Stereochemistry of copolymerization of carbon dioxide with epoxycyclohexane

Abstract

Copolymerization of carbon dioxide with 1.2-epoxycyclohexane (EPCH) and with 1.4-epoxycyclohexane was examined. 1.2-Epoxycyclohexane was copolymerized with carbon dioxide bythe diethylzinc/water system, but 1.4-epoxycyclohexane was not polymerized by this catalyst. Determining the configuration of the EPCH unit in the EPCH/carbon dioxide copolymer by alkaline hydrolysis of the copolymer, it was found that the configuration at the carbon atom where ring opening of EPCH takes place was inverted during copolymerization. ZUSAMMENFASSUNG:Die Copolymerisation von Kohlendioxid mit 1.2-Epoxycyclohexan (EPCH) und mit 1.4-Epoxycyclohexan wurde untersucht. 1.2-Epoxycyclohexan wurde mit Kohlendioxid durch ein Diathylzink/Wasser-System copolymerisiert, das 1.4-Epoxycyclohexan jedoch nicht. Die Konfiguration der EPCH-Einheit in dem EPCH/Kohlendioxid-Copolymeren wurde durch alkalische Hydrolyse des Copolymeren bestimmt. Es wurde festgestellt, daB die Konfiguration an dem Kohlenstoffatom, an dem die Ringoffnung des EPCH eintritt, wahrend der Copolymerisation invertiert wird.

Copolymerization of carbon dioxide and propylene oxide with highly effective zinc hexacyanocobaltate(III)-based coordination catalyst

“…Since 1969, Inoue first disclosed the copolymerization of CO 2 with 1,2-epoxypropane [1] by ZnEt 2 -H 2 O (Scheme 1), researchers have paid much attention to explore various relating catalysts to ensue copolymerization of epoxide and CO 2 to afford aliphatic polycarbonate, and much progress has been made within past decades [2][3][4]. ZnEt 2 -protic compound, which was reported by Inoue and fully studied [5][6][7][8][9][10][11], generally showed low catalytic activity at about 10 grams of polymer per gram catalyst, and its low reaction rate prevented it from practical use. Other catalysts, such as rare earth catalyst [12], salen chromium chloride/ DMAP [13], etc were also reported.…”

Ring opening polymerization initiated by methylaluminoxane/AlMe3 complexes

“…In later years alkylaluminoxanes were scarcely used in the polymerization of aldehydes [11,12], oxetane [13,14], cyclic esters [10,[15][16][17][18][19][20][21] and cyclic carbonates [22][23][24], in the copolymerization of carbon dioxide with oxiranes [25] and oxetane [26], as well as in the copolymerization of olefins or styrene with acrylic monomers [27]. However, these reactions did not find wider practical application due to the high cost of catalysts and problems with the obtaining of aluminoxanes of reproducible structure and activity.…”

Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 4. Synthesis of side-chain liquid crystalline polycarbonates with mesogenic groups having tails of different lengths

“…In the copolymerization with CO 2 racemization does not take place 23,24) and chiral epoxides should give chiral polymers. In the present work the epoxide was always racemic and a special stereoregularity could therefore only be expected if the catalyst shows optical selectivity towards one of the two optical antipodes (usually only if the catalyst itself is chiral) or if the polymerization proceeds via the enantiomorphic site control or via the chain-end control mechanism.…”