Fatty acids stearic

Laurie, myristic, palmitic, and stearic fatty acids make up most of the saturated fatty acids found in fats. Oleic acid, linoleic acid, and linolenic acid are the most abundant unsaturated fatty acids found in oils. 

Typically, an unhardened cottonseed oil is composed of 2.5% stearic fatty acid and 22-23% palmitic fatty acid, which are the principal saturated fatty acids. The unsaturated fatty acids are composed of approximate 18% oleic, 54% linoleic, and less than 1 % each of linolenic and pahnitoleic fatty acids. If the hardening reaction was completely selective, before any hydrogen was absorbed by oleic fatty acid the linoleic fatty acid would have to be completely converted to oleic. On the disappearance of the linoleic fatty acid, the oleic would next absorb hydrogen to be converted to the fully saturated stearic fatty acid. This degree of selectivity is never attained in practice but how closely it is approximated depends on the catalyst type and dosage, temperature, and pressure. 

Each common fat or oil has a definite crystal habit that is determined by four factors (1) palmitic fatty acid content, (2) distribution and position of palmitic and stearic fatty acids on the triglyceride molecule, (3) degree of hydrogenation, and (4) the degree of randomization. Table 10 identifies the crystal habit of hydrogenated edible oils (27). 

Stearic fatty acid is saturated, oleic contains one olefin group at the carbn (9) position, linoleic fatty acid contains two olefin groups at the carbons (9 and 12) positions. Linolenic fatty acid contains three olefin groups at the carbons (9, 12 and 15) positions. Eleosteric acid contains olefin groups at carbons (9, 11 and 13) and the double bonds are conjugated. In addition, a mixture of isomers exists within the structure of these materials. Also, erythro- and threo-conformations are present in these same structures, but of undetermined proportions. 

Chem. Desaip. Diacetylated tartaric add esters of glycerol (oleic/stearic) fatty acid esters... 

Chem. Descrip. Sorbitan stearic fatty acid ester Ionic Nature Nonionic CAS 1338-41-6 EINECS/ELINCS 215-664-9 Uses Emulsifier for production of milk replacers Lactomul SMS-20 [Cognis]... 

Chem. Descrip. Polyglycol (20) sorbitan stearic fatty acid ester CAS 9005-67-8... 

SNG Substitute natural gas. soaps Sodium and potassium salts of fatty acids, particularly stearic, palmitic and oleic acids. Animal and vegetable oils and fats, from which soaps are prepared, consist essentially of the glyceryl esters of these acids. In soap manufacture the oil or fat is heated with dilute NaOH (less frequently KOH) solution in large vats. When hydrolysis is complete the soap is salted out , or precipitated from solution by addition of NaCl. The soap is then treated, as required, with perfumes, etc. and made into tablets. 

The term fat is applied to solid esters of fatty acids with glycerol (glycerides) if the fat is liquid at the ordinary temperature, it is conventionally called a fatty oil, vegetable oil or animal oil. The acids which occur most abundantly are palmitic ticid CH3(CHj),4COOH, stearic acid CH3(CH2)isCOOH and oleic acid CH3(CH2),CH=CH(CH2),C00H. Upon hydrolysis, fats yield glycerol and the alkali salts of these acids (soaps) ... 

Separation of Fatty Acids. Tall oil is a by-product of the pulp and paper manufacturiag process and contains a spectmm of fatty acids, such as palmitic, stearic, oleic, and linoleic acids, and rosia acids, such as abietic acid. The conventional refining process to recover these fatty acids iavolves iatensive distillation under vacuum. This process does not yield high purity fatty acids, and moreover, a significant degradation of fatty acids occurs because of the high process temperatures. These fatty and rosia acids can be separated usiag a UOP Sorbex process (93—99) (Tables 8 and 9). 

The saturated fatty acids, stearic [57-11-4] and palmitic [57-10-3], are found in animal fats and dairy products. Extensive studies point to the deleterious effect of these acids on arterial walls as a result it is recommended that saturated fatty acid intake be carefully controlled and intake limited (23). 

Hydrogena.tlon. Lecithin can be hydrogenated. The resulting lecithins have only saturated fatty acid residues (palmitic or stearic acid) and are more or less colorless and crystalline. 

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. 

Bisamides. Methylenebisamides are prepared by the reaction of the primary fatty amide and formaldehyde in the presence of an acid catalyst. AijAT-Methylenebisoleamide has been made via this route without the use of refluxing solvent (55). Polymethylenebisamides can be made from fatty acid, esters, or acid haUdes with diamines while producing water, alcohol, or mineral acid by-products. Eatty acids and diamines, typically ethylenediamine, have been condensed in the presence of NaBH and NaH2P02 to yield bisamides (56). When stearic acid, ethylenediamine, and methyl acetate react for 6 h at... 

