Stereoselective Ring-Opening Polymerization of rac-Lactide Catalyzed by Squaramide Derived Organocatalysts at Room Temperature  

作　　者：Xiao Jiang Na Zhao Zhibo Li 

机构地区：[1]Key Laboratory of Biobased Polymer Materials,Shandong Provincial Education Department,College of Polymer Science and Engineering,Qingdao University of Science and Technology,Qingdao,Shandong 266042,China [2]College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao,Shandong 266042,China

出　　处：《Chinese Journal of Chemistry》2021年第9期2403-2409,共7页中国化学（英文版）

基　　金：Financial support received from NSFC(Nos.21704048,22031005);the Department of Science and Technology of Shandong Province(No.ZR2020LFG014);the Taishan Scholars Constructive Engineering Foundation(No.tsqn20161031)is gratefully acknowledged.

摘　　要：Substa ntial progresses have bee n made toward the developme nt of meta I-free catalysts for stereoselective rin g-ope ning polymeriza-tion(ROP)of rac-lactide.Yet the discovery of organic catalysts effective at ambient temperature remains a major challenge.Here,the bifunctional H-bonding catalyst SQ-1 containing a basic tertiary amine and squaramide motif proved to be good candidate for the stereoselective ROP of rac-lactide at room temperature,yielding stereoregular polylactide with controlled molecular weights(up to 21.1 kg/mol)and high tacticity(PjESC up to 0.88).Furthermore,binary H-b on ding catalytic system con sisti ng of squaramides(SQ-2 to SQ-6)and 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU)could efficiently promote the ROP of rac-lactide at room temperature within short reaction time.Among them,the most bulky squaramide SQ-2 exhibited the best steroselectivity towards the ROP of rac-lactide without transesterification side reactions during the polymerization process.The resulting polylactides were proved to have controlled molecular weights as high as 22.2 kg/mol and narrow distributions(1.10-1.24).

关 键 词：Ring-opening polymerization ORGANOCATALYSIS SQUARAMIDE Polymers STEREOSELECTIVE 

分 类 号：O64[理学—物理化学]