o u b lin g w ith e a c h 1 5 -2 5 0Co r i s e in
te m p e r a tu r e .
The e s t e r i f i c a t i o n r a t e s a t 155°C. (4 ) a r e com pared to th e
r a t e s a t th e a tm o s p h e ric b o i l i n g p o in t i n T a b le I I I .
a r e fro m th e w ork o f M en sch u tk in ( 4 ) .
The r a t e s a t IS S 0C6
He s e a le d e q u a l mol p o r t i o n s o f
a l c o h o ls and a c e t i c a c id in g l a s s tu b e s an d h e a te d them t o IS S 0C6 f o r one
5
h o u r.
The u n r e a c te d a c i d was th e n t i t r a t e d and th e p e r c e n t e s t e r i f i c a ­
tio n c a lc u la te d .
I f th e r e a c t i o n can be e f f e c t e d a t a s u f f i c i e n t l y h ig h
te m p e r a tu r e , a s a t i s f a c t o r y r a t e can be o b ta in e d in th e a b se n c e o f any
c a ta ly s t.
A s u i t a b l e te m p e r a tu r e may be o b ta in e d by c a r r y i n g o u t th e
e s t e r i f i c a t i o n in a r e c t i f i c a t i o n column o p e r a te d u n d er s u f f i c i e n t p r e s s u r e
t o g iv e th e d e s ir e d b o i l i n g te m p e r a tu r e .
The e s t e r i s u s u a l l y removed fro m t h e r e a c t i o n m ix tu re in th e form
o f a t e r n a r y c o n s ta n t b o i l i n g m ix tu r e .
e s t e r , and w a te r .
The t e r n a r y c o n s i s t s o f a l c o h o l,
In o r d e r t o c a r r y o u t th e r e a c t i o n c o n tin u o u s ly , th e
f e e d m ust c o n t a in in a d d i t i o n to a mol o f a lc o h o l p e r mol o f a c i d , one
o r more o f th e com ponents o f th e t e r n a r y i n o r d e r t h a t no com ponent b u i l d
up a s e x c e s s in th e s t i l l p o t.
The r e s e a r c h n e c e s s a r y b e f o r e any c o n tin u o u s e s t e r i f i c a t i o n can be
c a r r i e d o u t by th e p ro p o se d m ethod in v o lv e s th e d e te r m in a tio n o f a
te m p e ra tu re and p r e s s u r e a t w hich th e e s t e r i f i c a t i o n r a t e i s s u f f i c i e n t l y
h ig h , and th e d e te r m in a tio n o f th e c o m p o s itio n o f th e lo w e s t b o i l i n g
t e r n a r y a z e o tr o p e a t t h a t p r e s s u r e .
I t was th e p u rp o se o f t h i s w ork t o d e te r m in e : I - th e n o n - c a t a l y t i c
e s t e r i f i c a t i o n r a t e a t th e b o i l i n g te m p e r a tu r e c o rre s p o n d in g t o 60 p s ig
p r e s s u r e o f m e th y l, e t h y l , n - p r o p y l, i s o - p r o p y l , n - b u t y l , i s o - b u t y l ,
s e c - b u t y l , t e r t - b u t y l , n -a m y l, is o - a m y l, and t e r t - a m y l a l c o h o ls w ith
a c e t i c a c i d : 2 - th e c o m p o s itio n o f th e c o rre s p o n d in g t e r n a r y a z e o tro p e
form ed f o r e a c h o f th e s e a t th e te m p e r a tu r e and p r e s s u r e u se d in I ; and
5a
3 - make up a ch a rg e in th e c o r r e c t p r o p o r ti o n s and o p e r a te th e e s t e r i f i c a ­
t i o n p r o c e s s c o n tin u o u s ly f o r e a c h o f th e sy stem s named above a t th e
p re ssu re s e le c te d .
