Interox Chemicals Limited

Propylox

Propylox a Society Anonyme

Propylox a Societe Anonyme

Anthony M Hildon

Peter F Greenhalgh

Thomas D Manly

Alan J Jaggers

The invention provides a process and apparatus for liquid-liquid extraction in which a first liquid phase is passed continuously through a series of extraction stages (10) while a second liquid phase is passed continuously through the series in counter-current to the first phase. In each stage the second phase is dispersed as by a sieve plate (11) and then allowed to coalesce into a settled body (14) from which the second phase is withdrawn and passed to the next adjacent stage. The invention is characterized by the fact that the flows of the two phases in each stage are generally transverse to each other. Preferably the first phase flows through the series of stages under gravity while the second phase is pumped (16) from stage to stage to control its inter-stage transfer. The invention combines the features of separate control of residence time characteristics of an extraction column with the safety aspects inherent in a mixer/settler battery.

Preparation of peracid by liquid-liquid extraction

Epoxidation of an alkene by reaction with a peroxycarboxylic acid to produce an oxirane. A peroxycarboxylic acid in organic solution is reacted with an alkene to produce a product mixture. Unreacted alkene is separated from the product mixture as a gas. The separated alkene is absorbed into the organic solution containing the peroxycarboxylic acid. The oxirane product is obtained by purification of the product mixture after the alkene has been separated. The organic solution containing the peroxycarboxylic acid is preferably obtained by countercurrently contacting an aqueous phase which includes sulfuric acid, hydrogen peroxide and water and an organic phase containing carboxylic acid and organic solvent.

Epoxidation

The invention provides a continuous process for the production of a peracid in a chlorinated hydrocarbon solvent comprising the steps of: (a) providing an aqueous phase comprising sulphuric acid, hydrogen peroxide and water; (b) providing an organic phase comprising a chlorinated hydrocarbon solvent and carboxylic acid selected from the group consisting of acetic acid and propionic acid; and (c) contacting said aqueous and organic phases countercurrently to produce an aqueous solution comprising sulphuric acid and water and an organic product solution comprising chlorinated hydrocarbon solvent and a peracid corresponding to said carboxylic acid. Desirably the process includes the added step of: (d) utilizing at least a portion of said aqueous solution to provide at least a portion of the aqueous phase of step (a).

A process for the production of epichlorhydrin, which comprises the steps of:

The invention provides a continuous process for the production of a peracid in an organic solvent comprising the steps of: (a) providing an aqueous phase comprising sulphuric acid, hydrogen peroxide and water; (b) providing an organic phase comprising an organic solvent and carboxylic acid; and (c) contacting said aqueous and organic phases countercurrently to produce an aqueous solution comprising sulphuric acid and water and an organic product solution comprising organic solvent and a peracid corresponding to said carboxylic acid. Desirably the process includes the added step of: (d) utilizing at least a portion of said aqueous solution to provide at least a portion of the aqueous phase of step (a). The invention also provides a continuous process for the epoxidation of an alkene comprising steps (a) through (d) with the added steps of: (e) reacting at least a portion of the peracid of said organic solution and an alkene to produce a product mixture comprising oxirane, carboxylic acid and organic solvent; (f) effecting distillation of said product mixture to produce a product phase comprising the oxirane and a recycle phase comprising carboxylic acid and organic solvent; and (g) utilizing at least a portion of said recycle phase to form at least a portion of the organic phase of step (b).

Production of a peracid and an oxirane

The invention provides a continuous process for the preparation of a peracid which comprises reacting hydrogen peroxide with a carboxylic acid in an aqueous medium containing a mineral acid, and extracting the peracid thus formed into an organic phase comprising an organic solvent so as to produce an aqueous solution comprising sulphuric acid and water and an organic solution comprising peracid and organic solvent, wherein the hydrogen peroxide is added to the reaction mixture in a plurality of stages, thereby to limit the concentration of hydrogen peroxide at any location. Preferably the reaction and extraction are effected simultaneously.

The invention provides a process for epoxidation of an alkene by reaction with a peracid, characterized by supplying an aqueous phase comprising sulphuric acid, hydrogen peroxide and water and an organic phase comprising acetic acid or propionic acid in a chlorinated hydrocarbon solvent to a liquid-liquid extraction device in such manner that these two phases pass in countercurrent through the extraction device; withdrawing from such extraction device an organic solution of peracid and carboxylic acid in the chlorinated hydrocarbon; passing said organic solution and the alkene cocurrently to a reactor; withdrawing from the reactor a product mixture and effecting fractional distillation thereof; withdrawing from such fractional distillation a product phase comprising the oxirane and a recycle phase comprising carboxylic acid in the chlorinated hydrocarbon, and passing such recycle phase from the distillation to the extraction device to form the organic phase therein. The importance of the invention resides in the integration of the epoxidation step with that of the manufacture of the peracid, and in the fact that the carboxylic acid, sulphuric acid and chlorinated hydrocarbon solvent are all recycled.

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Tattenhall, United Kingdom

Anthony M Hildon