EFFECT OF NH 3 and SO 2 ON n-BUTANE OXIDATION. V.A. Zazhigalov, V.M. ... modifies its acid--base properties, which changes its activity and selectivity.
React. Kinet. Catal. Lett., Vol. 38, No. 1, 147-152 (1989)
EFFECT
V.A. Yu.N.
OF NH 3 a n d
Zazhigalov, Merkureva,
Institute
SO 2 ON n - B U T A N E
V.M. A.I.
Belousov,
N.D.
Pyatnitskaya
of P h y s i c a l
OXIDATION
Konovalova,
a n d G.A.
Chemistry,
Kiev,
Komashko
252028,
USSR
Received April 19, 1988 Accepted May 26, 1988
It h a s b e e n e s t a b l i s h e d the
surface
t h a t NH 3 a n d SO 2 a d s o r p t i o n
of V - P - O c a t a l y s t s
at r e a c t i o n
modifies
its acid--base p r o p e r t i e s ,
activity
and
HOKa3aHO,
qTO
a~c0pSuHs HpH
NH 3 H SO 2 Ha n O B e D X H O C T H
TeMnepaTypax
H e H H m ero a K T H B H O C T H H - C 4 H ] 0 , qTO
SBH~eTCS
markedly
[1,2]
affect both
pe3ynbTaTOM
f r o m the
acidic
surface.
its
t h a t the
oxidation
sites The
of v a n a d i u m - p h o s p h o r u s
favors
literature oxide
V-P-O
HpHBO~HT
K H3Me-
B peaKHHH
OKHCne-
MO~H~HHHpOBaHH~
KOHTaKTa.
surface
the a c t i v i t y
l y s t s for the p a r t i a l of s t r o n g l y
peHKHHH
H ceneKTHBHOCTH
KHC~OTHO-OCHOBHbIX CBOHCTB
It is k n o w n
changes
selectivity.
KaTanH3aTopa
HHS
which
on
temperatures
and
acid-base
selectivity
of h y d r o c a r b o n s . the d e s o r p t i o n reports
(V-P-O)
properties
[3,4]
catalysts
of the c a t a The p r e s e n c e
of a c i d p r o d u c t s on the e f f e c t on the o x i d a t i o n
of C 4 - h y d r o c a r b o n s . We h a v e m a d e an a t t e m p t of the V - P - O temperature
to e l u c i d a t e
whether
c a t a l y s t by a c i d a n d b a s e m o l e c u l e s would
change
the V - P - O
surface
and
the t r e a t m e n t at a g i v e n
its c a t a l y t i c
properties. EXPERIMENTAL The p r o m o t e d Butane
(1.5 v o l . %
V-P-O catalyst in air)
was p r e p a r e d
was o x i d i z e d
like
in Ref.
[5].
in a T e m k i n - K u l k o v a q u a r t z
Akaddmiai Kiadd, Budapest
ZAZHIGALOV et al.: n-BUTANE OXIDATION
flow reactor. catalyst was
Upon achieving f o u n d to be a
its s t e a d y - s t a t e
activity,
the
(VO)2P207 p h a s e w i t h a s u r f a c e a r e a
of S = 21 m2/g. E f f e c t of NH 3 and SO 2 on the o x i d a t i o n s t u d i e d by two m e t h o d s : c o n t a c t at r e a c t i o n S02;
temperatures
(2) c o n t i n u o u s
the r e a c t i o n
(I) r a p i d
admittance
K, b u t a n e
some c a s e s up to 60 %). The not a f f e c t
the q u a l i t a t i v e
is seen f r o m T a b l e
by v a r i o u s
of n - b u t a n e
amounts
introduction composition
of NH 3 or
together
temperatures. conversion
was
of a s t e a d y - s t a t e
of t h e s e g a s e s
m i x t u r e at r e a c t i o n
c a r r i e d out at 6 5 3 - 6 8 3
treatment
with
The r e a c t i o n was
was
15-40
%
(in
of NH 3 a n d SO 2 d o e s
of the p r o d u c t s ,
which
I. Table Product
I
composition
C o n c e n t r a t i o n
(vol.%)
Mixture C4H10(init.)
C4H10(fin.)
C4H203
CO
CO 2
C4HI0+O2
I .50
0.87
0.38
0.32
0.60
C4HI0+O2+NH3
I .50
0.90
0
0.38
I .98
RESULTS AND DISCUSSION The e f f e c t of t r e a t m e n t face by a m m o n i a in Fig.
the rate of b u t a n e
In this c a s e
oxidation,
and
oxidation
a m o u n t of NH 3 a d m i t t e d effect.
With
oxidation.