6
I I EQUIPMENT, PROCEDURES AND MATERIALS
A. EQUIPMENT
The equipm ent u se d in t h i s i n v e s t i g a t i o n c o n s is te d o f a p r e s s u r iz e d
e s t e r i f i c a t i o n u n i t , shown in F ig u r e I ; a g l a s s p r e c i s i o n colum n, and a
t o t a l r e f l u x sy ste m .
The p r e s s u r i z e d e s t e r i f i c a t i o n u n i t c o n s is te d o f a c o p p e r p r e c i s i o n
column s i m i l a r to a g l a s s l a b o r a t o r y colum n.
The in s id e d ia m e te r o f th e
column was I l / 4 - i n c h e s and a s e c t i o n 5 2 - in c h e s lo n g was packed w ith 1 / 4 in c h g l a s s - h e l i c e s .
The s t i l l p o t was c o n s tr u c t e d from a s t a i n l e s s s t e e l
oxygen ta n k w ith a d a p a c ity o f a b o u t 1800 m l. s i l v e r s o ld e r e d t o th e co p p e r
colum n.
The c o p p e r column was ja c k e te d by 48 mm, g l a s s tu b in g in s id e 54 mm.
g l a s s tu b in g w ith a h e a t in g c o i l s p i r a l i n g th e le n g th o f th e in s id e tu b e .
Power was s u p p lie d t o th e h e a t in g e le m e n t th r o u g h an a u t o tr a n s f o r m e r .
The
c o n d e n s e r s e c t i o n c o n s is te d o f a w a te r ja c k e t c o n s tr u c te d o f an 11- in c h
s e c t i o n o f tw o - in c h s ta n d a r d ir o n p ip e and a c o ld f i n g e r 12- in c h e s lo n g
c o n s tr u c t e d o f 1 / 2 - in c h co p p e r tu b in g ( I ) .
The flo w o f w a te r tliro u g h th e
c o ld f i n g e r was c o n t r o l l e d by u s in g a l a b o r a t o r y b e llo w s pump s u p p lie d
fro m a c o n s ta n t head s o u r c e .
The r e f l u x r a t i o o b ta in e d i n th e co ld f i n g e r
ty p e c o n d e n sin g head c o u ld n o t be m easured b u t was e s tim a te d t o be in th e
ra n g e o f from 5 -1 t o 1 0 -1 .
C onnected t o th e s t i l l p o t and a l s o c a p a b le o f b e in g p r e s s u r iz e d
was a c o p p e r fe e d ta n k w ith a c a p a c it y o f ab o u t 5000 m l.
A p r e s s u r iz e d
r e c e i v e r c o n s tr u c t e d o f I l / 2- in c h s ta n d a r d ir o n p ip e c o m p lete d th e u n i t
m aking i t p o s s i b le t o ru n th e sy ste m c o n tin u o u s ly w h ile u n d e r p r e s s u r e .
7
The u n i t was k e p t u n d e r th e d e s i r e d p r e s s u r e by means o f an a i r co m p resso r
and a D e V ilb is s P r e s s u r e R e g u la to r .
A 1 1 0 - v o lt 5 5 0 -w a tt h e a t e r c o n t r o l l e d
by an a u to tr a n s f o r m e r s u p p lie d th e h e a t t o th e s t i l l p o t.
A g l a s s p r e c i s i o n colum n, o n e -in c h in d ia m e te r w ith a 3 6 - in c h s e c t i o n
pack ed w ith 1/ 4- in c h g l a s s - h e l i c e s and eq u ip p e d w ith a Corad ty p e co n d e n sin g
head was u s e d t o make a tm o s p h e ric s e p a r a t i o n s .
The equip m en t u sed to d e te rm in e th e e s t e r i f i c a t i o n r a t e a t a tm o s p h e ric
p r e s s u r e c o n s is te d o f a 250 m l. E rlen m ey e r f l a s k , a p y re x g la s s L ie b ig
c o n d e n s e r, a 1 1 0 - v o lt 5 5 0 -w a tt h e a t e r c o n t r o l l e d by an a u to tr a n s f o r m e r , an
ic e b a t h , and a 50 m l. b u r e t .
