Commercial fatty acid neutralization

Reaction with Fatty Acids and Esters. Alkanolamines and long-chain fatty acids react at room temperature to give neutral alkanolamine soaps, which are waxy, noncrystaUine materials with widespread commercial appHcations as emulsifiers. At elevated temperatures, 140 —160°C, A/-aIkanolamides are the main products, at a 1 1 reaction ratio (7,8). 

Saponification can proceed direcdy as a one-step reaction as shown above, or it can be achieved indirectly by a two-step reaction where the intermediate step generates fatty acids through simple hydrolysis of the fats and oils and the finishing step forms soap through the neutralization of the fatty acid with caustic soda. There are practical considerations which must be addressed when performing this reaction on a commercial scale. 

Commercially, soap is most commonly produced through either the direct saponification of fats and oils with caustic or the hydrolysis of fats and oils to fatty acids followed by stoichiometric (equal molar) neutralization with caustic. Both of these approaches yield workable soap in the form of concentrated soap solutions (- 70% soap). This concentration of soap is the target on account of the aqueous-phase properties of soap as well as practical limitations resulting from these properties. Hence, before discussing the commercial manufacturing of soap, it is imperative to understand the phase properties of soap. 

Ethoxylation of alkyl amine ethoxylates is an economical route to obtain the variety of properties required by numerous and sometimes smaH-volume industrial uses of cationic surfactants. Commercial amine ethoxylates shown in Tables 27 and 28 are derived from linear alkyl amines, ahphatic /-alkyl amines, and rosin (dehydroabietyl) amines. Despite the variety of chemical stmctures, the amine ethoxylates tend to have similar properties. In general, they are yellow or amber Hquids or yellowish low melting soHds. Specific gravity at room temperature ranges from 0.9 to 1.15, and they are soluble in acidic media. Higher ethoxylation promotes solubiUty in neutral and alkaline media. The lower ethoxylates form insoluble salts with fatty acids and other anionic surfactants. Salts of higher ethoxylates are soluble, however. Oil solubiUty decreases with increasing ethylene oxide content but many ethoxylates with a fairly even hydrophilic—hydrophobic balance show appreciable oil solubiUty and are used as solutes in the oil phase. 

A purified fatty acid is recommended for the preparation of a pure a-sulfo acid. Purified palmitic acid (m.p. 60.8-61.4°, neutralization equivalent 256.2) is prepared by twice recrystallizing a good commercial grade of palmitic acid from acetone at 0°, using a solvent ratio of 10 ml. to 1 g. However, the reaction may be applied to commercial saturated higher fatty acids, if the iodine number is sufficiently low. The checkers obtained similar results with recrystaUized Neo-Fat 1-56 (Armour and Company, Chicago, 111.) or Eastman white label palmitic acid. 

The phospholipids are biodegradable, but their presence m streams and water resources, especially in the form of soap stock, is undesirable. Fatly acid recovery from phospholipids is less than with neutral oils because of the lower fatty acid content. There are no known health hazards involved in the production of commercial lecithin from crude vegetable oils because the phospholipids are nonvolatile and are a nonirritaling food material. 

Improvement of membrane separation technology has resulted in the isolation of MFGM-enriched material from commercially available products. A phospholipid-rich fraction can be extracted from whey (Boyd et al., 1999) and buttermilk (Sachedva and Buchheim, 1997) with a reported yield of 0.25 g of phospholipids/g of protein in buttermilk (Sachdeva and Buchheim, 1997). Microfiltration of whey derived from the Cheddar cheese process, using 0.2 pm ceramic filters results in a fraction containing two major phospholipids, phosphatidylcholine and phosphatidylethanolamine, and lesser amounts of phosphatidylinositol, phosphatidylserine, sphingomyelin and cerebrosides (Boyd et al., 1999). The phospholipid fraction separated from the total lipids contains a larger proportion of mono- and polyunsaturated fatty acids (mainly oleic, Cig i and linoleic, C ) compared to the total lipid and the neutral lipid fraction (Boyd et al., 1999). 

The filtered oil can be treated with neutral or activated clays to remove color, peroxides, residual phosphatides, and soaps to produce oils with FFA fatty acids contents of less than 0.05 percent and 0 PV (peroxide value).110 The method has been patented and is being evaluated commercially. 

Diacylglycerols are produced in the fmit palm after harvest. The fruits are required to be processed within 24 hours after the harvest in order to control hydrolysis of the oil in the fruit by lipase. This guideline cannot be followed by all palm oil processors during the peak harvest season. As the trading rule for palm oil allows 5% free fatty acids in crude palm oil and 0.25% free fatty acid in neutralized palm olein (58), there is no incentive for the common palm oil processors in producing oils with lower free fatty acids. Commercially available palm oil and palm... 

Vegetable oil refinery lipid, feed grade (33.7), is obtained in the alkaline refining of a vegetable oil for edible use. It consists predominantly of the salts of fatty acids, glycerides, and phosphates. It may contain water and not more than 22% ash on a water-free basis. It is to be neutralized with acid before use in commercial feed. Includes IFN 4-05-078 (vegetable oil refinery lipid). 

According to Oomah et al. (1996), extraction of residual oil from commercially available flaxseed meal with hexane alone resulted in a higher oil recovery than methanol/hexane or methanol-ammonia-water/hexane. However, it should be noted that their starting material was meal and not seeds of flax. Analysis of the extracted lipids from the meal showed (Table 3) that hexane preferentially extracted the neutral lipids primarily composed of triacylglycerols (TAG). Neutral lipid fraction of oil extracted with methanol/hexane solvent system contained more monoacylglycerols (MAG), diacylglycerols (DAG) and free fatty acids (FFA) than the lipids extracted by other solvent systems (Table 3). Methanol/hexane solvent system extracted more polar lipids than methanol-water-am-monia/hexane system and this lipid fraction was composed mainly of phosphotidylcholine (PC). Polar lipids of methanol-ammonia-water/hexane extracted lipids contained also phosphotidylethanolamine (PE), lysophosphatidylcholine (LPC) and some unidentified compounds. 

Neutral lipids and fatty acids (Firms 11, 31, 60, 105, 133, 144), phospholipids and other complex compounds (Firms 11, 31,105,144) and standard mixtures for TLC and gas chromatography (Firms 11, 144) are commercially available. 

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