Aliphatic esters ethyl acetate

The initial study of the La3 +-catalyzed methanolysis of carboxylate esters163 reported the apparent second-order rate constant for La2 + ( OCH3)2-catalyzed methanolysis of some representative examples of aryl esters (2, 5 and 2,4-dinitrophenyl acetate (14)), phenyl benzoate (15) and three aliphatic esters, ethyl acetate, isopropyl acetate (16) and tert-butyl acetate (17). Given in Table 6 are the rate constants for the La3+ and methoxide-catalyzed methanolysis of these esters along with... 

Aliphatic Esters Methyl acetate Ethyl acetate... 

Cellulose nitrate Esters (ethyl acetate. Aliphatic hydrocarbons... 

Aliphatic esters and ketone 50 % by volume ethane acid ethyl ester (ethyl acetate) 50 % by volume 4-methyl-pentanol-(2) (methyl isobutyl ketone)... 

The formation of acyloins (a-hydroxyketones of the general formula RCH(OH)COR, where R is an aliphatic residue) proceeds best by reaction between finely-divided sodium (2 atoms) and esters of aliphatic acids (1 mol) in anhydrous ether or in anhydrous benzene with exclusion of oxygen salts of enediols are produced, which are converted by hydrolysis into acyloins. The yield of acetoin from ethyl acetate is low (ca. 23 per cent, in ether) owing to the accompanying acetoacetic ester condensation the latter reaction is favoured when the ester is used as the solvent. Ethyl propionate and ethyl ji-butyrate give yields of 52 per cent, of propionoin and 72 per cent, of butyroin respectively in ether. 

The Claisen condensation of an aliphatic ester and a thiazolic ester gives after acidic hydrolysis a thiazolylketone (56). For example, the Claisen condensation of ethyl 4-methyl-5-thiazolecarboxylate with ethyl acetate followed by acid hydrolysis gives methyl 4-methyl-5-thiazolyl ketone in 16% yield. 

There have been numerous studies on the kinetics of decomposition of A IRK. AIBMe and other dialkyldiazenes.46 Solvent effects on are small by conventional standards but, nonetheless, significant. Data for AIBMe is presented in Table 3.3. The data come from a variety of sources and can be seen to increase in the series where the solvent is aliphatic < ester (including MMA) < aromatic (including styrene) < alcohol. There is a factor of two difference between kA in methanol and k< in ethyl acetate. The value of kA for AIBN is also reported to be higher in aromatic than in hydrocarbon solvents and to increase with the dielectric constant of the medium.31 79 80 Tlic kA of AIBMe and AIBN show no direct correlation with solvent viscosity (see also 3.3.1.1.3), which is consistent with the reaction being irreversible (Le. no cage return). 

The silica gel surface is extremely polar and, as a result, must often be deactivated with a polar solvent such as ethyl acetate, propanol or even methanol. The bulk solvent is usually an n-alkane such as n-heptane and the moderators (the name given to the deactivating agents) are usually added at concentrations ranging from 0.5 to 5% v/v. Silica gel is very effective for separating polarizable materials such as the aromatic hydrocarbons, nitro hydrocarbons (aliphatic and aromatic), aliphatic ethers, aromatic esters, etc. When separating polarizable substances as opposed to substances with permanent dipoles, mixtures of an aliphatic hydrocarbon with a chlorinated hydrocarbon such as chlorobutane or methylene dichloride are often used as the mobile... 

The above example serves to illustrate the basis of the procedure employed for the characterisation of aliphatic esters, viz., hydrolysis to, and identification of, the parent acids and alcohols. Most esters are liquids a notable exception is dimethyl oxalate, m.p. 54°. Many have pleasant, often fruit-like, odours. Many dry esters react with sodium, but less readily than do alcohols hydrogen is evolved particularly on warming, and a solid sodio derivative may separate on cooling (e.., ethyl acetate yields ethyl sodioacetoacetate ethyl adipate gives ethyl sodio cj/cZopentanone carboxylate). 

