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Ammoxidation of alkylpyridines on vanadium oxides with and without oxygen
231
Applied Catalysis, 10 (1984) 231-249 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands
AMMOXIDATION
ALFONS
BAIKER
Swiss and
OF ALKYLPYRIDINES
and
Federal
Institute
Engineering
(Received
PETER
AND
WITHOUT
OXYGEN
ZOLLINGER of Technology
Chemistry,
6 January
OXIDES WITH
ON VANADIUM
1984,
CH-8092
accepted
(ETH).
Zurich.
Department
of
Industrial
Switzerland.
16 March
1984)
ABSTRACT The ammoxidation of 3-alkylpyridines on unsupported, unpromoted vanadium oxides has been investigated in the presence and in the absence of molecular oxygen. The latter reaction, resulting in the reduction of the vanadium oxide. was termed oxidative ammonolysis. Reactyons were performed under nearly isothermal conditions in a microscale fluidized bed reactor in the temoerature ranae from 250' to 45O'C. Vanadium oxides were characterized by X-ray analysis, TPR. BET and titrimetric measurements. Ammoxidation of 3-picoline on V205.gave a maximum yield of 60% 3cyanopyridine at 370°C, corresponding to 90% conversion. VA09 exhibited a similar ._ selectivity as V2O5. VO2 was active, -but nonselective, and'converted rapidly to under ammoxidation conditions. Of the multiple phase oxides, V205/V4Og and '6'1 V4Og?VO2 showed a selectivity comparable to the single phase oxides, V2O5 and V4Og; however, their properties changed under ammoxidation conditions. 3-ethylpyridine was ammoxidized with comparable activity and selectivity as 3-picoline. In contrast, ammoxidation of 2-methyl-5-ethylpyridine gave a maximum yield of only 25% 3-cyanopyridine. due to enhanced destruction of the pyridine ring.
INTRODUCTION Ammoxidation pyridine in the tinic
has
gained
synthesis acid
portant
are
part
tained
hydration
of more acid
line
but
[8],
Research [9] and
than
90%
can
are
supported
Probably
0166-9834/84/$03.00
the
most
because
of the
nicotinamide
[4-61
and for
hydrolysis both
also
or,
reports pentoxides
[l].
The [2.3]
and
by direct to those
[lo-211. have
of the
has
can
been oxides
are
intrinsic
0 1984 Elsevier Science Publishers B.V.
into
very
im-
by
nicotinic
acid with
respectively.
oxidation
studies,
nico-
an ob-
be performed
acid,
prompted
employed
plays
be transformed
ammoxidation
In most
step and
3-cyanopyridine
vapor-phase
of the
a decisive
which
can
nicotinic
to 3-cyano-
nicotinamide
by hydrolysis,
of 3-cyanopyridine
vanadium
studies
Both
B complex
up to 85%
of alkylpyridines
unpromoted
detailed
vitamin
nicotinamide
low compared
vanadium
acid.
and mammals yields
of 3-picoline
it constitutes
nicotinic
with
scientific
on unsupported,
of
of men
step
ammoxidation
of
in particular,
interest and
be synthesized
yields
on the
a series
and
studies
metabolism
into
and,
to be parts
ammoxidation
hydration
Nicotinic
moted
considered
Catalytic
yields
considerable
of nicotinamide
in the
by the
catalytic [7].
of 3-alkylpyridines
of 3-pico-
route.
numerous
patents
differently
as catalysts,
pro-
whereas
scarce.
activity
and
specificity
232 of vanadium
oxides
carried
by Andersson
out
nadium
oxides,
active
and
both
phases, menon the
selective
they
the
This
latter
work.
Oxygen
oxidative Special
haviour
of the
of the
phase
when
of the
found
oxides
so far,
that and
to V204
phase
boundary
V6013
that
was
those
the
the
V60,3
reaction.
of both oxides.
surfaces
are
of different
during
consisting
single
of active
reported
investigations
they
reduced
is carried the
type
required
for the
resulting
of
V205
The
was
Further-
and
V60,3
latter
which
vamost
pheno-
accompanied
will
was
devoted
the
presence
also
of molecular
be performed
be termed
oxidative
oxygen;
without
"oxidative
ammonolysis
molecul-
ammonolysis" reaction
is sup-
in its reduction.
work
vanadium
during
in the can
to
investigate
3-alkylpyridines
was
different
out
reaction
reaction
present
emphasis
properties
any
that
catalyst,
ammonolysis
oxides.
single
their
phases.
[22].
objective
V204.
catalyst,
than
ammoxidation
the
and
extent
creation
shown
present
catalyst
V6013
been
by the
The
the
it has
ar oxygen in the
the
In
of the
to some
of 3-picoline.
[Zl].
V6013
and
to the
of new
Generally however,
Lundin
V205.
selective
ascribed
formation
plied
that
more
ammoxidation
and
catalyst
to V205
found
was
was
the
including
oxidized
more,
for
the
ammoxidation
on unpromoted,
unsupported
to examining
oxides
course
and
of
to
the
activity
and
investigating
the
as well
as
vanadium
selectivity changes
be-
in the
reaction.
EXPERIMENTAL Catalyst Pure sent 4.6
vanadium
pentoxide
investigation. m2/g;
solid
as measured ticle
size. ning
For the
reement lues
/Iolo
intensities
with
g/cm3:
consisted
specific
were:
3.40 pore
of agglomerates
presented defined
of the
pentoxide
nonoriented
plates
in Figure
by Zihlkowski
X-ray
calculated
in the
action
were
(TPR),
titrimetric
relco
pentoxide
was
used
BET
surface apparent
g/cm3;
volume,
in the
0.258
pre-
area, density
cm3/g;
par-
lines
used, for
for
f was
of grains
as becomes
1 and and the
the
Janas
found
less
than
from
1 pm
the
scan-
determined
morphological
[23].
and
respective
[24]
I,o,
planes
to be 0.95
a monocrystal
of
evident
and
which with
Iolo
given
are
the
by the
in-
is in good
experimental
agva-
samples.
characterization
Changes
electron
vanadium
Switzerland
urn.
vanadium
for
AG,
by He-pycnometry,
1.81
f = 0.90
obtained
Catalyst
of the
not well-developed
micrograph
f = I,o,
measured
120-250
were
by Fluka
as measured
pentoxide
grains
electron
factor
dex.
range,
vanadium The
Properties
density
by Hg-pycnometry,
size
The
supplied
physical
and
characterized
microscopy.
(Philips)
methods, The
chemical
by X-ray nitrogen
X-ray
diffractometer
properties
diffraction, adsorption
diffraction using
CuKa
of the
vanadium
temperature measurements
measurements radiation.
The
were
oxide
programmed (BET)
and
performed
apparatus
used
during
re-
reduction scanning with for
a Nothe
233 TPR
measurements
has
obtained
under
hydrogen
in nitrogen
The
average
[26]
using
FIGURE and
the
been
oxidation
1
Scanning
number
rate
of the
permanganate
electron
ammonolysis
previously
conditions:
at a flow
potassium
oxidative
described
following
[25].
sample
The
weight,
of 75 cm3(NTP)/min; vanadium
and
micrograph
iron
was
TPR-profiles
shown
were
75 mg;
reducing
gas,
heating
rate,
lO'C/min.
determined
by titrimetric
6%
methods
sulfate.
of vanadium
pentoxide
used
in ammoxidation
experiments.
Reactants Air,
ammonia
mercially (98%.
available
supplier
pyridine The
Apparatus The
was
Lonza
impurity
and
2 cm
installed
nitrogen gas
cylinders.
3-ethylpyridine
AG),
of the
were
fed
The
(99.5%.
to the
3-picoline
were
(99.99%)
was
fed
liquid
Fluka
reactor
to the
reactants,
AG)
and
without
4-picoline
reactor
from
com-
3-picoline
2-methyl-5-ethyl-
further
purification.
(1.5%).
procedures
experiments and
and
compressed
Reilly),
(99%.
major
length
(99.99%)
were
inner
in a gas
performed
diameter.
in a microscale For
chromatograph
temperature oven.
fluidized control,
Temperatures
bed
this in the
reactor
Pyrex
of
glass
fluidized
18 cm reactor
bed were
234 monitored water
with
were
dosed
ed through actants ous
0.5
and
products,
products
and
stream
Experiments reaction
precision
shown
tions:
amount
monia,
0.86;
in this
were
air,
without
conditions,
the
reaction
molecular
the
air
was
and
under
reactor
following
oxygen)
replaced
oxidative
were
was
standard
condi-
0.26;
am-
ammonolysis
performed
fed
ammoxldatlon
in mmol/min:alkylpyridine, The
(1 Mel/l). desired
reactor
The
re-
nongase-
to the
the
pass-
of
ammonia
cm3/min)
nitrogen. the
the
and
The
the of
temperature,
air
5003)
heated.
solution (250
and
condensation
by passing
air
392 cm3(NTP)/min.
free
but with
tubing
V205in
rates
Precidor.
To avoid
absorbed
conducted
alkylpyridines
(Infors
an aqueous
water,
10 g; feed
10.14;
were
the
ammonia,
paper
of catalyst,
(ammoxidation
standard
reaching
The
reactor.
and outlet
containing
by heating
After
pumps
the
alkylpyridine
started
water,
infusion
inlet
bubblers
of alkylpyridlne,
experiments
thermocouples.
entering
reactor
unreacted through
were
NiCr/Ni
before
the
temperature.
mixture
ments
by high
an evaporator
effluent
the
mm diameter
under
experi-
the
same
by nitrogen.
Analysis The
unreacted
temperature a 5% SP-1000 dinitrlle carrier 250°C
on
was gas;
with
monoxide
employed
bon dioxide
carbon
ous
phases
total
CT
mass
n
carbon flow
the
identified
+
was barium
wac_ used
as
linearly
products,
carbon
dioxide
To determine
mixed
effluent
acid
with
carbonate gas was
was the
enough
to
carbon
car-
aqueous
measured measured
graviwith
was
every CT
performed
an
15 minutes
In the
for
integral
effluent
tarry
each
analysis
experiment. of the
during
the
stream
of the
To collect
condensed
experiments.
The
reactor
the
and gasenormalized
is given
by eq.
1):
z i
of product
total
The
a
with
Succinlc
raised
oxidation
with
equipped
2 m).
was
solution.
solution
analyzed
900)
(30 cm3/min) 100°C.
separately.
of the
Mod
length
total
product
precipitated
content
at
gaseous
are the molar flow rates and n p,in p-out atoms at the reactor inlet and outlet,
rate
in the
The
product
balance,
conducted
"p,in
where
and
balance
this
of carbon
"p,out
=
starting
analyzed
20 ml of the
4 mm. helium
standard:
ammoniacal
monoxide
(i.d.
were
Elmer,
tubes.
for
was
amount
were
in the
products
(Perkin
column
of 8'C/min.
chloride
carbon
necessary
nongaseous
temperature,
dioxide,
carbon
detector
A total data
The
the
as an internal column
absorbed
of barium
and
chromatograph
Supelcoport
rate
content,
metrically. Drager
the
a heating
and
gas
lOO/lZO
and
quantitatively
solution
alkylpyridine
programmable
i containing
by-products,
carbon
mass
all
balance.
