FR2486527A1 - PROCESS FOR THE PREPARATION OF N-CYCLOHEXYLBENZOTHIAZOLE-2-SULFENAMIDE - Google Patents

Abstract

METHOD OF PREPARING N-CYCLOHEXYLBENZOTHIAZOLE-2-SULFENAMIDE. THE PROCESS CONSTITUTES FIRST REACTING 2-MERCAPTOBENZOTHIAZOLE ON AN EXCESS OF CYCLOHEXYLAMINE AND THEN OXIDIZING THE CYCLOHEXYLAMINE SALT SOLUTION BY MEANS OF OXIDIZING, FOR EXAMPLE OF THE TYPE OF HYPOODCHLORITE. THE BY-PRODUCTS OF OXIDATION ARE REMOVED BY FILTRATION. 2-MERCAPTOBENZOTHIAZOLE MAY BE USED IN THE FORM OF THE CRUDE PRODUCT FORMED BY THE HIGH PRESSURE REACTION OF ANILINE, CARBON DISULPHIDE AND SULFUR.

Description

i

  The invention relates to the process for the preparation of N-cy-

  clohexylbenzothiazole-2-sulphenamide by reaction of 2-mercapto

  tobenzothiazole, cyclohexylamine and an oxidant. We

  use N-cyclohexylbenzothiazole-2-sulphenamide as an

  lerator sQr in rubber vulcanization.

  N-cyclohexylbenzothiazole is usually

  2-sulfenamide by oxidizing the cyclohexylamine salt of 2-mer

  captobenzothiazole with a solution of sodium hypochlorite or hydrogen peroxide:

C - SH NH2 - O CSNH - + H2

  The cyclohexylamine salt of 2-mercaptobenzene can be prepared

  zothiazole starting from the sodium, calcium or ammo-

  minium. 2-mercaptobenzothiazole is obtained in the form of these salts during the purification of the crude 2-mercaptobenzothiazole melt. The process for the preparation of the sodium salt is described in CS 114 693, US Pat. No. 2,191,657, 2,258,467 and 2,762,814, DE 855,564, DE-AS 1,940,364, US Pat. GB 642,597, 665,668, 1,106,577, that of the calcium salt in CS 113,006, DE-AS 1,940,364 and that of ammonium salt in CS 184,052,

  The principle of all these processes is the same. At the solution

  2-mercaptobenzothiazole salt in question, the prescribed amount of cyclohexylamine is added and the solution or suspension of the cyclohexylamine salt of 2-mercaptobenzothiazole is treated with a suitable oxidant, and

  obtained. The preparation of the sulfenamides directly in

  both amine salt of 2-mercaptobenzothiazole is the subject of a series of documents, US Patents 2,339,002, 2,772,279 and 3,144,652, GB 452,044, 655,668, 1,106,577, 519 617 and 1,289,407, DE 615,580, DE-AS 2,056,762, FR 852,118, R 950,693 and 1,549,002,

  patent applications JA 74 110 664 and 74 134 674.

  The processes mentioned in many cases have significant defects. The mineral bases used break as salts in the waste water, when salt is used

  of 2-mercaptobenzothiazole calcium is obtained as

  Calcium sludge containing impurities is removed and acidic insoluble calcium compounds are to be removed by acid washing. When starting from ammonium salt, the conditions that must be fulfilled by the manufacturing facility

are stricter.

  The sulphenamides which are prepared starting from the sodium salt do not have the required quality and that is why they are purified (see for example the patent FR 2 056 749, DE-AS 1 940 365, the patents GB 756,464 and 2,762,814), which leads to an increase in losses and the quantity of wastewater. It has now been found that high purity Ncyclohexylbenzothiazole-2-sulfenamide can be prepared by

  the process of reacting 2-mercaptobenzothiazole

  zole, cyclohexylamine and sodium hypochlorite.

  The essence of the invention lies in the fact that the 2-mercaptobenzothiazole is first reacted with an excess of cyclohexylamine, which represents 1.5 to 5 moles and advantageously 2.5 moles of cyclohexylamine per mode. of 2-mercaptobenzothiazole and then the solution of the cyclohexylamine salt of 2-mercaptobenzothiazole, thus prepared, is oxidized at a temperature of 20 ° to 20 ° C.

   C, advantageously 45.degree. C. and which is filtered off

  oxidation by-products. 2-mercaptobenzothiazole can enter the reaction as a crude reaction product which is formed when aniline, disulfide decarbon and sulfur are reacted under high pressure.

  product being used in a state free of volatile fractions.

  them or without prior purification.

  The process according to the invention guarantees a high yield

  and high purity of N-cyclohexylbenzothiazole-2-sulfoxide

  the process being simplified to a minimum and the preparation

  the cyclohexylamine salt of 2-mercaptobenzothiazole and its oxidation taking place in a single step. The advantage of

  The new process of preparation also lies in a reduction

  significant reduction in waste and waste water, which has

  a particular importance for ecology.

  The process for the preparation of N-cyclohexylbenzothiazole

  2-sulfenamide according to the invention is illustrated but not limited

by the following examples.

EXAMPLE 1

  In a 500 ml four-neck flask equipped with a fast stirrer, a thermometer, a reflux condenser

  and a dropping funnel, 118.8 g of cyclohe-

  50% xylamine (0.6 mole) and 34.8 g of 2-mercaptobenzothiazo-

  the 96% technique (0.2 mole). By mixing, the contents of the flask are heated to 85 ° C. and a salt solution is obtained.

  cyclohexylamine and 2-mercaptobenzothiazole which are

  It is then cooled to 45 ° C. By the funnel, 110 ml of sodium hypochlorite solution (16.7 g Ci per 100 ml) are added over a period of 60 minutes in a uniform stream. After a

  cooling, the temperature is maintained between 42 and 45 C.

