Process for the preparation of propylene oxide

USRE30945E · kind E · reissue

Assignees

• BAYER HEALTHCARE LLC · DE
• Deutsche Gold- und Silber-Scheideanstalt Vormals Roessler

Inventors

• Guter Prescher · Hanau, DE
• Gerd Schreyer
• Otto Weiberg
• Rolf Wirthwein · Hanau, DE
• Helmut Waldmann · Leverkusen, DE
• Hermann Seifert · Bensberg, DE
• Wulf Schwerdtel
• Wolf Swodenk · Odenthal, DE

Key dates

• Filing date: Feb 14, 1980
• Grant date: May 25, 1982
• Expiry date: Feb 14, 2000

Classification

• Technology area (CPC —): General

Abstract

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.