Low-pressure one-step synthesis of methyl isobutyl ketone from acetone and hydrogen over metal modified solid base catalysts

Article abstract of DOI:10.1002/jccs.200200132

One-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen over metal modified solid base catalysts has been studied at atmospheric pressure and 175-250 °C by using a fixed-bed, integral-flow reactor. Two types of catalysts have been utilized: (1) zeolites modified with palladium (Pd/Kβ, Pd/KZSM-5); and (2) metal oxides modified with sodium and palladium (Pd/Na/MgO, Pd/Na/NaOH/γ-Al₂O₃). The catalyst properties were characterized by the methods of atomic absorption, temperature-programmed desorption and gas adsorption. Sodium vapor deposition on magnesia, followed by impregnation with tetraamine palladium (II) chloride apparently enhances the catalyst basicity as compared with that of magnesia supported palladium. For catalysts with different supports, the base amount decreases in the order of Pd/Na/MgO > Pd/Na/NaOH/γ-Al₂O ₃ > Pd/KZSM-5 > Pd/Kβ, in accordance with the catalytic activities. As the amount of sodium or palladium in Pd/Na/MgO increases, the catalyst base amount, acetone conversion and MIBK selectivity are also enhanced to a maximum and then decline. Better catalytic results were attained at a higher pretreating temperature of hydrogen on the catalyst. The optimum conditions for this reaction are 0.5%Pd/0.47%Na/MgO pretreated with hydrogen at 400 °C, reaction temperature 200 °C, acetone/hydrogen mol ratio 1, and W/F_a 6g·h/mol. Under these conditions, the acetone conversion and MIBK yield are 47.3% and 30.7%, respectively, at 480 min time-on-stream. The reaction network and reaction mechanism for the formation of MIBK are proposed and discussed.

Full text of DOI:10.1002/jccs.200200132

Journal of the Chinese Chemical Society, 2002, 49, 935-942
935
Low-Pressure One-Step Synthesis of Methyl Isobutyl Ketone from
Acetone and Hydrogen over Metal Modified Solid Base Catalysts
Kai-Hsun Lin (
) and An-Nan Ko* (
)
Department of Chemistry, Tunghai University, Taichung 407, Taiwan, R.O.C.
One-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen over metal modified
solid base catalysts has been studied at atmospheric pressure and 175-250 C by using a fixed-bed, int e -
gral-flow reactor. Two types of catalysts have been utilized: (1) zeolites modified with palladium (Pd/K ,
Pd/KZSM-5); and (2) metal oxides modified with sodium and palladium (Pd/Na/MgO, Pd/Na/NaOH/
-
2 3
Al O ). The cata l y s t properties were characterized by the methods of atomic absorption, temp e rature-
programmed desorption and gas adsorption. Sodium vapor deposition on magnesia, followed by impregna-
tion with tetraamine palladium (II) chloride apparently enhances the catalyst basicity as compared with that of
magnesia supported palladium. For catalysts with different supports, the base amount dec reases in the ord e r of
2 3
Pd/Na/MgO > Pd/Na/NaOH/ -Al O > Pd/KZSM-5 > Pd/K , in accordance with the catalytic activities. As
the amount of sodium or palladium in Pd/Na/MgO increases, the catalyst base amount, acetone conversion
and MIBK selectivity are also enhanced to a maximum and then decline. Better catalytic results were attained
at a higher pretreating temperature of hydrogen on the catalyst. The optimum conditions for this reaction are
0
.5%Pd/0.47%Na/MgO pretreated with hydrogen at 400 C, reaction temperature 200 C, acetone/hydrogen
mol ratio 1, and W/F 6g h/mol. Und e r these conditions, the acetone conversion and MIBK yield are 47.3%
a
and 30.7%, respectively, at 480 min time-on-stream. The reaction network and reaction mecha nism for the
formation of MIBK are proposed and discussed.
1
7
18
19
20
INTRODUCTION
The study of bifunctional catalysis has drawn much at-
Co, and Fe, Cu-on-MgO, Cu-MgO, and Ni-CaO.
For the synthesis of MIBK over niobia on silica, high
selectivities of 88-92% MIBK were observed at 30-35% con-
1
0
tention due to its great potential for process design and prod-
version. With palladium (0.05 < Pd < 0.5 wt.-%) supported
on Mg(Al)O mixed oxides, the highest MIBK selectivity was
attained with ca. 0.2 wt.-% Pd and size of Pd particles of ca.
