Separation of Phthalic Anhydride
Transcript of Separation of Phthalic Anhydride
-
8/11/2019 Separation of Phthalic Anhydride
1/2
P a t e n t e d
O c t . 2 9 ,
1 9 4 0
U N I T E D S T A T E S
* 2 , 2 2 0 , 0 4 4
PATENT OFFICE
2 , 2 2 0 , 0 4 4
SEPARATION OF ALEIC AND HTHALIC
ANHYDRIDE
A l p h o n s
0 . J a e g e r , G r e e n w i c h ,
C o n n . ,
a s s i g n o r
t i
American Cyanamid'& C h e m i c a l C o r p o r a t i o n ,
New
o r k ,
N .
Y . , ' a
c o r p o r a t i o n
o f Delaware
N
Drawing. A p p l i c a t i o n September , 1 9 3 9 ,
.
Serial
No. 293,619
3 C l a i m s .
T h i s
i n v e n t i o n r e l a t e s
t o
t h e
p r o d u c t i o n
and
recovery
o f
maleic a c i d o r
anhydride
f r o m
the
c a t a l y t i c oxidation o f
org anic c o m p o u n d s
in
which maleic
anhydride
i s
obtained
a s
a by
5 product _
In
t h e c a t a l y t i c v a p o r phase
o x i d a t i o n
o f
n a p h
thalene t o
p h t h a l i c a n h y d r i d e ,
a
g r e a t e r o r
l e s s
a m o u n t
o f
maleic
anhydride i s
produced a s
a by
product
a n d f
t h e
naphthalene s admix ed
with
1 0 p h e n o l s ,
wood
a r , b e n z o i c a c i d , b e n z e n e , f u r f u r a l ,
t h i o p h e n e , t e r p e n e s , c y c l o p e n t a d i e n e o r o t h e r ,
compounds c o n t a i n i n g
u n s a t u r a t e d
l i n k a g e s ,
l a r g e r
amounts
o f m a l e i c anhydride a r e p r o
d u c e d .
S i m i l a r l y ,
i f t h e naphthalene s o m i t t e d ,
1 5
m a l e i c
anhydrideis produced
a s
o n e
o f
t h e
prod
u c t s
although i n
somewhat
s m a l l e r
y i e l d s .
In
the g a s e s c o m i n g f r o m the
v a p o r
phase con
v e r t e r , t h e m a l e i c a c i d , o f c o u r s e ,
i s
p r e s e n t
mainly i n
t h e
fo r m o f t h e anhydride which s a
2 0 v e r y
v o l a t i l e
s u b s t a n c e a nd cannot
n o r m a l l y
be
c o n d e n s e d c o m p l e t e l y
by
c o o l i n g i n t h e o r d i n a r y
t y p e
o f
c o n d e n s e r , due
t o
t h e
p r e s e n c e o f
l a r g e
volumes
o f d i l u t i n g g a s e s . I t
i s n e c e s s a r y , t h e r e
f o r e , t o p r o v i d e a l i q u i d
a b s o r p t i o n
s y s t e m . o r
g a n i c o r
i n o r g a n i c ,
u s u a l l y employing
a
s o l u t i o n
of m a l e i c a c id in
water
a s an a bsor b i n g
medium
a s d e s c r i b e d
a n d
claimed
i n t h e patent
t o
Jaeger
a n d
J e w e t t ,
N o . 2 , 0 9 8 , 0 4 7 d a t e d
November
,
1 9 3 7 .
I n
t h e p a s t t h e m a l e i c
a n h y d r i d e
p r e s e n t i n
t h e
3 0 c o n v e r t e r g a s e s ,
p a r t i c u l a r l y
in the c a s e o f
the'
vapor
phase o x i d a t i o n
o f naphthalene
t o form
p h t h a l i c
anhydride a s a primary p r o d u c t , y h a s
been
o n l y i n c o m p l e t e l y r e c o v e r e d b e c a u s e
o f
t h e
f a c t that a c e r t a i n proportion o f
the maleic
a n
3 5 h y d r i d e c o n d e n s e s with t h e
p h t h a l i c
anhydride
b e f o r e
r e a c h i n g t h e
l i q u i d a b s o r p t i o n
s y s t e m . I n
the
c a s e o f p l a n t s
p a r t i c u l a r l y
d e s i g n e d
f o r
pro
duction o f phthalic anhydride,
t h i s
l o s s o f the
maleic anhydride present
m a y
a m ou n t
t o
a s
40
much s
50 .