Bi carbon products The yield
of the
alkylpyridine
respectively,
atoms. were
With
the
identified
of the
tarry
and:
containing
exception and
taken
products
ai
ni is the molar of
some
into
Xtar
was
un-
account calcu-
235 lated
from
the
is defined
total
in eq.
carbon
mass
balance
using
the
relation
Xtar=l-CT,
were
CT
(1).
Definitions Conversion products
(X)
x 100.
"i.out
Bi
"p,in
oi
xi =
The
selectivity
and
totally
is defined
The
yield
as the
, Xi,
fraction
of the
of a specific
alkylpyridine
product
converted
is defined
by eq.
into
(2):
1oo
(X)
is the
converted
ratio
of alkylpyridine
converted
to a specific
product
x 100.
RESULTS Ammoxidation The oxide and
of alkylpyridines
ammoxidation were
on
reactions
investigated.
For
the
plotted
as a function
the
three
highest
dine
the
selectivity
amounted
yield
tivity
to 60%
was 4):
at total only
the
not
ditions
ammoxidation
in the the
case
tion -1820
was
with
species,
reactions: for
we -495
of 60%.
yield
respectively. exhibited of 3-cyanopyri-
selectivity
comparable
at about
corresponding
and
carbon
yield
carbon
in the
In con-
vanadium
pentoxide
90 minutes,
(Figure
of 3-cyanopyridine
monoxide,
product
38O'C.
to a selec-
monoxide.
the
are
of 2-methyl-5-ethylpyridine
and
during of
[27]
2-cyano-5-ethyl
mixture.
no marked
Within
change
was
for
the
the
the
Z-methyl-5-ethylpyridine.
the
temperature
of 3-picoline. reaction.
reaction
and
calculated
and
to control
ammoxidation
kJ/mol
maximum
the maximum
found
about
4,
and
3-picoline
3-ethylpyridine;
dioxide
dioxide were
2.3,
3-ethylpyridine,
3-ethylpyridine
heats
data
and
of 3-ethylpyridine, products
and
pent-
dura-
observed
selectivity.
required
the
in the
literature
kJ/mol
of
be maintained
ked differences
maining
feed
(~2%)
and
of
ammoxidation
generally
activity
carbon
at 4OO'C.
to carbon
pyridine
experiments,
could
By using
and
were
the
on vanadium
reaction
of
activity
its maximum
3-picoline the
An
ammoxidation
reached
for
in Figures
ammoxidation (67%):
at 37O'C. the
reached
In addition
(~5%)~
of water was
selective
catalyst
For
for
with
conversion,
25%.
of the
in the
occured
by-products
reactions
weakly
was
pyridine
and
3-picoline.
of the major
temperature the
alkylpyridines
of
yields
to 3-cyanopyridine
observed
Major
pentoxide
different
reactions,
of 3-cyanopyridine
to the
only
tion
was
of 65%.
trast
reaction
ammoxldation
to 3-picoline the
of
three
ammoxidation
of Z-methyl-5-ethylpyridine,
Of these
vanadium
for
for
the
incremental
following
3-picoline.
Z-methyl-5-ethylpyridine.
This
where
behavlour
ammoxidation method
enthalpies -1107
in the nearly
kJ/mol
reactor.
of these
at 623
use This
isothermal
is due
of Benson
for
the
mar-
compounds.
[28]
K for
con-
to the
the
for
the
re-
ammoxida-
3-ethylpyridine.
and
236
I
I
I
.*.-
/ @CONVERSION .3-CYANOPYRIDINE./ aCARBON MONOXIDE oTAR vCARBON DIOXIDE
*
/
450
400
350
300
250
TEMPERATURE('0
FIGURE sion
2
Ammoxidation
and
yields
particle
size
ammonia,
0.86:
in the under and
these
those
This
the
for
before
and
water
reaction
after
surface of the
(392
vapor
same
the
Figure
maximum
yield with
diffraction,
measurements.
vanadium
pentoxide
of V205,
10 g;
3-plcollne,
that
use
the
of 73%
to an 80% 60%
in the
0.26;
changed
but
3-picoline, the water
results
with
(Figure
decreased
3-cyanopyrldine
selectivity
and
a 67%
vapor
obtained
water
of water
ex-
2)
the
obtained
to 3-cyanopy-
selectivity
to
feed.
experiments,
These
of
the
obtained
temperature
area
conditions, 5 presents
results
of only
water
ammoxidation
ammoxidation
yield
corresponds
amount
in mmol/min:
of conver--
cm3/min).
standard
of the
Dependence
conditions:
rates
on the
5) indicates The
to a maximum the
by X-ray BET
properties
ments.
the
feed
by nitrogen.
(Figure
without
compares
17.47
A comparison
water
experiments
and
under
substituted
pentoxide.
Standard
pm;
of water
to 3-cyanopyridine.
characterized methods
air,
influence
conditions.
3-cyanopyridine Both
120-250
10.14;
conducted
was
without
selectivity
ridine.
the
on vanadium
temperature.
of V205'
water,
were
feed
in the
on reaction
range
To examine periments
of 3-picoline
the
programmed methods during
vanadium reduction,
gave the
no
pentoxides
were
titrimetric
indication
ammoxidation
that
experi-
231
100
I
I
a-
.).
*CONVERSION s
/
80-
m 9 g
l
/ 60-
i
n 3-CYANOPYRIDINE ..'
vCARBON DIOXIDE \ z qCARBONMONOXID J 8 40- oTAR 5; i!zl / -0-o h Lo_o-+ s 20' f o/zvm q:v 0 rraalnfllcllm'lm*a* 350 300 250
.\
_
450
400
TEMPERATURE('C)
FIGURE on
3
reaction
Ammoxidation temperature.
of 3-ethylpyridine. Standard
Dependence
conditions,
see
of conversion
Figure
and
of yields
2.
*CONVERSION
v 2-CYANO-5-ETHYL-
250
300
350
400
450
TEMPERATURE('C)
FIGURE
4
Ammoxidation
yields
on
reaction
of 2-methyl-5-ethylpyridine.
temperature.
Standard
conditions,
Dependence see
Figure
of conversion 2.
and
of
238
100
I
I
. CONVERSION n 3-CYANOPYRIDINE ‘v CARBON DIOXIDE 0 CARBON MONOXIDE 0 TAR
80
I
Jet ./ m-m
\
n
400
350
300
250
TEMPERATURE
FIGURE
5
version
Ammoxidation and
yields
however,water
Oxidative The
on
vapor
reaction
replaced
ammonolysis
oxidative that
the
amount
of nitrogen
the
in the
vanadium
on
experiments
normally
and
water
temperature.
of alkylpyridines
air,
3-ethylpyridine,
without
in the
Standard
feed.
conditions
Dependence (see
of con-
Figure
2);
by nitrogen.
ammonolysis
except
pound,
of 3-picoline
(‘C >
used
feed.
for
The
vanadium
were the
oxidative
exhibited
under
ammoxidation,
was
ammonolysis
Z-methyl-5-ethylpyridine pentoxide
pentoxide
performed
were
standard replaced
reactions
investigated,
an instationary
of 3-picoline,
With
behaviour
conditions, by an equal
each
com-
in activity
and
selectivity. Figure
6 depicts
coline
at 355'C.
higher
temperatures
observed first
hours
the the
instationary
Two
with
two
appeared second
after
became
of the
behaviour
distinct
maxima
separate
maxima
about
maximum,
catalyst
course
instationary
[29].
to coincide
maximum
Following five
the
A similar
the
50 minutes activity
almost
oxidative of this
ammonolysis
reaction
in the
3-cyanopyridine
in the
3-picoline
and
the
decreased
completely
second
inactive.
of
3-p1-
occured
at
yield
were
conversion.
The
after
continuously
also
145 minutes. until
after
about
239
50 CONVERSION n 3-CYANOPYRIDINE v PYRIDINE l
\
I
0 60
0
120
180
240
300
360
TIME ON STREAM (MINUTES)
FIGURE and
Oxidative
6
yields
on time
particle
size
ammonia,
0.86;
the
of the
formation
complete
duction
of the
Figure
lost
the
Compared
towards
3-vinylpyridine.
the with more
nitrogen,
Standard
17. 47
by-products,
by-products. from
was
due
3-cyanopyridine similar
of
to the was
and
tar,
experiments, the
total
the
observed
the
of V205,
3-picoline,
the
(Figure
due
oxidative
the
10 g
0.26;
second
that
re-
conditions
6) the
of
used. 3-ethyl-
vanadium required.
to a significant ammonolysis
consumed
further
ammonolysis
consumption
enhanced
at different
of oxygen
ammonolysis
oxygen
mainly
with
temperature
performed amount
for
3-picoline
low,
amount
peaked
indicating
under
conditions,
conversion
cm3/min).
Increasing
higher
of
in mmol/min:
constant,
course
ammonolysis
rapidly,
Under
was
impossible
instationary the
all
to 411'C.
deactivation oxide
(392
yield.
Dependence
conditions:
rates
pyridine
With
355'
at 355'C.
urn; feed
3-cyanopyridine
range
vanadium
its activity
selectivity of
major
catalyst
7 depicts
120-250
10.14:
of these in the
before
pyridine.
for
of 3-picoline
of catalyst.
of V205,
water,
observed
temperatures
on stream
range
Production maximum
ammonolysis
oxide The
production
performed
with
240 Z-methyl-5-ethylpyridine the maximum
yield
of by-products
also
showed
an
of 3-cyanopyridine
such
as carbon
2-cyano-5-ethylpyridine
and
instationary
was
dioxide,
only
about
carbon
course
of the
5%. due
to the
monoxide,
pyridine.
reaction, large
but
production
3_ethylpyridine,
tar.
I
I
I
I
. CONVERSION n 3-CYANOPYRIDINE r3-VINYLPYRIDINE v CARBON DIOXIDE qCARBON MONOXIDE
0
I 60
0
TIME FIGURE sion
7
and
The
Oxidative yields
of water
shown
8. A similar
where
the
reaction
comparison
of the
significantly fed
to the
ne.
the
about To ges
on
more
in the
was
physical
the
latter
more
with
vapor
this
in the
6 and 8 reveals selective
80%;
in the
feed are
is observed (Figure
that
the
at the maximum with
yield water
Figure
and
6).
of 60%
the
in-
in Fi-
in the
case
However,
vanadium when
was
6.
repeating
plotted as
feed
to 3-cyanopyridine
whereas,
see
of 3-picoline
experiment
reaction
water
conditions,
of conver-
oxide no water
a was was
3-cyanopyridi-
maximum
yield
was
selectivity.
of the
chemical
from
Dependence
ammonolysis
the water
of the
case,
than
to 70%
source
and
out
and more
In the
corresponding
investigate
course
at 355'C.