1
uct development. The conventional process generally suf-
fers many disadvantages such as the complicated operation
system, the separation problem with reaction intermediates,
and the uncompetitive economical situation. The typical ex-
1
1
3-5 nm. For the reaction over Pd/ZSM-5, organic acid treat-
ment enhanced MIBK selectivity and catalyst life due to an
2
,3
12
amples include the reforming of naphtha hydrocarbons,
expansion of secondary pores and an increased acidi t y.
4
hydroprocessing of heavy fossil fuels, and the synthesis of
Pt/H[Al]ZSM-5 and Pt/H[Ga]ZSM-5 were utilized as cata -
lysts for acetone transformation to MIBK at 160 C and atm o -
spheric pressure. The results showed that metallic centers in
the Pt/H[Ga]ZSM-5 catalyst exhibited a much lower hy-
dro-dehydrogenating activity than those of the metallic cen-
5
6
2
-ethylhexanal and methyl isobutyl ketone. The traditional
method of manufacturing MIBK consists of three-step rea c -
tions: base-catalyzed aldol condensation of acetone in the liq-
uid phase to diacetone alcohol (DAA); acid catalyzed deh y -
dration of DAA to mesityl oxide (MSO); and metal catalyzed
1
3
ters in the Pt/H[Al]ZSM-5 catalyst. In the reaction over
AlPO -11 and SAPO-11, bas i c sites enhanced the catalytic
7
hydrogenation of MSO to MIBK. Recently, one-step pro-
4
cesses have been developed utilizing bifunctional catalysts
such as palladium or platinum metal supported on cation ex-
activity whereas Pd loading by ion-exchange, occlusion in
the pores or acid treatment of the support improved the MIBK
6
,8
7
16
change resins, zirconium phosphate, metal or mixed metal
oxides (Nb , KOH/Al , MgO/SiO , Nb /SiO and
and zeolites or molecular sieves (ZSM-5,
H[Al]ZSM-5, H[Ga]ZSM-5, (Zn)H-ZSM-5, H[B]ZSM-5,
selectivity. With layered double hydroxides containing Ni,
2
O
5
2
O
3
2
2
O
5
2
Co and Fe, the product selectivities depended strongly on the
components of catalysts; NiMgAl, CoMgAl and FeMgAl
produced MIBK, methyl isobutyl carbinol, and mesityl ox-
6
,9-11
Mg(Al)O),
1
2-16
17
AlPO
4
-11 and SAPO-11),
hydrotalcites containing Ni,
ide, respectively. A 3.46% Cu-on-MgO catalyst was pre-
Dedicated to the celebration of the seventieth anniversary of Chemical Society the located in Taipei.

9
36 J. Chin. Chem. Soc., Vol. 49, No. 5, 2002
Lin and Ko
pared by coprecipitation. Under the best conditions, MIBK is
finally to 550 C for 2 h. The palladium containing Na/MgO
catalyst (Pd/Na/MgO) was prepared by a similar method as
that of Pd/KZSM-5 or Pd/K . The symbol xPd/yNa/solid
base denotes x%Pd and y%Na loadi n g on the solid base.
1
8
formed in 45-48% yield.
In a previous paper, we reported the preliminary results
on highly selective synthesis of MIBK from acetone and hy-
2
1
drogen using magnesia supported palladium catalysts. In
this study, other bifunctional catalysts were also prepared
Catalyst Characterization
such as Pd/K , Pd/KZSM-5, and Pd/Na/NaOH/ -Al
2
O
3
. The
The BET surface area of catalysts was measured with a
gas sorption analyzer (Quantachrome Quantasorb). The so-
dium content in the Na/MgO sample was determined by dis-
solving 0.050 g Na/MgO in 20 mL of 1 M HCl solution fol-
lowed by analysis with atomic absorption spectrometry. The
catalyst basicity was obtained by temperature-programmed
catalyst properties were characterized and correlated to the
catalytic results. The effects of reaction parameters, viz. rea c -
tion temperature, time-on-stream, acetone/hydrogen mol ra-
tio, contact time and the pretreated temperature of hydrogen
were investigated so as to obtain the optimum reaction cond i -
tions. Furthermore, the reaction network and the reaction
mechanism for the formation of MIBK are proposed.
