The preparation is divided into three steps. First, oleic acid is used to prepare oleoyl chloride, and then p-aminobenzene ether is used to prepare o-methoxyaminobenzenesulfonic acid. Finally, the two undergo acylation reaction.
Preparation of oleyl chloride The oleic acid is sucked into the reaction pot, and phosphorus trichloride is slowly added under stirring. The feeding ratio of the two is 0.8: 1 (molar ratio). In the process of dropping phosphorus trichloride, the reaction temperature is controlled at 25~30 ℃, and the temperature is gradually increased to 55 ℃ after dropping. Heat preservation reaction for 4 hours, stop stirring. Let stand for 3 hours. The lower phosphorous acid mixture is separated. The upper layer is crude oleyl chloride (I).
Preparation of o-methoxym-aminobenzene sulfonic acid 20% fuming sulfuric acid is added into a sulfonating pot, stirred, and p-aminoanisole is added in batches at 25~30 ℃. After adding, heat preservation reaction for 4 hours, add water to the dilution pot after reaching the end point, and press the sulfonated product to dilute it, stir below 70 ℃ for half an hour, after the solution is brown, cool and filter, and the filter cake is the finished product (II).
Preparation of m-oleoyamido-o-methoxybenzenesulfonate Sodium (I) and (II) are put into a reaction kettle, heated and refluxed for two hours, cooled to 25~30 ℃, and neutralized with alkali to pH 7~8, and the reaction is over. Cooling crystallization. The mother liquor is filtered out and then concentrated and crystallized. The two crystallizes are combined together and dried to obtain the finished product.