Standard
oxidative
for
in Figures
active
reactor.
on the
6. Results
carried
results
(MINUTES)
of catalyst.
nitrogen
instationary
selectivity
30%.
stream
in Figure
was
ON STREAM
of 3-ethylpyridine
vapor
by substituting
experiment
gure
on time
influence
vestigated the
ammonolysis
240
180
120
observed
properties
instationary of the
vanadium
reaction
behaviour,
pentoxide
that
chan-
occured
241 during
reaction
duction.
characterized
were
by X-ray
and
methods,
titrimetric
BET
diffraction,
surface
I
area
temperature
I
I
programmed
re-
measurements.
I
*CONVERSION n 3-CYANOPYRIDINE
60
0
120
180
240
TIME ON STREAM (MINUTES) FIGURE
8
Oxidative
of conversion tions,
see
Table
and yields
Figure
1 contains
during
the
Figure
6, the
the
times
where
red.
The
vanadium
ning
repetitive
each
from
The
from
the
consisted
oxide
about
50 and
145
of
the
of
vanadium
that
different number
the
reaction
vanadium
and
oxide
was
as detected
of the
vanadium
changed
by an
increase
accompanied
5 to 29 m'/g.
The
highest
at the
yields
times
of
where
by
6. As
X-ray from
average
in
correspond yield
obtained
at the
B and
times
indicated
oxide
were
yield
OCCU-
by run-
desired
D. which
time.
were
in 3-cyanopyridine,
diffraction. 5+to
in the
3-cyanopyridine the
at selected
stopped
samples
condi-
of nitrogen.
vanadium
times
Dependence
Standard
3-cyanopyridine
to maximum
phases
was
i.e.,
measured
of the
feed.
amount
in Figure
to these
corresponding
change
minutes:
at 355'C.
oxide
in conversion
in the
by equal
shown
corresponding the
water
of catalyst replaced
3-picoline
in which
at times
oxidation
stream vapor
and minima samples
to note,
reactor
This
on
without
for characterization
experiments,
of two
average
ammonolysis.
properties
selected
3-picoline
water
ammonolysis
the maxima
It is interesting
of
on time
6: however,
oxidative
to those
taken
ammonolysis
4+during
BET were
oxidation
surface obtained number
the area after amounted
242 to 4.65
TABLE
and
1
Changes line
4.18.
of properties
at 355'C
Sample
Time
(see
on
of the
Figure
stream
vanadium
oxide
during
Phases
detected
by XRD
Average
(minutes)
v205q
B
50 90
D
145
E
285
aReferences
Figure As we
types here
displayed profile
in the
used
from
was
been
To
study
oxidized ly on the
V02-B
[32]
3.97
28.9
profiles
study
to the
samples
ammonolysis
four
measured
under
conditions
In particular, rate
of the
parametric
the
other
reaction.
distinguishable which
hydrogen
carrier
gas
sensitivity oxides
1.
that
It should
et al.
the
vanadium
in Table
indicating
by Roozeboom
shows
flow
listed
is observed,
profile
the
for
[33]
only
peaks.
The
generally
lead
concentration
too
low.
This
of the
TPR
listed
in Table
method 1
[25].
within
the
so far. weakly
bound
X-ray
was
oxygen
was
reaction.
patterns,
be observed,
two
whereas
completely
For
sample
consumed C. which
characteristic
with
samples
peaks
D (V40g,
only
showed
in the
V02-B)
the
hydrogen
and
E (V02-B)
detected.
in air the
behaviour
(392
determined
obtained
with
reoxidized
reoxidized
for
X-ray
samples the
vanadium
vanadium
the
ammonolysis.
oxidation
E. 4.97.
about
of the
cm3/min)
oxidative
and
Furthermore,
the
measured
our
about
for
profiles
for V205
the
profiles
TPR
contribute
profile
and
high
D, 4.94: the
measured
in the
in the
during
of the
23.1
method.
reoxidation
titrimetrically
for each
4.18
was
C. 4.94:
pentoxide.
321
ammonolysis
at 38O'C
stream
[31,
TPR
too
peak
the
V02-B
of the
could
a single
10.6
whereas
the most
of V40g
consumption only
7.6
4.45
literature
TPR
50 minutes
reflexes
TPR
reported
As expected, first
4.65
311
of the
a recent
knowledge,
not
311
[30,
species
sensitivity
(66 Vol%)
[30.
V409
identification.
TPR
peak,
4.1
V409
of oxygen the
area
(m2/g)
4.98
change
that
given
To our
phase
the
of 3-pico-
surface
301a
a drastic
a single
to a low
emerges
for
9 presents
different
have
used
expected,
be noted
V409,
BET
number
[24,
v205
C
ammonolysis
oxi-
dation
0
A
oxidative
6).
same
numbers
indicated
same
BET
oxide
duration
After
diffraction
oxides,
for
this the
complete
samples.
area
samples
as they
were
reoxidation samples
patterns,
surface
the
reoxidation
re-
previous-
procedure,
were:
as well
were
B. 4.95:
as TPR
profiles,
to vanadium
(7 to 8 m'/g)
was
measured
245 Ammoxidation
on vanadium
oxides
To study
the
activity
and
lar oxygen,
the
vanadium
oxide
(Figure dard
6 and
Table
conditions.
a few the
minutes,
duration
ed with
the
1) were
With and
all
of different
selectivity samples
employed
formed for
experiments,
no deactivation
of the
experiments.
different
vanadium
the
of
was
during
the
during
free
under
attained
minutes,
product
molecu-
ammonolysis
were
ninety
the
of
of 3-picoline
conditions
10 presents when
presence oxidative
ammoxidation
observed
samples
reduction
in the
steady-state
Figure oxide
degrees
behaviour
which
distribution
steady-state
conditions
stanwithin was obtain-
were
at-
tained. Samples
A (V205),
6 (V205,
of 3-cyanopyridine was
(60%)
significantly
hibited
the
lowest
total
oxidation.
oxide
samples
TABLE
2
Comparison
Sample
selectivity
Table
during
of
the
Phases
B
diffraction
'2'5.
B*a
the
Average
&
v409
D
V02-B
v4oq.
D*
V205' *
E
V02-B
E"
V60,3
aSamples
after
bPrevailing
All phase
phases
samples changes
use
VO2-B
i30.341
for
the
are
underlined.
exhibited were
due
oxide and
an
observed
Sample Sample
shown
samples after
maximum D (V409,
E (VO2-B)
to preferentially properties
reduced their
vanadium
10.
during
use
yields VO -6) 2 ex-
catalyzing
of the
in Figure
oxidation
BET
number
v409
C"
samples.
in the
experiments
6) before
comparable
for
the
the
oxidative
ammoxida-
10).
v2°5qv409
C
former
changes
vanadium
(Figure
by
the
provided
distributions.
to 3-cyanopyridine
of the
(Figure
C (V409)
product
ammoxidation
detected
X-ray
and
than
2 contains
3-picoline
of 3-picoline
V409) similar
selective
of properties
ammonolysis tion
less
and
4.65
1.6
4.83
6.5
4.45
10.6
4.53
5.6
4.18
23.1
4.56
9.7
3.91
28.9
4.51
5.8
increase
area
(m'/g)
ammoxidation
with
surface
of 3-picoline
in the
samples
average
D and
are marked
oxidation
E. Sample
with
number.
D, initially
*.
Drastic consisting
246 of V409
and
E (VO2-B), B.
VO2-5, was
in which
sured
for
agreement The
the
BET
V205
the
drastic
oxide
X-ray
results
vanadium
in the
BET
use
which
before
28.9
texture and
area
to
was
VO2-B;
sample
with
sample
TPR
profiles
were
mea-
in excellent
2.
took
place
during
samples,
ammoxidation
observed
5.8 m2/g
and
observed
ammoxidation
of the
after
V409
were
ammoxidation.
in the
in Table
oxides, of the
surface
from
of V205, changes
during
after
summarized
measured
decreased
a mixture Moderate
increased
alteration
areas
change area
into
VbOT3.
samples
of the
a marked
surface
surface
into
concentration
changes
caused
by the
transformed
vanadium
with
phase
dation,
most
the
the
was
transformed
due
with
to the
the
as
(Table sample
phase
ammoxi-
is indicated 2).
The
E, for which
transformation.
DISCUSSION Ammoxidation For
the
pyridine
of alkylpyridines ammoxidation
(Figure
ty behaviour. takes the
place
vanadium
(Figure
4).
position The
pentoxide This
of the
of water
has
for
behaviour
However,
kylpyridine gen
[351.
of
and
trimetric oxide
by the than
ascribed
that
this
vapor
factor
is much
plays
oxidation
the methyl group
of the
group
aromatic
present
that
stage
it has
been
shown
than
with
the
the
The
of the
dealkylation
faster for
5.
pyridine
to 3-cyanopyridine.
a role
in
in position
5 indicates
oxidative
Furthermore,
water
selectivi-
oxidation.
2 and
at the
to enhanced
of water. with
ethyl
total
selectivity
understood
and
selective
3-cyanopyridine
that
to a weakening
in Figures
on the
completely
towards
fact the
i.e.
activity that
of 3-ethyl-
of 2-methyl-5-ethylpyridine
selectivity
lead
presented
similar
ammoxidation
poor
ammoxidation
observation
oxidation
may
influence
presence
changed
The oxide
its after
mainly
Oxidative
give
during
TPR
selected
properties
use
reason work.
of the
that pure
the
al-
oxy-
oxygen
selectivity
behaviour
nor
gave
temperature
any
have
been
that
Evidently
ammoxidation.
must
programmed
indication
very
low and
the
the
reduction, vanadium
reduction
undetectable
ti-
pent-
degree
of
by methods
information.
of alkylpyridines
oxidative
the
activity
on vanadium and
ammonolysis
species
(Figure during
analysis
during
reaction
bulk
of oxygen
times
X-ray
measurements
instationary
the
profiles
area
the
ammonolysis
observed
existence
neither
out,
or surface
samples
which
The
the
the
v205. As pointed
all
results
of V2O5
it is likely
showed
general
be understood
group
be partially
rate
only
2) and
its decomposition,
is not
in the
exchange
For
towards
methyl
a negative
it can
may
enhances
of the
the
atom.
exhibited
pentoxide
(Figure
pentoxide
supports
reactive
which
A comparison
this
vanadium
behaviour
2 is more
system
the
result
at the o-carbon
oxidation
ring
3).
This
on vanadium
of 3-picoline
of different
9) of the oxidative
pantoxide
selectivity
behaviour
of alkylpyridines specific
vanadium
activity
oxide
ammonolysis
samples
can
of the
on the taken
of 3-picoline
vanadium
be explained
by the
catalyst
from
the
indicate
surface. reactor
that
at
diffe-
241 rently
bound
ly bound
oxygen
oxygen
first
50 minutes
sumed
to
ary
to reduce
measured
for
vanadium
oxidation
files
(Figure
in a V5+ The nied
samples
the
V4+
state
structural
changes
E. The
the the
during
by an
increase
in the
total
this
increase
in the
surface
vity.
Maximum
conversion
the
X-ray
30%
3-cyanopyridine.
