Process for the manufacture of bis(benzot hiazylsulphene) amides
United States Patent Maison [451 Apr. 1, 1975 PROCESS FOR THE MANUFACTURE OF BIS( BENZOT HIAZYLSULPHENE)AMIDES Related US. Application Data Continuation of Ser. No. ll0,745, Jan. 28, 1971, abandoned.  
 Inventor:  
 Foreign Application Priority Data Jan. 30, 1970 France 70.0335l US. Cl 260/306.6 A, 260/4, 260/785 Int. Cl C07d 91/48 Field of Search 260/306.6 A  
 References Cited UNITED STATES PATENTS ll/l958 Conly 260/306.6 A  
 Primary Examiner-Richard J. Gallagher Attorney, Agent, or FirmStevens, Davis, Miller &amp; Mosher [5 7 ABSTRACT Bis-(benzothiazylsulphene)amides of formula:  
 where R is a hydrocarbon radical, are obtained by treating a benzothiazylsulpheneamide of formula:  
 with an organic acid anhydride having a structural formula which includes at least one ring, e.g., phthalic or maleic anhydride;  
 6 Claims, No Drawings ring can also originate from two carboxyl groups in an PROCESS FOR THE MANUFACTURE OF rather repidly and within a small volume which gives a BIS(BENZOT HIAZYLSULPHENDAMIDES high productivity for the apparatus. This is a continuation of application Ser. No. Reaction between reagents which are solid at the rell( ,745, filed Jan. 28, 1971, and now abandoned. action temperature can be improved by carrying out The present invention relates a new process for the 5 the process in the presence of a solvent which is inert manufa tur f bis-(benz hi zyl ulph ne)ami towards the reagents under the conditions employed.  
  Bls&#39;(bchzhthluzylsulphehe)hmldes have been Suitable solvents include hydrocarbons such as cycloscribed in Pat. Spec. NO. and are useful hexane benzene aliphatic petrols n heptane or halo- 21S flCCClCI&#39;EltOI&#39;S fOI&#39; thC vulcanisation Of natural OI syngenated solvents where the halogen atom is of low reacthC C C l0 tivity, such as carbon tetrachloride or chlorobeiizene. The Present lhvehtloh Provldes 11 lih&#39;oceSS the If the solvent boils at the temperature used, it will be Preparation of bls&#39;(behzhthlazylsulphehe)ahhdes of convenient to carry out the process so that the vapours general formula: of the solvent reflux.  
  A molar ratio of monosulpheneamide/anhydride group of about 2 is used. Generally, a slight excess of anhydride (for example up to about allows the I i yield relative to the more costly product, the monosulpheneamide, to be improved. Furthermore, this allows a final product almost free of monosulpheneamide to be obtained. The starting monosulpheneamide can contain up to 10% of impurities without disadvantage.  
  It is not essential for the reaction medium to be homogeneous to obtain the bis-(benzothiazylsulphene)amide. Furthermore, traces of water do not unfavourably affect either the yield or the quality of the product obtained.  
  l The crude reaction product, freed of solvent if used, 5 Sum can be used as such as an accelerator for the vulcanisation of rubber mixtures, because the impurities present are practically inert towards rubber and only behave as diluents. However, if desired, the greater part of the reaction by-products (acid amide, or amide and acid) can easily be removed, as can a possible excess of anhydridc, by a treatment with alkali. For this purpose, the crude reaction product can be subjected to the action of aqueous alkaline solution, e.g., an alkali metal hydroxide solution or an ammonia solution, at about 10 to 30C; the bis(benzothiazylsulphene)amide remains insoluble in this medium, whilst the other products present pass into solution.  
 in which the symbol R represents a hydrocarbon radical, by reaction of a benzothiazylsulpheneamide of general formula:  
 with an organic acid anhydride having a structural formula which includes at least one ring.  
  In the anhydridcs of cyclic formula, a ring can be bonded to the acyl group, for example in aromatic carboxylic acid anhydrides such as bcnzoie anhydride. The  
 intramolecular anhydride, such as anhydridcs of aliphatic dicarboxylic acids containg 4 to 6 carbon atoms (for example maleic, succinic or glutaric ai&#39;ihydrides). Condensed polycyclic anhydrides can also be used; these are intramolecular anh drides of aromatic car- I boxylic acids such as phthalic anhydride and pyronielh y phcne)amidcs obtained acmic unhwiridu cording to process of the invention show a h gh lt is preferred that R represent a linear or branched Smmgc f w h Posslhlc h &#34;ulchhlsmhm alkyl radical of l to 12 carbon atoms. such as methyl, Speeds wlth 8&#39; safety use, and p advantacthyL impmpyL goclyl or dummy], or a gyclm geo us mechanical properties (tensile strength and elonlk l d l i 5 to 6 ring carbm atoms Such as gation at break, and modulus at 300%) to the vulcanclopentyl or cyclohexyl. ISCd P u ts. i I  
 The reaction takes place in accordance with the fol- The Examples Whlch lOllOW Il u trate the Invention.  
