| 摘要 |
Peracids of lower, saturated aliphatic carboxylic acids having from 1-3 C atoms are made by reacting hydrogen peroxide with the corresponding aliphatic acid in the ratio 0.3 to 5.0 moles hydrogen peroxide/mole of acid at 20-80 DEG C. in a reaction mixture containing 5-20% by weight of a strong, water-entraining acid, and 20-75% by weight of water and vaporizing together from the reaction mixture, at a pressure of 15-350 mm. of mercury, and a temperature of 20 to 80 DEG C. a product containing peracid, aliphatic acid and water. The process may be operated batchwise or continuously. In the continuous process the hydrogen peroxide, aliphatic acid and water, are continuously added to the reaction mixture, the hydrogen peroxide and lower aliphatic acid being added in the proportions of 0.30 to 1.1 mole hydrogen peroxide/mole acid, the concentrations of water and water-entraining acid being maintained at 20-75% and 5-20% respectively. The reaction is carried out at a pressure of 15-350 mm. of mercury, and the product is continuously distilled off. The reaction will normally take place in 10 minutes to 1 hour, preferably 10 to 30 minutes. Suitable water-entraining acid substances are sulphuric acid and other strong acids which boil above 150 DEG C. at atmospheric acid, and alkyl and aryl sulphonic acids, trifluoroacetic acid, and cation-exchange resins, e.g. sulphonated styrene-divinylbenzene copolymers. Sodium sulphate, molybdenum sulphate or calcium sulphate together with a strong acid which boils above 150 DEG C. may also be used. The hydrogen peroxide is normally introduced as an aqueous solution and may be used in a concentration of 20-100%. Comparative examples are given in which 1% sulphuric acid is used as water-entraining acid. |
