In its neutral form, juglone, a compound from the naphthoquinone family, is found naturally in walnut hulls, leaves, and roots. Although juglone’s allelopathic properties can be exploited and the compound can be used for weed management, the neutral form of juglone presents negative environmental effects such as: toxicity to aquatic species, runoff and drift, worker exposure. These disadvantages can be addressed through the conversion of the neutral juglone into an anionic form by pairing it with surfactant cations (phosphonium cations, quaternary ammonium cations) to overcome undesirable features of the parent compound. In our research group, the main focus is to synthesize new juglone salts that will change juglone’s mobility and therefore will decrease its environmental impact. To be able to test the synthesized compounds as potential herbicides and infer impact on the environment, the mobility and water solubility in soils of different pHs (acidic, neutral, and basic) needs to be determined.  <br/>We previously showed that, at neutral pH (6.99), juglone in anionic form has a higher water solubility than neutral juglone. Here we will present our solubility study along with the absorption spectra of the two forms of juglone (neutral, juglone free acid, and anionic, tetrabutylphosphonium salt of juglone, [PBu4][Jug]) in aqueous solution of pH = 9 at room temperature.

Absorption spectra of juglone in its anionic and neutral form in aqueous solutions of basic pH

2019 Spring National Meeting

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