Acetone (Acetone)

It is mainly used as solvent in explosive, plastic, rubber, fiber, leather making, grease, spray paint and other industries, and can also be used as synthetic ketene, acetic anhydride, iodoform, Polyisoprene Rubber, methacrylic acid, methyl ester, important raw materials of chloroform, epoxy resin and other substances. In the precision copper tube manufacturing industry, acetone is often used to wipe the black ink on the copper tube. Acetone is a good organic solvent and is widely used in industrial or experimental extraction of some organic substances, such as fruits and vegetables, food, feed, the detection of pesticide residues in tea is used to extract the organic pesticide components inside, and it is often used together with other organic solvents, such as n-hexane, to improve its extraction effect.

There are many production methods of acetone. The ancient method is to use lime to neutralize wood vinegar obtained from wood carbonization, make calcium acetate, and then produce acetone through thermal decomposition. The methods of synthesizing acetone studied in industry include: (1) calcium acetate is obtained from acetic acid and then decomposed to generate acetone; (2) Acetylene reacts with water vapor on zinc oxide catalyst to generate acetone; (3) ethanol vapor in the presence of zinc chromate catalyst, high temperature reaction to generate acetone; (4) oxidation of liquefied natural gas or naphtha to acetone (oxidation products also include Formaldehyde, Acetic Acid, butyl alcohol, etc.); (5) isopropyl alcohol oxidation or dehydration to acetone; (6) isopropyl alcohol hydrogen peroxide method acetone; (7) synthesis of acetone from isopropyl alcohol and acrolein; (8) isopropyl benzene method acetone, co-production of phenol using propylene and benzene as raw materials, through the hydrocarbon to produce isopropyl benzene, and then air oxidation to obtain isopropyl hydrogen peroxide, and then decomposition with sulfuric acid or resin, acetone and phenol are obtained at the same time; (9) the process route of direct oxidation of propylene to acetone is similar to that of direct oxidation of ethylene to acetaldehyde; (10) P-methyl isopropylbenzene hydrogen peroxide production p-cresol, by-product acetone; (11) hydroquinone is produced by diisopropylbenzene method, and acetone is by-product. However, there are not many methods actually adopted in industry. At present, acetone produced by grain fermentation still accounts for a large proportion in our country. Cumene method is the main method in synthesis. The mixture of acetone, butyl alcohol and ethanol is produced by fermentation of agricultural and sideline products containing starch. The ratio of the three is acetone: butyl alcohol: ethanol = 32:56:12 to 25:70:3 (weight ratio). For each production of 1T acetone, about 11T starch or 60-66t waste molasses is consumed. Cumene method is the most economical method in acetone production route, and phenol is obtained at the same time. The ratio of the two is Phenol: acetone = 1:0.6 (weight). Based on phenol, the 100,000 t-level unit consumes 590kg of propylene (90%) per ton of phenol. Refining method: due to different manufacturing methods, the impurities contained are also different. The main impurities include water, alcohol, aldehyde, ether and trace acidic substances. When refining, anhydrous calcium sulfate, potassium carbonate and molecular sieve are generally used for dehydration and distillation. If aldehyde and other reducing substances are to be removed, a small amount of potassium permanganate can be added to reflux in batches until the purple color does not disappear, and then anhydrous calcium sulfate or potassium carbonate can be dried and rectified; Alkaline silver nitrate solution can also be used to interact with acetone, filtered, dried and distilled to remove organic impurities. To obtain high-purity acetone, acetone can interact with sodium bisulfite to filter out the generated addition compound product. After washing, ether will be decomposed with sodium carbonate solution, and anhydrous potassium carbonate will be dried and distilled. You can also use sodium iodide to react with acetone, filter out crystals, and remove pure acetone immediately after heating. The specific operation is as follows: ① in 1000ml acetone, 30ml of water dissolved with 4g of silver nitrate and 30ml of 1mol/L sodium hydroxide solution are added. After stirring for 10 minutes, it is filtered, dried with anhydrous calcium sulfate and distilled. ② add powdered potassium permanganate in acetone in batches and heat it to reflux until the purple color does not disappear. Then anhydrous calcium sulfate was added to dry, filtered and fractionated. This method is suitable for refining large amounts of acetone. ③ add 100g of powdered sodium iodide to 440g of boiling acetone, cool to-8℃ with ice salt, and precipitate the adduct of sodium iodide and acetone (NaI · 3C3H6O). After filtering, it is moved into the distillation flask, and the pure acetone can be separated by a little heating. Sodium iodide can be reused. Acetone is dehydrated and condensed under the action of acid or alkali. Therefore, it is difficult to obtain anhydrous substances. The above reaction can also occur when calcium chloride, phosphorus pentoxide, silica gel, alumina gel, sodium sulfate and potassium carbonate are dehydrated, so anhydrous calcium sulfate or magnesium sulfate is better as desiccant. (11) the main impurities of industrial acetone are water, aldehyde, alcohol and other organic substances. It can be dehydrated with burnt potassium carbonate, anhydrous calcium chloride or 4A molecular sieve, and then added with 12% silver nitrate solution (34ml per liter of acetone) add 1mol/L sodium hydroxide solution (30ml per liter of acetone). After sufficient oscillation, it is allowed to stand, and the filtrate obtained after filtration is dehydrated and dried with anhydrous calcium sulfate; If it contains reducing organic impurities, powdered potassium permanganate can be added in batches to acetone in a small amount, and the filtrate can be refluxed while heating, until the generated purple color does not fade, steam out the acetone and dehydrate and dry it. Finally, under normal pressure, the heating temperature is controlled to 65 ~ 70℃ for distillation, and 55 ~ 57℃ fraction is collected, which is the finished product.