Process for the preparation of styrene derivatives extended at the double bond by ethylene and having a double bond remaining in the extension chain formed and new styrene derivatives extended with ethylene

A process for the preparation of styrene derivatives extended at the double bond with ethylene and having a double bond remaining in the extension chain formed, according to the formula ##STR20## in which R.sup.19 denotes hydrogen, C.sub.1 -C.sub.4 -alkylvinyl or chlorine,

• R.sup.38 denotes C.sub.1 -C.sub.4 -alkyl, C.sub.2 -C.sub.4 -alkenyl, C.sub.2 -C.sub.7 -acyl, fluorine chlorine or bromine, and
• m has a value of 4 to 104,
• with the exception of compounds wherein R.sup.19 is hydrogen and R.sup.38 is isobutyl or benzyl and m has the value 4,
• wherein a styrene derivative is reacted with ethylene in the presence of a nickel catalyst which carries a phosphorus-oxygen chelate ligand, at a temperature of 20to 160.degree. C. and an ethylene pressure of 1 to 200 bar, wherein the nickel catalyst is obtained by reaction of a nickel (O) compound, or a compound which can be converted in situ to a nickel (O) compound, with a phosphorus compound of the formula ##STR21## in which R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 independently of one another denote straight-chain or branched C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.1 -C.sub.20 -alkoxy, C.sub.3 -C.sub.8 -cycloalkyl, C.sub.6 -C.sub.12 -aryl, C.sub.6 -C.sub.12 -aryloxy, C.sub.7 -C.sub.15 -aralkyl or C.sub.7 -C.sub.15 -aralkoxy, where
• R.sup.7 can additionally denote hydrogen and
• R.sup.8 can additionally denote hydrogen, acyl or sulphonate,
• or a nickel catalyst which can be prepared by reaction of a nickel (O) compound, or a compound which can be converted in situ to a nickel (O) compound, with an adduct of a quinoid compound or maleic anhydride and a phosphine of the formula ##STR22## in which R.sup.4, R.sup.5 and R.sup.6 have the meaning mentioned.