Formulation, Emulsion, and Thermal Stability of Emulsifiable Malathion Concentrate using Ethanol as a Solvent

摘要

This work considers the formulation, emulsion and thermal stability of malathion pesticide in the form of emulsifiable concentrate (E.C.). Ethanol as solvent and different types of emulsifiers is considered in the formulation using 50% emulsifiable malathion concentrate. Ethanol, which is polar solvent and miscible with water, is considered in this work instead of the nonpolar and immiscible aromatic solvents such as Dimethylbenzene. The target is to formulate emulsifiable environmentally safe pesticide using ethanol as a solvent. This solvent is selected because it is less harmful compared with aromatic solvents which often used. The emulsifiers are those that have a hydrophobic hydrophilic balance (HLB) value between eight and eighteen. Four samples conform to the criteria of the emulsion stability test for the formulation of 50% emulsifiable concentrate. These formulations contain the emulsifier concentration of 7, 8, 9, and 10-wt-%. Such samples also underwent a thermal stability tests. The degradation kinetics of the emulsifiable malathion concentrate follows a first order degradation rate. The shelf life of emulsifiable malathion concentrate was estimated using Arrhenius equation.