Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2002-12-17
2004-05-18
Nazario-Gonzalez, Porfiro (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C502S152000, C502S155000, C556S059000, C556S470000, C556S482000, C568S809000, C568S814000, C568S881000
Reexamination Certificate
active
06737531
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to catalysts for the homogenous hydrogenation or hydrosilylation of carbonyl compounds. More specifically, the invention relates to processes for the hydrogenation of ketones and aldehydes using organometallic complexes of tungsten (W) and molybdenum (Mo) as catalysts or catalyst precursors. The invention also relates to processes for the hydrosilylation of ketones, aldehydes and esters using the same catalysts or catalyst precursors.
Hydrogenation reactions involve the addition of hydrogen to an organic compound whereby, for example, a ketone can be reduced to an alcohol. Prior art processes have generally required the presence of a heterogeneous catalyst with a solid phase of platinum, rhodium, palladium or nickel along with relatively high hydrogen pressure and elevated temperature.
Other hydrogenation processes currently in use employ inexpensive Mo and W metals to hydrogenate ketones under mild conditions of temperature and pressure. However, a limitation encountered with these processes is the decomposition of the catalysts, due to dissociation of a phosphine ligand.
Hydrosilylation reactions involve the addition of hydrosilane to ketones, aldehydes, or esters to form primarily alkoxysilanes. Prior art hydrosilylation processes have also required rhodium, platinum or palladium complexes as catalysts.
Thus, traditional homogeneous catalysts for hydrogenation or hydrosilylation of ketones or aldehydes use precious metals such as platinum (Pt), rhodium (Rh), iridium (Ir) or ruthenium (Ru), which are expensive and, therefore, frequently uneconomical. In contrast, the catalysts of the present invention, which use either molybdenum (Mo) or tungsten (W), are prepared with less expensive metals, and, therefore, offer economic advantages.
SUMMARY OF THE INVENTION
The present invention relates to catalysts and processes that use the catalysts for the homogeneous catalytic hydrogenation of ketones and aldehydes to alcohols with H
2
as the stoichiometric redundant and organometallic tungsten (W) and molybdenum (Mo) complexes as the catalysts.
The present invention also relates to catalysts and processes for the hydrosilylation of ketones, aldehydes or esters, represented by the formulas R(C═O)R
1
, R(C═O)H or R(CO
2
)R
1
. The functional groups R and R
1
are selected from hydrogen, C
1-30
hydrocarbyl radicals and substituted-hydrocarbyl radicals, which can be the same or different.
The catalyst or catalyst precursor includes an organometallic complex represented by the formula I
[CpM(CO)
2
(NHC)L
k
]
+
A
−
I
wherein M is a molybdenum or tungsten atom; Cp is substituted or unsubstituted cyclopentadienyl radical represented by the formula [C
5
Q
1
Q
2
Q
3
Q
4
Q
5
], wherein Q
1
to Q
5
are independently selected from the group consisting of H radicals, hydrocarbyl radicals and substituted hydrocarbyl radicals, halogens (F, Cl, Br, I), halogen-substituted hydrocarbyl radicals, and radicals represented by the formulas —OR′, —C(O)R′, —CO
2
R′, —SiR′
3
, —NR′R″ wherein R′ and R″ are independently selected from the group consisting of H radicals, hydrocarbyl radicals, halogens, and halogen-substituted hydrocarbyl radicals, wherein further Q
1
to Q
5
radicals can be optionally linked to each other to form a stable bridging group; NHC is any N-heterocyclic carbene ligand, L is either any neutral electron donor ligand wherein k is a number from 0 to 1 or L is an anionic ligand wherein k is 2, and A
−
is an anion.