An attractive alternative is to study intramolecular reactions. These are generally faster than the corresponding intermolecular processes, and are frequently so much faster that it is possible to observe those types of reaction involved in enzyme catalysis. Thus groups like carboxyl and imidazole are involved at the active sites of many enzymes hydrolysing aliphatic esters and amides. Bimolecular reactions in water between acetic acid or imidazole and substrates such as ethyl acetate and simple amides are frequently too slow to... 

Although the present procedure illustrates the formation of the diazoacetic ester without isolation of the intermediate ester of glyoxylic acid />-toluenesulfonylhydrazone, the two geometric isomers of this hydrazone can be isolated if only one molar equivalent of triethylamine is used in the reaction of the acid chloride with the alcohol. The extremely mild conditions required for the further conversion of these hydrazones to the diazo esters should be noted. Other methods for decomposing arylsulfonyl-hydrazones to form diazocarbonyl compounds have included aqueous sodium hydroxide, sodium hydride in dimethoxyethane at 60°, and aluminum oxide in methylene chloride or ethyl acetate." Although the latter method competes in mildness and convenience with the procedure described here, it was found not to be applicable to the preparation of aliphatic diazoesters such as ethyl 2-diazopropionate. Hence the conditions used in the present procedure may offer a useful complement to the last-mentioned method when the appropriate arylsulfonylhydrazone is available. 

Unavailable because experimental methods for estimation of this parameter for aliphatic esters are lacking in the documented literature. Based on its solubility values, adsorption of ethyl acetate is not expected to be significant. 

In total, 4,777 solutes and 10,198 IgD values were analyzed. From these data, the correlation matrix of size 49 X 49 (48 conventional solvents + IL) was derived. It appeared that the solvents most close to [C4CiIm][PFJ (i.e., having the highest pairwise correlation coefficient solvent/IL) are esters with a short alkyl chain (ethyl acetate correlation coefficient r = 0.95, as determined by the distribution ratios for n = 11 solutes butyl acetate r = 0.92, n = 30) and substituted aromatic hydrocarbons (m-xylene r = 0.92, n = 20). The most distant from ILs are aliphatic hydrocarbons. Interestingly, the correlation with 1-octanol is moderate, r = 0.76, n = 56. 

In flavor compositions, aliphatic esters are preferred for artificial fruit aromas as in nature, acetates and ethyl esters prevail. 

Esters of primary aliphatic alcohols show an initial increase in rate with increasing acid concentration, but the curve, illustrated in Fig. 1 for ethyl acetate, passes through a maximum at an intermediate acid concentration (50-60% H2S04), and the rate coefficient subsequently falls almost to zero in the region of 80% acid. Finally, the rate increases slightly between 80% and 100% H2S04. Methyl acetate is rather more reactive than the ethyl ester in above about 50% H2S04, but /i-propyl acetate shows closely similar reactivity, so that the curve for ethyl acetate can be considered to represent the typical behaviour of a primary alkyl ester. 

Oxyanions of sufficient basicity will catalyze the hydrolysis of all but the least reactive esters but since the latter include the esters of the common aliphatic alcohols, early attempts to detect the reaction were negative or inconclusive. Dawson and Lowson274, claimed to have detected catalysis by acetate ion of the hydrolysis of ethyl acetate as early as 1927, but the extent of catalysis observed was too small to rule out the possibility that salt or solvent effects were, in fact, responsible. 

Ketones and esters are required for C-type inks. Types of esters are ethyl acetate, isopropyl acetate, normal propyl acetate, and butyl acetate. From the ketone class, acetone or methyl ethyl ketone (MEK) can be used. The usual solvent for D-type inks are mixtures of an alcohol, such as ethyl alcohol or isopropyl alcohol, with either aliphatic or aromatic hydrocarbons. Commonly used mixtures are 50/50 blends by volume of alcohol and aliphatic... 

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