Pyrolysis of Baltic amber in a wire-mesh pyrolysis reactor: structural comparison of the tars with amber extracts in NMP

A sample of Baltic amber believed to be about 40 million years old, has bee n pyrolysed in a wire-mesh reactor. Nearly all (99%) of the sample was foun d to volatilise; the condensable tar yield was about 82%. These tars and ex tracts in 1-methyl-2-pyrrolidinone (NMP), similar to 20% of the original am ber sample, have been characterised by size exclusion chromatography (SEC) and UV-fluorescence spectroscopy (W-F). Size exclusion chromatograms of the soluble fraction of the amber gave relatively low intensity signal, indica ting the lack of strongly absorbing chromophores. The profiles of the pyrol ysis tar were more intense, suggesting that the pyrolytic process promoted aromatisation of the original structures. SEC of the amber extracts showed the presence of apparently large molecular mass material, possibly up to se veral million units. The SEC of the tar showed lower molecular mass materia l than that of the extract, with less absorbance at longer wavelengths, sug gesting the presence of smaller polynuclear aromatic groups. Synchronous W- fluorescence spectra suggest that the tar consisted mainly of fragmentation products of larger molecular mass material, deriving mostly from the insol uble, probably partly cross-linked part of the original sample. (C) 2001 El sevier Science B.V. All rights reserved.