Cyclic carbonate functional polymer synthesis

Webster, D. C., and Crain, A. L. Synthesis and Applications of Cyclic Carbonate Functional Polymers in Thermosetting Coatings, Progress in Organic Coatings (2000) 275-282. 

Limited information exists in the literature, however, on the homo- or copolymerization of vinyl ethylene carbonate, 1 (VEC or 4-ethenyl-l,3-dioxolane-2-one) for the preparation of cyclic carbonate functional polymers. A few comments regarding polymerization of VEC are given in an early patent [9], In the only reported study of the copolymerization behavior of VEC, Asahara, Seno, and Imai described the copolymerization of VEC with vinyl acetate, styrene, and maleic anhydride and determined reactivity ratios [10. Their results indicated that VEC would copolymerize well with vinyl acetate, but in copolymerizations with styrene, little VEC could be incorporated into the copolymer. VEC appeared to copolymerize with maleic anhydride, however the compositions of the copolymers was not reported. Our goal was to further explore the use of VEC in the synthesis of cyclic carbonate functional polymers. 

Gabriel Rokicki is a chemistry professor at the Faculty of Chemistry, Warsaw University of Technology, Poland, where he received all his academic education (MSc in 1971, PhD in 1989, and tenure professor in 2002). His current scientific activities include synthesis, stmcture, and properties of polymer materials, such as aliphatic polycarbonates, polyurethanes, epoxy resins, and biodegradable polymers. He has devoted a special interest to the use of functional polymers in obtaining specialty ceramic materials as well as to polymer recycling. Earlier major interests included the utilization of carbon dioxide and cyclic carbonates in the synthesis of condensation polymers. Another topic of interest was polymeric ion-sensors based on modified calixarenes. He is the author and coauthor of 160 scientific papers and holds more than 50 patents in the above-mentioned areas. At the Faculty of Chemistry of Warsaw University of Technology, he conducts lectures on polymer chemistry and technology. 

One of the most widely used methods for the synthesis of cyclic polymers of controlled size and narrow dispersity is based on the end-to-end chain coupling of a,co-difunctional linear polymer precursors in highly dilute reaction conditions. This method offers a series of significant advantages it may be used both for polymers with in-chain reactive functions and for systems having no functional groups in their backbone such as saturated carbon-carbon bond polymers. The absence of potentially... 

Around 110 megatons (Mt) of CO2 are annually used in commercial synthesis processes, to produce urea, salicylic acid, cyclic carbonates, and polycarbonates. The largest use is for urea production, which reached around 90 Mt/yr in 1997. In addition to these applications, there are a number of promising reactions currently under study in various laboratories, reactions that differ in the extent to which CO2 is reduced during the chemical transformation. They include the synthesis of commodities and intermediates (acetic acid, methanol, carbonates, cyclic carbonates, and lactones), polymers (polyurethanes, polypyrones) and a variety of functionalized carboxylic acids (propenic acid, 3-hexen-l,6-dioic acid). A more detailed description can be found in the cited review. ... 

The use of carbon dioxide in the synthesis of functional molecules is of considerable interest. An example is the industrially important reaction of epoxides with carbon dioxide to give cyclic carbonates. Also, functionalization of acetylenes and dienes with carbon dioxide on transition metal catalysts gives rise to the formation of cyclic lactones or dicarboxylic acids. The activation of carbon dioxide by metal complexes was reviewed in 1983 . Reactions of carbon dioxide with carbon-carbon bond formation catalyzed by transition metal complexes was reviewed in 1988 ", heterogenous catalytic reactions of carbon dioxide were reviewed in 1995, and the use of carbon dioxide as comonomers for functional polymers was reviewed in 2005. ... 

Vinyl-functional alkylene carbonates, useful in the preparation of polymers that contain alkylene carbonate pendant groups, can also be prepared from GC. Two examples are the reaction of GC with maleic anhydride and acryloyl chloride to produce the acrylate-functional cyclic carbonates (3 and 4, respectively. Scheme 24). Although the transesterification of alkyl esters such as dimethyl maleate or methyl acrylate by reaction with GC represents an obvious means of obtaining the above materials, the temperatures required of such processes (>100°C) result in unwanted polymerization of both the reactant and product species, even in the presence of well-known radical inhibitors such as 2,6-di-tert-butyl-p-cresol or phenothiazine. In addition, the synthesis of vinyl-functional alkylene carbonates is greatly complicated by the fact that such materials cannot be purified by distillation and must be stored at temperatures < 0 ° C in the presence of a... 

Cyclic carbonate chemistry has also proven to be useful for the preparation of branched or cross-linked polymers. First branched (hyperbranched) PCs were synthesized by Bolton and Wooley. In one of the published methods of synthesis of hyperbranched PCs they used chloroformate-type l,l,l-tris(4-hydroxyphenyl) ethane (THPE)-based monomers (Scheme 100). The authors synthesized hyperbranched aromatic PCs by the polymerization of A2B and AB2 monomers, which involved the condensation of chloroformate (Scheme 104) functionalities with tert-butyldimethylsilyl-protected phenols (Scheme 104), facilitated by reactions with silver fluoride. 

Watile, R.A. Deshmukh, K. M. Dhake, K.P. Bhanage, B. M. Efficient Synthesis of Cyclic Carbonate from Carbon Dioxide Using Polymer Anchored Diol functionalized Ionic Liquids as a Highly Active Heterogeneous Catalyst Catal. Sci. Technol. 2012,2,1051-1055. 

Electrochemical synthesis of various cyclic alkylsilanes has been performed similarly113. It should be noted that 5-silaspiro[4,4]nonane is formed despite the high probability of polymer formation due to the high functionality of the silicon. Such high selectivity in the electrochemical ring closure seems to be due to the orientating effect of an electrode in the course of an irreversible reduction of a carbon-halogen bond in the monosilylated intermediate (equations 87 and 88). 

The synthesis and the study of intrinsic properties of well-defined cyclic synthetic polymers are still a challenge in polymer science. Approaches for their preparation were first concentrated on polymers exhibiting linear ring-chain equilibria. This corresponds to polymers containing functional groups in their backbone chain such as poly(dimethylsilox-anes) (PDMSs), polyethers, polyesters, and so forth. The synthesis of cyclic polymers from carbon-carbon chains free... 

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