Soap from fatty acids

Figure 4 Soap from fatty acid neutralization (C) (from Ref. 13).

In the production of soap from fatty acids the distillation process normally associated with fat splitting is usually a sufficient pretreatment for the raw materials (Von Barren and Klimmek, 1977). Methods are available, however, to treat the fatty acids prior to distillation to prevent undesirable by-product formation, e.g. acid washing to remove trace metals. It is good practice to store fatty acids for the manufacture of high-quality soaps for as short a time as possible to prevent deterioration. 

Neutralization Step The formation of soap from fatty acids is achieved through the reaction of the fatty acid with the appropriate caustic. This reaction is extremely rapid for... 

Nitrile Process. Fatty nitriles are readily prepared via batch, Hquid-phase, or continuous gas-phase processes from fatty acids and ammonia. Nitrile formation is carried out at an elevated temperature (usually >250° C) with catalyst. An ammonia soap which initially forms, readily dehydrates at temperatures above 150°C to form an amide. In the presence of catalyst, zinc (ZnO) for batch and bauxite for continuous processes, and temperatures >250° C, dehydration of the amide occurs to produce nitrile. Removal of water drives the reaction to completion. 

Salts of Organic Acids. Calcium salts of organic acids may be prepared by reaction of the carbonate hydroxide and the organic acid (9). Calcium lactate [814-80-2] is an iatermediate ia the purification of lactic acid from fermentation of molasses. Calcium soaps, soaps of fatty acids, ate soluble ia hydrocarbons, and are useful as waterproofing agents and constituents of greases (9). 

The solubihty characteristics of sodium acyl isethionates allow them to be used in synthetic detergent (syndet) bars. Complex blends of an isethionate and various soaps, free fatty acids, and small amounts of other surfactants reportedly are essentially nonirritant skin cleansers (66). As a rule, the more detersive surfactants, for example alkyl sulfates, a-olefin sulfonates, and alkylaryl sulfonates, are used in limited amounts in skin cleansers. Most skin cleansers are compounded to leave an emollient residue on the skin after rinsing with water. Free fatty acids, alkyl betaines, and some compatible cationic or quaternary compounds have been found to be especially useful. A mildly acidic environment on the skin helps control the growth of resident microbial species. Detergent-based skin cleansers can be formulated with abrasives to remove scaly or hard-to-remove materials from the skin. 

Long-chain fatty acids are insoluble in water, and their titration curves are concentration-dependent because of the formation of organized aggregates (acid soaps, soap micelles, fatty acid precipitates) which concentrate protons at the surface. At concentrations above the critical micellar concentration, solutions of long-chain fatty acid soaps manifest a diprotic curve when they are titrated from pH 10 to 4 (23). The first... 

If soap is to be produced from fatty acid rather than triglyceride, the oil is split , i.e. hydrolysed to give 3 moles of fatty acid plus glycerol and this can be achieved by treating the oil with steam at temperatures of ca 300°C. Fatty acids are often further distilled, to top and tail the carbon distribution, to focus on the 12-18 range. 

CLA has been synthesized from fatty acid and soap blends using SO2 in the presence of a substoichiometric amount of soap forming base (115). This reaction produced predominantly the aU tran -configuration of CLA. 

The major subgroups of anionic surfactants include the alkali carboxylates (soaps), sulfates, sulfonates, and to a smaller degree, phosphates. The esterification of alcohol with sulfuric acid yields probably the best-studied surfactant, sodium dodecylsulfate or SDS. SDS, a sulfate ester, is an extremely effective emulsifier because of its high-electrostatic repulsion. Other sulfates are, for example, sulfated esters from fatty acids, sulfated ethers, and sulfated fats and oils. Sulfonates stem from the reaction of sulfonic acid with suitable substrates. Members of the class of sulfonates are, for example, sulfonic acid salts or aliphatic sulfonates. Other anionic surfactants include substances such as carboxylated soaps and esters of phosphoric acid. 

