Long chain aliphatic esters

Raghavan and coworkers have reported on the preparation of 4-hydroxybenzoic add esters (parabans) possessing antimicrobial activity by esterification of 4-hydroxybenzoic acid (Scheme 6.153) [299]. Optimum results were obtained using the alcohol (1-butanol) as solvent in the presence of catalytic amounts of zinc(II) chloride or p-toluenesulfonic acid (pTsOH) under atmospheric conditions. After 5 min of microwave irradiation at 120 °C, ca. 40% conversion to the ester was observed. Related studies on the synthesis of long-chain aliphatic esters have been described by Mariani and coworkers [300]. 

Dextran phosphates with additional long chain aliphatic ester functions such as palmitoyldextran phosphates exhibit antitumour activity (Fig. 10). 

Long chain aliphatic esters, commonly called waxes, are components of epicuticular waxes of the olive fruits (Bianchi and Vlahov, 1994). Whilst in virgin olive oils the wax concentration is negligible, in olive-residue oil the wax content is considerable. Thus, the presence of long chain esters in olive oil is evidence of the presence of solvent extracted olive oil, also commonly called sansa olive oil. The detection and quantification of waxes in olive oil is an official method. As shown in Table 2.2, virgin olive oils fit for consumption must contain less than 250 mg/kg of waxes the limits are 350 mg/kg for categories 4,5 and 6, whilst for olive-residue oil the amount is expected to be over 350 mg/kg. 

In 1958, Wynder et al. (4355) described the effect of varying the pyrolysis temperature on the yield of pyrolysate from an n-hexane extract from tobacco. The extracted material constituted 5.4% of the original tobacco weight and consisted of long-chained saturated and unsaturated aliphatic hydrocarbons, glycerides and other esters, solanesol and phytosterols and their esters, long-chained aliphatic esters, and a-tocopherol. Major findings from their study included (see also Table XXV-2) ... 

The acylation of cellulose with acid chlorides in DMA/LiCl is most suitable for the homogeneous synthesis of readily soluble partially functionalized long-chain aliphatic esters and substituted acetic acid esters (Table 16.3). In contrast to the anhydrides, the fatty acid chlorides are soluble in the reaction mixture and soluble polysaccharide esters may be formed with a very high efficiency. Even in the case of stearoyl chloride, 79 per cent of the reagent is consumed for the esterification of cellulose. 

Moldovan, Z., lover, E., Bayona, J. M. (2002). Systematic characterisation of long-chain aliphatic esters of wool wax by gas chromatography-electron impact ionisation mass spectrometry. Journal of Chromatography A, 952(1-2), 193-204. 

For rigid PVC the extract will be much smaller, typically 1-5%, and will consist of lubricants such as long-chain aliphatic esters, e.g. glyceryl mono-ricinoleate, long-chain aliphatic acids and alcohols, and hydrocarbon and amide waxes. Metal-based stabilisers such as metal carboxylates or organo-tin compounds may be present. Also present may be nonmetal stabilisers such as ESBO, organic phosphites, bisphenol A, and polyols such as trimethylolpro-pane or pentaerythritol. 

All long chain aliphatic esters have a band near 725 cm ( 13.79pm) which may, in some samples, appear as doublet. Typical compounds are ethyl palmitate and glyceryl di-stearate. Both of these substances exhibit a band near 3340 cm ( 2.99pm) due to the presence of hydroxyl groups. The observation of this band is useful in that esters derived from poly-functional alcohols generally exhibit this absorption. 

The net conclusion is an unsaturated long chain aliphatic ester, which is characteristic of a vegetable or animal oil. 

LONG CHAIN ALIPHATIC ESTER - POSSIBLY UNSATURATED... 

LONG CHAIN ALIPHATIC ESTER - POSSIBLY UNSATURATED 4905 CARBONYL COMPOUND - CLASS 5 (CONSULT MANUAL)... 

Esters of aliphatic dibasic carboxylic acids Long-chain methyl esters of carboxylic acids... 

