Inclusion of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) with β-cyclodextrin by different processing methods

Abstract

The interaction of the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) with β-Cyclodextrin produces the formation of a new inclusion compound in solution and in solid state. XRD, FTIR, DSC and SEM techniques have allowed to investigate the inclusion process of the three processing methods (co-precipitation, spray-drying and kneading) under test. Inclusion of 2,4-D in β-CD in solution was also studied by phase solubility, being determined for the complex an apparent stability constant of 336 M-1. At the solid state, co-precipitation and spray-drying were found to yield an inclusion complex in 1:1 stoichiometry. From these systems, it was attained an increase of 2,4-D aqueous dissolution rate as compared with the uncomplexed herbicide, the spray-dried outcomed being the most effective one. This finding would allow a more rational application of 2,4-D and thus diminish its risks as potential pollutant of ground waters and soils.