Polymerization of propylene carbonate

Abstract

SynopsisPolymerization of propylene carbonate was carried out at 12O-18O0C mainly with the use of diethylzinc catalyst. The polymer was a pale-yellow, viscous material of relatively low molecular weight (IOOO-iOOO). From the spectroscopic analysis of the polymer and its hydrolyzed product, the polymer was determined to have the structure CH, CH, CH3 CH, CH,where Y = 0.50, y = 0.25, and z = 0.25. This strongly suggested that the polymerization of propylene carbonate proceeded via 2,7-dimethyl-1,4,6,9-tetraoxaspiro[4,4]nonane (DTN) as an intermediate compound. Hence, DTN was synthesized and polymerized with the use of diethylzinc catalyst. The structure of the polymer thus prepared coincided exactly with that of the polymer from propylene carbonate. From these, a plausible mechanism of the polymerization was developed.

Hydrolysis of Ethylene Carbonate with Water and Hydroxide under Battery Operating Conditions

“…[5][6][7][8][9][10][11][12] There is a consensus among most authors that CO 2 is lost during the polymerization of EC and that the repeat units of the resultant polymers are a mixture of carbonate units and the corresponding oxide units. When Lewis acids (e.g., Al(acac) 3 or Ti(OBu) 4 ) 5,6 or transesterification catalysts (e.g., sodium stannate trihydrate or dibutyltin diacetate) 7-11 are used, the reaction temperature is 150 -170• C. For bases as initiators, 12 the reaction temperatures are even higher (150 -200• C), which makes it difficult to judge on the relevance of these reactions in lithium-ion batteries. However, the reaction conditions in polymerization studies [5][6][7][8][9][10][11][12] are typically selected to allow for a total conversion of the compound on a reasonable time scale, requiring high reaction rates, so that the reaction rate close to room temperature is not relevant for polymer science, but it can be of interest for the lithium-ion cell chemistry.…”

“…However, the reaction conditions in polymerization studies [5][6][7][8][9][10][11][12] are typically selected to allow for a total conversion of the compound on a reasonable time scale, requiring high reaction rates, so that the reaction rate close to room temperature is not relevant for polymer science, but it can be of interest for the lithium-ion cell chemistry. Probably the most thorough analysis with a base initiator was carried out by Lee and Litt,12 who studied the polymerization mechanism of ethylene carbonate using KOH as initiator at 150 -200…”

“…When Lewis acids (e.g., Al(acac) 3 or Ti(OBu) 4 ) 5,6 or transesterification catalysts (e.g., sodium stannate trihydrate or dibutyltin diacetate) 7-11 are used, the reaction temperature is 150 -170…”

“…Lithium-ion battery electrolytes typically rely on the cyclic carbonate ethylene carbonate (EC) as a co-solvent, mixed with linear carbonates like diethyl carbonate (DEC), dimethyl carbonate (DMC), and/or ethyl methyl carbonate (EMC) and a lithium salt, usually lithium hexafluorophosphate (LiPF 6 ). EC has unique properties in terms of the formation of a solid-electrolyte interphase (SEI) at the negative electrode (typically graphite) in lithium-ion batteries (LIBs).…”

The anionic ring-opening polymerization of five-membered cyclic carbonates fused to the cyclohexane ring

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] In contrast, the anionic ring-opening polymerization of the fivemembered ring is thermodynamically unfavorable and proceeds at a higher temperature (4150 1C), causing the elimination of carbon dioxide to produce a copolymer that consists of both carbonate and ether linkages. [20][21][22][23][24][25] However, we reported that the anionic ringopening polymerization of a five-membered cyclic carbonate (MBCG) (Figure 1) possessing the a,D-glucopyranoside structure proceeded even at 0 1C to produce an aliphatic polycarbonate without the elimination of carbon dioxide.…”