Remarkably selective formation of macrocyclic aromatic carbonates: versatile new intermediates for the synthesis of aromatic polycarbonates

Brunelle, Daniel J.; Boden, Eugene P.; Shannon, Thomas G.

doi:10.1021/ja00162a049

Cited by 122 publications

(71 citation statements)

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“…The calculations indicate that enthalpy cannot be the sole driving force for polymerization in the phenoxides, and the absence of an exotherm agrees with experimental findings. 10 Entropy changes are likely to play a major role and could be studied further by measuring the temperature dependence of the reaction rate. The computing demands of the DF-based calculations described above rule out their application to long simulations over a range of temperatures, but we are planning an extensive study using a classical force field.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Catalytic Reactions of Living Polymers: Density Functional Study of Reactivity of Phenol and Phenoxides with the Cyclic Tetramer of Polycarbonate

2000

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The reactivity of phenol, lithium phenoxide (LiOPh), and sodium phenoxide (NaOPh) with the cyclic tetramer of bisphenol A polycarbonate (BPA-PC) has been investigated using density functional calculations. The potential energy of the system is computed using a suitable reaction coordinate and relaxing all other degrees of freedom by Car-Parrinello molecular dynamics. Both LiOPh and NaOPh catalyze ring opening with small energy barriers (∆E ) 4.0, 2.5 kcal/mol, respectively) to a chain with a phenyl carbonate at one end and a phenoxide at the other, a "living polymer". The barrier is large for phenol (∆E > 40 kcal/mol), but the total energy differences between the reactants and the chain are very small in all three molecules. We discuss the balance between changes in entropy and energy, and we compute the vibrational properties of metastable intermediate species.

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Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Catalytic Reactions of Living Polymers: Density Functional Study of Reactivity of Phenol and Phenoxides with the Cyclic Tetramer of Polycarbonate

2000

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“…21 Using the 254/285 nm area ratio technique, and doping in authentic linear trimer, we were able to show that the ratio of cyclic to linear oligomer was > 10,000:1 ( Fig. 1).…”

Section: Discovery Of Selective Cyclic Oligomer Formationmentioning

confidence: 93%

Cyclic oligomer chemistry

Brunelle

2008

J. Polym. Sci. A Polym. Chem.

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Cyclic oligomers of engineering plastics such as polycarbonate and aromatic polyesters have been known for some time, being formed at very low levels during commercial manufacture. At GE Global Research, we have devised methods for high-yielding and selective preparation of such cyclic oligomers, that are amenable to commercial manufacture. The mixtures of cyclic oligomers have melting points significantly lower than individual ring sizes, and have very low viscosities in the melt. Ring-opening polymerization using appropriate initiators affords rapid reactions (2-6 min) without measurable exotherm, providing very high-molecularweight polymers and without reaction byproducts. These materials have been scaled to commercial quantities, and have shown to be extremely useful for fabrication of glass and carbon fiber composites with high-fiber fractions.

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“…These trends mirror earlier findings for BPA-polycarbonate (BPA-PC) synthesis. [16] Other catalysts examined under the solvent-free ('bulk') conditions included BEMP, CsF and t BuOK. Similarly to the results described above, both BEMP and CsF provided polysulfates with greater M n than did DBU.…”

Section: Author Manuscriptmentioning

confidence: 99%

SuFEx‐Based Synthesis of Polysulfates

et al. 2014

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A handful of high fidelity reactions are at the core of industrial processes producing polymers in multimillion-ton quantities. Most commodity polymers are synthesized from olefins by forming carbon-carbon backbones, whereas engineering polymers are commonly prepared via condensation reactions of monomers often containing an activated carbonyl group or its equivalent and a suitable nucleophile, thus forming carbon-heteroatom linkages. Polyesters, polyamides, polyurethanes, and polyimides are produced in this manner. Despite the variety of backbone structures, polymers containing sulfur(VI) "-SO 2 -" connectors are virtually absent from the literature and are barely used in industrial applications (with the exception of polysulfones, in which the sulfone group is already present in the monomers [1] ).Unsurprisingly, most reported attempts to synthesize sulfur(VI)-containing polymers relied on reactions mimicking carbonyl group-based condensations, i.e. reactions of sulfonyl chlorides with nucleophiles [2] and, to a much lesser extent, Friedel-Crafts sulfonylations. [3] While polymers obtained by those methods can have attractive properties, such as good thermal and hydrolytic stability and mechanical resilience, [2c-e] the unselective reactivity of sulfur(VI) chlorides, which are susceptible to hydrolysis and participate in redox transformations and radical chlorinations, significantly limit the utility of these methods and materials.Sulfur(VI) fluorides, in particular sulfuryl fluoride (SO 2 F 2 ) and its monofluorinated derivatives, sulfonyl (RSO 2 -F) fluorides, sulfamoyl (R 2 NSO 2 -F) fluorides, and fluorosulfates (ROSO 2 -F) stand in stark contrast to other sulfur(VI) halides. These sulfur oxofluorides are much more hydrolytically stable, redox silent, and do not act as halogenating agents. Nevertheless, their selective reactivity can be revealed when an * fokin@scripps.edu Homepage: http://www.scripps.edu/fokin; sharples@scripps.edu Homepage: http://www.scripps.edu/sharpless. Supporting information for this article is available on the WWW under http://www.angewandte.org or from the authors. The formation of sulfonyl-heteroatom bonds is described in detail in an accompanying article in this issue. [5] In the early 1970s, Firth pioneered the synthesis of poly(arylsulfate) polymers from fluorosulfates of Bisphenol A (BPA), which he obtained from SO 2 F 2 , and disodium salts of the bisphenol. [6] Preparation of these monomers required prolonged heating, and pure high polymer was obtained only after repeated precipitation. Here, we report a simple and straightforward SuFEx-based method for the synthesis of high molecular weight polysulfate polymers from aryl fluorosulfates and aryl silyl ethers under simple and mild reaction conditions. HHS Public AccessReactions of silylated and fluorinated compounds are, of course, well known in organic synthesis [7] and in polymer chemistry. [8] For example, in 1983, Kricheldorf introduced the "silyl method" for the synthesis of polyaryl ethers taking advantage of the str...

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Remarkably selective formation of macrocyclic aromatic carbonates: versatile new intermediates for the synthesis of aromatic polycarbonates

Cited by 122 publications

References 0 publications

Catalytic Reactions of Living Polymers: Density Functional Study of Reactivity of Phenol and Phenoxides with the Cyclic Tetramer of Polycarbonate

Catalytic Reactions of Living Polymers: Density Functional Study of Reactivity of Phenol and Phenoxides with the Cyclic Tetramer of Polycarbonate

Cyclic oligomer chemistry

SuFEx‐Based Synthesis of Polysulfates

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