Ester oligoester

Terephthalate esters, oligoesters of o-phthalic acids, and in general, solid phthalate esters are rarely used because of their high cost. 

Cyclic esters, ring-opening polymerization of, 85-87 Cyclic lactams, 174 Cyclic oligoesters, 31 Cyclic oligomers, 63, 542 formation of, 39... 

Bachmann and Seebach [159] have reported the preparation and characterization of cyclic lactones (MeCHCH2C(0)0)n, where n = 4 and 8. The reaction product between butyl lithium in benzene and the solid polystyrene support PS-C6H4CH2NH2 leads to a lithiated species that can be represented as PS-Cfd bCI 12N11 Li(BuI i)x, where x 4 is active in the ring-opening of the cyclic esters L-lactide, rac-lactide, and 2,5-morpholinediones, leading to their respective cyclic oligoesters and cyclodepsipeptides (Fig. 49) [160]. The... 

Commercially important polyesters, e.g. poly[l-(2-ethylenyl)-2,2,6,6-tetramethyl-4-piperidinylbutane dioate] (146) [190] were synthesized from l-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidines and suitable dicarboxylic acids. Another polymeric HALS was prepared by transesterification of oligoesters of tetramethyl-butane-l,2,3,4-tetracarboxylate with 22,6,6-tetramethyl-4-hydroxypiperidine and 1,10-decanediol [191]. Compound 147 is a similar polyester type HALS. An ester-amide chain is created during esterification of 2-(2,2,6,6-tetramethyl-4-piperidinylamino)ethanol and dimethyl adipate [192]. 

All-trans unsaturated ester oligomers have been synthesized by lipase-catalyzed polymerization of diesters of fumaric acid and 1,4-butanediol.217 No isomerization of the double bond was observed, as opposed to the extensive isomerization found during chemical polycondensations. Crystallinity was found in the enzymatically formed unsaturated oligoesters prepared in acetonitrile, whereas industrial unsaturated polyesters are amorphous. 

Okumara et al. [10] were the first to attempt the enzyme-catalyzed synthesis of oligoesters from a reaction between dicarboxylic acids and diols. Gutman et al. [11] reported the first study on polyester synthesis by enzyme-catalyzed polymerization of A-B type monomers. Two independent groups in 1993 [12, 13] were first to report enzyme-catalyzed ring-opening polymerization (ROP). Their studies focused on 7- and 6-membered unsubstituted cyclic esters, e-caprolactone (e-CL) and 8-valerolactone (8-VL), respectively. 

A. Kozlowska, R. Ukielski, New type of thermoplastic multiblock elastomers—poly(ester-block-amide)s—based on oligoamide 12 and oligoester prepared from dimerized fatty acid, Eur. Polym. J. 40 (2004) 2767-2772. 

Notably, the potentially competing polyester formation [19] by dehydrogenative selfcoupling of diols was not observed under these conditions. This is probably because the intermediate aldehyde reacts preferentially with the amine, which is a better nucleophile than the alcohol, forming a hemiaminal intermediate [14] (rather than a hemiacetal [11]) followed hy its dehydrogenation to the amide (Schemes 1.6 and 1.11). In addition, it should he noted that complex 8 also catalyzes the formation of amides by coupling of esters with amines (Section 1.4.2) [15] hence, even if some ester (or oligoester) were to be initially formed, it would be converted to the polyamide. 

Oligoesters with acrylic ester end groups can be polymerized either directly or in blends with other monomers. The synthesis of the oligoesters from dicarboxylic acid and glycols in Fig. 7 has already been described with similar molar relationships for epoxide and isocyanate curing agents. The hydroxylic end groups are saturated with acrylic acid esters and then polymerized. 

Fig. 7. Synthesis of oligoesters with acrylic ester end groups by esterification with acrylic acid of oligoesters with hydroxylic end groups.

Maleic acid and phthalic acid are used as oligoester components together with bivalent alcohols (e.g., ethylene glycol, 1,4-butanediol) as co-condensation partners. Crosslinking is achieved by copolymerization of styrene, vinyl acetate, diallyl phthalate, acrylonitrile or acrylic ester. Cyclic structures impart a higher glass transition temperature. The aliphatic glycols in the... 

Preparation of macrocyclic oligoesters has so far been achieved by two major approaches [1]. One is condensation of dibasic acid derivatives with glycols or dihalides, and the other is depolymerization of linear polyesters. However, the yield of macrocyclic oligoesters by these methods are generally unsatisfactory, and moreover, the product distribution is mostly controlled by intrinsic thermodynamic factors. In order to overcome these drawbacks, a new procedure using tin derivatives as covalent templates has been proposed recer tly for the synthesis of some macrocyclic tetra-esters [2]. 

For example, it is reported in Ref. [186] on the synthesis of block-copoly-esters and their properties in dependence on the composition and structure of oligoesters. The oligoesters used were oligoformals on the basis of diane with the degree of condensation 10 and oligosulfones on the basis of phenolphtha-lein with the degree of condensation 10. The synthesis has been performed in conditions of acceptor-catalyst polycondensation. 

Synthesis of oligoesters via ionic adduct yield (first step) and through its condensation with ethyleneglycol acrylic esters (second step)... 

Figure 22.28 and Figure 22.29 show, respectively, the H and C-NMR spectra of the oligoesters prepared from epoxidized sunflower oil methyl esters (methyl biodiesel from sunflower oil) and di-l,2-cyclohexanedicarboxylic anhydride using triethylamine as initiator. These materials are soluble in common organic solvents such as acetone, ethanol, tetrahydrofurane, and chloroform, but insoluble in water. Oligoesters from epoxidized biodiesel can be used as intermediate materials for the synthesis of polyelectrolytes by saponification reactions with aqueous solution of sodium or potassium hydroxide at room temperature (Fig. 22.27). The products obtained after saponification present solubility in water. Amphiphilic materials, such as the polyelectrolytes prepared from epoxidized biodiesel, have hydrophobic and hydrophilic segments. They can spontaneously self-organize in a wide variety of structures in aqueous solution. Understanding the dynamics of the formation and transition between the various self-organized structures is important for technological applications.

FIGURE 22.28 H NMR spectrum of the oligoesters prepared from epoxidized sunflower oil methyl esters. 

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