8
B. PROCEDURES
TERNARY AZEOTROPE COMPOSITION UNDER 60 PSIG PRESSURE:
As a f i r s t
a p p ro x im a tio n i t was assum ed t h a t th e t e r n a r y a z e o tr o p e c o m p o sitio n u n d e r
60 p s i g p r e s s u r e w ould be th e same a s a t a tm o s p h e ric p r e s s u r e .
From th e
a tm o s p h e ric t e r n a r y c o m p o s itio n d a t a , T a b le I ( 3 ) , th e p r o p o r ti o n s o f
a lc o h o l and a c i d , and w a te r i f n e c e s s a r y , r e q u ir e d t o fo rm th e t e r n a r y
a z e o tro p e w ere c a l c u l a t e d .
About 1000 m l. o f t h i s m ix tu re was th e n
c h a rg e d to th e u n i t and b o il e d u n d e r 60 p s i g p r e s s u r e a t t o t a l r e f l u x f o r
one h o u r.
P ro d u c t was th e n ta k e n o f f a t a h ig h r e f l u x r a t i o u n t i l th e
te m p e ra tu re in th e s t i l l p o t b eg an to clim b i n d i c a t i n g e x h a u s tio n o f th e
t e r n a r y a z e o tr o p e .
The p ro d u c t was th e n r e d i s t i l l e d in th e g l a s s p r e c i s i o n column u n d e r
a tm o s p h e ric p r e s s u r e .
The a tm o s p h e ric t e r n a r y a z e o tro p e w ould come o f f
f i r s t and c o n tin u e t o come o f f u n t i l one o f th e c o n s t i t u e n t s o f th e t e r n a r y
was e x h a u s te d from th e c h a rg e .
The n e x t h ig h e r b o i l i n g a z e o tr o p e , alw ay s
a b in a r y , w ould th e n come o f f u n t i l one o r b o th o f i t s c o n s t i t u e n t s w ere
e x h a u s te d .
Any m a t e r i a l re m a in in g w ould be one o f th e th r e o o r i g i n a l
c o n s t i t u e n t s o f th e t e r n a r y .
By d e te r m in in g th e amount and c o m p o sitio n
o f e a c h f r a c t i o n th e c o m p o s itio n o f th e t e r n a r y o b ta in e d u n d e r 60 p s ig
p r e s s u r e c o u ld th e n be c a l c u l a t e d .
T h is p ro c e d u re was th e n r e p e a te d u s in g th e t e r n a r y a z e o tr o p e com posi­
t i o n d e te rm in e d above a s a b a s i s f o r th e p r o p e r fe e d c o m p o s itio n .
p s i g t e r n a r y a z e o tr o p e th u s o b ta in e d was a n a ly z e d a s a b o v e .
The 60
I f th e t e r n a r y
a z e o tro p e o b ta in e d fro m th e second d e te r m in a tio n was a p p ro x im a te ly th e same
9
a s t h a t from th e f i r s t d e t e r m in a tio n i t was assumed to be th e c o r r e c t
60 p s i g t e r n a r y a z e o tr o p e , i f n o t a n o th e r d e te r m in a tio n was made.
ESTSRIFICATION RATE UIiDER 60 PSIG PRESSURE:
The p r o p e r f e e d ch arg e
f o r c o n tin u o u s o p e r a t io n was c a l c u l a t e d fro m th e f i n a l 60 p s ig t e r n a r y
a z e o tro p e c o m p o s itio n .
A l a r g e b a tc h o f fe e d was p re p a re d and th e u n i t
was o p e ra te d c o n tin u o u s ly f o r 30 t o 40 h o u r s .
The u n i t was o p e r a te d a t
d e c r e a s in g r e f l u x r a t i o s t o d e te rm in e how f a s t p ro d u c t c o u ld be removed
w ith o u t r e s u l t i n g in a te m p e ra tu re r i s e
in th e h ead .