Spent soap lyes, as they are drawn from the continuous saponification area or soap kettles, consist primarily of glycerine, sodium chloride, and water as well as small quantities of sodium hydroxide, sodium sulfate, sodium carbonate, soap, and fatty acids, and also some albuminous and oleaginous matter. To remove these impurities, the soap lye is generally treated in batches. 

Pseudo-hypocalcemia can occur in hemodialysis patients, particularly in those who have chylomicronemia before administration of heparin (120). This spurious hjrpocalce-mia is thought to result from lipolytic activity in vitro, sufficient to produce calcium soaps of fatty acid. This can be detected and eliminated by the analysis of blood samples immediately after venepuncture. During hemodialysis, there is a significant fall in plasma ionized calcium after intravenous administration of heparin (an average reduction of 0.03 mmol/1 after 10 000 lU) (121). 

Glycerin is mainly obtained from oils and fats as a by-product in the manufacture of soaps and fatty acids. It may also be obtained from natural sources by fermentation of, for example, sugar beet molasses in the presence of large quantities of sodium sulfite. Synthetically, glycerin may be prepared by the chlorination and saponification of propylene. 

Napalm, A coprecipitated aluminum soap from naphthenic acids and the fatty adds of coconut oil devdoped early in 1942 (Fieser. Harris, Hershberg, Morgana, Novdlo, Putnam) for prepn of gasoline gels for incendiary munitions U.S. pats. 2,606,107 (1952) Herron, U.S. pat. 2,684,339 (1954 to Safety Fuel Chem. Corp ). The name was derived from the naphthenic and palmitic acids which are its major constituents. Structure and mfg problems Chem. Historical account L. F. Fieser, The Scientific Method (Rdnhold, New York, 1964) Bruce, Chemical Warfare—Flame in Kirk-Othmer Encyclopedia of Chemical Technology (Interscience, New York, 1964) p 888. 

Esters. Organic esters of all kinds, including the esters of carbohydrates, are quite subject to hydrolysis with acids, bases, and, in many cases, enzymes. In this connection, the term saponification is commonly used instead of hydrolysis. The most important example is that of the saponification of fats and oils to make glycerol and either soap or fatty acids. The decomposition of ethyl and methyl acetates by water plus a catalyst has probably received more attention than any other case of hydrolysis by reason of its bearing on the general subject of catalysis. Hydrolysis of esters is reversible, unlike that of the carbohydrates, so that the equilibrium point may be approached from both sides. The following equations represent typical cases of ester hydrolysis ... 

Three of the F-T plants continued operation after the war. Schwarzheide in the Soviet Zone, which had a labor force of 3,600, produced gasoline for Soviet civilian and military consumption. Gewerkschaft Victor in Castrop-Rauxel and Krupp Treibstoffwerk in Wanne-Eickel in the British zone, as of February 1946 were producing oils and waxes from fatty acids and using them to make soaps and margarine [47]. The six other plants remained inoperative. Today none of the 21 synthetic fuel plants produces synthetic fuels. 

It is miscible with water and many organic solvents. Its molecule contains both a hydroxyl and an amine group, thus producing derivatives that have characteristics of both types of compounds. It is used as a softener and conditioning agent, and in the recovery and extraction of carbon dioxide and hydrogen sulfide from industrial gases. Its soaps with fatty acids are excellent emulsifiers for waxes. It is also utilized as an intermediote In the manufacture of rubber accelerators and dyestuffs. 

Farris [5] reported different qualities for both pathways the product yield from fatty acid is only -55% the main by-products are free DEA (22%) and amine soap and amino-amine (10% each). About 90% yield was reached in the pathway based on methyl ester the main by-products are free DEA (5%) and amide ester (4%). By using triglycerides directly, stiU 80% yield can be reached. 

Ethanolamine soaps produced from fatty acids are among the most industrially important emulsifiers. They are used in cosmetics, polishes, shoe aeams, car care products, drilling and cutting oils, and pharmaceutical ointments. Ethanolamine soaps combined with wax and resins are used as impregnating materials, protective coatings, and products for the care of textile and leather goods. 

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