CO2 as a monomer for the phosgene-free synthesis of new polycarbonates : catalyst development, mechanistic investigations and monomer screening Citation for published version (APA): Meerendonk, van, W. J. (2005). CO2 as a monomer for the phosgene-free synthesis of new polycarbonates : catalyst development, mechanistic investigations and monomer screening. Technische Universiteit Eindhoven. https://doi.org/10.6100/IR596016 DOI: 10.6100/IR596016 Document status and date: Published: 01/01/2005 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. 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If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 02. Oct. 2021 CO2 as a Monomer for the Phosgene-free Synthesis of New Polycarbonates Catalyst Development, Mechanistic Investigations and Monomer Screening Wouter Johannes van Meerendonk - 1 - The cover picture shows the result of the first successful copolymerization of cyclohexene oxide and CO2 in the high pressure reactor. CIP-DATA LIBRARY TECHNISCHE UNIVERSITEIT EINDHOVEN Meerendonk, Wouter J. van CO2 as a Monomer for the Phosgene-free Synthesis of New Polycarbonates : Catalyst Development, Mechanistic Investigations and Monomer Screening / by Wouter J. van Meerendonk. – Eindhoven : Technische Universiteit Eindhoven, 2005. Proefschrift. – ISBN 90-386-2797-1 NUR 913 Subject headings: copolymerization / polycarbonate ; preparation / polymerization catalysts ; zinc / carbon dioxide / epoxides ; oxiranes / mass spectrometry ; MALDI-ToF-MS / chain transfer Trefwoorden: copolymerizatie / polycarbonaat ; bereiding / polymerisatiekatalysatoren ; zinc / koolstof dioxide / epoxiden ; oxiranen / massaspectrometrie ; MALDI-ToF / ketenoverdracht © 2005, Wouter J. van Meerendonk Printed by PrintService Ipskamp, The Netherlands. Cover design by Ronald Korporaal, Heerenveen, [email protected] This project forms part of the research program of the Dutch Polymer Institute (DPI), Engineering Plastics, DPI project #286. An electronic copy of this thesis is available from the Eindhoven University Library in PDF format (www.tue.nl/bib). - 2 - CO2 as a Monomer for the Phosgene-free Synthesis of New Polycarbonates Catalyst Development, Mechanistic Investigations and Monomer Screening PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Technische Universiteit Eindhoven, op gezag van de Rector Magnificus, prof.dr.ir. C.J. van Duijn, voor een commissie aangewezen door het College voor Promoties in het openbaar te verdedigen op maandag 17 oktober 2005 om 16.00 uur door Wouter Johannes van Meerendonk geboren te Amersfoort - 3 - Dit proefschrift is goedgekeurd door de promotoren: prof.dr. C.E. Koning en prof.dr. G.J.M. Gruter Copromotor: dr. R. Duchateau - 4 - “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I found it!) but ‘That's funny ...’” - Isaac Asimov - 5 - Table of Contents Glossary of symbols and abbreviations 9 Chapter 1 Introduction 11 1.1 Chemical routes to polycarbonates 11 1.2 Aim of this study 12 1.3 Outline of this thesis 13 1.4 References 15 Chapter 2 Literature overview 17 2.1 The monomers 17 2.2 Homopolymerization of oxiranes 19 2.3 Coupling of oxiranes with CO2 25 2.4 Copolymerization of oxiranes with CO2 26 2.5 Known catalysts for the copolymerizations of oxiranes with CO2 29 2.6 Other oxirane monomers 45 2.7 Summary and outlook 46 2.8 References 47 Chapter 3 Silsesquioxane zinc catalysts for the alternating copolymerization of cyclohexene oxide and carbon dioxide 55 3.1 Introduction 55 3.2 Results and discussion 58 3.3 Experimental section 70 3.4 Acknowledgements 74 3.5 References 74 Chapter 4 High throughput and mechanistic studies of zinc catalysts 79 4.1 Introduction 79 4.2 Results and discussion 81 4.3 Concluding remarks 96 4.4 Experimental section 97 4.5 Acknowledgements 100 4.6 References 101 - 6 - Chapter 5 Alternative monomers for polycarbonate synthesis 105 5.1 Introduction 105 5.2 Results and discussion 107 5.3 Concluding remarks 127 5.4 