Rhodium Pyrrolylphosphine Complexes as Highly Active and Selective Catalysts for Propene Hydroformylation: The Effect of Water and Aldehyde on the Reaction Regioselectivity

Article abstract of DOI:10.1002/cctc.201700917

The hydroformylation of propene catalyzed by Rh(acac)(CO)₂ (acac=acetylacetonate) with a 13-fold excess of N-pyrrolylphosphine ligands PPyr₃, PPh₂Pyr, or PPh(Pyr)₂ (Pyr=NC₄H₄) was investigated under a pressure of 15 bar (propene/H₂/CO=5:5:5) at 80 °C. The N-pyrrolylphosphine ligands facilitated an excellent regioselectivity towards n-butanal aldehyde, significantly better than PPh₃ and PCy₃ under the same conditions. In the presence of the strongest π-acceptor, PPyr₃, the linear-to-branched aldehyde (l/b) ratio was 8.6, which increased to 27.1 if water was added to the system. The application of a pure aldehyde as a solvent instead of toluene caused a significant increase in the aldehyde yield but with a decreased l/b ratio (2.9–7.6). The regioselectivity parameter l/b increased to 19.3 after the introduction of water as a cosolvent.

Full text of DOI:10.1002/cctc.201700917

Accepted Article
Title: Pyrrolylphosphine-rhodium complexes as highly active and
selective catalysts for propene hydroformylation: The effect of
water and aldehyde on reaction regioselectivity
Authors: Ewa Mieczynska, Ryszard Grzybek, and Anna Trzeciak
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10.1002/cctc.201700917
Pyrrolylphosphine-rhodium complexes as highly active and selective catalysts for
propene hydroformylation: The effect of water and aldehyde on reaction regioselectivity
a
b
a*
E. Mieczyńska , R. Grzybek , A.M. Trzeciak
a
University of Wrocław, Faculty of Chemistry, 14 F. Joliot-Curie St., 50-383 Wrocław, Poland
Grupa Azoty, Zakłady Azotowe Kędzierzyn-Koźle S.A., Mostowa 30A, Kędzierzyn-Koźle, Poland
b
Abstract
The hydroformylation of propene catalyzed by Rh(acac)(CO) with a 13-fold excess of N-
2
pyrrolylphosphine ligands, L = PPyr , PPh Pyr or PPh(Pyr) , (Pyr = NC H ), was investigated under a
3
2
2
4
4
pressure of 15 bar (propene/H /CO = 5/5/5) at 80 °C. N-pyrrolylphosphine ligands facilitated excellent
2
regioselectivity towards n-butanal aldehyde, significantly better than PPh and PCy under the same
3
3
conditions. In the presence of the strongest -acceptor, pyrrolylphosphine (PPyr ), the l/b ratio
3
(
linear/branched aldehyde) was 8.6, and it increased to 27.1 when water was added to the system.
The application of a pure aldehyde as a solvent instead of toluene caused a significant increase in
aldehyde yield, but with a lowered l/b ratio (2.9–7.6). The regioselectivity parameter l/b increased to
19.3. after the introduction of water as a co-solvent.
key words: rhodium, hydroformylation, pyrrolylphosphine, propene, aldehyde
Introduction
Hydroformylation, the conversion of olefin, carbon monoxide, and dihydrogen to the corresponding
aldehyde, is one of the largest industrial processes with a capacity of over 9 million tons of the
products per year [1-7]. The selection of the catalytic system for hydroformylation is based primarily
on its high activity and regioselectivity, expressed by the l/b ratio (l = linear aldehyde, b = branched
aldehyde). Both the parameters are affected by the electronic and steric properties of the ligands
coordinated to the transition metal center. Therefore, extensive research has been devoted to the design
of new ligands enabling the selective production of linear aldehydes and then linear alcohols [1-7].
Theoretical studies on the effect of ligands on the hydroformylation reaction course have also made
important contributions to this field [8-13].
