RESORCINOL, RESORCIN, 1:3 dihy droxy benzene, C41-14(OH),, is formed by the fusion of certain resins or gums with caustic alkalis. Aromatic compounds containing two side chains, e.g., benzene chlorsulphonic acids, benzene disulphonic acids and halogen phenols, will also yield resorcin when fused with caustic alkalis. On a commercial scale resorcin is pre pared by gradually heating a mixture of dry meta sodium benzene disulphonate and caustic soda. The mast is stirred during fusion, and the temperature is not allowed to go above 275° C. The product is treated with much water, acidified with hydrochloric acid, ex tracted with ether or benzene and finally puri fied by distillation and recrystallization from benzene.
Resorcin is a colorless, crystalline compound, with a melting point of 118° C., and a boiling point of 276.5° C. It is somewhat volatile with steam and dissolves readily in water, alcohol, ether and glycerine. Its aqueous solution re acts with bromine water to give a precipitate of tribromresorcin. On exposure to light and air it acquires a brown tint, due probably to the presence of moisture and traces of iron.
• Resorcin is extensively employed in the manufacture of synthetic dyes. Heated with
phthalic anhydride and a dehydrating agent it condenses into fluorescein, and from the latter may be obtained cosine, erythrosine, spirit cosine, cosine S, cosine BN, erythrosine G, spirit cyansosine, rose bengal, oriental yellow, etc. With phthalic anhydride, in the presence of benzyl . chloride and sulphuric acid, resorcin condenses into chrysoline — the important silk dye. With diazoxylene and dMzosulphanilic acid it forms resorcin brown. Resorcin is also employed for the preparation of tropaeofine 0, isodiphenyl black, lacmoid, Hessian brown RB, Kongo brown •G, fast green 0, Iris blue, Sudan G, etc.
On account of its antiseptic properties resorcin in water solution has been recom mended as a wash for diseased stomachs, in the treatment of skin diseases, in hay fever, nasal catarrh, chronic eczema and intestinal catarrh; but recent experimenters claim that the em ployment of resorcin in large doses will usually develop symptoms similar to those of alcoholic Poisoning.
V. S. Brumsnnair, Lehigh University.