Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2000-03-07
2001-06-05
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C558S338000, C558S355000
Reexamination Certificate
active
06242633
ABSTRACT:
This application is a 371 of PCT/EP98/05733 filed Sep. 9, 1998.
DESCRIPTION
The present invention relates to a catalyst which comprises a nickel(0) complex which comprises at least one mono-, bi- or multidentate phosphonite ligand in which the phosphorus and one of the oxygen atoms of the phosphonite group are part of a 5- to 8-membered heterocycle, and to a process for preparing mixtures of monoolefinic C
5
-mononitriles by catalytic hydrocyanation in the presence of a catalyst of this type.
There is a great demand around the world for &agr;,&ohgr;-alkylenediamines which serve as an important starting material for the industrial preparation of polyamides. &agr;,&ohgr;-Alkylenediamines such as hexamethylenediamine are obtained almost exclusively by hydrogenation of the corresponding dinitriles. Almost all industrial routes for preparing hexamethylenediamine are therefore essentially variants of the preparation of adiponitrile, of which about 1.0 million tonnes are produced each year around the world.
K. Weissermel, H.-J. Arpe, Industrielle organische Chemie, 4th edition, VCH Weinheim, pages 266 et seq. describe four routes, which differ in principle, for preparing adiponitrile:
1. reductive amination of adipic acid with ammonia in the liquid or gas phase, with intermediate formation of the diamide;
2. indirect hydrocyanation of 1,3-butadiene via the intermediate 1,4-dichlorobutenes;
3. hydrodimerization of acrylonitrile in an electrochemical process; and
4. direct hydrocyanation of 1,3-butadiene with hydrogen cyanide.
In the last-mentioned process, monoaddition in a first stage results in a mixture of isomeric pentenonitriles which is, in a second stage, isomerized mainly to 3- and 4-pentenonitriles. Subsequently, in a third stage, adiponitrile is formed by anti-Markownikoff addition of hydrogen cyanide onto 4-pentenonitrile. This reaction takes place in the liquid phase in a solvent such as tetrahydrofuran, at a temperature in the range 30-150° C. under atmospheric pressure. The catalysts used for this are nickel complexes with phosphine or phosphite ligands and metal salt promoters. The abovementioned review does not describe phosphonite ligands integrated into a heterocycle for stabilizing the nickel.
“Applied Homogeneous Catalysis with Organometallic Compounds”, Volume 1, VCH Weinheim, pages 465 et seq. gives a general description of the addition, with heterogeneous and homogeneous catalysis, of hydrogen cyanide onto olefins. The catalysts used in these cases are in particular based on phosphine, phosphite and phosphinite complexes of nickel and palladium. Adiponitrile is prepared by hydrocyanation of butadiene mainly with the use of nickel(0) phosphite catalysts, in the presence or absence of a Lewis acid as promoter. The reaction can generally be divided into three steps: 1. Synthesis of mononitriles by hydrocyanation of 1,3-butadiene; 2. Isomerization; 3. Synthesis of dinitriles. In the formation of the monoadduct, a mixture of isomers is obtained and comprises, inter alia, 3-pentenonitrile and 2-methyl-3-butenonitrile.
Customary catalysts for the hydrocyanation of 1,3-butadiene are, in particular, the nickel(0)-phosphite catalysts already mentioned.
C. A. Tolman et al. describe in organometallics 3 (1984) 33 et seq. the catalytic hydrocyanation of olefins in the presence of nickel(0) phosphite complexes paying particular attention to the effects of Lewis acids on the addition of hydrogen cyanide.
Advances in Catalysis, Volume 33, 1985, Academic Press Inc., page 1 et seq. gives a review-type description of the hydrocyanation of olefins with homogeneous nickel catalysis. The catalysts employed are nickel(0) complexes with phosphine and phosphite ligands.
J. Chem. Soc., Chem. Commun. (1991) 1292 describes chiral aryl diphosphites as ligands for hydrocyanation catalysts. The phosphite group in these ligands is linked by two oxygen atoms to the 3- and 3′-positions of a 2,2′-binaphthyl unit with which they thus form a 7-membered heterocycle. It is also possible in addition for two of these heterocycles to be linked by a 2,2′-binaphthyl unit to give a bidentate chelating ligand.
