The origin of aliphatic hydrocarbons in brown coal liquefaction: Reactions of a model acid, alcohol and ester

Abstract A model long-chain alcohol ( n -C 22 ), carboxylic acid ( n -C 20 ) and ester ( n -C 20 + n -C 22 ) have been reacted under coal liquefaction conditions at 320 and 405°C with both hydrogen and carbon monoxide-water as reducing systems. The products of these reactions were characterized by g.c., g.c.-m.s. and mass spectroscopy. In addition to materials with the same carbon number as the starting compounds, lower-molecular-weight materials arising from fragmentation and higher-molecular-weight compounds arising from radical recombination reactions were detected. Reactions with CO-H 2 O gave different product distributions from reactions with H 2 -SnO 2 and H 2 -tetralin, and these differences have been correlated with differences observed in reactions of low-rank coals. Reactions of eicosanoic (C 20) ) acid with hydrogen at temperatures from 320 to 415°C showed an unexpected formation of the ester CH 3 (CH 2 ) 18 CO 2 (CH 2 ) 19 CH 3 , especially for H 2 -SnO 2 reactions at 365°C.