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Synthesis And Characterization Of Zinc And Calcium Complexes Efficient Catalysts For Ring Opening Polymerization Of E Caprolactone And Lactides
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Book Synopsis Synthesis and Characterization of Zinc and Calcium Complexes: Efficient Catalysts for Ring-Opening Polymerization of E-Caprolactone and Lactides by :
Download or read book Synthesis and Characterization of Zinc and Calcium Complexes: Efficient Catalysts for Ring-Opening Polymerization of E-Caprolactone and Lactides written by and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of Single-site Zinc, Magnesium and Calcium Catalyst Precursors for Ring-Opening Polymerization of Lactides by : Khamphee Phomphrai
Download or read book Studies of Single-site Zinc, Magnesium and Calcium Catalyst Precursors for Ring-Opening Polymerization of Lactides written by Khamphee Phomphrai and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The preparation and characterization of a series of closely related magnesium and zinc compounds active for ROP of lactides are reported using three [beta]-diiminate ligands L 1, L 2 and L 3 where L 1 = CH(CMeNC 6 H 3 -2,6- i Pr 2) 2, L 2 = CH(CMeNC 6 H 4 -2- t Bu) 2 and L 3 = CH(CMeNC 6 H 4 -2-OMe) 2 . For the L 1 ligand, L 1 Mg(N i Pr 2)·(THF), L 1 Zn(N i Pr 2), L 1 Mg(O t Bu)·(THF), L 1 Zn(O t Bu) and L 1 Zn(OSiPh 3)·(THF) have been synthesized. All compounds initiate and sustain ROP of lactides. For a related series L 1 MX(THF) n, where n = 0 or 1, the reactivity follows the order M = Mg> Zn and X = O t Bu> N i Pr 2> N(SiMe 3) 2> OSiPh 3 . Heterotactic polylactide (PLA) is produced from ROP of rac-lactide by zinc catalysts in CH 2 Cl 2 . Magnesium catalysts produce atactic and heterotactic PLA in CH 2 Cl 2 and THF, respectively. The resting states for Zn and Mg are proposed to be L 1 Zn(nu 2 -OCHMeC(O)OP) and L 1 Mg(mu-OP) 2 MgL 1 . For the L 2 ligand, L 2 MgN i Pr 2 ·(THF) and L 2 ZnN i Pr 2 are prepared. In solution, L 2 ZnN i Pr 2 exists as a mixture of syn- and anti-rotamers while L 2 MgN i Pr 2 ·(THF) exists only as a syn-rotamer. In the zinc compound, the syn-conformer is shown to be more reactive than the anti-conformer and is responsible for the polymerization. Heterotactic PLA is obtained in CH 2 Cl 2 for the zinc compound and in THF for the magnesium compound. For the L 3 ligand, L 3 MgN(SiMe 3) 2, [L 3 MgO t Bu] 2, L 3 ZnN(SiMe 3) 2, L 3 ZnO i Pr and L 3 CaN(SiMe 3) 2 ·(THF) are prepared. The OMe groups of ligand L 3 show little affinity toward zinc and in the ROP of rac-lactide give PLA with only moderately enhanced heterotactic tetrads. The OMe groups are shown to bind to Mg reversibly and display significant enhancement of heterotactic PLA. The first single-site calcium complexes of L 1 and tris(pyrazolyl/indazolyl)borate ligands are reported and shown to initiate and sustain ROP of lactide: L 1 CaNR 1 2 ·(THF), Tp R2 CaNR 1 2 ·(THF) n, Tp Men CaNR 1 2, (9-BBN)Bp (+)-Cam CaNR 1 2 ·2THF where Tp R2 = [nu 3 -HB(3-R 2 pz) 3], R 1 = SiMe 3, R 2 = t Bu or i Pr, n = 0 or 1, Men = menthone-derived indazole and Cam = camphor-derived indazole. All calcium complexes polymerize rac-lactide in THF giving mostly atactic PLA except for Tp tBu CaNR 1 2 where heterotactic PLA is produced. Tp tBu CaNR 1 2 reacts with 2,6-diisopropylphenol giving Tp tBu Ca(O-2,6- i Pr 2 C 6 H 3). The order of heterotactic selectivity is THF> PO approx CHO> CH 2 Cl 2 . The single-site calcium complexes are not active for ROP of epoxides and the compound Tp tBu Ca(O-2,6- i Pr 2 C 6 H 3)·(PO) is reported and structurally characterized by a single crystal X-ray diffraction study.
