Dithiocarbamic esters
The present invention relates to dithiocarbamic esters, their preparation and their use for regulating the degree of polymerization during the polymerization of monomers, such as during the polymerization of chloroprene to give polychloroprene, and during the polymerization of 2,3-dichlorobutadiene to give poly-2,3-dichlorobutadiene, and during the copolymerization of chloroprene with 2,3-dichlorobutadiene. The present invention further relates to polymers which are obtainable via the polymerization of monomers in the presence of the dithiocarbamic esters of the invention. The present invention also relates to polymers which contain end groups derived from the dithiocarbamic esters of the present invention.
1. The process for preparing a polymer by polymerizing monomers in the presence of a compound of the formula (I),
where
R is a halogen-substituted alkenyl radical,
and where
Z is either a substituted or unsubstituted heterocyclic radical which contains at least one nitrogen atom and which has linkage at one nitrogen atom to the —CS 2 —R group of formula (I) and which, in the parent form in which there is a hydrogen atom bonded to the nitrogen atom which has linkage to the —CS 2 R group of formula (I), has a pK a value in the range from 12 to 20,
or where
Z is a radical of the formula (II),
where
A and B have been selected independently of one another from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted acyl, substituted or unsubstituted aroyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkylsulphonyl, substituted or unsubstituted alkylsulphinyl, substituted or unsubstituted alkylphosphonyl, substituted or unsubstituted arylsulphinyl and substituted or unsubstituted arylphosphonyl.
2. A process according to claim 1 wherein the monomers contain either a vinyl group or a diene group.
3. A process according to claim 2 wherein at least one monomer contains a diene group.
4. A process according to claim 3 wherein at least one monomer is chloroprene and/or 2,3-dichlorobutadiene.