Reactive extraction of protocatechuic acid by di-n-octylamine and optimisation with Box–Behnken design

Abstract

ABSTRACT Protocatechuic acid (PCA) is typically produced by microbial fermentation. Its separation from fermentation broth or aqueous waste streams is of great importance. This study aimed to recover PCA by a secondary amine namely di-n-octylamine (DOA). Three organic solvents, namely isobutyl methyl ketone, propyl acetate and linalool, were used with DOA. Important extraction parameters were optimised by response surface methodology. DOA/isobutyl methyl ketone system showed 95.84% extraction efficiency under the optimum conditions. The maximum E% of the DOA/propyl acetate system was 86.73%. The maximum E% of the DOA/linalool system was 81.71%. Additionally, a thermodynamic study was carried out, and the reactions were endothermic. Highlights Protocatechuic extraction by di-n-octylamine has been done first in the literature. Different kinds of solvents have been used to solve di-n-octylamine. Useful information is obtained for the design of protocatechuic acid reactive extraction.