The most frequently used catalytic systems for hydroformylation contain Rh(I) precursors and
modifying phosphorus ligands used in excess relative to rhodium. Monodentate and bidentate ligands
have been applied in the hydroformylation of olefinic substrates, containing terminal or internal
double bonds and different substituents and functional groups. Experimental as well as theoretical
results indicate the advantages of π-acceptor ligands, which facilitate the formation of linear products
1
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ChemCatChem
10.1002/cctc.201700917
[
6, 11-14]. In this context, N-pyrrolylphosphines should be mentioned. They are strong π-acceptors,
stronger than phosphites (P(OR) ), and, advantageously, the P–N bond is more stable than P–O [15,
3
16].
Pyrrolylphosphines, PPh Pyr, PPh(Pyr) , PPyr (Pyr = NC H ), have been successfully applied in the
2
2
3
4
4
hydroformylation of terminal (1-hexene, ethene) [14, 17- 21] as well as internal olefins (2-pentene, 2-
hexene) [22]. Styrene, α–methylstyrene, and dicyclopentadiene have also been transformed into
aldehydes in rhodium systems containing pyrrolylphosphines [23–26]. For example, the conversion of
α–methylstyrene increased from 42.6% for PPh to 97.2% for P(Pyr) [25]. It should be underlined
3
3
that, in 1-hexene hydroformylation with different Rh(I) precursors and pyrrolylphosphines [17–21],
the yield of aldehydes and selectivity to n-heptanal have been significantly higher than with PPh [27–
3
2
9]. The best results in ethene hydroformylation have also been obtained for Rh(acac)(CO) /PPyr3
2
[
26]. A good regioselectivity and high activity has been achieved in rhodium catalyzed
hydroformylation of 1-octene with bidentate N-pyrrolyl phosphine [30].
Rhodium complexes with tripyrrolylphosphine, [RhClCOD(PPyr )], HRhCO(PPyr3)3] and
3
HRh(PPyr ) , have also been applied in the hydrogenation of organonitriles [31], cyclic olefins, and
3
4
aromatics [32].
In this paper we present the application of pyrrolylphosphines for the first time in the
hydroformylation of propene, a very important industrial process.
Results and discussion
In the hydroformylation of propene, two products were expected, a linear aldehyde (l), n-butanal, and
a branched aldehyde (b), 2-methylpropanal (Scheme 1). The proportion between them depends on the
reaction conditions and, in particular, on the kind of P-ligand which is coordinated to rhodium in the
active catalyst. Preferred are highly selective systems that produce a significant excess of the linear
aldehyde.
CHO
[
Rh]
CHO
+
+
CO + H2
l
b
Scheme 1.
First, a reference system, Rh(acac)(CO) /PPh , was studied. In propene hydroformylation performed at
2
3
o
8
0 C using a pressure of 15 bar (propene/H /CO = 1/1/1), the total amount of aldehydes after 150 min
2
was 0.0084 mol, and the l/b ratio was 2.3 (Table 1, entry 1). Only a slightly higher l/b value, 2.8, was
obtained after a shorter time (55 min) (Table 1, entry 2). A further increase in the l/b selectivity to 3
was achieved when the amount of toluene (solvent) was reduced from 2 ml to 1 ml (Table 1, entry 3).
2
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10.1002/cctc.201700917
However, under these conditions the amount of aldehydes also decreased. That negative effect was
compensated by the introduction of water to the reaction mixture (Table 1, entry 4 and 6).
Consequently, the best results were obtained for the reaction performed in a water/toluene system
(
1:1) (Table 1, entry 6). A similarly positive effect of water was also observed during 1-hexene
hydroformylation [33]. Here, water evidently enhanced the reaction rate, while regioselectivity
changed only slightly.
The change of the propene partial pressure to 3 bar showed that its influence on the reaction selectivity
was rather small. At 3 bar of propene, the l/b ratio was 3, similar to that obtained at a higher pressure,
5
bar (Table 1, entry 7).
