Saturated acids

Multiply unsaturated linolenic and linoleic acid residues make triglycerides more vulnerable to oxidative degradation than oleic acid which is relatively stable. It is therefore desirable to hydrogenate the most unsaturated residues selectively without production of large quantities of stearic (fully saturated) acid. The stepwise reduction of an unsaturated oil may be visualized as ... 

Sohd fats may show drastically different melting behavior. Animal fats such as tallow have fatty acids distributed almost randomly over all positions on the glycerol chain. These fats melt over a fairly broad temperature range. Conversely, cocoa has unsaturated fatty acids predominantly in the 2 position and saturated acids in the 1 and 3 positions. Cocoa butter is a brittle sohd at ambient temperature but melts rapidly just below body temperature. 

Table 7. Saturated Acids as % of Total Acids of Milk Fat ...

These oxazolines have cationic surface-active properties and are emulsifying agents of the water-in-oil type. They ate acid acceptors and, in some cases, corrosion inhibitors (see Corrosion). Reaction to oxazoline also is useful as a tool for determination of double-bond location in fatty acids (2), or for use as a protective group in synthesis (3). The oxazolines from AEPD and TRIS AMINO contain hydroxyl groups that can be esterified easily, giving waxes (qv) with saturated acids and drying oils (qv) with unsaturated acids. 

Branched-Chain Saturated Acids" under "Eatty Acids (Branched-Chain)" in ECT 1st ed., VoL 6, pp. 259—262, by M. D. Reiner (in part), and J. A. Eield (in part). Union Carbide and Carbon Corp. "Branched-Chain Acids" under "Eatty Acids" in ECT 2nd ed., VoL 8, pp. 849—850, by W. C. Ault, U.S. Department of Agriculture "Branched-Chain Acids" under "Carboxylic Acids" in ECT 3rd ed., Vol. 4, pp. 861—863, by R. W. Johnson, Jr., Union Camp Corp. 

Perfluoro(methylcyclohexane) [355-02-2] M 350.1, b 76.3", d 1.7878. Refluxed for 24h with saturated acid KMn04 (to oxidise and remove hydrocarbons), then neutralised, steam distd, dried with P2O5 and passed slowly through a column of dry silica gel. [Glew and Reeves J Phys Chem 60 615 1956.] Also purified by percolation through a Im neutral activated alumina column, and H-impurities checked by NMR. 

The prime function of the saturated acid is to space out the double bonds and thus reduce the density of cross-linking. Phthalic anhydride is most commonly used for this purpose because it provides an inflexible link and maintains the rigidity in the cured resin. It has been used in increasing proportions during the past decade since its low price enables cheaper resins to be made. The most detrimental effect of this is to reduce the heat resistance of the laminates but this is frequently unimportant. It is usually produced by catalytic oxidation of o-xylene but sometimes naphthalene and is a crystalline solid melting at 131°C. 

Many mechanical properties are dependent on the density of cross-links and on the rigidity of the molecules between cross-links. It has already been shown that cross-link intensity may be controlled by varying the ratio of unsaturated to saturated acids whereas rigidity is to a large extent determined by the structure of the saturated acid employed. 

Diallyl phthalate (see also Section 25.3) has also been used as a laminating resin but because of its higher price it has been largely replaced by the glycol-saturated acid-unsaturated aeid polyesters. 

The preparation of long-chain fatty acids has been carried out in this way because cleavage of 115 with strong sodium hydroxide gives the ketoacid (116), which is easily reduced by the Wolf-Kishner method to the saturated acid. A similar sequence of reactions can be carried out starting with the cyclopentanone enamine, and this method allows lengthening the chain... 

Abstufung,/. gradation graduation, abstumpfen, v.t. neutralize, saturate (acids) truncate blunt, dull, deaden, -abgestumpft, p.a. neutralized, etc. blunt, dull. Abstumpfung, /. neutralization, etc. (see ab-stumpfen). 

Hydrogenation of 3-pyridinecarboxylic acids is apt to be accompanied by extensive decarboxylation (2S), but this unwanted reaction can be prevented by carrying out the reaction in the presence of one equivalent of base (33,79). Ruthenium (33), rhodium (29), platinum oxide (2S,59), and palladium (30) have all proved effective catalysts for reduction of pyridinecarboxylic acids to the saturated acid. 

For the preparation of the prepolymer, a mixture corresponding typically to mole ratios of diol unsaturated acid saturated acid of 3.3 2 1 is polymerised by stirring the ingredients together at elevated temperatures, normally 150-200 °C. The slight excess of diol is to allow for possible evaporation... 

The most frequently used systematic nomenclature names the fatty acid after the hydrocarbon with the same number and arrangement of carbon atoms, with -oic being substituted for the final -e (Genevan system). Thus, saturated acids end in -anoic, eg, octanoic acid, and unsaturated acids with double bonds end in -enoic, eg, octadecenoic acid (oleic acid). 

The fatty acid composition of the Baker cypress is comparatively complex. The major saturated acids were identified as palmitic (16 0) [chain lengthmumber of double bonds], stearic (18 0), and arachidic (20 0) with only minor contributions from... 

The specific behaviour of unsaturated fatty acids under oxidation is determined by the position and the number of double bonds in the fatty acid molecule. The stepwise oxidation of an unsaturated acid to the position of a double bond in it proceeds in a manner similar to that of saturated acid oxidation. If the double bond retains the same configuration (trans-configuration) and position (A2,3) as those of the enoyl-CoA, which is produced during the oxidation of saturated fatty acids, the subsequent oxidation proceeds via conventional route. Otherwise, the oxidation reaction proceeds with the involvement of an accessory enzyme, A3,4-CiS-A2,3jrans-enoyl-CoA isomerase this facilitates the translocation of the double bond to an appropriate position and alters the double-bond configuration from cis to trans. 

The unsaturated fatty acid oxidation proceeds at a rate higher over that for saturated acids. For example, if the oxidation rate for saturated stearic acid is taken as a reference value, the oxidation rate for oleic acid is i 1 times, linolic acid, 114 times, linolenic acid, 170 times, and arachidonic acid, nearly 200 times as high as that for stearic acid. 

Erudc acid is a constituent of various natural oils but is most conveniently obtained from rape seed oil. The process described above is essentially that of Reimer and Will.1 Methods have been developed for obtaining pure erudc add free from saturated acids,2 but these involve time-consuming procedures of fractional precipitation and crystallization, and necessarily give poor yields. The product obtained above is satisfactory for most purposes. 

Ethyl-2-methyl-2-octenoic acid has been prepared only by this method. An alternate synthesis of a-alkyl-a,fl-unsaturated adds proceeds via a-bromination of the saturated acid, followed by dehy-drohalogenation with quinoline at elevated temperatures.11 The present method is especially well adapted to preparation of a/y-dialkyl-a,j3-unsaturated acids. 

Saturated triglyceride -made using saturated acid Unsaturated triglyceride -made using unsaturated acid... 

Cholanic acid C24H40O2, a monobasic saturated acid containing four hydroaromatic rings, is the parent substance of the two natural acids, which are its trihydroxy- and dihydroxy-derivatives. It is very highly probable that the following structural formula for cholic acid is correct ... 

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