 . 5O lowing equation:  
 L. coma where-CO-XCO- represents either a diacyl radi- EXAMPLE 1 cal or two monovalent cyclic acyl radicals. 82 g of phthalic anhydride (055 mol) and 264 g The reaction temperature depends on the reagents cyclnhcxylbenlothiazylsulpheneamide of 98% purity used. particularly their heat stability, their melting (repre enting 0.9? mol) are introduced cold into a point and their reactivity and, where a solvent is emmiXer equipped with a heating acket, and then stirred. ployed. their solubility. A suitable reaction tempera- The temperature of the mixture is raised to l00C and ture is generally between 35 and C, and preferamaintained at that temperature for 30 minutes; the bly between 60 and l l()C. If the process is carried out mass thickness, becomes pasty and then solidifies and in the absence of solvents, the reaction takes place crumbles.  
  The crumbled mass is cooled to 20C. The mixture obtained, which melts at between 120 and 140C, consists of excess phthalicanhydride; cyclohexylphthalamie acid and N-cyclohexyl-bis-(benzothiazylsulphene)amide. This mixture is treated with 1.1 litres of a normal aqueous sodium hydroxide solution for 2 hours at 20C. Filtration, washing and drying gives 202 g of cyc1ohexyl-bis (benzothiazylsulphene)amide, melting 132133C. The yield is 93.8% relative to the crude N-eyelohexylbenzothiazylsulpheneamide.  
  The impurities in the crude product for practical purposes do not cause any reduction in the activity of the purified product, as is shown by the comparative vulcanisation test described below:  
  The following mixing formulation (composition by weight) is used.  
 TABLE 1 Plasticiser (predominantly naphthenic oil.  
 &#39; marketed under the trademark NAPTOLEN) 5 Resin (diolclinc polymer marketed under the trademark ESCOREZ) Micro-crystalline wax (mixture of aliphatic I hydrocarbons) &#39;lrin ethyldihydroquinolinc polymer N-lsopropyl-N -phenyl-p-phenylenediaminc 1 Insoluble sulphur See N-Cyclohcx \&#39;l-his( benzothiazylsulphene )amide Table 11 The following results are obtained (Table 11).  
 EXAMPLE 3 82 g of phthalic anhydride (0.55 mol) and 238 g of t-butyl-benzothiazylsulpheneamide of 98% purity (representing 0.98 mol) are introduced cold into a mixer equipped with a heatingjecket and stirred. The temperature of the mixture is raised to 100C and maintained at that temperature for 1 hour. The mass initially thickens, becomes pasty and then solidifies and crumbles. The resulting mixture of phthalic anhydride, t-butylphthalamic acid and t-butyl-bis(benzothiazylsulphene)-amide is cooled to about 20C.  
  This mixture is treated with 1.1 litres of a normal aqueous sodium hydroxide solution for 2 hours at 20C.  
 The bis-(su1phene)amide is filtered off, washed and dried. 194 g of t-butyl-bis-(benzothiazylsulphene)amide, melting at 141C, is obtained in a yield of 96% relative to the crude t-butyl-benzothiazylsulpheneamide.  
 EXAMPLE 4 54 g of maleic anhydride (0.55 mol) and 264 g of cyclohexylbenzothiazylsulpheneamide of 96.8% purity (representing 0.968 mol) are introduced cold into a mixer equipped with a heating jacket, and stirred. The temperature of the mixture is raised to 60C and maintained at that temperature for minutes. The mass liquefies, becomes deep green and then pasty, and thereafter solidifies and crumbles.  
 TABLE 11 MOONEY Vulcanisation in a Cyclohexyl-bis(benzoscorching time press at 145C. thiazylsulphene)amide at 130C. optimum (in 300% modulus (minutes) minutes) (kg/cm) Product of Example 1, melting at 120-140C 47 41 89 (1.8 part) Product of Example 1 purified by an aqueous alkaline treatment 50 42 91 melting at l32133C.  
 (1 part) The products melting at 120-140C and at The resulting light beige mixture, melting at about 132133C show substantially the same safety against scorching as the chemically pure product obtained by recrystallisation from dimethylformamidc and melting at 136C. When 1 part ofthe pure product, melting at 136C, is used under the conditions of Table 11, the MOONEY scorching time is 51.5 minutes, indicating that the impurities in the product prepared according to the present process behave simply as inert diluents.  
 EXAMPLE 2 1,000 cm of carbon tetrachloride, 82 g of phthalic anhydride (0.55 mol) and 264 g of cyelohexylbenzothiazylsulpheneamide of 98% strength (0.98 mol) are introduced into a flask equipped with a stirring device.  
 The mixture is heated at the reflux temperature and consisting of excess maleic anhydride, cyclohexylmaleamic acid and N-cyclohexyl-bis(benzothiazylsulphene)amide, is cooled to 20C. This mixture is treated with 1.1 litres of a normal aqueous sodium hydroxide solution for 2 hours at 20C. Filtration, washing and drying yields 198 g of cyclohexyl-bis- (benzothiazylsulphene)amide melting at C. The yield is 92.4% relative to the crude N-cyclohexylbenzothiazylsulpheneamide.  
