Fatty acid phenyl esters

Wilsch, A. and Schneider, G.M. (1983) Determination of the capacity ratios of some fatty acid phenyl esters in supercritical carbon dioxide by supercritical fluid chromatography (SFC), Fresenius Z. Anal. Chem. 316, 265-267. 

Phenyl-polydimethyl siloxane OV-3, SE-52 350 Fatty acid methyl esters, alkaloids, drugs, halogenated compounds... 

Bistline and Stirton compared the CMC values of ester sulfonates with cyclic ester groups [54]. The phenyl esters have higher values than benzyl and cyclohexyl esters. The influence of the structure of the ester group decreases with increasing chain length of the hydrophobic fatty acid group. The cyclic esters of a-sulfostearic acid, for example, have nearly the same CMC values. 

Lippi et. al (87) and Dirstine (88) circumvented titration by converting the liberated fatty acids into copper salts, which after extraction in chloroform are reacted with diethyldithio-carbamate to form a colored complex which is measured photometrically. While the end point appears to be more sensitive than the pH end point determination, the advantages are outweighed by the additional steps of solvent extraction, centrifugation and incomplete extraction when low concentrations of copper salts are present. Other substrates used for the measurement of lipase activity have been tributyrin ( ), phenyl laurate (90), p-nit ro-pheny1-stearate and 3-naphthyl laurate (91). It has been shown that these substrates are hydrolyzed by esterases and thus lack specificity for lipase. Studies on patients with pancreatitis indicate olive oil emulsion is definitely superior to water soluble esters as substrates for measuring serum lipase activity. 

The i-poly(3HB) depolymerase of R. rubrum is the only i-poly(3HB) depolymerase that has been purified [174]. The enzyme consists of one polypeptide of 30-32 kDa and has a pH and temperature optimum of pH 9 and 55 °C, respectively. A specific activity of 4 mmol released 3-hydroxybutyrate/min x mg protein was determined (at 45 °C). The purified enzyme was inactive with denatured poly(3HB) and had no lipase-, protease-, or esterase activity with p-nitro-phenyl fatty acid esters (2-8 carbon atoms). Native poly(3HO) granules were not hydrolyzed by i-poly(3HB) depolymerase, indicating a high substrate specificity similar to extracellular poly(3HB) depolymerases. Recently, the DNA sequence of the i-poly(3HB) depolymerase of R. eutropha was published (AB07612). Surprisingly, the DNA-deduced amino acid sequence (47.3 kDa) did not contain a lipase box fingerprint. A more detailed investigation of the structure and function of bacterial i-poly(HA) depolymerases will be necessary in future. 

The Claisen condensation of diethyl oxalate with esters of fatty acids (cf. method 211) produces a-ethoxalyl esters which are thermally de-carbonylated to alkylmalonic esters. The over-all yields range from 78% to 91% for the conversion of fatry esters up to ethyl stearate. Phenyl-malonic ester is made in 85% yield. Powdered glass is sometimes used... 

Many lactose esters, including those of long-chain fatty acids, have been prepared by using the respective acid anhydride in either alkali or pyridine, and the respective acid chloride in pyridine. A mixture of lactose and phenyl isocyanate in pyridine gives an octaphenylurethan derivative of lactose. The yellow a and anomers of lactose octakis-[p-(p-nitrophenylazo)benzoate] were prepared for chromatographic studies. ... 

Pure essential oils are mixtures of more than 200 components, normally mixtures of terpenes or phenyl-propanic derivatives, in which the chemical and structural differences between compounds are minimal. They can be essentially classified into two groups A volatile fraction, constituting 90-95% of the oil in weight, containing the monoterpene and sesquiterpene hydrocarbons, as well as their oxygenated derivatives along with aliphatic aldehydes, alcohols, and esters and a nonvolatile residue that comprises 1-10% of the oil, containing hydrocarbons, fatty acids, sterols, carotenoids, waxes, and flavonoids. 

Figure 7. Methyl esters of unsaturated fatty acids as resolved on the 25%-cyanopropyl-25%-phenyl methyl siloxane DB-225. Split Injection to a 30m x 0.25mm column coated with a 0.25 m bonded film, hydrogen carrier at 46cm/sec, isothermal at 200 °C. Components 1, 14 1 methyl myristoleate 2, 16 1 trans methyl palmite-laidate 3, 16 1 cis methyl palmitoleate 4, 18 1 trans methyl elaidate 5, 18 1 cis methyl oleate 6, 18 2 trans methyl linolea-laidate 7, 18 2 cis methyl linoleate 8, 18 3 methyl linoleate ...

