Catalyst compositions and their use for hydrogenation of nitrile rubber

1. A process of hydrogenating a nitrile rubber, the process comprising:

a) contacting a complex catalyst with hydrogen in the absence of a nitrile rubber at a temperature 75° C. to 200° C. to form a catalyst composition; and

b) hydrogenating the nitrile rubber in the presence of the catalyst composition, wherein the complex catalyst has the general formula (A)

where

M is ruthenium or osmium,

X 1 and X 2 are identical or different ligands,

L is an electron donating ligand, which can be linked or not linked with X 1 to form a cyclic structure,

R 1 is hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl or heteroaryl and

R 2 , R 3 , R 4 and R 5 are identical or different and are each hydrogen or an organic or inorganic substituent,

R 6 is H, alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, —C(═O)R, —C(═O)OR, —C(═O)N(R) 2 , —C(═S)R, —C(═S)SR, —C(═S)OR, —C(═S)N(R) 2 , —S(═O) 2 N(R) 2) —S(═O) 2 R, —S(═O)R or a group containing either a C═O or a C═S structural element adjacent to a carbon atom which is bound to Y,

n is 0 or 1,

wherein if n=1, then the element

shall mean that Y and (E) n are linked either by a single bond or by a double bond, wherein

(i) if Y and (E) n are linked by a single bond, then

 Y is oxygen (O), sulphur (S), N—R or P—R, and

 E is CH 2 , or

(ii) if Y and (E) n are linked by a double bond, then

 Y is N or P, and

 E is CH

wherein if n=0, then

Y is oxygen (O), sulphur (S), N—R or P—R and directly linked by a single bond to the phenyl moiety depicted above in formula (A), and

wherein R is hydrogen or alkyl, cycloalkyl, alkenyl, alkynyl, aryl or heteroaryl.

2. The process according to claim 1 , wherein in step a) the complex catalyst is selected from the group consisting of

(i) catalysts of general formula (A1),

wherein M, L, X 1 , X 2 , R 2 , R 3 , R 4 , R 5 , R 6 , n and E have the meanings mentioned for the general formula (A) in claim 1 ,

(ii) catalysts of general formula (A2),

wherein M, L, X 1 , X 2 , R 1 , R 2 , R 4 , R 5 , R 6 , n and E have the meanings mentioned for the formula (A) in claim 1 ,

(iii) catalysts of general formula (A3)

where

X 1 and X 2 are identical or different and shall mean 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 -alkylsulfonate, C6-C 2 4-arylsulfonate, C 1 -C 20 -alkylthiol, C 6 -C 24 -aryl thiol, C 1 -C 20 -alkylsulfonyl or C 1 -C 20 -alkylsulfinyl,

L is an electron donating ligand, which can be linked or not linked with X 1 to form a cyclic structure,

R 3 is chloro, fluoro, bromo, —C(═O)R, —C(═O)OR, —OC(═O)R, —C(═O)N(R) 2 , —C(═S)R, —C(═S)SR, —C(═S)OR, —C(═S)N(R) 2 , —S(═O) 2 N(R) 2 , —S(═O) 2 R, or —S(═O)R,

R 4 is H, halogen, nitro, cyano, C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 1 -C 20 alkylthio, —Si(R) 3 , —O—Si(R) 3 , C 6 -C 20 aryl, C 6 -C 20 aryloxy, C 2 -C 20 heterocyclic, C 2 -C 20 heteroaryl, —C(═O)R, —C(═O)OR, —C(═O)N(R) 2 , —C(═S)R, —C(═S)SR, —C(═S)OR, —C(═S)N(R) 2 , —S(═O) 2 N(R) 2 , —S(═O) 2 R or —S(═O)R,

R 2 and R 5 are each H, bromo (Br), iodo (I), C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 1 -C 20 alkylthio, —Si(R) 3 , —O—Si(R) 3 , C 6 -C 20 aryloxy, C 6 -C 20 aryl, C 2 -C 20 heterocyclic, C 2 -C 20 heteroaryl, —C(═O)OR, —C(═O)N(R) 2 , or —SO 2 N(R) 2 ,

R 6 is H, C 1 -C 20 alkyl, C 5 -C 20 aryl, C 2 -C 20 heterocyclic, C 2 -C 20 heteroaryl, —C(═O)R, —C(═O)OR, —C(═O)N(R) 2 , —SO 2 N(R) 2 or —N(SO 2 —R) 2 , —S(═O)R, or —S(═O) 2 R,

n is 0 or 1,

wherein if n=1, then the element

shall mean that Y and (E) n are linked either by a single bond or by a double bond, wherein

