Process for the preparation of organic solutions of percarboxylic acids

Abstract

Abstract A process for the continuous preparation of organic solutions of percarboxylic acids by reaction of an aqueous solution of hydrogen peroxide with the corresponding carboxylic acid in the presence of an acid, water-soluble catalyst which boils above 160° C., extraction of the percarboxylic acid from the resulting reaction mixture using an organic solvent which is immiscible with water, reconcentration of the raffinate, which essentially contains hydrogen peroxide and the acid catalyst, by distilling off water in a distillation column and recycle of the raffinate, concentrated in this way, into the reaction with the carboxylic acid. The raffinate is divided into two partial streams in a ratio of 1 to 25:1. The raffinate is fed to a distillation column which is operated under reduced pressure and which has at least two take-off weirs as tray inserts, the first take-off weir being at least two theoretical plates above the sump phase, the second take-off weir being arranged at least two theoretical plates above the first take-off weir and the section of column between the second take-off weir and the top of the column having at least two theoretical plates. The larger partial stream of the raffinate is passed into the column below the first take-off weir and the smaller partial stream is passed into the column below the second take-off weir. Water is removed at the top of the distillation column. A first side stream, which essentially contains the hydrogen peroxide from the small partial stream of the raffinate from the extraction, is withdrawn from the second take-off weir and is a 2 to 40% strength by weight aqueous solution of hydrogen peroxide, which is optionally fed, together with the larger partial stream of the raffinate from the extraction, into the column below the first take-off weir. A second side stream is withdrawn from the first take-off weir and is an aqueous solution of the acid catalyst which optionally can be further worked up and re-used. The re-concentrated aqueous solution of hydrogen peroxide and acid catalyst, withdrawn as a sump product from the distillation, is recycled into the reaction with carboxylic acid. A third side stream can be taken from a third take-off weir which is arranged not more than 2 theoretical plates below the first take-off weir. The following applications are related to the process hereof for production of propylene oxide as being directed to aspects of the process, some of which are disclosed herein. ______________________________________ German Serial U.S. Atty's Docket U.S. Serial No. No. No. ______________________________________ P 25 19 288.5 Bayer 2883 678,819 P 25 19 300.4 Bayer 2884 678,820 P 25 19 299.8 Bayer 2885 678,821 P 25 19 298.7-42 Bayer 2886 678,822 P 25 19 297.6 Bayer 2887 678,823 P 25 19 295.4 Bayer 2888 678,824 P 25 19 292.1-42 Bayer 2890 678,826 P 25 19 291.0-42 Bayer 2891 678,827 P 25 19 289.6 Bayer 2892 678,828 P 25 19 297.4 Bayer 2893 678,829 ______________________________________ All of the German applications were filed Apr. 30, 1975. Those applications are incorporated herein by reference.

Inventors

• 👤 Willi Hofen
• 👤 Gunter Prescher
• 👤 Gerd Siekmann
• 👤 Gunter Wolf

Bibliographic Details