Oleic acid ester hydrolysis

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) ... 

Sulfated Natural Oils and Fats. Sulfated natural triglycerides were the first nonsoap commercial surfactants introduced in the middle of the nineteenth century. Since then sulfates of many vegetable, animal, and fish oils have been investigated (see also Fats AND FATTY oils). With its hydroxyl group and a double bond, ricinoleic acid (12-hydroxy-9,10-octadecenoic acid) is an oil constituent particularly suited for sulfation. Its sulfate is known as turkey-red oil. Oleic acid is also suited for sulfation. Esters of these acids can be sulfated with a minimum of hydrolysis of the glyceride group. Polyunsaturated acids, with several double bonds, lead to dark-colored sulfation products. The reaction with sulfuric acid proceeds through either the hydroxyl or the double bond. The sulfuric acid half ester thus formed is neutralized with caustic soda ... 

Acidic Hydrolysis. Hydrolysis of esters by use of water and a mineral acid leads to an equiUbrium mixture of ester, alcohol, and free carboxyHc acid. Complete reaction can only be achieved by removal of alcohol or acid from the equiUbrium. Because esters have poor solubiUty in water, the reaction rate in dilute acids is fairly low. Therefore, emulsifiers such as sulfonated oleic acid or sulfonated aromatic compounds (TwitcheU reagent) are added to facihtate the reaction. 

There are a few reported cases of esterases that catalyze not only hydrolysis but also the reverse reaction of ester formation, in analogy with the global reaction described for serine peptidases (Fig. 3.4). Thus, cholesterol esterase can catalyze the esterification of oleic acid with cholesterol and, more importantly in our context, that of fatty acids with haloethanols [54], Esterification and transesterification reactions are also mediated by carboxyleste-rases, as discussed in greater detail in Sect. 7.4. 

Palmitic acid is present as cetyl ester in spermaceti from which, by hydrolysis, the acid may be obtained it is present in bee s wax as the mehssic ester and in most vegetable and animal oils and fats, in greater or lesser amounts, as glyceryl tripalmitate or as mixed esters, along with stearic and oleic adds, Palmitic acid is separated from stearic and oleic acids by fractional vacuum distillation and by fractional crystallization. With NaOH, palmitic add forms sodium palmitate, a soap, Most soaps are mixtures of sodium stearate, palmitate, and oleate. 

Answer Mild hydrolysis cleaves the ester linkages between glycerol and fatty acids, forming (a) glycerol and the sodium salts of palmitic and stearic acids (b) D-glycerol 3-phosphocholine and the sodium salts of palmitic and oleic acids. 

Pelargonic acid has been prepared by the oxidation of oleic acid and by hydrolysis of octyl cyanide or heptylacetoacetic ester. ... 

Table V. Relative Maximal Rates V of Hydrolysis of Oleic Acid Esters by Pancreatic Lipase, Compared with Triolein, V = 1.0 (7)...

In addition to the hydrolysis of cocaine, the purified human liver cocaine methyl ester hydrolase also catalyzed the ethyl transesterification of cocaine with ethanol to form cocaethylene and methanol as shown in figure 1 (Dean et al. 1991 Brzezinski et al. 1994). Both the hydrolytic and the ethyl transesterification reactions increased as the two activities were analyzed in protein fractions obtained during the enzyme purifi-cation by column chromatography. This suggests that the separate activities are catalyzed by the same enzyme. The Km values for cocaine and ethanol of the purified enzyme at pH 7.3 were 116 M and 43 mM, respectively. The carboxylesterase also catalyzes the formation of ethyloleate from oleic acid and ethanol (Tsujita and Okuda 1992 Brzezinski et al. 1994). Other hydrolases or ester transferases have been reported to catalyze similar substrate "ethylation" reactions. 

