乙烯系单体聚合阻聚反应(Ⅵ)——4-位取代2,2,6,6-四甲基哌啶-1氧自由基衍生物同醌类混合对MMA自由基聚合的阻聚效应

Inhibiting Effect of Radical Polymerization of Vinyl Monomers(Ⅵ)——Inhibiting Effects of Incorporation of 4-Substituted 2,2,6,6-Tetramethyl-piperidine-1-Oxyl and Its Derivatives with Quines on MMA

本文研究了几种4位取代2,2,6,6-四甲基哌啶-1-氧自由基及1-位取代的2,2,6,6-四甲基哌啶类化合物同醌类混合对甲基丙烯酸甲酯(MMA)自由基聚合的阻聚效应。

Inhibiting effects of some 4-subftitutcd 2,2,6,6-tctramethylpiperidine derivatives incorporated with quinone on MMA,initiated by benzoylperoxide,have been investigated by boiling,refractive index and electron spin resonance methods respectively.The result showed that when 2,2,6,6-tetramethyl-4-oxo-piperidine-i-oxyl(Ⅰ),2,2,6,6-tetramethyl-4-oxime-piperidine-i-oxyl(Ⅱ),2,2,6,6-teiramethyl-4-hydrooxy-piperidine-i-oxyl(Ⅲ)was incorporated with 1,4-benzoquinone,chlor-anil,1,4-naphthoquinonc or 9,10-phenonthrenequinone,inhibiting effects of these complexes would become more prominent than when nitroxyl radical was used alone.Especially incorporative effect of nitroxyl radical with l,4-benzoquinone was much more satisfying than that of other quinone.The control test also showed that it was not active for 1,4-bihydrooxy-2,2,6,6-tctramethylpiperidine(Ⅳ),1-(2-cyano-2-propyloxy)-4-oxo-2,2,6,6-tetramethylpiperidine(Ⅴ)and 1-phenoxy-4-hydroxy-2,2,6,6-tetramethyl-piperidine(Ⅵ)to inhibit polymerization of MMAat 101℃when it was used alone,but it was so satisfactory inhibitor of MMAas parent ni-troxyl radical when they were incorporated with quinone.The inhibition mechanism was studied by ESR spectral measurement.These research result demonstrated that the inhibiting mechanism of nitroxyl radical in the polymerization of MMAwas proposed to have couple and abstraction.hydrogen reaction and so on.