Steric and Polar Effects of the Cyclic Nitroxyl Fragment on the C−ON Bond Homolysis Rate Constant
作者:Hanns Fischer、Andreas Kramer、Sylvain R. A. Marque、Peter Nesvadba
DOI:10.1021/ma0512612
日期:2005.11.1
of the C−ON bond cleavage in new cyclic alkoxyamine models. The homolysis rate constants of 9 new alkoxyamines and 33 others given by the literature are analyzed with regards to the contributions of the polar inductive/field (σI) effect, the steric (Es) effect and the intramolecular hydrogen bonding (IHB) effect of the nitroxyl moieties, using the multiparameter equation established by Marque, i.e.,
1-alkoxy-polyallkyl-piperidine derivatives and their use as polymerization regulators
申请人:Ciba Specialty Chemicals Corporation
公开号:US06353107B1
公开(公告)日:2002-03-05
The present invention relates to 1-alkoxy-polyalkyl-piperidine derivatives containing a structural element of formula (I)
wherein
G1, G2, G3, G4 are independently C1-C6alkyl with the proviso that at least one is not methyl or G1 and G2 or G3 and G4, or G1 and G2 and G3 and G4 together form a C5-C12cycloalky group;
G5, G6 independently are H, C1-C18alkyl, phenyl, naphthyl or a group COOC1-C18alkyl and X represents a group such that the free radical X. derived from X is capable of initiating polymerization of ethylenically unsaturated monomers, with the proviso that compounds A1 and A2 are excluded
Further subjects of the invention are a polymerizable composition comprising a) at least one ethylenically unsaturated monomer and b) a 1-alkoxy-polyalkyl-piperidine derivative, a process for polymerizing ethylenically unsaturated monomers, and the use of 1-alkoxy-polyalkyl-piperidine derivatives for controlled polymerization. The intermediate N-oxyl derivatives, a composition of the N-oxyl derivatives with ethylenically unsaturated monomers and a free radical initiator X., as well as a process for polymerization are also subjects of the present invention.