Constituents of high-boiling petroleum distillates. Part X. 1,2,7,8-Tetramethylfluorene and methylbenzo[a]fluorenes

Abstract

A hydrocarbon isolated from a fraction of a Kuwait mineral oil has been identified by synthesis as 1,2,7,8-tetramethylfluorene. A crystalline mixture of methylbenzo[a]fluorenes from an Oklahoma oil is shown by gas chromatography to contain at least six components, four of which have retention times coincident with those of the 1-, 3-, 4-, and 10-methyl isomers. Syntheses of 1-, 3-, and 4-methylbenzo[a]fluorene are described.