Table 1. Propene hydroformylation in the Rh(acac)(CO) /PPh system
2
3
entry yield of
aldehydes
ald/Rh
TON)
conver- TOF
sion (%)
l/b time
(min)
solvent (ml)
-1
(
(min )
(
mol)
1
2
3
4
5
6
7
0.0084
0.004
560
267
300
366
233
286
204
88
66
73
88
74
90
60
3.73
4.85
7.5
2.3
2.8
2.8
2.7
3
150
55
toluene (2)
toluene (2)
0.0045
0.0055
0.0035
0.0043
0.0030
40
toluene (1.5)
9.15
5.83
7.15
1.36
40
toluene (1.5) + water (0.5)
toluene (1)
40
3.1
3
40
toluene (1) + water (1)
toluene (2)
*
150
-5
Reaction conditions: Rh(acac)(CO) (1.5∙ 10 mol), PPh /Rh =13), propene/H /CO = 5 bar/5 bar/5 bar
8
2
3
2
*
0º C, autoclave 100 ml. propene, 3 bar
Next, the influence of pyrrolylphosphine, PPh Pyr, was studied under the same conditions. The
2
application of PPh Pyr instead of PPh resulted in an increase in the reaction rate. It is illustrated by an
2
3
increase in the yield of aldehydes obtained after 150 min, from 0.0084 with PPh (Table 1, entry 1) to
3
0
.035 mol in the presence of PPh Pyr (Table 2, entry 1). The regioselectivity was also better, and the
2
l/b ratio was 4.2 after 150 min and 3.5 after 41 min (Table 2, entry 1 and 2). When a smaller volume of
toluene was used (1.5 ml or 1 ml), the l/b selectivity increased to 4.7–5 with some decrease in the
aldehyde yield, to 0.0056 and 0.0063 mol (Table 2, entry 3 and 5). The best regioselectivity was
achieved in that system after the addition of water, although it was accompanied by a slightly lower
yield than in toluene only. Thus, the l/b ratio increased from 4.7 to 5.6 for 0.5 ml of water and from
5
.0 to 7.9 for 1 ml of water (Table 2, entry 4 and 6).
3
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10.1002/cctc.201700917
Table 2. Propene hydroformylation in the Rh(acac)(CO) /PPh Pyr system
2
2
entry yield of
aldehydes
mol)
ald/Rh conver-
TOF
l/b
time
(min)
solvent (ml)
sion (%)
-1
TON
(min )
(
1
2
3
4
5
6
0.035
2310
480
373
347
422
226
93
83
84
85
79
76
15.4
11.7
9.3
4.2
3.5
4.7
5.6
5
150
41
40
40
40
40
toluene (2)
toluene (2)
toluene (1.5)
0.0072
0.0056
0.0052
0.0063
0.0034
8.7
toluene (1.5) + water (0.5)
toluene (1)
10.6
5.65
7.9
toluene (1) + water (1)
-5
Reaction conditions: Rh(acac)(CO) (1.5∙ 10 mol), PPh Pyr/Rh =13), propene/H /CO = 5 bar/5 bar/5
bar 80º C, autoclave 100 ml. propene, 3 bar
2
2
2
*
A further increase in selectivity was achieved when a less basic phosphine, PPh(Pyr) , was applied.
2
For example, after 40 min of propene hydroformylation with that phosphine, the l/b value was 10.5
(
Table 3, entry 4). Similarly as in the previously studied systems, in more concentrated solutions,
containing 1.5 or 1 ml of toluene, l/b was higher, 12.3 and 15 after 40 min of the reaction (Table 3,
entry 5 and 8). Unfortunately, a reduction of the solution volume caused a significant decrease in the
yield of aldehydes. In that system, the addition of water had practically no influence on the reaction
course, and, in particular, on hydroformylation selectivity (Table 3, entry 6 and 9).
Table 3. Propene hydroformylation in the Rh(acac)(CO) /PPh(Pyr) system
2
2
entry yield of
aldehydes
ald/Rh conver TOF
-sion
l/b
time
solvent (ml)
-1
TON
(min )
(min)
(
mol)
(%)
93
88
70
74
89
78
81
60
79
1
2
3
4
5
6
7
8
9
0.032
2093
994
397
333
276
297
300
200
207
14
4.6
150
60
43
40
43
40
60
40
40
toluene (2)
0.0149
0.0060
0.005
16.6
9.2
8.3
6.4
7.4
5
9.1
toluene (2)
10.3
10.5
12.3
12.2
13.9
15
toluene (2)
toluene (2)
0.0041
0.0045
0.0050
0.003
toluene (1.5)
toluene (1.5) + water (0.5)
toluene (1)
5
toluene (1)
0.0031
5.2
15.9
toluene (1) + water (1)
4
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10.1002/cctc.201700917
-5
Reaction conditions: Rh(acac)(CO) (1.5∙ 10 mol), PPh(Pyr) /Rh =13), propene/H /CO = 5 bar/5
2
2
2
bar/5 bar 80º C, autoclave 100 ml.
