Conductimetric method for the determination of phenolic groups in phlobaphene and tannin from Pinus Radiata D. Don: solvent effect

Abstract

Conductimetric titration of phenolic groups in phlobaphene, tannin and model compounds in water-organic solvents were investigated. The solvents used were water, water-methanol (3 + 2) and water-dimethyl sulphoxide (1 + 1). The most satisfactory results were obtained in the last mixture. The values obtained were as follows: 1.07 OH groups in catechol, 1.62 OH, groups in resorcinol and 3.64 OH groups in catechin. For phlobaphene (M_n 6500) and tannin (M_n 2600) the phenolic contents found were 53.5 and 23.0 per mole, respectively.