1
|
Nizioł E, Marszałek-Harych A, Zierkiewicz W, John Ł, Ejfler J. Structural subtleties and catalytic activity of sodium aminophenolate complexes in polylactide degradation: towards sustainable waste management solutions. Dalton Trans 2024; 53:12893-12904. [PMID: 38814146 DOI: 10.1039/d4dt01270d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
This study explores the intricate coordination chemistry of sodium aminophenolate species and their significant role in the depolymerization of polylactide (PLA), offering novel insights into catalytic degradation processes. By examining sodium coordination entities, including dimers and larger aggregates such as tetramers, we reveal how structural modifications, particularly the manipulation of steric hindrances, influence the formation and stability of these complexes. The dimers, characterized by a unique four-center core (Na-O-Na-O), serve as a foundational motif, which is further elaborated to obtain complexes with varied coordination environments through strategic ligand design. Our research delves into the lability of the amino arm in these complexes, a critical factor that facilitates the coordination of PLA to the sodium center, thereby initiating the depolymerization process. Moreover, DFT studies have been pivotal in identifying the most energetically favorable structures for catalysis, highlighting a distinct preference for an eight-membered ring motif stabilized by intramolecular hydrogen bonds. This motif not only enhances the catalyst's efficiency but also introduces a novel structural paradigm for sodium-based catalysis in PLA degradation. Experimental validation of the theoretical models was achieved through NMR spectroscopy, which confirmed the formation of the active catalyst forms and monitored the progress of PLA degradation. The study presents a comprehensive analysis of the influence of ligand structure on the catalytic activity, underscoring the importance of the eight-membered ring motif. Furthermore, we demonstrate how varying the steric bulk of substituents on the amino arm affects the catalyst's performance, with benzyl-substituted ligands exhibiting superior activity. Our findings offer a profound understanding of the structural factors governing the catalytic efficiency of sodium aminophenolate complexes in PLA degradation. This research not only advances the field of coordination chemistry but also presents a promising avenue for the development of efficient and environmentally friendly catalysts for polymer degradation.
Collapse
Affiliation(s)
- Edyta Nizioł
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
| | | | - Wiktor Zierkiewicz
- Faculty of Chemistry, Wrocław University of Science and Technology, 27 Wybrzeże Wyspiańskiego, 50-370 Wrocław, Poland
| | - Łukasz John
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
| | - Jolanta Ejfler
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
| |
Collapse
|
2
|
Avella A, Rafi A, Deiana L, Mincheva R, Córdova A, Lo Re G. Organo-Mediated Ring-Opening Polymerization of Ethylene Brassylate from Cellulose Nanofibrils in Reactive Extrusion. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:10727-10738. [PMID: 39055864 PMCID: PMC11267636 DOI: 10.1021/acssuschemeng.4c01309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 07/28/2024]
Abstract
Ethylene brassylate is a renewable macrolactone from castor oil that can be polymerized via ring-opening polymerization (ROP) to obtain a fully biosourced biodegradable polyester. ROP mediated by organometallic catalysts leads to high molar mass poly(ethylene brassylate) (PEB). However, the use of metal-free organocatalysis has several advantages, such as the reduction of toxic and expensive metals. In this work, a novel cellulose nanofibril (CNF)/PEB nanocomposite fabrication process by organocatalysis and reactive extrusion (REx) is disclosed. Here, ROP was carried out via solvent-free REx in the presence of CNFs using organic 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst. Neat or lactate-esterified CNFs (LACNF) were used as initiators to investigate the effect of surface topochemistry on the in situ polymerization and the properties of the nanocomposites. A molar mass of 9 kDa was achieved in the presence of both unmodified and LACNFs with high monomer conversion (>98%) after 30 min reaction in a microcompounder at 130 °C. Tensile analysis showed that both nanofibril types reinforce the matrix and increase its elasticity due to the efficient dispersion obtained through the grafting from polymerization achieved during the REx. Mechanical recycling of the neat polymer and the nanocomposites was proven as a circular solution for the materials' end-of-life and showed that lactate moieties induced some degradation.
