Mixtures of sulfurous triazine compounds
The invention is relates to mixtures of sulfurous triazine compounds and methods of their preparation. 
     BACKGROUND OF THE INVENTION 
     DE-PS No. 1,699,954 discloses bis-(2-ethylamino-4-diethylamino-s-triazine-6-yl) disulfide. This compound can be prepared, for example, from the corresponding monomercaptotriazine by oxidation with iodine or hydrogen peroxide. The compound obtained in this manner is used as a vulcanization accelerator in rubber mixtures. 
     The corresponding tetrasulfide is described in DE-OS No. 34 38 290. 
     The latter compound is produced by the reaction of a mercaptotriazine with S 2  Cl 2  and is used successfully in vulcanizable mixtures as a vulcanizing agent or as a vulcanization accelerator. 
     The same action is developed by such mixtures of bistriazinyl polysulfides in which the two triazine rings are not connected by a defined S 4  bridge but rather by a polysulfide chain with a statistical average length of four sulfur atoms (German patent application P No. 36 10 794). 
     SUMMARY OF THE INVENTION 
     The present invention is concerned with a method of producing mixtures of sulfurous triazine compounds of the general formula ##STR3## in which: R 1  and R 2  may be hydrogen, R 2  may be benzyl, R 2 , R 3  and R 4  may be C 1  -C 8  -alkyl, allyl, C 3  -C 8  cycloalkyl, the latter being unsubstituted or substituted with 1-3 methyl groups, 2-hydroxyethyl, 3-hydroxypropyl or 2-hydroxypropyl or R 3  and R 4  (together) may be C 4  -C 6  -alkylene, --(CH 2  --CHX) 2  Y where 
     X is hydrogen or CH 3  and Y is O or S, S a  is a polysulfide chain with 2-10 sulfur atoms (i.e. 2≦a≦10), in which the individual polysulfides are present in such proportions that the statistical average value of &#34;a&#34; is a whole or fractional numerical value in the range from 2 to 5. 
     The method of the invention comprises reacting a triazine compound of the general formula ##STR4## in which R 1 , R 2 , R 3 , R 4  have the meanings indicated above, with a compound of the formula 
     