148
90-1!0
to t h e i r
formation
for the p r o d u c t s higher.
An
surface
efficiency
m i n the c a t a l y s t
initial
values.
sur-
r a t e of decrease.
of c o m p l e t e
increase
the r e a c t i o n
t r e a t e d by NH3,
in the c a t a l y s t
After
are r e s t o r e d
the
significantly
to the c a t a l y s t increasing
face of the V - P - O c a t a l y s t rise
become
catalyst
is i l l u s t r a t e d
of NH 3 d o e s not c h a n g e
whereas
its s e l e c t i v i t y
the f o r m a t i o n r a t e s
and destructive
gradual
steady-state
characteristics
I. It is seen t h a t the a c t i o n
maleic anhydride
observed
of the
on the r e a c t i o n
in the
enhances
the
t i m e on the
one can o b s e r v e
with respect activity
and
sura
to p a r t i a l selectivity
ZAZHIGALOV et al. : n-BUTANE OXIDATION
Sma'(% )
3
"402T~/
2,
3
3
A t-
4 E -6 3
E
9- n .
,,.,.
o'f
X
NH3
(a)
0
Fig.
!I
NH3 (b) ~
40
80
d
120 0 t (rnin)
I. Effect of rapid c a t a l y s t
-
-
'
40
80
120
t r e a t m e n t by NH 3
(a -- 1.02x10 -6 and b -- 6.04xi0 -6 m o l / m 2) on the rates of butane o x i d a t i o n anhydride maleic
formation
anhydride
(I), maleic
(2), s e l e c t i v i t y
toward
(3), acetic a c i d f o r m a t i o n
(4)
This effect can be i n t e r p r e t e d using the data on the p r e s ence of strongly a c i d i c
sites on the surface
strongly a d s o r b a m m o n i a
[5]. The d e a c t i v a t i o n
ammonia d e c r e a s e s acid p r o d u c t
the p r o b a b i l i t y
(maleic anhydride)
further o x i d a t i o n served towards
formation
rate of maleic
dependent
for the d e s o r p t i o n
Gradual
surface.
anhydride
of the above
desorption
These r e s u l t s
reaction mixture
are c o n f i r m e d admittance
to the r e a c t i o n
that the rate of partial anhydride
and the s e l e c t i v i t y conversion
or its removal
restores
the
is in-
from
initial
by the data o b t a i n e d of ammonia zone.
oxidation
together
char-
mixture
in e x p e r i with the
It is seen from Fig.
and the s e l e c t i v i t y
drop to zero and r e m a i n u n c h a n g e d
whole p e r i o d of a d m i t t i n g B by m i x t u r e
the ob-
of the process.
ments with c o n t i n u o u s
maleic
of the
the degree of its
sites and hence r e m a i n s
of a m m o n i a
the surface by the r e a c t i o n p r o d u c t s acteristics
that
sites by
As a result,
The rate of h y d r o c a r b o n
of the p r e s e n c e
unchanged.
of these
and increases
on the c a t a l y s t
it decrease.
of c a t a l y s t s
during
B. The r e p l a c e m e n t
A leads to a g r a d u a l l y
increasing
2
towards the
of m i x t u r e
efficiency
of 149
ZAZHIGALOV et al. : n-BUTANE OXIDATION
Sma(% )
4o t
E3
2
x 2
J
I
-"ll
/-
tl
I/
I
I i I
0
Fig.
2. C h a n g e s
40
80 S60 0 t (rain)
i I i I
L,O
in the r a t e of m a l e i c
80
anhydride
formation
(2) a n d selectivity t o w a r d m a l e i c
anhydride
after replacing
A
C4HI 0
in
air)
reaction
mixture
by m i x t u r e
B
(1.5 v o l . %
+ 0.32 V o l . % of NH 3 in air);
(3)
(1.5 v o l . % C4HI0
I - oxidation
of
+ rate
of b u t a n e
the c a t a l y s t
and the r e s t o r a t i o n
of
The e f f e c t of SO 2 on b u t a n e Figs
3 and
4. T r e a t m e n t
e i t h e r t h e r a t e or the This
of the c a t a l y s t selectivity
can be due to e i t h e r
molecules
its i n i t i a l
oxidation
surface
is c o n f i r m e d
by the d a t a g i v e n
that
the a d d i t i o n
of SO 2 to the r e a c t i o n
in Fig.
and maleic
The 4.
latter assump-
It can be s e e n
mixture
decreases
anhydride
selectivity
remains practically
changed.
of r e a c t i o n
mixture
The r e p l a c e m e n t
oxidation
by the r e s t o r a t i o n
and maleic
This phenomenon mechanism
150
anhydride can be
for the a c t i v a t i o n
C by mixture
of the r a t e s
formation
interpreted of b u t a n e
the
formation.
