When the critical frequency assumes a small value, the interaction of the parameter is known as tangent loss. This parameter defines the ability of a material (in most cases, a solvent) to convert microwave energy into thermal energy. According to the loss tangent values, solvents or materials can, in principle, be classified as strong (tan δ > 0.5), moderate (tan δ ≈ 0.1-0.5), and weak (tan δ < 0.1) absorbents . For practical purposes, achieving efficient microwave heating (2.45 GHz) requires the presence of a solvent or material classified as a strong absorber (tan δ > 0.5) .