Experimental section 128 5.5 Acknowledgements 132 5.6 References 133 Chapter 6 Physical properties of compression molded parts and coatings of aliphatic polycarbonates 135 6.1 Introduction 135 6.2 Results and discussion 137 6.3 Concluding remarks 146 6.4 Experimental section 146 6.5 Acknowledgements 149 6.6 References 149 Chapter 7 Epilogue and technology assessment 151 Appendix A Lab scale reactor setup 153 A-1 Introduction 153 A-2 Communication and software setup 154 A-3 LabVIEW 155 A-4 Webcam 156 A-5 References 157 Summary 159 Samenvatting 161 Dankwoord 165 Curriculum Vitae 167 Scientific papers 167 - 7 - Glossary of symbols and abbreviations BDI β-diketiminate ligand CHO Cyclohexene oxide DCM Dichloromethane DMA (or DMTA) Dynamic mechanical (thermal) analysis DMSO Dimethylsulfoxide DSC Differential Scanning Calorimetry EO Ethylene oxide I intensity (% or arbitrary units) M+ Cationization agent (MALDI-ToF-MS analyses) MALDI-ToF-MS Matrix-Assisted-Laser-Desorption-Ionization Time-of-Flight Mass- Spectrometry MPVO Meerwein-Ponndorf-Verley reduction/Oppenauer oxidation MWD Molecular weight distribution M n Number averaged molar mass M w Weight averaged molar mass n Number of repeating units in a polymer chain PCHC Poly(cyclohexene carbonate) PCHO Poly(cyclohexene oxide) PCy3 Tricyclohexyl phosphine PDI Polydispersity index PEO Poly(ethylene oxide) PO Propylene oxide PPC Poly(propylene carbonate) PPO Poly(propylene oxide) PS Polystyrene ROP Ring-Opening Polymerization SEC Size Exclusion Chromatography T Temperature (ºC) TGA Thermogravimetric analyses Tpp Tetraphenyl porphyrin Tg Polymer glass transition temperature (ºC) Tm Polymer melt transition temperature (ºC) - 9 - Chapter 1 Introduction 1.1 Chemical routes to polycarbonates With a global annual demand exceeding 1.5 million tons, polycarbonates form a commercially important class of polymers.1 Due to their toughness and optical clarity, they are widely used for structural parts, impact-resistant glazing, streetlight globes, household appliance parts, components of electrical/electronic devices, compact discs, automotive applications, reusable bottles, food and drink containers, and many other products.2,3 The most important polycarbonate is based on bisphenol-A. Currently, there are two different industrial routes for the synthesis of high molecular weight poly(bisphenol-A carbonate) (BA-PC). The first route involves the interfacial reaction between phosgene and the sodium salt of bisphenol-A in a heterogeneous system. The second route consists of a melt-phase transesterification between a bisphenol-A and diphenyl carbonate (Figure 1-1).1 O + NaO ONa Cl Cl O O O O + HO OH n PhO OPh Figure 1-1. Industrial routes to poly(bisphenol-A carbonate).1 The first route is environmentally undesirable due to the need of the hazardous dichloromethane and phosgene, and the production of large amounts of NaCl as a side product. The second route requires high temperature in order to remove phenol, the high boiling condensation product of this polymerization reaction. A different approach in synthesizing polycarbonates was demonstrated by Inoue et al. in 1969.4 They reported the alternating copolymerization of an oxirane with carbon dioxide, resulting in an aliphatic polycarbonate as is depicted in Figure 1-2. - 11 - Chapter 1 O O O CO2 OO OO R R' R R' R R' n Figure 1-2. Polycarbonate from the copolymerization of an oxirane with CO2 This approach has several advantages over the current industrial processes. In contrast to the step-growth mechanisms applied in the synthesis of BA-PC, the route reported by Inoue is a chain- growth process. Therefore, in theory, a much better control of molecular weight is feasible and monomer conversions do not have to approach unity in order to obtain high molecular weights. Another advantage is that the used monomers do not possess the safety hazards of the current industrial process based on phosgene. Furthermore, since carbon