In propene hydroformylation performed in the presence of the most -acceptor pyrrolylphosphine,
PPyr , after 150 min, the yield of aldehydes was 0.028 mol with l/b = 8.6 (Table 4, entry 1). Even
3
higher l/b values, up to 20.8, were noted in that system in a shorter time (30–60 min) (Table 4, entry 8
and 2). The use of the amount of toluene reduced to 1.5–1 ml also had a positive influence on the l/b
ratio; however, it was accompanied by a decrease in aldehyde yield (Table 4, entry 4 and 6). The
increase in the l/b ratio can be attributed to the increased stability of the catalytically active form
responsible for the formation of n-butanal in a more concentrated solution. A significant improvement
in the productivity of that system was achieved in the presence of water. Water facilitated an increase
in both parameters, namely the yield of aldehydes and the selectivity to n-butanal. The highest l/b
values, 22.2 and 27.1, were reached in the presence of 0.5 and 1 ml of water (Table 4, entry 5 and 7).
It should also be noted that the reaction course was only slightly affected by the changes of propene
partial pressure. Thus, for 3 atm of propene, l/b after 150 min was 4.6 (Table 4, entry 9), while for 7
atm, it was 5.8 (Table 4, entry 10). Higher selectivity, l/b = 10.2 – 11.7, was achieved at 7 bar of
propene after shorter time, 25 – 35 min (Table 4, entry 11 and 12).
Table 4. Propene hydroformylation in the Rh(acac)(CO) /PPyr system
2
3
entry yield of
aldehydes
ald/Rh conver TOF
-sion
l/b
time
(min)
solvent (ml)
-1
TON
(min )
(
mol)
(%)
92
78
69
77
88
82
80
58
90
89
78
70
1
2
3
4
5
6
7
8
9
1
1
1
0.0282
0.01
1881
674
367
419
497
127
255
167
1290
1493
718
522
12.5
11.2
9.2
8.6
150
60
toluene (2)
14.3
16.2
17.2
22.2
18.2
27.1
20.8
4.6
toluene (2)
0.006
40
toluene (2)
0.0063
0.0075
0.0019
0.0038
0.0025
0.0194
0.0224
0.0108
0.0078
9.7
43
toluene (1.5)
toluene (1.5) + water (0.5)
toluene (1)
12.4
3.2
40
40
6.4
40
toluene (1) + water (1)
toluene (2)
5.6
30
*
*
*
*
8.6
150
150
35
toluene (2)
*
*
*
0
1
2
10
5.8
toluene (2)
20.5
20.9
10.2
11.7
toluene (2)
25
toluene (2)
5
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10.1002/cctc.201700917
-
5
Reaction conditions: Rh(acac)(CO) (1.5∙ 10 mol), PPyr /Rh =13), propene/H /CO = 5 bar/5 bar/5 bar
8
2
3
2
*
**
0º C, autoclave 100 ml. propene, 3 bar, propene 7 bar.
In all the studied reactions, selectivity to n-butanal decreased along with the lengthening of the time
and the amount of the branched aldehyde increased. In order to get a better understanding of the
observed trend, studies on the effect of the added aldehydes on the hydroformylation reaction course
were undertaken. For that purpose, the most selective system, Rh(acac)(CO) /PPyr , was selected.
2
3
Reactions were performed in pure aldehyde (n-propanal, n-butanal, 2-methylpropanal) and in mixed
solvent systems containing aldehyde/toluene or aldehyde/water. The most representative results are, in
our opinion, those obtained using n-propanal, which was not a reaction product (in contrast to n-
butanal or 2-methylpropanal), and, therefore, the estimation of the yield and selectivity was more
precise in that case.