V409
diffraction
A slightly
production of all low
As
pattern:
and
single
and
expected,
replacement
to a higher
between
the
instationary
(Figure
6) and oxide
pyridine
The than the
one
ethyl
ethylpyridine
that
prevail.
was was
became
cannot
used
result
more
profiles average
the
TPR
pro-
the
vanadium
to V02-B
were
accompa-
by the
phases
or V409/V02-B. was
is
was
the
were
The
most
acti-
evident
highest with
due
in
yield
of
V205/
to significant
active
in particular,
How-
catalyst
obtained
by V409/V02-B
VP05
BET method.
in a higher
selectivity,
more
observed.
to the
and
selective
VO -B exhibited 2
fact
ammonolysis
rapidly
and
enough less
oxidative
the
fact
both
the
performed
the
for
towards
much
dehydrogenation
va-
3-cyano-
less
no
selective
dehydrogenation formation
the
vanadium
water
the
of water,
oxide,
of
of 3-vinyl-
ammonolysis
3-picoline.
per mol
with
that
absence
7) was
oxidative
A comparison
indicates
to the
with
by the oxygen
8).
oxidative
that
than
with
selective
In
leading
is required
8)
(Figure
that
by the
also
(Figure
ammonolysis.
reaction,
requires
is the
led
(Figure
active
the
oxygen
which
this
water
for
dominant
be supplied
case
oxidative
was
be explained
as much
by nitrogen
of 3-ethylpyridine due
the can
reaction
In our
V205
co-existing
and,
without
considerably
ammonolysis
result
the
that
con-
necess-
the
TPR
of the
indicate
to 3-cyanopyridine
of the
production
twice
oxygen
sumed
water
course
of 3-picoline,
This
of the
selectivity
conducted
no water
group
pyridine.
one
pyridine
oxidative
the
that
the
catalyst
when
significant
two
products. V 0 49
oxygen,
1) and
as measured
not
exhibited
oxides.
hydrogen amount
by the
(Table
weak-
in the
selectivity.
ammonolysis
nadium
was
bound
measurements
from
V,O,/V,O,
to 70%
tarry
phase
did
when
either
selectivity
of pyridine
activity
measured
the
to the
is indicated
samples
area
area
that
place
ammonolysis.
reduction
surface
corresponding
lower
examined
was
weakly
of the most
takes
exactly
results
different
the
to note
titrimetric
analysis
oxidative
ever,
as
Removal
9) already
of the
important
X-ray
with
during
reaction.
corresponded
depletion
to be
B. C. D and number,
9) obtained
and
oxygen
After
started
in the
A in Figure
It is interesting
bound
to V6013.
oxygen
involved
of profile
reaction.
the weakly
V205
bound
are
peak
of the
remove
strongly
species
(first
In the
of 3case
it is pre-
of 3-ethylpyridine
will
of 3-ethylpyridine
to
3-vinylpyridine. Our portant
experiments reduction
conditions active
(Table step
applied,
state
of the
the
1) indicate
for
oxidative
reduction
vanadium
that
reduction
ammonolysis.
of the
oxide.
the
V205
from
Regardless
always
led
V
5+
to V4'
of the
to V02-6
is the
im-
experimental
as the
final
in-
248 Ammoxidation The and
on vanadium
results
C (V40,)
into and
displayed
account V4OB
that
This
some
of the
displayed
V409
our
results
Lundin
haviour
can
be noted.
yield
kylpyridines
X-ray
analysis with
to have
a slightly VO2-B.
E underwent
the most listed
results
it appears used.
investigations
nothing
to the
ammoxidation
ted
that
V02-B
sample
indicated
the
amount
V02-B,
towards
changes 2. Only
V6013
probably
V6013
of Andersson
more and
oxidation be concluded
experiments. is inactive
exhibited the
bea ma-
maximum
temperature, of our
grain
V205
at can
morphology
ammoxidation
on of al-
find
significant
be mentioned
of V60,3q formed
which
was
changes that
were
not
apparently
the de-
too
small
prevailing, Sample
exhibited
E containing
as sample
D. how-
at 365'C.
Sample
the
was
ammoxidation
detected and
its
intrinsic experiment
is apparent analysis
stable
would
Indication
( sample
as
by X-ray
relatively
V02-B
the
phase
at 365'C.
have
for
E) under activity presented
phase
from
after
use.
under
the
to be used
this
the and
emerges
to perfrom
conditions selctivity
in Figure
are due
to
LONZA
from
6 indica-
ammonolysis.
for
financially
supporting
this
the
used,
ACKNOWLEDGEMENT Thanks
be
(35%)
of the
Switzerland
by An-
selectivity
active
[Zl].
AG.
reported
similarly
Lundin
oxidative
not
latter
temperatures
for
in which dominant,
3-cyanopyridine
selectively.
about
V205)
(A) pha-
became
V205,
for
it should
or V409
active
However,
of the
we did
the
during
lower
V205
to both
laboratory.
traces
was
V6013
is a very
our lower
selectivity
of V6013
V205
selective
Taking
for
and yields.
with
than
V205
catalysts
in our
[21],
on conversion
for
influence
Although,
analysis,
drastic
with
can
use.
by X-ray
However,
decisive
our
Lundin
and
in Table
rapid
and
and
that
at a much
pentoxide
after
selectivity
that
ammoxidation
Owing
V409
less
The
those
activity
found
and
V205)
phase.
whereas,
activity
investigated
However, effect
lower
the
V205
they
phase
2) with
in the
appeared
morphology.
being
used
as detected
and
of vanadium
Andersson
sample.
considerably
conditions
grain
D containing
only
form
higher
of their
our
only
Thus,
the
of the
a significant
Sample
ever,
with
properties
tected
that
selectivity
(Figure
at 458'C,
60%
is presently
In agreement of the
of 34% was
to a different and
V205
B (V409,
latter
pure
analysis
selectivity
sample
the
as the
difference
yield
We believe
activity
with
that
B (V408,
at 365'c.
by X-ray
a similar
that
investigation,
of 3-cyanopyridine
37O'C.
ascribed the
In their
fact
such
selectivity
a striking
A (V205),
to 3-cyanopyridine
ascribe
by the
to V205, and
of reduction
samples
be detected
we may
obtained
[21].
3-cyanopyridine
about
could
2).
activity
and
of the
(Table
degrees that
selectivity
changes
converted
dersson
ximum
10 show
substantiated
was
a similar
Comparing
a similar
use
is further
of different
in Figure
no phase
(C) after
ses.
oxides
presented
work.
243
+ "409
-
800
700
V40g + V02-B
1000
900
TEMPERATURE(K> FIGURE
9
have
been
line
shown
Reduction
profiles
on
for
stream
in Figure
(TPR)
different
6. TPR
measured times
conditions:
for
vanadium
pentoxide
during
the
oxidative
sample
weig'ht. 75 mg:
samples
ammonolysis heating
which
of 3-picorate,
10 Umin.
Note
the
different
ammonolysis
specific
oxide
of the
In Figure
areas
shown
surface
of 3-picoline
on vanadium
which
samples
(Table
6. Ammoxidation
samples
C
B
A
of 3-picoline
123456
123456
123456
nn been
2).
see
reduced conditions
have
D
123456
.
I,L
.
1, CONVERSION, 2, 3-CYANOPYRIDINE, 3, PYRIDINE, 4. CARBONDIOXIDE,5, CARBONMON102 IE,6. TAR
I
I
Ammoxidation
oxidative
365'C.
the
FIGURE IO
100
during temperature
degrees 2: reaction
to different Figure
E
123456
hl
249
REFERENCES H. Kating, Pharm. Ztg., 23 (1968) 810. Brit. Pat. 1973. 1317064. A. Andersson. J. Catal., 69 (1981) 465. K. Watanabe, Bull. Chem. Sot. Japan, 37 (1964) 1325. Ger. Pat. 1975, 2517053. B.V. Suvorov, A.O. Kagarlitskii. N.V. Suslova and Y.G. 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 :a 25 ;;
Efremov,
Prikl.
Khim.,
45 (1972) 2588. Ger. Pat. 1975. 2435134. Ger. Pat. 1972. 1940320. H. Beschke. H. Friedrich. H. Schaefer and G. Schreyer, Chem. Ztg., 101 (1977) 384. B.V. Suvorov, A.O. Kagarlitskii, G.K. Kryukov. E.M. Guseinov and N.R. Bukeihanov, Kinet. Katal.. 15 (1974) 1507. B.V. Suvorov, A.O. Kagarlitskii, O.K. Sembaev and A.I. Loiko. Kinet.Katal., 19 (1978) 197. B.V. Suvorov, V.A. Yakovlev. A.O. Kagarlitskii. E.M. Guseinov. R.T. Kutzhanov, 1.1. Kan and O.B. Lebedeva. Khim Farm. Zh.. 10 (1976) 83. B.V. Suvorov. A-0. Kagarlitskii, 1.1. Kan and R.T. Kutzhanov. Kinet. Katal.. 18 (1977) 957. R. Prasad and A.K. Kar. Ind. Eng. Chem. Proc. Des. Oev.. 15 (1976) 170. A. Oas and A.K. Kar. Ind. Eng. Chem. Proc. Des. Oev.. 19 (1980) 689. S. Kumar and S.Z. Hussain, Chem. Eng. Sci., 35 (1980) 1425. R. Prasad and A.K. Kar. Indian J. Technol.. 15 (1977) 288. A. Andersson and S.T. Lundin, J. Catal., 65 (1980) 9. S.L.T. Andersson and S.J. Jarbs. J. Catal., 64 (1980) 51. S.L.T. Andersson. J.C.S. Faraday Trans.1.. 75 (1979) 1356. A. Andersson and S.T. Lundin. J. Catal.. 58 (1979) 383. M.C. Sze and A. P. Gelbein. Hydrocarbon Process., 55(1976) 103. J. Zi6lkowski and J. Janas. J. Catal.. 81 (1983) 298. ASTM Powder Diffraction File, 9-387, Ed. Joint Commitee on Powder Diffraction Standards, Pennsylvania, 1980. 0. M. Monti and A. Baiker. J. Catal.. 83 (1983) 323. M. Nakamura. K. Kawai and.Y. Fujiwara. J.‘Cataj.. 34 (1974) 345. O.R. Stull. E.F. Westrum and G.C. Sinke. The Chemical Thermodynamics of Drganic Compounds, Wiley, New York, 1969. S.W. Benson, Thermochemical Kinetics, Wiley, New York, 1976. P. Zollinger, Ph.D.-Thesis, ETH-Zurich. 1982. L. Fiersman. P. Clauws and W. Oekeyser. Can. Mineral. 16 (1978) 353. Reference [24], File 23-720. T. Sata and Y. Ito. Bull. Tokyo Inst. Techn.. 98 (1970) 1. F. Roozeboom. M.C. Mittelmeijer-Hazeleger, J.A. Moulin. J. Medema. V.H.J. de Beer and P.J. Gellings, J. Phys. Chem., 84 (1980) 2783. Reference [24]. File 27-1318. W.C. Cameron, A. Farkas and L.M. Litz, J. Phys. Chem. 57 (1953) 229.