Book Synopsis New High-activity Zinc(II)-based Catalysts for Ring-opening Polymerization by : Ming Cheng
Download or read book New High-activity Zinc(II)-based Catalysts for Ring-opening Polymerization written by Ming Cheng and published by . This book was released on 2000 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthesis, Characterization and Catalytic Activity Study of Zinc Aminobis(phenolate) Complexes Towards Ring-opening Polymerization of Rac-lactide by : Yi Liu
Download or read book Synthesis, Characterization and Catalytic Activity Study of Zinc Aminobis(phenolate) Complexes Towards Ring-opening Polymerization of Rac-lactide written by Yi Liu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of bimetallic and trimetallic zinc complexes of amino-bis(phenolato) ligands was synthesized and characterized. Bimetallic complexes (ZnEt)2[L1] (1a) and (ZnEt)2[L2] (1b) (where [L1] = n-propylamine-N,N-bis(2-methylene-4,6-di-t-butylphenolate) and [L2] = n-propylamine-N,N-bis(2-methylene-6-t-butyl-4-methylphenolate) were prepared via reaction of the proligands H2[L1] and H2[L2] with ZnEt2 in pentane. A THF adduct (ZnEt)2[L1]·THF (1a·THF) was obtained by using THF as solvent. Treatment of 1a with one or two equiv. of isopropyl alcohol gave a trimetallic zinc complex Zn3(i-PrO)2[L1]2 (2). The catalytic activities of these complexes towards ring-opening polymerization (ROP) of rac-lactide were studied in the absence and presence of benzyl alcohol or isopropyl alcohol. These complexes exhibit moderate to good activity for ROP of rac-lactide both in the melt phase and solution. The influence of catalyst and co-initiator loading were studied and thermodynamic activation parameters were determined. Characterization of the polymers by GPC and MALDI-TOF MS showed controlled and living polymerizations for rac-lactide in the presence of alcohol.
Book Synopsis Zinc Catalysis by : Stephan Enthaler
Download or read book Zinc Catalysis written by Stephan Enthaler and published by John Wiley & Sons. This book was released on 2015-02-17 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the gap in the market for comprehensive coverage of this hot topic, this timely book covers a wide range of organic transformations, e. g. reductions of unsaturated compounds, oxidation reactions, Friedel-Crafts reactions, hydroamination reactions, depolymerizations, transformations of carbon dioxide, oxidative coupling reactions, as well as C-C, C-N, and C-O bond formation reactions. A chapter on the application of zinc catalysts in total synthesis is also included. With its aim of stimulating further research and discussion in the field, this is a valuable reference for professionals in academia and industry wishing to learn about the latest developments.
