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ash' with water. The alkaline product from the wood ash was a crude solution of sodium and potassium carbonates called "lye". On boiling the vegetable oil with the lye, the soap (sodium and potassium salts of long-chained fatty acids) separated from the lye due to the dispersive interactions between the fatty acid alkane chains and were thus called "lyophobic". It follows that "lyophobic", from a physical chemical point of view, would be the same as "hydrophobic", and interactions between hydrophobic and lyophobic materials are dominantly dispersive. The other product of the soap-making industry was glycerol, which remained in the lye and was consequently termed "lyophilic". Thus, glycerol mixes with water because of its many hydroxyl groups and is very polar and hence is a "hydrophilic" or "lyophilic" substance. Hydrophobic and hydrophilic terms are extensively employed in biotechnology to

Hydrophobic and Hydrophilic Interactions The term "hydrophobic interaction" implies some form of molecular repulsion, which, of course, outside the Van der Waals radii of a molecule, is impossible. The term "hydrophobic force", literally meaning "fear of water" force, is an alternative to the well-established term, dispersive force. The term may have been provoked by the immiscibility of a dispersive solvent such as n-heptane with a very polar solvent

dispersive, polar and ionic groups in their total structure and thus the overall interactive character may be largely ionic, dispersive or polar depending on the distribution of the different interactive groups. It follows, that terms are required to describe the overall interactive property of a molecule as opposed to the interactive character of its specific groups. Virtually, by default, the most common terms that have been established to describe molecular interactive character are hydrophobic and hydrophilic. A hydrophobic substance is predominantly dispersive in character and  a hydrophilic substance is predominantly polar in character. Two other terms are less commonly used for the same purpose and they are lyophobic and lyophilic which are synonymous to hydrophobic and hydrophilic. The terms have a rather obscure origin and are not based on physical chemical considerations, but have evolved, somewhat arbitrarily, from the discipline of biology. Nevertheless, they are

The origin of the terms lyophobic (meaning fear of lye) and lyophilic (meaning love of lye) to describe interactive forces is very obscure and, in fact, is a product of the distant past. Essentially, these terms are alternatives for terms hydrophobic and hydrophilic, and, as such, might be considered somewhat irrelevant. These terms stemmed from the early days of the soap industry when soap was prepared by boiling a vegetable oil with an alkaline solution obtained from leaching wood ash with water. The alkaline product from the wood ash was a crude solution of sodium and potassium carbonates called lye. The result of boiling vegetable oil with the lye was the soap (sodium and potassium salts of long-chained fatty acids) which,

The term "hydrophobic interaction" unfortunately implies some form of molecular repulsion, which, outside the van der Waals radii of a molecule, is quite impossible. The word hydrophobic literally means "fear of water" and appears to have been provoked by the immiscibility of a dispersive solvent such as n-heptane with a very polar solvent such as water. However, n-heptane and water are immiscible, not because water molecules repel heptane molecules but because the forces between heptane

A number of examples of some specifically derivatized cyclodextrin stationary phases have been reported. In one example, the positions 2 and 6 are alkylated (pentylated) thus providing very dispersive (hydrophobic) centers that will interact strongly with any alkyl chains contained by the solutes. After the pentylation of the 2 and 6 positions, the hydroxyl group in the 3 position can then be trifluoroacetylated which produces a very different type of stationary phase. which has a wide field of application. It has been reported that the derivatized g-cyclodextrin is distinctly more selective than the b material. It has been employed in the separation of a very wide range of compound classes,