REMOVAL OF ALDEHYDES BY AMINO-ACIDS AND THEIR SALTS IN AMBIENT AIR

The removal of gaseous aldehydes by amino acids and by their sodium sa lts and hydrochlorides was studied in ambient air with the relative hu midity of 30 % at 25-degrees-C. Amino acid sodium salts, diamino acids , sodium p-aminobenzoate (PABANa), and o-aminobenzoate (OABANa), and p -aminobenzoic acid (PABA) on sepiolite, both having a carboxylato func tionality (-COO-) together with an amino (-NH2) group, were highly rea ctive with aldehydes. In contrast, PABA which has free carboxylic acid functionality (-COOH: dimeric) was not so reactive with aldehydes. No rmal amino acids and their hydrochlorides having ammonio (-NH3+) and - COO- or -COOH (dimeric) groups were less reactive with aldehydes. The reactivity was closely related to the degree of dissociation of carbox ylate anion; as the degree of dissociation increases, the compound bec omes more reactive. p-Aminobenzoic acid hydrochloride (PABA . HCI), ha ving -NH3+ and -COOH (monomeric) groups, was the most reactive (with e thanal) of all the amino acids and their salts examined. Amino acid so dium salts, diamino acid, PABANa, OABANa, and PABA on sepiolite are pr oved to be excellent removers of aldehydes in ambient air. Among them, PABA . HCI is particularly good for ethanal.