- Apr 08, 2018 -
Purification method: The crude 20% acetyl acetone was dissolved in 80% benzene and then shaken with an equal volume of distilled water for 3 hours. The water-soluble acetic acid was partitioned into the aqueous phase, while acetylacetone was dissolved in benzene. Benzene was distilled off and purified to give acetylacetone.
1. Acetone and acetic anhydride condensation law The reaction formula is as follows: This route is simple, mature, and high yield. However, boron trifluoride is a dangerous gas, which is inconvenient to use and waste liquids are difficult to handle. 2. Ethyl acetate-acetone method The reaction formula is as follows: This method is a classical synthesis method. The process requires the use of sodium metal, which brings certain risks to industrial production. 3. Acetyl acetate acetic anhydride acetic anhydride method The reaction formula is as follows: The process is simple, convenient, equipment investment is small, but its technical and economic indicators are not ideal, the cost of raw materials is equivalent to the price of imported products. 4. Ethylacetoacetone ketene method The reaction formula is as follows:
This method has mild reaction conditions and high yield. However, long process flow, high raw material prices, and large investment. 5. Ketone-acetone condensation conversion method The reaction formula is as follows: 6. Acetone-ethyl acetate method The reaction formula is as follows:
7. Mix the excess refined ethyl acetate with dry acetone, cool to below 0°C, slowly add the powdered sodium amide with stirring, start the reaction, and release a large amount of ammonia:
Under cooling with ice water, the reaction was stirred for 24 hours and allowed to stand at room temperature overnight. Then add the same amount of ice and water, stand for stratification, take the water layer, neutralize to acidity with dilute sulfuric acid. Add an appropriate amount of saturated copper acetate solution to precipitate acetylacetone to form a chelate. After precipitation is sufficient, the mixture is filtered off with suction, washed twice with water, transferred to ether and shaken sufficiently, and 2 mol/L of sulfuric acid is added to decompose the chelate. After standing, the ether layer was separated, the acid layer was extracted once with ether, and the ether layers were combined. Anhydrous calcium chloride was added to dry and dehydrated. Filtration, distillation, recovery of distillate ether, collection of 125-140° C. fraction, second distillation, Collect 135 to 140 °C fractions, which are finished products.