Dibasic acids Saturated

In contrast, equilibrium properties have been successfully discussed in terms of the field effect. Notable instances are those of the ionisation constants of saturated dibasic acids, - and of carboxyl groups held in... 

Polyester Resins. Reinforced polyester resins are thermosets based on unsaturated polyesters from glycols and dibasic acids, either or both of which contain reactive double bonds. The ratio of saturated to unsaturated components controls the degree of cross-linking and thus the rigidity of the product (see Polyesters, unsaturated). Typically, the glycols and acids are esterified until a viscous Hquid results, to which an inhibitor is added to prevent premature gelation. Addition of the monomer, usually styrene, reduces the viscosity to an easily workable level. 

The liquid phases of polar columns are usually the heat-stable polymers of ethyleneglycol and the dibasic acids, succinic or adipic (Table 12.13). Fatty acids are separated on the basis of both chain length and the degree of unsaturation and some columns are capable of resolving fatty acids with the same chain length but different numbers of double bonds (0-6). The saturated fatty acids show the shortest retention times followed by the monoenoic, dienoic, etc. (Figure 12.19). 

Neutral buffered formalin add 100 mL of 37 0% formalin to 900 mL deionized water, then add 4 g monobasic sodium phosphate and 6.5 g dibasic sodium phosphate. Bonin s fluid Combine 1500 mL picric acid (saturated in deionized water at 21 g/L), 500 mL formalin, and 100 mL glacial acetic acid. 

Neutralization.—The preparation of reducing salts by neutralization requires no special comment. The most familiar examples are the soluble sulfites and sulfides. Since these are salts of weak, dibasic acids, it is not satisfactory to rely upon indicators for neutrality. The usual procedure is to prepare a solution of the base and divide it into two equal parts. One of these is saturated with the acid, producing the acid salt, and the other portion is then added, with the formation of the normal salt (example, preparation of (NH4)2S as a laboratory reagent). 

The purity of lanolin and standard tests have been described in the European Pharmacopoeia (EP), in The United States Pharmacopoeia (USP), and according to other national standards.13,14 Lanolin is a semisolid with a melting point of approximately 40 6°C and has a molecular weight in the range of 790 to 880 Da. Lanolin is a complex and variable mixture of mainly esters, diesters, hydroxy esters (87.0-93.5%, w/w),7 8 15 lanolin alcohols (6.0-12.5%, w/w), lanolin acids (<0.5%, w/w), and lanolin hydrocarbons (<1.0%, w/w). The latter are also called paraffins and petrolatum by the EP and USP, respectively.13,14 16-18 Approximately 40% of the esters are a-hydroxy esters. Due to the extremely complex nature of lanolin, the true number of different esters present is unknown. Barnett calculated the theoretical number of monoester combinations from random combinations of 69 aliphatic lanolin alcohols, 6 sterols, and 138 saturated lanolin acids to total 10,350.8 This is most probably an underestimate of the total number of esters, as dibasic acids and dihydric alcohols also occur naturally in lanolin.19 Further combinations of cyclic mono- and di-esters may be formed by dehydration and from inter- and intra-esterification due to heating during the manufacturing process.7 8... 

On the other heind, the linear unsaturated polyester resins find use in memy commercial applications, such as in producing solventless lacquers, and thermosetting molding compounds. The resin is normally prepcured by the reaction of a saturated diol with a mixture of an unsaturated dibasic acid and a modifying dibasic acid or its corresponding anhydride. It is commonly referred to as... 

Van Wijk and Seeder s viscosity equation, 91 vapour, density of saturated, 324 specific heat of saturated, 336, 346-7, 359 vapour pressure 226 alignment chart, 271 of aliphatic esters, 286 of alkali halides, 237,243 of benzene, 267 boiling-point method for, 235 in capillary tubes, 367 of carbon, 246 centri fugal force, effect of, on 292 constant, 335, 341 over curved surface, 366 determination of, 227-47 dew-point method, 241 of dibasic acids, 243 dynamical method, 235 effusion method, 241. electrification, effect of on, 238, 375 of elements 257 of esters, 250 f., 286 of fusible metal, 230 in... 

The unsaturated dibasic acids bear the same relation to the saturated dibasic acids, just considered, as the unsaturated mono-basic acids, acrylic acid, crotonic acid, etc. (p. 172), do to the saturated monobasic acids, acetic acid, etc. They are also the oxidation products of the unsaturated hydrocarbons, alcohols, and aldehydes just as oxalic and succinic acids are of the corresponding saturated compounds. As the simplest dibasic acid containing an ethylene unsaturated group will contain two carboxyl groups and also two doubly linked carbon atoms there must be at least four carbons in the compound. This compound will therefore correspond to succinic acid of the saturated series. Now succinic acid may be derived from either butane by oxidation or from ethane by substitution. Similarly the corresponding unsaturated acid may be derived from butene by oxidation or from ethene by substitution. All of these general relationships may be represented as follows ... 

