FREMGANGSMAATE TIL FREMSTILLING AV PROPYLENOKSYD

摘要

Process for continuous production of propylene oxide (FIG. 1) from propylene and aqueous hydrogen peroxide. The aqueous hydrogen peroxide is first reacted with propionic acid in the presence of acid catalyst to form perpropionic acid (1). The perpropionic acid is taken up by extraction in benzene (5 , 12), and following drying of the benzene solution (16), the perpropionic acid in the solution is reacted with propylene (18) for oxidation of the propylene to propylene oxide and conversion of the perpropionic acid back to propionic acid. The reaction mixture is worked up to separate propylene oxide, propionic acid and benzene (25, 27, 31, 33), and the latter two are recycled. In the benzene extraction (5, 12), an aqueous raffinate (7) is formed containing hydrogen peroxide and acid catalyst. Water is removed from the aqueous raffinate (8) and the concentrate is recycled to the propionic acid reactor. Make-up hydrogen peroxide can be added to the aqueous raffinate before the removal of water.