Bayer Aktiengesellschaft

Deutsche Gold- Und Silber-scheideanstalt Vormals Roessler

Degussa Aktiengesellschaft

Henkel Kgaa

Degussa Atiengesellschaft

Rolf Wirthwein

Helmut Waldmann

Gerd Schreyer

Hermann Seifert

Wulf Schwerdtel

Willi Hofen

Gunter Prescher

Wolfgang Swodenk

Otto Weiberg

Herbert Klenk

Jorg Krekel

Gerd Siekmann

Karl-Hermann Reissinger

Karlheinz Drauz

Axel Kleemann

Reinhard Stober

The production of organic hydrogen peroxide solutions which are practically water-free until now has had the problem of either too high a water content of the solution or too great a loss of hydrogen peroxide through decomposition and passing over as distillate during the distillative drying. By selection of specific esters in combination with commensurately high pressures in the azeotropic removal of water, these disadvantages can be avoided. Extremely low water content solutions of hydrogen peroxide in high boiling solutions are produced by mixing hydrogen peroxide solutions in solvents whose azeotropic boiling point with water is below the boiling point of hydrogen peroxide with higher boiling solvents which form the highest azeotrope with water, whose boiling point is near or above the boiling point of hydrogen peroxide. Thereupon, the mixture is freed from both water and the lower boiling solvent. The mixture can be formed by an in situ method. Production of extremely low water containing solutions of hydrogen peroxide in high boiling solvents are produced by mixing hydrogen peroxide solutions in solvents whose azeotrope boiling point with water is below the boiling point of hydrogen peroxide with higher boiling solvents which form the highest azeotrope with water, whose boiling point is near or above the boiling point of hydrogen peroxide. Thereupon, the mixture is freed from both water and the lower boiling solvent. The above-mentioned mixture can also be produced by an in situ method.

Process for the production of water-free organic hydrogen peroxide

A process has been developed for the purification of expoxides containing carbonyl compounds as impurities wherein the carbonyl compound content is up to 2% by weight of epoxide. Purification is effected by treatment with compounds containing at least one NH.sub.2 group.

Process for the purification of epoxides

Caprolactones such as .epsilon.-caprolactone are stabilized against discoloration with dihydroxybenzenes such as hydroquinone or compounds of the formula ##STR1## in which R.sub.1 is alkyl of 1 to 8 carbon atoms, and

Stabilizing caprolactones with dihydroxybenzenes

The invention relates to a process for the production of .epsilon.-caprolactone having a purity of 99.9% and increased color and storage stability which comprises feeding .epsilon.-caprolactone, which has been made by reacting cyclohexanone with a solution of a percarboxylic acid, into a first distillation unit, operating at 0.1 to 500 mbars and drawing off as the top product a mixture consisting of .epsilon.-caprolactone and lower-boiling impurities, feeding the bottom product of said first distillation unit into a second distillation unit, operating at 0.1 to 500 mbars and then drawing off the pure .epsilon.-caprolactone as the top product. The .epsilon.-caprolactone is useful as an intermediate for the production of known useful compounds such as polyesterols which are subsequently converted to polyurethanes.

Process for the manufacture of very pure .epsilon.-caprolactone

Aromatic peroxycarboxylic acids are produced by reacting aromatic carboxylic acids with hydrogen peroxide in the presence of sulfuric acid by having a mixture of aqueous 50-99 weight % H.sub.2 O.sub.2 and sulfuric acid present in the reaction vessel, introducing the solid aromatic carboxylic acid with stirring, the reaction being carried out in heterogeneous phase, the stirring being continued to the end of the reaction and then the reaction mixture obtained worked up in known manner.

