Chloroethane → 2-Naphthalenesulfonic acid, 5-amino-6-ethoxy-

Participants

Reaction Conditions

Reaction Steps

98.1 g of 1-acetamino-2-hydroxy-naphthalene-6-sulphonic acid (71.7% pure=50.4 g of 100% pure=0.25 mol), prepared according to Example 4, are introduced into a 1.3 l autoclave. 34.6 g (0.25 mol) of potassium carbonate suspended in 500 ml of ethanol are added thereto. After heating the mixture to 120° C., 115 ml of 2 N potassium hydroxide solution and 54 ml (74 g=0.75 mol) of ethyl chloride are simultaneously pumped in. The reaction mixture is allowed to cool somewhat, the salt residue is filtered off and, after adding 100 g of water, 460 g of ethanol (water-containing) are distilled off from the filtrate. 50 ml of 50% strength sodium hydroxide solution are added dropwise to the mixture at a temperature of 98° C. After 2 hours, the reaction mixture is cooled to room temperature and the product which has precipitated is filtered off and washed with 100 ml of saturated sodium chloride solution. After filtering off and drying, 76.1 g of 1-amino-2-ethoxy-naphthalene-6-sulphonic acid (78.3% pure=60.0 g of 100% pure=90% of theory, relative to 1-acetamino-2-hydroxy-naphthalene-6-sulphonic acid, or 69.4% of theory, relative to 2-hydroxy-naphthalene-6-sulphonic acid) are obtained.

Provenance & Evidence