Lipophilicity, fat-liking, refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Hexane is an Alkane Hydrocarbon with the Chemical formula CH3(CH24CH3 or C6H14 Toluene, also known as methylbenzene or phenylmethane, is a clear water -insoluble liquid with the typical smell of Paint thinners redolent of ^[1] These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true. Thus lipophilic substances tend to dissolve in other lipophilic substances, while hydrophilic (water-loving) substances tend to dissolve in water and other hydrophilic substances. Hydrophile, from the Greek (hydros "water" and φιλια (philia "friendship" refers to a physical property of a Molecule

Lipophilicity, hydrophobicity and non-polarity (the latter as used to describe intermolecular interactions and not the separation of charge in dipoles) all essentially describe the same molecular attribute; the terms are often used interchangeably. However, the terms "lipophilic" and "hydrophobic" are not synonymous, as can be seen with silicones, which are hydrophobic but not lipophilic. In Chemistry, hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of Silicones are largely inert compounds with a wide variety of forms and uses

Contents 1 Chemical bonding 2 Surfactants 3 See also 4 References

Chemical bonding

Lipophilic substances interact within themselves and with other substances through van der Waals forces. The Van der Waals equation is an Equation of state that can be derived from a special form of the potential between a pair of molecules (hard-sphere repulsion They have little to no capacity to form hydrogen bonds. A hydrogen bond results from a Dipole-dipole force between an Electronegative atom and a Hydrogen atom bonded to Nitrogen, Oxygen When a molecule of a lipophilic substance is enveloped by water, surrounding water molecules enter into an 'ice-like' structure over the greater part of its molecular surface, the thermodynamically unfavourable event that drives oily substances out of water. In Physics, thermodynamics (from the Greek θερμη therme meaning " Heat " and δυναμις dynamis meaning " Being 'driven out of water' is the quality of a substance referred to as hydrophobic (water-avoiding or water-fearing). Thus lipophilic substances tend to be water insoluble. They invariably have large o/w (oil/water) partition coefficients. In the fields of organic and Medicinal chemistry, a partition (P or distribution coefficient (D is

Surfactants

Surfactants are compounds that are amphiphilic (or amphipathic), having a hydrophilic, water interactive 'end', referred to as their 'head group', and a lipophilic 'end', usually a long chain hydrocarbon fragment, referred to as their 'tail'. Surfactants are wetting agents that lower the Surface tension of a liquid allowing easier spreading and lower the Interfacial tension between two liquids Amphiphile (from the Greek αμφις amphis both and φιλíα Philia: love friendship is a term describing a Chemical compound possessing both They congregate at low energy surfaces, including the air-water interface (lowering surface tension) and the surfaces of the water-immiscible droplets found in o/w emulsions (lowering interfacial tension). For the work of fiction see Surface Tension (short story. Surface tension is a property of the surface of a Liquid that causes it to An emulsion ( IPA: /ɪˈmʌlʃən/ is a mixture of two Immiscible (unblendable liquids At these surfaces they naturally orient themselves with their head groups in water and their tails either sticking up and largely out of water (as at the air-water interface) or dissolved in the water-immiscible phase that the water is in contact with (e. g. as the emulsified oil droplet). In both these configurations the head groups strongly interact with water while the tails avoid all contact with water. Surfactant molecules also aggregate in water as micelles with their head groups sticking out and their tails bunched together. A micelle (rarely micella, plural micelles) is an aggregate of Surfactant molecules dispersed in a liquid Colloid. Micelles draw oily substances into their hydrophobic cores, explaining the basic action of soaps and detergents used for personal cleanliness and for laundering clothes. A micelle (rarely micella, plural micelles) is an aggregate of Surfactant molecules dispersed in a liquid Colloid. Micelles are also biologically important for the transport of fatty substances in the small intestine surface in the first step that leads to the absorption of the components of fats (largely fatty acids and 2-monoglycerides).

Cell membranes are bilayer structures principally formed from phospholipids, molecules which have a highly water interactive, ionic phosphate head groups attached to two long alkyl tails. Phospholipids are a class of Lipids and are a major component of all Biological membranes All phospholipids contain a Diglyceride, a Phosphate A phosphate, an Inorganic chemical, is a salt of Phosphoric acid.

See also

• Lipophobicity
• Lipophilic bacteria

References

1. ^ Compendium of Chemical Terminology, lipophilic, accessed 15 Jan 2007. Lipophobicity, also sometimes called lipophobia is a Chemical property of Chemical compounds which literally means " Fat rejection" Lipophilic bacteria ( Fat -liking bacteria) are Bacteria that may proliferate in Lipids. Compendium of Chemical Terminology (ISBN 0-86542-684-8 is a book published by IUPAC containing internationally accepted definitions for terms in Chemistry.

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