CS242167B1 - Process for processing pitch-like substances from the production of N-cyclohexylbenzothiazole-2-sulfenamide - Google Patents

Abstract

The subject of the solution is the processing of resinous substances from the production of N-cyclohexylbenzthiazole-2-sulfenamide, which is used as an accelerator in the rubber industry. Resinous substances react with alkali metal hydroxide or alkaline earth metal hydroxide or oxide to release a cyclohexylamine aqueous layer, which is separated. After the reaction of resinous substances with alkaline earth metal hydroxide or oxide, the reaction mixture reacts with alkali metal silicate and the resinous substances bind to the resulting alkaline earth metal silicate, which is separated from the aqueous solution. The reaction preferably takes place at a temperature of 50 °C to the boiling point of the mixture.

Description

242167

The present invention provides a process for the treatment of non-reactive compounds from the manufacture of N-cyclohexylbenzothiazole-2-sulfenamide which is used in the rubber industry for the treatment of natural and synthetic rubbers as a safe delayed-action accelerator. N-Cyclohexylbenzthiazole-2-sulfenamide as the active ingredient of the product known under the trade name Sulfenax CB / K is produced by the procedures outlined in AO No. 4, No. 5, and U.S. Pat. 215179 and 225 046, which consist of reacting 2-mercap-tobenzothiazole with an excess of cyclohexylamine and subsequently oxidizing the resulting cyclohexyl-amine salt with an oxidizing agent such as sodium hypochlorite. The advantage of this process is that all by-products in the oxidation process by condensation with an oxidizing agent in excess of cyclohexylamine remain dissolved in cyclohexylamine and are separated from the resulting product by filtration. V čs. AO No. 221 005 is used to treat the recovered solutions after N-cyclohexylbenzothiazole-2-sulfenamide filtration. After the cyclohexylamine, which is returned to the production process, is distilled off, the by-products remain in the pitch, which remains unpleasant. In addition, some of the cyclohexylamine remains after the distillation in waste containers where it is chemically bound.

The aforementioned drawbacks are alleviated by the process of processing pitch-like substances produced by N-cyclohexylbenzthiazole-2-sulfenium, the principle of which is that the alkali metal hydroxide or alkaline earth metal oxide or hydroxide is reacted in the aqueous medium. the alkaline earth metal oxide or hydroxide or hydroxide is 1: 0.05 to 1: 3. The temperature during the reaction is between 50 ° C and the boiling point of the reaction mixture. The cyclohexylamine released by the reaction is separated from the residue in the aqueous solution. The aqueous solution may be cyclohexylamine obtained by conventional operations, for example by distillation or rectification.

After the reaction of the pitch-containing substances with the alkaline earth metal oxide or hydroxide, the alkali metal silicate is added to the reaction mixture. The molar ratio of alkali metal hydroxide or alkali metal oxide to alkali metal silicate is 0.3: 1 to 3: 1. The products of the hydrolysis of the smoky substances and the alkaline earth metal silicate are bound to the formed alkali metal silicate. cyclohexylamine can be obtained from the aqueous solution by distillation or rectification. The reaction yields alkaline earth metal silicate with surfactant residue residues, and in the resulting suspension, a product is obtained by filtration, in which the remaining salt is bound to the surface of the surface in a solid manner such that it is not reversible. The product obtained has a powder-like character after drying.

In particular, cyclohexyl amine, which is a valuable raw material, can be obtained by the process according to the invention. In addition, when using metal hydroxide or metal oxide with subsequent precipitation with an aqueous alkali metal silicate solution, a good filterable precipitate is obtained with the possibility of isolating the solid product, the properties of which are much more advantageous from the environmental and handling point of view. Also, the use of this material in the building industry, respectively, is contemplated. in other industry industries. EXAMPLE 1 70 g of technical calcium oxide are mixed with 150 ml of water and 50 g of organic pitch-containing N-cyclohexylbenzothiazole-2-sulfenamide are added to the mixture at 95 DEG. After homogenization at the boiling point of the mixture and subsequent hydrolysis of the effluents, 50 g of an aqueous sodium silicate solution (aqueous glass) and 30 ml of water are added to the mixture. After cooling the mixture and filtering off the precipitate, a non-sticky consistency solid and a filtrate containing 8128 mg / l of cyclohexylamine are obtained. Example 2

However, instead of 70 grams of technical calcium oxide, 93 grams of technical calcium hydroxide is used and a waste pitch from the production of N-cyclohexylbenzothiazole-2-sulfenamide is added to the cold lime milk to a temperature of 120 ° C. After hydrolysis of the pitch and subsequent adsorption of the decomposition product with the silicate precipitate, a filtrate containing 6243 mg / l of cyclohexylamine was obtained by extraction of the solid product. Example 3

The procedure of Example 1 is followed, except that after the hydrolysis of the effluent, the aqueous layer containing 7250 mg / l of cyclohexylamine is separated prior to the addition of the aqueous sodium silicate solution. The precipitation of calcium silicate with adsorbed residues of the salt and filtration of the precipitate in the second filtrate contained 87 mg / l of cyclohexylamine. Example 4

The procedure of Example 1 is followed but 45 g of sodium hydroxide is used instead of calcium oxide. After the reaction, the aqueous layer contains 8050 mg / l of cyclohexylamine separated from the reaction mixture.

Claims (2)

The invention can be used to produce N-cyclohexylbenzothiazole-2-sulfenamide which is used as a vulcanization accelerator. According to the invention, cyclohexyl-amine is obtained which can be regenerated and returned to the production process. At the same time, an inert, solid and good handled waste product is obtained with the possibility of further use, e.g. in the construction industry. OBJECT CLAIMS 1. A process for the treatment of pitch-like substances in the manufacture of N-cyclohexylbenzthiazole-2-sulfenamide, characterized in that in the aqueous medium, the alkali metal hydroxide or alkali earth metal hydroxide is used to effect the pitch. the alkali metal or alkaline earth metal oxide or hydroxide is 1: 0.05 to 1: 3, the temperature ranges from 50 ° C to the boiling point of the reaction mixture, wherein the water-released cyclohexylamine solution is separated from the residue . YES 2. A process as claimed in claim 1, wherein, after the reaction of the pitch-containing substances with the oxide or the alkaline earth metal hydroxide, the alkali metal silicate is added to the reaction mixture, the molar ratio of the alkali metal hydroxide or metal oxide to the alkali metal silicate being 0.3: 1. to 3: 1, and after the hydrolyzed pitch-based hydrolysis products are formed on the alkaline earth metal silicate formed, the alkaline earth silicate is separated from the aqueous solution.