Fatty acids and alcohols

The major components of camauba wax are aHphatic and aromatic esters of long-chain alcohols and acids, with smaller amounts of free fatty acids and alcohols, and resins. Camauba wax is very hard, with a penetration of 2 dmm at 25°C and only 3 dmm at 43.3°C. Camauba also has one of the higher melting points for the natural waxes at 84°C, with a viscosity of 3960 rare]/s at 98.9°C, an acid number of 8, and a saponification number of 80. 

Subsequent to the adsorption onto a surface, surfactants, especially long chain fatty acids and alcohols tend to undergo alterations such as two-dimensional associations in the adsorbed layer, presumably at rates kinetically independent of preliminary steps. These intra-layer reactions have been shown to be very slow. 

Vegetable oils or triglycerides obtained from the seeds of various plants are the source of a wide variety of fatty acid esters and derivatives (fatty acids and alcohols) with different molecular structure (chain length, number and position of... 

Apart from being used as bio-diesel , fatty acid esters, which are obtained from fatty acids and alcohols, are becoming increasingly interesting as biodegradable replacements for mineral oils. In some application areas such as chain-saw oil, gearbox oils, hydraulic oils and lubricants for crude oil production these oleochemical products have already proved themselves. 

Robb, I.D. Determination of the aqueous solubility of fatty acids and alcohols, Aust. J. Chem., 18 2281-2285, 1966. 

It has been shown (Friberg, 2003 Birdi, 2002, 2008) that there exists a correlation between foam stability and the elasticity [E] of the film (i.e., the monolayer). In order for E to be large, surface excess must be large. Maximum foam stability has been reported in systems with fatty acid and alcohol concentrations well below the minimum in y. Similar conclusions have been observed with -C12H25S04Na [SDS] + -C12H25OH systems that give minimum in y versus concentration with maximum foam at the minimum point (Chattoraj and Birdi, 1984). Because of mixed mono-layer formation it has been found that SDS + C12H25OH (and some other additives) make liquid-crystalline structures at the surface. This leads to a stable foam (and liq-... 

Suberin is a composite of polymeric phenylpropanoids and ester-linked long chain fatty acids and alcohols and consists of a hydrophobic layer attached to the cell walls of roots, bark and the vascular system (8,10). The phenylpropanoid portion of suberin purportedly has a lignin-like structure to which both aliphatic domains and hydroxycinnamic acids are esterified. 

These conditions are realisable experimentally with solutions of the higher fatty acids and alcohols with water. The cr, curve falls rapidly at first and subsequently approaches almost asymptotically a limiting value. With the aid of the Gibbs equation we may readily determine the form of the T, W curve, where T is the surface The surface concentration may be assumed equal to V if we... 

Esters are common components in cosmetics and skin-care products. They can be synthesized from fatty acids and alcohols using either chemical or enzymatic reactions. The chemical reactions are normally catalysed by acid catalysts. Enzymatic synthesis is carried out under milder conditions and therefore it provides products of very high purity. A range of esters such as isopropyl palmitate and isopropyl myristate are now produced industrially using enzymatic synthesis. The reactions are carried out in solvent-free systems using an immobilised lipase as catalyst. In order to get high yields in the reactions, water is removed continuously. 

Ester synthesis of fatty acid ethyl ester. The lipase-catalyzed esterification of fatty acid and alcohol is well-known. It was also favorable for the esterification of poly unsaturated fatty acids under mild conditions with the enzyme. However, the activity of native lipase is lower in polar organic solvents, i.e. ethanol and methanol. The synthesis of Ae fatty acid ethyl ester was carried out in ethanol using the palmitic acid-modified lipase. As shown in Figure 7, the reactivity of the modified lipase in this system was much higher than that of the unmoditied lipase. 

The phytochemicals that are discussed below may be divided Into three classical categories alkaloids, flavonolds, and terpenes. Straight chain carbon confounds, such as hydrocarbons, waxes, fatty acid and alcohols also occur In glands. The alkaloids tend to react as feeding deterents and as poisons (43). They are probably the major class found In any lists of plant toxins (44, 45). Flavonolds are well known antibacterial. 

In the following a survey is given of the substances which have been found to alter intercellular coupling. First drugs will be considered which uncouple gap junctions. A number of lipophilic compounds have been described to reduce gap junctional coupling. These substances include alcohols like hep-tanol and octanol, saturated and unsaturated fatty acids, and alcohols and... 

Lipids are esters of long-chain fatty acids and alcohols or of closely related derivatives. The chief difference between these substances is the type of alcohol in fixed oils and fats, glycerol combines with the fatty acids in waxes, the alcohol has a higher molecular weight, e.g., cetyl alcohols. 

Mair, B. J., "Terpenoids, Fatty Acids and Alcohols as Source Materials... 

Parker, P. L., Fatty Acids and Alcohols, in Organic Geochemistry, ... 

A wide variety of long-chain fatty acids increase transdermal delivery the most popular is oleic acid. It is relevant that many penetration enhancers contain saturated or unsaturated hydrocarbon chains and some structure-activity relationships have been drawn from the extensive studies of Aungst et al. [22,23] who employed a range of fatty acids and alcohols, sulfoxides, surfactants, and amides as enhancers for naloxone. From these experiments, it appears that saturated alkyl chain lengths of around Cio to C12 attached to a polar head... 

Many insoluble substances, such as long-chain fatty acids and alcohols, can (with the aid of suitable solvents) be spread on to a water surface, and if space permits will form a surface film one... 

As remarked previously, the physical state of a monolayer depends on the lateral cohesive forces between the constituent molecules. By a suitable choice of chain length and temperature, straight-chain fatty acids and alcohols, etc., can be made to exhibit the various monolayer states, one CH2 group being equivalent to a temperature change of c. 5-8 K. 

The clearest results were obtained with the normal, saturated fatty acids and alcohols. These formed stable films, which would stand considerable compression laterally, and (at room temperature on distilled water) gave a very clearly marked critical area at which the surface pressure first appeared, this point being of course Pockels s critical point of the first diminution of surface tension. As the area was reduced from large initial areas no surface pressure could be detected until the area had reached about 22 sq. A. per molecule and at 20 5 sq. A. the pressure increased very rapidly indeed with further increase of pressure. The curve I of Fig. 15 shows the relation between surface pressure and area per molecule, which is obtained with accurate apparatus for the fatty acids on water curve III is that obtained with the alcohols.3... 

Careful work by Nutting and Harkins1 shows, confirming some indications in earlier work of the author s, that condensed films of fatty acids and alcohols, with close-packed heads, occupy slightly smaller areas as the chain length is considerably increased. When the chains are closely packed, the area also appears a little smaller with the longer chains, but the data are not so complete. 

The fatty acids and alcohols were purchased research grade materials. Their melting points are shown in Table I. 

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