Process for the production of monoperoxydicarboxylic acids and their salts
BACKGROUND OF THE INVENTION 
     The invention is directed to the production of monoperoxydicarboxylic acids and their salts. 
     It has long been known to use these compounds as bleaching agents in washing compositions. 
     There is described in Australian Patent No. 417,480 the improved bleaching action of monoperoxyphthalic acid in the present Mg 2+   ions in the bleach liquor. The French Patent No. 2,129,034 is directed to the production of stable monoperoxyphthalic acid from phthalic anhydride and hydrogen peroxide in the presence of 0.01 to 1 mole of magnesium oxide per mole of anhydride. The magnesium salt of the peracid is formed at least in part therefrom and the peracid is precipitated by the addition of a strong mineral acid. 
     An alkaline acting magnesium compound likewise is necessary according to European patent No. B1-0027693 in order to carry out the oxidation of phthalic anhydride with hydrogen peroxide and simultaneously obtain the magnesium salt of the monoperoxyphthalic acid. 
     The production of monomperoxyphthalic acid is described in the Acta Chem. Scand. Vol. 12 (1958) 6, page 1331. In order to attain sufficient yield, it is necessary to react the phthalic anhydride at a temperature of below -5° C. with the alkaline oxidation solution. The peracid is separated off after treatment of the solution with sulfuric acid and water by extraction with ether. 
     The object of the invention is to develop a process of obtaining monoperoxydicarboxylic acids and their salts in a simple manner. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a process for the production of monoperoxydicarboxylic acids (hereinafter called percarboxylic acids) and their salts by oxidation of the corresponding anhydrides with hydrogen peroxide in an organic solvent which dissolves the peracid formed comprising carrying out the oxidation in the presence of an anion exchanger, after completing the reaction separating off the anion exchanger and isolating the monoperoxydicarboxylic acid from the solution or precipitating the corresponding salt by addition of an alkaline active alkali or alkaline earth metal salt. 
     As anhydrides, there are employed compounds of the following formulae; ##STR1## wherein R 1  and R 2  are the same or different and are hydrogen, linear or branched C 1  -C 18  alkyl, n is 0 or 1 to 10, especially 0 to 2 or 3, preferred are the anhydrides of glutaric acid, succinic acid, and their single alkylated derivatives whose alkyl group contains 1 to 18 carbon atoms, ##STR2## where R 1  and R 2  are as defined above, preferred are the anhydrides of maleic acid and citraconic acid; ##STR3## where R 3 , R 4 , R 5 , and R 6  are the same or different and are hydrogen, linear, or branched C 1  -C 10  alkyl, the sulfonate or nitro group, chlorine or bromine or R 3  and R 4  or R 4  and R 5  or R 5  and R 6  are eliminated and between the corresponding ring carbon atoms there is a double bond, preferred are the anhydrides of cyclohexane (1,2)-dicarboxylic acid, 4-methylcyclohexane-1,2-dicarboxylic acid, 4-ethyl cyclohexane-1,2-dicarboxylic acid; or ##STR4## where R 7 , R 8 , R 9 , and R 10  are the same or different and are hydrogen, linear, or branched C 1  -C 10  alkyl, the sulfonate or nitro group, chlorine or bromine, preferably there is employed the anhydride of o-phthalic acid. 
     Illustrative of suitable acids whose anhydrides can be used in addition to those mentioned above or in the working examples are oxalic acid, malonic acid, adipic acid, sebacic acid, dodecanedioic acid, dimethyl succinic acid, dibutylsuccinic acid, isopropylsuccinic acid, octadecyl succinic acid, butylmaleic acid, octadecylmaleic acid, 4-decyclohexane (1,2)-dicarboxylic acid, 4,5-dimethyl-cyclohexane (1,2)-dicarboxylic acid, 4-isopropyl-cyclohexane (1,2)-dicarboxylic acid, 4-nitro-cyclohexane (1,2)-dicarboxylic acid, 4-sulfonic acid cyclohexane (1,2)-dicarboxylic acid, 3,4-dichloro-cyclohexane (1,2)-dicarboxylic acid, 3-chlorocyclohexane (1,2)-dicarboxylic acid, 4-bromocyclohexane (1,2)-dicarboxylic acid, 4-cyclohexene-(1,2)-dicarboxylic acid, 3-methylphthalic acid, 4-decylphthalic acid, 3,4-diethylphthalic acid, 4-nitrophthalic acid, benzene-1,2-dicarboxylic acid-4-sulfonic acid, 3-chlorophthalic acid, 4-tromophthalic acid, 3,4-dichlorophthalic acid. 
