Sepn. of 1,4- naptho quinone from phthalic acid anhydride - by heating in presence of 1,4,5a,9a-tetrahydro anthraquinone (BE031276)

摘要

The sepn. of 1,4-naphthoquinone from phthalic acid anhydride comprises treating the phthalic acid anhydride contg. the 1,4-naphthoquinone at 200-300 degrees C in the presence of 1,4,5a,9a-tetrahydroanthraquinone (I). The process is continuous and almost no corrosion problems arise. Phthalic acid anhydride of 99.7-99.5% purity is recovered from the prod. of the heat treatment, e.g. by distillation. (I) is used in amts. of 0.3-3 mol, esp. 0.8-1.5 mol/mol. 1,4-naphthoquinone, the heat treatment is pref. effected at 240-260 degrees C for 1/2-10 hrs. esp. 2-4 hrs. in the absence of molecular O2.