Polyalkylpiperidines of formula I, ##STR1## wherein R.sup.1 is H or lower alkyl, R.sup.2 is H, O or a monovalent organic residue and Z is a divalent aromatic residue, are excellent light stabilizers for plastics. These compounds can be prepared from the according 4-oxopiperidines by Wittig-Horner reaction with diphosphonates of the formula IV, (ro).sub.2 (o)p--ch.sub.2 --z--ch.sub.2 --p(o)(or).sub.2 iv wherein R denotes lower alkyl, and subsequent hydrogenation of the resulting diolefines. The compounds of formula I are especially suitable for the stabilization of polyolefins, styrene polymers and polyurethanes.
                            式I的聚烷基
哌啶,其中R1为H或较低的烷基,R2为H、O或一价有机残基,Z为二价芳香残基,是塑料的优良
光稳定剂。这些化合物可以通过将相应的4-氧代
哌啶与式IV的
二膦酸酯进行Wittig-Horner反应,并用氢化反应获得的二烯烃制备而来,其中(RO)2(O)P-
CH2-Z-CH2-P(O)(OR)2 IV中R代表较低的烷基。式I的化合物特别适用于稳定聚烯烃、
苯乙烯聚合物和聚
氨酯。