     Hydrogen peroxide can be used on the form of aqueous solutions whose peroxide concentration is 20-99%, preferably 40 to 60 weight %. 
     Especially suited is the illustrative form in which the water content of the oxidation mixture does not lead to the formation of an emulsion with the solvent. 
     Hydrogen peroxide is employed in the stoichiometric ratio 1:1 to the anhydride. However, a slight excess of up to 0.2 mole, preferably 0.1 mole of hydrogen peroxide is advantageous. 
     The range of the amount of basic ion exchanger to anhydride is from 0.1 gram to 50 grams, preferably 10 to 20 grams of ion exchanger per mole of anhydride. 
     The particluar basic ion exchanger is not critical. Preferred are weakly basic anion exchangers with the proviso that they are stable to oxidation. 
     These specifications can be obtained without difficulty from the brochures of the commerically available ion-exchangers e.g., ion exchange resins. 
     Illustrative anion exchangers are shown, for example, in the Encyclopedia of Polymer Science and Technology Vol. 7, pages 695 and 697-699 (Interscience Publishers, 1967). Specifically there is recited: 
     
                       TABLE 1                                                     
______________________________________                                    
Manufacturers of Ion Exchange Resins in the United States in 1966         
Company      Location         Trade name                                  
______________________________________                                    
Diamond Alkali Co.                                                        
             Redwood City, California                                     
                              Duolite                                     
Dow Chemical Co.                                                          
             Midland, Michigan                                            
                              Dowex*                                      
Jonac Chemical Co.                                                        
             Birmingham, New Jersey                                       
                              Ionac                                       
Rohm and Haas Co.                                                         
             Philadelphia, Pennsylvania                                   
                              Amberlite                                   
______________________________________                                    
 *The Dowex resins are marketed by the Nalco Chemical Company.            
 
    
     
                       TABLE 2                                                     
______________________________________                                    
Commercial Resins Manufactured Outside the United States                  
Trade name                                                                
         Manufacturer                                                     
______________________________________                                    
Allassion                                                                 
         Dia-Prosim, Vitry-sur-Seine, France                              
Anionite Soviet Union                                                     
De-Acidite                                                                
         The Permutit Co. Ltd., London                                    
Diaion   Mitsubishi Chemical Industries, Ltd., Tokyo                      
Imac     Industrieele Maatschappij Activit, Amsterdam                     
Kastel   Montecatini, Milan                                               
Kationite                                                                 
         Soviet Union                                                     
Lewatit  Farbenfabriken Bayer Aktiengesellschaft,                         
         Leverkusen, West Germany                                         
Wofatit  VEB Farbenfabrik Wolfen, Wolfen Kr. Bitterfeld                   
         East Germany                                                     
Zeo-Karb The Permutit Co., Ltd., London                                   
______________________________________                                    
 
    
     Classification 
     More than one hundred synthetic ion-exchange resings are marketed throughout the world. These may be broadly classified as cation- and anion-exchange materials which contain fixed anionic and cationic groups, respectively. The cation-exchange resins are subclassified into strong-acid and weak-acid types; similarly, the anion-exchange resins are divided into strong-base and weak-base materials. The active groups associated with each of these classifications are listed in Table 4. 
