Cationic Ring-Opening Polymerization of Cyclic Ethers

Kubisa, Przemysław

doi:10.1016/b978-0-444-53349-4.00102-3

Cited by 23 publications

(30 citation statements)

References 168 publications

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“…Generally, four-membered and higher cyclic ethers polymerize by cationic mechanism only (with a few rather unusual exceptions that have been mentioned in literature). The basic mechanistic principles of the CROP of heterocycles are well understood, based on work carried out by various groups from the 1960ies to the 1980ies, summarized in excellent reviews by Kubisa and Penczek et al − The CROP is rarely used for the polymerization of EO or PO, since the formation of considerable amounts of cyclic polyether byproducts cannot be avoided, which is due to “backbiting” processes, i.e., intramolecular chain transfer. , For this reason and due to the low number of recent works on the CROP of epoxides this section of the current review is rather brief, and merely the basic principles will be outlined.…”

Section: Polymerization Of Alkylene Oxides: Methodsmentioning

confidence: 99%

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation

et al. 2015

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The review summarizes current trends and developments in the polymerization of alkylene oxides in the last two decades since 1995, with a particular focus on the most important epoxide monomers ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO). Classical synthetic pathways, i.e., anionic polymerization, coordination polymerization, and cationic polymerization of epoxides (oxiranes), are briefly reviewed. The main focus of the review lies on more recent and in some cases metal-free methods for epoxide polymerization, i.e., the activated monomer strategy, the use of organocatalysts, such as N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) as well as phosphazene bases. In addition, the commercially relevant double-metal cyanide (DMC) catalyst systems are discussed. Besides the synthetic progress, new types of multifunctional linear PEG (mf-PEG) and PPO structures accessible by copolymerization of EO or PO with functional epoxide comonomers are presented as well as complex branched, hyperbranched, and dendrimer like polyethers. Amphiphilic block copolymers based on PEO and PPO (Poloxamers and Pluronics) and advances in the area of PEGylation as the most important bioconjugation strategy are also summarized. With the ever growing toolbox for epoxide polymerization, a "polyether universe" may be envisaged that in its structural diversity parallels the immense variety of structural options available for polymers based on vinyl monomers with a purely carbon-based backbone.

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Section: Polymerization Of Alkylene Oxides: Methodsmentioning

confidence: 99%

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation

et al. 2015

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“… Poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) have found applications as lubricants, plasticizers, dispersants, nonionic surfactants, and building blocks of polyurethanes. , The high water-solubility and very low immunogenicity, antigenicity, and toxicity have made PEO the “gold standard” for any biocompatible applications. , Epoxide polymerizations typically occur through an anionic polymerization initiated by metal alkoxides, as this methodology can achieve precise molecular weight control over a wide range. Additionally, the development of metal-free polymerizations has seen renewed interest with amine-, NHC-, phosphazene-, and N-heterocyclic olefin (NHOs)-based catalysts, with newer catalysts providing higher polymerization rates and accessing higher molecular weights by eliminating side reactions. ,− …”

Section: Heterocyclic Monomersmentioning

confidence: 99%

Recent Trends in Catalytic Polymerizations

et al. 2019

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Polymers have become one of the largest and most important materials we use in daily life. Their popularity has stemmed from their wide range of material properties combined with their low cost of production. Both of these attractive traits have in part been enabled by the development of catalytic polymerizations, which provide both high levels of control while also delivering high levels of productivity. In this Perspective, we highlight recent trends and achievements made in the growing field of catalytic polymerizations.

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“…For example, polyethylene oxide, which is obtained by the ring-opening polymerization of ethylene oxide, is used in a very wide range of products, such as pharmaceuticals, cosmetics, skincare products, detergents, tablets, and food additives, , due to its amphiphilicity and biocompatibility. In the ring-opening polymerization of oxiranes, living polymerization occurs mainly by anionic or coordination mechanisms. ,− Various strategies have been devised to enable living polymerization of oxiranes. ,− In contrast, in the cationic polymerization of oxiranes, side reactions such as backbiting reactions frequently occur, which results in low-MW oligomers, − and living polymerization is usually difficult. The controlled polymerization of oxiranes by the activated monomer mechanism was developed; − however, problems remain, such as minimizing the monomer concentration and a very long polymerization time.…”

Section: Introductionmentioning

confidence: 99%

Living Cationic Ring-Opening Homo- and Copolymerization of Cyclohexene Oxide by “Dormant” Species Generation Using Cyclic Ethers as Lewis Basic Additives

2021

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The living cationic ring-opening polymerization of cyclohexene oxide (CHO) was demonstrated to proceed using cyclic ethers as Lewis basic additives that potentially form "dormant" species through a reaction with the CHO-derived propagating species. The polymers obtained under suitable conditions had molecular weights close to the theoretical values and narrow molecular weight distributions. The formation of the dormant species was strongly supported by the generation of chain ends consisting of a cyclic ether additive and a quencher fragment, which was confirmed by 1 H NMR and ESI-MS analysis of the product polymers. The use of additives with appropriate basicity, such as hexamethylene oxide and tetrahydropyran, is of considerable importance for living polymerization. In addition, the living copolymerization of CHO and 1,4-epoxycyclohexene and the synthesis of alternating-like acid-degradable polymers with aliphatic aldehydes were also achieved.

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Cationic Ring-Opening Polymerization of Cyclic Ethers

Cited by 23 publications

References 168 publications

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation

Recent Trends in Catalytic Polymerizations

Living Cationic Ring-Opening Homo- and Copolymerization of Cyclohexene Oxide by “Dormant” Species Generation Using Cyclic Ethers as Lewis Basic Additives

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