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(I) adding antipyrine to the preparation tank, adding the amount of sulfuric acid and water, formulating an acidic solution with a content of 34-36%, and then performing nitrosation reaction with the sodium nitrite solution in a nitrosated keg, The reaction liquid is placed in a reduction tank, a reducing agent is added to carry out a reduction reaction, and the reducing liquid is transferred to a hydrolysis tank, and after hydrolysis with sulfuric acid is added, ammonia gas is neutralized to obtain 4-aminoantipyrine oil;
(2) adding 4-aminoantipyrine oil to an acylation tank for acylation with methyl formate or formic acid, followed by cooling and crystallizing to obtain 4-formylaminoantipyrine crystal;
(3) 4-formylaminoantipyrine is methylated by dimethyl sulfate under alkaline conditions, and then hydrolyzed with sulfuric acid, and neutralized to obtain 4-methylaminoantipyrine;
(4) 4-methylaminoantipyrine is obtained by condensation reaction to obtain a solution containing analgin;
(5) The solution of the step (4) is refined and crystallized to finally obtain analgin.
In the above production process, the neutralization reaction of the step (I) is carried out by cooling the hydrolyzed reaction liquid to 65-75 ° C (preferably 66 ° 〇, 681:, 701:, 721:, 74) with circulating water. °0 starts to neutralize ammonia gas, stops ammonia gas when it is neutralized to 85-88 °C, and continues to cool the reaction solution to 70-80 °C (preferably 71 °C, 73 °C, 75 °C, 78) O. 5-1. 5h, neutralized to a pH of 7. 0-7. 5 (preferably 7. 2, 7. 3, 7. 4) The other reactions in step (I) are carried out according to the existing process, so that the color of the produced 4-aminoantipyrine oil is obviously improved.
The neutralization reaction of step (I) in the prior art is to pass ammonia gas and maintain the neutralization temperature not exceeding 92 °C.
In the above production process, the step (2) is the same as the existing production process.
In the above process, the neutralization reaction of the step (3) is carried out by using sodium carbonate instead of the liquid ammonia in the original production process for neutralization, the temperature of the neutralization reaction is 70-90 ° C, the final pH is 7. 2-7. 5.
In the above production process, the 4-methylaminoantipyrine oil obtained in the step (3) is subjected to impurity removal by alcohol before the step (4). 4-methylaminoantipyrine oil is dissolved in alcohol, and the amount of Ikg 4-methylaminoantipyrine oil is taken as an example. The amount of alcohol is (O. 25-0. 30) kg, wherein inorganic salt impurities are insoluble. Alcohol, which removes some impurities.
In the above production process, the specific step of the condensation reaction in the step (4) is as follows: firstly, sodium metabisulfite and activated carbon are added to the 4-methylaminoantipyrine ethanol solution at a concentration of 33.3% to 35.7% by weight. Stir well, add formaldehyde at a reaction vessel temperature of 30-40 ° C, then reflux at 50-70 minutes at 78-82 ° C, adjust the pH of the reaction solution with sodium carbonate at reflux for 15-20 minutes. It is 7. 0-8.0; wherein the amount of each component is as follows: taking the amount of Ikg 4-methylaminoantipyrine as an example, the amount of formaldehyde is (O. 14-0. 143) kg, the amount of sodium metabisulfite 0. 4550,0. 4560,0. The amount of the amount of the sodium sulfite is preferably O. 4380, O. 4430, 0. 4480, 0. 4550, 0. 4560, 0. 4580kg; sodium thiosulfate may also be added to the 4-methylaminoantipyrine ethanol solution, the specific amount is as follows: the dosage of Ikg 4-methylaminoantipyrine is taken as an example, and the amount of sodium thiosulfate is ( O. 42-0. 77) g, that is, the amount of sodium thiosulfate per batch is O. 3-0. 5kg, wherein the amount of 4-methylaminoantipyrine per batch is 650-700 kg. Sodium thiosulfate acts as an antioxidant to prevent yellowing.
In the above production process, the refined crystallization according to the step (5) means that the reaction liquid of the step (4) is pressed into a refining crystallization tank through a pressure filter to carry out crystallization centrifugation, and after centrifugation, the anaerobic product is put into a condensation tank and alcohol is re-applied. Dissolved, wherein the weight ratio of dipyrene to alcohol is I: O. 58-0. 62, and then pressed into a refined crystallizing tank by a filter press to carry out recrystallization.