The p ro d u c t ta k e n
o f f e a c h h o u r was w eighed and by k e e p in g th e amount o f c h a rg e in th e s t i l l
p o t a p p ro x im a te ly c o n s ta n t th e p e r c e n t o f ch a rg e removed p e r h o u r co u ld
be c a l c u l a t e d .
An e s ti m a t e o f th e r a t e o f e s t e r i f i c a t i o n u n d e r o p e r a tin g
c o n d i tio n s was th u s o b ta in e d .
T h is may n o t be th e maximum e s t e r i f i c a t i o n
r a t e u n d e r th e o p e r a t in g c o n d i tio n s b e c a u se th e c a p a c it y o f th e column
may have b een re a c h e d b e f o r e th e r a t e o f t a k e - o f f e q u a le d th e r a t e o f
e s te rific a tio n .
The 30 t o 40 h o u r r u n a l s o s e rv e d a s a ch eck on th e f e e d c o m p o s itio n .
I f th e r e was a b u il d - u p o f any com ponent i n th e s t i l l p o t i t in d ic a te d
t h a t th e fe e d c o m p o s itio n was i n c o r r e c t .
In th e c a s e o f e t h y l , n - p r o p y l, and is o - p r o p y l a l c o h o l s , th e fe e d
was o f one p h a se and c o u ld be a d m itte d t o th e s t i l l p o t c o n tin u o u s ly by
a d j u s t i n g th e v a lv e on th e f e e d t a n k .
In th e case o f th e h ig h e r a lc o h o ls
th e f e e d was two p h a s e s and was added in s m a ll b a tc h e s so t h a t th e
o p e r a t io n was a p p r o x im a te ly c o n tin u o u s .
10
ESTERIFICATION RATE AT ATMOSPHERIC PRESSURE:
To d e te rm in e th e r a t e
o f e s t e r i f i c a t i o n a t th e b o i l i n g p o in t u n d e r a tm o s p h e ric p r e s s u r e e q u a l
mol p o r t i o n s o f a lc o h o l and a c e t i c a c id w ere p la c e d in an E rlen m ey e r f l a s k
and b o ile d a t t o t a l r e f l u x u s in g a p y re x g l a s s L ie b ig c o n c e n s e r s e t i n a
v e r t i c a l p o s itio n .
A f te r b o i l i n g f o r one h o u r th e f l a s k was p la c e d in an
ic e b a th and th e u n r e a c te d a c i d was t i t r a t e d w ith a s ta n d a r d s o l u t i o n o f
sodium h y d ro x id e u s in g phenoI p h t h a l e in a s th e i n d i c a t o r .
e s t e r i f i c a t i o n c o u ld th e n be c a l c u l a t e d .
The p e r c e n t o f
11
C. MATERIALS
The a c e t i c a c id u se d i n t h i s i n v e s t i g a t i o n was c . p . g ra d e o b ta in e d
fro m M erck and Company I n c .
The a l c o h o ls u sed w ere c . p . g ra d e o b ta in e d from S h a r p ie s , Eim er and
Amend, and Eastm an Kodak.
12
III
SAMPLE CALCULATIONS
C a l c u la t io n s of f ood c h a rg e on th e b a s i s o f th e a tm o s p h e ric p r e s s u r e
t e r n a r y , t e r n a r y c o m p o s itio n a t 60 p a Ig p r e s s u r e , and f e e d ch a rg e b ased
on th e t e r n a r y a t 60 p s i g p r e s s u r e f o r n -am y l a c e t a t e a r e p r e s e n te d a s
t y p i c a l f o r a l l a c e t a t e s p ro d u c e d .
A.
C a l c u la t io n o f fe e d c h a rg e on th e b a s i s o f th e a tm o s p h e ric
te rn a ry :
E s te r
W eight p e r c e n t
A lc o h o l
W ater
3 3 .3
5 6 .2
18
1 0 .5
Mol w e ig h t
1 3 0 .2
8 8 .1 5
Mols
.0806
.3 7 8
Mols
I
3 .1 2
4 .6 8
3 8 .7
F eed Charge
Mols
I
60
A lco h o l
4 .6 8 + I
500
W ater
3 8 .7 " I
678
A cid
B.