5
desorption of carbon dioxide. Before adsorption, 0.1 g of
catalyst sample was heated under helium flow (40 mL/min)
with a rate of 10 C/min from 110 to 500 C to remove water
from the sample and then cooled to room temperature. Mea-
sured pulses of carbon dioxide gas (pulse volume, 0.5 mL
NTP) were injected into helium gas and carried through the
sample till adsorption saturated. Then the temperature was
increased to 110 C and it was kept there for 2 h to remove the
physisorbed carbon dioxide. Finally, the system was heated
from 110 to 600 C at 10 C per minute and kept at 600 C for
30 min. The TPD diagrams were obtained by monitoring the
desorbed gas with a thermal conductivity detector. The cata -
lyst base amount was determined by comparing the peak area
EXPERIMENTAL SECTION
Catalyst Preparation
To prepare KZSM-5 zeolite, HZSM-5 (P.Q. Corp.,
2 2 3
SiO /Al O = 51) was heated at a rate of 6 C/min to 400 C
and calcined there for 24 h. After cooling to room tempera-
ture in a desiccator, the sample was ionic exchanged with a
KCl solution at 60 C with stirring for 5 h. After repeated
ionic exchange for one more time, the sample was heated at
1
10 C for 12 h and then calcined at 500 C for 4 h. K was
prepared in a similar way from H (P.Q. Corp., SiO /Al
5) and KCl solution. An adequate amount of tetraammine-
2
with that of a given amount of CO as the standard.
2
2 3
O =
2
Catalytic Reaction
palladium (II) chloride monohydrate was dissolved in de-
ionized water into which was added KZSM-5 or K with stir-
ring. The resulting mixture was heated at 110 C for 12 h and
then calcined at 500 C for 4 h to produce Pd/KZSM-5 or
Pd/K .
The reaction was performed at 1 atm and 175-250 C in
a fixed-bed, integral-flow reactor (1.7 cm I.D. 50 cm). Prior
to the reaction, the catalyst was treated with flowi n g hydro-
gen gas (50 mL/min) of high purity (99.99%) at 400 C for 10
h and then cooled to the reaction temperature with flowi n g ni-
2
2
To prepare Na/NaOH/ -Al
was calcined at 500 C for 12 h. Then 4.5 g NaOH (R.D.H.)
was added into-Al with stirring at 320 C for 3 h under
flowing N gas. Finally 1.2 g sodium metal was added into the
2 3 2 3
O , 30 g -Al O (Strem)
2
O
3
2
above mixture with stirring at 320 C for 1 h und e r an inert at-
mosphere of nitrogen. Such a catalyst was reported to exhibit
the diffraction peaks due to - alumina as well as sodium
2
2
aluminate according to X-ray analysis. Then 5 g of
Na/NaOH/ -Al was added into a 10 mL solution contain-
2
O
3
ing 0.062 g palladium tetraamine chloride monohydrate, fol-
lowed by dryi n g and then heated at 110 for 12 h, and finally
2 3
calcined at 500 C for 4 h to obtain 5%Pd/Na/NaOH/ -Al O
catalysts. Na/MgO was prepared as follows: 0.5 g sodium
metal and 5 g of MgO were put in a pyrex app a r a t u s under
flowing nitrogen as shown in Fig. 1. The system was pumped
Fig. 1. The apparatus for loading sodium on magnesia.
-
3
to a pressure of 10 torr, then heated to 480 C for 0.5 h and

Direct Synthesis of MIBK
J. Chin. Chem. Soc., Vol. 49, No. 5, 2002 937
trogen gas. Reagent grade acetone and hydrogen with a molar
ratio (A/H) of 0.25~4.0 were fed into the reactor at different
flow rates via a microfeeder (Razel A-99) and a gas flow con-
Table 1. The Catalyst Properties
Catalyst
Surface area
Base amount
2
(m /g)
(mmol CO /g)
2
a
troller (Scott 52-36E), respectively. The symbol W/F de-
0
0
.5Pd/K
.5Pd/KZSM-5
459
336
17
49
40
49
60
65
51
14
46
44
38
0.038
0.058
0.084
0.062
0.081
0.135
0.150
0.130
0.120
0.110
0.150
0.145
0.090
notes the weight of catalyst (g) divided by the feed rate of ac-
etone (mol/h). The reaction products were identified with a
GC-MS (Hitachi M-52) and periodically analyzed by a gas
chromatograph (HP 5890 series II) equipped with a PONA
column (0.2 mm 50 m) and a flame-ionization detector.
