Polymerization of macrocyclic formals

Albrecht, Klaus; Fleischer, D.; Kane, Amat; Rentsch, Christoph; Thi, Quynh Van Tran; Yamaguchi, Hidemasa; Schulz, Rolf C.

doi:10.1002/macp.1977.021780323

Cited by 12 publications

(4 citation statements)

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“…Poly-(1,3,6,9,12-pentaoxacyclotetradecane) (P(4EO-MO)) reached a molar mass of only 5.2 kDa, likely because low ring strain in 14-membered 4EO-MO prevents high conversion. 50,51,56 The polymers were obtained in moderate yields (56−70%), and all data match previous reports of P(4EO-MO), 50,51,56 P(3EO-MO), 50,51,56−58 P(2EO-MO), 39,40,59,60 P(EO-MO), 54 and P(EO-2MO). 61 Typically, polyacetals exhibit poor thermal stability, presumably because residual acidic species catalyze ring-closing depolymerization at elevated temperatures.…”

Section: ■ Results and Discussionsupporting

confidence: 89%

“…Therefore, we tuned monomer concentration and equivalents of MeOTf or TMSOTf to obtain comparable molecular weights ( M n = 13.6–24.9 kDa) for poly(1,3,6,9-tetraoxacycloundecane) (P(3EO-MO)), poly(1,3,6-trioxocane) (P(2EO-MO)), poly(1,3-dioxolane) (P(EO-MO)), and poly(1,3,5-trioxepane) (P(EO-2MO)) (Table S1). Poly(1,3,6,9,12-pentaoxacyclotetradecane) (P(4EO-MO)) reached a molar mass of only 5.2 kDa, likely because low ring strain in 14-membered 4EO-MO prevents high conversion. ,, The polymers were obtained in moderate yields (56–70%), and all data match previous reports of P(4EO-MO), ,, P(3EO-MO), ,,− P(2EO-MO), ,,, P(EO-MO), and P(EO-2MO) …”

Section: Resultssupporting

confidence: 82%

“…Cyclic acetal monomers 1,3,6,9,12-pentaoxacyclotetradecane (4EO-MO), 1,3,6,9-tetraoxacycloundecane (3EO-MO), and 1,3,6-trioxocane (2EO-MO) were synthesized using a previously reported method. ,, These reactions were performed on a large scale (>30 g), wherein a given diol and paraformaldehyde were first step-growth polymerized in the presence of catalytic nonvolatile polyphosphoric acid, followed by depolymerization of the oligomeric product at high temperatures to give the desired cyclic acetal. 1,3-Dioxolane (EO-MO) was purchased commercially, and insertion of formaldehyde into EO-MO in the presence of an acid catalyst yielded 1,3,5-trioxepane (EO-2MO) .…”

Section: Resultsmentioning

confidence: 99%

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Modifying Li⁺ and Anion Diffusivities in Polyacetal Electrolytes: A Pulsed-Field-Gradient NMR Study of Ion Self-Diffusion

et al. 2021

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Polyacetal electrolytes have been demonstrated as promising alternatives to liquid electrolytes and PEO for rechargeable lithium-ion batteries; however, the relationship between polymer structure and ion motion is difficult to characterize. Here, we study structure-property trends in ion diffusion with respect to polymer composition for a systematic series of five polyacetals with varying ratios of ethylene oxide (EO) to methylene oxide (MO) units, denoted P(xEO-yMO), and PEO. We first use 7 Li and 19 F pulsed-field-gradient NMR spectroscopy to measure cation and anion self-diffusion, respectively, in polymer/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt mixtures. At 90 °C, we observe modest changes in Li + diffusivity across all polymer compositions while anion (TFSI − ) self-diffusion coefficients decrease significantly with increasing MO content. At a given reduced temperature (T − Tg), all polyacetal electrolytes exhibit faster Li + self-diffusion than PEO. Intriguingly, P(EO-MO) and P(EO-2MO) also show slower TFSI − anion self-diffusion than PEO at a given reduced temperature. Molecular dynamics simulations reveal that shorter distances between acetal oxygen atoms (O-CH2-O) compared to ether oxygens (O-CH2-CH2-O) promote more diverse, often asymmetric, Li + coordination environments. Raman spectra reveal that anion-rich ion clusters in P(EO-MO) and P(EO-2MO) lead to decreased anion diffusivity, which along with increased cation diffusivity, elucidate the viability of polyacetals as high-performance polymer electrolytes.

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Section: ■ Results and Discussionsupporting

confidence: 89%

Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

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Modifying Li⁺ and Anion Diffusivities in Polyacetal Electrolytes: A Pulsed-Field-Gradient NMR Study of Ion Self-Diffusion

et al. 2021

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“…The dimer is polymerizable under the same conditions as /3/ and after reaching the equilibrium it leads to the same oligomer distribution as the monomer and the polymer (see Fig.lo). All oligomers are colourless crystalline compounds.The melting points (see Table V) of the oligomers with even-numbered multiples of the monomers are always higher than the odd-numbered (47). The H-NMRspectra are nearly identical for all oligomers and lead to the conclusion, that all have analogous structure (compare Tables III and IV).…”

Section: Cyclic Oligomers Of the Triethylene Glycol Formalmentioning

confidence: 82%