The application of pure aldehyde (n-propanal) instead of toluene caused a significant increase in
aldehyde yield, but with a lowered l/b ratio. For example, a 45 min reaction in toluene produced
0
.0019 mol of aldehydes with the l/b ratio of 18.2 (Table 4, entry 6), whereas 0.0245 mol of aldehydes
with l/b = 7.6 were obtained in n-propanal (Table 5, entry 1). The difference between reactions in both
the solvents was also clearly seen after 2.5 h. Thus, the amount of aldehydes was 0.0448 mol and l/b
was 2.9 in n-propanal (Table 5, entry 2), whereas 0.028 mol of aldehydes was formed with
significantly higher l/b, 8.6, in toluene (Table 4 entry 9).
What is important, water modified the reaction course in the aldehyde medium in a positive way,
enabling an increase in selectivity to the linear aldehyde. After 45 min of the reaction in an n-
propanal/water mixture (1:1), the l/b value was 19.3 (Table 5, entry 6), decreasing to 11.0 after 2.5 h
(
Table 5, entry 7). For comparison, in n-propanal without water, the l/b parameters were 7.6 and 2.9
after the same time (Table 7, entry 1 and 2). A similar effect was also observed in n-butanal. In this
solvent l/b ratio was only 1.7 (Table 5, entry 8) and increased to 7 when water was added (Table 5,
entry 9).
The observed decrease in the l/b ratio caused by the added aldehyde made it possible to explain the
decrease in l/b observed in all systems when the reaction time was extended. Thus, after a longer time,
the amount of aldehyde increased in the reaction mixture, and its interaction with the catalyst changed
the reaction course to the branched pathway. Although the nature of that interaction is not well defined
yet, its result is clearly seen in the regioselectivity decrease. The negative effect of aldehyde on the
reaction course was significantly diminished by water, which competed with aldehyde for a place in
the coordination sphere of the catalyst.
Table 5. Propene hydroformylation in the Rh(acac)(CO) /PPyr system in the presence of aldehydes
2
3
and water.
6
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10.1002/cctc.201700917
entry yield of
aldehydes
mol)
ald/Rh conver TOF
-sion
l/b
time
(min)
solvent (ml)
-1
TON
(min )
(
(%)
94
97
96
86
93
76
97
1
2
3
4
5
6
7
8
9
1
1
1
0.0245
0.0448
0.0279
0.0065
0.025
1633
2986
1860
433
36.3
19.9
12.4
9.6
7.6
2.9
7.2
11
8
45
n-propanal (1)
n-propanal (1)
150
150
45
n-propanal (1) + toluene (0.5)
n-propanal (0.5) + toluene (1)
n-propanal (0.5) + toluene (1)
n-propanal (1) + water (1)
n-propanal (1) + water (1)
n-butanal (1)
1667
226.7
2267
1333
2000
1640
180
11.1
5
150
45
0.0034
0.034
19.3
11
1.7
7
15.1
8.9
150
150
150
150
150
150
0.02
0.03
13.3
10.9
1.2
n-butanal(1) + water (1)
iso-butanal (1)
0
1
2
0.0246
0.0027
0.0059
1.2
1
*
*
n-butanal (1)
393
2.62
1.8
n-butanal (1) + water (1)
-5
Reaction conditions: Rh(acac)(CO) (1.5∙ 10 mol), PPyr /Rh =13), propene/H /CO = 5 bar/5 bar/5 bar
2
3
2
*
80º C, autoclave 100 ml. PPh3
The studies of propene hydroformylation catalyzed by catalytic systems composed of Rh(acac)(CO)2
and phosphines, PPh , PCy , PPh Pyr, PPh(Pyr) , PPyr , made it possible to conclude that the reaction
3
3
2
2
3
rate and l/b regioselectivity increased with an increase in the number of pyrrolyl groups present in
phosphine. As expected, stronger -acceptor ligands facilitated higher reaction regioselectivity. In the
presence of PPh , 0.0084 mol of aldehydes was formed in 150 min with l/b = 2.3. The results obtained
3
with pyrrolylphosphines, PPh Pyr, PPh(Pyr) , PPyr , were significantly better, and the amount of
2
2
3
aldehydes increased to 0.03, while l/b reached values up to 8.6 for PPyr (Fig. 1).