 EXAMPLE The procedure of Example 4, is repeated replacing i only of 92.9% purity, 195 g of cyclohexyl-bis-(benzothiazylsulphene)-amide, melting at l28-l30C, are obtained, representing a yield of 90.9% relative to the crude N-cyclohexylbenzothiazylsulpheneamide employed.  
 EXAMPLE 6 54 g of maleic anhydride (0.55 mol) and 238 g of tbutylbenzothiazylsulpheneamide of 92.2% purity (representing 0.922 mol) are introduced cold into a mixer equipped with a heatingjacket and stirred. The temperature of the mixture is raised to 100C and maintained at that temperature for /2 hour. The mass becomes liquid and then thickens, solidifies and crumbles. The resulting mixture of maleic anhydride, t-butyl-maleamic acid and t-butyl-bis-(benzothiazylsulphene)amide is cooled to about 20C.  
  This mixture is treated with 1.1 litres of a normal aqueous sodium hydroxide solution for 2 hours at 20C. The bis-(sulphene)amide is filtered off, washed and dried. 192 g of t-butyl-bis-(benzothiazylsulphene)amide, melting at l38l39C, are obtained, in a yield of 95.2% relative to the crude t-butyl-benzothiazylsulpheneamide employed.  
 I EXAMPLE 7 54 g of malcic anhydride (0.55 mol) and 224 g of isopropylbenzothiazylsulphencamidc of 94.3% purity (representing 0.943 mol) are introduced cold into a mixer equipped with a heating jacket and stirred. The temperature of the mixture is raised to 60C and main tained at that temperature for l hour 20 minutes. The mass liquefies and then cools and crumbles in the mixer.  
 The light beige mixture obtained, which consists of maleie anhydridc. isopropylmaleamic acid and isopropyl-bis-(benzothiazylsulphenei-amidc is cooled to 20C.  
 This mixture is treated with 1.1 litres of a normal aqueous sodium hydroxide solution at 20 for 2 hours.  
  Filtration. washing and drying yields 173 g of isopropyl-his-( benzothiazylsulphcne)amide melting at 100C, representing a yield of 89% relative to the crude N- isopropylbenzothiazylsulphcneamide employed.  
 EXAMPLE 8 If. in place of working at 60C as in Example 7, the process is carried out at 40C, all other aspects being the same, the duration of the reaction must be extended to 4 hours 10 minutes (in place of 1 hour minutes). After treatment with sodium hydroxide, 180 g of isopropyl-his-(benzothiazylsulphene)amidc, melting at 101C, are obtained, representing a yield of 93% relative to the crude N-isopropylbenzothiazylsulpheneamide (of 94.3% purity) employed.  
 EXAMPLE 9 60 g of pyromellitic anhydride (0.275 mol) and 264 g of cyclohexylbenzothiazylsulpheneamide of 98.1%  
 purity (0.98 mol) are introduced cold into a mixer equipped with a heating jacket, and stirred. The temperature of the mixture is raised to C and maintained at that temperature for 2 hours. The mass becomes pasty and then again hardens, whilst still remaining pasty. After cooling to 20C., it slowly solidifies.  
 This crude mixture is thereafter treated with 1.1 litres of a normal aqueous sodium hydroxide solution for 2 hours at 20C. Filtration, washing and drying yields 207 g of cyclohexyl-bis-(benzothiazylsulphene)amide, melting at l26127C. This represents a yield of 96.3% relative to the crude cyclohexylbenzothiazylsulpheneamide employed.  
 I claim:  
  1. Process for preparing a bis-(benzothiazylsulphene)amide of general formula:  
 in which R is alkyl of l to 12 carbon atoms, cyclopentyl or cyclohexyl,- wherein a benzothiazylsulphcncamide of general formula:  
 SNHR  
 is reacted with maleic anhydride, succinic anhydridc, glutaric anhydridc, phthalic anhydridc, or pyromellitic anhydride.  
  2. A process according to claim I wherein the molar ratio of benzothiazylsulpheneamidc to anhydride groups is substantially 2:1.  
  3. A process according to claim 1 wherein the reaction is carried out in the presence of an inert solvent.  
  4. A process according to claim 1 wherein the reaction product is treated with an aqueous alkaline solution and the insoluble bis-(benzothiazylsulphene)amide separated form the solution containing impurities.  
  S. A process according to claim 1 wherein a benzothiazylsulpheneamide in which R represents cyclohexyl, isopropyl or tert.-butyl is heated at 60l 10C in the presence of about V2 a molar proportion of phthalic anhydridc or malcic anhydride or about A of a molar proportion of pyromcllitic anhydride for about V2 to 2 hours.  
  6. A process according to claim 5 wherein the reaction product is washed with an aqueous sodium hydroxide solution at about 10 to 30C and the insoluble bis- (benzothiazylsulphenc)amide separated from the solution containing impurities.