Acid, 26-Methyl Ester

Figure 3-8 a) The dissociation of substituted benzoic acids (X = substituent), and b) the hydrolysis of benzoic acid methyl esters. 

As a general guide, however, it may be noted that the following have fairly easily recognisable odours methyl and ethyl formate methyl and ethyl acetate (apples) methyl and ethyl benzoate methyl salicylate (oil of winter-green) and ethyl salicylate methyl and ethyl cinnamate. (It is however usually impracticable to distinguish by odour alone between the methyl and ethyl esters of a particular acid.) Methyl and ethyl o. alate, and methyl and ethyl phthalate are almost odourless. Succinic and tartaric esters have faint odours. 

Compounds which dissolve in concentrated sulphuric acid may be further subdivided into those which are soluble in syrupy phosphoric acid (A) and those which are insoluble in this solvent (B) in general, dissolution takes place without the production of appreciable heat or colour. Those in class A include alcohols, esters, aldehydes, methyl ketones and cyclic ketones provided that they contain less than nine carbon atoms. The solubility limit is somewhat lower than this for ethers thus re-propyl ether dissolves in 85 per cent, phosphoric acid but re-butyl ether and anisole do not. Ethyl benzoate and ethyl malonate are insoluble. 

Filtration through an acidic filter aid or siUca removes the last traces of soap from the oil. The finished oil is heated under vacuum to remove small amounts of fatty acid methyl esters. 

Difluoroacetic acid undergoes reactions typical of a carboxylic acid such as forming an ester when heated with an alcohol and sulfuric acid. Typical esters are methyl difluoroacetate [433-53-4], bp, 85.2°C, and ethyl difluoroacetate [454-31-9], bp, 99.2°C. It can also be photochemicaHy chlorinated to chlorodifluoroacetic acid [76-04-0] or brominated in the presence of iron to bromodifluoroacetic acid [667-27-6] (37,38). 

Pectins are generally classed according to their ester content as high methoxyl pectins (>50% of the carboxyl groups esterified) or low methoxyl pectins (<50% of carboxyl groups esterified) (pectic acid, methyl ester [9049-34-1]). Low methoxyl pectins, like algins, require calcium for gelation. 

Physical Properties. The physical properties of cyanoacetic acid [372-09-8] NM7—CH2COOH (28) ate summarized in Table 4. The industrially most important esters ate methyl cyanoacetate [105-34-0] and ethyl cyanoacetate [105-56-6]. Both esters ate miscible with alcohol and ether and immiscible with water. 

Selected physical properties of various methacrylate esters, amides, and derivatives are given in Tables 1—4. Tables 3 and 4 describe more commercially available methacrylic acid derivatives. A2eotrope data for MMA are shown in Table 5 (8). The solubiUty of MMA in water at 25°C is 1.5%. Water solubiUty of longer alkyl methacrylates ranges from slight to insoluble. Some functionalized esters such as 2-dimethylaniinoethyl methacrylate are miscible and/or hydrolyze. The solubiUty of 2-hydroxypropyl methacrylate in water at 25°C is 13%. Vapor—Hquid equiUbrium (VLE) data have been pubHshed on methanol, methyl methacrylate, and methacrylic acid pairs (9), as have solubiUty data for this ternary system (10). VLE data are also available for methyl methacrylate, methacrylic acid, methyl a-hydroxyisobutyrate, methanol, and water, which are the critical components obtained in the commercially important acetone cyanohydrin route to methyl methacrylate (11). 

Amides can be produced from fatty acid methyl esters by reaction with ammonia at 220 °C at 12.4 MPa (1800 psi) pressure. Reaction times are reduced to 1 h by this route however, the fatty acid feedstocks must fkst be converted to methyl esters (21). 

Fatty JicidFster Sulfonates. Fatty acid ester sulfonates (FAES) are generally produced from methyl esters, ie, methyl ester sulfonate (MES) and prepared via sulfonation, followed by bleaching and neutralization, in a relatively difficult and complex process ... 

Regular fatty acid diethanolamides are prepared by heating fatty acid with diethanolamine at 160—180°C for 2—4 h. Superamides are prepared by heating a fatty acid methyl ester with an equimolar amount of diethanolamine at 100—110°C for 2—4 h the methanol formed is distilled off (Table 23). 

Sorbitol is the most important higher polyol used in direct esterification of fatty acids. Esters of sorbitans and sorbitans modified with ethylene oxide are extensively used as surface-active agents. Interesteritication of fatty acid methyl esters with sucrose yields biodegradable detergents, and with starch yields thermoplastic polymers (36). 

Organic Acids and Their Derivatives (Anhydrides, Nitriles, Ureas). Alkyleneamines react with acids, esters, acid anhydrides or acyl hahdes to form amidoamines and polyamides. Various diamides of EDA are prepared from the appropriate methyl ester or acid at moderate temperatures (25,26). 

Acrylic Esters. A procedure has been described for preparation of higher esters from methyl acrylate that illustrates the use of an acid catalyst together with the removal of one of the products by azeotropic distillation (112). Another procedure for the preparation of butyl acrylate, secondary alkyl acrylates, and hydroxyalkyl acrylates using -toluenesulfonic acid as a catalyst has been described (113). Alurninumisopropoxide catalyzes the reaction of amino alcohols with methyl acrylate and methyl methacrylate. A review of the synthesis of acryhc esters by transesterification is given in Reference 114 (see... 

The catalytic hydrogenation of esters is of great commercial importance. It is one of the industrial methods used to produce long-chain fatty alcohols (eg, dodecyl and decyl alcohols) from fatty acid methyl esters (33). The method is also suitable for the conversion of dimethyl 1,4-cyclohexanedicarboxylate [94-60-0] into 1,4-cydohexanedimethanol [105-08-8] an important intermediate in the manufacturing of polyesters. 

The following trivial names have been assigned to the penicillin transformation products shown (6), benzylpenicilloate (7), benzylpenaldic acid (8), D-penicillamine (9), a-methyl D-a-benzylpenicilloate (10), benzylpenillic acid (11), benzylpenillamine (12), benzyl-isopenillic acid (13), benzylpenilloic acid (14), benzylpenilloaldehyde (15), benzylpenicil-lenic acid (16) benzylpenillonic acid methyl ester and (17), dethiobenzylpenicillin methyl ester. 

Azacyclotrideca-2,4,6,8,10,12-hexaene-1 -carboxylic acid, methyl ester H NMR, 7, 717 <78AHC(23)55)... 

Azepine-1-carboxylic acid, methyl ester, tricarbonyliron complex X-ray, 7, 494 <70JCS(B)1783) 4//-Azepine-2-carboxylic acid, 6,7-diphenyl-, methyl ester... 

Aziridine-1-carboxylic acid, methyl ester AGf , 7, 52 <71MI50400)... 

H NMR, 4, 561 <65MI31002> Benzo[b]furan-2-carboxylic acid, methyl ester UV, 4, 589 Benzo[b]furan-3-carboxylic acid, 6-chloro-4,5,7-trifluoro-2-methyl-, ethyl ester C NMR, 4, 568 <72JCS(P2)1733> Benzo[b]furan-3-carboxylic acid, 6-cyano-4,5,7-trifluoro-2-methyl-, ethyl ester C NMR, 4, 568 <72JCS(P2)1733>, 569 <72JCS(P2)1733>... 

H NMR, 4, 561 <720MR(4)343> Benzo[b]furan-4-carboxylic acid, methyl ester UV, 4, 589 (73AJC1059)... 

Furan-2-carboxylic acid, methyl ester C NMR, 4, 565, 566, 567 (75CS(7)211)... 

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