A membrane cell recycle reactor with continuous ethanol extraction by dibutyl phthalate increased the productivity fourfold with increased conversion of glucose from 45 to 91%.249 The ethanol was then removed from the dibutyl phthalate with water. It would be better to do this second step with a membrane. In another process, microencapsulated yeast converted glucose to ethanol, which was removed by an oleic acid phase containing a lipase that formed ethyl oleate.250 This could be used as biodiesel fuel. Continuous ultrafiltration has been used to separate the propionic acid produced from glycerol by a Propionibacterium.251 Whey proteins have been hydrolyzed enzymatically and continuously in an ultrafiltration reactor, with improved yields, productivity, and elimination of peptide coproducts.252 Continuous hydrolysis of a starch slurry has been carried out with a-amylase immobilized in a hollow fiber reactor.253 Oils have been hydrolyzed by a lipase immobilized on an aromatic polyamide ultrafiltration membrane with continuous separation of one product through the membrane to shift the equilibrium toward the desired products.254 Such a process could supplant the current energy-intensive industrial one that takes 3-24 h at 150-260X. Lipases have also been used to prepare esters. A lipase-surfactant complex in hexane was used to prepare a wax ester found in whale oil, by the esterification of 1 hexadecanol with palmitic acid in a membrane reactor.255 After 1 h, the yield was 96%. The current industrial process runs at 250°C for up to 20 h. 

Since 1970, a new class of cyano compounds has been isolated from certain seed oils that are of interest as some members, like cyanogenic glycosides, liberate HCN on enzymic or mild chemical hydrolysis All the authenticated compounds occur in several genera of the Sapindaceae (soapberry) family " and they can comprise up to 50% v/v of the extract, e.g. in kusum seed oil. These cyanolipids are mono- or di-esters of mono- or dihydroxy-nitriles and 4 types are known (Figure 22). The chain length of the fatty acid moiety, which may be saturated or not (e.g. commonly from oleic acid), can be C14 to C22 with C18 and C20 predominant and the double bond in type 3 can be Z or E, but structural variations are few. After hydrolysis the a-hydroxynitriles derived from types 1 and 4 are cyanogenic. In many plant species one type occurs to the virtual exclusion of the others thus type 1 accumulates in Allophyllus and Paullina spp, whereas type 2 is characteristic of... 

They found that the fatty acids in the 1 or 3 position, that is, the primary alcohol ester groups, were readily split, and that oleic acid in the 1 position was hydrolyzed at a slightly faster rate than palmitic acid in the 1 position. However, the more rapid splitting of oleic acid was regarded as a rather special case, and they concluded that as a general rule the existence of one or two double bonds in the fatty acid did not affect the rate of hydrolysis. 

Orlistat (tetrahydrolipstatin) is a reversible inhibitor of oral, gastric, and pancreatic lipases. This inhibitor forms an ester linkage with serine (serine-152) in the active site of the lipase so that a decrease in the rate of lipid hydrolysis will occur [37]. Orlistat decreases the oral taste sensitivity to both oleic acid and triolein in obese subjects [38]. These results further suggest a role for lingual lipase in oral fat hydrolysis and detection. However, a conclusive role for human lingual lipase in oral fatty acid hydrolysis and detection still remains imclear at the present time [39]. 

At the molecular level, saponification corresponds to base-promoted hydrolysis of the ester groups in triglycerides (Section 14.3C). The resulting soaps contain mainly the sodium salts of palmitic, stearic, and oleic acids from tallow and the sodium salts of lauric and myristic... 

Cholesterol accumulated in atheromatous lesions is largely ester-ifled with fatty acids, especially oleic acid. The change in fatty acid composition of cholesterol esters between circulating lipoproteins and atheromas indicates an esterification process operative in the developing lesion. Kotharl et al have demonstrated enzymes in normal artery which catalyze both synthesis and hydrolysis of cholesterol esters. Reaction rates of esterification and hydrolysis were found to be strongly dependent on the physical state of the reactants an emulsified state promoted esterification, whereas a micellar state promoted hydrolysis. 

This lipase showed a high specificity for long-chain unsaturated fatty acid. The best hydrolysis rate was obtained with the oleic acid ester and the presence of double bonds enhances lipase activity. 

The oleic acid methyl ester derived from high oleic - sunflower oil could be an ideal starting material for this reaction. The resulting di-acids can be used to make polymers (- polymers from fats and oils). Another interesting reaction is the m. of ethylene with ->oleic or - erucic aeid methyl ester to yield an olefin and a medium-chain fatty acid (after - hydrolysis of the methyl ester). 

Unsaturated fatty acids or methyl esters are obtained via hydrolysis with water or by transesterification with methanol, while glycerol is produced as a by-product. The structures of some common unsaturated Cig-fatty acids, such as oleic, linoleic, and linolenic are shown in Scheme 1. 

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