Sin c e
m a l e i c a c i d
and
a l e i c a n -
h y d r i d e d e m a n d
a
h i g h e r p r i c e than
d o e s
p h t h a l
' i c a n h y d r i d e
and
t h e d e m a n d f o r
m a l e i c anhy
d r i e d
and
a c i d
i s
c o n s t a n t l y
i n c r e a s i n g , t h i s l o s s
i s
a
s e r i o u s economic f a c t o r a n d i t i s t h e
o b j e c t
4 5
o i
t h e
p r e s e n t
i n v e n t i o n t o r e d u c e t h i s
l o s s .
A c c o r d i n g
t o
t h e
p r e s e n t
i n v e n t i o n ,
c o n v e r t e r
gases f r o m the v a p o r
p h ase
c a t a l y t i c oxidation o f . ,
or ga n i c
compounds,
p a r t i c u l a r l y convertergases
which c o n t a i n
' m a l e i c anhydride
i n a d d i t i o n
t o
50 other c o m p ounds such as
p h t h a l i c
anhydride, are
. t h e gases
because
a n e ? e c t i v e s c r u b b i n g s y s t e m ,
( C l . 2 6 0 - 5 3 7 )
p a s s e d t h r o u g h a c o n d e n s i n g s y s t e m f o l l o w e d b y
a l i q u i d
s c r u b b i n g s y s t e m , b u t i n s t e a d
o f
c o o l i n g
the condensers e x t e r n a l l y
t o
as low a t e m p e r a
t u r e a s p o s s i b l e , they a r e maintained a t a ,t e m
p e r a t u r e
s u ? i c i e n t l y
high s o
t h a t m a l e i c anhy- 5
d r i d e remains v o l a t i l e .
In t h i s m a n n e r ,
maleic
anhydride i s
p r e v e n t e d
from c o n d e n s i n g
i n
s o l i d
f o r m a n d
s
recovered m o r e o r
l e s s
completely by
t h e l i q u i d s c r u b b i n g s y s t e m . W h i l e any
d e s i r e d
m e t h o d
o f m a i n t a i n i n g t h e t e m p e r a t u r e
i n
t h e 1 0
c o n d e n s e r s above t h e
c o n d e n s i n g
p o i n t
o f
m a l e i c
anhydride
can
be
u s e d , , I
have
found
t h a t
a t
l e a s t
f o r t h e c o o l e r
p o r t i o n s
o f t h e
c o n d e n s e r , i t i s
p r e f e r a b l e
t o
i n j e c t
hot i r . which t i l l
f u r t h e r
d i
l u t e s
the gas
stream
a n d e r m i t s
maintaining
t h e
maleic anhydride i n the vapor s t a t e
a t
tempera- 1 5
t u r e s which
are l o w e r t h a n those
n e c e s s a r y
i f n o
d i l u t i o n had
t a k e n
p l a c e . The
c u r v e s
o f v o l a t i l i t y
o f m a l e i c anhydride
a n d p h t h a l i c
anhydride
a r e
such that a b e t t e r
s e p a r a t i o n
i s
obtained a n d hot
a i r
i s
a cheaper
a n d , i r o m a n o p e r a t i n g s t a n d -
2 0
p o i n t ,
s i m p l e r method
o f
o b t a i n i n g t h e d e s i r e d r e
s u l t s .
T h e
d i l u t i o n o f .
the g a s e s
does
ot
m a t e r i a l
l y - h i n d e r t h e c o m p l e t e n e s s w i t h which t h e l i q u i d
s c r u b b i n g system removes
m a l e i c
anhydride
from 2 5
s u c h a s - f o r
example
t h e s t a n d a r d s y s t e m d e
s c r i b e d i n t h e
J a e g e r
and
J e w e t t
p a t e n t a b o v e
r e f e r r e d t o ,
w i l l
r e m o v e v e r y e ? i c i e n t l y t h e m a l e i c
a n h y d r i d e
f r o m l a r g e
v o l u m e s o f d i l u t i n g g a s e s .
