Higher fatty acids

Sodium Dispersions. Sodium is easily dispersed in inert hydrocarbons (qv), eg, white oil or kerosene, by agitation, or using a homogenizing device. Addition of oleic acid and other long-chain fatty acids, higher alcohols and esters, and some finely divided soHds, eg, carbon or bentonite, accelerate dispersion and produce finer (1—20 -lm) particles. Above 98°C the sodium is present as Hquid spheres. On cooling to lower temperatures, soHd spheres of sodium remain dispersed in the hydrocarbon and present an extended surface for reaction. Dispersions may contain as much as 50 wt % sodium. Sodium in this form is easily handled and reacts rapidly. For some purposes the presence of the inert hydrocarbon is a disadvantage. 

Okane et al. measured the CMC values of a-sulfonated fatty acid higher alcohol esters. These molecules can be regarded as double-chain amphiphiles, but the CMC values are about three to six orders of magnitude larger than expected for double-chain amphiphiles that can spontaneously form vesicles in water [60]. 

B. Non-volatile fatty oils (fats and fatty acids), higher alcohols, resins, and hydrocarbons... 

Materials produced from natural oils by oxidative polymerization reactions, e.g. binding agents in linoleum mats, will under the effects of moisture produce and emit degradation products such as fatty acids, higher aldehydes, and alcohols. 

Smith, Snyder and Harden (1995) have used negative ion ES/MS/MS to analyse the PLs of four Escherichia and Bacillus species. The principal bacterial PLs detected by this technique were PC and CL, accompanied by small amounts of PE. The negative ion spectrum for a chloroform/methanol extract of B. licheniformis showed three prominent peaks, at m/z 693, 707 and 721, accompanied by several minor peaks in the PL region of the mass spectra. The low-intensity peaks at m/z 647, 654, 661, 668 and 675 revealed that the M + 1 and M + 2 isotope peaks differed by half-unit mass increments rather than by unit mass increments, which indicates that these compounds were doubly charged. The peak at m/z 647 was of sufficient intensity to provide an informative product ion mass spectrum and had the correct molecular weight (1296) for a CL with four 15 0 fatty acids. Higher mass peaks in the series were CLs with replacement of one or more of the 15 0 fatty acids with longer chain fatty acids. The product ion mass spectrum... 

Temperature influences fermentation kinetics. The alcohol yield is generally lower at elevated temperatures, in which case some of the alcohol may be entrained with the intense release of carbon dioxide. Additionally, most of the secondary products of glyceropyruvic fermentation are found in greater concentrations. Fatty acids, higher alcohols and their esters are the most affected their formation is at its maximum at about 20°C and then progressively diminishes. Low fermentation... 

Crystallization accelerators have been described for PAs. As crystallization accelerators, there are low molecular weight PAs, higher fatty acids, higher fatty acid esters and higher aliphatic alcohols, which may be used independently or in combination. 

The lower members of the series are liquids soluble in water and volatile in steam. As the number of carbon atoms in the molecule increases, the m.p. and b.p. rise and the acids become less soluble in water and less volatile. The higher fatty acids are solids, insoluble in water and soluble in organic solvents. 

Some fairly typical results, obtained by LaMer and co-workers [275] are shown in Fig. IV-24. At the higher film pressures, the reduction in evaporation rate may be 60-90%—a very substantial effect. Similar results have been reported for the various fatty acids and their esters [276,277]. Films of biological materials may offer little resistance, as is the case for cholesterol [278] and dimyristoylphosphatidylcholine (except if present as a bilayer) [279]. 

If, on the other hand, RCOOH is a higher fatty acid and R OH a polyhydric alcohol, then the enzyme is called a lipase. Stearin or glyceryl tristearate (a fat) is... 

With higher aliphatic acids, RCOOH, keten yields first a mixed anhydride CH3COOCOR, which can be distilled under reduced pressure by slow distillation at atmospheric pressure the mixed anhydride undergoes rearrangement into the anhydride of the higher fatty acid and acetic acid, for example ... 

The higher alcohols occur in minor quantities primarily as the wax ester (ester of a fatty alcohol and a fatty acid) in many oilseed and marine sources. Free alcohols octacosanol [557-61-9] C2gH gO, and triacontanol [28351-05-5] have been isolated in very small amounts from sugarcane and its... 

Eats and oils from a number of animal and vegetable sources are the feedstocks for the manufacture of natural higher alcohols. These materials consist of triglycerides glycerol esterified with three moles of a fatty acid. The alcohol is manufactured by reduction of the fatty acid functional group. A small amount of natural alcohol is also obtained commercially by saponification of natural wax esters of the higher alcohols, such as wool grease. 

Hydrogenolysis Process. Patty alcohols are produced by hydrogenolysis of methyl esters or fatty acids ia the presence of a heterogeneous catalyst at 20,700—31,000 kPa (3000—4500 psi) and 250—300°C ia conversions of 90—98%. A higher conversion can be achieved using more rigorous reaction conditions, but it is accompanied by a significant amount of hydrocarbon production. 

A USDA report indicates that between 1967 and 1988, butter consumption remained stable at 2 kg per capita, margarine dropped from 5.1 to 4.7 kg, and measured total fat intake per day dropped from 84.6 to 73.3 g (14). This study also projects that the reduced consumption of tropical oils is only temporary and will return to former use levels, possibly even higher. One reason for this projected rise in tropical oil consumption is the knowledge of the beneficial effects of medium-chain length acids high in lauric oils. There is a keen interest in omega-3 fatty acids, as well as linoleic acid, contained in fish oils. 

Fatty acids are susceptible to oxidative attack and cleavage of the fatty acid chain. As oxidation proceeds, the shorter-chain fatty acids break off and produce progressively higher levels of malodorous material. This condition is known as rancidity. Another source of rancidity in fatty foods is the enzymatic hydrolysis of the fatty acid from the glycerol. The effect of this reaction on nutritional aspects of foods is poorly understood andhttie research has been done in the area. 

Recently, the use of Hpase enzymes to iateresterify oils has been described (23). In principle, if a 1,3-speciftc Hpase is used, the fatty acid ia the 2 position should remain unchanged and the randomization occur at the terminal positions. However, higher temperatures, needed to melt soHd fats, may cause a 1,2-acyl shift and fatty acids are scrambled over all positions. 

Measurement of Unsaturation. The presence of double bonds in a fatty acid side chain can be detected chemically or through use of instmmentation. Iodine value (IV) (74) is a measure of extent of the reaction of iodine with double bonds the higher the IV, the more unsaturated the oil. IV may also be calculated from fatty acid composition. The cis—trans configuration of double bonds may be deterrnined by infrared (59) or nmr spectroscopy. Naturally occurring oils have methylene-intermpted double bonds that do not absorb in the uv however, conjugated dienes maybe deterrnined in an appropriate solvent at 233 nm. 

Concrete. Hydrocarbon extracts of plant tissue, concretes are usually soHd to semisoHd waxy masses often containing higher fatty acids such as lauric, myristic, palmitic, and stearic as well as many of the nonvolatiles present in absolutes. 

On heating, an alkanolamine soap first dehydrates to the amide this is also obtained from the methyl ester of the fatty acid by heating with the alkanolamine at 60°C in the presence of a catalytic amount of sodium methoxide. Methanol is removed under partial vacuum. At higher temperature, the amide is dehydrated to an oxa2oline. 

---