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Organolithium‐Initiated Polymerization of Olefins in Deep Eutectic Solvents under Aerobic Conditions
Author(s) -
SánchezCondado Alba,
Carriedo Gabino A.,
Presa Soto Alejandro,
RodríguezÁlvarez María J.,
GarcíaÁlvarez Joaquín,
Hevia Eva
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201900533
Subject(s) - chemistry , polymerization , reagent , reactivity (psychology) , eutectic system , organic chemistry , copolymer , anionic addition polymerization , polymer , chemical engineering , alloy , pathology , engineering , medicine , alternative medicine
Despite their ubiquitous presence in synthesis, the use of polar organolithium reagents under environmentally benign conditions constitutes one of the greatest challenges in sustainable chemistry. Their high reactivity imposes the use of severely restrictive protocols (e.g., moisture‐ and oxygen‐free, toxic organic solvents, inert atmospheres, low temperatures, etc.). Making inroads towards meeting this challenge, a new air‐ and moisture‐compatible organolithium‐mediated methodology for the anionic polymerization of different olefins (e.g., styrenes and vinylpyridines) was established by pioneering the use of deep eutectic solvents (DESs) as an eco‐friendly reaction medium in this type of transformation. Fine‐tuning of the conditions (sonication of the reaction mixture at 40 °C in the absence of protecting atmosphere) along with careful choice of components of the DES [choline chloride (ChCl) and glycerol (Gly) in a 1:2 ratio] furnished the desired organic polymers (homopolymers and random copolymers) in excellent yields (up to 90 %) and low polydispersities (IPD 1.1–1.3). Remarkably, the in situ‐formed polystyril lithium intermediates exhibited a great resistance to hydrolysis in the eutectic mixture 1ChCl/2Gly (up to 1.5 h), hinting at an unexpected high stability of these otherwise highly reactive organolithium species in these unconventional reaction media. This unique stability can be exploited to create well defined block‐copolymers.