         Me.sub.2 S.sub.a                                           III 
    
     dissolved in a protic polar solvent, especially water or its mixtures with water, in which Me signifies the ammonium cation or an alkali cation, preferably Na +   or K +   and  a  corresponds to the statistical average with 2≦a≦5 in a molar ratio of 2:1 to 2:1.1 at a temperature of 80° to 140° C. and the product is separated from the accumulating reaction mixture by known procedures. 
     The reaction is preferably allowed to occur at the reflux temperature which develops; water forms the main component of the solvent, especially at 95° to 100° C. However, it is also possible to perform the reaction at higher temperatures in a pressure vessel. 
     In a preferred embodiment, the molten compound of the Formula II is added dropwise into a strongly alkaline aqueous solution of Me 2  S a , which is heated to 100° C. 
     The pH decreases in the aqueous reaction mixture during the reaction. Therefore, in a preferred embodiment, an aqueous alkaline solution, e.g. sodium hydroxide solution or sodium bicarbonate solution, is continuously added during the reaction, especially if the solvent is predominantly or entirely water, so that the pH does not decrease below 9.0 to 7.5, especially to 8.5. 
     The Me 2  S a  added is statistically composed as concerns the length of the polysulfide chain. Therefore, the stoichiometric factor of 4 in Na 2  S 4 , for example, only implies that the S a   2  dianions with 2≦a≦10 present in the mixture are present in such proportions that the following relationship is fulfilled: ##EQU1## in which n=total number of dianions present 
     n a  =number of dianions of chain length a present 
       a  =statistical average. 
     Since all dianions present in Me 2  S a  exhibit nucleophilic properties in chemical reactions, it is possible to control the statistical composition of the polysulfide chain lengths by the selection of the raw material. 
     The reaction is completed after at most 3 hours at 100° C. in an aqueous medium. As a precaution, the reaction mixture can also be heated under a reflux for a longer time. 
     Subsequently, the sulfurous triazine derivative which forms a lower phase is allowed to run off as a hot liquid, and it is then cooled and residual moisture is removed by drying, e.g. in a vacuum. 
     The product may be converted into the finely divided particulate form necessary for use in rubber mixtures by conventional procedures, e.g. by grinding. 
     If analysis indicates free sulfur in the final product, a purification can be performed, e.g. by dissolving the crude product in hot ethanol. 
     Thereafter, impurities such as sulfur or NaCl can be separated out by filtration. 
     The process can be modified by introducing the Me 2  S a  in a solution in ethanol, for example, or by using n-propanol or glycol as a solvent alone, or in mixtures of those alcohols with water. 
     The triazine derivative according to Formula II is then added in powder form or, preferably, it is first dissolved or suspended in the corresponding alcohol or put up in another variant and then mixed with the Me 2  S a  solution. In order to separate the product, the reaction mixture can then be compounded with water, for example, and filtered. The insoluble filter residue is then dried and ground. 
     The invention also provides mixtures of sulfurous triazine compounds of the general formula ##STR5## in which: R 1  and R 2  may be hydrogen, R 2  may be benzyl, 
     R 2 , R 3  and R 4  may be C 1  - 8  - alkyl, allyl, C 3  -C 8  cycloalkyl, the latter being unsubstituted or substituted with 1-3 methyl groups, 2-hydroxyethyl, 3-hydroxypropyl or 2-hydroxypropyl or R 3  and R 4  (together) may be C 4  -C 6  -alkylene, --(CH 2  --CHX) 2  Y in which 
     X is H or CH 3  and Y is O or S, 
     S a  is a polysulfide chain with 2-10 sulfur atoms (i.e. 2≦a≦10), in which the individual polysulfides are present in such proportions that the statistical average value of &#34;a&#34; is a whole or fractional numerical value in the range from 2 to 5, with the exception of 4. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     When used as vulcanizing agents or vulcanization accelerators in rubber mixtures the compounds of the present invention produce vulcanizates having outstanding properties. 
     The following products are cited as examples of preferred mixtures which can be produced in accordance with the method of the invention: 
     A bis-(2-ethylamino-4-di-isopropylamino-s-triazin-6-yl)-oligosulfide 
     B bis-(2-n-butylamino-4-diethylamino-s-triazin-6-yl)-oligo-sulfide 
     C bis-(2-isopropylamino-4-di-isopropylamino-s-triazin-6-yl)-oligosulfide 
     D bis-(2-ethylamino-4-di-isobutylamino-s-triazin-6-yl)-oligosulfide 
     E bis-(2-ethylamino-4-di-n-propylamino-s-triazin-6-yl)-oligosulfide 
     F bis-(2-n-propylamino-4-diethylamino-s-triazin-6-yl)-oligosulfide 
     G bis-(2-n-propylamino-4-di-n-propylamino-s-triazin-6-yl)-oligosulfide 
     H bis-(2-n-butylamino-4-di-n-propylamino-s-triazin-6-yl)-oligosulfide 
     I bis-(2-ethylamino-4-di-n-butylamino-s-triazin-6-yl)-oligosulfide 
     K bis-(2-cyclohexylamino-4-diethylamino-s-triazin-6-yl)-oligosulfide 
     L bis-(2-ethylamino-4-diethylamino-s-triazin-6-yl)-oligosulfide 
     M bis-(2-amino-4-diethylamino-s-triazin-6-yl)-oligosulfide 
     The oligosulfides are mixtures of compounds in which the individual polysulfides have an S chain length in the range 2≦a≦10 and the proportions of the individual compounds are such that the statistical average of the S chain lengths is a whole or fractional numerical values in the range from 2 to 5 (2≦a -  ≦5). 
     The invention is illustrated by the following examples: 
    
    
     EXAMPLE 1 
     229.7 g (1.0 mole) 2-ethylamino-4-diethylamino-6-chlorotriazine, 95.8 g (0.55 mole) of a disodium polysulfide mixture having a statistical composition Na 2  S 4  (prepared in accordance with the procedure disclosed in DE-OS No. 34 36 698) as well as 1000 ml H 2  O are placed successively in a 2 liter three-neck flask which is equipped with a KPG agitator, reflux condenser and pH electrode, and this reaction mixture is heated to reflux temperature over a period of 30 minutes. The pH is initially 10.7, but it gradually drops and reaches a value of pH=8.5 after 2 hours reflux time. During this time, the color of the reaction medium changes from deep orange-brown to yellow. The mixture is agitated one hour further, under reflux, while the pH is held a ≧8.5 by adding an aqueous NaOH solution (20%) (consumption: 0.1 mole NaOH). After the KPG agitator is turned off, a 2-phase system develops, in which the heavier portion consists essentially of the product mixture. This layer is separated via a bottom outlet valve from the aqueous phase and solidifies to a yellowish brown amber-like solid (solidification point approx. 90° C.). The approximately 5% of moisture residues contained therein are removed by vacuum treatment (15 torr) at 95° C. for 16 hours until a residual moisture of ≦0.5%. The solid obtained in this manner can be comminuted in a mortar to a powder which can trickle at room temperature. This powder can dissolve in ethanol to form a clear solution, that is, it contains no significant amounts of elementary sulfur or of NaCl. 
     Yield: 246.5 g corresponding to 95.4% of theory, bright yellow powder. 
     Elementary analysis: C 18  H 32  N 10  S 4  (516.76) 
     
