The properties of the selected solvent define, to a large extent, the type of the solvent-based separation technique. Consider the binary azeotropic mixture of ethanol-water and the solvents benzene or ethylene glycol. If benzene is used as the solvent, the resulting solvent-based separation process is called azeotropic distillation because ethanol-water-ben-zene forms a heterogeneous azeotropic system, as shown in Figure 2A. If, on the other hand, ethylene glycol is used as a solvent, the solvent-based

Figure 2 (A) Ternary VLLE diagram for ethanol-water-ben-zene (solvent). (B) Ternary homogeneous VLE diagram for ethanol-water-ethyleneglycol (solvent). Key: ..., heterogeneous liquid boiling surface; O, vapour line; A, critical point; □, azeo-tropes. All temperatures in °C.

separation technique is called extractive distillation because ethanol-water-ethylene glycol forms a homogeneous azeotropic system, as shown in Figure 2B.

Table 2 gives a list of different types of solvent properties that may be considered in the selection/design of a solvent. These properties are classified in terms of pure component, mixture and environmental. Table 3 expands on the nature of the environmental properties. While the pure component and environmental properties are usually available for a large number of chemical species, the mixture properties usually need to be estimated through suitable property prediction methods.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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