Applied Catalysis, 10 (1984) 231-249 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands
AMMOXIDATION
ALFONS
BAIKER
Swiss and
OF ALKYLPYRIDINES
and
Federal
Institute
Engineering
(Received
PETER
AND
WITHOUT
OXYGEN
ZOLLINGER of Technology
Chemistry,
6 January
OXIDES WITH
ON VANADIUM
1984,
CH-8092
accepted
(ETH).
Zurich.
Department
of
Industrial
Switzerland.
16 March
1984)
ABSTRACT The ammoxidation of 3-alkylpyridines on unsupported, unpromoted vanadium oxides has been investigated in the presence and in the absence of molecular oxygen. The latter reaction, resulting in the reduction of the vanadium oxide. was termed oxidative ammonolysis. Reactyons were performed under nearly isothermal conditions in a microscale fluidized bed reactor in the temoerature ranae from 250' to 45O'C. Vanadium oxides were characterized by X-ray analysis, TPR. BET and titrimetric measurements. Ammoxidation of 3-picoline on V205.gave a maximum yield of 60% 3cyanopyridine at 370°C, corresponding to 90% conversion. VA09 exhibited a similar ._ selectivity as V2O5. VO2 was active, -but nonselective, and'converted rapidly to under ammoxidation conditions. Of the multiple phase oxides, V205/V4Og and '6'1 V4Og?VO2 showed a selectivity comparable to the single phase oxides, V2O5 and V4Og; however, their properties changed under ammoxidation conditions. 3-ethylpyridine was ammoxidized with comparable activity and selectivity as 3-picoline. In contrast, ammoxidation of 2-methyl-5-ethylpyridine gave a maximum yield of only 25% 3-cyanopyridine. due to enhanced destruction of the pyridine ring.
INTRODUCTION Ammoxidation pyridine in the tinic
has
gained
synthesis acid
portant
are
part
tained
hydration
of more acid
line
but
[8],
Research [9] and
than
90%
can
are
supported
Probably
0166-9834/84/$03.00
the
most
because
of the
nicotinamide
[4-61
and for
hydrolysis both
also
or,
reports pentoxides
[l].
The [2.3]
and
by direct to those
[lo-211. have
of the
has
can
been oxides
are
intrinsic
0 1984 Elsevier Science Publishers B.V.
into
very
im-
by
nicotinic
acid with
respectively.
oxidation
studies,
nico-
an ob-
be performed
acid,
prompted
employed
plays
be transformed
ammoxidation
In most
step and
3-cyanopyridine
vapor-phase
of the
a decisive
which
can
nicotinic
to 3-cyano-
nicotinamide
by hydrolysis,
of 3-cyanopyridine
vanadium
studies
Both
B complex
up to 85%
of alkylpyridines
unpromoted
detailed
vitamin
nicotinamide
low compared
vanadium
acid.
and mammals yields
of 3-picoline
it constitutes
nicotinic
with
scientific
on unsupported,
of
of men
step
ammoxidation
of
in particular,
interest and
be synthesized
yields
on the
a series
and
studies
metabolism
into
and,
to be parts
ammoxidation
hydration
Nicotinic
moted
considered
Catalytic
yields
considerable
of nicotinamide
in the
by the
catalytic [7].
of 3-alkylpyridines
of 3-pico-
route.
numerous
patents
differently
as catalysts,
pro-
whereas
scarce.
activity
and
specificity
232 of vanadium
oxides
carried
by Andersson
out
nadium
oxides,
active
and
both
phases, menon the
selective
they
the
This
latter
work.
Oxygen
oxidative Special
haviour
of the
of the
phase
when
of the
found
oxides
so far,
that and
to V204
phase
boundary
V6013
that
was
those
the
the
V60,3
reaction.
of both oxides.
surfaces
are
of different
during
consisting
single
of active
reported
investigations
they
reduced
is carried the
type
required
for the
resulting
of
V205
The
was
Further-
and
V60,3
latter
which
vamost
pheno-
accompanied
will
was
devoted
the
presence
also
of molecular
be performed
be termed
oxidative
oxygen;
without
"oxidative
ammonolysis
molecul-
ammonolysis" reaction
is sup-
in its reduction.
work
vanadium
during
in the can
to
investigate
3-alkylpyridines
was
different
out
reaction
reaction
present
emphasis
properties
any
that
catalyst,
ammonolysis
oxides.
single
their
phases.
[22].
objective
V204.
catalyst,
than
ammoxidation
the
and
extent
creation
shown
present
catalyst
V6013
been
by the
The
the
it has
ar oxygen in the
the
In
of the
to some
of 3-picoline.
[Zl].
V6013
and
to the
of new
Generally however,
Lundin
V205.
selective
ascribed
formation
plied
that
more
ammoxidation
and
catalyst
to V205
found
was
was
the
including
oxidized
more,
for
the
ammoxidation
on unpromoted,
unsupported
to examining
oxides
course
and
of
to
the
activity
and
investigating
the
as well
as
vanadium
selectivity changes
be-
in the
reaction.
EXPERIMENTAL Catalyst Pure sent 4.6
vanadium
pentoxide
investigation. m2/g;
solid
as measured ticle
size. ning
For the
reement lues
/Iolo
intensities
with
g/cm3:
consisted
specific
were:
3.40 pore
of agglomerates
presented defined
of the
pentoxide
nonoriented
plates
in Figure
by Zihlkowski
X-ray
calculated
in the
action
were
(TPR),
titrimetric
relco
pentoxide
was
used
BET
surface apparent
g/cm3;
volume,
in the
0.258
pre-
area, density
cm3/g;
par-
lines
used, for
for
f was
of grains
as becomes
1 and and the
the
Janas
found
less
than
from
1 pm
the
scan-
determined
morphological
[23].
and
respective
[24]
I,o,
planes
to be 0.95
a monocrystal
of
evident
and
which with
Iolo
given
are
the
by the
in-
is in good
experimental
agva-
samples.
characterization
Changes
electron
vanadium
Switzerland
urn.
vanadium
for
AG,
by He-pycnometry,
1.81
f = 0.90
obtained
Catalyst
of the
not well-developed
micrograph
f = I,o,
measured
120-250
were
by Fluka
as measured
pentoxide
grains
electron
factor
dex.
range,
vanadium The
Properties
density
by Hg-pycnometry,
size
The
supplied
physical
and
characterized
microscopy.
(Philips)
methods, The
chemical
by X-ray nitrogen
X-ray
diffractometer
properties
diffraction, adsorption
diffraction using
CuKa
of the
vanadium
temperature measurements
measurements radiation.
The
were
oxide
programmed (BET)
and
performed
apparatus
used
during
re-
reduction scanning with for
a Nothe
233 TPR
measurements
has
obtained
under
hydrogen
in nitrogen
The
average
[26]
using
FIGURE and
the
been
oxidation
1
Scanning
number
rate
of the
permanganate
electron
ammonolysis
previously
conditions:
at a flow
potassium
oxidative
described
following
[25].
sample
The
weight,
of 75 cm3(NTP)/min; vanadium
and
micrograph
iron
was
TPR-profiles
shown
were
75 mg;
reducing
gas,
heating
rate,
lO'C/min.
determined
by titrimetric
6%
methods
sulfate.
of vanadium
pentoxide
used
in ammoxidation
experiments.
Reactants Air,
ammonia
mercially (98%.
available
supplier
pyridine The
Apparatus The
was
Lonza
impurity
and
2 cm
installed
nitrogen gas
cylinders.
3-ethylpyridine
AG),
of the
were
fed
The
(99.5%.
to the
3-picoline
were
(99.99%)
was
fed
liquid
Fluka
reactor
to the
reactants,
AG)
and
without
4-picoline
reactor
from
com-
3-picoline
2-methyl-5-ethyl-
further
purification.
(1.5%).
procedures
experiments and
and
compressed
Reilly),
(99%.
major
length
(99.99%)
were
inner
in a gas
performed
diameter.
in a microscale For
chromatograph
temperature oven.
fluidized control,
Temperatures
bed
this in the
reactor
Pyrex
of
glass
fluidized
18 cm reactor
bed were
234 monitored water
with
were
dosed
ed through actants ous
0.5
and
products,
products
and
stream
Experiments reaction
precision
shown
tions:
amount
monia,
0.86;
in this
were
air,
without
conditions,
the
reaction
molecular
the
air
was
and
under
reactor
following
oxygen)
replaced
oxidative
were
was
standard
condi-
0.26;
am-
ammonolysis
performed
fed
ammoxldatlon
in mmol/min:alkylpyridine, The
(1 Mel/l). desired
reactor
The
re-
nongase-
to the
the
pass-
of
ammonia
cm3/min)
nitrogen. the
the
and
The
the of
temperature,
air
5003)
heated.
solution (250
and
condensation
by passing
air
392 cm3(NTP)/min.
free
but with
tubing
V205in
rates
Precidor.
To avoid
absorbed
conducted
alkylpyridines
(Infors
an aqueous
water,
10 g; feed
10.14;
were
the
ammonia,
paper
of catalyst,
(ammoxidation
standard
reaching
The
reactor.
and outlet
containing
by heating
After
pumps
the
alkylpyridine
started
water,
infusion
inlet
bubblers
of alkylpyridlne,
experiments
thermocouples.
entering
reactor
unreacted through
were
NiCr/Ni
before
the
temperature.
mixture
ments
by high
an evaporator
effluent
the
mm diameter
under
experi-
the
same
by nitrogen.
Analysis The
unreacted
temperature a 5% SP-1000 dinitrlle carrier 250°C
on
was gas;
with
monoxide
employed
bon dioxide
carbon
ous
phases
total
CT
mass
n
carbon flow
the
identified
+
was barium
wac_ used
as
linearly
products,
carbon
dioxide
To determine
mixed
effluent
acid
with
carbonate gas was
was the
enough
to
carbon
car-
aqueous
measured measured
graviwith
was
every CT
performed
an
15 minutes
In the
for
integral
effluent
tarry
each
analysis
experiment. of the
during
the
stream
of the
To collect
condensed
experiments.
The
reactor
the
and gasenormalized
is given
by eq.
1):
z i
of product
total
The
a
with
Succinlc
raised
oxidation
with
equipped
2 m).
was
solution.
solution
analyzed
900)
(30 cm3/min) 100°C.
separately.
of the
Mod
length
total
product
precipitated
content
at
gaseous
are the molar flow rates and n p,in p-out atoms at the reactor inlet and outlet,
rate
in the
The
product
balance,
conducted
"p,in
where
and
balance
this
of carbon
"p,out
=
starting
analyzed
20 ml of the
4 mm. helium
standard:
ammoniacal
monoxide
(i.d.
were
Elmer,
tubes.
for
was
amount
were
in the
products
(Perkin
column
of 8'C/min.
chloride
carbon
necessary
nongaseous
temperature,
dioxide,
carbon
detector
A total data
The
the
as an internal column
absorbed
of barium
and
chromatograph
Supelcoport
rate
content,
metrically. Drager
the
a heating
and
gas
lOO/lZO
and
quantitatively
solution
alkylpyridine
programmable
i containing
by-products,
carbon
mass
all
balance.