     
                                           TABLE 3                                 
__________________________________________________________________________
Tradenames of Commercial Ion-exchange Resins                              
__________________________________________________________________________
Strong-base anion-exchange resins.sup.b                                   
                                     Particle                             
                                          Total capacity                  
Trade name                                                                
          Matrix Structure                                                
                        Active group shape                                
                                          eq/l                            
                                              meq/g                       
__________________________________________________________________________
Allassion AQ217                                                           
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.3 3.2                         
Amberlite IRA-400                                                         
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.4 3.3                         
Amberlite IRA-900                                                         
          polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.0 3.0                         
Amberlite IRA-904                                                         
          polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          0.7                             
Anionite AV-17                                                            
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
De-Acidite FF(IP)                                                         
          polystyrene                                                     
                 &#34;isoporous&#34;                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.2 4.0                         
Diaion SA-10A                                                             
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.4 3.4                         
Dowex 1   polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.4 3.5                         
Dowex 21K polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.3 4.2                         
Duolite A-101D                                                            
          polystyrene                                                     
                 semiporous                                               
                        --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.4 4.2                         
Duolite A-111                                                             
          polystyrene                                                     
                 semiporous                                               
                        --N.sup. ⊕ (CH.sub.2).sub.2 Cl.sup.⊖  
                                     spherical                            
                                          1.0 4.2                         
ImacS5-40 polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.1 3.4                         
ImacS5-5- polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.3 3.6                         
Kastel A-500                                                              
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.2 3.3                         
Ionac A-540                                                               
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.3 3.6                         
Lewatit M-500                                                             
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.4 3.6                         
Lewatit MP-500                                                            
          polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.1 3.6                         
Wofatit SBW                                                               
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 Cl.sup.⊖   
                                     spherical                            
                                          1.3 3.5                         
Allassin AQ227                                                            
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.4 3.4                         
Amberlite IRA-410                                                         
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.4 3.5                         
Amberlite IRA-910                                                         
          polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.1                             
Diaion SA-20A                                                             
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.4 3.5                         
Dowex 2   polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.4 3.5                         
Duolite A-102D                                                            
          polystyrene                                                     
                 semiporous                                               
                        --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.4 3.6                         
Imac S 5-52                                                               
          polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.3 3.4                         
Ionac A-550                                                               
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.3 3.4                         
Kastel A-300                                                              
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.2 3.1                         
Lewatit M-600                                                             
          polystyrene                                                     
                 gel    --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup.⊖                               
                                     spherical                            
                                          1.4 3.6                         
Lewatit MP-600                                                            
          polystyrene                                                     
                 macroporous                                              
                        --N.sup.⊕ (CH.sub.2).sub.2 (C.sub.2 H.sub.4   
                        OH)Cl.sup. ⊖                              
                                     spherical                            
                                          1.1 3.3                         
Weak-base anion-exchange resins.sup.c                                     
Allassion A33-03                                                          
          polystyrene                                                     
                 &#34;equiporous&#34;                                             
                        --NR:        spherical                            
                                          1.2                             
Amberlite IRA-45                                                          
          polystyrene                                                     
                 &#34;equiporous&#34;                                             
                        --NR.sub.2,--NHR,--NH:                            
                                     spherical                            
                                          2.3 5.6                         
Amberlite IRA-93                                                          
          polystyrene                                                     
                 macroporous                                              
                        --NR.sub.2   spherical                            
                                          1.4                             
De-Acidite G                                                              
          polystyrene                                                     
                 gel    --N(C.sub.2 H.sub.2).sub.2                        
                                     spherical                            
                                          1.6 4.0                         
De-Acidite M                                                              
          polystyrene                                                     
                 gel    --NR.sub.2,--NHR,--NH.sub.2                       
                                     spherical                            
                                          2.2 5.8                         
Dowex 3   polystyrene                                                     
                 gel    --NR.sub.2,--NHR,--NH.sub.2                       
                                     spherical                            
                                          2.6 5.8                         
Imac A-20 polystyrene                                                     
                 macroporous                                              
