Modifications in the Separation of Fluorene and Fluorenone L h s t and G(,keI ~ t r s c r i l ~R ~procedure d for the i y n t h e i ~of tluorenonr trom fluorrnr.' l'hr synthesis involves an air midation of the h y h r arlwn fluurcnr to a ytllow.~&md ketune fluurenone. After the oaidatiun, the resulting mixture 01 the r e ~ c t a n hand pnnluvts are separated by either o h m vhromah~graphyur recrystallizariun. The purposeof this paper is to make certain modifications to improve the efficiency of the separation. According to Durst and Gokel, the separation of the fluorene and fluorenone mixture by column chromatography requires that a 0.5 g sample of the crystalline mixture he dissolved in 1.0 ml of cyclohexane. This solution should then be applied to a 10 g alumina column and eluted.' While dissolving the mixture in the solvent, we discovered that the fluorene hut not the fluorenone dissolved in the cyclohexane..We reasoned that the nonpolar solvent, cyclohexane, could only dissolve the less-polar compound, fluorene, and not the more-polar ketone, fluorenone. Subsequently, it was found that 1.0 ml of toluene, a slightly polar solvent, effectively dissolved 0.5 g of the mixture at raom temperature. Once the toluene solution was applied to the alumina column, the components of the mixture were eluted first with petroleum ether and seeand with diehloromethane. I t was also found that by using 12 g of alumina, the bands separated more efficiently with no significant loss of products. The eluted fractions were then dried. The residues were weighed and dissolved in enough dichloromethane to yield 5% solutions. Analysis of the fractions by comparative thin-layer chromatography using Silica Gel plates with fluorescent backing showed that the fluorenone fraction was free of any fluorene and vice versa. The solvent system for the TLC was 20% CH&B in hexane. and the R~factOIswere 0.9 for fluorene and 0.45 for fluorenone.2The eluted fractions were also analvzed , by a Per-kin-~lmer~ o d e23:H l lnfrarcd3pevtrophc,tomrtL.r. 'I.h~tluorrn~eluarrsshuwed a wrv pron