(i) if Y and (E) n are linked by a single bond, then

 Y is oxygen (O), sulfur (S), N—R or P—R and

 E is CH 2 , or

(ii) if Y and (E) n are linked by a double bond, then

 Y is N or P

 E is CH,

wherein if n=0, then

Y is oxygen (O), sulfur (S), N—R or P—R and directly linked by a single bond to the phenyl moiety depicted above in formula (A5), and

wherein in all above occurrences in formula (A3), R is identical or different and shall mean H, C 1 -C 20 -alkyl, C 3 -C 10 -cycloalkyl, C 2 -C 16 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, or C 2 -C 24 -heteroaryl, or if two substituents R are bound to the same atom, such two substituents A may also form a saturated or unsaturated cyclic structure together with the atoms to which they are bound,

(iv) catalysts of general formula (A4)

wherein M, L, Y, X 1 , X 2 , R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and n have the meanings given for general formula (A),

(v) catalysts of general formula (A5)

where

Y is oxygen (O) or —NR with R representing hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl or heteroaryl,

W is oxygen (O) or MR 7 with R 7 being hydrogen or straight chain or branched C 1 -C 20 alkyl,

R 15 represents straight chain or branched alkyl,

R 16 , R 17 , R 18 and R 19 are identical or different and represent hydrogen, halogen, alkyl, cycloalkyl, alkoxy, alkenyl, alkynyl, aryl or heteroaryl, and

L, R 1 , R 2 , R 3 , R 4 , R 5 and n shall have the meanings given for general formula A,

(vi) catalysts of general formula (A6)

where

M is ruthenium or osmium,

Z is oxygen (O) or sulfur (S),

Y is oxygen (O), sulfur (S), N—R 7 or P—R 7 , where R 7 has the meanings indicated below, X 1 and X 2 are identical or different ligands,

R 1 is H, alkyl, alkenyl, alkynyl or aryl,

R 2 , R 3 , R 4 and R 5 are identical or different and are each hydrogen, organic or inorganic substituents,

R 61 is H, 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, halogen, alkoxy, aryl or heteroaryl substituents,

R 62 is alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxy carbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkyl sulphonyl, each of which may optionally be substituted by one or more alkyl, halogen, alkoxy, aryl or heteroaryl substituents,

or where in the alternative R 61 and R 52 may form a cyclic structure together with the two adjacent carbon atoms to which they are bound,

L is a ligand,

R 7 is alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl which may each be optionally substituted by one or more alkyl, halogen, alkoxy, aryl or heteroaryl substituents, and

n is 0 or 1, and

(vii) catalysts of general formula (A7)

where

X 1 and X 2 are identical or different and shall mean 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 5 C 1 -C 20 -alkylsulfonate, C 6 -C 24 -arylsulfonate, C 1 -C 20 -alkylthiol, C 6 -C 24 -arylthiol, C 1 -C 20 -alkylsulfonyl or C 1 -C 20 -alkylsulfinyl,

L is an electron donating ligand, which can be linked or not linked with X 1 to form a cyclic structure,

Y is NR or PR,

R 3 is chloro, fluoro, bromo, —C(═O)R, —C(═O)OR, —OC(O)R, —C(═O)N(R) 2 , —C(═S)R, —C(═S)SR, —C(═S)OR, —C(═S)N(R) 2 , —S(═O) 2 N(R) 2 , —S(═O) 2 R, or —S(═O)R,

R 4 is H, halogen, nitro, cyano, C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 1 -C 20 alkylthio, —Si(R) 3 , —O—Si(R) 3 , C 6 -C 20 aryl, C 6 -C 20 aryloxy, C 2 -C 20 heterocyclic, C 2 -C 20 heteroaryl, —C(═O)R, —C(═O)OR, —C(═O)N(R) 2 , —C(═S)R, —C(═S)SR, —C(═S)OR, —C(═S)N(R) 2 , —S(═O) 2 N(R) 2 , —S(═O) 2 R or —S(═O)R,

R 2 and R 5 are each H, bromo (Br), iodo (I), C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 1 -C 20 alkylthio, —Si(R) 3 , —O—Si(R) 3 , C 6 -C 20 aryloxy, C 6 -C 20 aryl, C 2 -C 20 heterocyclic, C 2 -C 20 heteroaryl, —C(═O)OR, —C(═O)N(R) 2 , or —SO 2 N(R) 2 ,

R 6 is H, C 1 -C 20 alkyl, C 6 -C 20 aryl, C 2 -C 20 heterocyclic, C 2 -C 20 heteroaryl, —C(═O)R, —C(═O)OR, —C(═O)N(R) 2 , —SO 2 N(R) 2 , —N(SO 2 —R) 2 , —S(═O)R, or —S(═O) 2 R, and

wherein in all above occurrences in formula (A7), R is identical or different and shall mean H, C 1 -C 20 -alkyl, C 3 -C 10 -cycloalkyl, C 2 -C 16 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, or C 2 -C 24 -heteroaryl, or if two substituents R are bound to the same atom, such two substituents R may also form a saturated or unsaturated cyclic structure together with the atoms to which they are bound.