In this c a s e the p r o c e s s
is a c c o m p a n i e d
3).
of a c i d
[5] or the h i g h r a t e
of t h e s e m o l e c u l e s .
oxidation
(Fig.
of the a d s o r p t i o n
tion
r a t e of b o t h b u t a n e
in
by SO 2 d o e s not a f f e c t
of this r e a c t i o n
the a b s e n c e
on the V - P - O c a t a l y s t
of a d s o r p t i o n - d e s o r p t i o n
characteristics.
is i l l u s t r a t e d
unA
for b o t h b u t a n e
to t h e i r in t e r m s
initial
values.
of the p r o p o s e d
[6] a n d some o t h e r p a r -
ZAZHIGALOV
et al. : n-BUTANE
OXIDATION
Sm.a.(%)
r-
~4
1
E ~3
--o.--o-~
40 2
X
1
~
2
--o--o-o--o
20 I
0
40
80
0
40
t (min) Fig.
3. E f f e c t
of c a t a l y s t
treatment
by SO 2
(a - 6.5xi0 -7
and B - 4.6xi0 -6 m o l / m 2) on the r a t e s oxidation
(I) and m a l e i c
selectivity
towards
anhydride
maleic
of b u t a n e
formation
anhydride
(2);
(3)
Sin.a(%)
--4
~
1
1
2 .
x
1 I
I
I
0
I
I
I
I
I
'If[
I
I
80 360
40
I
,
0
I
1
1
i
T
I
I
I
80
40
't(min)
Fig.
4. C h a n g e s
in the r a t e s
maleic
anhydride
action
mixture
of b u t a n e
formation
A by m i x t u r e
+ 0.27
vol.%
maleic
anhydride
of SO 2 in air);
oxidation
(2) a f t e r
(I) a n d
replacing
C: (I .5 v o l . % selectivity
re-
of C4HI0
+
towards
(3) 151
ZAZHIGALOV et al. : n-BUTANE OXIDATION
affin h y d r o c a r b o n s is o b s e r v e d o x y g e n atom,
i.e.
tion of these reduces
[7] involving
p r o t o n abstraction.
in the p r e s e n c e of excesS e l e c t r o n in the p r e s e n c e
of b a s i c
sites during the a d s o r p t i o n
the p r o b a b i l i t y
sites
[7,8]. Deactiva-
of the acid
for the h y d r o c a r b o n
not affect the ratio of the rates
The latter
density on the
(SO 2)
activation
for p a r t i a l
and does
and c o m p l e t e
oxida-
tion. Thus the results or base m o l e c u l e s
indicate
that the i n t r o d u c t i o n
into the r e a c t i o n m i x t u r e
surface p r o p e r t i e s
of acid
chang%s b o t h the
of the V - P - O c a t a l y s t and the p a r a m e t e r s
of
b u t a n e oxidation. REFERENCES I. G.I. Golodets: Molecular
2. M. Ai: Proc. Tokyo
S. Suzuki:
Reactions Involving 1983.
on Catalysis,
Preprint
B 28,
3074
N.D. Konovalova,
Surface,
p. 218.
10,
Catalysis
Institute
G.A. Komashko,
I.V. B a c h e r i k o v a , All-Union
Sokolovskii:
cesses,
Soc. Jpn, 47,
Belousov:
Conf.
2, p. 286. Moskva
p. 41.
8. H. Vinek,
Chem.
55
(1974). Yu.P.
(1987).
and P r o g r e s s
in
of Catalysis,
1984.
Pyatnitskaya,
G. Ladwig:
V.A.
Zazhigalov,
H. Seeboth,
B. Lucke,
M e c h a n i s m of C a t a l y t i c
V.M. H. Wolf, Reaction,
1978.
Mechanism
Institute
H. Noller,
Faraday Trans.,
152
Congr.
R. Krupa:
V.M.
Engineering,
Belousov,
Vol.
Bull.
J. Stoch,
Novosibirsk
7. V.D.
Amsterdam
V.M. Belousov,
Zazhigalov,
Chemical
6. A.I.
7th Intern.
Zazhigalov,
Zaitsev, 5. V.A.
Catalytic
Elsevier,
1980.
3. M. Ai, 4. V.A.
Heterogeneous
Oxygen.
and Kinetics
of Catalysis,
M. Ebel,
I, 73, 734
Novosibirsk
K. Schwarz:
(1977).
of C a t a l y t i c
J. Chem.
Pro-
1977. Soc.,
