High temperature in situ H-1 NMR study of mesophase formation in pitches

J M Andresen, M M Maroto-Valer, S C Martin, S R Moinelo, C E Snape

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In-situ H-1 NMR has been used to follow the extent of mesophase development during isothermal heat-treatments at 470-480 degrees C for a petroleum pitch (Ashland A-240) and a selection of coal tar pitches. Two Gaussian signals with spin-spin relaxation times (T(2)s) of ca. 20 and 70 mu s have been identifed for mesophase with the fully rigid component (T-2 of 20 sis) only arising at mesophase contents above ca. 30%. The less rigid component ip only evident above ca.400 degrees C and is considered to be attributable to gel-like material observed previously by TEM with the rigid phase arising from mesophase spheres. The kinetics of mesophase development was very much feedstock dependent with the petroleum pitch giving first order kinetics while, in contrast, the coal tar pitches displayed more zero-order behaviour. Secondary QI formed by tow temeprature heat-treatment of coal tar pitch increased the rate of mesophase development, but high temperature treatments to reduce volatiles retarded formation.

Original languageEnglish
Title of host publicationProspects for Coal Science in the 21st Century
EditorsBQ Li, ZY Liu
Place of PublicationShanxi
PublisherShanxi Science & Technology Press
Pages669-672
Number of pages4
Volume1-2
ISBN (Print)7-5377-1650-4
Publication statusPublished - 1999
Event10th International Conference on Coal Science - TAIYUAN
Duration: 12 Sep 199917 Sep 1999

Conference

Conference10th International Conference on Coal Science
CityTAIYUAN
Period12/09/9917/09/99

Cite this

Andresen, J. M., Maroto-Valer, M. M., Martin, S. C., Moinelo, S. R., & Snape, C. E. (1999). High temperature in situ H-1 NMR study of mesophase formation in pitches. In BQ. Li, & ZY. Liu (Eds.), Prospects for Coal Science in the 21st Century (Vol. 1-2, pp. 669-672). Shanxi Science & Technology Press.