Process for the production of aromatic peroxycarboxylic acids

Process for isolating propylene glycol diacarboxylates in the preparation of propylene oxide by reaction of propylene with a solution of percarboxylic acid in an organic solvent, the boiling point of which is lower than that of the carboxylic acid which corresponds to the percarboxylic acid used as the epoxidizing agent, and higher than that of propylene oxide, separation, by distillation, of the reaction mixture which essentially contains propylene oxide, the carboxylic acid corresponding to the percarboxylic acid used as the epoxidizing agent and one or more of the by-products propyleneglycol, propylene glycol monocarboxylate and propylene glycol dicarboxylate as well as propylene and the organic solvent, into a fraction containing propylene oxide and propylene and a fraction containing the carboxylic acid, the by-products mentioned and the organic solvent and further separation of the fractions into the individual components by distillation. The fraction containing the carboxylic acid, one or more of the by-products propylene glycol, propylene glycol monocarboxylate and propylene glycol dicarboxylate, and the organic solvent is distilled in a column at pressures of 1.5 to 6 bars and with an average residence time of 10 to 90 minutes in the sump. The organic solvent is removed as the top product and the carboxylic acid and the corresponding propylene glycol dicarboxylate is obtained as the sump product. From the sump product the propylene glycol dicarboxylate is isolated in a manner which is in itself known.

Process for isolating propylene glycol diesters in the preparation of

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, 18) and following drying of the benzene solution (21), the perpropionic acid in the solution is reacted with propylene (24) 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 (30, 32, 37, 39), and the latter two are recycled. In the benzene extraction (5, 18), an aqueous raffinate (7) is formed containing hydrogen peroxide and acid catalyst. The aqueous raffinate can be divided into a stream which is recycled to the propionic acid reactor (1), and a second stream which can be distilled to remove water with the concentrate being recycled to the propionic acid reactor. (1)

Process for the preparation of propylene oxide

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.

Process for continuous production of substantially anhydrous solutions of percarboxylic acid in solvent. Aqueous hydrogen peroxide is first reacted with the corresponding carboxylic acid in the presence of acid catalyst to form percarboxylic acid and water (1). The percarboxylic acid is extracted with solvent (5), to provide a solvent phase containing the percarboxylic acid (11) and an aqueous raffinate (7). The solvent phase is subjected to distillation (12) to provide the anhydrous solution (13). In this distillation (12) the hydrogen peroxide remaining in the solvent phase produced in the extraction (5), is distilled off together with water and some solvent, and the hydrogen peroxide is recovered as an aqueous phase and recycled (14). The aqueous raffinate, which contains hydrogen peroxide, is distilled to remove water (8) and the resulting concentrate is recycled (2) for use in the reaction (1).

Process for the preparation of percarboxylic acid solutions

Process for separating a solution, which essentially contains propylene oxide, propylene, a carboxylic acid containing 1 to 4 carbon atoms and benzene, by distillation. The solution is fed to a first distillation stage in which propylene, propylene oxide and an amount of the benzene contained in the solution such that the top product from this first distillation contains 20 to 70% by weight of benzene are distilled off over the top at a pressure of 1.0 to 2.5 bars, and in which the carboxylic acid and the remaining benzene are obtained as the sump product. The top product from the first distillation is fed to a second distillation column in which propylene and possibly present small fractions of components which boil lower than propylene oxide are distilled off over the top and a sump product which essentially consists of propylene oxide and benzene is obtained and part of this is returned as reflux to the first distillation column.

Process for separating solutions containing propylene oxide

Process for continuous production of substantially anhydrous solutions of perpropionic acid in benzene. Aqueous hydrogen peroxide is first reacted with propionic acid in the presence of acid catalyst to form perpropionic acid and water (1). The perpropionic acid is extracted with benzene (5), to provide a benzene phase containing the perpropionic acid (11) and an aqueous raffinate (7). The benzene phase is subjected to an extraction with water (12) involving at least 3 stages, to remove hydrogen peroxide, and the resulting benzene extract (15) is subjected to azeotropic distillation (26) to provide the anhydrous solution (17). The aqueous raffinate, which contains hydrogen peroxide, is distilled to remove water (8) and the resulting concentrate is recycled (2) for use in the reaction (1).

Growing community of inventors

Hanau, Germany

Rolf Wirthwein