| 摘要 |
<p>Gaseous hydrogen chloride is extracted from dilute aqueous hydrochloric acid using amines, by extracting the aqueous hydrochloric acid with an amine or with a mixture of an amine and an inert, water-immiscible solvent having a boiling point of at least 120.degree.C. The amine is a tertiary alkyl-amine containing 14 to 36 carbon atoms in the nitrogen-bound side chains, the side chains having at most one nitrogen-bound metbyl group and at least one nitrogen-bound aliphatic group containine at least 6 carbon atoms, the amine acid constant being less than 10-3. An inert, water-immiscible solvent having a boiling point of at least 120.degree.C is then added to the extract, unless the solvent was already added in the first stage. The extract is distilled, the vapors generated are condensed and water is continuously separated from the two-phase condensate and the organic phase fed back into the distillation procedure. An aminohydrochloride cleavage step is carried out by distilling the extract at reflux after removing the water and evacuating the gaseous hydrogen chloride released at the head of the column or by separating the hydrogen chloride from the extract after removing the water at less than the boiling point of the solvent by passing an inert gas flow therethrough. The solvent containing the amine is fed back into the extracting procedure and carboxylic acid chloride is added at least in stoichiometric quantity referred to the primary and secondary amines formed from thermal dissociation of the alkylamines, solvent and any impurities.</p> |