                        --NR.sub.2,--NHR,--NH.sub.2                       
                                     spherical                            
                                          2.3                             
Imac A-21 polystyrene                                                     
                 macroporous                                              
                        --NR.sub.2   spherical                            
                                          1.6                             
Ionac A-315                                                               
          polystyrene                                                     
                 macroporous                                              
                        --NR.sub.2,--NHR,--NH.sub.2                       
                                     spherical                            
                                          2.3 5.6                         
Lewatit MP-60                                                             
          polystyrene                                                     
                 macroporous                                              
                        --NHR,--NR.sub.2                                  
                                     spherical                            
                                          2.2 5.8                         
Allassion AWB-3                                                           
          epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     spherical                            
                                          1.9 8.2                         
Anionite EDE-10P                                                          
          epoxy-amine                                                     
                 gel    --NR.sub.2,--NHR,--N.sup.⊕ R.sub.3            
                                     spherical                            
Anionite AV-16                                                            
          epoxy-amine                                                     
                 gel    --NHR,--NR.sub.2,--NC.sub.6 H.sub.5 R             
                                     spherical                            
Dowex 44  epoxy-amine                                                     
                 gel    --NHR,--NR.sub.2                                  
                                     clusters                             
                                          2.4 8.5                         
Duolite A-30B                                                             
          epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     spherical                            
                                          2.5 8.6                         
Duolite A-57                                                              
          epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     spherical                            
                                          2.2 8.7                         
Imac      epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     spherical                            
                                          2.5 8.5                         
Ionac A-300                                                               
          epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     granular                             
                                          2.5 8.6                         
Ionac A-310                                                               
          epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     spherical                            
                                          2.1 8.0                         
Wofatit L-50                                                              
          epoxy-amine                                                     
                 gel    --NR.sub.2,--N.sup.⊕ R.sub.3                  
                                     granular                             
                                          2.5 8.8                         
Anionite AN-2F                                                            
          phenolic                                                        
                 gel    --NHR,--NR.sub.2                                  
                                     granular                             
De-Acidite E                                                              
          phenolic                                                        
                 gel    --NHR,--NR.sub.2,--NH.sub.2                       
                                     granular                             
                                          1.0 4.5                         
Duolite A-6                                                               
          phenolic                                                        
                 macroporous                                              
                        --NR.sub.2   granular                             
                                          2.4 7.3                         
Duolite A-7                                                               
          phenolic                                                        
                 macroporous                                              
                        --NHR,--NH.sub.2                                  
                                     granular                             
                                          2.5 9.1                         
Lewatit MIH 59                                                            
          condensate                                                      
                 gel    --NHR,--NH.sub.2                                  
                                     granular                             
                                          2.2 6.0                         
Wofatit MD                                                                
          condensate                                                      
                 gel    --C.sub.6 H.sub.4 NH.sub.2,--NHR                  
                                     granular                             
                                          2.0 5.7                         
__________________________________________________________________________
 .sup.b The total capacity applies to the Cl form.                        
 .sup.c The total capacity applies to the freebase form.                  
 
    
     Quaternary ammonium derivatives of this copolymer are in common use as strong-base anion-exchange resins, whereas secondary and tertiary amine derivatives serve as weak-base anion-exchange resins. Phenol-formaldehyde condensates are still used in making strong-acid cation-exchange resins and some rather specialized, but important, weak-base anion-exchange resins. Phenolic resins are sometimes employed for making weak-acid cation-exchange materials, but these are not as widely used as those based on copolymers of acrylic or methacrylic acids or esters or the corresponding nitriles. A third class of polymer, used in making weak-base anion-exchange resins results from the condensation of epichlorohydrin with amines. 
     
                       TABLE 4                                                     
______________________________________                                    
Chemical Classification of Ion-Exchange Resins                            
Classification                                                            
          Active group Typical configuration                              
______________________________________                                    
Anion-exchange resins                                                     
strong base                                                               
          quaternary ammonium                                             
                        ##STR5##                                          
weak base secondary amine                                                 
                        ##STR6##                                          
weak base tertiary amine (aromatic matrix)                                
                        ##STR7##                                          
weak base tertiary amine (aliphatic matrix)                               
                        ##STR8##                                          
______________________________________                                    
 
    
     The use of the ion exchanger in contrast to the process according to the state of the art makes possible the continuous production of the peracids of the invention, by, e.g., bringing the reaction mixture into contact with the ion exchanger over a sufficiently long stretch. 
     With the process of the invention, there is formed directly the monoperoxycarboxylic acid without the presence of the customary basic salts such as, e.g., alkali or alkaline earth hydroxides or basic carbonates and without addition of mineral acids. 
     The production of these peroxyacids was previously made difficult by the fact that most suitable point in time for acidifying the reaction mixture could not be predicted exactly. 