The
b e s t p o i n t a t which
t h e
hot i r s h o u l d be
i n j e c t e d g w i l l
i n g e n e r a l
v a r y w i t h
t h e n a t u r e o f
t h e c o n v e r t e r
g a s e s a nd a l s o w i t h t h e p h y s i c a l
d e s i g n o f t h e
c o n d e n s i n g
s y s t e m ,
I n
c a s e s where
t h e c o n v e r t e r g a s e s
a r e o b t a i n e d
from t h e c a t a
l y t i c o x i d a t i o n o f v a p o r s , t h e ? r s t
s e c t i o n s o f
t h e
condenser a r e
a t
a s u ? l c i e n t l y
e l e v a t e d
t e m p e r a
t u r e
s o t h a t
i t i s
not n e c e s s a r y .
t o i n j e c t
hot a i r
i n t o
t h e m ,
. t h e i n j e c t i o n
t h e r e f o r e t a k e s v p l a c e
6 9 0
f u r t h e r
back
i n the s e r i e s o f c o n d e n s e r s . The 4 0 9
temperature
t , which
t h e . a i r
i s
i n j e c t e d s h o u l d
be mainta ined below
the
p o i n t a t which i t
w i l l
r a i s e
the
temperature
0 1 '
t h e g a s e s t o o
high
t o
p e r m i t e ? e c t i v e c o n d e n s a t i o n
o f
t h e p h t h a l i c
an
hydride
,
' I
,
Whil e
the
use o f
the
p r e s e n t invention i n
c o n
j u n c t i o n w i t h . c o n v e r t e r
g a s e s
fro m
t h e
c a t a l y t i c
o x i d a t i o n
o f naphthalene r e s u l t s
i n
a small l o s s
i n
p h t h a l i c a n h y d r i d e , i t i s a n advantage o f
t h e
i n v e n t i o n t h a t t h i s
l o s s
i s k e p t
l o w
a n d i s n o r - 5 o
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8/11/2019 Separation of Phthalic Anhydride
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10
1 5
m a l l y a b o v e t h e
p o i n t
i n t h e c o n d e n s e r where h e
g r a d e
o f p h t h a l i c
a n h y d r i d e
p r o d u c e d i s r e l a
t i v e l y l o w .
Of
o u r s e ,
s m a l l l o s s e s
o f
p h t h a l i c a n
h y d r i d e
a r e
n o t s e r i o u s e c o n o m i c a l l y b e c a u s e o f
t h e l o w e r p r i c e which p h t h a l i c
a n h y d r i d e
c o m
mands
and
n
a d d i t i o n ,
t h e p h t h a l i c
a n h y d r i d e
i s
not r e a l l y l o s t a s i t i s d i s s o l v e d i n the aqueous
o
l u t i o n i n t h e
a b s o r b i n g p o r t i o n o f t h e
s y s t e m a n d
i s
r e m o v e d
i n the
p r o c e s s . o f puri?cation o f
the
m a l e i c
a c i d l i q u o r p r o d u c e d . I t
i s t r u e
t h a t t h e
p h t h a l i c
a c i d i s o b t a i n e d fro m such
p r o c e s s e s i n
the fo r m o f
the
a c i d
a n d
sometimes i n
a
fo r m
which s n o t v e r y p u r e , but t
i s
not e n t i r e l y
l o s t
a n d c a n be used
f o r
many
u r p o s e s ,
such as f o r
ex ample.
the
production o f e s t e r s . ~ I t i s
a n ad-
v a n t a g e o f
the 'presentinvention that
the g r e a t - '
l y i m p r o v e d r e c o v e r y o f m a l e i c a c i d i s
o b t a i n e d
_ l with but l i t t l e
l o s s
o f
phthalic anhydrid e.
' 2 0
80
The i n v e n t i o n
w i l l
be d e s c r i b e d i n
g r e a t e r
de
t a i l
i n
c o n j u n c t i o n
w i t h
a s p e c i ? c
example
which
d e a l s
with
a
c o n v e r t e r gas
f r o m a
p a r t i c u l a r type
o f p h t h a l i c a n h y d r i d e p l a n t . I t s h o u l d be
under
s t o o d ,
o f
c o u r s e ,
t h a t
t h i s i s merely a n l l u s t r a
t i o n and t h a t
t h e
t e m p e r a t u r e and volume o f t h e
g a s employed w i l l n e c e s s a r i l y v a r y w i t h c o n v e r t e r
g a s e s
fro m d i f f e r e n t o x i d a t i o n s . A c c o r d i n g l y , t h e
i n v e n t i o n
i s
n o t c o m p l e t e l y l i m i t e d t o t h e
s p e c i ? c
details
set
f o r t h
i n
the example.
