Isolation of aromatic compounds from a coal extract by semipreparative HPLC

Summary Two methyldibenzofuran isomers and a tetramethylnaphthalene isomer have been isolated from the organic extract of a Sakoa (southwest Madagascar) coal and were positively identified by IR spectroscopy. The isolation procedures were carried out on a semipreparative scale and included two to four normal-phase HPLC steps and a reversed-phase HPLC step. Reproducibility of the normal-phase fractionations on alumina was enhanced by an improved moisture-control system. Substantial enrichment of the compounds of interest was achieved in each step, as evidenced by capillary GC.