Acidolysis Reaction

A solution (or slurry) of the sample is refluxed for 4h. A sample/reagent ratio of 0.01 is recommended. The boiling point of the dioxane-water azeotrope (81.6% dioxane) is 87.8°C. Losses of solvent due to evaporation during the treatment should be avoided (Susarev and Guseva 1964, Froment and Robert 1970). (Note 1). 

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Pos twe-Tone Photoresists. The ester, carbonate, and ketal acidolysis reactions which form the basis of most positive tone CA resists are thought to proceed under specific acid catalysis (62). In this mechanism, illustrated in Figure 22 for the hydrolysis of tert-huty acetate (type A l) (63), the first step involves a rapid equihbrium where the proton is transferred between the photogenerated acid and the acid-labile protecting group ... 

Liquid crystal polyesters are made by a different route. Because they are phenoHc esters, they cannot be made by direct ester exchange between a diphenol and a lower dialkyl ester due to unfavorable reactivities. The usual method is the so-called reverse ester exchange or acidolysis reaction (96) where the phenoHc hydroxyl groups are acylated with a lower aHphatic acid anhydride, eg, acetic or propionic anhydride, and the acetate or propionate ester is heated with an aromatic dicarboxyHc acid, sometimes in the presence of a catalyst. The phenoHc polyester forms readily as the volatile lower acid distills from the reaction mixture. Many Hquid crystal polymers are derived formally from hydroxyacids (97,98) and thein acetates readily undergo self-condensation in the melt, stoichiometric balance being automatically obtained. 

As a by-product of the acidolysis reaction, the 0,/> -dihydroxystilbene (IX) was formed, obviously by the loss of a molecule of formaldehyde from the benzylium ion intermediate (IV) (broken line arrows), a reaction to be regarded as a reverse Prins reaction 29). 

It seems to the author, however, that other factors besides the ones considered by Bade and Huber must be involved. For example, in the cleavage of tetraalkyltins by mercuric chloride in methanol, bond energy differences are the same as in the acidolysis reaction and so are solvation differences because in both reactions the products are the compounds R3SnCl. Hence if only bond energy differences and R3SnCl solvation differences were important, the same reactivity sequences would be expected. But this is not observed at all as can be seen from the series of relative reactivity (Me4Sn = 100) in Table 13. The reactivity sequence for... 

Garcia, H.S., Storkson, J.M., Pariza, M.W., Hill Jr., C.G. 1998. Enrichment of butteroil with conjugated linoleic acid via enzymatic interesterification (acidolysis) reactions. Biotechnol. Lett. 20, 393-395. 

The fatty acid specificity in the acidolysis reaction has been examined (Table IV). 

Fig. 6.1.1. Monomeric phenols detected m lignin acidolysis reaction mixtures...

The tremendous thermodynamic driving force of six basic ammonia molecules combining with six protons results in an equilibrium constant for the reaction (Eq. 13.24) c( 10. Neverthdess. addihcation of a solution of hexaamminecobaltdll) results in no immediate change, and several days are required (at room temperature) fm d ra-dation of the comi x despite the favondde thomodynamics. The inertness of the Comdex results from the d)sence of a suitable low-energy pathway for the acidolysis reaction. 

Enzyme-catalyzed reactions are used to produce human mUkfat substitutes for use in infant formulas (46-48). Acidolysis reaction of a mixture of tripalmitin and unsaturated fatty acids using a i -l,3-specific lipase as a biocatalyst afforded TAGs derived entirely from vegetable oils rich in 2-position palmitate with unsaturated fatty acyl groups in the sn- and sn-3 positions (44). These TAGs closely mimic the fatty acid distribution found in human mUkfat, and, when used in infant formula instead of conventional fats, the presence of palmitate in the sn-2 position of the TAGs improved digestibility of the fat and absorption of other important nutrients such as calcium (46, 49). 

The fatty acid compositions of borage and evening primrose oils were also modified by incorporation of EPA using hpase PS-30 from Pseudomonas sp. as the biocatalyst (58). After acidolysis reaction, borage oil-based structured lipid contained 26.8% EPA and 15.2% GLA. Meanwhile, evening primrose oil-based structured lipid had EPA and GLA contents of 25.2% and 7.6%, respectively (58). 

This acid exchange parallels the alcoholysis reaction (Section 5.3) but in practice the latter is more important owing to the volatility of the glycol. In general the acidolysis reaction shown above does not contribute to the build-up of molecular weight. 

If A is derived from a weak acid HA, and HC is a strong hydrocarbon acid, the SnC bond can be formed by the acidolysis reaction ... 

Cyclopropanes can also be obtained in acidolysis reactions of cyclopropene-transition-metal complexes. This reaction has been used analytically to prove the eoordination of an intact three-membered ring to a metal eenter. For example, dichlorobis(> -cyclopentadienyl)niobium (10), upon treatment with sodium amalgam in toluene in the presence of eyclopropene, gives a moss-green eyclopropene eomplex 11 which can be isolated and characterized by its NMR spectrum. Treatment of complex 11 with hydrochloric acid results in the formation of almost pure cyclopropane, according to GC analysis. 

The employment of 1,3-selective lipases leads to structured TAG where specific acyl groups are confined to either the l-(3-) or 2-acylglycerol position. One of the earliest examples is cocoa butter substitute formed by 1,3-selective lipase-catalyzed acidolysis (reaction 1 of Fig. 3) of palm oil midfraction by palmitic acid (resulting in the replacement of 1-, 3-dipalmityl, 2-oleyl TAG by l-(3-) palmityl, 2-oleyl, 3- (1-) steryl TAG and 1-, 3-disteryl, 2-oleyl TAG, both of which are abundant in cocoa butter). The product... 

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