The synthesis of furan fatty esters containing a phenyl substituent at the 3- or 4-position of the furan ring was reported these involved methyl 9,10-epoxy-12-oxostearate as a key intermediate (85). The mono-, di-, and triacylglycerols of a Cj g furan fatty acid were prepared by chemical and enzymatic means (86). Furanoacety-lene phytoalexins (wyerone [19] and dihydro-wyerone [20]) were prepared in multigram quantities from furfural (87). The synthesis route of compound [19] is presented in Scheme 6. 

In addition to the substances described, several other compounds have been described as lipase inhibitors. Thus pancreatic lipase is inhibited by thiourea, chloroethanol, formaldehyde (351), by quinine and atoxyl (352), by chaulmoogric acid (353), by cinnamate and ricinoleate (354), by several fatty acids (355), by vitamin C (356), by chlortetracycline (357), by isoamyl alcohol, isoamyl isobutyrate, and other esters (358), and by several sulfa drugs, such as sulfadiazine or sulfathiazole (340, 359, 360). Pancreatic lipase is unaffected by diisopropyl fluorophosphate (DFP) but is inhibited by diethyl-p-nitro-phenyl phosphate (349, 361). Milk lipase, however, is stated to be inhibited by DFP (362). 

In the following section, structure of diglycerol fatty acid ester nonionic surfactant micelles in n-alkanes (straight-chain hydrocarbon oils from octane to hexadecane), and in two aromatic oils (phenyl octane and ethyl benzene) will be described. 

BENZYL, CYCLOHEXYL, AND PHENYL ESTERS OF ALPHA-SULFO FATTY ACIDS. 

Ethylene glycol n-butyl ether Ethylene glycol phenyl ether Formulated fatty acid ester Heptane Hexane... 

The equivalent chain-lengths (ECL) of the methyl ester derivatives of 79 unsaturated fatty acids have been determined by GC with fused silica columns coated with Carbowax 20M (polyethylene glycol), Silar 5CP, CP-Sil 84 (Chrompak/Vaiian) and a 5% phenyl-methyl silicone (Christie, 1988). CP-Sil 84 is equivalent to AT-SILAR-90, DB-23, Rtx-2330, SP-2330 [poly(80% biscyanopropyl)-20% cyanoptroylphenyl siloxane] (Grace, 2011). 

The phenyl esters of long chain fatty acids (Sections 7.8 and 7.9) are membrane-active microbicides they release phenolic compounds as the active ingredients. The advantage of these esters is that they are easier to handle and to apply than the phenolic compounds they are based on. 

Generally, microalgae lipids include nentral lipids, polar lipids, wax esters, sterols, and hydrocarbons, as well as phenyl derivatives (Naik et al, 2010). For biodiesel prodnction, natural lipids, which are nonpolar, are always targeted. Typically, most of the lipids produced from microalgae strains that have been tested for biodiesel prodnction have fatty acid constitutions similar to most common vegetable oils (Becker, 2004 Huang et al., 2012), as shown in Table 6.1. 

There are other examples of the calculation of phase equilibrium that are of practical interest and worthy of further discussion. For example, Rodrigues et al studied the phase equihbrium for (rice bran oil + fatty acid-s + ethanol + water + y-oryzanol + tocols). y-oryzanol is a mixture of several ferulic acid [(E)-3-(4-hydroxy-3-methoxy-phenyl)prop-2-enoic acid] esters of sterol and triterpene alcohols. Tocols consist of tocopherols and tocotrienols. y-oryzanol. Tocols are minor components of rice bran oil possessing antioxidant and other beneficial physiological properties. Rodrigues et al applied the pseudo-component method with the NRTL and the UNIQUAC model to calculate the LLE of this compositionally very complex system. For parameter estimation model fatty systems were investigated. 

Alcohols are usually esterified with fatty acids of similar structure. The characteristic structure is expressed by formula 3-42. The compound name is formed by the radical names of the alcohol and the bound acid. For example, ceryl cerotate is the ester of cerotic acid with ceryl alcohol. The main wax ester on the surface of sunflower seeds is ceryl cerotate. The main surface wax esters of apples and cabbage leaves are ceryl palmitate and ceryl stearate. The constituents of the epicuticular wax of apple fruits are also Cig-C26 fatty acid esters of (E)- and (Z)-p-coumaryl alcohol. The fatty acid esterification occurs at the y-hydroxyl group rather than at the 4-hydroxyl on the phenyl ring. 

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