Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2000-09-08
2002-04-30
Davis, Brian J. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C558S357000, C558S457000, C558S462000, C564S490000, C564S491000, C564S492000, C564S493000
Reexamination Certificate
active
06380420
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for manufacturing fatty acid nitrites and fatty amines by the cross-metathesis of normal alpha olefins and acrylonitrile in the presence of an organometallic cross-metathesis catalyst.
BACKGROUND OF THE INVENTION
Fatty amines are commercially valuable products which have various commercial uses, such as, in the manufacture of surfactants and soaps. An economically attractive method for making these products from olefins would be highly desirable. A process for the metathesis of olefins is taught in U.S. Pat. No. 4,681,956 using an organo-metallic catalyst containing a molybdenum or tungsten ligand complex. Similar catalysts that have been shown to be useful in the metathesis of olefins are also described in U.S. Pat. No. 5,146,033. The catalysts described in the aforesaid US Patents are usually referred to as Schrock catalysts. U.S. Pat. No. 5,175,370 describes a method for converting a fatty acid nitrile into a fatty amine. The hydrogenation of fatty nitriles to primary fatty amines is also described in U.S. Pat. No. 3,574,754.
Crowe et al. in “Acrylonitrile Cross Metathesis: Coaxing Olefin Metathesis Reactivity from a Reluctant Substrate”, J. Am. Chem. Soc., 117, 5162-5163 (1995) describes a method for the cross metathesis of acrylonitrile and normal alpha olefins to produce alkenylcyanides using a Schrock catalyst. Crowe et al.'s method has the advantage over previous methods of preparing unsaturated nitriles from n-alpha olefins of having high selectivity, i.e., minimizing the side reactions which reduce the yield of the desired fatty acid nitrile product. A major disadvantage of the process route described in Crowe et al. for the commercial production of unsaturated nitrites is the loss of the catalyst during processing. The Schrock catalyst used in the Crowe et al. method is expensive, and prior to the present invention, it has not been possible to immobilize the catalyst without affecting the cross-metathesis activity of the catalyst. Without some method for economically recovering the catalyst from the reaction mixture or for immobilizing the catalyst during the metathesis step, this route is commercially impractical.
SUMMARY OF THE INVENTION
One embodiment of the present invention is directed to a process for making a saturated fatty amine or saturated fatty diamine having a general structure according to the following formula:
R—CH
2
—CH
2
—CH
2
—NR′R″
wherein
R represents methyl or an alkyl moiety of the general formula CH
3
—(CH
2
)
n
— wherein n equals an integer of from 1 to about 18;
or alternatively R represents an alkyl amine moiety of the general formula NH
2
—CH
2
—CH
2
—(CH
2
)
m
— wherein m equals an integer of from 2 to about 17;
and R′ and R″ independently represent hydrogen, alkyl, alkylaryl, aryl, haloalkyl, haloalkylaryl, or haloaryl;
said process comprising:
(a) contacting a feed with acrylonitrile in the presence of an organometallic cross-metathesis catalyst for a time and under conditions preselected to promote cross-metathesis, said feed comprising at least one of a compound selected from the group consisting of a normal alpha olefin having from three to about twenty-one carbon atoms and an olefin of the general formula CH
2
═CH—(CH
2
)
x
—CH═CH
2
wherein x is an integer of from 1 to about 16, whereby either the corresponding alkenylcyanide intermediate or bis alkenylcyanide intermediate, respectively, is formed;
(b) hydrogenating the alkenylcyanide intermediate or bis alkenylcyanide intermediate of step (a) in the presence of a hydrogenation catalyst and in the presence of an amine of the general formula HNR′R″ under hydrogenation conditions sufficient to convert the intermediate to the corresponding saturated fatty amine or saturated fatty diamine of the general formula R—CH
2
—CH
2
—CH
2
—NR′R″; and
(c) recovering the saturated fatty amine or fatty diamine of step (b).
