Process for degrading nitrile rubbers in the presence of catalysts having an increased activity
View Patent ↗A process of degrading nitrile rubbers comprises subjecting them to a metathesis reaction in the presence of specific catalysts with increased activity.
1. A process for degrading a nitrile rubber, the process comprising subjecting the nitrile rubber to a metathesis reaction in the presence of a catalyst of the general formula (I),
where
M is ruthenium or osmium,
Y is oxygen (O), sulphur (S), an N—R 1 radical or a P—R 1 radical,
X 1 and X 2 are identical or different ligands,
R 1 is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl radical, each of which may optionally be substituted by one or more alkyl, halogen, alkoxy, aryl or heteroaryl radicals,
R 2 , R 3 , R 4 and R 5 are identical or different and are each hydrogen, organic or inorganic radicals,
R 6 is hydrogen or an alkyl, alkenyl, alkynyl or aryl radical, and
L is a ligand.
2. The process according to claim 1 , wherein L in the general formula (I) is a P(R 7 ) 3 radical, where the radicals R 7 are each, independently of one another, C 1 -C 6 -alkyl, C 3 -C 8 -cycloalkyl or aryl or a substituted or unsubstituted imidazolidine radical (“Im”).
3. The process according to claim 2 , wherein the imidazolidine radical (Im) has a structure of the general formula (IIa) or (IIb),
where
R 8 , R 9 , R 10 , R 11 are identical or different and are each hydrogen, straight-chain or branched C 1 -C 30 -alkyl, C 3 -C 20 -cycloalkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, C 1 -C 20 -carboxylate, C 1 -C 20 -alkoxy, C 2 -C 20 -alkenyloxy, C 2 -C 20 -alkynyloxy, C 6 -C 20 -aryloxy, C 2 -C 20 -alkoxycarbonyl, C 1 -C 20 -alkylthio, C 6 -C 20 -arylthio, C 1 -C 20 -alkylsulphonyl, C 1 -C 20 -alkylsulphonate, C 6 -C 20 -arylsulphonate or C 1 -C 20 -alkylsulphinyl.
4. The process according to claim 3 , wherein R 10 and R 11 in the imidazolidine radical (Im) are identical or different and are each straight-chain or branched C 1 -C 10 -alkyl, C 3 -C 10 -cycloalkyl, C 6 -C 24 -aryl, C 1 -C 10 -alkylsulphonate, or C 6 -C 10 -arylsulphonate.
5. The process according to claim 3 , wherein the imidazolidine radical (Im) has the structure (IIIa), (IIIb), (IIIc), (IIId), (IIIe) or (IIIf),
where Mes is in each case a 2,4,6-trimethylphenyl radical.
6. The process according to claim 1 , wherein X 1 and X 2 in the general formula (I) are identical or different and are each hydrogen, halogen, pseudohalogen, straight-chain or branched C 1 -C 30 -alkyl, C 6 -C 24 -aryl, C 1 -C 20 -alkoxy, C 6 -C 24 -aryloxy, C 3 -C 20 -alkyldiketonate, C 6 -C 24 -aryldiketonate, C 1 -C 20 -carboxylate, C 1 -C 20 -alkylsulphonate, C 6 -C 24 -arylsulphonate, C 1 -C 20 -alkylthiol, C 6 -C 24 -arylthiol, C 1 -C 20 -alkylsulphonyl or C 1 -C 20 -alkylsulphinyl.
7. The process according to claim 1 , wherein X 1 and X 2 in the general formula (I) are identical or different and are each halogen, benzoate, C 1 -C 5 -carboxylate, C 1 -C 5 -alkyl, phenoxy, C 1 -C 5 -alkoxy, C 1 -C 5 -alkylthiol, C 6 -C 24 -arylthiol, C 6 -C 24 -aryl or C 1 -C 5 -alkylsulphonate.
8. The process according to claim 1 , wherein X 1 and X 2 in the general formula (I) are identical and are each halogen, CF 3 COO, CH 3 COO, CFH 2 COO, (CH 3 ) 3 CO, (CF 3 ) 2 (CH 3 )CO, (CF 3 )(CH 3 ) 2 CO, PhO (phenoxy), MeO (methoxy), EtO (ethoxy), tosylate (p-CH 3 —C 6 H 4 —SO 3 ), mesylate (2,4,6-trimethylphenyl) or CF 3 SO 3 (trifluoromethanesulphonate).
9. The process according to claim 1 , wherein the radical R 1 in the general formula (I) is a C 1 -C 30 -alkyl, C 3 -C 20 -cycloalkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, C 1 -C 20 -alkoxy, C 2 -C 20 -alkenyloxy, C 2 -C 20 -alkynyloxy, C 6 -C 24 -aryloxy, C 2 -C 20 -alkoxycarbonyl, C 1 -C 20 -alkylamino, C 1 -C 20 -alkylthio, C 6 -C 24 -arylthio, C 1 -C 20 -alkylsulphonyl or C 1 -C 20 -alkylsulphinyl radical, each of which may optionally be substituted by one or more alkyl, halogen, alkoxy, aryl or heteroaryl radicals.
