Melting point: 132-135℃ (lit.)
Boiling point: 228℃
Density: 1.2 g/cm3 at 20℃
Vapor pressure: 0.01 mm Hg (20℃)
Sorbic acid, also known as sorbic acid, is an acidic preservative used in foods currently allowed in my country, and it is also the most widely used high-efficiency non-toxic food antifungal agent in the world. The structural formula CH3CH=CH—CH=CHCOOH. The molecular formula is C6H8O2 and the relative molecular mass is 112.12. Colorless needle-like crystal or white crystalline powder; stable to light and heat, but easy to oxidize and change color; melting point 134.5℃, boiling point 228℃ (decomposition); pH value of saturated aqueous solution is 3.6; slightly soluble in water, easily soluble It is soluble in methanol, ethanol, glacial acetic acid, acetone, soluble in acetone, benzene, and carbon tetrachloride, showing a sour taste and non-toxic. It is chemically active and easy to undergo addition reactions to produce saturated compounds.
1. Widely used in food, beverage, pickles, tobacco, medicine, cosmetics, agricultural products and other industries. It is also used in the preparation of preservatives, antifungal agents, insecticides and the synthetic rubber industry. Inhibitor of molds and yeasts. Food antifungal agent. Dry oil denaturant. Fungicide.
2. Sorbic acid and potassium sorbate are the most widely used preservatives in the world. They have high antibacterial properties and inhibit the growth and reproduction of molds. By inhibiting the dehydrogenase system in the microorganisms, they can inhibit the growth of microorganisms and play an antiseptic effect. It has inhibitory effect on molds, yeasts and many aerobic bacteria, but it is almost ineffective on anaerobic spore forming bacteria and Lactobacillus acidophilus. It is widely used in the preservative of various cheese products such as cheese and yogurt, bread and snack products, beverages, fruit juices, jams, pickles and fish products. The amount of concentrated fruit and vegetable juice in plastic barrels shall not exceed 2g/kg; the maximum amount used in soy sauce, vinegar, jams, hydrogenated vegetable oil, soft candy, dried fish products, instant soy products, pastry fillings, bread, cakes, moon cakes is 1.0 g/kg; in wine and fruit wine, the maximum use amount is 0.8g/kg; in collagen casings, low-salt pickles, sauces, candied fruit, fruit juice (flavor) beverages and jelly, the maximum use amount is 0.5g/kg; in fruits and vegetables The maximum use amount in the fresh-keeping and carbonated beverages is 0.2g/kg; in the food industry, it can be used in meat, fish, eggs, and poultry products with a maximum use amount of 0.075g/kg.
3. Used in detergents, cosmetics, feed, medicine, etc.
1. The ketene method This method is a more commonly used method for industrial production in the world. Acetic acid is cracked at high temperature to generate ketene, and then it is condensed with crotonaldehyde to form polyester, which is then hydrolyzed and refined to obtain the finished product. Raw material consumption quota: ketene 510kg/t, crotonaldehyde 1100kg/t.
2. The malonic acid method is derived from the condensation and decarboxylation of malonic acid and crotonaldehyde.
3. The acetone method is obtained by the condensation of acetone and crotonaldehyde, followed by dehydrogenation.
4. The butadiene method uses butadiene and acetic acid as raw materials, in the presence of a manganese acetate catalyst, and compressed at 140°C to obtain γ-ethylene-γ-butyrolactone. Butyrolactone is ring-opened to obtain sorbic acid under the action of acidic ion exchange resin.
5. Acetic acid is pyrolyzed to generate ketene, and then condensed with crotonaldehyde to form polyester, and then hydrolyzed and refined to obtain the finished product.
6. Tobacco: OR, 44; OR, 26. At 0ºC, crotonaldehyde and ketene are reacted under the catalysis of boron trifluoride; or 2-crotonaldehyde and malonic acid are prepared by heating in the presence of pyridine.