Grams
C a l c u la t io n o f t e r n a r y c o m p o s itio n u n d e r 60 p s i g p r e s s u r e :
A n a ly s is o f th e t e r n a r y p ro d u c t u n d e r 60 p s ig p r e s s u r e was
44, 7^ a tm o s p h e ric t e r n a r y (10.5% e s t e r , 33.3% a l c o h o l , and
56.2% w a t e r ) , 40.3% b in a r y (46% a lc o h o l and 54% w a t e r ) , and
15% w a te r .
13
E s te r
A lco h o l
W ater
Atm. t e r n a r y
4 .7
1 4 .9
2 5 .1
A-W b in a r y
O
1 8 .6
2 1 .7
W ater
O
O
1 5 .0
60 p s i g t e r n a r y
4 .7
3 3 .5
6 1 .8
C a l c u la t io n o f f e e d ch arg e on b a s i s o f 60 p s ig t e r n a r y :
W eight p e r c e n t
E s te r
A lco h o l
W ater
4 .7
3 3 .5
6 1 .8
18
Mol w e ig h t
1 3 0 .2
8 8 .1 5
Mols
.0 3 6 1
.3 3 0
M ols
I
1 0 .5 2
3 .4 :
95
Feed Charge
Ivlols
A cid
A lco h o l
W ater
I
Grains
60
1 0 .5 2 + I
1015
95-1
1690
14
IW RESULTS
I t was d e c e id e d t o o p s r a ta th o u n i t u n d e r a p r e s s u r e o f 60 p s ig s in c e
t h i s w ould g iv e a s u b s t a n t i a l te m p e r a tu r e r i s e com pared t o th e a tm o s p h e ric
b o i l i n g p o i n t s and was a b o u t th e maximum p r e s s u r e a t w hich th e equipm ent
u se d c o u ld be o p e r a te d .
The l i t e r a t u r e
i n d i c a t e s t h a t t h e r e i s no t e r n a r y a z e o tr o p e form ed by
m e th y l a l c o h o l , m e th y l a c e t a t e , and w a te r and a l s o i n d i c a t e s t h a t th e
lo w e s t b o i l i n g b i n a r y a z e o tr o p e i s composed o f m e th y l a lc o h o l and m eth y l
a c e ta te .
T h e r e f o r e , th e e s t e r i f i c a t i o n m ethod p ro p o se d c o u ld n o t be
o p e ra te d c o n tin u o u s ly s in c e t h e r e w ould be no method o f c a r r y i n g o f f th e
w a te r form ed in th e e s t e r i f i c a t i o n r e a c t i o n .
On th e ch an ce t h a t th e r e
m ig h t be a t e r n a r y a z e o tr o p e a t a p r e s s u r e o f 60 p s i g , a m ix tu re o f a c e t i c
a c id and m eth y l a lc o h o l b a s e d on th e a l c o h o l - e s t e r b in a r y a z e o tr o p e was
fe d to th e u n i t .
The p ro d u c t was a n a ly z e d a n d , a s a t a tm o s p h e ric p r e s s u r e ,
th e lo w e s t b o i l i n g a z e o tr o p e was th e a lc o h o l e s t e r b in a r y .
The e s t e r i f i c a t i o n o f e t h y l a lc o h o l w ith a c e t i c a c id u n d e r a p r e s s u r e
o f 60 p s i g r e s u l t e d i n a t e r n a r y a z e o tr o p e b o i l i n g a t IEO0O, and c o n s i s t i n g
o f 3 6 .7 p e r cen t a l c o h o l , 5 6 .6 p e r c e n t e t h y l a c e t a t e , and 6 .7 p a r c e n t
w a te r .
T h u s, th e t e r n a r y a z e o tr o p e w ould remove o n ly 58 p e r c e n t o f th e
w a te r form ed by th e e s t e r i f i c a t i o n r e a c t i o n .
