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Consortium Fur Elektrochemische Industrie Gmbh

Consortium F&uuml;r Elektrochemische Industrie Gmbh

Michael Hallmann

Harald Voit

Christoph R&uuml;dinger

Mehmet G&uuml;naltay

Hans-Juergen Eberle

Christoph Ruedinger

Hans-J&uuml;rgen Eberle

Barbara Geborene Ne&eacute; Reil Wild

Hans J&uuml;rgen Eberle

Barbara Reil

The invention relates to a method for separating and purifying an aqueous mixture that mainly consists of acetic acid, formic acid and high-boiling substances by extraction with a solvent in a cyclic process. The inventive method is characterized in that the flow of raffinate is fed to a solvent stripping column ( ) with the major part of the water in order to remove the water from the cycle. The flow of extract is fed to a solvent recovery distillation column ( ). In a first step, a mixture (A) that consists of water and solvent, is separated by overhead distillation. A mixture (B) that consists of acetic acid, formic acid and high-boiling substances is separated via a sump. Once the formic acid is removed in a column ( ), mixture (B) is separated in an acetic acid distillation column to give pure acetic acid and high-boiling substances. Mixture (A) is fed to a phase separator and the aqueous phase is returned to the solvent stripping column ( ) together with any residual portions of the solvent while the organic phase is returned to the extractor ( ).

Method for separating and purifying an aqueous mixture that mainly consists of acetic acid and formic acid

A method for the separation and purification of an aqueous mixture of main components, namely acetic acid and formic acid and non-volatiles by extraction, uses a solvent in a circulatory system. A raffinate stream is mixed with the larger proportion of water from a solvent stripper column ( ) for the removal of water. The extraction stream is introduced into a solvent distillation column ( ), from which in a first step involving the use of a mixture (A) containing a larger proportion of the solvent is separated out via a header and a mixture (B) of formic acid, water and solvent is separated out via a side offtake and a mixture (C) of acetic acid and non-volatiles is also separated out. A mixture (B) is introduced into a formic acid distillation column ( ) for further processing, and a mixture (C) is introduced into an acetic acid distillation column ( ), and purified acetic acid is subsequently isolated in the acetic acid distillation column ( ) from the header. Pure formic acid is isolated at the settling basin of the formic acid distillation column ( ).

Method for the separation of and purification of an aqueous mixture consisting of the main components acetic acid and formic acid

A process and an apparatus are for preparing saturated carboxylic acids having from one to four carbon atoms by gas-phase oxidation at a reaction temperature of from 100&deg; C. to 400&deg; C. and pressures of from 1.2&times;10,to 51&times;10,Pa in the presence of saturated or unsaturated C,-hydrocarbons and mixtures thereof. Also present in the reactor are an oxygen-containing gas and water vapor and in the presence of at least one catalyst, with part of the reactor outlet gas being recirculated in a reaction gas circuit. The acid concentration in the recirculated portion is reduced by means of a separation step, and the crude acid is separated from the reactor outlet gas by means of a countercurrent scrubber.

Process and apparatus for preparing saturated carboxylic acids having one to four carbon atoms

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Hochburg-Ach, Austria

Michael Hallmann