3
7
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10.1002/cctc.201700917
2
2
1
1
5
1
4
3
50 min
0 min
0 min
2
0.8
0
5
0
5
0
1
6.2
1
0.5
8
.6
4
.6
4
.2
4
.5
3
2.8
.3
2
PPh3
PPh2Pyr
PPhPyr2
PPyr3
Phosphine
Fig. 1. Dependence of l/b on the kind of phosphine and reaction time
The highest selectivity to the linear aldehyde was obtained in reaction performed in the mixture of
solvents, toluene/water, with the most -acceptor ligand, PPyr . Water also improved regioselectivity
3
of the reaction with PPh Pyr as the modifying ligand and an l/b increase from 5.0 to 7.9. In contrast,
2
the selectivity of hydroformylation performed with PPh , PCy , and PPh(Pyr) was practically not
3
3
2
affected by the addition of water to toluene (Fig. 2). In general, a solution containing 1 ml of toluene
and 1 ml of water gave the highest regioselectivity in all the studied systems.
3
2
2
0
5
0
5
0
5
0
2
7.1
2
2.2
18.2
1
7.2
1
5.9
l/b
15
1
1
2.3 12.2
1
7.9
5
.6
5
4
.7
3 3.1
.7
2.8
2
1
.43
1
.51.43 1.53
PCy3
PPh3
.5 tol
PPh2Pyr
1.5tol + 0.5 w
PPhPyr2
1 tol 1tol +1w
PPyr3
1
Fig. 2. Effect of water on the regioselectivity of propene hydroformylation in the [Rh(acac)(CO) ]/P
2
systems (P = PPh , PCy , PPh Pyr, PPh(Pyr) and PPyr )
3
3
2
2
3
8
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10.1002/cctc.201700917
The presence of water has an influence not only on hydroformylation regioselectivity but also on the
reaction yield. It can be illustrated by changes in TON values caused by the addition of water to
toluene (Fig. 3). In conclusion, a higher productivity of the catalytic system was observed in solutions
containing 1.5 ml of toluene and 0.5 ml of water. Under these conditions, a rhodium catalyst modified
with PPyr was the best one. In all systems, with the exception of PPh Pyr, the addition of water
3
2
increased the reaction rate.
4
97
4
22
419
3
73
3
3
66
47
3
00
297
76
2
86
2
2
55
TON
2
33
2
26
2
81
13
207
00
2
1
1
73
1
33
1
27
PCy3
PPh3
PPh2Pyr
PPhPyr2
PPyr3
1
.5 tol 1.5tol + 0.5 w 1 tol 1tol +1w
Fig. 3. Effect of water on the rate (TON) of propene hydroformylation in the [Rh(acac)(CO) ]/P
2
systems (P = PPh , PCy , PPh Pyr, PPh(Pyr) and PPyr ).
3
3
2
2
3
Conclusions
Propene hydroformylation is a highly relevant industrial process, however our studies have not been
done in an industrially representative way. Nevertheless, simple modification of the catalytic
conditions by addition of water to the system containing -acceptor PPyr , is very efficient in
3
increasing of n-butanal yield. The l/b ratio as high as 27 can not be obtained by changing of other
reaction parameters. Therefore such modification could be considered for an eventual testing under
industrial conditions.
Hydroformylation selectivity depends not only on the kind of phosphine used but also on the
reaction time. In all systems, selectivity decreased when the reaction time was extended. Interestingly,
a decline in the l/b value was the greatest for PPyr , whereas the l/b ratio changed only slightly over
3
time for PPh (Pyr) and PPh . The observed changes of regioselectivity can be explained by the
2
3
influence of aldehyde formed as a reaction product. Considering the obtained results, one can propose
the nonbonding interaction of aldehyde with the catalytically active rhodium-hydrido species, which
results in H insertion according to the Marcovnikov rule. This provides the formation of the branched
9
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ChemCatChem
10.1002/cctc.201700917
aldehyde. The opposite situation is observed for water molecules shifting the reaction pathway
to the linear isomer.
The studied system is biphasic, formed by organic phase containing toluene and
aldehydes and water phase as a second one. The observed influence of water on the reaction
rate can be discussed in term of “on water” concept which is based on solution – phase
interactions [34]. The interfacial nature of the “on water” reaction was underlined on the basis
of theoretical calculations [35]. Our previous results concerning hydroformylation of 1-
hexene, diolefins and alkynes were also commented in this way [33, 36].