     If a salt of the peracid is desired, there is added after the separation of the ion exchanger to the remainder of the reaction solution an alkali or alkaline earth oxide, preferably a magnesium compound, in an amount theoretically sufficient to neutralize the remaining carboxy group and preferably in an excess of 1%. The especially suited magnesium hydroxide is used in a mole ratio of at least 1:2 based on the peracid. 
     Especially suited are magnesium hydroxide/peracid mole ratios of 1:2 to 1.1:2. Other alkali or alkaline earth compounds include, for example, magnesium oxide, magnesium carbonate, calcium hydroxide, calcium oxide, barium hydroxide, sodium hydroxide, sodium oxide, sodium carbonate, potassium hydroxide, potassium oxide, and potassium carbonate. 
     In the case of the monoperoxyphthalic acid, there is formed the hydrated salt. ##STR9## The sequence of addition of anhydride to the organic solvent is not decisive. 
     However, it is important that the temperature in the reaction of anhydride and hydrogen peroxide be controlled. The rection temperature is in the range of -10° C. to +50° C., preferably 0° C. to 20° C., especially 10° to 20° C. 
     Reaction times of 5 minutes to 5 hours, preferably 10 minutes to 1 hour, are employed. 
     The reaction between the alkaline, alkali, or alkaline earth metal compound and the monoperoxydicarboxylic acid formed is preferably carried out between 15° C. and 20° C. with a reaction time of 2 to 20 minutes. 
     The salt of the peracid formed is separated off subsequently according to the rules of the art, e.g., via a filter of centrifuge. It is preferred to wash subsequently with a non-aqueous solvent in order to dissolve out any residual anhydride which might be present. 
     As organic solvent, there is employed a low molecular weight aliphatic ester, preferably an acetate and especially ethyl acetate. Other solvents include alkyl alkanoates such as methyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, and methyl butyrate. 
     The anhydride employed must at least be dissolved, the alkali or alkaline earth metals salts of the peracid do not dissolve in the solvent employed. 
     The process can comprise, consist essentially of, or consist of the recited steps with the stated material. 
    
    
     DETAILED DESCRIPTION 
     EXAMPLE 1 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, there were dropped in at the same temperature with stirring 11.5 grams of 50 wt. % hydrogen peroxide. Stirring was containued for 1 hour, whereby the temperature of the mixture increased to about 20° C. Then there was separated off the ion exchanger and there were obtained from the solution 25.4 grams of monoperoxyphthalic acid having an AO content of 7.0%. 
     EXAMPLE 2 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, there were dropped in with stirring 11. 5 grams of 50 wt. % hydrogen peroxide at the same temperature. Then the mixture was stirred for 1 more hour whereby the temperature of the mixture increased to about 20° C. Then there was separated off the ion exchanger and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 31 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO Content of 5.1%. 
     EXAMPLE 3 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, there were dropped in at the same temperature with stirring 11.5 grams of 50 wt. % hydrogen peroxide. Then the mixture was stirred for a further 3 hours whereby the temperature of the mixture increased to about 20° C. Then the ion exchanger was separated off and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 27 grams of hydrated monoperoxyphthalic acid mono Mg salt with an AO content of 5.4%. 
     EXAMPLE 4 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and tempered at 20° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, there were dropped in with stirring at the same temperature 11.5 grams of 50 wt. % hydrogen peroxide. Then the mixture was further stirred for 1  hour at this temperature. Then the ion exchanger was separated off and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 23 gram of hydrated monoperoxyphthalic acid mono-Mg salt having an AO content of 5.2%. 
     EXAMPLE 5 
     25 grams of phthalic anhydride were dissolved in 100 ml of ethyl acetate and tempered at 20° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, there were dropped in at the same temperature with stirring 11.5 grams of 50 wt. % hydrogen peroxide. The mixture was stirred for 1 more hour at 30° C. Then the ion exchanger was separated off and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 25 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO content of 5.2%. 
     EXAMPLE 6 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there was added 1 gram of Lewatit MP 62. Subsequently, within 15 minutes, at the same temperature with stirring there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide, Stirring was continued for 1 more hour, whereby the temperature of the mixture increased to about 20° C. Then the ion exchanger was separated off and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 25 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO content of 5.4%. 