         ______________________________________                                    
        C       H      N         S    Cl                                  
______________________________________                                    
calculated:                                                               
          41.84     6.24   27.10   24.82                                  
                                        0                                 
found:    41.07     6.24   26.80   24.80                                  
                                        0.1                               
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     HPLC analysis (according to a known method, K. O. Hiller et al.; Zeitschrift Analyt. Chem. Vol 280 (1976) p. 293: 
     
         ______________________________________                                    
Compound (*)   rel. area % (**)                                           
______________________________________                                    
R--S.sub.2 --R 48.5                                                       
R--S.sub.3 --R 12.6                                                       
R--S.sub.4 --R 18.8                                                       
R--S.sub.5 --R 8.8                                                        
R--S.sub.6 --R 6.7                                                        
R--S.sub.7 --R 3.1                                                        
R--S.sub.8 --R 1.5                                                        
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 (*) R = 2ethylamino-4-diethylamino-6-triazinyl                           
 (**) neglecting the peak areas caused by the mobile solvent,             
 standardization at 100 area %                                            
 
    
     EXAMPLE 2 
     25.5 g (0.130) mole diammonium pentasulfide (preparation according to J. S. Thomas et al., J. Chem. Soc. 1923, pp. 1726 ff.) are dissolved in 300 ml water in a standard apparatus analogous to the one described in Example 1. 57.4 g (0.25 mole) liquified 2-ethylamino-4-diethylamino-6-chlorotriazine (melting point: 98° C.) was added to the reddish brown ammonium polysulfide solution at reflux temperature within 30 min. from a heated dropping funnel while the mixture was agitated. The reaction solution is agitated for another 90 min. under reflux, while the initially measured pH of 11.7 drops slowly to 8.0. The pH is maintained for the following 60 min. at 9.0 by adding an aqueous NaOH solution (consumption: 0.04 mole NaOH). As was described in Example 1, the preparation mixture is isolated through a bottom outlet valve, dried and powdered. 66.3 g of a yellowish powder is obtained which is not completely soluble in hot ethanol. After treatment in a Soxhlet extractor with 150 ml ethanol, 2.6 g of a yellow powder with a sulfur content of 98.6% remains. The preparation is isolated from the extract by means of drawing off the solvent. 
     Yield: 63.2 g corresponding to 92.1% of theory (in relation to a statistically composed pentasulfane), bright yellow powder 
     Elementary analysis: C 18  H 32  N 10  S 4 .5 (532.79) 
     
         ______________________________________                                    
        C       H      N         S    Cl                                  
______________________________________                                    
calculated:                                                               
          40.58     6.05   26.29   27.08                                  
                                        0                                 
found:    41.12     6.43   27.12   26.61                                  
                                        0.2                               
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     HPLC-analysis 
     
         ______________________________________                                    
Association   Rel. area %                                                 
______________________________________                                    
R--S.sub.2 --R                                                            
              9.0                                                         
R--S.sub.3 --R                                                            
              29.8                                                        
R--S.sub.4 --R                                                            
              37.8                                                        
R--S.sub.5 --R                                                            
              12.4                                                        
R--S.sub.6 --R                                                            
              6.5                                                         
R--S.sub.7 --R                                                            
              3.1                                                         
R--S.sub.8 --R                                                            
              1.4                                                         
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     EXAMPLE 3 
     The method described in example 1 is performed with the following starting materials: 
     71.4 g (0.25 mole) 2-ethylamino-4-di-n-butylamino-6-chlorotriazine; 
     22.7 g dipotassium trisulfide (preparation cf. Brauer, vol. 1, p. 375); 
     250 ml water. 
     71.8 g of a bright yellow solid corresponding to 96.3% of m. are isolated which gave the following analytical data: 
     C 26  H 48  N 10  S 3  (596.93): 
     
