Polymerization Of Cyclic Carbonates Research Articles

Digital economy in assessing the investment attractiveness of innovative enterprises based on the results of their own scientific and technical research in the field of petrochemical chemistry

The concept of the digital economy greatly simplifies the solution of multi-criteria choice problems in an innovative environment, in particular, when an economic assessment of the investment attractiveness of a number of enterprise projects with a set of varied in a wide range of technical indicators and commercialization indicators is necessary. Based on the example of small innovative enterprises based on the results of their own scientific and technical research in the field of petrochemical chemistry, a model for the formation of investment portfolios is compiled, taking into account the impact of costs on an improved set of product technical characteristics and the relevance of the level of these characteristics by the investor. The choice of projects from the field of petrochemical chemistry is due to the high importance of this sector both in the economy of individual regions, as the most flexible and at the same time self-sufficient economic system, for example, the Republic of Tatarstan, and at the national and global level. The presence of own scientific developments of the co-author of the article in the field of petrochemical and chemical cluster provides a close relationship of the economic component of innovative projects with variation of all possible technical and technological characteristics of an innovative product in a wide range, depending on investors’ requirements. In addition to traditional applications, the complex of transparent high-strength polymers and polymers with non-stick properties, based on the principles and mechanisms of anionic (co) polymerization of cyclic carbonates with isocyanate-containing compounds under conditions of anionic initiation, gained interest in space technologies, technologies of nano-sized particles and liquid crystals, which requires the search for new methods of synthesis and digital on-line interrelation of the changing costs of the project with its economic efficiency.

A semiempirical study of CO2 elimination in cationic polymerization of cyclic carbonates

The reaction paths of 1,3-dioxan-2-one during cationic ring-opening polymerization have been explored by AM1 semiempirical calculations. A species evolution diagram has been established, and the propagation chain ends on the ether-oxygen of carbonyl functional groups have been identified as the species that ultimately lead to decarboxylation. Three measures were proposed to reduce the degree of decarboxylation based on theoretical calculations: increasing the monomer concentration; decreasing the solvent polarity; and altering the ring substituents so as to bypass the decarboxylation route. Experimental investigations on a number of substituted DOO (including 4-vinyl-1,3-dioxan-2-one and its derivatives) support this conclusion.

Controlled ring‐opening polymerization of cyclic carbonates and lactones by an activated monomer mechanism

AbstractThis article reviews recent topics in the controlled synthesis of polycarbonates and polylactones with small polydispersity indices by activated monomer cationic ring‐opening polymerizations, especially with new initiator systems, such as alcohol/protonic acid and boron alkoxide/protonic acid. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2190–2198, 2002

Living ring-opening polymerization of cyclic carbonates by titanium bisphenolate complexes

Living ring-opening polymerization of cyclic carbonates by titanium bisphenolate complexes

Ring‐opening polymerization of cyclic carbonates by alcohol–acid catalyst

Ring-opening reactions of 1,3-dioxepan-2-one (1) and 1,3-dioxan-2-one (2) with several alcohols were examined. The reactions proceeded without trifluoroacetic acid (TFA) in low conversions, while they proceeded smoothly with TFA to afford the ring-opened adducts and oligomers. Ring-opening polymerizations of 1 and 2 were also carried out by alcohol–acid catalysts to afford the corresponding polycarbonates (Mn = 2500−6800). The molecular weights increased with increase of the conversions of 1 and 2. The observed polymerization rates of 1 and 2 were determined as 24.4 × 10−6 and 0.8 × 10−6 s−1, respectively. Mechanistic aspects were studied by NMR spectroscopy. The methylene protons α and β to the carbonate moieties shifted to lower fields in 0.06–0.11 ppm in the 1H-NMR spectra by the addition of TFA. Downfield shifts of the carbonyl carbon signals of 1 and 2 were observed in 3.94–4.15 ppm in the 13C-NMR spectra. These results strongly suggest that the cyclic carbonates are activated by TFA. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2463–2471, 1998

Living ring‐opening polymerization of cyclic carbonate using cationic zirconocene complex as catalyst

AbstractLiving ring‐opening polymerization of the cyclic carbonate 1,3‐dioxepan‐2‐one was achieved by using the cationic zirconocene complex [Cp2ZrMe]+[B(C6F5)4]− as catalyst at room temperature. A linear relation between conversion and molecular weight of the obtained polymer was observed. Furthermore, block copolymerization of the cyclic carbonate and ε‐caprolactone was successfully performed.

New ring-opening polymerization via a ?-allylpalladium complex

A binary system of a palladium complex as catalyst and zinc alkoxide as initiator conducted a novel ring-opening polymerization of cyclic carbonate, i. e., 5,5-dimethyl-4-ethenyl-1,3-dioxan-2-one. The polymerization proceeded along with releasing carbon dioxide to produce the corresponding polyether. The π-allylpalladium complex generated from the monomer with the catalyst is the key intermediate for this new polymerization. The propagating end is zinc alkoxide, which nucleophilically attacks the monomer activated as the π-allylpalladium complex in the propagation.

First Example of Anionic Polymerization with Azo-Containing Radical Initiators: Anionic Ring-Opening Polymerization of Cyclic Carbonate Initiated by Azobis(isobutyronitrile) and Related Azo Initiators

It is shown that azo initiators such as AIBN are able to initiate anionic polymerization when a vinyl monomer capable of polymerizing readily with an anionic initiator is used.

Ring‐opening polymerization and copolymerization of cyclic carbonates

AbstractThe anionic ring‐opening polymerization may result in a broad variety of homo‐ and copolycarbonates. Upon suitable selection of monomers, polymers with functional groups may be obtained which are eligible to cross‐linking reactions or exert a high degree of hydrophilicity. Copolymers with lactones are readily obtained, provided both polymerization reactions follow the same mechanism; the ring‐opening polymerization of cyclic carbonates is exclusively initiated by alcoholate ions and not by carboxylate anions. Since butyllithium is a suitable Initiator for the ring‐opening anionic polymerization of cyclic carbonates, living vinyl polymers may be used as initiators as well to obtain the respective blockcopolymers. Instead of living vinyl polymers obtained in the conventional manner, using carbanionic Initiators, also living polymers obtained by group transfer polymerization may be used as initiators for the ring‐opening polymerization of cyclic carbonates; the mechanism for the latter polymerization, however, then is rather a non‐metallic anionic one than a group transfer mechanism.

Branched bpa polycarbonates with high shear sensitivity from ring‐opening polymerization of cyclic carbonates

AbstractBranched BPA polycarbonates with high shear sensitivity (i.e. having complex melt viscosity ratios as high as 8.0 or even 10.0) were prepared by ring opening polymerization of cyclic oligomeric BPA carbonates in the melt (at 275 C) with various branching agents [e.g. 1,3,5‐tris(chloromethyl)‐2,4,6‐trimethylbenzene, bis(2,4‐dihydroxyphenyl) sulfide, and 1,1,1‐tris(4‐hydroxyphenyl)ethane]. Furthermore, it was determined that the shear sensitivity is directly related to the branching agent level and inversely related to the level of initiator used in the ring‐opening polymerization.