Peter H. Given

TL;DR: In this paper, it was shown that there are two (or possibly three) populations of protons in coal, which exhibit appreciably different free induction decay times and hence have quite different levels of rotational mobility.

Abstract: Publisher Summary It is the geoscience of coals, that is, their geochemistry of origin and postburial geological history, that suggests that coals are a very diverse set of materials. This chapter discusses the relations between the chemistry of coal macerals and reviews the biochemistry of their precursors and the biological markers in coals that are indicative of their origins. The content of carboxyl groups in coals is commonly determined by an ion-exchange reaction with barium acetate. Values of 1–4 milliequivalents per gram have been found for lignites and lower-rank subbituminous coals—decreasing with increasing rank and essentially zero for coals of higher rank—except that HVC coals of the Rocky Mountain province may contain some carboxyl. The cations in the carboxylates of low-rank coals can give rise to calcite deposits in liquefaction reactors, can promote liquefaction, and can give rise to catalysts for the gasification of lignite chars.

TL;DR: In this article, the conversion of 104 high volatile bituminous coals at 400 °C with tetralin has been determined in duplicate with the aid of a new reactor system.

TL;DR: In this paper, a comparison of the liquefaction behaviour of two lithotypes from a Kentucky bituminous coal indicated that in this process pseudovitrinite is a reactive maceral.

TL;DR: The liquefaction behavior of a number of vitrinite-rich coals has been determined in batch autoclaves at temperatures of 385-425 °C and pressures of about 8.6 MPa (85 atm) of hydrogen.