Terephthalic acid, chiral

A chiral terephthalic acid derivative, 2,5-bis[10-(2-methylbutoxy)decyloxy]ter-ephthalic acid (Fig. 15), with two identical stereogenic centers, has been investigated by De Fey ter et al. [18]. 

The chiral side chain polymers derived from asymmetric esters of terephthalic acid and hydroquinone can form (in a broad temperature range, including ambient temperature) an unusual mesophase (the isotropic smectic phase, IsoSm ) characterized by high transparency and optical isotropy within the visible wavelength range, combined with a hidden layered smectic ordering and some elements of helical superstructure at shorter dimensions of 10 to 250 nm. The short-pitch TGB A model seems to be the most adequate for the mesophase structure. 

P8 M is not the only polymer forming the isotropic smectic phase. To date, we have observed formation of that phase for a half-dozen chiral polymethacrylates and polysiloxanes. Table 5.1 summarizes the chemical structure and phase behavior of synthesized side-chain homopolymers, which carry chirally substituted side chains derived from asymmetric esters of terephthalic acid and hydroquinone. Such a structure with alternating orientation of carboxylic link groups seems to favour the formation of the IsoSm phase, whereas isomeric derivatives of p-hydroxybenzoic acid, where all carboxylic links have the same orientation, form only conventional Sm A and Sm C phases. Molar mass of all the synthesized homo- and copoly(meth)acrylates is within the range of 1 to 2-10 g mol the poiysilox-anes have the average degree of polymerization, p 35. 

Chiral sanidic polyesters derived from copolymerizations of (S,S)-2,5-bis(2-meth-ylbutyloxy)terephthalic acid, 2,5-bis(dode-cyl)terephthalic acids, and 4,4 -dihydroxy-biphenyl have been reported [22]. These... 

Finally, polymer backbone itself can be chiral. The tartaric acid butanediol ester [32] and the ester of terephthalic acid and chirally substituted ethylene glycol [33] shown below seem to be the only examples of side-chain FLCPs having a chiral main chain ... 

Fig. 5. Cholesteric texture obtained by dissolving a chiral compound in copolyester prepared from terephthalic acid, methylhydroquinone and pyro-...

More recently, using the chiral Fe(III) salt Fe(III)(R)-(+)-camphorsulfonate [Fe(III)(R)-HCSA] as chemical oxidant, the direct vapor-phase deposition of optically active PAn/(+)-HCSA films has been achieved on nonconductive substrates such as glass and polyethylene terephthalate). Postpolymerization cyclic voltam-metric and Raman spectral studies showed that these chiral ES films possessed stable electrochemical activity in acidic environments.96... 

Lactic acid is a linear, aliphatic thermoplastic polyester with a rigidity and clarity similar to polystyrene and poly(ethylene terephthalate) (PET Martin and Averous, 2001). It is a hydroxycarboxylic acid having a chiral center on its second carbon. Because of the presence of fxmctional groups in a 3-carbon molecule, a lot of chemical reactivity can be incorporated. The carboxylic acid group is mildly acidic, and the stereochemistry of the second carbon is very important in the PLA chemistry (Garlotta, 2001 Gupta and Kumar, 2007). The major characteristics of lactic acid are presented in Table 14.2. Lactic acid comprises two optical isomers of lactic acid L (+)-lactic acid and D(-)-lactic acid. 

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