To the first category belong the homo- and copolymerization of macromonomers. For this purpose, macromolecules with only one polymerizable end group are needed. Such macromonomers are made, for example, by anionic polymerization where the reactive chain end is modified with a reactive vinyl monomer. Also methacrylic acid esters of long-chain aliphatic alcohols or monofunctional polyethylene oxides or polytetrahydrofurane belong to the class of macromonomers. 

There are several plasticizers for PVC that may be used in propellants. Weil (19) mentions sebacates, phthalates, adipates, and glycol esters of higher fatty acids as being desirable. Dibutyl sebacate, dioctyl sebacate, and 2-ethylhexyl adipate are all good. The plasticizer has a most important effect on the physical properties of the cured propellant and the variation of these properties with temperature. Long chain, aliphatic plasticizers impart improved low temperature flexibility, and hence are preferable to aromatic plasticizers such as the phthalates. An increase in plasticizer viscosity leads to an increase in viscosity of the mixed pro-... 

The procedure described is substantially that of Toussaint and MacDowell, with minor modifications. Vinyl esters of long-chain aliphatic acids have also been prepared by the reaction of acetylene with the appropriate acids, - but this reaction is not so convenient for small-scale laboratory preparationsr... 

The compound represented by an electron-impact spectrum and a chemical-ionization (methane) spectrum is an ester of a long-chain, aliphatic alcohol. Interpret the spectra and identify the compound. 

Solvent Dyes (see also Section 3.10). The 1 2 chromium and cobalt complex dyes devoid of any hydrophilic substituent have a considerable solubility in organic solvents, especially alcohols, ketones, and esters. Enhanced solubility can be achieved by converting the metal-complex sodium salts into salts of organic cations [57], Such cations may be cationic dyes, long-chain aliphatic ammonium ions, or protonated guanidines. For example, the bluish red solvent dye 34 reaches a solubility in organic solvents of up to 1000 g/L [58],... 

The main components of this layer are generally long-chain aliphatic hydrocarbons and fatty acids, as well as smaller amounts of methyl esters, long-chain aliphatic alcohols and aldehydes, glycerides, and cholesterol. Similar compounds are present on the web and spider cuticle. It has been established that these compounds may be responsible for the antifungal and antibacterial properties of silk and also play a role in communication. 

Determination of Quantitative and qualitative Wax esters (long chain aliphatic... 

All six of the chlorophenyl-substituted carboxylic acids are derived from acid chlorides of long-chain aliphatic half esters. To prepare these uncommon intermediates in sufficient amounts, practicable preparative methods had to be developed. Methods are given for converting appropriate ,co-dicarboxylic acids to the corresponding acid chloride half esters. 

Long-chain esters of pentaerythiitol have been prepared by a variety of methods. The tetranonanoate is made by treatment of methyl nonanoate [7289-51-2] and pentaerythiitol at elevated temperatures using sodium phenoxide alone, or titanium tetrapropoxide in xylene (12). Phenolic esters having good antioxidant activity have been synthesized by reaction of phenols or long-chain aliphatic acids and pentaerythiitol or tdmethylolpropane (13). 

The direct esterification of undec-lO-enoic acid with phenylalkanols using DCC and 4-(N,N-dimethylamino)pyridine affords the corresponding esters in quantitative yields. Esterification of the secondary alcohol 655 with long chain aliphatic acids in the presence of DCC and DMAP affords the dioxane esters 656 in yields of 80-93 %. ... 

Additional information concerning the length of alkyl bridges and substituents is obtained from GC/MS data. The long-chained acid esters identified show aliphatic substituents from C7-C17 and aliphatic bridges of and C 5 lengths. The long-chained acid... 

The waxes include a variety of esters of long chain aliphatic acids with long chain aliphatic alcohols, more frequently containing C12 to C34 carbon atoms. Some other simple compounds are included in this group of lipids [laj. 

The term lipids in this entry is restricted to esters and amides of the long-chain aliphatic monocarboxylic acids, the fatty acids, and to their biosynthetically or functionally related compounds. The most abundant lipids are the esters of fatty acids with glycerol (1,2,3-trihydroxypropane), denoted as glycerolipids. Lipids are classified according to the number of hydrolytic products per mole. Simple (or neutral) lipids release two types of products (e.g., fatty acids and glycerol). 

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