     EXAMPLE 7 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, at the same temperature with stirring there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continued for 1 hour, whereby the temperature of the mixture increased to about 20° C. Then the ion exchanger was separated off and after neutralization with 3.4 grams of magnesium oxide at 20° C. in 15 minutes and drying there were obtained 23 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO content of 5.2%. 
     EXAMPLE 8 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, at the same temperature and with stirring there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continued for 1 hour whereby the temperature of the mixture increased to about 20° C. Then the ion exchanger was separated off and after neutralization with 9.8 grams of basic magnesium carbonate at 20° C. in 15 minutes and drying there were obtained 12 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO content of 2.3%. 
     EXAMPLE 9 
     25 grams of phthalic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, at the same temperature and with stirring there were dropped in 20 grams of 30 wt. % hydrogen peroxide. Then stirring was continued for 1 hour, whereby the temperature of the mixture increased to about 20° C. Then the ion exchanger was separated off and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 18 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO content of 4.9%. 
     EXAMPLE 10 
     25 grams of phthalic anhydride were dissolved in 100 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 15 minutes, at the same temperature and with stirring there were dropped in 15 grams of 40 wt. % hydrogen peroxide. Then stirring was continued for 1 hour, whereby the temperature of the mixture increased to about 20° C. Then there was separated off the ion exchanger and after neutralization with 5 grams of magnesium hydroxide at 20° C. in 15 minutes and drying there were obtained 25 grams of hydrated monoperoxyphthalic acid mono Mg salt having an AO content of 5.3%. 
     EXAMPLE 11 
     16.7 grams of maleic anhydride were dissolved in 150 ml of ethyl acetate and cooled to 0° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 10 minutes, at the same temperature and with stirring there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continued for 1 hour, whereby the temperature was held between 0° and 5° C. Then there was separated off the ion exchanger and there were obtained from the solution 16 grams of monoperoxymaleic acid having an AO content of 10.8%. 
     EXAMPLE 12 
     19.4 grams of glutaric anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 5 minutes, at the same temperature and with stirring, there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continues for 1 hour whereby the temperature of the mixture increased to about 20° C. Then there was separated off the ion exchanger and there were obtained from the solution 21 grams of monoperoxyglutaric acid having an AO content of 5.7%. 
     EXAMPLE 13 
     26.2 grams of cyclohexane-1,2-dicarboxylic acid anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 5 minutes at the same temperature and with stirring, there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continued to 1 hour, whereby the temperature increased to about 20° C. Then there was separated off the ion exchanger and there were obtained from the solution 25 grams of monoperoxycyclohexane-1,2-dicarboxylic acid having an AO content of 4.0%. 
     EXAMPLE 14 
     28.6 grams of 4-methylcyclohexane, 1,2-dicarboxylic acid anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 5 minutes, at the same temperature and with stirring there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continued for 1 hour whereby the temperature increased to about 20° C. Then there was separated off the ion exchanger and there were obtained from the solution 28 grams of monoperoxy-4-methylcyclohexane-1,2-dicarboxylic acid having an AO content of 4.0%. 
     EXAMPLE 15 
     36.1 grams of octylsuccinic acid anhydride were dissolved in 150 ml of ethyl acetate and cooled to 10° C. Then there were added 3 grams of Lewatit MP 62. Subsequently, within 5 minutes, at the same temperature and with stirring, there were dropped in 11.5 grams of 50 wt. % hydrogen peroxide. Then stirring was continued for 1 hour, whereby the temperature increased to about 20° C. Then the ion exchanger was separated off and there were obtained from the solution 37 grams of monoperoxy-2-octylsuccinic acid having an AO content of 3.5%. 
     EXAMPLE 16 
     14.8 grams of tetradecylsuccinic acid anhydride were dissolved in 100 ml of ethyl acetate and cooled to 10° C. Then there was added 1 gram of Lewatit MP 62. Subsequently, within 10 minutes, at the same temperature and with stirring, there were dropped in 3.4 grams of 50 wt. % hydrogen peroxide. Then stirring was continued for 3 hours, whereby the temperature increased to about 20° C. Then the ion exchanger was separated off and there were obtained from the solution 9 grams of monoperoxy-2-tetradecylsuccinic acid having an AO content of 2.7. 
     The entire disclosure of German priority application No. P.3426792.1 is hereby incorporated by reference.