Improved process for the preparation of Schiff base adducts of o-hydroxyaldehydes and amines, and composition of substances based thereon

摘要

An improved process is described for preparing Schiff base condensation adduct final products whose components comprise a protein having beneficial activity in animals, and an aromatic o-hydroxy aldehyde, which comprises bringing together the above-mentioned components in an aqueous environment at a pH of 7.0 or higher to form a reaction mixture, under conditions effective to drive said condensation reaction substantially to completion by removing from about 97.0% to about 99.9% by weight, preferably from about 98.0% to about 99.0% by weight of the water already present or produced during said condensation reaction, consistent with maintaining the integrity of the condensation reactants and adduct final product, and to assure a rate of conversion to said condensation adduct final product, i.e., with resulting yield of said condensation adduct final product of equal to or greater than about 98.5% by weight, preferably equal to or greater than about 99.5% by weight based on the weight of the reactants. Preferred aromatic o-hydroxy aldehydes comprise o-vanillin; salicylaldehyde; 2,3-dihydroxybenzaldehyde; 2,6-dihydroxybenz-aldehyde; 2-hydroxy-3-ethoxybenzaldehyde; or pyridoxal. A very wide range of proteins may be employed. The improved process provides yields over 90% and substantially quantitative conversion of the aldehyde and protein to the condensation adduct.