0.5Pd/Na/NaOH/ -Al O
2
3
0
0
0
0
0
0
.5Pd/MgO
.5Pd/0.12Na/MgO
.5Pd/0.29Na/MgO
.5Pd/0.47Na/MgO
.5Pd/0.64Na/MgO
.5Pd/0.7Na/MgO
RESULTS AND DISCUSSION
0.5Pd/2Na/MgO
0.2Pd/0.47Na/MgO
1Pd/0.47Na/MgO
5Pd/0.47Na/MgO
The Catalyst Properties
Fig. 2 shows the temperature-programmed desorption
profiles of carbon dioxide from various catalyst samples. For
the catalysts of different solid bases as supports, both the base
amount and the basic strength follow the decreasing ord e r of
basic sites, viz. oxy g e n anions in the MgO structure. Cons e -
quently, its vapor deposition on the MgO catalyst enhances
markedly the cata l y s t basicity. However, the deposition of
even a larger amount of sodium may block the catalyst base
sites and thus decrease the basicity. For xPd/0.47Na/MgO
catalysts, the base amount diminishes with the loading
amount of Pd, possibly due to its gradual coverage on the
base sites. Tab l e 1 indicates the BET surface area and base
amount of various catalysts. As is expected, 0.5Pd/K and
0
0
.5Pd/ Na/NaOH/ -Al
2 3
O > 0.5Pd/MgO > 0.5Pd/KZSM-5 >
.5Pd/K . With 0.5Pd/yNa/MgO catalysts, increasing the so-
dium content up to 0.47% results in the largest base amount
and basic strength. Further increase of sodium loadi n g causes
a decrease of catalyst basicity. These results are interpreted as
follows: the sodium metal exhibits strong electron donating
property and thus increases the electron density of catalyst
0
.5Pd/KZSM-5 reveal much larger surface area than other
catalysts which is attributed to the apparent difference in the
surface area of solid supports: K > KZSM-5 > MgO >
2
3-26
2 3
Na/NaOH/ -Al O .
The Catalytic Reaction
A i
The conversion of acetone (X ), the selectivity (S ) and
the yield (Yi) of ith product are defined on the bas i s of con-
verted acetone. For this reaction over Pd/Na/NaOH/ -Al
2 3
O ,
mol of acetone in the product
1
A
X (mol %) =
100%
mol of acetone in the feed
mol of acetone converted to ith product
Si (mol %) =
100%
mol of acetone converted
A
Yi (mol %) = X ×Si
Pd/MgO and Pd/Na/MgO, the main products are methyl
isobutyl ketone (MIBK) and diisobutyl ketone (DIBK). The
minor products include 2-propanol (2P), 4-methyl-2-pentanol
(
4M2P), 2,6-dimethyl-2-heptanone (DMH), and 2,6,8-tri-
Fig. 2. Temperature-programmed desorption of car-
bon dioxide profiles from various catalysts.
methyl-4-nonanone (TMN). Contrary to this result, a large

9
38 J. Chin. Chem. Soc., Vol. 49, No. 5, 2002
Lin and Ko
quantity of 2 P was produced in the reaction of acetone and
their variation with Pd content also infers that the catalytic re-
sults are consistent with the catalyst base amount.
2
7
hydrogen over the Ni/MgO catalyst. It is noteworthy that
the major product of propane instead of MIBK was observed
in the reaction over Pd/K and Pd/ KZSM-5, implying that
the nature of solid support influences remarkably the product
selectivities. Fig. 3 shows the relation between the MIBK
yield and the catalyst base amount. A nearly linear relation-
ship is observed. The MIBK yield decreases in the following
order: 0.5Pd/0.47Na/MgO > 0.5Pd/ MgO > 0.5Pd/Na/NaOH/
Fig. 6 shows the dependence of acetone conversion and
MIBK yield with acetone to hydrogen (A/H) mol ratio. The
best catalytic results are found at A/H mol ratio of 1. If either
acetone or hydrogen is in large excess, both the acetone con-
-
Al
similar base amount, viz. 0.5Pd/MgO and 0.5Pd/KZSM-5,
.5Pd/MgO gives the better yield in spite of its much smaller
2 3
O > 0.5Pd/KZSM-5 > 0.5Pd/K . For catalysts with a
0
surface area. Accordingly, both the basicity and the nature of
solid support instead of the surface area are essential for the
formation of MIBK.
