Studies of Retrogressive Reactions in Direct Liquefaction

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions

“…Carboxyl functions have been implicated in the crosslinking of coals during at relatively low temperatures [30,31], and Solomon and coworkers [32] have been able to model the pyrolytic loss of solvent swelling by including one additional crosslink in the network for every CO 2 evolved. Moreover, pretreatments that have been found to be effective in promoting liquefaction have also shown a corresponding decrease in the early CO 2 evolution [33]. These results strongly suggest that carboxyl functions are involved in the low-temperature crosslinking of coals.…”

An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields. Final report

“…However, there is also considerable evidence to show that drylng has a detrimental effect on the liquefaction behavior of coals (Silver and Frazee 1985;Silver et al 1986; Serio et al 1990). Coals have both a physical and chemical structure, so it is conceivable that drying affects one, the other, or both of these structures.…”

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions. First annual report, April 1, 1991--March 31, 1992

“…Carboxylfunctionshave been implicated _nthe crosslinking of coals during at relatively low temperatures (Suuberg et al, 1985; Serio el a!, 1987), and Solomon and coworkers (Solomon et al, 1990) have been able to model the pyrolytic loss of solvent swelling by including one additional crosslink in the network for every CO2 evolved. Moreover, pretreatments that have been found to be effective in promoting liquefaction, have also shown a corresponding decrease in the early CO_ evolution (Serio et al, 1990). These results strongly suggest that carboxyi functions are involved in the low-temperature crosslinking of coals.…”