Benzene → Anthraquinone

Participants

Reaction Conditions

Reaction Steps

22.2 g of phthalic anhydride (0.15 mole) were charged into a stainless steel autoclave at ambient temperature with 10 cm3 of methylene chloride. The autoclave was cooled with liquid nitrogen. 30 g of HF (1.5 mole) and 102 g of BF3 (1.5 mole) were introduced. The temperature was brought to -40° C. and 12.9 g of benzene (0.165 mole) were introduced during 15 minutes. The temperature was maintained at -40° C. for one hour under 15 bars pressure, followed by decompression and degasification under vacuum to evaporate HF, BF3 and CH2Cl2 ; 10% caustic soda was then added to give a pH of 9. The solution was filtered, then acidified by addition of concentrated HCl. The O.B.B. acid precipitated in the form of very pure white crystals. The whole of the O.B.B. acid obtained was treated for 1 hour at 150° C. in 100% sulfuric acid. After cooling and dilution with water, 25.6 g of anthraquinone of 99.8% purity were obtained, i.e., an overall chemical yield of 82%.

Provenance & Evidence