Process for the preparation of 5-nitro-1,4-naphthoquinone
AssigneeNippon Shokubai Kagaku Kogyo Co., Ltd.
InventorsHiroshi Koike, Akio Fukui, Yuji Ito, Takehiko Tanaka, Yukio Okuda
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Abstract
A process for the preparation of 5-nitro-1,4-naphthoquinone comprising nitrating 1,4-naphthoquinone under such a condition that the dehydrating value of sulfuric acid in the reaction mixture is at least 4 to selectively introduce a nitro group into the 5-position and pouring the reaction mixture into an aqueous medium to precipitate the product.
Claims16
A process for the preparation of 5-nitro-1, 4-naphthoquinone comprising nitrating 1,4-naphthoquinone with nitric acid in the presence of sulfuric acid at a temperature of -20.degree.C to +80.degree.C and under the condition that the weight ratio of the total amount of sulfuric acid to the total amount of water in the reaction system is at least 4 and adding the resulting reaction mixture to an aqueous medium to precipitate the product.
A process for the preparation of 5-nitro-1,4-naphthoquinone comprising nitrating 1,4-naphthoquinone at a temperature of 0.degree. to 60.degree.C by nitric acid in an amount of 0.8 to 7 moles per mole of 1,4-naphthoquinone in the presence of sulfuric acid in an amount of 2 to 30 times the weight of 1,4-naphthoquinone while keeping the weight ratio of the total amount of sulfuric acid to the total amount of water in the reaction system at a value of at least 6 and adding the reaction mixture thus obtained to an aqueous medium to precipitate the product at a temperature of 30.degree. to 70.degree.C.
Dependencies are inferred from the claim text.