Book Synopsis Biometal Catalyzed Ring-opening Polymerization of Cyclic Esters by : Osit Karroonnirun
Download or read book Biometal Catalyzed Ring-opening Polymerization of Cyclic Esters written by Osit Karroonnirun and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biodegradable polyesters represent a class of extremely useful polymeric materials for many applications. Among these polyesters, the biodegradable and biocompatible, polylactide is very promising for many applications in both medical and industrial areas. Other biodegradable polymers such as polytrimethylene carbonate, polybutyrolactone, polyvalerolactone, and polycaprolactone can be blended or copolymerized with polylactide to fine tune the properties to fit the needs for their applications. The properties of these polymers and copolymers depend upon the tacticity of the polymers which can be directly controlled by the catalysts used for polymer production. Therefore, it has been of great interest to develop new selective catalytic systems for the ring-opening polymerization of lactide and other cyclic monomers. This dissertation focuses on developing new zinc and aluminum complexes and studying their selectivity and reactivity of these complexes for the ring-opening polymerization of lactide and other cyclic monomers, i.e. trimethylene carbonate, beta-butyrolactone, delta-valerolactone, and epsilon-caprolactone. Herein, aspects of the ring-opening polymerization of lactide and other cyclic monomers utilizing novel zinc and aluminum complexes will be discussed in detail. In the process for the ring-opening polymerization of lactide, chiral zinc half-salen complexes derived from natural amino acids have shown to be very active catalysts for producing polymers with high molecular weight and narrow polydispersities at ambient temperature. The chiral zinc complexes were found to catalyze rac-lactide to heterotactic polylactides with Pr values ranging from 0.68-0.89, depending on the catalyst and reaction temperature employed during the polymerization process. The reactivities of the various catalysts were greatly affected by substituents on the Schiff base ligands, with sterically bulky substituents being rate-enhancing. Furthermore, a series of both chiral and achiral aluminium half-salen complexes have been synthesized and characterized. These aluminum complexes all showed moderate selectivity to the ring-opening polymerization of rac-lactide to produce isotactic polylactide with Pm value up to 0.82 in toluene at 70 degrees C. Moreover, some of the studied aluminum complexes displayed epimerization of rac-lactide to meso-lactide during the polymerization process. Kinetic studies for the ring-opening polymerization of lactide utilizing these zinc and aluminum complexes are included in this dissertation. Along with these studies, the copolymerization of lactide with epsilon-caprolactone and delta-valerolactone will also be presented.
Book Synopsis Biopolymers, Polyesters II - Properties and Chemical Synthesis by : A. Steinbüchel
Download or read book Biopolymers, Polyesters II - Properties and Chemical Synthesis written by A. Steinbüchel and published by Wiley-Blackwell. This book was released on 2001 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volumes 3a, b and 4 focus on polyesters synthesized by bacteria and eukaryotic organisms as well as all aspects of the biosynthesis and metabolism of these biopolymers together with their production and isolation. In addition, these volumes treat various synthetic polyesters and related polymers synthesized by the chemical industry for the manufacture of biodegradable materials. Topics include: polyhydroxyalkanoates, pha granules, non-storage phas, poly(malic acid), cutin, suberin, polyphosphate, polylactides, polyglycolide, polyanhydrides, polyesteramides, aliphatic organic polyesters and related polymers, in vitro synthesis of polyesters, chemical synthesis, biotechnological production by fermentation, isolation from plants, production in transgenic plants, biodegradation.
Book Synopsis Synthesis, Structure and Properties of Poly(lactic acid) by : Maria Laura Di Lorenzo
Download or read book Synthesis, Structure and Properties of Poly(lactic acid) written by Maria Laura Di Lorenzo and published by Springer. This book was released on 2017-10-20 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Advances in Polymer Science presents critical reviews of the present and future trends in polymer and biopolymer science. It covers all areas of research in polymer and biopolymer science including chemistry, physical chemistry, physics, material science.The thematic volumes are addressed to scientists, whether at universities or in industry, who wish to keep abreast of the important advances in the covered topics.Advances in Polymer Science enjoys a longstanding tradition and good reputation in its community. Each volume is dedicated to a current topic, and each review critically surveys one aspect of that topic, to place it within the context of the volume. The volumes typically summarize the significant developments of the last 5 to 10 years and discuss them critically, presenting selected examples, explaining and illustrating the important principles, and bringing together many important references of primary literature. On that basis, future research directions in the area can be discussed. Advances in Polymer Science volumes thus are important references for every polymer scientist, as well as for other scientists interested in polymer science - as an introduction to a neighboring field, or as a compilation of detailed information for the specialist.Review articles for the individual volumes are invited by the volume editors. Single contributions can be specially commissioned.Readership: Polymer scientists, or scientists in related fields interested in polymer and biopolymer science, at universities or in industry, graduate students
Book Synopsis Synthesis and Structures of Tridentate Ketoiminate Zinc Complexes Bearing Trifluoromethyl Substituents that Act as L-lactide Ring Opening Polymerization Catalysts by : Nomaan M. Rezayee
Download or read book Synthesis and Structures of Tridentate Ketoiminate Zinc Complexes Bearing Trifluoromethyl Substituents that Act as L-lactide Ring Opening Polymerization Catalysts written by Nomaan M. Rezayee and published by . This book was released on 2012 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Early Main Group Metal Catalysis by : Sjoerd Harder
Download or read book Early Main Group Metal Catalysis written by Sjoerd Harder and published by John Wiley & Sons. This book was released on 2020-04-06 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early Main Group Metal Catalysis gives a comprehensive overview of catalytic reactions in the presence of group 1 and group 2 metals. Chapters are ordered to reaction type, contain educational elements and deal with concepts illustrated by examples that cover the main developments. After a short introduction on polar organometallic chemistry and synthesis of early main group metal complexes, a variety of catalytic reactions are described, e.g. polymerization of alkenes, hydroamination and phosphination reactions, hydrosilylation, hydroboration and hydrogenation catalysis, as well as enantioselective and Lewis-acid catalysis. The book addresses organic chemists and researchers in industry interested in the state-of-the-art and new possibilities of early main group metal catalysis as well as newcomers to the field. Written by a team of leaders in the field, it is a very welcome addition to the area of main group metal chemistry, and to the field of catalysis.
