Physical properties esters

Methanogenic bacteria, 158 Methanoic acid, 1,351 Methanolysis, 477, 478 Methods, lUPAC, 249 Methoxystearic acids, 467 Methyl esters, physical properties, 349,350, 351, 353,477 Methyl glucosides, 280 Methyl group, van der Waals radius, 346 a-Methylene group, 484 Methyloctadecanoic acids, crystal structures, 15, 347, 348 Methylsterols in fats, 105 Metridiidae, 147 Micellar solutions, 357 Micrococcus lysodeikticus, 35, 46, 47 Microemulsions, 329-32 Migratory grasshopper, 145 Milk fat, 23,51, 60,113-18,167-69,397, 556-57... 

Farad, definition, 1-23 to 26 Faraday constant, 1-1 to 11 Faraday effect, 12-165 to 178 Fats, composition and properties, 7-9 to 13 Fatty acids and methyl esters, physical properties, 7-7 to 8... 

Table IV,183 summarises the physical properties of a few selected aromatic esters.

The production of both an alcohol and the sodium salt of an acid might easily be confused with the hydrolysis products of an ester (in the above instance benzyl benzoate). Such an error would soon be discovered (e.g., by reference to the b.p. and other physical properties), but it would lead to an unnecessary expenditure of time and energy. The above example, however, emphasises the importance of conducting the class reactions of neutral oxygen-containing compounds in the proper order, viz., (1) aldehydes and ketones, (2) esters and anhydrides, (3) alcohols, and (4) ethers. 

The physical properties of cyanoacetic acid [372-09-8] and two of its ester derivatives are Hsted ia Table 11 (82). The parent acid is a strong organic acid with a dissociation constant at 25°C of 3.36 x 10. It is prepared by the reaction of chloroacetic acid with sodium cyanide. It is hygroscopic and highly soluble ia alcohols and diethyl ether but iasoluble ia both aromatic and aUphatic hydrocarbons. It undergoes typical nitrile and acid reactions but the presence of the nitrile and the carboxyUc acid on the same carbon cause the hydrogens on C-2 to be readily replaced. The resulting malonic acid derivative decarboxylates to a substituted acrylonitrile ... 

Table 11. Some Physical Properties of Cyanoacetic Acid and Methyl and Ethyl Esters ...

Butanediol. 1,4-Butanediol [110-63-4] tetramethylene glycol, 1,4-butylene glycol, was first prepared in 1890 by acid hydrolysis of N,]S3-dinitro-l,4-butanediamine (117). Other early preparations were by reduction of succinaldehyde (118) or succinic esters (119) and by saponification of the diacetate prepared from 1,4-dihalobutanes (120). Catalytic hydrogenation of butynediol, now the principal commercial route, was first described in 1910 (121). Other processes used for commercial manufacture are described in the section on Manufacture. Physical properties of butanediol are Hsted in Table 2. 

The polymeric products can be made to vary widely in physical properties through controlled variation in the ratios of monomers employed in thek preparation, cross-linking, and control of molecular weight. They share common quaHties of high resistance to chemical and environmental attack, excellent clarity, and attractive strength properties (see Acrylic ester polymers). In addition to acryHc acid itself, methyl, ethyl, butyl, isobutyl, and 2-ethylhexyl acrylates are manufactured on a large scale and are available in better than 98—99% purity (4). They usually contain 10—200 ppm of hydroquinone monomethyl ether as polymerization inhibitor. 

Physical properties of acryHc acid and representative derivatives appear in Table 1. Table 2 gives selected properties of commercially important acrylate esters, and Table 3 Hsts the physical properties of many acryHc esters. 

Table 3. Physical Properties of Acrylic Esters, CH7=CHC00R ...

The physical properties of the principal commercial acryhc esters are given ia Table 4. A more comprehensive listing of physical properties, including other less common acrylates, is provided ia the article Acrylic acid and derivatives. 

The physical properties of the monomers must be discussed along with those of the cured polymers because consideration of one without the other presents an incomplete picture. The 2-cyanoacryhc ester monomers are all thin, water-clear Hquids with viscosities of 1 3 mPa-s(=cP). Although a number of the esters have been prepared and characterized, only a relative few are of any significant commercial interest, and, of those, the methyl and ethyl esters by far predominate. The physical properties of the principal monomers are included in Table 1. 

The bulk physical properties of the polymers of the 2-cyanoacryhc esters appear in Table 2. AH of these polymers are soluble in /V-methy1pyrro1idinone, /V,/V-dimethy1foTm amide, and nitromethane. The adhesive bonding properties of typical formulated adhesives are Hsted in Table 3. 

Dibasic Acid Esters. Dibasic acid esters (diesters) are prepared by the reaction of a dibasic acid with an alcohol that contains one reactive hydroxyl group (see Esters, organic). The backbone of the stmcture is formed by the acid. The alcohol radicals are joined to the ends of the acid. The physical properties of the final product can be varied by using different alcohols or acids. Compounds that are typically used are adipic, azelaic, and sebacic acids and 2-ethyIhexyl, 3,5,5-trimethyIhexyl, isodecyl, and tridecyl alcohols. 