As Pd/Na/MgO exhibits better catalytic results, the ef-
fects of Pd and Na loading (x & y) as well as reaction cond i -
tions are further investigated so as to obtain the optimum con-
ditions for the production of MIBK. Fig. 4 shows the influence
of sodium content in 0.5Pd/yNa/MgO on the catalyst base
amount, the acetone conversion and the MIBK yield. As the
amount of sodium increases up to 0.47%, all these three quan-
tities also enhance and reach maximum values, respectively.
Then they decline with further loading of sodium from 0.47 to
2
.0%. These results imply that the catalytic activity and MIBK
Fig. 4. Effects of sodium content in 0.5Pd/yNa/MgO
on cata l y s t base amounts and catalytic re-
sults. Reaction conditions the same as those
in Fig. 3. ( ) base amount; (¡) the conver-
sion; (l) MIBK yield.
yield correlates well with the catalyst base amount. Fig. 5
shows the effect of Pd loading in xPd/0.47Na/ MgO on the cat-
alytic results. The great similarity among the three curves in
Fig. 3. Dependence of MIBK yield on the catalyst
base amount. Reaction conditions: 1 atm; 200
Fig. 5. Effects of palladium content in xPd/0.47Na/
MgO on catalyst base amounts and catalytic
results. Reaction conditions the same as those
in Fig. 3. ( ) base amount; (¡) the conver-
sion; (l) MIBK yield.
C; A/H, 1; W/F
¡) 0.5Pd/K ; (l) 0.5Pd/KZSM-5; (+)
.5Pd/Na/NaOH/ -Al ; ( ) 0.5Pd/MgO;
5) 0.5Pd/0.47Na/MgO.
a
6 g h/mol; T.O.S., 360 min.
(
0
2 3
O
(

Direct Synthesis of MIBK
J. Chin. Chem. Soc., Vol. 49, No. 5, 2002 939
version and MIBK yield become markedly smaller. Such a
result demonstrates that similar amounts of acetone and hy-
drogen adsorbed, respectively, on the basic sites and the Pd
sites lead to high acetone conversion and MIBK yield. Cons e -
quently, the best catalytic results occ u r at a A/H mol ratio of
crease with the pretreated temperature. Therefore, favorable
formation of MIBK other than 2P occurs at high pretreated
temperature, which is in accordance with the literature re-
2
8
port. Fig. 8 shows the influence of reaction temperature and
time-on-stream on the catalytic activity. The initial activity
increases with the reaction temperature. Furthermore, the
catalyst decay rate also follows a similar trend. Accordingly,
the conversions at 480 min time-on-stream decrease in the or-
der of 175 C 200 C > 225 C > 250 C. Fig. 9 shows the re-
lations between the catalytic results and the base amount of
1
. Fig. 7 shows the effect of hydrogen pretreated temperature
on the catalytic results. The conversion enhances with the
pretreated temperature from 200 to 400 C and then declines
at 500 C; the 2P selectivity reveals an opposite trend,
whereas the MIBK selectivity exhibits a slight but steady in-
60
80
70
50
60
40
50
40
30
30
20
20
10
10
0
1
2
3
4
0
100
200
300
400
500
A/H(mol ratio)
Time-on-stream(min)
Fig. 6. Relations of catalytic results over 0.5Pd/
.47Na/MgO with A/H mol ratio. Reaction
Fig. 8. Catalytic activities over 0.5Pd/0.47Na/MgO
as a function of reaction temperature and
time-on-stream. Reaction conditions: 1 atm;
0
conditions the same as those in Fig. 3. (¡)
the conversion; (l) MIBK yield.
A/H 1; W/F
a
, 6g h/mol. ( )175 C; (¡) 200
C; (5) 225 C; (n) 250 C.