As used herein, R′ and R″ when they are other than hydrogen represent a hydrocarbon moiety which will usually contain from 1 to about 30 carbon atoms in the structure. The prefix “halo-” indicates the presence of a halogen substitution, i.e., the substitution of a fluorine, chlorine, bromine, or iodine atom for one or more hydrogen atoms that would otherwise be present in said moiety.
The alkenylcyanide intermediate referred to above is a fatty acid nitrile having the following general formula:
A—CH═CH—CN
wherein A represents methyl or an alkyl moiety of the general formula CH
3
—(CH
2
)
n
— wherein n equals an integer of from 1 to 18. It should be noted that the unsaturated carbon to carbon bond is always located next to the cyano moiety.
The bis alkenylcyanide intermediate would have the same general formula as the alkenylcyanide intermediate; however, in this instance, A would represent an alkyl amine moiety of the general formula NC—CH═CH—(CH
2
)
y
— wherein y equals an integer of from 2 to 16.
In the preferred embodiment of the invention, the organometallic cross-metathesis catalyst is immobilized and reused to catalyze additional cross-metathesis reactions. It has been found that a particularly advantageous method for immobilizing the cross metathesis catalyst is by dissolving the catalyst in an aprotic ionic liquid. Accordingly, another embodiment of the present invention is directed to a process for making an alkenylcyanide or bis alkenylcyanide characterized by the general formula:
A—CH═CH—CN
wherein
A represents methyl or an alkyl moiety of the general formula CH
3
—(CH
2
)
n
— wherein n equals an integer of from 1 to 18;
or alternatively A represents an alkyl amine moiety of the general formula NC—CH═CH—(CH
2
)
y
— wherein y equals an integer of from 2 to 16;
said process comprising the steps of:
(a) contacting in a cross-metathesis zone an organic phase with a ionic liquid phase comprising an organometallic cross-metathesis catalyst and an aprotic ionic liquid under reaction conditions and for a time preselected to promote cross-metathesis, said organic phase comprising a mixture of an organic solvent, acrylonitrile, and one or more compounds selected from the group consisting of a normal alpha olefin having from three to about twenty-one carbon atoms and an olefin of the general formula CH
2
═CH—(CH
2
)
x
—CH═CH
2
wherein x is an integer of from 1 to 16; and
(b) recovering from the cross-metathesis zone a cross-metathesis product consisting of an alkenylcyanide or bis alkenylcyanide from the organic phase.
The catalyst used in carrying out the cross-metathesis of the normal acrylonitrile with a normal olefin is broadly referred to as an organometallic cross-metathesis catalyst. Such catalysts contain an organometallic ligand usually containing a metal selected from tungsten, molybdenum, ruthenium, rhenium, and rhodium. The preferred catalysts for carrying out the cross-metathesis is a Schrock catalyst. As used herein, a Scrock catalyst means a catalyst as generally described in U.S. Pat. No. 4,681,956 and 5,146,033, the contents of both patents being herein incorporated by reference. Particularly useful as catalysts in the cross-metathesis reactions of the present invention are those Schrock catalysts having the following general formula:
M(NR
1
)(OR
2
)
2
CHR
3
)
wherein M is molybdenum or tungsten, and more preferably molybdenum; R
1
is alkyl, aryl, or arylalkyl; R
2
is alkyl, aryl, arylalkyl or halogen substituted derivatives thereof, particularly preferred is a fluorinated alkyl or fluorinated aryl; and R
3
is alkyl, aryl, or arylalkyl.
Particularly preferred are those Schrock catalysts containing molybdenum. Especially preferred as a catalyst is 2,6-diisopropylphenylimidoneophylidenemolybdenum (VI) bis(hexafluoro-t-butoxide) which has been successfully used to carry out the cross-metathesis step according to the present invention.
In a preferred embodiment of the present invention, the organometallic cross-metathesis catalyst is dissolved in an aprotic ionic liquid solvent. Ionic liquids
Driver Michael S.
Schinski William L.
Ambrosius James W.
Chevron U.S.A. Inc.
Davis Brian J.
Turner W. K.
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