Basf Aktiengesellschaft

Basf Se Corporation

Michael Mauss

Dieter Baumann

Alexander Wissemeier

Matthias Rauls

Ralf-Thomas Rahn

Michael Bock

Wolfram Zerulla

Gregor Pasda

Oliver Huttenloch

Wolfgang Weigelt

Holger Ganz

Dieter Schlafer

Patrick Deck

Wolfgang Körnig

A process for the removal of acids from reaction mixtures, comprising at least one product of value which is sparingly soluble in water, by at least one unpolar amine as an auxiliary base, which includes: a) reacting the auxiliary base with the acid with formation of a salt; b) reacting the salt formed in step a) with a further base which accepts the acid with liberation of the auxiliary base and combines with the acid to be accepted from the auxiliary base to form a salt which is very readily soluble in water; c) extraction of the mixture obtained in step b) with water or an aqueous medium, wherein the salt of the further base dissolves in the aqueous phase and the product of value, or the solution of the product of value, in a suitable solvent and the auxiliary base form at least one separate nonaqueous phase; and d) removal by distillation of at least part of any solvent present from the at least one nonaqueous phase obtained in step c), to form two nonmiscible liquid phases.

Method of separating acids from chemical reaction mixtures by means of apolar amines

In a process for preparing crystalline NaOH.3.5H.sub.2 O, NaOH.3.5H.sub.2 O is allowed to crystallize from an aqueous sodium hydroxide solution which contains sodium chloride and is saturated in respect of NaOH.3.5H.sub.2 O and the crystals formed are separated from the solution using a mechanical solid/liquid separation apparatus, wherein the solid/liquid separation is carried out under conditions under which the crystalline NaOH.3.5H.sub.2 O is freed sufficiently of residual solution adhering to the surface for the sodium chloride content of the crystalline NaOH.3.5H.sub.2 O obtained to be less than 100 mg per kg. The crystalline NaOH.3.5H.sub.2 O is subjected to an additional purification step, which may include the at least superficial melting or the at least superficial dissolution of the crystals, in combination with a solid/liquid separation step. The additional purification step. The additional purification step comprises washing the crystalline NaOH.3.5H.sub.2 O separated off.

Purification of caustic soda

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Neustadt, Germany

Michael Mauss