3. The process according to claim 1 , wherein the complex catalyst is selected from the group consisting of the below shown formulae, wherein Mes is in each case 2,4,6-trimethylphenyl, Ph is phenyl,

4. The process according to claim 1 , wherein the temperature in step a) is 80° C. to 200° C., and the contacting is done at a hydrogen pressure 0.5 MPa to 35 MPa.

5. The process according to claim 1 , wherein the hydrogenation in step b) is performed at a temperature 60° C. to 200° C., and at a hydrogen pressure of 0.5 MPa to 35 MPa.

6. The process according to claim 1 , wherein the nitrite rubber subjected to hydrogenation is a copolymer of at least one α,β-unsaturated nitrile, and at least one conjugated diene.

7. The process according to claim 1 , wherein the nitrile rubber subjected to hydrogenation is a terpolymer of at least one α,β-unsaturated nitrile, at least one conjugated diene, and one or more, further copolymerizable monomers selected from the group consisting of α,β-unsaturated monocarboxylic acids, their esters, their amides, α,β-unsaturated dicarboxylic acids, their mono- or diesters, their anhydrides and their amides.

8. The process according to claim 1 , wherein the process is performed in an organic solvent.

9. The process according to claim 8 , wherein the organic solvent is selected from the group consisting of dichloromethane, benzene, toluene, methyl ethyl ketone, acetone, tetrahydrofuran, tetrahydropyran, dioxane, cyclohexane and chlorobenzene.

10. The process according to claim 8 , wherein the organic solvent is chlorobenzene or methyl ethyl ketone.

11. The process according to claim 1 , wherein the complex catalyst is selected from the group consisting of

12. The process according to claim 1 , wherein the complex catalyst is

13. The process according to claim 1 , wherein:

the temperature in step a) is 80° C. to 200° C., and the contacting is done at a hydrogen pressure of 0.5 MPa to 35 MPa;

the hydrogenation in step b) is performed at a temperature of 60° C. to 200° C., and at a hydrogen pressure of 0.5 MPa to 35 MPa;

the nitrile rubber is one of:

a copolymer of at least one α,β-unsaturated nitrile, and at least one conjugated diene; and

a terpolymer of at least one α,β-unsaturated nitrile, at least one conjugated diene, and one or more, further copolymerizable monomers selected from the group consisting of α,β-unsaturated monocarboxylic acids, their esters, their amides, α,β-unsaturated dicarboxylic acids, their mono- or diesters, their anhydrides and their amides; and

the process is performed in an organic solvent selected from the group consisting of dichloromethane, benzene, toluene, methyl ethyl ketone, acetone, tetrahydrofuran, tetrahydropyran, dioxane, cyclohexane and chlorobenzene.

14. The process according to claim 13 , wherein:

the temperature in step a) is 80° C. to 160° C. and the hydrogen pressure is 3 MPa to 11 MPa;

the hydrogenation in step b) is performed at a temperature of 100° C. to 160° C. and at a hydrogen pressure of 3.0 MPa to 10 MPa;

the nitrile rubber is one of:

a copolymer of acrylonitrile and butadiene; and

a terpolymer of acrylonitrile, butadiene and one of the further copolymerizable monomers; and

the organic solvent is chlorobenzene or methyl ethyl ketone.

15. A process of hydrogenating a nitrile rubber without simultaneous metathesis of the nitrile rubber for maintaining the molecular weight of the nitrile rubber, the process comprising:

a) contacting a complex catalyst with hydrogen in the absence of a nitrile rubber at a temperature 75° C. to 200° C. to form a catalyst composition; and

b) hydrogenating the nitrile rubber in the presence of the catalyst composition without metathetic degradation of the nitrile rubber, wherein the complex catalyst has the general formula (A)

where

M is ruthenium or osmium,

X 1 and X 2 are identical or different ligands,

L is an electron donating ligand, which can be linked or not linked with KX to form a cyclic structure,

R 1 is hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl or heteroaryl and

R 2 , R 3 , R 4 and R 5 are identical or different and are each hydrogen or an organic or inorganic substituent,

R 6 is H, alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, —C(═O)R, —C(═O)OR, —C(═O)N(R) 2 , —C(═S)R, —C(═S)SR, —C(═S)OR, —C(═S)N(R) 2 , —S(═O) 2 N(R) 2) —S(═O) 2 R, —S(═O)R or a group containing either a C═O or a C═S structural element adjacent to a carbon atom which is bound to Y,

n is 0 or 1,

wherein if n=1, then the element

shall mean that Y and (E) n are linked either by a single bond or by a double bond, wherein

(i) if Y and (E) n are linked by a single bond, then

 Y is oxygen (O), sulphur (S), N—R or P—R, and

 E is CH 2 , or

(ii) if Y and (E) n are linked by a double bond, then

 Y is N or P, and

 E is CH

wherein if n=0, then

Y is oxygen (O), sulphur (S), N—R or P—R and directly linked by a single bond to the phenyl moiety depicted above in formula (A), and

wherein R is hydrogen or alkyl, cycloalkyl, alkenyl, alkynyl, aryl or heteroaryl.