A theoretical study on the alkali metal carboxylate‐promoted <scp>L‐Lactide</scp> polymerization

Özen, Cihan; Satoh, Toshifumi; Maeda, Satoshi

doi:10.1002/jcc.26386

Cited by 10 publications

(10 citation statements)

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“…In the presence of cesium pivalate, the absorption peaks corresponding to the CO stretching vibration of AA and the C–O–C stretching vibration of EGE also showed a slight shift, implying that anhydrides and epoxides can be also activated by cesium pivalate. We can deduce that smart catalysis involves a multiactivation mechanism, and a similar mechanism was reported in the ROP of L-LA via experimental and computational studies. , …”

Section: Resultssupporting

confidence: 72%

“…In the present catalysts/alcohol initiators coexisting system, the carboxylate could be more prone to activate initiators or OH-terminated growing chain end via H-bonding rather than directly initiate the ring-opening of the activated epoxides via a nucleophilic attack. This renders the OH group sufficiently nucleophilic to undergo nucleophilic attack toward the activated monomer. ,,, Other potential side reactions, such as the self-propagation of EGE and transesterification, were also successfully suppressed during ROAC, as evidenced by the absence of corresponding mass populations. These results revealed that the present catalytic system exhibited controlled/living behavior (Figures S6 and S7).…”

Section: Resultsmentioning

confidence: 99%

“…The resulting carboxylate species is active enough to react with the cesium cation activated epoxide, thus forming a copolymer with a perfect alternating chemical structure. When the anhydride is completely consumed, the termini of the alternating copolymer are occupied by hydroxyl groups that can persist and finally switch on the ROP of the cyclic ester in the smart system to form a multiblock copolymer. , During the self-switchable polymerization, the ring-opening step may follow two possible mechanisms including the monometallic pathway and bimetallic pathway. ,,, …”

Section: Resultsmentioning

confidence: 99%

“…This renders the OH group sufficiently nucleophilic to undergo nucleophilic attack toward the activated monomer. 26,27,37,38 Other potential side reactions, such as the selfpropagation of EGE and transesterification, were also successfully suppressed during ROAC, as evidenced by the absence of corresponding mass populations. These results revealed that the present catalytic system exhibited controlled/ living behavior (Figures S6 and S7).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Smart Access to Sequentially and Architecturally Controlled Block Polymers via a Simple Catalytic Polymerization System

et al. 2021

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Self-switchable polymerization is an attractive strategy for precisely controlling the microstructures and monomer sequences of polymers. To date, catalysts for the polymerization are generally limited to metal complex catalysts and some organocatalysts. In this article, we report that simple, inexpensive, and environmentally benign alkali metal carboxylate catalysts smartly switch between the ring-opening alternating copolymerization of epoxides with cyclic anhydrides and the ring-opening polymerization of cyclic esters to create a single synthetic step and thus achieve sequence-controlled multiblock polyesters. This polymerization system shows extremely high effectiveness and versatility for different combinations of epoxides, cyclic anhydrides, cyclic esters, and initiators. As a result, various types of complex block copolymers, such as AB diblocks, BAB triblocks, star copolymers, hyperbranched copolymers, and CAB triblocks, can be simply prepared and postpolymerization modification can be performed. As a proof of concept, polyester-based elastomers and adhesives were successfully synthesized via one-step procedures by reasonably designing the monomer structures of triblock copolymers, showing great potential for industrial applications of polyesters.

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Section: Resultssupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

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Smart Access to Sequentially and Architecturally Controlled Block Polymers via a Simple Catalytic Polymerization System

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“…On the basis of these reactivity ratios, we concluded that the resultant polymers were most consistent with a nearly perfect triblock copolymer. Due to ≫ which was reported by Coates and Williams et al 22 , 35 , 40 – 42 , the slow insertion of epoxides is the rate-determining step for polyester formation (Supplementary Fig. 10 ).…”

Section: Resultsmentioning

confidence: 80%

One-step synthesis of sequence-controlled multiblock polymers with up to 11 segments from monomer mixture

et al. 2022

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Switchable polymerization holds considerable potential for the synthesis of highly sequence-controlled multiblock. To date, this method has been limited to three-component systems, which enables the straightforward synthesis of multiblock polymers with less than five blocks. Herein, we report a self-switchable polymerization enabled by simple alkali metal carboxylate catalysts that directly polymerize six-component mixtures into multiblock polymers consisting of up to 11 blocks. Without an external trigger, the catalyst polymerization spontaneously connects five catalytic cycles in an orderly manner, involving four anhydride/epoxide ring-opening copolymerizations and one L-lactide ring-opening polymerization, creating a one-step synthetic pathway. Following this autotandem catalysis, reasonable combinations of different catalytic cycles allow the direct preparation of diverse, sequence-controlled, multiblock copolymers even containing various hyperbranched architectures. This method shows considerable promise in the synthesis of sequentially and architecturally complex polymers, with high monomer sequence control that provides the potential for designing materials.

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Potassium Acetate/18‐Crown‐6 Pair: Robust and Versatile Catalyst for Synthesis of Polyols from Ring‐Opening Copolymerization of Epoxides and Cyclic Anhydrides^†

et al. 2022

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Comprehensive Summary Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge, because most of the catalysts exhibit poor tolerance to chain transfer agent (CTA). In this contribution, we demonstrated that potassium acetate (KOAc) and 18‐crown‐6 (18‐C‐6) combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high‐end group fidelity. Compared with KOAc, KOAc/18‐C‐6 pair could induce a much faster chain transfer between the active and dormant chains, and thus produce polyester polyols with narrow and monomodal distribution. In addition, polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification (containing about 2% diacid residual as CTA) with an extremely low catalyst loading ([catalyst pair] : [anhydride] : [epoxide] = 1 : 50000 : 250000, [catalyst pair] = 0.0004 mol%). KOAc/18‐C‐6 could also promote the self‐switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures. Ring‐ opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride, finally producing polyester polyols with ABA‐type block structure.

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A theoretical study on the alkali metal carboxylate‐promoted L‐Lactide polymerization

Abstract: This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Cited by 10 publications

References 30 publications

Smart Access to Sequentially and Architecturally Controlled Block Polymers via a Simple Catalytic Polymerization System

Smart Access to Sequentially and Architecturally Controlled Block Polymers via a Simple Catalytic Polymerization System

One-step synthesis of sequence-controlled multiblock polymers with up to 11 segments from monomer mixture

Potassium Acetate/18‐Crown‐6 Pair: Robust and Versatile Catalyst for Synthesis of Polyols from Ring‐Opening Copolymerization of Epoxides and Cyclic Anhydrides^†

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A theoretical study on the alkali metal carboxylate‐promoted L‐Lactide polymerization

Abstract: This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Cited by 10 publications

References 30 publications

Smart Access to Sequentially and Architecturally Controlled Block Polymers via a Simple Catalytic Polymerization System

Smart Access to Sequentially and Architecturally Controlled Block Polymers via a Simple Catalytic Polymerization System

One-step synthesis of sequence-controlled multiblock polymers with up to 11 segments from monomer mixture

Potassium Acetate/18‐Crown‐6 Pair: Robust and Versatile Catalyst for Synthesis of Polyols from Ring‐Opening Copolymerization of Epoxides and Cyclic Anhydrides†

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Product

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Potassium Acetate/18‐Crown‐6 Pair: Robust and Versatile Catalyst for Synthesis of Polyols from Ring‐Opening Copolymerization of Epoxides and Cyclic Anhydrides^†