_ I
Ezamlile
, I n
t h e
p a r t i c u l a r p l a n t
w i t h w h i c h
t h i s e x
a m p le i s . c o n c e r n e d , about 4 , 0 0 0 l b s .
o f
p h t h a l i c
a n h y d r i d e
a r e p r o d u c e d
daily
and p p r o x i m a t e l y
a s
4 , 0 7 0 l b s . o f naphthalene a r e consumed. 3 4 6 0 l b s .
o f the
naphthalene
a r e
converted
i n t o p h t h a l i c
a n h y d r i d e
a n d
t h e
b a l a n c e .
o r
6 1 0
l b s . ,
i s
con
v e r t e d
t o
o t h e r p r o d u c t s ,
t h e
major o n e b e i n g
maleic anhydride. ,
Th e
c o n v e r t e r g a s e s a r e passed
through a con
d e n s i n g
system
w h e r e ' p a r t i a l o r c o m p l e t e
con
d e n s a t i o n o f t h e p h t h a l i c a n h y d r i d e t a k e s p l a c e
a l o n g
w i t h
some
o f
t h e
m a l e i c
a n h y d r i d e , depend
i n g
upon the
r a t e o f t h e g a s c o o l in g a nd
the c o n
denser wall
temperatures.
6 6 The
c o n d e n s e r s y s t e m
o f
t h i s
p a r t i c u l a r p l a n t
i s
composed
o f
a s e r i e s o f t h r e e round c o n d e n s e r s
with r o t a r y
s c r a p e r s
a n d a fourth box type
c o n
d e n s e r
which i s
merely
eum
etal box
w i t h .
b e l l i e s a n d a n
opening
i n t o a fume
t o w e r .
Th e
c o n d e n s e r s ha v e a
r e l a t i v e l y l a r g e s u r f a c e
area
t o
p r e v e n t
l o s s
o f
p h t h a l i c
a n h y d r i d e through h e
fume t o w e r
e s p e c i a l l y
d u r i n g hot sum m e r
weath
e r .
Some
f
the
maleic
a n h y d r i d e passes t h r oug h
t h e
c o n d e n s e r s
and
t
i s r e c o v e r e d from
t h e
fume
t o w e r
g a s e s
b y t h e
p r o c e s s
o f
t h e
J a e g e r
a n d
Jewett
p a t e n t
m e n t i o n e d
heretofore.
D u r i n g t h e
winter m o n t h s the w a l l tempe ratures of the c o n
d e n s e r s ' d r o p
t o
a
c o n s i d e r a b l e e x t e n t
. w h i c h
c a u s e s
a
r e a t e r c o n d e n s a t i o n o f p h t h a l i c - a n h y
d r i d e i n
t h e
i i r s t
condenser a n d
a l s o
i n c r e a s e s
_
the
a m o u n t
o f
m aleic
anhydride
that condenses
i n t o t h e c o n d e n s e r s , c o n t a m i n a t i n g t h e p h t h a l i c
anhydride a n d a l s o r e s u l t i n g in a decrease
o f
the
m a l e i c a c i d r e c o v e r e d i n
t h e
tune t o w e r . r .
2 , 2 2 0 , 0 4 4
The f o l l o w i n g
t a b l e
s h o w s t h e
d i s t r i b u t i o n
o f
maleic a c i d i n the conde nsers which
i s
not
r e
c o v e r a b l e
from h e
i u m ' e
t o w e r g a s e s
under m e a n
summ e r c o n d i t i o n s a n d m e a n w i n t e r c o n d i t i o n s .
M e a n M e a n
m m ? , Z i a ? i i
m m n s l o i m s c i d
m a l e i c
8 6 1 1 1
First c o n d e n s e r
. . . .
.;
. . . . . . . . . . . . .
0 .
4 0 . 7
Second condenser. .
0 .
8
3 . 0
Third
o n d e n s e r . . . . . . . . . .
4 . 0
l 2 .
0
Box condenser . . . . . . . . . . .
.