Book Synopsis Biobased Products from Food Sector Waste by : Teresa Cecchi
Download or read book Biobased Products from Food Sector Waste written by Teresa Cecchi and published by Springer Nature. This book was released on 2021-10-18 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past, food waste has been used to produce biogas and biofuels, fertilizers, and animal feed. Using it as a feedstock for innovative biorefineries is not only an ethical issue but also a smart application of the circular economy. This book explores the zero-waste concept in the thriving biobased sector, proposing technologies and procedures to meet the sustainable development goals. The volume categorizes food waste sources and proposes an impressive number of high value-added compounds (e.g., platform chemicals, enzymes, nutraceuticals, antioxidants, organic acids, phosphate, bioadsorbents, pectin, solvents, and pigments) that can be obtained in a sequential biocascade, via chemical, biochemical, thermal, and physical technologies. The synthesis of bioplastics from food waste, their copolymerization and blending, as well as the production of biocomposites and bionanocomposite with biofillers from food scraps, are presented: eluding the cost of waste disposal, reducing biobased materials price, and avoiding using edible resources as a starting material for biobased items are the main beneficial peculiarities of the process. The Authors illustrate challenging characteristics of new biobased materials, such as their mechanical and physico-chemical features, their biodegradability, compostability, recyclability, chemical compatibility, and barrier properties. The volume also delves into socioeconomic considerations and environmental concerns related to the upcycling of food waste, as well as the safety and life cycle assessment of biobased products. Finally, the authors address how advances in digital technology can make food waste upcycling a negative-cost process and discuss best practices to practically implement the biorefinery concept. Research gaps and needs are suggested, and recommendations for food waste handling and management during this COVID-19 pandemic are provided.
Book Synopsis Aluminum Complexes Supported by Tridentate Aminophenoxide Ligand as Efficient Catalysts for Ring-Opening Polymerization of E- Caprolactone by :
Download or read book Aluminum Complexes Supported by Tridentate Aminophenoxide Ligand as Efficient Catalysts for Ring-Opening Polymerization of E- Caprolactone written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Science and Principles of Biodegradable and Bioresorbable Medical Polymers by : Xiang Cheng Zhang
Download or read book Science and Principles of Biodegradable and Bioresorbable Medical Polymers written by Xiang Cheng Zhang and published by Woodhead Publishing. This book was released on 2016-09-22 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Science and Principles of Biodegradable and Bioresorbable Medical Polymers: Materials and Properties provides a practical guide to the use of biodegradable and bioresorbable polymers for study, research, and applications within medicine. Fundamentals of the basic principles and science behind the use of biodegradable polymers in advanced research and in medical and pharmaceutical applications are presented, as are important new concepts and principles covering materials, properties, and computer modeling, providing the reader with useful tools that will aid their own research, product design, and development. Supported by practical application examples, the scope and contents of the book provide researchers with an important reference and knowledge-based educational and training aid on the basics and fundamentals of these important medical polymers. Provides a practical guide to the fundamentals, synthesis, and processing of bioresorbable polymers in medicine Contains comprehensive coverage of material properties, including unique insights into modeling degradation Written by an eclectic mix of international authors with experience in academia and industry
Book Synopsis Synthetic Biodegradable Polymers by : Bernhard Rieger