Bi carbon products The yield
of the
alkylpyridine
respectively,
atoms. were
With
the
identified
of the
tarry
and:
containing
exception and
taken
products
ai
ni is the molar of
some
into
Xtar
was
un-
account calcu-
235 lated
from
the
is defined
total
in eq.
carbon
mass
balance
using
the
relation
Xtar=l-CT,
were
CT
(1).
Definitions Conversion products
(X)
x 100.
"i.out
Bi
"p,in
oi
xi =
The
selectivity
and
totally
is defined
The
yield
as the
, Xi,
fraction
of the
of a specific
alkylpyridine
product
converted
is defined
by eq.
into
(2):
1oo
(X)
is the
converted
ratio
of alkylpyridine
converted
to a specific
product
x 100.
RESULTS Ammoxidation The oxide and
of alkylpyridines
ammoxidation were
on
reactions
investigated.
For
the
plotted
as a function
the
three
highest
dine
the
selectivity
amounted
yield
tivity
to 60%
was 4):
at total only
the
not
ditions
ammoxidation
in the the
case
tion -1820
was
with
species,
reactions: for
we -495
of 60%.
yield
respectively. exhibited of 3-cyanopyri-
selectivity
comparable
at about
corresponding
and
carbon
yield
carbon
in the
In con-
vanadium
pentoxide
90 minutes,
(Figure
of 3-cyanopyridine
monoxide,
product
38O'C.
to a selec-
monoxide.
the
are
of 2-methyl-5-ethylpyridine
and
during of
[27]
2-cyano-5-ethyl
mixture.
no marked
Within
change
was
for
the
the
the
Z-methyl-5-ethylpyridine.
the
temperature
of 3-picoline. reaction.
reaction
and
calculated
and
to control
ammoxidation
kJ/mol
maximum
the maximum
found
about
4,
and
3-picoline
3-ethylpyridine;
dioxide
dioxide were
2.3,
3-ethylpyridine,
3-ethylpyridine
heats
data
and
of 3-ethylpyridine, products
and
pent-
dura-
observed
selectivity.
required
the
in the
literature
kJ/mol
of
be maintained
ked differences
maining
feed
(~2%)
and
of
ammoxidation
generally
activity
carbon
at 4OO'C.
to carbon
pyridine
experiments,
could
By using
and
were
the
on vanadium
reaction
of
activity
its maximum
3-picoline the
An
ammoxidation
reached
for
in Figures
ammoxidation (67%):
at 37O'C. the
reached
In addition
(~5%)~
of water was
selective
catalyst
For
for
with
conversion,
25%.
of the
in the
occured
by-products
reactions
weakly
was
pyridine
and
3-picoline.
of the major
temperature the
alkylpyridines
of
yields
to 3-cyanopyridine
observed
Major
pentoxide
different
reactions,
of 3-cyanopyridine
to the
only
tion
was
of 65%.
trast
reaction
ammoxldation
to 3-picoline the
of
three
ammoxidation
of Z-methyl-5-ethylpyridine,
Of these
vanadium
for
for
the
incremental
following
3-picoline.
Z-methyl-5-ethylpyridine.
This
where
behavlour
ammoxidation method
enthalpies -1107
in the nearly
kJ/mol
reactor.
of these
at 623
use This
isothermal
is due
of Benson
for
the
mar-
compounds.
[28]
K for
con-
to the
the
for
the
re-
ammoxida-
3-ethylpyridine.
and
236
I
I
I
.*.-
/ @CONVERSION .3-CYANOPYRIDINE./ aCARBON MONOXIDE oTAR vCARBON DIOXIDE
*
/
450
400
350
300
250
TEMPERATURE('0
FIGURE sion
2
Ammoxidation
and
yields
particle
size
ammonia,
0.86:
in the under and
these
those
This
the
for
before
and
water
reaction
after
surface of the
(392
vapor
same
the
Figure
maximum
yield with
diffraction,
measurements.
vanadium
pentoxide
of V205,
10 g;
3-plcollne,
that
use
the
of 73%
to an 80% 60%
in the
0.26;
changed
but
3-picoline, the water
results
with
(Figure
decreased
3-cyanopyrldine
selectivity
and
a 67%
vapor
obtained
water
of water
ex-
2)
the
obtained
to 3-cyanopy-
selectivity
to
feed.
experiments,
These
of
the
obtained
temperature
area
conditions, 5 presents
results
of only
water
ammoxidation
ammoxidation
yield
corresponds
amount
in mmol/min:
of conver--
cm3/min).
standard
of the
Dependence
conditions:
rates
on the
5) indicates The
to a maximum the
by X-ray BET
properties
ments.
the
feed
by nitrogen.
(Figure
without
compares
17.47
A comparison
water
experiments
and
under
substituted
pentoxide.
Standard
pm;
of water
to 3-cyanopyridine.
characterized methods
air,
influence
conditions.
3-cyanopyridine Both
120-250
10.14;
conducted
was
without
selectivity
ridine.
the
on vanadium
temperature.
of V205'
water,
were
feed
in the
on reaction
range
To examine periments
of 3-picoline
the
programmed methods during
vanadium reduction,
gave the
no
pentoxides
were
titrimetric
indication
ammoxidation
that
experi-
231
100
I
I
a-
.).
*CONVERSION s
/
80-
m 9 g
l
/ 60-
i
n 3-CYANOPYRIDINE ..'
vCARBON DIOXIDE \ z qCARBONMONOXID J 8 40- oTAR 5; i!zl / -0-o h Lo_o-+ s 20' f o/zvm q:v 0 rraalnfllcllm'lm*a* 350 300 250
.\
_
450
400
TEMPERATURE('C)
FIGURE on
3
reaction
Ammoxidation temperature.
of 3-ethylpyridine. Standard
Dependence
conditions,
see
of conversion
Figure
and
of yields
2.
*CONVERSION
v 2-CYANO-5-ETHYL-
250
300
350
400
450
TEMPERATURE('C)
FIGURE
4
Ammoxidation
yields
on
reaction
of 2-methyl-5-ethylpyridine.
temperature.
Standard
conditions,
Dependence see
Figure
of conversion 2.
and
of
238
100
I
I
. CONVERSION n 3-CYANOPYRIDINE ‘v CARBON DIOXIDE 0 CARBON MONOXIDE 0 TAR
80
I
Jet ./ m-m
\
n
400
350
300
250
TEMPERATURE
FIGURE
5
version
Ammoxidation and
yields
however,water
Oxidative The
on
vapor
reaction
replaced
ammonolysis
oxidative that
the
amount
of nitrogen
the
in the
vanadium
on
experiments
normally
and
water
temperature.
of alkylpyridines
air,
3-ethylpyridine,
without
in the
Standard
feed.
conditions
Dependence (see
of con-
Figure
2);
by nitrogen.
ammonolysis
except
pound,
of 3-picoline
(‘C >
used
feed.
for
The
vanadium
were the
oxidative
exhibited
under
ammoxidation,
was
ammonolysis
Z-methyl-5-ethylpyridine pentoxide
pentoxide
performed
were
standard replaced
reactions
investigated,
an instationary
of 3-picoline,
With
behaviour
conditions, by an equal
each
com-
in activity
and
selectivity. Figure
6 depicts
coline
at 355'C.
higher
temperatures
observed first
hours
the the
instationary
Two
with
two
appeared second
after
became
of the
behaviour
distinct
maxima
separate
maxima
about
maximum,
catalyst
course
instationary
[29].
to coincide
maximum
Following five
the
A similar
the
50 minutes activity
almost
oxidative of this
ammonolysis
reaction
in the
3-cyanopyridine
in the
3-picoline
and
the
decreased
completely
second
inactive.
of
3-p1-
occured
at
yield
were
conversion.
The
after
continuously
also
145 minutes. until
after
about
239
50 CONVERSION n 3-CYANOPYRIDINE v PYRIDINE l
\
I
0 60
0
120
180
240
300
360
TIME ON STREAM (MINUTES)
FIGURE and
Oxidative
6
yields
on time
particle
size
ammonia,
0.86;
the
of the
formation
complete
duction
of the
Figure
lost
the
Compared
towards
3-vinylpyridine.
the with more
nitrogen,
Standard
17. 47
by-products,
by-products. from
was
due
3-cyanopyridine similar
of
to the was
and
tar,
experiments, the
total
the
observed
the
of V205,
3-picoline,
the
(Figure
due
oxidative
the
10 g
0.26;
second
that
re-
conditions
6) the
of
used. 3-ethyl-
vanadium required.
to a significant ammonolysis
consumed
further
ammonolysis
consumption
enhanced
at different
of oxygen
ammonolysis
oxygen
mainly
with
temperature
performed amount
for
3-picoline
low,
amount
peaked
indicating
under
conditions,
conversion
cm3/min).
Increasing
higher
of
in mmol/min:
constant,
course
ammonolysis
rapidly,
Under
was
impossible
instationary the
all
to 411'C.
deactivation oxide
(392
yield.
Dependence
conditions:
rates
pyridine
With
355'
at 355'C.
urn; feed
3-cyanopyridine
range
vanadium
its activity
selectivity of
major
catalyst
7 depicts
120-250
10.14:
of these in the
before
pyridine.
for
of 3-picoline
of catalyst.
of V205,
water,
observed
temperatures
on stream
range
Production maximum
ammonolysis
oxide The
production
performed
with
240 Z-methyl-5-ethylpyridine the maximum
yield
of by-products
also
showed
an
of 3-cyanopyridine
such
as carbon
2-cyano-5-ethylpyridine
and
instationary
was
dioxide,
only
about
carbon
course
of the
5%. due
to the
monoxide,
pyridine.
reaction, large
but
production
3_ethylpyridine,
tar.
I
I
I
I
. CONVERSION n 3-CYANOPYRIDINE r3-VINYLPYRIDINE v CARBON DIOXIDE qCARBON MONOXIDE
0
I 60
0
TIME FIGURE sion
7
and
The
Oxidative yields
of water
shown
8. A similar
where
the
reaction
comparison
of the
significantly fed
to the
ne.
the
about To ges
on
more
in the
was
physical
the
latter
more
with
vapor
this
in the
6 and 8 reveals selective
80%;
in the
feed are
is observed (Figure
that
the
at the maximum with
yield water
Figure
and
6).
of 60%
the
in-
in Fi-
in the
case
However,
vanadium when
was
6.
repeating
plotted as
feed
to 3-cyanopyridine
whereas,
see
of 3-picoline
experiment
reaction
water
conditions,
of conver-
oxide no water
a was was
3-cyanopyridi-
maximum
yield
was
selectivity.
of the
chemical
from
Dependence
ammonolysis
the water
of the
case,
than
to 70%
source
and
out
and more
In the
corresponding
investigate
course
at 355'C.
