GB445108A - Improvements in the recovery of acidic and basic reagents - Google Patents

Abstract

Volatile organic acids and volatile bases are recovered from their salts with one another by heating the salts in presence of a substance non-volatile under the conditions employed and which forms with the organic acid a compound which is stable under the conditions necessary for distilling off the base. The process is described with reference to ammonium acetate, but is also applicable to aliphatic amine acetates and to propionates, butyrates, &c. of methylamines, ethylamines, ethylene diamine and other volatile bases. Ammonia and acetic acid may be recovered by distillation of ammonium acetate solution with sodium or potassium acetate or both, the mixtures facilitating the recovery of the acid owing to their ready fusibility; and inert substances which reduce the melting point may also be added. The acetic acid may be recovered by continuing the distillation after the removal of the ammonia, or may be extracted with a suitable solvent. The process may be effected as described in Specification 439,764, the ammonium acetate solution being fed in to the heated sodium acetate at such rate that the mixture remains at all stages substantially dry. In an example, a solution containing ammonium, sodium, and potassium acetates is distilled until the temperature reaches 150 DEG C. to remove ammonia, and the distillation is continued under vacuum until the temperature reaches 250 DEG C. to remove acetic acid. The acid distillate is fractionated, the residue, which is chiefly acetamide, being added to the acetates left in the first distillation and used again. Specification 436,224 also is referred to.ALSO:Volatile organic acids and volatile bases are recovered from their salts with one another by heating the salts in presence of a substance non-volatile under the conditions employed and which forms with the organic acid a compound which is stable under the conditions necessary for distilling off the base. The process is described with reference to ammonium acetate, Ammonia and acetic acid may be recovered by distillation of ammonium acetate solution with sodium or potassium acetate or both, the mixtures facilitating the recovery of the acid owing to their ready fusibility; and inert substances which reduce the melting point may also be added. The acetic acid may be recovered by continuing the distillation after the removal of the ammonia or may be extracted with a suitable solvent. The process may be effected as described in Specification 439,764, [Group IV], the ammonium acetate solution being fed on to the heated sodium acetate at such rate that the mixture remains at all stages substantially dry. In an example, a solution containing ammonium, sodium, and potassium acetates is distilled until the temperature reaches 150 DEG C. to remove ammonia, and the distillation is continued under vacuum until the temperature reached 250 DEG C. to remove acetic acid. The acid distillate is fractionated, the residue which is chiefly acetamide, being added to the acetates left in the first distillation and used again. Specification 436,224 also is referred to.