GB431313A - A process for concentrating organic carboxylic acids - Google Patents

Abstract

Organic carboxylic acids such as formic, acetic, propionic, butyric and lactic acids are concentrated by means of mixed aliphatic ethers which may contain primary, secondary or tertiary alkyl groups, a large number of such ethers being mentioned. The ethers may be used as extracting agents or may be distilled with the aqueous acids so as to carry off the water as azeotropic mixtures. Usually it is preferred to use an ether of lower boiling-point than the acid to be concentrated. The acid may be extracted in counter-current in a tower, and the ether may be injected under pressure through a small orifice, or the dispersion may be effected by other means; or the acid may be dispersed in the solvent. The ethers may be employed in admixture with other solvents such as hydrocarbons (pentane, hexane, light naphthas and the like) and/or esters. If the organic acid to be concentrated contains mineral acid, this should be removed for instance by treatment with barium oxide, carbonate or acetate in the case of sulphuric acid or, silver acetate in the case of hydrochloric acid.ALSO:Organic carboxylic acids are concentrated by means of mixed aliphatic ethers which may contain primary, secondary, or tertiary alkyl groups, a large number of such ethers being mentioned. The ethers may be distilled with the aqueous acids so as to carry off the water as azeotropic mixtures. Usually it is preferred to use ethers of lower boiling-point than the acids to be concentrated. The ethers may be employed in admixture with other solvents such as hydrocarbons (pentane, hexane, light naphthas and the like) and/or esters. If the organic acid contains mineral acid, this should be removed, for instance by treatment with barium oxide, carbonate or acetate in the case of sulphuric acid, or silver acetate in the case of hydrochloric acid.