Standard
oxidative
for
in Figures
active
reactor.
on the
6. Results
carried
results
(MINUTES)
of catalyst.
nitrogen
instationary
selectivity
30%.
stream
in Figure
was
ON STREAM
of 3-ethylpyridine
vapor
by substituting
experiment
gure
on time
influence
vestigated the
ammonolysis
240
180
120
observed
properties
instationary of the
vanadium
reaction
behaviour,
pentoxide
that
chan-
occured
241 during
reaction
duction.
characterized
were
by X-ray
and
methods,
titrimetric
BET
diffraction,
surface
I
area
temperature
I
I
programmed
re-
measurements.
I
*CONVERSION n 3-CYANOPYRIDINE
60
0
120
180
240
TIME ON STREAM (MINUTES) FIGURE
8
Oxidative
of conversion tions,
see
Table
and yields
Figure
1 contains
during
the
Figure
6, the
the
times
where
red.
The
vanadium
ning
repetitive
each
from
The
from
the
consisted
oxide
about
50 and
145
of
the
of
vanadium
that
different number
the
reaction
vanadium
and
oxide
was
as detected
of the
vanadium
changed
by an
increase
accompanied
5 to 29 m'/g.
The
highest
at the
yields
times
of
where
by
6. As
X-ray from
average
in
correspond yield
obtained
at the
B and
times
indicated
oxide
were
yield
OCCU-
by run-
desired
D. which
time.
were
in 3-cyanopyridine,
diffraction. 5+to
in the
3-cyanopyridine the
at selected
stopped
samples
condi-
of nitrogen.
vanadium
times
Dependence
Standard
3-cyanopyridine
to maximum
phases
was
i.e.,
measured
of the
feed.
amount
in Figure
to these
corresponding
change
minutes:
at 355'C.
oxide
in conversion
in the
by equal
shown
corresponding the
water
of catalyst replaced
3-picoline
in which
at times
oxidation
stream vapor
and minima samples
to note,
reactor
This
on
without
for characterization
experiments,
of two
average
ammonolysis.
properties
selected
3-picoline
water
ammonolysis
the maxima
It is interesting
of
on time
6: however,
oxidative
to those
taken
ammonolysis
4+during
BET were
oxidation
surface obtained number
the area after amounted
242 to 4.65
TABLE
and
1
Changes line
4.18.
of properties
at 355'C
Sample
Time
(see
on
of the
Figure
stream
vanadium
oxide
during
Phases
detected
by XRD
Average
(minutes)
v205q
B
50 90
D
145
E
285
aReferences
Figure As we
types here
displayed profile
in the
used
from
was
been
To
study
oxidized ly on the
V02-B
[32]
3.97
28.9
profiles
study
to the
samples
ammonolysis
four
measured
under
conditions
In particular, rate
of the
parametric
the
other
reaction.
distinguishable which
hydrogen
carrier
gas
sensitivity oxides
1.
that
It should
et al.
the
vanadium
in Table
indicating
by Roozeboom
shows
flow
listed
is observed,
profile
the
for
[33]
only
peaks.
The
generally
lead
concentration
too
low.
This
of the
TPR
listed
in Table
method 1
[25].
within
the
so far. weakly
bound
X-ray
was
oxygen
was
reaction.
patterns,
be observed,
two
whereas
completely
For
sample
consumed C. which
characteristic
with
samples
peaks
D (V40g,
only
showed
in the
V02-B)
the
hydrogen
and
E (V02-B)
detected.
in air the
behaviour
(392
determined
obtained
with
reoxidized
reoxidized
for
X-ray
samples the
vanadium
vanadium
the
ammonolysis.
oxidation
E. 4.97.
about
of the
cm3/min)
oxidative
and
Furthermore,
the
measured
our
about
for
profiles
for V205
the
profiles
TPR
contribute
profile
and
high
D, 4.94: the
measured
in the
in the
during
of the
23.1
method.
reoxidation
titrimetrically
for each
4.18
was
C. 4.94:
pentoxide.
321
ammonolysis
at 38O'C
stream
[31,
TPR
too
peak
the
V02-B
of the
could
a single
10.6
whereas
the most
of V40g
consumption only
7.6
4.45
literature
TPR
50 minutes
reflexes
TPR
reported
As expected, first
4.65
311
of the
a recent
knowledge,
not
311
[30,
species
sensitivity
(66 Vol%)
[30.
V409
identification.
TPR
peak,
4.1
V409
of oxygen the
area
(m2/g)
4.98
change
that
given
To our
phase
the
of 3-pico-
surface
301a
a drastic
a single
to a low
emerges
for
9 presents
different
have
used
expected,
be noted
V409,
BET
number
[24,
v205
C
ammonolysis
oxi-
dation
0
A
oxidative
6).
same
numbers
indicated
same
BET
oxide
duration
After
diffraction
oxides,
for
this the
complete
samples.
area
samples
as they
were
reoxidation samples
patterns,
surface
the
reoxidation
re-
previous-
procedure,
were:
as well
were
B. 4.95:
as TPR
profiles,
to vanadium
(7 to 8 m'/g)
was
measured
245 Ammoxidation
on vanadium
oxides
To study
the
activity
and
lar oxygen,
the
vanadium
oxide
(Figure dard
6 and
Table
conditions.
a few the
minutes,
duration
ed with
the
1) were
With and
all
of different
selectivity samples
employed
formed for
experiments,
no deactivation
of the
experiments.
different
vanadium
the
of
was
during
the
during
free
under
attained
minutes,
product
molecu-
ammonolysis
were
ninety
the
of
of 3-picoline
conditions
10 presents when
presence oxidative
ammoxidation
observed
samples
reduction
in the
steady-state
Figure oxide
degrees
behaviour
which
distribution
steady-state
conditions
stanwithin was obtain-
were
at-
tained. Samples
A (V205),
6 (V205,
of 3-cyanopyridine was
(60%)
significantly
hibited
the
lowest
total
oxidation.
oxide
samples
TABLE
2
Comparison
Sample
selectivity
Table
during
of
the
Phases
B
diffraction
'2'5.
B*a
the
Average
&
v409
D
V02-B
v4oq.
D*
V205' *
E
V02-B
E"
V60,3
aSamples
after
bPrevailing
All phase
phases
samples changes
use
VO2-B
i30.341
for
the
are
underlined.
exhibited were
due
oxide and
an
observed
Sample Sample
shown
samples after
maximum D (V409,
E (VO2-B)
to preferentially properties
reduced their
vanadium
10.
during
use
yields VO -6) 2 ex-
catalyzing
of the
in Figure
oxidation
BET
number
v409
C"
samples.
in the
experiments
6) before
comparable
for
the
the
oxidative
ammoxida-
10).
v2°5qv409
C
former
changes
vanadium
(Figure
by
the
provided
distributions.
to 3-cyanopyridine
of the
(Figure
C (V409)
product
ammoxidation
detected
X-ray
and
than
2 contains
3-picoline
of 3-picoline
V409) similar
selective
of properties
ammonolysis tion
less
and
4.65
1.6
4.83
6.5
4.45
10.6
4.53
5.6
4.18
23.1
4.56
9.7
3.91
28.9
4.51
5.8
increase
area
(m'/g)
ammoxidation
with
surface
of 3-picoline
in the
samples
average
D and
are marked
oxidation
E. Sample
with
number.
D, initially
*.
Drastic consisting
246 of V409
and
E (VO2-B), B.
VO2-5, was
in which
sured
for
agreement The
the
BET
V205
the
drastic
oxide
X-ray
results
vanadium
in the
BET
use
which
before
28.9
texture and
area
to
was
VO2-B;
sample
with
sample
TPR
profiles
were
mea-
in excellent
2.
took
place
during
samples,
ammoxidation
observed
5.8 m2/g
and
observed
ammoxidation
of the
after
V409
were
ammoxidation.
in the
in Table
oxides, of the
surface
from
of V205, changes
during
after
summarized
measured
decreased
a mixture Moderate
increased
alteration
areas
change area
into
VbOT3.
samples
of the
a marked
surface
surface
into
concentration
changes
caused
by the
transformed
vanadium
with
phase
dation,
most
the
the
was
transformed
due
with
to the
the
as
(Table sample
phase
ammoxi-
is indicated 2).
The
E, for which
transformation.
DISCUSSION Ammoxidation For
the
pyridine
of alkylpyridines ammoxidation
(Figure
ty behaviour. takes the
place
vanadium
(Figure
4).
position The
pentoxide This
of the
of water
has
for
behaviour
However,
kylpyridine gen
[351.
of
and
trimetric oxide
by the than
ascribed
that
this
vapor
factor
is much
plays
oxidation
the methyl group
of the
group
aromatic
present
that
stage
it has
been
shown
than
with
the
the
The
of the
dealkylation
faster for
5.
pyridine
to 3-cyanopyridine.
a role
in
in position
5 indicates
oxidative
Furthermore,
water
selectivi-
oxidation.
2 and
at the
to enhanced
of water. with
ethyl
total
selectivity
understood
and
selective
3-cyanopyridine
that
to a weakening
in Figures
on the
completely
towards
fact the
i.e.
activity that
of 3-ethyl-
of 2-methyl-5-ethylpyridine
selectivity
lead
presented
similar
ammoxidation
poor
ammoxidation
observation
oxidation
may
influence
presence
changed
The oxide
its after
mainly
Oxidative
give
during
TPR
selected
properties
use
reason work.
of the
that pure
the
al-
oxy-
oxygen
selectivity
behaviour
nor
gave
temperature
any
have
been
that
Evidently
ammoxidation.
must
programmed
indication
very
low and
the
the
reduction, vanadium
reduction
undetectable
ti-
pent-
degree
of
by methods
information.
of alkylpyridines
oxidative
the
activity
on vanadium and
ammonolysis
species
(Figure during
analysis
during
reaction
bulk
of oxygen
times
X-ray
measurements
instationary
the
profiles
area
the
ammonolysis
observed
existence
neither
out,
or surface
samples
which
The
the
the
v205. As pointed
all
results
of V2O5
it is likely
showed
general
be understood
group
be partially
rate
only
2) and
its decomposition,
is not
in the
exchange
For
towards
methyl
a negative
it can
may
enhances
of the
the
atom.
exhibited
pentoxide
(Figure
pentoxide
supports
reactive
which
A comparison
this
vanadium
behaviour
2 is more
system
the
result
at the o-carbon
oxidation
ring
3).
This
on vanadium
of 3-picoline
of different
9) of the oxidative
pantoxide
selectivity
behaviour
of alkylpyridines specific
vanadium
activity
oxide
ammonolysis
samples
can
of the
on the taken
of 3-picoline
vanadium
be explained
by the
catalyst
from
the
indicate
surface. reactor
that
at
diffe-
241 rently
bound
ly bound
oxygen
oxygen
first
50 minutes
sumed
to
ary
to reduce
measured
for
vanadium
oxidation
files
(Figure
in a V5+ The nied
samples
the
V4+
state
structural
changes
E. The
the the
during
by an
increase
in the
total
this
increase
in the
surface
vity.
Maximum
conversion
the
X-ray
30%
3-cyanopyridine.