70
70
60
60
50
50
40
40
30
30
20
20
10
10
0
0
200
300
400
500
0.06
0.08
0.10
0.12
0.14
0.16
H (Temperature)
Base amount (mmol CO
2
/g.cat.)
2
Fig. 7. Relations of catalytic results with pretreated
temperature of hydrogen on 0.5Pd/0.47Na/
MgO. Reaction conditions the same as those
in Fig. 3. (¡) the conversion; (l) MIBK se-
lectivity; (5) 2P selectivity.
Fig. 9. Dependence of catalytic results over Pd/Na/
MgO catalysts on the catalyst base amount.
Reaction conditions the same as those in Fig.
3. (¡) the conversion; (l) MIBK yield; (n)
DIBK yield.

9
40 J. Chin. Chem. Soc., Vol. 49, No. 5, 2002
Lin and Ko
Pd/Na/MgO catalysts. Apparently, the conversion, MIBK
and DIBK yield are parallel to the base amount. Fig. 10 shows
the conversion, MIBK and DIBK selectivity as a function of
results inf e r the production of DIBK from MIBK. The cata -
lytic results are summarized in Table 2. The optimum cond i -
tions for this reaction are as follows: 0.5Pd/0.47 Na/MgO
pretreated with hydrogen at 400 C, reaction temperature 200
a
contact time (W/F ). As the contact time increases, the con-
version also enhances whereas the MIBK selectivity decrease
with concomitant increases of the DIBK selectivity. These
a
C, A/H mol ratio 1, and W/F 6 g h/mol.
Fig. 11 illustrates the proposed reaction network and the
reaction mecha n i s m for the formation of MIBK. The main path
(
I) consists of self condensation of ace t o n e on the catalyst ba-
sic sites to produce diacetone alcohol (DAA) (step I ) followed
by dehydration to mesityl oxide (MSO) (step I ). Selective hy-
drogenation of MSO on the metallic sites yields MIBK (step
). In a similar way, DIBK is produced from MIBK, acetone
and hydrogen (step I ). The less important paths (II & III) cor-
100
1
8
0
0
0
0
2
6
4
2
I
3
4
respond to the direct hydrogenation on the carbonyl functional
group of acetone and MIBK to yield the minor products of 2P
and 4M2P, respectively. The absence of all hydrogenated prod-
ucts over MgO and Na/MgO catalysts shows the function of
palladium as metallic sites for hydrogenation. As the MIBK
and DIBK selectivities are much higher than those of 2P and
0
0
5
10
15
20
W/Fa (g·h/mol)
4
M2P, this implies hydrogenation of the C C bond of a ketone
being much faster than hydrogenation of the carbonyl group.
Such selective hydrogenation over palladium catalyst gene r -
Fig. 10. Effects of contact time on catalytic results
over 0.5Pd/0.47Na/MgO catalyst. Reaction
conditions the same as those in Fig. 3. (¡)
the conversion; (l) MIBK selectivity; (n)
DIBK selectivity.
2
9,30
ally applies to unsaturated ketone and aldehydes.
Further-
more, DAA and MSO were not detected in the product mix-
ture; this shows that steps I
2
and I
3
are much faster than steps I
1
DAA
MSO
MIBK
DIBK
I1
I2
I3
I4
2
Me CO
Me C(OH)CH COMe
Me CCHCOMe
Me CHCH COMe
(Me CHCH ) CO
2 2 2
2
2
2
2
2
2
-
H O
+H2
2
II
III
Me CH(OH)
Me CHCH CH(OH)Me
2
2
2
2P
4M2P
DAA
MSO
MIBK
Me C CH COMe
2
2
Me C
CHCOMe
H O
2
Me C
CH COMe
2
2
-
+H2
Me CHCH COMe
O
H
2
2
2
Me C CHCOMe
2
O
H
HO
H
2Had
H2
Pd
A
B
A
A
A
B
B
B
A : Acid site
B : Basic site
Fig. 11. The proposed reaction network and reaction mechanism for the formation of MIBK.

