Dicarboxylic acid amide esters anhydrides

Due to reduction or lack of hydrogen bonding, carbonyl carbon nuclei of amides [313-315], anhydrides [316], esters [310-312], and halides [317] display smaller shift values relative to the parent acids (Tables 4.34 and 4.35). Methyl esterification shieldings are about — 6+1 ppm for mono- and — 1.5 + 1 ppm for diesters, reflecting weaker hydrogen bonding in dicarboxylic acids [316] Taking the methoxy carbon as a /i effect... 

The most important method used in the preparation of polyamides is direct amidation, usually through the intermediate formation of a salt of the diamine and dicarboxylic acid, but without it in the case of aminoacids or for pairs of monomers that do not readily form a salt. Esters can react with diamines to form polyamides with liberation of alcohol or phenol. Diamines can be reacted with diamides yielding polyamides and freeing ammonia. Polyamides have been prepared by acidolysis of acyl derivatives of diamines (compare Section 5.4 for acidolysis in polyester preparation). Bis-anhydrides react with diamines to form polyamides and, if reacted further, polyimides. The low-temperature reaction of acid chlorides with diamines has been used, interfacially or as a solution technique, to prepare certain polyamides (compare Section 5.7 for related reactions in polyester synthesis). 

Polymerization reactions involve the union of a number of similar molecules to form a single complex molecule. A polymer is any compound, each molecule of which is formed out of a number of molecules which are all alike, and which are called monomers. In many cases polsonerization can be reversed and the poisoner be resolved to the monomer. Many polymerization reactions which are of industrial importance involve in the initial stages condensations, that is, reactions in which elimination of water or other simple molecules takes place. Compounds which polymerize have some type of unsaturation in the molecule. Olefins, unsaturated halides, esters, aldehydes, dicarboxylic acids, anhydrides, amino acids and amides are among the important groups of compounds which are used in industrial polymerization reactions. The commercial products produced by polymerization reactions may be conveniently classified into (a) resinotds, or synthetic resins (b) elastomers, which possess rubber-like properties and (c) fibroids, used as textile fibers. Two types of resinoids are illustrated in this experiment Bakelite, formed from phenol and formaldehyde, and methacrylate resin formed from an unsaturated ester. 

The anhydride 1 reverts to the dicarboxylic acid on treatment with warm water." Anhydrous alcohols give the half acid-esters 6, and ammonium hydroxide treatment results in the formation of the half acid-amide 7. 

The addition of 4-aminophenol to compositions used commonly for poly-(ester)s allows the production of poly(ester amide)s. For example, a mixture of 2,6-naphthalene dicarboxylic acid, TPA, BP, HBA, and 4-aminophenol is condensed in the presence of acid anhydride. Such materials exhibit good soldering resistance so that they can be utilized as an electric or electronic material such as electric connectors, sockets for integrated circuits, etc. 

General methods for the synthesis of poly(amide-anhydrides) and poly(amide-esters) based on naturally occurring amino acids were described (Domb et at, 1990). The polymers were synthesized from dicarboxylic acids prepared by amidation of the amino group of an amino acid with a cyclic anhydride, or by the amide coupling of two amino acids with a diacid chloride. Low molecular weight polymers from methylene bis(p-carboxybenzamide) were symthesized by melt condensation (Hartmann et al, 1989). A series of amido containing polyanhydrides based on p-aminobenzoic acid were sy nthesized by melt condensation. The polymers melted at 58 to 177°C and had a molecular weight of 2500 to 12400. 

Nomenclature for carboxylic acids and dicarboxylic acids. Structure and nomenclature for acid halides, anhydrides, esters, and amides. 

There are cyclic esters (known as lactones), cyclic amides (known as lactams), cyclic anhydrides, and cyclic imides. The structures for these derivatives are presented in Chapter 20, Section 20.6.5. The chemical reactions associated with derivatives of dicarboxylic acids are discussed in Chapter 20 as well. 

This chapter will discuss methods for the preparation of esters, acid chlorides, anhydrides, and amides from carboxylic acids, based on acyl substitution reactions. Acyl substitution reactions of carboxylic acid derivatives will include hydrolysis, interconversion of one acid derivative into another, and reactions with strong nucleophiles such as organometallic reagents. In addition, the chemistry of dicarboxylic acid derivatives will be discussed, as well as cyclic esters, amides, and anhydrides. Sulfonic acid derivatives will be introduced as well as sulfate esters and phosphate esters. Finally, nitriles will be shown to be acid derivatives by virtue of their reactivity. 

Chapter 16 (Section 16.6) introduced dicarboxylic acids along with their common and lUPAC names. The common names and the lUPAC names are shown again in Table 20.1 for dicarboxylic acids of C2-C10. This chapter deals with the chemistry of carboxylic acids and their derivatives, and dicarboxylic acids have their acyl halide, ester, anhydride, and amide derivatives. The two carboxylic acid units lead to some interesting structural variations, however. 

Just as simple esters and amides can be made by condensation reactions, polyesters such as Dacron and Mylar are made by reacting diols with dicarboxylic acids (Figure 13.15 A). Similarly, polyamides such as nylon form from amines and carboxylic acids. Starting from anhydrides and amines, polyimides can be formed. These structures tend to be extremely stable, and so are valuable in high temperature applications. 

Dicarboxylic acids 1,2-Dicarboxylic acids, and also 1,2-sulfo-carboxylic acids, as well as their derivatives, esters, amides, and anhydrides, when melted with resorcinol in the presence of anhydrous zinc chloride yield the corresponding fluorescein derivatives (see p. 197). 

A large number of dibasic acids and anhydrides are used in the preparation of poly(ester amide)s. These include terephthalic acid, phthalic anhydride, isophthalic acid, endic endo-cis bicyclo(2,2,10-5)-heptene-2,3-dicarboxylic] anhydride, hydrogenated endic anhydride, maleic anhydride, fumaric acid, dichloromaleic anhydride, itaconic acid, brassylic acid, dimer acid, adipic acid, sebacic acid, succinic acid, trimeUitic anhydride, pyrromellitic anhydride and ethylenediamine tetraacetic acid (EDTA). However, tri- and poly-functional compounds are used only partially and are combined with bifunctional derivatives, or derivatives of previously prepared multifunctional compounds which are subsequently polymerised with bifunctional compounds. 

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