Dichloro-3,6-fluorenone

A mixture of 5 g. (0.028 mole) of fluorenone (p. 163) and 6 g. (0.029 mole) of phosphorus pentachloride is heated to 150° and held at this temperature for 30 minutes. The cooled product is pressed on a porous plate to remove oily material and then recrystallized from petroleum ether. There is obtained a 70fo yield of the dichloro compound melting at 101.5-102.5°. 

The reaction enthalpies for the photo-reduction of ketones and azoalkanes in n,ji states by the model hydrogen donors methanol and dimethylamine have been calculated. These data, together with a consideration of excited-state electrophilicity and the antibonding character of transition states, have been used to rationalize the nucleophilic character of singlet n,ji excited azoalkanes and the electrophilic character of correspondingly excited ketones. A theoretical model for the photo-reduction of carbonyl compounds, based on the assumption that hydrogen transfer involves electron transfer followed by proton transfer, has been developed. The model was able to describe the available kinetic data for the photo-reduction of o-benzoquinones and fluorenone in the presence of para substituted iV,iV-dimethylanilines and those for the photo-reduction of p-chloro-anil and 2,6-dichloro-l,4-benzoquinones in the presence of polymethylben-zenes. The photochemical properties of the triplet ji, n state of 5,12-naph-... 

Alben (1980) chlorinated a coal-tar leachate that contained many polycyclic aromatic hydrocarbons and demonstrated that many hydrocarbons were significantly reduced in concentration. Oxygenated compounds, such as dibenzofuran (17), were formed, together with low concentrations of chlorinated and brominated derivatives of naphthalene and fluorene. Chlorinated polycyclic compounds have been demonstrated to occur in drinking water samples (Shiriashi et al., 1985), including mono-and dichloro derivatives of naphthalene, fluorene, dibenzofuran, phenanthrene, fluoranthene, and fluorenone (Figure 5.3). 

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