V409
diffraction
A slightly
production of all low
As
pattern:
and
single
and
expected,
replacement
to a higher
between
the
instationary
(Figure
6) and oxide
pyridine
The than the
one
ethyl
ethylpyridine
that
prevail.
was was
became
cannot
used
result
more
profiles average
the
TPR
pro-
the
vanadium
to V02-B
were
accompa-
by the
phases
or V409/V02-B. was
is
was
the
were
The
most
acti-
evident
highest with
due
in
yield
of
V205/
to significant
active
in particular,
How-
catalyst
obtained
by V409/V02-B
VP05
BET method.
in a higher
selectivity,
more
observed.
to the
and
selective
VO -B exhibited 2
fact
ammonolysis
rapidly
and
enough less
oxidative
the
fact
both
the
performed
the
for
towards
much
dehydrogenation
va-
3-cyano-
less
no
selective
dehydrogenation formation
the
vanadium
water
the
of water,
oxide,
of
of 3-vinyl-
ammonolysis
3-picoline.
per mol
with
that
absence
7) was
oxidative
A comparison
indicates
to the
with
by the oxygen
8).
oxidative
that
than
with
selective
In
leading
is required
8)
(Figure
that
by the
also
(Figure
ammonolysis.
reaction,
requires
is the
led
(Figure
active
the
oxygen
which
this
water
for
dominant
be supplied
case
oxidative
was
be explained
as much
by nitrogen
of 3-ethylpyridine due
the can
reaction
In our
V205
co-existing
and,
without
considerably
ammonolysis
result
the
that
con-
necess-
the
TPR
of the
indicate
to 3-cyanopyridine
of the
production
twice
oxygen
sumed
water
course
of 3-picoline,
This
of the
selectivity
conducted
no water
group
pyridine.
one
pyridine
oxidative
the
that
the
catalyst
when
significant
two
products. V 0 49
oxygen,
1) and
as measured
not
exhibited
oxides.
hydrogen amount
by the
(Table
weak-
in the
selectivity.
ammonolysis
nadium
was
bound
measurements
from
V,O,/V,O,
to 70%
tarry
phase
did
when
either
selectivity
of pyridine
activity
measured
the
to the
is indicated
samples
area
area
that
place
ammonolysis.
reduction
surface
corresponding
lower
examined
was
weakly
of the most
takes
exactly
results
different
the
to note
titrimetric
analysis
oxidative
ever,
as
Removal
9) already
of the
important
X-ray
with
during
reaction.
corresponded
depletion
to be
B. C. D and number,
9) obtained
and
oxygen
After
started
in the
A in Figure
It is interesting
bound
to V6013.
oxygen
involved
of profile
reaction.
the weakly
V205
bound
are
peak
of the
remove
strongly
species
(first
In the
of 3case
it is pre-
of 3-ethylpyridine
will
of 3-ethylpyridine
to
3-vinylpyridine. Our portant
experiments reduction
conditions active
(Table step
applied,
state
of the
the
1) indicate
for
oxidative
reduction
vanadium
that
reduction
ammonolysis.
of the
oxide.
the
V205
from
Regardless
always
led
V
5+
to V4'
of the
to V02-6
is the
im-
experimental
as the
final
in-
248 Ammoxidation The and
on vanadium
results
C (V40,)
into and
displayed
account V4OB
that
This
some
of the
displayed
V409
our
results
Lundin
haviour
can
be noted.
yield
kylpyridines
X-ray
analysis with
to have
a slightly VO2-B.
E underwent
the most listed
results
it appears used.
investigations
nothing
to the
ammoxidation
ted
that
V02-B
sample
indicated
the
amount
V02-B,
towards
changes 2. Only
V6013
probably
V6013
of Andersson
more and
oxidation be concluded
experiments. is inactive
exhibited the
bea ma-
maximum
temperature, of our
grain
V205
at can
morphology
ammoxidation
on of al-
find
significant
be mentioned
of V60,3q formed
which
was
changes that
were
not
apparently
the de-
too
small
prevailing, Sample
exhibited
E containing
as sample
D. how-
at 365'C.
Sample
the
was
ammoxidation
detected and
its
intrinsic experiment
is apparent analysis
stable
would
Indication
( sample
as
by X-ray
relatively
V02-B
the
phase
at 365'C.
have
for
E) under activity presented
phase
from
after
use.
under
the
to be used
this
the and
emerges
to perfrom
conditions selctivity
in Figure
are due
to
LONZA
from
6 indica-
ammonolysis.
for
financially
supporting
this
the
used,
ACKNOWLEDGEMENT Thanks
be
(35%)
of the
Switzerland
by An-
selectivity
active
[Zl].
AG.
reported
similarly
Lundin
oxidative
not
latter
temperatures
for
in which dominant,
3-cyanopyridine
selectively.
about
V205)
(A) pha-
became
V205,
for
it should
or V409
active
However,
of the
we did
the
during
lower
V205
to both
laboratory.
traces
was
V6013
is a very
our lower
selectivity
of V6013
V205
selective
Taking
for
and yields.
with
than
V205
catalysts
in our
[21],
on conversion
for
influence
Although,
analysis,
drastic
with
can
use.
by X-ray
However,
decisive
our
Lundin
and
in Table
rapid
and
and
that
at a much
pentoxide
after
selectivity
that
ammoxidation
Owing
V409
less
The
those
activity
found
and
V205)
phase.
whereas,
activity
investigated
However, effect
lower
the
V205
they
phase
2) with
in the
appeared
morphology.
being
used
as detected
and
of vanadium
Andersson
sample.
considerably
conditions
grain
D containing
only
form
higher
of their
our
only
Thus,
the
of the
a significant
Sample
ever,
with
properties
tected
that
selectivity
(Figure
at 458'C,
60%
is presently
In agreement of the
of 34% was
to a different and
V205
B (V409,
latter
pure
analysis
selectivity
sample
the
as the
difference
yield
We believe
activity
with
that
B (V408,
at 365'c.
by X-ray
a similar
that
investigation,
of 3-cyanopyridine
37O'C.
ascribed the
In their
fact
such
selectivity
a striking
A (V205),
to 3-cyanopyridine
ascribe
by the
to V205, and
of reduction
samples
be detected
we may
obtained
[21].
3-cyanopyridine
about
could
2).
activity
and
of the
(Table
degrees that
selectivity
changes
converted
dersson
ximum
10 show
substantiated
was
a similar
Comparing
a similar
use
is further
of different
in Figure
no phase
(C) after
ses.
oxides
presented
work.
243
+ "409
-
800
700
V40g + V02-B
1000
900
TEMPERATURE(K> FIGURE
9
have
been
line
shown
Reduction
profiles
on
for
stream
in Figure
(TPR)
different
6. TPR
measured times
conditions:
for
vanadium
pentoxide
during
the
oxidative
sample
weig'ht. 75 mg:
samples
ammonolysis heating
which
of 3-picorate,
10 Umin.
Note
the
different
ammonolysis
specific
oxide
of the
In Figure
areas
shown
surface
of 3-picoline
on vanadium
which
samples
(Table
6. Ammoxidation
samples
C
B
A
of 3-picoline
123456
123456
123456
nn been
2).
see
reduced conditions
have
D
123456
.
I,L
.
1, CONVERSION, 2, 3-CYANOPYRIDINE, 3, PYRIDINE, 4. CARBONDIOXIDE,5, CARBONMON102 IE,6. TAR
I
I
Ammoxidation
oxidative
365'C.
the
FIGURE IO
100
during temperature
degrees 2: reaction
to different Figure
E
123456
hl
249
REFERENCES H. Kating, Pharm. Ztg., 23 (1968) 810. Brit. Pat. 1973. 1317064. A. Andersson. J. Catal., 69 (1981) 465. K. Watanabe, Bull. Chem. Sot. Japan, 37 (1964) 1325. Ger. Pat. 1975, 2517053. B.V. Suvorov, A.O. Kagarlitskii. N.V. Suslova and Y.G. 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 :a 25 ;;
Efremov,
Prikl.
Khim.,
45 (1972) 2588. Ger. Pat. 1975. 2435134. Ger. Pat. 1972. 1940320. H. Beschke. H. Friedrich. H. Schaefer and G. Schreyer, Chem. Ztg., 101 (1977) 384. B.V. Suvorov, A.O. Kagarlitskii, G.K. Kryukov. E.M. Guseinov and N.R. Bukeihanov, Kinet. Katal.. 15 (1974) 1507. B.V. Suvorov, A.O. Kagarlitskii, O.K. Sembaev and A.I. Loiko. Kinet.Katal., 19 (1978) 197. B.V. Suvorov, V.A. Yakovlev. A.O. Kagarlitskii. E.M. Guseinov. R.T. Kutzhanov, 1.1. Kan and O.B. Lebedeva. Khim Farm. Zh.. 10 (1976) 83. B.V. Suvorov. A-0. Kagarlitskii, 1.1. Kan and R.T. Kutzhanov. Kinet. Katal.. 18 (1977) 957. R. Prasad and A.K. Kar. Ind. Eng. Chem. Proc. Des. Oev.. 15 (1976) 170. A. Oas and A.K. Kar. Ind. Eng. Chem. Proc. Des. Oev.. 19 (1980) 689. S. Kumar and S.Z. Hussain, Chem. Eng. Sci., 35 (1980) 1425. R. Prasad and A.K. Kar. Indian J. Technol.. 15 (1977) 288. A. Andersson and S.T. Lundin, J. Catal., 65 (1980) 9. S.L.T. Andersson and S.J. Jarbs. J. Catal., 64 (1980) 51. S.L.T. Andersson. J.C.S. Faraday Trans.1.. 75 (1979) 1356. A. Andersson and S.T. Lundin. J. Catal.. 58 (1979) 383. M.C. Sze and A. P. Gelbein. Hydrocarbon Process., 55(1976) 103. J. Zi6lkowski and J. Janas. J. Catal.. 81 (1983) 298. ASTM Powder Diffraction File, 9-387, Ed. Joint Commitee on Powder Diffraction Standards, Pennsylvania, 1980. 0. M. Monti and A. Baiker. J. Catal.. 83 (1983) 323. M. Nakamura. K. Kawai and.Y. Fujiwara. J.‘Cataj.. 34 (1974) 345. O.R. Stull. E.F. Westrum and G.C. Sinke. The Chemical Thermodynamics of Drganic Compounds, Wiley, New York, 1969. S.W. Benson, Thermochemical Kinetics, Wiley, New York, 1976. P. Zollinger, Ph.D.-Thesis, ETH-Zurich. 1982. L. Fiersman. P. Clauws and W. Oekeyser. Can. Mineral. 16 (1978) 353. Reference [24], File 23-720. T. Sata and Y. Ito. Bull. Tokyo Inst. Techn.. 98 (1970) 1. F. Roozeboom. M.C. Mittelmeijer-Hazeleger, J.A. Moulin. J. Medema. V.H.J. de Beer and P.J. Gellings, J. Phys. Chem., 84 (1980) 2783. Reference [24]. File 27-1318. W.C. Cameron, A. Farkas and L.M. Litz, J. Phys. Chem. 57 (1953) 229.