Polyesters chemical syntheses

Poly(L-malic acid) denotes a family of polyesters derived from L-malic acid as the building unit. By chemical synthesis, three kinds of poly(L-malic acid) have been obtained, depending on the molecular position of the ester bond the a-type(I) [1], the j8-type(II) [2], and the a,j8-mixed-type(III) [3). 

In particular, during the course of commercial polyester development it turned out that the use of highly purified raw materials is of paramount importance. In this respect the same principles apply to laboratory-scale chemical synthesis as those that apply to industrial-scale manufacturing. Polyester syntheses, like most... 

Duda, A. and S. Penczek, Mechanisms of Aliphatic Polyester Formation, Chap. 12 in Biopolymers, Vol. 3b PolyestersII Properties and Chemical Synthesis, A. Steinbucheland Y. Doi, eds., Wiley-VCH, Weinheim, 2001. 

Intermediate in chemical synthesis coolant lubricant heat-transfer medium polyester dyeing termite-control preparations insecticides... 

Doi, Y. and Steinbiichel, A. (2001) Biopolymers, 3 h Polyesters II-Properties and Chemical Synthesis, Wiley-VCH Verlag GmbH, Weinheim, p. 480. 

The aliphatic polyesters PHB and PLA are generated using different mechanisms of synthesis, PHB by biosynthesis and PLA by chemical synthesis on the basis of biotechnologically generated monomers. 

Examples of books on this topic include (a)Deopura, B.L., Alagirusamy, R., Joshi, M., and Gupta, B. (eds) (2008) Polyesters and Polyamides, Taylor and Francis. (b)Jones, J. (1991) The Chemical Synthesis of Peptides, International Series of Monographs on Chemistry, vol. 23, Oxford Science Publications, Clarendon Press, Oxford. 

A process akin to the allylic oxidation in activation is aromatic side chain oxidation to produce acids or anhydrides. Phthalic anhydride, an important intermediate in production of polyesters, plasticizers, and fine chemicals synthesis, can be produced via selective oxidation of -xylenes using vanadium oxide catalysts (Eqn. 3). This process today accounts for over 85% of the phthalic anhydride produced worldwide, and has largely displaced the partially wasteful and more expensive naphthalene-based route (Eqn. 4), by which nearly all PA was produced in 1960 (Figure 4). Nearly all of the phthalic anhydride produced today is used for manufacturing vinyl plasticizers, with a much smaller application in the fine chemicals industry. 

Finally, polyesters can also be synthesised via enzymatic processes. This type of polymerisations possesses some advantages over the earlier described chemical synthesis routes, including mild reaction conditions, a higher selectivity, a high tolerance of functional groups and the synthesis of pure reaction products which are metal free [79, 80]. However, reaction times are longer and yields lower compared to chain growth polymerisations. 

Produced by classical chemical synthesis using renewable biobased monomers or mixed sources of biomass and petroleum (i.e., polylactic acid or bio-polyester) ... 

Besides these biodegradable polyesters prepared by chemical synthesis, a new class of biodegradable polyesters produced through biotechnology, the poly(alkanoates), is currently under development (see Section 4.2). 

The aluminiun complexes bearing nitrogen-based bidentate or tridentate ligands have recently attracted much attention in fine chemical synthesis and even more in polymerization reactions [57-64]. The synthesis of polyesters by alkoxy aluminum catalyst is attracting a considerable ciu-rent interest. The salalen aluminum complexes 59-63 were prepared (Scheme 6.12) and used for ROP of LA (Table 6.9) [65]. 

Polycaprolactone (PCL) was developed as a biodegradable plastic of aliphatic polyester type derived from the chemical synthesis of crude petroleum [89]. It has a low melting point (ca. 60°C), low viscosity of its melt and it is easy to process [89]. PCL has good water, oil and chlorine resistance. 

In 2011, San Diego-based Genomatica demonstrated industrial-scale microbial production from glucose of 1,4-butanediol, an organic alcohol used around the world in quantities of about 1 million metric tons per year as a solvent and in the manufacture of plastics, polyurethane, polyesters, tetrahydrofuran, and other materials. The conventional chemical synthesis of... 

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