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        ChemicalBook
        CAS DataBase List
        Glyoxylic acid
        
    
    
    
    
        
    
            
    
                298-12-4
            
    
        
    
        
    
            Glyoxylic acid synthesis
        
    
        
    14synthesis methods
    
        
    
    

    
    
    
        
    
            Add to 3500ml reactor equipped with reflux condenser, stirrer and thermometer300ml (3.55mol) of 50% glyoxal solution, stir and cool, control the temperature to 7±2,Slowly drip 300ml (3.55mol) of 35% hydrogen peroxide solution at the same time within 3 hours,280ml (0.355mol) of 17% ferrous sulfate solution and 120ml (0.75mol) of 15% aqueous ammonia solution, keep at 8±2, react for 3 hours, and let stand overnight, The reaction liquid was filtered to remove the solid by-products, and 350ml of water-carrying toluene was added to the reaction mother liquid.Heat to reflux, remove water, and distill toluene with water-carrying agent to obtain oxidation product.Add 120ml of concentrated sulfuric acid and 700ml of absolute ethanol to the oxidation products.Esterification reaction at 140°C for 3 hours, then distillation under reduced pressure, at 0.02Mpa,The esterification product was collected at 185°C.Add 120ml of 18% sulfuric acid to the esterified product and heat under stirring.The hydrolysis reaction is carried out at 95-98 for 2 hours; the hydrolysis liquid is cooled to room temperature,The precipitated white solid product was filtered, washed 4 times with 120ml of toluene each time, and dried.Obtain 180 g of the target product glyoxylic acid with a purity of 99.5% (HPLC) and a yield of 88%.Melting point is 98.1-98.6.

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    Yield:298-12-4 98.3% 
    
                
                
    Reaction Conditions:
    
                
    Stage #1: maleic anhydridewith water in methanol;ethyl acetate at 65; for 0.833333 h;
    Stage #2: with ozone in methanol;ethyl acetate at 5; for 3 h;Solvent;Temperature;Time;
    
                
                
    Steps:
    
                
    
                    1 Example 1

    a. Melt 19.6120g of maleic anhydride in hydrolysis reactor. Heat in water bath. Add 5mL steam distilled water+5mL methanol+10mL ethyl acetate and undergo hydrolysis. Hydrolysis temp 65C, hydrolysis time 50min. b. After hydrolysis, transfer hydrolysate in self-made bubbling reactor. Supply with 5mL methanol+10mL ethyl acetate mixed solvent. Undergo ozonolysis. Ozone was bubbled from the bottom of the maleic acid solution so that ozone and the solution can completely come in contact. Control reaction temperature 5C, time 3h. c. At the end of the ozone oxidation phase, the passage of ozone was stopped and the residual ozone of the system was purged for 10 min. d. The reaction solution was slowly added to 8% sulfuric acid solution, and the control system temperature was 55 to 65 °C. e. After all addition, about a certain amount of CaO was added slowly, followed by the addition of 5 mL of water and the temperature was below controlled to below 10 ° C. Thereafter, the solution was allowed to stand to precipitate and the CaSO4 precipitate was removed by filtration to give a pale yellow solution. f. The resulting solution was transferred to a three-necked flask and several zeolites were added. In a 55C water bath, undergo vacuum distillation. Control pressure at 4.7kPa. Always observe the temperature of the solution, the control temperature should not exceed 55 .When the temperature of the solution is constant, stop heating. The distilled out formic acid and the mixed solvent are returned to step a for reuse. g. At the end of the vacuum distillation, the remaining solution was crystallized and cooled at 5 ° C for 3 days. h. glyoxylic acid product undergoes testing. Melting point of the product is 52.5C, yield is 98.3%. By liquid chromatography analysis of production, the purity of the product is 98%.
                
    
                
                
    References:
    
                
    
                    CN106431885,2017,A Location in patent:Paragraph 0068; 0069; 0070; 0071; 0072; 0073; 0074-0121
                
    
                
            
    
            
        
    
        
        
        
        
        
        
        
        
        
    
    

    
    
    
        
        
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