SOLID-STATE ¹³C NMR QUANTITATIVE STUDY OF EUCALYPTUS TAR PITCHES

Abstract

Solid-state ¹³C NMR has been important to overcome analysis difficulties arising from the low solubility of carbonaceous materials. Its use provides accurate information about these materials. In this work, resonance techniques involving magic angle spinning with cross-polarisation (CP/MAS) or single pulse (SP/MAS) are used in conjunction with other analysis tools to quantitatively characterise Eucalyptus tar pitches and to follow their polymerisation reactions. The results showed that SP/MAS technique is more suitable for quantitative analyses, and that the pitches have a high content of aliphatic and oxygenated carbons. Moreover, they underwent thermal polymerisation, and the presence of AlCl₃ or formaldehyde permitted the use of lower treatment temperatures. The polymerisation reactions were followed by aromaticity enhancements, giving rise to higher coke yields.

ACKNOWLEDGMENTS

The authors thank Fundação de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG), Federação das Indústrias do Estado de Minas Gerais (FIEMG) and Instituto Evaldo Lodi (IEL) for financial support.