In an embodiment, the catalysts of the invention can be prepared by reacting a metal hydride represented by the formula II:
CpM(CO)
2
(NHC)H II
with a hydride removing agent selected from BR
3
or a compound represented by formula Y
+
A
−
, wherein Y
+
is selected from the group consisting of (aryl)
3
C
+
, (aryl)
2
HC
+
, C
7
H
7
+
, R
3
NH
+
, Ag
+
and (C
5
R
5
)
2
Fe
+
, wherein R is a hydrocarbyl or substituted hydrocarbyl, A
−
is an anion selected from the group consisting of BF
4
−
, PF
6
−
, SbF
6
−
, CF
3
SO
3
−
, CB
11
H
12
−
, CB
9
H
10
−
CB
9
H
5
X
5
−
; CB
11
H
6
X
6
−
; wherein X is F Cl, Br or I, HBR
3
−
, wherein R is hydrocarbyl or substituted hydrocarbyl, and [(M′)Z
1
Z
2
. . . Z
n
]
−
, M′ is an element selected from atoms of group 13, n is the total number of Z ligands or n is 4, and Z
1
to Z
n
are independently selected from the group consisting of H radical, C
1-20
hydrocarbyl radical, substituted hydrocarbyl radical, halogens, halogen-substituted hydrocarbyl radical, hydrocarbyl-, halogen-substituted hydrocarbyl organometalloid radical, —OR, —C(O)R′, —CO
2
R′, and —NR′R″, wherein R′ and R″ are independently selected from the group consisting of H radicals, C
1-20
hydrocarbyl radical, halogens, and halogen-substituted hydrocarbyl radical; Z
1
to Z
n
radicals can be optionally linked to each other to form a stable bridging group. In the metal hydride of formula II, Cp, M and NHC are as described herein above.
The process for catalytic hydrogenation includes contacting an organic compound which contains at least one reducible functional group selected from the group consisting of R(C═O)R
1
and R(C═O)H, wherein R and R
1
are each independently selected from hydrogen (H) or any C
1
-C
20
hydrocarbyl or substituted-hydrocarbyl radical with hydrogen in the presence of a catalyst to form a reaction mixture, wherein the catalyst comprises an organometallic complex described above and represented by the formula:
[CpM(CO)
2
(NHC)L
k
]
+
A
−
I
wherein Cp, M, NHC, L
k
and A
−
are as described hereinbelow.
The process for catalytic hydrosilylation includes contacting an organic compound which contains at least one functional group selected from the group consisting of R(C═O)R
1
, R(C═O)H, and R(CO
2
)R
1
, wherein R and R
1
are each independently selected from hydrogen (H) or any C
1
-C
30
hydrocarbyl or substituted-hydrocarbyl radical in the presence of hydrosilane with a catalyst to form a mixture, wherein the catalyst comprises an organometallic complex described above and represented by the formula:
[CpM(CO)
2
(NHC)L
k
]
+
A
−
I
wherein Cp, M, NHC, L
k
and A
−
are as described hereinbelow.
The hydrogenation process is carried out in the presence of hydrogen at a pressure from 1 atmosphere to 5000 psi, and at a temperature of from −95° C. to 120° C. Preferably, the pressure is from about 1 atmosphere to about 800 psi and the temperature is from 20° C. to 100° C. The hydrosilylation process is carried out at a temperature from about −95° C. to about 120° C. and, in one aspect of the invention, from about 20° C. to about 100° C.
As a result of the present invention catalysts are provided with significantly higher lifetime and increased thermal stability. Moreover, the homogeneous organometallic Mo and W complexes of the present invention provide an effective hydrogenation or hydrosilylation catalyst at a considerably reduced cost over the prior art catalysts that use Pt, Rh, Ir or Ru complexes.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates broadly to catalysts or catalyst precursors used for a variety of hydrogenation or hydrosilylation reactions.
Catalysts
The active catalyst of the present invention is an organometallic complex represented by the formula:
[CpM(CO)
2
(NHC)L
k
]
+
A
−
I
wherein M is a molybdenum or tungsten atom; Cp is substituted or unsubstituted cyclopentadienyl radical represented by the formula [C
5
Q
1
Q
2
Q
3
Q
4
Q
5
], wherein Q
1
to Q
5
are independently selected from the group consisting of H radicals, hydrocarbyl radicals and substituted hydrocarbyl radicals, halogens (F, Cl, Br, I), halogen-substituted hyd
Bullock R. Morris
Dioumaev Vladimir K.
Bogosian Margaret C.
Brookhaven Science Associates LLC
Nazario-Gonzalez Porfiro
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