To explore the feasibility of extracting aromatic acid products from oxidizing coal

two aromatic acids

trimellitic and[1

1'-biphenyl]-2

2'-dicarboxylic acid

were selected as the solutes

and the extraction equilibrium of the acids were studied with 1-octanol

50% tributyl phosphate(TBP)in kerosene

and 10% trialkylphosphine oxide (TRPO) in kerosene.The results showed that the degree of extraction of [1

1'-biphenyl]-2

2'-dicarboxylic acid was larger than that of trimellitic acid for all of the solvent

and the extraction capacity with TRPO is more effective than the one with TBP.The extraction behavior of aromatic polyacid is different from that of carboxylic acid

and the reactive extraction function of aromatic acids with TBP and TRPO is not as effective as that of carboxylic acid. 1-octanol could be used to remove[1

1'-biphenyl]-2

2'-dicarboxylic acid from the mixture of trimellitic acid and [1

1'-biphenyl]-2

2'-dicarboxylic acid.Because the weak hydrogen bond association exists between ——OH in 1-octanol and ——COOH in aromatic acid

the extractive selectivity of [1

1'-biphenyl]-2

2'-dicarboxylic to trimellitic acid depends on the stoichiometric ratio.