New Solvents for Agrochemical Formulations—A Green Chemistry Approach

Solvents play a key role in the delivery of pesticides to their respective targets. One of the most common types of agrochemical formulation is emulsifiable concentrate (EC), which basically comprises an active ingredient (AI), a solvent or blend of solvents, surfactants, and small amounts of additives. The most common solvents present in these formulas contribute to volatile organic compound (VOC) emissions, are flammable, classified as hazardous air pollutant (HAP) substances, i.e., are toxic to users and farmers, and can be phytotoxic to crops. The use of solvents that are more benign to human health and the environment is part of the “green chemistry” movement. The Principles of Green Chemistry were considered during selection and design of the new solvents described in this paper. Important features defined for these new molecules were low volatility, being derived from renewable feedstock, and low toxicity and phytotoxicity. From these studies, we present new ester solvents based on citric acid and branched alcohols derived from sugar cane. They had many desirable physical and chemical properties herein described as high boiling point, low volatility, and low freezing point. Due to their chemical characteristics, it is believed that they have low toxicity to humans and to the environment. A remarkable benefit of these products is that they do not cause eye irritation. The lab tests results showed that solubility of selected active ingredients in these esters exceed their commercial concentrations without crystallization. Based on these findings, stable EC formulations were developed using surfactants with sustainable characteristics.