10. The process according to claim 1 , wherein the radicals R 2 , R 3 , R 4 and R 5 in the general formula (I) are identical or different and are each hydrogen, halogen, nitro, CF 3 or a C 1 -C 30 -alkyl, C 3 -C 30 -cycloalkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, C 1 -C 20 -alkoxy, C 2 -C 20 -alkenyloxy, C 2 -C 20 -alkynyloxy, C 6 -C 24 -aryloxy, C 2 -C 20 -alkoxycarbonyl, C 1 -C 20 -alkylamino, C 1 -C 20 -alkylthio, C 6 -C 24 -arylthio, C 1 -C 20 -alkylsulphonyl or C 1 -C 20 -alkylsulphinyl radical, each of which may optionally be substituted by one or more C 1 -C 30 -alkyl, C 1 -C 20 -alkoxy, halogen, C 6 -C 24 -aryl or heteroaryl radicals.
11. The process according to claim 1 , wherein the radical R 6 is hydrogen, a C 1 -C 30 -alkyl radical, a C 2 -C 20 -alkenyl radical, a C 2 -C 20 -alkynyl radical or a C 6 -C 24 -aryl radical.
12. The process according to claim 3 , wherein R 10 and R 11 in the imidazolidine radical (Im) are identical or different and are each one of:
straight-chain or branched C 1 -C 10 -alkyl;
straight-chain or branched C 3 -C 10 -cycloalkyl;
straight-chain or branched C 6 -C 24 -aryl;
straight-chain or branched C 1 -C 10 -alkylsulphonate; and
straight-chain or branched C 6 -C 10 -arylsulphonate.
13. The process according to claim 1 , wherein;
an amount of catalyst used is 5 to 1000 ppm based on the nitrile rubber used;
the nitrile rubber comprises polymers of repeating units of at least one conjugated diene, at least one α,β-unsaturated nitrile, and one or more further copolymerizable monomers;
the nitrile rubbers have a Mooney viscosity (ML 1+4 at 100° C.) of 30 to 70;
the metathesis is carried out without a coolefin or in the presence of a coolefin selected from the group consisting of ethylene, propylene, isobutene, styrene, 1-hexene or 1-octene; and
the degraded nitrile rubber is subsequently subjected to a hydrogenation in situ.
14. A process for degrading a nitrile rubber, the process comprising subjecting the nitrile rubber to a metathesis reaction in the presence of a catalyst of the general formula (IV)
where:
M is ruthenium or osmium,
L is a first ligand,
X 1 and X 2 are identical or different second ligands,
R 1 is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl radical, each of which may optionally be substituted by one or more alkyl, halogen, alkoxy, aryl or heteroaryl radicals, and
R 2 , R 3 , R 4 , R 5 are identical or different and are each hydrogen, organic or inorganic radicals.
15. The process according to claim 14 , wherein R 3 is organic other than —SO 2 N(CH 3 ) 2 .
16. The process according to claim 14 , wherein R 3 is hydrogen, halogen, nitro, CF 3 , alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl, each of which may optionally be substituted by one or more alkyl, alkoxy, halogen, aryl or heteroaryl radicals.
17. The process according to claim 14 , wherein R 2 , R 3 , R 4 , R 5 are identical or different and are each hydrogen, halogen, nitro, CF 3 , C 1 -C 30 -alkyl, C 3 -C 20 -cycloalkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, C 1 -C 20 -alkoxy, C 2 -C 20 -alkenyloxy, C 2 -C 20 -alkynyloxy, C 6 -C 24 -aryloxy, C 2 -C 20 -alkoxycarbonyl, C 1 -C 20 -alkylamino, C 1 -C 20 -alkylthio, C 6 -C 24 -arylthio, C 1 -C 20 -alkylsulphonyl or C 1 -C 20 -alkylsulphinyl, each of which may optionally be substituted by one or more C 1 -C 30 -alkyl, C 1 -C 20 -alkoxy, halogen, C 6 -C 24 -aryl or heteroaryl radicals.
18. A process for degrading a nitrile rubber, the process comprising subjecting the nitrile rubber to a metathesis reaction in the presence of a catalyst of the general formula (XVI),
where D 1 , D 2 , D 3 , and D 4 each have a structure of the general formula (XVII) which is bound via a methylene group to the silicon of the formula (XVI),
where:
L is a first ligand,
X 1 and X 2 are identical or different second ligands,
M is ruthenium or osmium,
Y is oxygen (O), sulphur (S), an N—R 1 radical or a P—R 1 radical,
R 1 is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl radical, each of which may optionally be substituted by one or more alkyl, halogen, alkoxy, aryl or heteroaryl radicals,
R 2 , R 3 , R 5 are identical or different and are each hydrogen, organic or inorganic radicals, and
R 6 is hydrogen or an alkyl, alkenyl, alkynyl or aryl radical.
19. The process according to claim 18 , wherein R 3 is organic other than —SO 2 N(CH 3 ) 2 .
20. The process according to claim 18 , wherein R 2 , R 3 , R 4 , R 5 are identical or different and are each hydrogen, halogen, nitro, CF 3 , alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl, each of which may optionally be substituted by one or more alkyl, alkoxy, halogen, aryl or heteroaryl radicals.