Direct Synthesis of MIBK
J. Chin. Chem. Soc., Vol. 49, No. 5, 2002 941
Table 2. The Catalytic Results. Reaction Conditions: 1 atm; 200 C; W/F , 6 g h /mol; A/H, 1; T.O.S., 360 min
a
a
Catalyst
Conversion
Selectivity (mol %)
(mol %)
2P
MIBK
4M2P
DIBK
DMH
TMN
b
0
0
0
0
0
0
0
0
0
0
0
1
5
.5Pd/K
.5Pd/KZSM-5
29.72
32.87
12.80
24.68
34.09
51.32
54.19
50.42
49.96
43.01
50.96
39.92
26.18
5.11
12.98
8.37
12.23
4.45
3.92
1.68
4.07
11.73
2.03
10.53
18.34
72.47
67.20
69.80
58.71
59.69
58.92
58.69
68.87
61.98
65.26
65.28
0
0
0
4.50
2.81
0
0
0.83
6.71
4.09
2.55
3.84
7.24
7.71
8.15
0.82
4.27
6.68
5.34
2.21
b
.5Pd/Na/NaOH/ -Al O
.5Pd/MgO
12.67
14.21
17.12
25.31
26.45
23.91
22.55
20.02
23.88
17.72
11.49
2.40
2.57
3.53
3.87
4.03
3.86
3.43
4.38
3.94
3.43
2.31
2
3
1.24
1.26
0.95
0.44
1.09
2.78
0.43
0.69
1.17
1.71
.5Pd/0.12Na/MgO
.5Pd/0.29Na/MgO
.5Pd/0.47Na/MgO
.5Pd/0.64Na/MgO
.5Pd/0.7Na/MgO
.5Pd/2Na/MgO
.2Pd/0.47Na/MgO
Pd/0.47Na/MgO
Pd/0.47Na/MgO
2.83
7.08
17.00
a
2P, 2-propanol; MIBK, methyl isobutyl ketone; 4M2P, 4-methyl-2-pentanol; DIBK, diisobutyl ketone; DMH, 2,6-
dimethyl-2-heptanone; TMN, 2,4,8-trimethyl-4-nonanone.
Additional products of propane and 2-methyl pentane with selectivities 49.91% and 9.25%, respectively, for the
reaction over 0.5Pd/KZSM-5 and 69.64% and 9.39% over 0.5Pd/K .
b
and I
4
. The mecha n i s m of MIBK formation is explained as fol-
ACKNOWLEDGEMENT
lows: the C H of acetone is adsorbed on the basic sites. Self
condensation produces DAA followed by dehydration on acid
sites to yield MSO, which then reacts with the adsorbed H
atom on Pd metals to produce MIBK.
We thank the National Science Council of the Republic
of China for financial support.
Received July 9, 2002.
CONCLUSION
Key Words
In the direct synthesis of MIBK from acetone and hy-
drogen, the catalytic activity and product selectivity depend
on both the nature of catalysts and the reaction conditions. A
good catalyst should contain suitable amounts of base sites,
acid sites, and metallic palladium sites so as to exhibit the
bifunctional characteristics of aldol condensation, dehydra-
tion, and hydrogenation. The contents of sodium and pall a -
dium in the catalyst and the nature of solid base supports af-
fect considerably the catalyst basicity; 0.5Pd/0.47Na/MgO
was found to exhibit the largest bascity. The catalytic activity
correlates well with the catalyst base amount. As metal pall a -
dium catalyzes selective hydrogenation of C C instead of
C O double bond, it leads to the favorable formation of
MIBK other than alcohol products. The optimum conditions
for this reaction are as follows: 0.5Pd/0.47Na/MgO pre-
treated with hydrogen at 400 C, reaction temperature 200
Methyl isobutyl ketone; Bifunctional catalyst; Aldol
condensation; Hydrogenation; Magn e s i a supported
palladium.
REFERENCES
1
. Gate, B. C. Catalytic Chemistry, John Wiley & Sons, Inc.:
New York, 1992, chapter 6.
2. Van Santen, R. A.; Kuipers, H. P. C. E. Adv. Catal. 1987, 35,
265.
3. Ramage, M. P.; Graziani, K. R.; Schipper, P. H.; Krambeck,
F. J.; Choi, B. C. Adv. Chem. Eng. 1987, 13, 193.
. Quann, R. J.; Ware, R. A.; Hung, C.-W.; Wei, J. Adv. Chem.
Eng. 1988, 14, 95.