... 1 0 . 0
3 5 . 0
T o t a l n o t
r e c o v e r a b l e i n t h
iume
tower
...... ..... .. -.--.-
16.2
I 6 0 . 7
An x a m i n a t i o n
o f
t h e - t a b l e shows t h a t t h e r e
i s
a o s s
o f o n l y
15.2
o f m a l e i c
a c i d
by
condensa
t i o n which i n d i c a t e s a r e c o v e r y 0 1 84.8 under
a ve r a ge summer
c o n d i t i o n s ,
whereas there i s a
l o s s
o f 50.7
a n d o n l y a r e c o v e r y o f
49.3
under
w i n t e r c o n d i t i o n s .
Th e
a b l e
a l s o
shows
that t h e
c o n d e n s a t i o n
o f
m a l e i c a c i d i n
t h e f i r s t c o n d e n s e r
v a r i e s ve ry l i t t l e between su m m e r
a n d winter
c o n d i t i o n s but i n c r e a s e s r a p i d l y
i n
t h e o t h e r con
d e n s e r s
under
w i n t e r
c o n d i t i o n s .
1 0
1 5 '
20
. 2 5
when pproximately 620 cubic
f e e t
per
m i nut e
o f hot a i r
a t
t h e temperature o f
1 3 0 - 1 ' l 0
C .
a r e
i n t r o d u c e d
i n t o
the
i n l e t o f
t h e
second
condenser
a n d
c o r r e s p o n d i n g l y
s m a l l e r
amounts
i n t o t h e
i n l e t
o f
t h e t h i r d
condenser
a n d the b o x c o n
d e n s e r , c o n d i t i o n s simulating those o f sum m e r
are obtained a n d the maleic
anhydride
vapors a r e
c a r r i e d forward i n t o
t h e fume
tower
where
t h e y
a r e r e a d i l y r e c o v e r e d i n q u a n t i t i e s r e p r e s e n t i n g
85-90 o f t h e t o t a l
q u a n t i t y p r o d u c e d by t h e
process.
W h a t
I
claim s :
1 . A m e t h o d
o f
i n c r e a s i n g the
r e c o v e r y
o f
m a l e i c a c i d f r o m ' c o n v e r t e r g a s e s from t h e c a t a
l y t i c vapor phase o x i d a t i o n o f o r g a n i c c o m
p o u n d s w h i c h
c o n t a i n m a l e i c
a n h y d r i d e ,
w h i c h
c o m p r i s e s p a s s i n g
t h e
g a s e s through a
s e r i e s
o f
c o n d e n s e r s
a t
p r o g r e s s i v e l y d e c r e a s i n g t e m p e r a
t u r e s , f o l l o w e d by a n a b s o r b i n g s y s t e m i n which
m a l e i c a c i d i s
s c r u b b e d
o u t o f t h e g a s e s by
an
a q u e o u s
s o l u t i o n , i n j e c t i n g
h o t
permanent
g a s e s
s u b s t a n t i a l l y i n e r t t o m a l e i c a n h y d r i d e
a t
t h e
t e m p e r a t u r e
o f
t h e c o n d e n s e r s i n t o t h e
con
d e n s e r s t o
maintain t h e t e m p e r a t u r e
i n
a l l o f
t h e
c o n d e n s e r s
a t a
p o i n t
above t h a t a t which
s u b s t a n t i a l
q u a n t i t i e s
o f
m a l e i c
a n h y d r i d e
a r e
condensed under t h e
p a r t i a l
p r e s s u r e o f m a l e i c
anhydride
e x i s t i n g i n
t h e
g a s i n q u e s t i o n , where
by t h e m a l e i c
a n h y d r i d e whichwould
o t h e r w i s e
c o n d e n s e i s c a r r i e d forward i n
t h e
v a p o r p h a s e
i n t o t h e l i q u i d a b s o r b i n g s y s t e m and
t h e r e
d i s - i
s ol v e d
a s
m a l e i c acid.
2 . A
r o c e s s a c c o r d i n g t o c l a i m 1
i n which
t h e
v a p o r
phase
o x i d a t i o n
i s a c a t a l y t i c v a p o r p h a s e
o x i d a t i o n o f n a p h t h a l e n e t o p h t h e l i c a n h y d r i d e .
3 .
A r o c e s s a c c o r d i n g t o claim i n
which
t h e
aqueous
s o l u t i o n
i n t h e a b s o r b i n s system
i s
a n
a q u e o u s
solution oi
m a l e i c
acid.
1
- ALPHONS
.
JAEGER
30
3 5
a