Dynamic NMR studies of equilibria involving active species in the polymerization of cyclic acetals. Reaction of the methoxymethyl cation with 5‐, 6‐, and 7‐membered cyclic acetals
Abstract
Abstract The cyclic acetals 1,3‐dioxolane (4a), 1,3‐dioxane (4b), and 1,3‐dioxepane (4c) give in their reactions with the methoxymethyl cation (1) a mixture of two isomeric tertiary oxonium ions: the simple products of cationation 5a‐c and the cationated rings 6, 7, 9, enlarged by two atoms. The equilibria for the studied monomers are shifted to the side of the oxonium ions as shown in the reaction schemes 2, 4, 5, and 6 (SbF‐6 or SbCIF‐5 being the corresponding anions). In the case of 4a the equilibrium is displaced almost completely to the enlarged ring 6, whereas for the other two cyclic acetals 4b and 4c the first cationated products 5b and 5c dominate. Application of the dynamic 1H NMR method allows the determination of the equilibrium constants of the reaction of 4a with 1.
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Onium ions can be prepared in a separate reaction or in situ.
“Onium-Ions can be prepared in a separate reaction or in situ [51].”
From Ring-Opening Polymerization—An Introductory Review (2013) · cites this paper as [51]
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References 8 · Cited by 18
- Authors
- Szymański, R., & Penczek, S.
- Affiliations
- Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk (PL)
- ORCID
- Szymański, Ryszard
- Venue
- Die Makromolekulare Chemie
- Publisher
- Wiley
- Published
- 1982-07-14
- Volume
- 183
- Issue
- 7
- Pages
- 1587-1602
- ISSN
- 0025-116X (ISSN-L)
- OpenAlex
- W1577781298
- Cited by
- 18
- References
- 8
- Citations by year
- 2016: 1 · 2013: 2 · 2012: 1
- FWCI
- 1.12
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Die Makromolekulare Chemie (publishedVersion)
- Topics
- Physical Sciences › Chemistry › Organic Chemistry › Chemical Reaction Mechanisms
- Physical Sciences › Chemistry › Organic Chemistry › Advanced Polymer Synthesis and Characterization
- Physical Sciences › Materials Science › Polymers and Plastics › Polymer Synthesis and Characterization
- Keywords
- cyclic acetals, 1,3-dioxolane, 1,3-dioxanes, 1,3-dioxepane, cationic polymerization, reaction equilibria, equilibrium constants, ring expansion, antimony hexafluoride, antimony pentafluoride
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