THE NATURE AND FATE OF NATURAL RESINS IN THE GEOSPHERE - VIII - NMR AND PY-GC-MS CHARACTERIZATION OF SOLUBLE LABDANOID POLYMERS, ISOLATED FROM HOLOCENE CLASS-I RESINS

Citation
Dj. Clifford et al., THE NATURE AND FATE OF NATURAL RESINS IN THE GEOSPHERE - VIII - NMR AND PY-GC-MS CHARACTERIZATION OF SOLUBLE LABDANOID POLYMERS, ISOLATED FROM HOLOCENE CLASS-I RESINS, Organic geochemistry, 27(7-8), 1997, pp. 449-464
Citations number
50
Categorie Soggetti
Geochemitry & Geophysics
Journal title
ISSN journal
01466380
Volume
27
Issue
7-8
Year of publication
1997
Pages
449 - 464
Database
ISI
SICI code
0146-6380(1997)27:7-8<449:TNAFON>2.0.ZU;2-B
Abstract
Soluble polylabdanoids isolated by sequential solvent extraction have been characterized by liquid-state C-13- and H-1 NMR and C-13-H-1 HMQC (heteronuclear correlation) NMR spectroscopy in addition to solid-sta te NMR and Py-GC-MS techniques. Two Holocene resins originating from S antander, Colombia and Mombasa, Kenya were analyzed. Soluble polymers were isolated by extraction with a 1:1 (v/v) methylene chloride-methan ol mixture following sequential extractions with methylene chloride an d methanol. The molecular weight of polymer extracts was shown by GPC analyses to exceed that of non-polymeric occluded terpenoids. Py-GC-MS , solid-state C-13 CP/MAS and C-13 cross-polarization/depolarization N MR spectroscopy results indicated that chemical compositions of solubl e polymers isolated from immature resins are highly representative of the structure of corresponding insoluble polymers, i.e. polylabdatrien es. These data provide evidence for cross-linking or cyclization of si de-chain olefinic carbons during or shortly after polymerization. Gene rally, the characterization of soluble resin polymers by liquid-state NMR spectroscopy has proven to be an excellent means for investigating the maturation mechanism of polylabdanoid resinites, and has potentia l for furthering the application of Class I resinites as geothermal in dicators. (C) 1997 Elsevier Science Ltd. All rights reserved.