Download or read book Synthetic Biodegradable Polymers written by Bernhard Rieger and published by Springer. This book was released on 2014-02-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Salen Metal Complexes as Catalysts for the Synthesis of Polycarbonates from Cyclic Ethers and Carbon Dioxide, by Donald J. Darensbourg.- Material Properties of Poly(Propylene Carbonates), by Gerrit. A. Luinstra and Endres Borchardt.- Poly(3-Hydroxybutyrate) from Carbon Monoxide, by Robert Reichardt and Bernhard Rieger. - Ecoflex® and Ecovio®: Biodegradable, Performance-Enabling Plastics, by K. O. Siegenthaler, A. Künkel, G. Skupin and M. Yamamoto.- Biodegradability of Poly(Vinyl Acetate) and Related Polymers, by Manfred Amann and Oliver Minge.- Recent Developments in Ring-Opening Polymerization of Lactones, by P. Lecomte and C. Jérôme.- Recent Developments in Metal-Catalyzed Ring-Opening Polymerization of Lactides and Glycolides: Preparation of Polylactides, Polyglycolide, and Poly(lactide-co-glycolide), by Saikat Dutta, Wen-Chou Hung, Bor-Hunn Huang and Chu-Chieh Lin.- Bionolle (Polybutylenesuccinate), by Yasushi Ichikawa, Tatsuya Mizukoshi.- Polyurethanes from Renewable Resources, by David A. Babb.-
Download or read book Biopolyesters written by Wolfgang Babel and published by Springer. This book was released on 2003-07-01 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: Living systems synthesize seven different classes of polymers. They provide structure and form for cells and organisms, function as catalysts and energy storage and carry the genetic information. All these polymers possess technically interesting properties. Some of these biopolymers are already used commercially. This special volume of Advances in Biochemical Engineering/Biotechnology comprises 10 chapters. It gives an overview of the water insoluble biopolyesters, in particular of the microbially synthesized poly-hydroxyalkanoate (PHA) family. It reports the state of the art of metabolism, regulation and genetic background, the latest advances made in genetic optimization of bacteria, "construction" of transgenic plants and in vitro synthesis by means of purified enzymes. Furthermore, it describes relevant technologies and evaluates perspectives concerning increasing the economic viability and competitiveness of PHA and discusses applications in medicine, packaging, food and other fields.
Book Synopsis Biodegradable Polyesters by : Stoyko Fakirov
Download or read book Biodegradable Polyesters written by Stoyko Fakirov and published by John Wiley & Sons. This book was released on 2015-04-06 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collating otherwise hard-to-get and recently acquired knowledge in one work, this is a comprehensive reference on the synthesis, properties, characterization, and applications of this eco-friendly class of plastics. A group of internationally renowned researchers offer their first-hand experience and knowledge, dealing exclusively with those biodegradable polyesters that have become increasingly important over the past two decades due to environmental concerns on the one hand and newly-devised applications in the biomedical field on the other. The result is an unparalleled overview for the industrial chemist and materials scientist, as well as for developers and researchers in industry and academia alike.
Book Synopsis Handbook of Ring-Opening Polymerization by : Philippe Dubois
Download or read book Handbook of Ring-Opening Polymerization written by Philippe Dubois and published by John Wiley & Sons. This book was released on 2009-03-02 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive, truly one-stop reference discusses monomers, methods, stereochemistry, industrial applications and more. Chapters written by internationally acclaimed experts in their respective fields cover both basic principles and up-to-date information, ranging from the controlled ring-opening polymerization methods to polymer materials of industrial interest. All main classes of monomers including heterocyclics, cyclic olefins and alkynes, and cycloalkanes, are discussed separately as well as their specificities regarding the ring-opening polymerization techniques, the mechanisms, the degree of control, the properties of the related polymers and their applications. The two last chapters are devoted to the implementation of green chemistry in ring-opening polymerization processes. Of much interest to chemists in academia and industry.