In these studies we found that increase of l/b value caused by the added water, can be
correlated with -acceptor properties of phosphorus ligand present in the system [37]. To
explain this effect we propose to consider interactions of water molecules with rhodium
catalytic intermediates. Accordingly, one transition state, rhodium-hydrido-olefin species,
would be more H-bonded to the surface than the second one. As a result the linear aldehyde is
mainly formed. We hope that our assumption will be confirmed by DFT calculations which
are in progress.
Experimental
Materials
The rhodium complex Rh(acac)(CO)2 was synthesized according to the literature [38]. N-
pyrrolylphosphine ligands, PPyr , PPh(Pyr) , and PPh Pyr, were synthesized as described in the
3
2
2
literature [15]. Triphenylphosphine (PPh ) was purchased from Avocado; propene was purchased from
3
Air Liquide; hydrogen (H , 99.999%) and carbon monoxide (CO, 99.97%) were procured from Air
2
Products.
Hydroformylation of propene
Hydroformylation reactions were carried out in 100 ml stainless steel autoclaves, provided with a
manometer, a thermostat, a magnetic stirrer, and a gas inlet/outlet system. The catalyst, Rh(acac)(CO)2
-5
(
1.5 × 10 mol), a 13-fold excess of PPh , PPyr , PPh Pyr, or PPh(Pyr) , was introduced into the
3 3 2 2
autoclave. Next, 2 ml of toluene (solvent) and 0.25 ml of cyclohexane (internal standard) were added
under a dinitrogen atmosphere. The autoclave was closed, pressurized with propene (5 bar) and then
with the synthesis gas (H :CO =1:1) to 15 bar and heated to 80 °C. At the indicated time, the autoclave
2
was cooled to room temperature and the residual gases were depressurized. The products were
separated by vacuum transfer, and analyzed by means of GC and GC-MS (Hewlett Packard).
1
0
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ChemCatChem
10.1002/cctc.201700917
Acknowledgements
This work was done within the co-operation between Grupa Azoty Zaklady Azotowe Kędzierzyn S.A.
and Faculty of Chemistry, University of Wroclaw with the financial support from Polish Ministry of
Development under the grant POIR.02.01.00-00-0074/15-01.
References
1
. Applied Homogenous Catalysis with Organometallic Compounds: A Comprehensive Handbook in
Two Volumes, ed. B. Cornils and W. A. Herrmann, VCH Weinheim, 1996.
. Rhodium Catalysed Hydroformylation, ed. P. W. N. M. van Leeuwen and C. Claver, Kluwer
Academic Publisher, Dordrecht, 2000.
. Metal Catalysis in Industrial Organic Processes, ed. G. P. Chiusoli and P. M. Maitlis, RSC
Publishing, 2006.
. Transition Metals for Organic Synthesis. Building Blocks and Fine Chemicals, ed. M. Beller and C.
Bolm, Wiley-VCH Verlag GmbH & Co. KGaA, 2004.
. Hydroformylation. Fundamentals, Processes and Applications in Organic Synthesis, A. Borner, R.
Franke, Wiley-VCH, Verlag GmbH & Co. KGaA, 2016
2
3
4
5
6
7
. A. M. Trzeciak and J. J. Ziółkowski, Coord. Chem. Rev., 1999, 190–192, 883.
. A. M. Trzeciak, Hydroformylation in: Comprehensive Inorganic Chemistry II: from elements to
applications, ed. J. Reedijk and K. Poeppelmeier, Elsevier, Amsterdam, 2013, vol. 6, p. 25.
8
9
1
. I. Jacobs, B. de Bruin, J.N.H. Reek, ChemCatChem., 2015, 7, 1708 – 1718
. U. Gellrich, W. Seiche, M. Keller, B. Breit, Angew. Chem. Int. Ed., 2012, 51, 11033 – 11038
0. M. Kumar, R.V. Chaudhari, B. Subramaniam, T.A. Jackson, Organomet., 2014, 33, 4183 – 4191
1
1
1. R.P. Dias, M.S.L. Prates, Jr., W.B. de Almeida, W.R. Rocha, Int. J. Quantum Chem., 2011, 111,
280 – 1292
12. J.J. Carbó, F. Maseras, C. Bo, P.W.N.M. van Leeuwen, J. Am. Chem. Soc., 2001, 123, 7630 – 7637
13. S. Aguardo – Ullate, J.A. Baker, V. González – González, C. Müller, J.D. Hirst, J.J. Carbó, Catal.
Sci. Technol., 2014, 4, 979 - 987
14. O. Diebolt, H. Tricas, Z. Freixa, P.W.N.M. van Leeuwen, ACS Catal., 2013, 3,
128 - 137.
