6533b7defe1ef96bd1276546

RESEARCH PRODUCT

Preparation of monodisperse polyethylene oxides by gel permeation chromatography of discontinuous polymer-homologous series

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Abstract Starting from triethylene glycol, monodisperse polyethylene oxides of a molecular weight (MW) up to 2000 (degree of polymerisation (DP) During the first step the ditosylate of triethylene glycol is reacted with the sodium alkoxide of the same diol at room temperature. The condesation product (polymer homologues of triethylene glycol) was separated by molecular distillation and yielded the pure oligomers nonaethylene glycol (DP = 9, MW 414) and pentadecaethylene glycol (DP = 15, MW = 678), as proved by gel chromatography. During the next step the polymer homologues of nonaethylene glycol were synthesised in a similar way. The pure oligomers hepteicosa (DP = 27, MW = 1207) and pentatetracontaethylene glycol (DP = 45, MW = 2000) were isolated by preparative gel permeation chromatography on a polystyrene gel cross-linked with 2% divinylbenzene. Using a column, 200 × 5 cm, samples of up to 5 g could be separated. The separation of technical polyethylene oxides prepared by polymerisation indicated that up to a DP of approximately 27 adjacent oligomers are still resolved.