Collapse
Affiliation(s)
- Angelica Avella
- Department
of Industrial and Materials Science, Chalmers
University of Technology, Rännvägen 2A, Göteborg 41258, Sweden
| | - Abdolrahim Rafi
- Department
of Natural Sciences, Mid Sweden University, Holmgatan 10, Sundsvall 85170, Sweden
| | - Luca Deiana
- Department
of Natural Sciences, Mid Sweden University, Holmgatan 10, Sundsvall 85170, Sweden
| | - Rosica Mincheva
- Laboratory
of Polymeric and Composite Materials (LPCM), Center of Innovation
and Research in Materials and Polymers (CIRMAP), University of Mons, Mons 7000, Belgium
| | - Armando Córdova
- Department
of Natural Sciences, Mid Sweden University, Holmgatan 10, Sundsvall 85170, Sweden
| | - Giada Lo Re
- Department
of Industrial and Materials Science, Chalmers
University of Technology, Rännvägen 2A, Göteborg 41258, Sweden
| |
Collapse
|
3
|
Liu J, Blosch SE, Volokhova AS, Crater ER, Gallin CF, Moore RB, Matson JB, Byers JA. Using Redox-Switchable Polymerization Catalysis to Synthesize a Chemically Recyclable Thermoplastic Elastomer. Angew Chem Int Ed Engl 2024; 63:e202317699. [PMID: 38168073 PMCID: PMC10873474 DOI: 10.1002/anie.202317699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Indexed: 01/05/2024]
Abstract
In an effort to synthesize chemically recyclable thermoplastic elastomers, a redox-switchable catalytic system was developed to synthesize triblock copolymers containing stiff poly(lactic acid) (PLA) end blocks and a flexible poly(tetrahydrofuran-co-cyclohexene oxide) (poly(THF-co-CHO) copolymer as the mid-block. The orthogonal reactivity induced by changing the oxidation state of the iron-based catalyst enabled the synthesis of the triblock copolymers in a single reaction flask from a mixture of monomers. The triblock copolymers demonstrated improved flexibility compared to poly(l-lactic acid) (PLLA) and thermomechanical properties that resemble thermoplastic elastomers, including a rubbery plateau in the range of -60 to 40 °C. The triblock copolymers containing a higher percentage of THF versus CHO were more flexible, and a blend of triblock copolymers containing PLLA and poly(d-lactic acid) (PDLA) end-blocks resulted in a stereocomplex that further increased polymer flexibility. Besides the low cost of lactide and THF, the sustainability of this new class of triblock copolymers was also supported by their depolymerization, which was achieved by exposing the copolymers sequentially to FeCl3 and ZnCl2 /PEG under reactive distillation conditions.
Collapse
Affiliation(s)
- Jiangwei Liu
- Department of Chemistry, Boston College, Eugene F. Merkert Chemistry Center, 2609 Beacon Street, Chestnut Hill, MA 02467, USA
| | - Sarah E Blosch
- Department of Chemistry, and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Anastasia S Volokhova
- Department of Chemistry, and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Erin R Crater
- Department of Chemistry, and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Connor F Gallin
- Department of Chemistry, Boston College, Eugene F. Merkert Chemistry Center, 2609 Beacon Street, Chestnut Hill, MA 02467, USA
| | - Robert B Moore
- Department of Chemistry, and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - John B Matson
- Department of Chemistry, and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jeffery A Byers
- Department of Chemistry, Boston College, Eugene F. Merkert Chemistry Center, 2609 Beacon Street, Chestnut Hill, MA 02467, USA
| |
Collapse
|
4
|
Zhang Q, Hu C, Li PY, Bai FQ, Pang X, Chen X. Solvent-Promoted Catalyst-Free Recycling of Waste Polyester and Polycarbonate Materials. ACS Macro Lett 2024:151-157. [PMID: 38227974 DOI: 10.1021/acsmacrolett.3c00581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Polymeric materials are indispensable in our daily lives. However, the generation of vast amounts of waste polymers poses significant environmental and ecological challenges. Instead of resorting to landfilling or incineration, strategies for polymer recycling offer a promising approach to mitigate environmental pollution. Pioneering studies have demonstrated the alcoholysis of waste polyesters and polycarbonates; however, these processes typically require the use of catalysts. Moreover, the development of strategies for catalyst removal and recycling is crucial, particularly in some industrial applications. In contrast, we present a catalyst-free method for the alcoholysis of common polyester and polycarbonate materials into small organic molecules. Certain polar organic solvents exhibit remarkable efficiency in polymer degradation under catalyst-free conditions. Employing these polar solvents, both polymer resins and commercially available products could be effectively degraded via alcoholysis. Our design contributes a straightforward route for recycling waste polymeric materials.
