Trialkyl Phosphites and Diaryliodonium Salts as Co-initiators in a System for Radical-Promoted Visible-Light-Induced Cationic Polymerization
作者:Thomas W. Nalli、Lee G. Stanek、Rebekka H. Molenaar、Krysia L. Weidell、Justin P. Meyer、Brandon R. Johnson、Timothy T. Steckler、Jay Wm. Wackerly、Missy Jo Studler、Kevin L. Vickerman、Stephen A. Klankowski
DOI:10.1021/jo302830r
日期:2013.4.19
phosphites ((RO)3P) can act as co-initiators for the diaryliodonium-induced cationic polymerization of cyclohexene oxide (CHO) or THF. A radical initiation step is also required, consistent with the essential role of a radical chain reaction of the phosphite with the iodonium salt to form polymerization-starting aryltrialkoxyphosphonium salts (ArP+(OR)3). We used the visible photolysis of phenylazoisobutyronitrile
亚磷酸三烷基酯((RO)3 P)可以作为二芳基碘鎓诱导的环己烯氧化物(CHO)或THF阳离子聚合的助引发剂。还需要自由基引发步骤,这与亚磷酸酯与碘鎓盐形成形成聚合反应的芳基三烷氧基phosph盐(ArP +(OR)3)的自由基链反应的基本作用相一致。我们使用苯基偶氮异丁腈(PAIBN)的可见光解作为自由基引发步骤。如在三(2,2,2-三氟乙基)亚磷酸酯(TFP)中那样,亚磷酸酯上存在多个氟取代基,可使聚合反应以亚磷酸酯的亲核攻击而进行的链转移量降至最低。在一个典型的实验中,双(4-叔叔用65W紧凑型荧光灯照射六氟磷酸正丁基苯基)碘鎓盐(0.05 M),TFP(0.1 M)和PAIBN(0.02 M)1 h,从而在使用平均分子量(M W)为25000。我们还使用竞争实验确定了苯基与CHO(k = 2×10 6 M –1 s –1)和TFP(k = 2×10 )反应的近似速率常数。8 M –1