         ______________________________________                                    
        C       H      N         S    Cl                                  
______________________________________                                    
calculated:                                                               
          52.31     8.11   23.46   16.11                                  
                                        0                                 
found:    52.67     8.62   23.83   15.89                                  
                                        0.15                              
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     The HPLC diagram contains signals for bistriazinyl disulfane (45.7% area), the corresponding tri- (39.1%), tetra- (12.8%) and pentasulfane (2.4%). 
     EXAMPLE 4 
     The method described in Example 1 is performed with the following materials: 
     71 g (0.25 mole) 2-cyclohexylamino-4-diethylamino-6-chlorotriazine; 
     13.8 g (0.13 mole) disodium disulfide (preparation cf. Brauer, vol. 1, p. 374); 
     300 ml water. 
     54.3 g of bright yellow solid corresponding to 87.4% of m. are isolated with the following analytical data: 
     C 26  H 44  N 10  S 2  (560.84): 
     
         ______________________________________                                    
        C       H      N         S    Cl                                  
______________________________________                                    
calculated:                                                               
          55.68     7.91   24.97   11.43                                  
                                        0                                 
found:    56.21     7.98   25.31   10.73                                  
                                        0.4                               
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     The HPLC diagram contains signals for bistriazinyl disulfane (89.1 area %) adjacent to signals for the corresponding tri-(9.7%) and tetrasulfane (1.2%). 
     EXAMPLES 5-9 
     The method described in Example 2 (addition of 2-ethylamino-4-diethylamino-6-chlorotriazine in liquid form) was performed using disodium polysulfides (preparation from the elements according to DE-OS No. 34 36 698) in various solvents. Reaction and preparation data are listed in Tables 1 and 2. For product preparation, the reaction mixture was compounded with water at 95° C. until a distinct phase separation of the molten bistriazinyl polysulfides from the solvents had occurred. 
     
                                           TABLE 1                                 
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Reaction Data for Examples 5-9                                            
                Proportions       Reaction Conditions                     
Example     a in                                                          
                Chlorotriazine (*)                                        
                         Na.sub.2 S.sub.a                                 
                             Solvent                                      
                                  Time                                    
                                      Temperature                         
No.  Solvent                                                              
            Na.sub.2 S.sub.a                                              
                (mol)    (mol)                                            
                             (ml) (hours)                                 
                                      (°C.)                        
__________________________________________________________________________
5    Ethanol                                                              
            4.0 0.5      0.25                                             
                             200  5.0 120 (**)                            
6    Glycol 4.5 0.25     0.13                                             
                             150  6.5 100-140                             
7    n-propanol +                                                         
            4.0 0.25     0.13                                             
                             150 +                                        
                                  5.5 93-98                               
     water                   25                                           
8    glycol 3.5 0.25     0.13                                             
                             150  6.0 100-140                             
9    glycol 5.0 0.25     0.13                                             
                             200  4.5 100-140                             
__________________________________________________________________________
 (*) denotes 2ethylamino-4-diethylamino-6-chlorotriazine                  
 (**) autoclave test                                                      
 
    
     
                       TABLE 2                                                     
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Product Data for Examples 5- 9                                            
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Example                                                                   
       Raw Yield Amount   Elemental Analysis (**) (%)                     
No.    %         of S.sub.8 (*)                                           
                          C    H    N    S    Cl                          
______________________________________                                    
5      72.5      6.2      44.93                                           
                               7.00 29.07                                 
                                         19.70                            
                                              0.1                         
6      83.4      --       39.74                                           
                               6.00 25.04                                 
                                         26.00                            
                                              0.3                         
7      90.5      --       41.68                                           
                               6.18 28.29                                 
                                         24.10                            
                                              0.2                         
8      79.3      --       44.21                                           
                               6.41 27.82                                 
                                         23.10                            
                                              0.2                         
9      74.7      3.8      40.91                                           
                               6.21 27.07                                 
                                         26.70                            
                                              0.3                         
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(*) determined by extraction with ethanol                                 
(**) Calculated for                                                       
       C      H      N    S                                               
a = 3.0                                                                   
       44.60  6.65   28.90                                                
                          19.84                                           
a = 3.5                                                                   
       43.18  6.64   27.97                                                
                          22.41                                           
a = 4.0                                                                   
       41.84  6.24   27.10                                                
                          24.82                                           
a = 4.5                                                                   
       40.58  6.05   26.29                                                
                          27.08                                           
a = 5.0                                                                   
       39.39  5.88   25.82                                                
                          29.21