Many primary fatty amides which are available from various manufacturers are Hsted in Table 3. In 1986 approximately 55,000 metric tons of amides and bisamides were produced world wide (58), the majority of which are bisamides, followed in volume by primary amides. Most of these products are shipped in sohd form in bag or dmm quantities. Major producers of primary fatty amides are Akzo, Glyco, Humko, and Sherex. Bisamides are produced by Akzo, Milacron, and Syntex. There are over 100 producers of alkanolamides in the world, most of which are small specialized manufacturers to a specific industry. GAP, Henkel, Sherex, and Witco are among the principal producers. The most widely used alkanolamides are the Ai,Ai-bis(2-hydroxyethyl) fatty amides, mostly produced from middle-cut coco fatty acids (6% capryflc, 7% capric, 51% lauric, 19% myristic, 9% palmitic, and 2% stearic acids). An estimated 77,000 metric tons of alkanolamide was produced worldwide in 1986 (59). 

Activators. Activators are chemicals that increase the rate of vulcanization by reacting first with the accelerators to form mbber soluble complexes. These complexes then react with the sulfur to achieve vulcanization. The most common activators are combinations of zinc oxide and stearic acid. Other metal oxides have been used for specific purposes, ie, lead, cadmium, etc, and other fatty acids used include lauric, oleic, and propionic acids. Soluble zinc salts of fatty acid such as zinc 2-ethyIhexanoate are also used, and these mbber-soluble activators are effective in natural mbber to produce low set, low creep compounds used in load-bearing appHcations. Weak amines and amino alcohols have also been used as activators in combination with the metal oxides. 

A study of the effect of stearic acid and 2iac oxide on a sulfonamide-accelerated, sulfiir-cured natural mbber compound dramatically showed the need for both 2iac and fatty acid activators (Fig. 7) (21). 

Preparation of Emulsions. An emulsion is a system ia which one Hquid is coUoidaHy dispersed ia another (see Emulsions). The general method for preparing an oil-ia-water emulsion is to combine the oil with a compatible fatty acid, such as an oleic, stearic, or rosia acid, and separately mix a proportionate quantity of an alkah, such as potassium hydroxide, with the water. The alkah solution should then be rapidly stirred to develop as much shear as possible while the oil phase is added. Use of a homogenizer to force the resulting emulsion through a fine orifice under pressure further reduces its oil particle size. Liquid oleic acid is a convenient fatty acid to use ia emulsions, as it is readily miscible with most oils. 

Four columns are needed to produce the desired products. Considering the Sharp Distillation Sequencing heuristics, heuristic (/) does not apply, as there is more than one product in this mixture. Fatty acids are moderately corrosive, but none is particularly more so than the others, so heuristic (2) does not apply. The most volatile product, the caproic and capryflc mixture, is a small (10 mol %) fraction of the feed, so heuristic (3) does not apply. The least volatile product, the oleic—stearic acids, is 27% of the feed, but is not nearly as large as the capric—lauric acid product, so heuristic (4) does not apply. The spht between lauric and myristic acids is closest to equimolar (55 45) and is easy. Therefore, by heuristic (5) it should be performed first. The boiling point list implies that the distillate of the first column contains caproic, capryflc, capric, and lauric acids. This stream requires only one further separation, which by heuristic (/) is between the caproic—capryflc acids and capric—lauric acids. 

Considering their heat sensitivity, the separation of fatty acids and rosin with minimal degradation by fractional distillation under vacuum and/or in the presence of steam is surprisingly good (3). Tad od rosin (TOR) contains about 2% fatty acid and smad amounts of neutrals. Tad od fatty acid (TOFA) contains as Htde as 1.2% rosin and 1.7% neutrals. In typical U.S. TOFA, 49% of the fatty acids is oleic, 45% linoleic, and 3% palmitic, stearic, and eicosatrienoic acid. TOR and TOFA are upgraded to resins and chemicals for the manufacture of inks (qv), adhesives (qv), coatings (qv), and lubricants (see Lubrication AND lubricants). 

A series of sorbitol-based nonionic surfactants are used ia foods as water-ia-oil emulsifiers and defoamers. They are produced by reaction of fatty acids with sorbitol. During reaction, cycHc dehydration as well as esterification (primary hydroxyl group) occurs so that the hydrophilic portion is not only sorbitol but also its mono- and dianhydride. The product known as sorbitan monostearate [1338-41 -6] for example, is a mixture of partial stearic and palmitic acid esters (sorbitan monopalmitate [26266-57-9]) of sorbitol, 1,5-anhydro-D-glucitol [154-58-8] 1,4-sorbitan [27299-12-3] and isosorbide [652-67-5]. Sorbitan esters, such as the foregoing and also sorbitan monolaurate [1338-39-2] and sorbitan monooleate [1338-43-8], can be further modified by reaction with ethylene oxide to produce ethoxylated sorbitan esters, also nonionic detergents FDA approved for food use. 

The solubihty of water in fatty acids, 0.92% for stearic acid at 68.7°C, is greater than the solubiHty of the acid in water, 0.0003% for stearic acid at 20°C, and this solubihty tends to increase with increasing temperature (21). SolubiHties of aHphatic acids in organic solvents demonstrate another example of the alternating effect of odd vs even numbered acids (Table 8). 

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