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Characterization of lactone oligomers isolated by preparative SFC
Author(s) -
Ihara Eiji,
Tanabe Mari,
Nakayama Yuushou,
Nakamura Akira,
Yasuda Hajime
Publication year - 1999
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19990401)200:4<758::aid-macp758>3.0.co;2-b
Subject(s) - chemistry , degree of polymerization , polymerization , mass spectrum , polymer chemistry , glass transition , molecular mass , polystyrene , mass spectrometry , crystallography , organic chemistry , chromatography , polymer , enzyme
Oligomerization of ε ‐caprolactone and δ ‐valerolactone was performed by use of SmMe‐(C 5 Me 5 ) 2 (THF) 2 initiator, and the 26‐mer, 28‐mer and 30‐mer of ε ‐caprolactone were isolated in pure form by preparative SFC. The MALDI‐TOF mass spectrum of the 28‐mer indicates that the parent peak (3 256.1) emerges as 28‐mer + 2Na – H (3 256.9). The ESI mass spectrum of the 28‐mer indicates that the molecular weight (3 211.7) is consistent with the calculated value (3 211.9). In a similar manner, the 19‐, 25‐ and 32‐mers of δ ‐valerolactone were isolated. The MALDI‐TOF mass spectrum of the 19‐mer indicates that the parent peaks (1 896.6 and 1 879.9) emerge as 19‐mer + Na + K + MeOH – 1‐hexanol‐5‐one (1 896.3) and 19‐mer + 2Na + MeOH – 1‐hexanol‐5‐one (1 880.2). Glass transition and melting temperatures ( T g and T m ) of oligo‐ ε ‐caprolactones and oligo‐ δ ‐valerolactones increase with increasing degree of polymerization.