Collapse
Affiliation(s)
- Qiao Zhang
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China
| | - Chenyang Hu
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China
| | - Peng-Yuan Li
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
| | - Fu-Quan Bai
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
- Chongqing Research Institute, Jilin University, Chongqing 401120, China
| | - Xuan Pang
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China
| | - Xuesi Chen
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China
| |
Collapse
|
5
|
Rittinghaus RD, Herres-Pawlis S. Catalysts as Key Enablers for the Synthesis of Bioplastics with Sophisticated Architectures. Chemistry 2023; 29:e202202222. [PMID: 36173968 PMCID: PMC10098652 DOI: 10.1002/chem.202202222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Indexed: 01/05/2023]
Abstract
Bioplastics are one of the answers to environmental pollution and linear material flows. The most promising bioplastic polylactide (PLA) is already replacing conventional plastics in a number of applications. The properties of PLA, however, do not fit for all potential application areas, but they can be altered by the introduction of comonomers. The copolymerization of lactide (LA) with other lactones like ϵ-caprolactone (CL) has been established for several years. Nevertheless, controlling copolymerizations remains a challenge due to the high complexity of the system. Copolymerization of LA with other monomer classes is much less investigated, but has the chance to overcome the limitations in material properties that occur when only lactones are used. The crucial factor for all copolymerizations is the catalyst. It dominates the reaction kinetics and determines the resulting microstructure. In this review, copolymerization catalysts for LA are presented divided into catalysts for the synthesis of lactone block copolymers, lactone random copolymers, and multimechanistically synthesized copolymers. The selected catalysts are highlighted either owing to their industrially applicable polymerization conditions or their non-standard mechanism.
Collapse
Affiliation(s)
- Ruth D Rittinghaus
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Sonja Herres-Pawlis
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| |
Collapse
|
6
|
Hermann A, Becker T, Schäfer MA, Hoffmann A, Herres‐Pawlis S. Effective Ligand Design: Zinc Complexes with Guanidine Hydroquinoline Ligands for Fast Lactide Polymerization and Chemical Recycling. CHEMSUSCHEM 2022; 15:e202201075. [PMID: 35803895 PMCID: PMC9795895 DOI: 10.1002/cssc.202201075] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/07/2022] [Indexed: 06/15/2023]
Abstract
In this study, the synthesis of two new guanidine hydroquinoline ligands served as basis for six new zinc guanidine complexes. Two of these complexes showed very high activity in the lactide polymerization under industrial conditions. The lactide polymerization was demonstrated in solution and melt conditions observing high activity and molar masses up to 90 000 g mol-1 . Density functional theory studies elucidated the high activity of the complexes associated with the influence of the ligand backbone and the use of triflate counterions. On the way towards a circular economy, polymerization and depolymerization go hand in hand. So far, guanidine complexes have only shown their good activity in the ring opening polymerization of esters, and guanidine complexes with pure N donors have not been tested in recycling processes. Herein, the excellent ability of zinc guanidine complexes to catalyze both polymerization and depolymerization was demonstrated. The two most promising zinc complexes efficiently mediated the methanolysis of polylactide into methyl lactate under mild reaction conditions.
Collapse
Affiliation(s)
- Alina Hermann
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Tabea Becker
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Martin A. Schäfer
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Alexander Hoffmann
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Sonja Herres‐Pawlis
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| |
Collapse
|
7
|
Bio-Based Plastics Production, Impact and End of Life: A Literature Review and Content Analysis. SUSTAINABILITY 2022. [DOI: 10.3390/su14084855] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The accumulation of plastic wastes is one of the most widely spread problems affecting the environment. The reality that plastics can be made from renewable resources and degrade naturally has prompted academics to think outside the box to develop “better for the environment” items. In this paper, a bibliometric analysis of the scholarly publications related to bio-based plastics within the last 20 years is presented. Annual progression, geographic and research area distribution, and keyword co-occurrence were all examined. Six distinct clusters emerged from keyword analysis, which were further categorized into three directions: production to marketing; impact on the environment, economy, and society; and end-of-life (EoL) options. The major focus was on how to counter the weaknesses and challenges of bio-based plastics and take opportunities using the inherent advantages of bio-based plastics. Comprehensive studies regarding the impact of bio-based plastics on the environment, economy and social sustainability are still deficient. Although there are many promising innovations in this area, most of them are at the research stage. The benefits of bio-based plastics and better EoL options can be enjoyed only after increased production.
