Lactones ring-opening polymerization

Synthesis of Block and Graft Copolymers by Combination of (Di)lactones Ring Opening Polymerization with Other Living/Controlled Polymerization Processes... 

Ouhadi T, Hamitou R, Jerome R, Teyssie P (1976) Soluble bimetallic p-oxoalkoxides. 8. Structure and kinetic behavior of the catalytic species in unsubstituted lactone ring-opening polymerization. Macromolecules 9 927-931... 

Mei, Y., Kumar, A., and Gross, R.A. (2002) Probing water-temperature relationships for lipase-catalyzed lactone ring-opening polymerizations. Macromolecules, 35.14, 5444-5448. 

Ethyl glucoside as a multifunctional initiator for enzyme-catalyzed regioselective lactone ring-opening polymerization. J. Am. Chem. Soc.,... 

Inspired by the fmding that HiC is active for polycondensation polymerizations, studies were performed to assess HiC activity for lactone ringopening polymerizations (Scheme 2). HiC-catalyzed ROP was carried out in either bulk or toluene. To determine the relationship between reaction temperature and enzyme activity for lactone ring-opening polymerizations, e-caprolactone (1) in bulk was taken as the model system. 

We conclude this section by citing some examples of ring-opening polymerizations. Table 5.9 lists several examples of ring-opening polymerizations. In addition to the reactions listed, we recall the polymerizations of lactones and lactams exemplified by equations in Table 5.3 and 5.4, respectively. 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

SCHEME 8.11 Ring-opening polymerization of (J-lactones to produce polyhydroxyalkanoates (PHAs). 

FIGURE 2 Polymers that can be derived firom L-serine. (a) Poly-(serine ester) was obtained by ring opening polymerization of N-protected serine-p-lactones (19). (b) Poly(serine imine) has appar-... 

Various cyclic esters have been subjected to hpase-catalyzed ring-opening polymerization. Lipase catalyzed the ring-opening polymerization of 4- to 17-membered non-substituted lactones.In 1993, it was first demonstrated that medium-size lactones, 8-valerolactone (8-VL, six-membered) and e-caprolactone (e-CL, seven-membered), were polymerized by lipases derived from Candida cylindracea, Burkholderia cepacia (lipase BC), Pseudomonas fluorescens (lipase PF), and porcine pancreas (PPL). °... 

Lipase catalysis is often used for enantioselective production of chiral compounds. Lipase induced the enantioselective ring-opening polymerization of racemic lactones. In the lipase-catalyzed polymerization of racemic (3-BL, the enantioselec-tivity was low an enantioselective polymerization of (3-BL occurred by using thermophilic lipase to give (/ )-enriched PHB with 20-37% enantiomeric excess (ee). ... 

Reactive polyesters were enzymatically synthesized. Lipase catalysis chemoselecfively induced the ring-opening polymerization of a lactone having exo-methylene group to produce a polyester having the reactive exo-methylene group in the main chain (Scheme 16). This is in contrast to the anionic... 

Polyester syntheses have been achieved by enzymatic ring-opening polymerization of lactide and lactones with various ring-sizes. Here, we focus not only on these cyclic esters but also other cyclic monomers for lipase-catalyzed ringopening polymerizations. Figure 8 summarizes cyclic monomers for providing polyesters via lipase catalysis. 

Lipase catalyzed the ring-opening polymerization of medium-size lactones, d-valerolactone (<5-VL, six-membered) and -caprolactone (c-CL, seven-mem-bered). Lipases CC, PF and PPL showed high catalytic activity for the polymerization of <5-VL [74,75]. The molecular weight of the polymer obtained in bulk at 60 °C was relatively low (less than 2000). 

Ring-opening polymerization of a-methyl-substituted medium-size lactones, a-methyl-y-valerolactone and a-methyl-c-caprolactone, proceeded by using lipase CA catalyst in bulk [82]. As to (R)- and (S)-3-methyl-4-oxa-6-hexa-nolides (MOHELs), lipase PC induced the polymerization of both isomers. The apparent initial rate of the S-isomer was seven times larger than that of the R-isomer, indicating that the enantioselective polymerization of MOHEL took place through lipase catalysis [83]. 

Enzyme activity for the polymerization of lactones was improved by the immobilization on Celite [93]. Immobilized lipase PF adsorbed on a Celite showed much higher catalytic activity than that before the immobilization. The catalytic activity was further enhanced by the addition of a sugar or poly(ethylene glycol) in the immobilization. Surfactant-coated lipase efficiently polymerized the ring-opening polymerization of lactones in organic solvents [94]. 

An alcohol could initiate the ring-opening polymerization of lactones by lipase catalyst ( initiator method ). In the lipase CA-catalyzed polymerization of DDL using 2-hydroxyethyl methacrylate as initiator, the methacryloyl group was quantitatively introduced at the polymer terminal, yielding the methacryl-type polyester macromonomer [98]. This methodology was expanded to synthesis of co-alkenyl- and alkynyl-type macromonomers by using 5-hexen-l-ol and 5-hexyn-l-ol as initiator. 

The high level of interest in the ring-opening polymerization (ROP) of cyclic esters (lactones) stems from the biocompatibility and biodegradability of their polymers. Resorbable aliphatic... 

Table 2 Ring-opening polymerization of lactones initiated by lanthanide complexes (CL = e-caprolactone LA = lactide TMC = trimethylene carbonate). 

Poly(3-hydroxyalkanoate)s have potential for application to engineering plastics endowed with biodegradable nature. One of the synthetic approaches to the polyesters is the ring-opening polymerization of -substituted /3-lactones which can be effectively produced by ring-expansion carbonylation of epox-... 

Aluminum Alkoxides Mediated Ring Opening Polymerization of Lactones and Lactides... 

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