SU462461A1 - Method of obtaining neozone-d and/or naphthol - Google Patents

Description

one

The invention relates to an improved method for the preparation of neozone-D and / or 2-naphthol, which is used as a starting material for the synthesis of tanning agents.

A known method for producing neo-D and / or 2-naphthol by reacting the sodium salt of 2-naphthalenesulfonic acid with aniline in the presence of a hydroxide and / or alkali metal salt at 200-400 ° C and vigorous stirring is carried out in a Vishnevsky autoclave.

However, by this method only neozon-D is obtained as the desired product, and 2-naphthol is contained in the final product as an impurity in amounts not exceeding a few percent.

The proposed method makes it possible to eliminate this drawback and to carry out the joint production of neozone-D with 2-naphtol and to regulate their ratio. In addition, the implementation of the method does not require devices with highly efficient mixing, since the method can be implemented in devices with a propeller stirrer. The combined preparation of neozone-D and 2-naphthol greatly simplifies the technological scheme for the preparation of these two products.

This is achieved by reacting the sodium salt of 2-naphthalenesulfonic acid with aniline in the presence of a hydroxide and / or an alkali metal salt.

continuous removal of the azeotropic mixture of aniline with the reaction water. At the same time, if the process is carried out at 200-270 ° C, neozone-D is predominantly obtained with a yield of 90-92%, and at 300-400 ° C, 2-naphthol is preferably obtained with a maximum output of 707 ÂB and the propeller mixer is loaded 2-naphthalenesulfonic acid, aniline, and also either a hydroxide and an alkali metal salt (for example, caustic soda and potash) or only a hydroxide (for example, caustic potassium) in a molar ratio of 1: 5-40: 1-2: 1 and heated at 200 -400 ° C in

0.5-40 hours. During the aging, the water formed as an aniline azeotrope with water is continuously distilled off. At the end of the exposure, excess aniline, used as

Claims (3)

The medium for creating mobility and homogeneity of the reaction mass is distilled and used for the next operation. Sodium naphtholate and sulfite are separated from the reaction mass with water and 2-naphthol is separated from the resulting solution in a known manner, and the remaining technical neo-D is dried and distilled in vacuo. Example}. 60 g (0.26 mol) of sodium salt of 2-naphthalenesulfonic acid, 1105 g (11.9 mol) of aniline and 20 g (0.5 mol) of caustic soda are heated in a 1.5 liter apparatus with a propeller stirrer at 300 ° C for 10 h with continuous removal of the reaction water from the apparatus. The rate of distillation of aniline azeotrope with water is 40 ml / h. At the end of the exposure, excess aniline is distilled off from the reaction mass, sulphite is washed on the filter and sodium naphtholate. 25 g of 2-naphthol are recovered from the filtrate in a known manner. The output of 2-naphthol on the loaded beta-salt 66%. The filter cake is dried to constant weight and 16 g of a technical product with neozone-D (L-phenyl-2 naphtylamine) content of 92% are obtained. The output of neozone-D on the loaded beta salt is 26%. Example 2. 60 g (0.26 mol) of beta-salt, 950 g (10.1 mol) of aniline, 20 g (0.5 mol) of caustic soda and 55 g (0.4 mol) of potash are heated at 310 ° C 4 h. The speed of distillation azeotropa 100 ml / h. After treating the reaction mass in the manner described, 19.2 g of technical neozone-D are obtained with a main substance content of 95% (32% yield) and 25.6 g of 2-naphthol (68% yield). Approx 3. 41.3 g (0.18 mol) of beta-salt, 900 g (9.7 mol) of aniline and 17.8 g (0.32 mol) of potassium hydroxide are heated at 310 ° C for 6 hours. Speed distillation azeotrope 100 ml / h. Neozon-D is obtained with a yield of 20% and 2-naphthol with a yield of 70%. Example 4. 45.9 g (0.2 mol) of beta-salt, 1000 g (10.8 mol) of aniline, 12 g (0.3 mol) of caustic soda and 41.4 g (0.3 mol) of potash are heated at 240 ° C for 8 hours. The speed of azeotrope distillation is 100 ml / h. Neozon-D is obtained with a yield of 90% and 2-naphthol with a yield of 6%. Example 5. 41.3 g (0.18 mol) of beta-salt, 1200 g (13 mol) of aniline, 17.8 g (0.32 mol) of caustic potash are heated at 240 ° C for 4 h. Azeotrope distillation speed 100 ml / h The output of neozone-D is 92%, 2-naphthol - 6%. Example 6. 41.3 g (0.18 mol) of beta-salt, 1200 g (13 mol) of aniline, 12 g (0.3 mol) of caustic soda and 41.4 g (0.3 mol) of potash are heated at 290 ° C 6 h. The speed of azeotrope distillation is 100 ml / h. The output of neozone-D is 43%, 2-naphthol - 45%. Claim 1. Method for preparing neozone-D and / or 2-naphthol by reacting sodium salt of 2-naphthalenesulfonic acid with aniline in the presence of hydroxide and / or alkali metal salt at 200-400 ° C, in order to simplify the process, the reaction carried out with the continuous removal of the azeotropic mixture of aniline with the reaction water. 2. A method according to claim 1, characterized in that, in order to predominantly obtain neozone-D, the process is carried out at 200-270 ° C. 3. The method according to claim 1, characterized in that, in order to predominantly obtain 2-naphthol, the process is carried out at 300-400 ° C.