To make th e o p e r a tio n
c o n tin u o u s i t was n e c e s s a r y to add enough an h y d ro u s e t h y l a c e t a t e and
e x t r a e t h y l a l c o h o l t o th e f e e d t o fo rm th e t e r n a r y a z e o tr o p e w ith th e
re m a in in g 43 p e r c e n t w a te r .
The fe e d c o m p o sitio n f o r c o n tin u o u s
o p e r a t io n i s g iv e n in T a b le IV".
D u rin g a lo n g ru n b a se d on t h i s fe e d
15
c o m p o s itio n 4291 gram s were fe d to th e u n i t .
P ro d u c t was rem oved a t a
r a t e a s h ig h a s 2 7 .3 p e r c e n t
o f th e s t i l l p o t ch arg e p e r h o u r w ith o u t
any b u i l d up o f any com ponent
o r an y te m p e ra tu re r i s e .
A n a ly s is l i s t e d
in T a b le s I , I I , and I I I a r e in w e ig h t p e r c e n t .
The e s t e r i f i c a t i o n o f n - p r o p y l, is o - p r o p y l , n - b u t y l , i s o - b u t y l ,
s e c - b u t y l , n -a m y l, and s e c -a m y l a l c o h o ls w ith a c e t i c a c id u n d e r 60 p s ig
p r e s s u r e r e s u l t e d i n t e r n a r y a z e o tr o p e s o f th e c o m p o sitio n s g iv e in T able
II.
In e a c h c a se th e t e r n a r y a z e o tro p e w ould remove a l l th e w a te r
form ed by th e e s t e r i f i c a t i o n r e a c t i o n , and in o r d e r t h a t th e p r o d u c t from
th e s t i l l c o rre s p o n d w ith th e t e r n a r y a z e o tr o p e c o m p o s itio n , an e x c e s s o f
a lc o h o l and w a te r had t o be added t o th e f e e d .
e a c h e s t e r i f i c a t i o n w ith fe e d
Long ru n s wore made f o r
a t th e c o m p o sitio n g iv e n in T a b le BT and
in e a c h c a se p ro d u c t was rem oved a t th e maximum r a t e i n d i c a te d in
T a b le I I I .
I n th e c a s e o f b o th t o r t - b u t y l and t a r t- a m y l a l c o h o ls w ith a c e t i c
a c id th e e s t e r i f i c a t i o n r a t e was so slo w t h a t a r e f l u x r a t i o h ig h enough
t o keep th e te m p e r a tu r e c o n s ta n t c o u ld n o t be m a in ta in e d ,
sfhen a s m a ll
am ount o f p r o d u c t was w ith d raw n th e h ead te m p e r a tu r e would im m ed iately
b e g in t o r i s e .
The r a t e s o f e s t e r i f i c a t i o n a t th e a tm o s p h e ric b o i l i n g p o i n t s g iv e n
in T a b le I I I were c a l c u l a t e d from e x p e r im e n ta l d a t a .
16
V SUMMARY
The f o llo w in g summary may be draw n from th e r e s u l t s fo u n d in t h i s
in v e s tig a tio n :
1.
E s t e r i f i c a t i o n o f th e lo w e r a lc o h o ls by a c e t i c a c i d , w ith
th e e x c e p tio n o f m e th y l a l c o h o l , n a y be c a r r i e d o u t
c o n tin u o u s ly in th e ab sen ce o f a c a t a l y s t in a r e c t i f i c a t i o n
column u n d e r p r e s s u r e .
2.
I n a l l c a s e s th e t e r n a r y a z e o tr o p e c o m p o sitio n a t 60 p s ig
p r e s s u r e i s d i f f e r e n t fro m t h a t a t a tm o s p h e ric p r e s s u r e .
3.
In a l l c a s e s th e p e r c e n t e s t e r i n th e t e r n a r y a z e o tr o p e
i s l e s s a t 60 p s i g p r e s s u r e th a n a t a tm o s p h e ric p r e s s u r e .