J. Chem. Soc., Chem. Commun. (1991) 803 et seq. describes chelating diphosphite complexes of nickel(0) and platinum(0) which are analogous thereto but employ a biphenyl unit in place of a 2,2′-binaphthyl unit.
WO 95/28228 describes a process for the hydrocyanation of aliphatic monoolefins which may additionally have a nonconjugated nitrile group or a nonconjugated or conjugated ester group. The nickel(0) catalysts employed in this case likewise comprise bidentate phosphite ligands in which the phosphite groups are parts of aryl-fused heterocycles.
WO 95/29153 describes a process for the hydrocyanation of monoolefins employing catalysts based on zero-valent nickel and monodentate phosphite ligands. The phosphite group in these ligands is in turn, together with two of its oxygen atoms, part of an aryl-fused 7-membered heterocycle. The third oxygen atom of the phosphite group carries a t-butyl-substituted phenyl radical which may also have further substituents.
WO 96/11182 describes a process for the hydrocyanation of aliphatic, monoethylenically unsaturated compounds in which the ethylenic double bond is not conjugated with another unsaturated group or in which the ethylenic double bond is conjugated with an ester group. In this case, a nickel(0) catalyst based on a multidentate phosphite ligand is employed in the presence of a Lewis acid as promoter. The phosphite groups in these multidentate ligands are in turn constituents of aryl-fused heterocycles and may be bridged by aryl-fused groups.
WO 96/22968 describes a process for the hydrocyanation of diolefinic compounds and for the isomerization of the resulting nonconjugated 2-alkyl-3-monoalkenonitriles by reacting an acyclic, aliphatic diolefin with a source of hydrogen cyanide. This reaction takes place in the liquid phase. The hydrocyanation catalysts employed are similar to those described in WO 96/11182.
U.S. Pat. No. 5,512,695 has a disclosure content corresponding to that of WO 95/28228.
Besides the hydrocyanation catalysts described previously and based on mono-, bi- and multidentate phosphite ligands, catalysts based on phosphinite ligands are also known. J. Am. Chem. Soc. 116 (1994) 9869 et seq. and U.S. Pat. No. 5,484,902 describe catalysts for the enantioselective hydrocyanation of aromatic vinyl compounds based on a chiral, nonracemic, bidentate chelating phosphinite ligands. The ligand preferably employed in this case is a phenyl 2,3-bis-O-(3,5-bis(trifluoromethyl)phenyl)phosphino-4,6-O-benzylidene-&bgr;-D-glucopyranoside.
U.S. Pat. No. 5,523,453 describes a process for the hydrocyanation of monoolefins which may additionally have a cyano group in the presence of a Lewis acid as promoter and a nickel(0) catalyst. These catalysts have ligands based on chelating phosphinites in which two aryl-substituted phosphinite groups are linked together via their oxygen atom and an aryl-fused alkylene bridge.
None of the abovementioned references describes hydrocyanation catalysts based on phosphonite ligands where the phosphonite group is part of a 5- to 8-membered heterocycle.
U.S. Pat. No. 3,766,237 describes a process for the hydrocyanation of ethylenically unsaturated compounds which may have other functional groups, such as nitrites, in the presence of a nickel catalyst. These nickel catalysts have four ligands of the formula M(X,Y,Z) where X, Y and Z are, independently of one another, a radical R or OR, and R is selected from alkyl and aryl groups having up to 18 carbon atoms. However, only phosphines and phosphites are explicitly mentioned therein and employed in the examples of the hydrocyanation. On the other hand, there is no disclosure of the possibility of employing phosphonites in which the phosphonite group is part of a heterocycle as ligands for nickel(0) hydrocyanation catalysts.
It is an object of the present invention to provide novel catalysts based on zero-valent nickel which show good selectivity and good
Fischer Jakob
Siegel Wolfgang
BASF - Aktiengesellschaft
Keil & Weinkauf
McKane Joseph K.
Solola Taofiq A.
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