SK53393A3 - Method of isolating of n-cyclohexylbenzothiazolyl- 2-sulfenamide from suspension of reaction mixture - Google Patents

Abstract

N-cyclohexylbenzothiazolyl-2-sulfenadmide is isolated of the reaction mixture suspension created as a result of the reaction of 2-merkaptobenzothiazole with a molar excess of cyclohexylamine and sodium hypochlorite with the use of the pressure or vacuum filtration so that, the phase closed to the separation of the mother's solutions of N-cyclohexylbenzothiazolyl-2-sulfenamide is provided after the phase closed to the filtration barrier regeneration, with the use of concentrated cyclohexamime in the quantity of at least 10 l/m2 has been completed, however the suitable quantity is closed to the value of 50 l/m2.

Description

Last blast techniques

The invention relates to a process for the isolation of N-cyclohexylbenzothiazolyl-2-sulfenamide from the reaction mixture suspension.

BACKGROUND OF THE INVENTION

In principle, the older processes for the preparation of N-cyclohexylbenzothiazoles of 1-2-sulfenamide are based on sodium, calcium, and calcium, respectively. ammonium salts of 2-mercaptobenzothiazole acidified with mineral acid and are described in CS 114 693, U.S. Pat. Nos. 2,191,657,226B 467,2762

14 and DE 855 564 and DAS 1 940 364. More recent and more modern processes for the preparation of N-cyclohexylbenzothiazole-2-sulfenamide are based directly on 2-mercaptobenzothiazole as a melt of the high pressure reaction product of aniline, carbon disulphide and sulfur and described in A0 215 179; A0 225 046, A0 260 786, A0 263 560, in GB 2 080 294-B and DE 3 127 193. The production of N-cyclohexyl-1-benzothiazoles 1-2-sulfenamide is its separation from the reaction mixture, which is normally by decanting, centrifuging, resp. filtration. Filter on vacuum and pressure filters. A disadvantage of said separation of N-cyclohexylbenzothiazolyl-2-sulfenamide from the reaction mixture is that the filter baffles are relatively quickly clogged with fine particles of N-cyclohexylbenzothiazolyl-2-sulfenamide alone, forming hardened deposits on them, thereby increasing their hydraulic resistance and increasing their hydraulic resistance. filtration rate.

SUMMARY OF THE INVENTION

These drawbacks are largely eliminated by the process of isolating N-cyclohexylbenzothiazolyl-2-sulfenamide from the reaction mixture suspension obtained by reacting 2-mercaptobenzothiazole with a molar excess of cyclohexylamine and sodium hypochlorite by pressure filtration or vacuum filtration, which consists in the separation of cyklohexylbenzotiazoly1-2-sulfenamide is prefixed regeneration phase of the filter webs concentrated cyklohexy1amínom of not less than 10 l / ^m is preferably 50 l / m ^=.

η

An advantage of the process for isolating N-cyclohexylbenzothiazolyl-2-sulfenamide from the reaction mixture slurry of the present invention is that the hydraulic resistance of the filter barrier used to separate N-cyclohexylbenzothiazole-2-sulfenamide is kept constant and the filtration rate is not reduced.

DETAILED DESCRIPTION OF THE INVENTION

Example 1 «f

7 490 kg of the reaction mixture are metered into a pressure filter.

obtained by the reaction of 2-mercaptobenzothiazole as a melt of the crude product of the high pressure reaction of aniline, carbon disulphide and sulfur with cyclohexylamine and sodium hypochlorite according to A0 263 560 containing N-cyclohexyl 1 benzothiazoles 1-2-sulphenamide in an amount of 15.1.7.

%, organic phase in an amount of 19.5 7. and an aqueous phase of 65.4% by weight. and cooled to 20 ° C. The heterogeneous mixture is filtered under an absolute nitrogen pressure of 250 kPa by first filtering out the lower aqueous phase and then the upper organic phase. After 205 minutes the filtration of the mother liquors is complete and a filter cake containing 79.8 7-N-cyclohexyl 1-benzothiazoles 1-2-sulfenamide remains on the filter septum.

Example 2

A pressure filter, in which three filtration steps were carried out for 30 hours according to Example 1, was charged and then filtered with 7 490 kg of the reaction mixture of the same quality and procedure as in Example 1. After 335 minutes the filtration of the mother liquors is complete and a filter cake containing 78.6% of the 7-N-cyclohexylbenzothiazol-1-yl-2-sulfenamide remains on the filter bed.

Example 3 (preferred object of the invention)

According to the invention, for example, a pressure filter in which, according to Example 2 and Example 2, four filtration operations have been carried out over a period of 40 hours, is concentrated cyclohexyl amine having an active compound content of 98.1 X in an amount of 10 liters per m. After standing for three minutes, the solution is drained into a reaction mixture ready for separation. In the next step, 7,490 kg of the reaction mixture of the same quality and procedure as in Examples 1 and 3 are metered in and then filtered. 2. After 202 minutes, the mother liquor filtration is complete and a filter cake containing 79.7% of N-cyclohexylbenzothiazolyl-2-sulfenamide remains on the filter.

Example 4

A continuously working vacuum filter is charged with the reaction mixture obtained by reacting 2-mercaptobenzothiazole as a melt of the crude high pressure reaction product of aniline, carbon disulphide and sulfur with cyclohexylamine and sodium hypochlorite according to AO 225 046, containing 14.6% by weight. N-cyclohexylbenzothiazolyl-2-sulfenamide, * 20.5% by weight. organic phase and 64.9 X masses. water phase. Hetero!

the gene mixture is filtered at 20 ° C and absolute pressure downstream of a 20 kPa filter. The hourly performance of the vacuum filter is gradually reduced from 321 kg / h at the start of filtration due to fouling of the filter fabric, so that 10,000 kg of reaction mixture at the desired N-cyclohexylbenzothiazole-2-sulfenamide content in the filter cake is 82-84%. is filtered off after 45 hours of continuous operation and a further 10,000 kg of reaction mixture after 66 hours of continuous operation.

Example 5 (preferred object of the invention)

A vacuum filter in which 20,000 kg / h of the reaction mixture was continuously filtered over 111 hours over a period of 111 hours was charged with concentrated cyclohexyl amine containing an active compound of 98.1 X in an amount of 50 liters per 1 m ⁼ filter baffle. After standing for three minutes, the solution is drained into a reaction mixture ready for separation. The next step is to continuously filter the reaction mixture _{and the} mixture of the same quality and procedure as in Example 4. The 10,000 kg suspension of the reaction mixture is filtered off after 40 hours, the contents being. The N-cyclohexylbenzothiazolyl-2-sulphenamide in the filter cake ranges from 82 to 84% by weight.

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Industrial usability f

The N-cyclohexylbenzothiazolyl-2-sulfenamide isolated from the slurry of the reaction mixture by the process of the invention is useful in the chemical industry.

Claims (1)

PATENT CLAIMS A process for the isolation of N-cyclohexylbenzothiazolyl-2-sulfenamide from a reaction mixture suspension obtained by reacting 2-mercaptobenzothiazole with a molar excess of cyclohexylamine and sodium hypochlorite by pressure or vacuum filtration, characterized in that the phase separating the mother liquors from N-cyclohexylbenzothiazole the regeneration of the filter prefixed FATA concentrated cyklohexy1amínom webs in an amount of at least 10 l / ^m is preferably 50 l / m =.