17
VI LITERATURE: CITED
(I)
B arg and S m ith , I n d u s t r i a l E n g in e e rin g Chem.
(2 )
G ro g g in s , P .H . UNIT PROCESSES IN ORGANIC SYNTHESIS,
3 rd Ed. p . 625. New Y ork, M cG raw -H ill Book Co. I n c . 1947.
(3 )
H o r s le y , L .H . T a b le o f A z e tro p e s and N o n a z e o tro p e s,
ANALYTICAL CHEMISTRY, 1 9 , 5 0 8 -6 0 0 (1947)
(4 )
M e n sc h u tk in . A n n ., 195, 334 (1 8 7 9 ); 197, 193 (1 8 7 9 );
B e r ., 1 3 , 162 (1 8 8 0 ); Ann. chim . ( 5 ) , 2 3 , 14 (1 8 8 1 );
3 0 , 81 (1 8 8 3 ); Z. p h y s ik . Chem., I , 611 (1 8 8 7 );
9 , 237 (1 8 9 2 ); B e r . , 4 2 , 4020 (1 9 0 9 ).
18
V II
APPENDIX
page
F ig u re I
- S ch em atic D iagram o f E q u ip m e n t...........................
19
T a b le
I
- A tm o sp h eric A z eo tro p e C o m p o s i t i o n s .......................................
20
T a b le
II
- 60 p s i g T e rn a ry A zeo tro p e C o m p o s itio n s ................................
21
T a b le
I I I - E s t e r i f i c a t i o n R a te s ............ ...................................................
22
T ab le
TV
23
- F eed C o m p o sitio n s f o r C o n tin u o u s O p e ra tio n ............ ..
19
Ht O
u_gC0LD
FINGER
PRESSURE
REGULATOR
l/l" COPPER
TUBl NG
SARAN
SIGHT
TUBE
SARAN
SIGHT
TUBE
4 GLASS
HELICES
FEED
TANK
GLASS
JACKETS
DRAIN
F ig u re I
l / i ' COPPER
TUBING
S ch em atic D iagram o f Equipm ent
Table I
ATLlCXSrHESIC AESOTROFE COMPOSITIONS
&
B .P.
°C .
!.fethyl A c e ta te
5 7 .1
5 6 .5
3 .5
E th y l A c e ta te
7 7 .1
7 0 .4 5
8. 6
101.6
8 2 .4
9 1 .0
n - B u ty l A c e ta te
£
T e rn a ry
%
A
O to
S s te r
A-41
E“ W B in a r ie s
>
B .P .
B .P .
%
0C.
W
0C.
W
5 4 .0
1 8 .5
B .P .
0C.
S
A
%
W
Ho te r n a r y
7 8 .1 5
4 .4
7 1 .3
3 0 .6
7 0 .3
8 3 .2
9 .0
7 .8
1 2 .5
8 7 .7
2 8 .3
9 4 .2
40
8 2 .2
5 9 .5 1 9 .5
21.0
7 7 .4
6.2
8 0 .4
12.1
8 1 .3
60
7 6 .2
6 3 .7 2 6 .2
10.1
1 2 5 .1
9 0 .2
2 6 .7
9 2 .4
3 8 .0
1 1 7 .2
47
8 9 .4
3 5 .3 2 7 .4
3 7 .3
i s o -B u ty l A c e ta te
1 1 6 .3
8 7 .5
1 9 .5
8 9 .9
3 3 .0
8 7 .4
1 6 .6
86.8
4 6 .5 2 3 .1
3 0 .4
s e o -B u ty l A c e ta te
112
86.6
1 9 .4
8 8 .5
3 2 .0
9 9 .6
1 3 .7
86.0
32
23
no d a te
7 9 .9
11.8
no d a t a
n -iT o p y l A c e ta te
I s o - P r o p y l A c e ta te
t e r t - B u ty l A c e ta te
96
45
no d a ta
n -A cy l A c e ta te
148
9 5 .2
41
9 5 .9
54
no a z e o .