. Ko, A.-N.; Hu, C. H.; Chen, J.-y. Appl. Catal. A: General
4
5
6
7
1
999, 184, 211.
a
C, A/H mol ratio 1 and W/F 6 g h /mol. Und e r these cond i -
. Kirk-Othmer Encyclopedia of Chemi c a l Technology, Vol. 13,
John Wiley & Sons, Inc.: New York, 1979, p 907.
. Weissermel, K.; Apre, H.-J. Industrial Organic Chemistry.
tions, the conversion and MIBK yield are 47.3% and 30.7%,
respectively, at 480 min time-on-stream.

9
42 J. Chin. Chem. Soc., Vol. 49, No. 5, 2002
Lin and Ko
3
rd Ed., Lindley, C. R. (Translator), VCH: New York, 1997,
19. Varga, M.; Molnár, Á; Mulas, G.; Mohai, M.; Bertóti, I.;
Cocco, G. J. Catal. 2002, 206, 71.
p. 280-281.
8
. Zhao, W.; Fang, Y.; Zhang, S.; Zhang, W. Lizi Jiaohuan Yu
Xifu 1990, 6, 52.
20. Coh, B. Y.; Cho, K. H.; Lee, H. I. J. Chem. Eng. Jpn. 2001,
34, 138.
9
. Maki, T.; Yokoyama, T.; Sumino, Y.; Jpn Pat. 63 68 538
21. Lin, K.-H.; Ko, A.-N. Appl. Catal. A: General 1996, 147,
L259.
(
1988) to Mitsubishi Chemical Industries Co., Ltd.
1
1
1
1
1
1
0. Chen, Y. Z.; Liaw, B. J.; Tan H. R.; Shen, K. L. Appl. Catal.
A: General 2001, 205, 61.
1. Das, N.; Tichit, D.; Durand R.; Graffin P.; Coq, B. Catal.
Lett. 2001, 71, 181.
2. Chen, P. Y.; Chu, S. J.; Lin, W. C.; Wu, K. C.; Yang, C. L.
Stud. Surf. Sci. Catal. 1994, 83, 481.
3. Melo, L.; Llanos, A.; Mediavilla, M.; Moronta, D. J. Mol.
Catal. A: Chemi c a l 2002, 177, 281.
4. Bombos, D.; Bozga, G.; Bombos, M.; Stefan, A.; Stanciu, I.
Chemical papers- Chemicke Zvesti 2000, 54, 171.
5. Melo, L.; Giannetto, G.; Cardozo, L.; Llanos, A.; GarCia, L.;
Magnoux, P.; Guisnet, M.; Alvarez, F. Catal. Lett. 1999, 60,
22. Suzukamo, G.; Fukao, M.; Hibi, T.; Tanaka, K.; Chikaishi,
K. in Acid-Base Catalysis, Tanabe, K.; Hattori, H.;
Yamaguchi, T., Eds., Proceedings of the International Sym-
posium on Acid-Base Catalysis, Sapporo, Nov. 28-Dec. 1,
1988, Kodansha Ltd.: Tokyo, 1989, p 405.
23. Zhu, W.-D.; Ko, A.-N. J. Chin. Chem. Soc. 2000, 47, 1237.
24. Yu, J.-I.; Shiau, S. Y.; Ko, A.-N. Catal. Lett. 2001, 77, 165.
25. Ouyang, K.-H.; Chen, C.-W.; Ko, A.-N. J. Chin. Chem. Soc.
2001, 48, 137.
26. Chen, J.-Y.; Ko, A.-N. React. Kinet. Catal. Lett. 2000, 71,
77.
27. Gandia, L. M.; Montes, M. Appl. Catal. A: General 1993,
101, L1.
28. Watanabe, H.; Seto, J. Appl. Catal. A: General 1996, 134,
220.
29. Rylander, P. N. Hydrogenation Methods, Academic Press:
London, 1985, p 70.
30. Kizling, M. B.; Bigey, C.; Touroude, R. Appl. Catal. A: Gen-
eral 1996, 135, L13.
2
17.
6. Yang, S.-M.; Wu, Y. M. Appl. Catal. A: General 2000, 192,
11.
7. Unnikrishnan, R.; Narayanan, S. J. Mol. Catal. A: Chemi c a l
999, 144, 173.
8. Chikán, V.; Molnár, Á; Balázsik, K. J. Catal. 1999, 184,
34.
1
1
1
2
1
1