Humic-like acid derived from 1,2-naphthoquinone

A new fast and original method for producing synthetic humic acids by oxidation of 1,2-naphthoquinone by oxygen in an alkaline medium has been proposed. The elemental, structural-group composition and spectral characteristics of the obtained humic-like substances correspond to those of natural humic substances. The stoichiometry of the reaction was established by the volumetric method. The redox capacity of humic acids increased from 0.43 to 3.68 mmol∙g-1 with increasing solution from pH 5 to 11. Humic-like acids featured an ESR singlet signal with a width of 3.8 Gauss and g-factor close to the g-factor of the free electron (g = 2.0033).