The USPNF 23 describes dibutyl sebacate as consisting of the esters of n-butyl alcohol and saturated dibasic acids, principally sebacic acid. 

In initial attempts by Johnson and co-workers " to convert the furtiirylidene ketone (5) into the dibasic acid (6) by ozonization, a reaction which with saturated steroids proceeds in excellent yield, yields were low and variable, probably because excess... 

CH3OOC(CH2)nCOOCH3. An ester of a 13-carbon saturated aliphatic dibasic acid. Waxy, low-melting solid, made by an ozone oxidation process. Use Preparation of ethylene brassylate, a synthetic musk chemical intermediate. 

HOOCC10H20COOH. A 12-carbon, straight-chain, saturated aliphatic dibasic acid. 

This sequence of reactions resembles the production of C02 and hydrocarbons when carboxylate ions are discharged at an anode, as in the Kolbe synthesis. Certain acids such as acetic (23, 24) give low yields of C02 on irradiation, and tend to form H2 plus dibasic acids, while radiation-induced carboxylation is observed when COo-saturated aqueous solutions of some organic compounds are irradiated (25, 26, 33). Appreciable yields of C02 are observed either when the resulting radical R is resonance-stabilized or when the alternative reaction is unlikely for steric reasons acids possessing no C-H groupings—e.g., tetrahydroxysuccinic acid—are very reactive towards OH radicals. 

The elements of this group are bivalent or quadrivalent. The saturated oxid of each is the anhydrid of a dibasic acid. They are both combustible, and each occurs in three allotropic forms. 

The saturated dibasic acids fall into a homologous series having the general formula CnIl2n-204. The following table gives a list of some of the dibasic acids which contain the carbon atoms in a straight chain —... 

Fumaric and Maleic Acids, C2H2(COOH)2.—The unsaturated dibasic acids stand in the same relation to the unsaturated hydrocarbons as do the saturated acids to the paraffins. In both cases the acids may be considered as substitution products of the hydrocarbons in which hydrogen atoms are replaced by carboxyl groups. The relation is shown by the formulas,—... 

The unsaturated polyester prepolymers are obtained from the condensation of polyhydric alcohols and dibasic acids. The dibasic acid consists of one or more saturated acid and/or unsaturated acid. The saturated acid may be phthalic anhydride, adipic acid, or isophthalic acid, while the unsaturated acid is usually maleic anhydride or fumaric acid. The polyhydric alcohols in common use include glycol (such as ethylene glycol, propylene glycol, diethylene glycol), glycerol, sorbitol, and pentaeiythritol (Equation 5.1). 

Network polyester resins may be categorized into saturated and unsaturated polyesters. Unlike linear saturated polyesters such as PET, which are made from difunctional monomers, saturated polyesters (glyptal) are formed by the reaction of polyols such as glycerol with dibasic acids such as phthalic anhydride. 

Unsaturated network polyesters may be produced by using an unsaturated dibasic acid or glycol or both. Typically the unsaturated dibasic acid, such as maleic anhydride or fumaric acid, is copolymerized with a saturated acid such as phthalic acid and a glycol (e.g., propylene glycol or diethylene glycol). 

Brassylic acid, a 13-caihon saturated dibasic acid, can be derived from the oxidative cleavage of erucic acid and used as a feedstock for the production of nylon (Scheme 1). Brassylic acid is made by ozonolytic cleavage of erucic acid in acetic acid followed by oxidation of the resultant aldehyde by oxygen at elevated temperatures (100°C) to give the diacid. Crystallization from toluene gives a polymer-grade brassylic acid (6). Pilot-scale production of nylon-1313 (7) as well as nylon-613 was found to have exceptionally low sensitivity to moisture, excellent dimensional stability. and dielectric properties. Long-chain nylons of this type have found niche markets in automotive parts. 

First comes the unsaturated polyester resin itself. From Chapters 12 and 15 we should have a clear idea of what is meant by a polyester resin and, in particular, a saturated polyester resin. Although a drying-oil alkyd is, in a sense, an unsaturated polyester resin, the term has come to be applied solely to polyester resins based on components which introduce unsaturation directly into the polyester backbone. This unsaturation must be capable of direct addition copolymerization with vinyl monomers. To give a linear polymer, any of the dibasic acids or dihydric alcohols mentioned in Chapters 12 and 15 may be used, but the resin should include some unsaturated components. These are usually, though not necessarily, acids, e.g. ... 

Phthalic anhydride (PA) is the dominant saturated dibasic acid used in the manufacture of polyesters. Apart from its availability and low cost, it is easy to handle, quite stable up to the temperature at which polyester resins are generally prepared, stable under UV radiation, reduces the... 

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