  Once about 3/4 of the volume of solu-

  sodium hypochlorite, a crystalline product begins

  to separate from the reaction mixture. After the end of

  the mixture is allowed to react again for 30 minutes,

  then it is cooled to 20 ° C. The product is filtered off

  crystalline solution and washed on the filter with 1000 ml of 10% cyclohexylamine and then with 700 ml of water. The wet product is dried to constant weight. The yield is

  48.2 g, ie 91.2% of the theoretical amount of N-cyclohexyl-

  benzothiazole-2-sulfenamide. Melting point 101.5 at 102 ° C. Content of sulfenamide 99.7% (by mass)

  Insoluble residue 0.14% (by mass).

  The mother liquor and the first washing water are combined

  (two-phase system) and distilled under normal pressure.

  male of 0.1 MPa. 94.4 g of the azeotropic mixture of cyclohexylamine and water are obtained, which is recycled to the process after being completed with fresh cyclohexylamine. The

  yield calculated on the amount of cyclohexyl

  amine, represents 94.2% of the theoretical yield.

EXAMPLE 2

  The process of Example 1 is applied but using 79.2 g (0.4 mole) of 50% cyclohexylamine. 48.6 g of product (91.9% of theoretical yield) with a melting point of 100 to 102 ° C. are isolated. Sulfenamide content 98.2% (by weight),

  insoluble residue 0.25% (by mass).

EXAMPLE 3

  The process of Example 1 is applied but using g (1.0 mole) of 50% cyclohexylamine. 45.1 g of product (85.3% of the theoretical yield) having a melting point of 102 ° C. are isolated; content of sulfenamide 99.9% (by mass),

insoluble 0.1% (by mass).

EXAMPLE 4

  The procedure of Example 1 is applied but the temperature during the addition of sodium hypochlorite solution is 30 ° C. 47.2 g of product (98.2% of the theoretical yield) having a melting point are isolated. from 99 to 101 C; sulphenamide content 98.9% (by mass), insoluble residue 0.9% (in

mass). -

EXAMPLE 5

  The procedure of Example 1 is applied, but the temperature during the addition of sodium hypochlorite solution is 70 ° C. 46.2 g of product (80.55% of the theoretical yield) having a melting point are isolated. from 101.5 to 102 C; sulphenamide content 99.5% (by mass), insoluble residue 0,15%

(en masse)

EXAMPLE 6

  The procedure of Example 1 is applied, but 36.3 g of crude product at 92.0% given by the high reaction is used.

  pressure of aniline, carbon disulfide and sulfur.

  The yield is 48.0 g (90.8% of theoretical yield) of product having a melting point of 101 to 103.4 ° C; sulfenamide content 99.3% (by mass); insoluble residue 0.14% (by mass).

EXAMPLE 7

  The procedure of Example 1 is applied, but 38.8 g of 86.3% crude product given by the high reaction are used.

  pressure of aniline, carbon disulfide and sulfur.

  The yield is 46.4 g (87.7% of theoretical yield) of product having a melting point of 100 to 102 ° C; sulfenamide content 98.8% (by weight); insoluble residue 0.15%

(en masse)

EXAMPLE 8

  The procedure of Example 1 is applied but 102.5 ml of sodium hypochlorite (16.7 g of Cl-per 100 ml) is used for the oxidation. The yield is 45.3 g (85.7% of the theoretical yield) of product, mp 100 to 101 ° C., sulfenamide content 99.8% (by weight), insoluble residue

17% (by mass).

EXAMPLE 9

  The method of Example 1 is applied, but instead of sodium hypochlorite, 184 g of 5% hydrogen peroxide are introduced into the reaction as an oxidant. 46.1 g (87.1% of the theoretical yield) of product having a melting point of 101 to 102 ° C are obtained; content of 99% mlfenamide

  (en masse), insoluble residue 0.13% (by mass).

EXAMPLE 10

  The process of Example 6 is applied but 184 g of 5% hydrogen peroxide are used for the oxidation. The yield is 46.0 g (87.0% of theoretical yield) of product having a melting point of 101 to 103 C; sulfenamide content 99.2% (by mass), insoluble residue 0.10% (by mass).

EXAMPLE 11

  The method of Example 7 is applied but 184 g of 5% hydrogen peroxide are used for the oxidation. The yield is 44.9 g (84.9% of theoretical yield) of product having a melting point of 100 to 102 ° C; sulfenamide content 99.0% (by mass), insoluble residue 0.10% (by mass).

Claims (2)

  A process for preparing N-cyclohexylbenzothiazole-2-sulfenamide of the formula: NC - S - NH- I   by reaction of 2-mercaptobenzothiazole, cyclohexylamine and an oxidant, characterized in that the 2-mercaptobenzothiazole is first reacted with an excess of cyclohexylamine, ie 1.5 to 5 moles and advantageously   2.5 moles of cyclohexylamine by 2-mercaptobenzothiazine   zole, that the solution of the cyclohexyl salt   amine and 2-mercaptobenzothiazole, thus obtained, by means of sodium hypochlorite or hydrogen peroxide, at a temperature of 20 to 70 ° C., advantageously of 45 ° C., and   eliminates by filtration the byproducts of the oxidation.   2. Method according to claim 1, characterized by   that 2-mercaptobenzoate is introduced into the reaction   thiazole in the form of the crude product given by the reaction of aniline, carbon disulfide and sulfur, in the state stripped of volatile fractions by gas bubbling   inert or without priorpurification.