Polyol Esters. Polyol esters are formed by the reaction of an alcohol having two or more hydroxyl groups, eg, a polyhydric alcohol and a monobasic acid. In contrast to the diesters, the polyol in the polyol esters forms the backbone of the stmcture and the acid radicals are attached to it. The physical properties maybe varied by using different polyols or acids. Trimethylolpropane [77-99-6] C H O, and pentaerythritol [115-77-5] are... 

Physical Properties. Acetoacetic esters are high boiling Hquids with pleasant odors. Lower A/-aLkylamides are water-soluble Hquids acetoacetamide and acetoacetaryHdes are soHds. 4-Chloroacetoacetates are high boiling lachrymatory Hquids. Some physical properties are Hsted in Tables 3 and 4. 

Physical Properties. Industrially, the most important esters are dimethyl malonate [108-59-8] and diethyl malonate [105-53-3] whose physical properties are summarized in Table 2. Both are sparingly soluble in water (1 g/50 mL for the diethyl ester) and miscible in all proportions with ether and alcohol. 

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). 

ROOC—COOH, are not. The dialkyl esters are characterized by good solvent properties and serve as starting materials in the synthesis of many organic compounds, such as pharmaceuticals, agrochemicals, and fine chemicals (qv). Among the diesters, dimethyl, diethyl, and di- -butyl oxalates are industrially important. Their physical properties are given in Table 7. 

The physical properties of the acids, the most important anhydrides, and the full methyl esters are summarized ia Tables 2, 3, and4. Detailed Hsts of physical properties for phthaUc acid and its anhydride, terephthaUc acid and dimethyl terephthalate, isophthaUc acid, trimeUitic acid and its anhydride, and pyromeUitic acid and its dianhydride/ are provided under the sections describiag these compounds. 

Uses. Phthabc anhydride is used mainly in plasticizers, unsaturated polyesters, and alkyd resins (qv). PhthaUc plasticizers consume 54% of the phthahc anhydride in the United States (33). The plasticizers (qv) are used mainly with poly(vinyl chloride) to produce flexible sheet such as wallpaper and upholstery fabric from normally rigid polymers. The plasticizers are of two types diesters of the same monohydric alcohol such as dibutyl phthalate, or mixed esters of two monohydric alcohols. The largest-volume plasticizer is di(2-ethylhexyl) phthalate [117-81-7] which is known commercially as dioctyl phthalate (DOP) and is the base to which other plasticizers are compared. The important phthahc acid esters and thek physical properties are Hsted in Table 12. The demand for phthahc acid in plasticizers is naturally tied to the growth of the flexible poly(vinyl chloride) market which is large and has been growing steadily. 

Derivatives. In general, the esters of terephthaHc acid derived from saturated alcohols undergo the same reactions as dimethyl terephthalate. Some physical properties of six of these esters are Hsted in Table 23. The di- -butyl and di-2-ethyIhexyl esters find use as plasticizers (qv). Terephthaloyl chloride, which is prepared by reaction of terephthaHc acid and thionyl chloride, is used to prepare derivatives of terephthaHc acid. 

Derivatives. The dual functionaUty of trimellitic anhydride makes it possible to react either the anhydride group, the acid group, or both. Derivatives of trimellitic anhydride include ester, acid esters, acid chloride, amides, and amide—imides (136). Trimellitate esters are the most important derivatives, and physical properties of more significant esters are Hsted in Table 34. 

Acrylic Polymers. Although considerable information on the plasticization of acryUc resins is scattered throughout journal and patent hterature, the subject is compHcated by the fact that acryUc resins constitute a large family of polymers rather than a single polymeric species. An infinite variation in physical properties may be obtained through copolymerization of two or more acryUc monomers selected from the available esters of acryUc and methacryhc acid (30) (see Acrylic esterpolya rs Methacrylic acid and derivatives). 

Monomers such as aUyl methacrylate and diaUyl maleate have appUcations as cross-linking and branching agents selected especiaUy for the different reactivities of their double bonds (90) some physical properties are given in Table 8. These esters are colorless Uquids soluble in most organic Uquids but htde soluble in water DAM and DAF have pungent odors and are skin irritants. 

Physical properties of isopropyl alcohol are characteristic of polar compounds because of the presence of the polar hydroxyl, —OH, group. Isopropyl alcohol is completely miscible ia water and readily soluble ia a number of common organic solvents such as acids, esters, and ketones. It has solubiUty properties similar to those of ethyl alcohol (qv). There is a competition between these two products for many solvent appHcations. Isopropyl alcohol has a slight, pleasant odor resembling a mixture of ethyl alcohol and acetone, but unlike ethyl alcohol, isopropyl alcohol has a bitter, unpotable taste. 

Table 3 gives the corresponding physical properties of some commercially important substituted pyridines having halogen, carboxyHc acid, ester, carboxamide, nitrile, carbiaol, aminomethyl, amino, thiol, and hydroxyl substituents. 

Rosin ester resins are used as modifiers in the formulation of chewing gum. The rosin derivative modifies the physical properties of the polymer used, providing the desired masticatory properties. The glycerol ester of hydrogenated rosin is the predominant choice, because stabilized materials have improved aging resistance, which extends the shelf life of the gum. 

The main commercial apphcations for sahcylate esters are as uv sunscreen agents and as flavor and fragrance agents. Several have apphcation as topical analgesics. A number of sahcylate esters of commercial interest and their physical properties are hsted in Table 8. 

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