Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1997-02-26
1999-07-13
Shah, Mukund J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
562406, 525340, C07C 6976, C07C 5110, C08C 1924
Patent
active
059229012
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE TECHNIQUE
The present invention relates to a method for producing a dimerization product of acrylonitrile, in particular, a straight chain dimer, such as adiponitrile, 1,4-dicyanobutene or 1,4-dicyanobutadiene, which is useful as an intermediate for producing hexamethylenediamine and adipic acid, both to be served for the starting materials of nylon 66, or as an intermediate for producing, for example, an antirusting agent or a vulcanization accelerator for rubbers.
BACKGROUND OF THE TECHNIQUE
As a method for producing adiponitrile or its precursor, namely, 1,4-dicyanobutene or 1,4-dicyanobutadiene, by dimerization of acrylonitrile, there have been proposed techniques, such as the one based on an electrolytic dimerization as given in Japanese Patent Kokai No. 27583/1987, the one based on a reaction using a halogenated ruthenium compound and an organic tin halide in the presence of hydrogen as given in Japanese Patent Kokai No. 9531/1994 and the one based on a reaction using a phosphate catalyst and an aromatic amide compound as given in Japanese Patent Kokai No. 1008/1993. The technique based on an electrolytic dimerization has, however, a problem that the energy cost in the production becomes higher and a special installation is required for the production. In the technique based on the reaction using a halogenated ruthenium compound or a phosphite catalyst, problems undesirable for an industrial production are brought about in, for example, that the reaction velocity is low, that the selectivity of the straight chain dimer is low and that the life of the catalyst is short.
Therefore, the object of the present invention is to provide an industrially acceptable method capable of producing a straight chain dimer of acrylonitrile efficiently at a high yield in a simple manner using a highly active catalyst exhibiting a superior stability, without suffering from occurrence of difficultly removable by-products.
DISCLOSURE OF THE INVENTION
The inventors have found that a straight chain dimer of acrylonitrile can be obtained at a high yield by using, as the dimerization catalyst, a ruthenium complex having ligands including cyclopentadiene or its derivative coordinating to the central ruthenium atom.
Thus, the method for producing a dimerization product of acrylonitrile according to the present invention comprises a step of dimerizing acrylonitrole in the presence of a ruthenium complex composed of a central atom of ruthenium and ligands including cyclopentadiene or its derivative coordinating thereto.
The ruthenium complex to be used according to the present invention serves for the dimerization catalyst and composed of a central atom of ruthenium and ligands coordinating thereto including at least one ligand of cyclopentadiene or its derivative. The ruthenium complex may be present as a polymer of such a ruthenium complex as above.
As the group of derivative of cyclopentadiene, there may be enumerated, for example, cyclopentadienyl, indenyl, fluorenyl and tetrahydroindenyl group, wherein the ring in these groups may have one or more substituent groups or atoms selected among alkyl groups having 1-10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, octyl and decyl; perhalogeno-alkyl groups having 1-10 carbon atoms, such as perfluoromethyl, perfluoroethyl and perfluorodecyl; aryl groups having 6-14 carbon atoms, such as phenyl, toluyl, mesityl, naphthyl, anthracenyl and biphenyl; alkoxyl groups having 1-6 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy and phenoxy; and halogen atoms, such as fluorine, chlorine, bromine and iodine.
The ruthenium complex to be used according to the present invention has a high activity with scarce reduction of the activity after a long duty operation and is superior in the stability.
The ruthenium complex to be used according to the present invention may have, in addition to the ligand of cyclopentadiene or its derivative, a further ligand of an oxy-hydrocarbon group as represented by RO (in which R represents a hydrocarbon radi
REFERENCES:
patent: 3671569 (1972-06-01), Chabardes et al.
patent: 4138419 (1979-02-01), Arakawa et al.
Kiso Yoshihisa
Suzuki Yasuhiko
Mitsui Chemicals Inc.
Ngo Tamthom T.
Shah Mukund J.
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