9 4 .8
1 0 .5 3 3 .3
5 6 .2
Is o -A n y l A c e ta te
139
9 3 .8
3 6 .2
9 5 .2
4 9 .6
no a z e o .
9 3 .6
24
4 4 .8
t e r t - A n y l A c e ta te
no d a ta
S- S s te r
A- A lco h o l
W- W ater
3 1 .2
21
T a b le I I
60 PSIG TERNARY AZEOTROPES
E s te r
B .P.
1C.
^ A lc o h o l
'yoEster
% ,,'ater
No t e r n a r y
M ethyl A c e ta te
E th y l A c e ta te
120
3 6 .7
5 5 .6
6 .7
n -P ro p y l A c e ta te
127
5 7 .9
2 3 .0
1 9 .1
I s o - P r o p y l A c e ta te
122
6 0 .8
2 8 .0
11.2
n - B u ty l A c e ta te
135
4 7 .1
1 5 .2
3 7 .8
I s o - B u ty l A c e ta te
133
4 1 .6
2 6 .9
3 1 .5
s e c - B u ty l A c e ta te
133
6 3 .4
6 .4
3 0 .2
3 3 .5
4 .7
6 1 .8
3 9 .9
1 3 .2
4 6 .9
No d a ta
t e r t - B u ty l A c e ta te
n -A uyl A c e ta te
142
Is o -A u y l A c e ta te
140
t e r t -Amyl A c e ta te
I
No d a ta
22
T a b le I I I
ESTERIFICATION RATES
E s te r
A tm o sp h eric R a te
Temp. 0C.
R ate
155°C. R ate
60 PSIO R ate
Temp. 0C. R ate
Ltothyl A c e ta te
62
1 0 .9 0
5 5 .6 0
E th y l A c e ta te
77
8 .7 3
4 6 .9 5
133
2 7 .3
n-I-T opyl A c e ta te
95
9 .7 0
4 6 .9 2
140
2 8 .6
Is o -R ro p y l A c e ta te
82
2.20
2 6 .5 3
136
2 3 .0
101
1 4 .3 5
4 6 .8 5
145
2 6 .0
is o - D u ty l A c e ta te
98
11 .7 5
4 4 .3 6
143
2 0 .4
s e c - B u ty l A c e ta te
97
4 .3 0
2 2 .5 9
144
10.2
t e r t - B u ty l A c e ta te
87
0.22
n-Amyl A c e ta te
104
1 3 .0 0
150
1 9 .7
iso-A rayl A c e ta te
103
1 1 .3 5
148
1 7 .8
95
None
n -D u ty l A c e ta te
t e r t -Arayl A c e ta te
1 .4 3 .
23
Table IV
FSED CGLlPOSITICN FOR CONTINUOUS OPERATION
E a te r
IuBthyl A c e ta te
,oAcid
,"A lcohol
vjv/ater
,ZEeter
C o n tin u o u s o p e r a t io n n o t p o s s ib le
E th y l A c e ta te
2 2 .4
5 3 .8
O
I s o - P r o p y l A c e ta te
1 6 .7
7 7 .6
5 .7
O
n -P ro p y l A c e ta te
1 3 .5
7 1 .5
1 5 .0
O
n -B u ty l A c e ta te
7 .9
5 6 .7
3 5 .4
O
is o - B u ty l A c e ta te
1 3 .9
5 8 .7
2 7 .4
O
s e c -B u ty l A c e ta te
3 .3
6 7 .4
2 9 .3
O
t a r t - B u t y l A c e ta te
—
—
n-A nyl A c e ta te
2.2
3 6 .7
6 1 .1
O
i eo-Amyl A c e ta te
6.1
4 9 ,0
4 4 .9
O
t e r t -A nyl A c e ta te
——
—
9 5 1 2 8
——
——
2 3 .8
-
-
MONTANA CTATr- i..,. .___
3 1762 10015397 O
^378
H?66e
Qc-i pp
cop.2
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ncatalytic' production of I o w e ?
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JJ aji/t
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