CPC C08F 136/08 (2013.01) [A43B 1/10 (2013.01); B60C 1/0016 (2013.01); C07F 15/025 (2013.01)] | 17 Claims |
1. A process for the preparation of polyisoprene with a mainly alternating cis-1,4-alt-3,4 structure the process comprising:
polymerizing isoprene in the presence of a catalytic system, the system comprising:
(a) at least one pyridyl iron complex having general formula (I):
wherein:
R1 is selected from linear or branched C1-C20 alkyl groups, optionally substituted cycloalkyl groups, and optionally substituted aryl groups;
R2 is selected from linear or branched C1-C10 alkyl groups;
X, mutually identical or different, represents a halogen atom; or X is selected from linear or branched C1-C20 alkyl groups, —OCOR3 groups and —OR3 groups wherein R3 is selected from linear or branched C1-C20 alkyl groups;
n is 2 or 3;
(b) at least one co-catalyst selected from (b1) aluminoxanes having general formula (II):
(R4)2—Al—O—[—Al(R5)—O—]m—Al—(R6)2 (II)
wherein R4, R5 and R6, mutually identical or different, represent a hydrogen atom or a halogen atom; or R4, R5 and R6 are selected from linear or branched C1-C20 alkyl groups, cycloalkyl groups, and aryl groups, the groups being optionally substituted with one or more silicon or germanium atoms; and m is an integer ranging from 0 to 1000;
(b2) aluminum compounds having general formula (III):
Al(R7)(R8)(R9) (III)
wherein R7 represents a hydrogen atom, or is selected from linear or branched C1-C20 alkyl groups, cycloalkyl groups, aryl groups, alkylaryl groups, arylalkyl groups, alkoxy groups; R8 and R9, mutually identical or different, are selected from linear or branched C1-C20 alkyl groups, cycloalkyl groups, aryl groups, alkylaryl groups, and arylalkyl groups;
wherein the molar ratio between aluminum present in the co-catalyst and iron present in the pyridyl iron complex having general formula (I) ranges from 5 to 60.
|