1
1
1
5. K.G.Moloy, J.L.Petersen, J. Am. Chem. Soc., 1995, 117, 7696-7710.
6. S.Fischer, J. Hoyano, I. Johnson, L.K. Peterson, Can. J. Chem., 1976, 54, 2706-2709.
7. A.M.Trzeciak, T. Głowiak, R. Grzybek, J.J. Ziółkowski, J. Chem. Soc. Dalton Trans.,
1
997, 1831-1837.
8. A.M. Trzeciak, P. Štěpnička, E. Mieczyńska, J.J. Ziółkowski, J. Organomet. Chem.,
005, 690, 3260-3267.
1
1
2
9. A.M. Trzeciak, B. Borak, Z. Ciunik, J.J. Ziółkowski, M. F. C. Guedes da Silva,
1
1
This article is protected by copyright. All rights reserved.

ChemCatChem
10.1002/cctc.201700917
A.J.L. Pombeiro, Eur. J. Inorg. Chem., 2004, 1411-1419.
2
2
2
2
2
2
0. M.P. Magee, W. Luo, W.H. Hersh, Organomet., 2002, 21, 362-372.
1. W. Gil, A.M. Trzeciak, J.J. Ziółkowski, Organomet., 2008, 27, 4131-4138.
2. R. Jackstell, H. Klein, M. Beller, K.-D. Wiese, D. Röttger, Eur. J. Org. Chem., 2001, 3871-3877.
3. B. Breit, J. Mol. Catal. A: Chem., 1999, 143, 143-154
4. B. Breit, Chem. Commun., 1996, 2071-2072.
5. Xue-Li Zheng, Cong-Ye Zheng, Fan-Ding Zhou, Hai-Yan Fu, Mao-Lin Yuan, Rui-
Xiang Li, B. Xu, H. Chen, Chinese Chemical Letters, 2016, 27, 678-680.
6. R. Luo, Hao-ran Liang, Xue-li Zheng, Hai-yan Fu, Mao-lin Yuan, Rui-xiang Li,
H. Chen, Catalysis Communications, 2014, 50, 29-33.
2
2
2
2
3
7. H. Janecko, A.M. Trzeciak, J.J. Ziółkowski, J. Mol. Catal., 1984, 26, 355-361.
8. E. Mieczyńska, A.M. Trzeciak, J.J. Ziółkowski, J. Mol. Catal., 1992, 73, 1-8.
9. E. Mieczyńska, A.M.Trzeciak, J.J. Ziółkowski, J. Mol. Catal., 1993, 80, 189-200.
0. L. Ziang, C. Li, X.L. Zheng, R.X. Li, H. Chen., Asian J. Chem., 2015, 27, 1371-1374
31. E. Tomás-Mendivil, R. Garcia-Álvares, C. Vidal, P. Crochet, V. Cadierno, ACS Catal., 2014, 4,
1901-1910.
3
3
3
2. A.M. Trzeciak, T. Głowiak, J.J. Ziółkowski, J. Organomet. Chem., 1998, 552, 159-164.
3. W. Alsalahi, A.M. Trzeciak, RSC Advances, 2014, 4, 30384-30391.
4. S. Narayan, J. Muldoon, M.G. Finn, V.V. Fokin, H.C. Kolb, K.B. Sharpless, Angew. Chem. Int.
Ed., 2005, 44, 3275-3279.
3
3
3
3
5. Y. Jung, R.A. Marcus, J. Am. Chem.Soc., 2007, 129, 5492-5502.
6. W. Alsalahi, A.M. Trzeciak, RSC Adv., 2014, 4, 30384-30391.
7. W. Alsalahi, R. Grzybek, A.M. Trzeciak, Catal. Sci. Technol., 2017, 7, 3097 - 3103
8. S. Yu. Varshavsky, T.G. Cherkasova, Zh. Neorg. Khim. 1967, 12, 1709.
1
2
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