Cyclic carbonate oligomers

It seems reasonable that polyester cyclics could be prepared by an extension of the /wendo-high-dilution [17] chemistry used for the preparation of cyclic carbonate oligomers [18, 19] however, such proved not to be the case. Brunelle et al. showed that the reaction of terephthaloyl chloride (TPC) with diols such as 1,4-butanediol did not occur quickly enough to prevent concentration of acid chlorides from building up during condensation [14]. Even slow addition of equimolar amounts of TPC and butanediol to an amine base (triethylamine, pyridine or dimethylaminopyridine) under anhydrous conditions did not form cyclic oligomers. (The products were identified by comparison to authentic materials isolated from commercial PBT by the method of Wick and Zeitler [9].)... 

AS is very rare for a polymerization process. The only other reported instances of positive AS values are those for the polymerizations of the cyclic octamers of sulfur and selenium and cyclic carbonate oligomers (Sec. 7-5c) [Brunelle et al., 1989]. All other polymerizations involve a decrease in entropy because of the decreased disorder for a polymer relative to its monomer. The positive AS values for the cyclic siloxane, S, and Se probably result from the high degree of flexibility of the linear polymer chains due to the large-sized atoms that they contain. This flexibility leads to greater degrees of freedom in the linear polymer compared to the cyclic monomer. 

Rosenquist NR, Miller KF, inventors. Composite comprising polymerizes cyclic carbonate oligomer. US patent 4,786,710. 1988. 

Ballone P, Jones RO. Equilibrium polymerization of cyclic carbonate oligomers. III. Chain branching and the gel transition. J Chem Phys 2002 117 6841-6851. 

Cyclic Carbonate Oligomers for Ring-Opening Polymerization. 120... 

Polymerization of a cyclic carbonate ester yields a linear polycarbonate [Kuhling et al., 1989 Rokicki, 2000], For example, the cyclic oligomer (m — 2-20 in Eq. 7-85) of the... 

The [2-1-1] fragmentation of the precursors shown in Figure 6.2 also provides a potential route to monocyclic carbon clusters. Thus cyclic dehydro oligomers of diethynyl[4.4.1]propellatetraenes 6a,b incorporated in a fullerene structure have been prepared and their fragmentation was investigated by mass spectrometry [7]. MALDI TOF mass spectra of 6a,b exhibited peaks due to the stepwise loss of the fullerene fragments, leading to the formation of mono-fullerene adducts of C15 and C20. However, the... 

At the same time there is the scarcity of commercially available polyfunctional cyclic carbonates (Structure 4.2). There are several methods for producing polymers or oligomers containing multiple cyclic carbonate groups ... 

ABC, AB2, ACz, and ABD miktoarm copolymers, where A is PEG, B is poly(D-lactide) (P(D)IA), C is poly(L-lactide) (P(L) LA) and D is PS, were prepared via ROP and NMP and their combination. The first step involved coupling of a hydroxyl funaional monomethyl ether PEG oligomer to a carboxylic acid funaional carbonate 23. The cyclic carbonate of the... 

More generally, the use of cyclic carbonate functional oligomers or polymers appears to be very promising in other numerous applications reported mainly in patents [23]. For example, PC can be used for the extraction of metals such as bismuth, cadmium, cerium, cobalt, copper, gold, iridium, iron, lead, mercury, molybdenum, palladium, rhodium, uranium, vanadium, and zinc. Due to its polarity, PC can also be used to make liquid... 

Preparation of high-molar-mass polyesters from cyclic oligomers seems to be a promising route. In literature, many such processes were described. For instance, many cyclic carbonates of bisphenols (mixtures of oligomers) could be polymerized to high-molar-mass polymers. ... 

The structure of the amine catalyst and its concentration proved to be critical to selective formation of cyclic carbonates. Application of EtaN at 0.1 M concentration led to nearly exclusive formation of cyclic oligomers (90%). Examination of other... 

DBU), l,5-diazabicyclo[4.3.0]non-5-ene (DBN), and N, N-dimethylaminopyridine (DMAP) afforded polyether diols containing BPA moiety.It was shown by MALDI-TOF spectrometry and and NMR spectroscopies that the product obtained from 4-tcrt-butylphenol and PC at 150 °C contained some amount of oligomers with carbonate linkages. The authors suggested that phenols were ionized by an organic base to form an active phenol anion which attacked cyclic carbonate monomer to generate intermediate ions that could farther capture proton and react with phenol itself to yield polyether or poly(ether-carbonate). 

The ROP of six-membered cyclic carbonates with nucleophilic initiators is a chain reaction in which, besides initiation and propagation reactions, transesterification reactions can also take place (Scheme 32).Intramolecular nucleophile (e.g., alkoxide) attacks on carbonyl carbon atom (backbiting) lead to cyclic oligomers, while intermolecular transesterifica-tion leads to a change of the macromolecule length with the consequence that, at equilibrium, the most probable distribution of the molecular weight is obtained (Scheme 32). 

The homopolymerization of the most popular six-membered cyclic carbonates (TMC and neopentyl carbonate) using nucleophilic initiators based on Li-, K-, Mg-, A1-, Zn-, and Sn-containing compounds were also studied. The systems containing alkali metals. Mg and Sn, were found to afford during polymerization, besides linear, also cyclic oligomers. This shows that for this group of initiators the... 

Butanediol oligomers polymers with 2,3-bis(hydroxymethyl) butadiene-1,4 cyclic carbonate dimer, 117... 

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