Collapse
|
8
|
Fuchs M, Walbeck M, Jagla E, Hoffmann A, Herres-Pawlis S. Guanidine Carboxy Zinc Complexes for the Chemical Recycling of Renewable Polyesters. Chempluschem 2022; 87:e202200029. [DOI: 10.1002/cplu.202200029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/22/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Martin Fuchs
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen Chemistry GERMANY
| | - Marcel Walbeck
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen Chemistry GERMANY
| | - Eveline Jagla
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen Chemistry GERMANY
| | - Alexander Hoffmann
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen Chemistry GERMANY
| | - Sonja Herres-Pawlis
- RWTH Aachen Fakultät 1, Institut für Anorganische Chemie Landoltweg 1 52074 Aachen GERMANY
| |
Collapse
|
9
|
Stewart J, Fuchs M, Payne J, Driscoll O, Kociok-Köhn G, Ward BD, Herres-Pawlis S, Jones MD. Simple Zn(ii) complexes for the production and degradation of polyesters. RSC Adv 2022; 12:1416-1424. [PMID: 35425174 PMCID: PMC8979053 DOI: 10.1039/d1ra09087a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/17/2021] [Indexed: 11/21/2022] Open
Abstract
Nine new complexes based on thioether appended iminophenolate (ONS) ligands have been prepared and fully characterized in solution by NMR spectroscopy. Solid-state structures were also obtained for seven complexes. In solution, all complexes were monomeric. The complexes were highly active for the polymerization of purified rac-lactide ([M] : [Zn] : [BnOH] = 10 000 : 1 : 30 at 180 °C) reaching TOF values up to 250 000 h−1. The kinetics of the polymerization have been probed by in situ Raman spectroscopy. The rate of reaction was dramatically reduced using technical grade rac-lactide with increased initiator loading. To move towards a circular economy, it is vital that catalysts are developed to facilitate chemical recycling of commodity and emerging polymeric materials. In this vein, the complexes have been assessed for their ability to break down poly(lactic acid) and poly(ethylene terephthalate). The results from both the polymerization and degradation reactions are discussed in terms of ligand functionality. Nine new complexes based on thioether appended iminophenolate (ONS) ligands have been prepared and fully characterized in solution by NMR spectroscopy.![]()
Collapse
Affiliation(s)
- Jack Stewart
- Department of Chemistry, University of Bath, Claverton Down, Bath BA27AY, UK
| | - Martin Fuchs
- Lehrstuhl für Bioanorganische Chemie, Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Jack Payne
- Department of Chemistry, University of Bath, Claverton Down, Bath BA27AY, UK
| | - Oliver Driscoll
- Department of Chemistry, University of Bath, Claverton Down, Bath BA27AY, UK
| | | | - Benjamin D. Ward
- Department of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
| | - Sonja Herres-Pawlis
- Lehrstuhl für Bioanorganische Chemie, Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Matthew D. Jones
- Department of Chemistry, University of Bath, Claverton Down, Bath BA27AY, UK
| |
Collapse
|
10
|
Payne J, Jones MD. The Chemical Recycling of Polyesters for a Circular Plastics Economy: Challenges and Emerging Opportunities. CHEMSUSCHEM 2021; 14:4041-4070. [PMID: 33826253 PMCID: PMC8518041 DOI: 10.1002/cssc.202100400] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/01/2021] [Indexed: 05/05/2023]
Abstract
Whilst plastics have played an instrumental role in human development, growing environmental concerns have led to increasing public scrutiny and demands for outright bans. This has stimulated considerable research into renewable alternatives, and more recently, the development of alternative waste management strategies. Herein, the aim was to highlight recent developments in the catalytic chemical recycling of two commercial polyesters, namely poly(lactic acid) (PLA) and poly(ethylene terephthalate) (PET). The concept of chemical recycling is first introduced, and associated opportunities/challenges are discussed within the context of the governing depolymerisation thermodynamics. Chemical recycling methods for PLA and PET are then discussed, with a particular focus on upcycling and the use of metal-based catalysts. Finally, the attention shifts to the emergence of new materials with the potential to modernise the plastics economy. Emerging opportunities and challenges are discussed within the context of industrial feasibility.
Collapse
Affiliation(s)
- Jack Payne
- Centre for Sustainable and Circular TechnologiesUniversity of Bath Claverton DownBathBA2 7AYUK
| | - Matthew D. Jones
- Department of ChemistryUniversity of Bath Claverton DownBathBA2 7AYUK
| |
Collapse
|
11
|
Rittinghaus RD, Karabulut A, Hoffmann A, Herres‐Pawlis S. Nachtaktiv: Eisen‐Guanidin‐Komplex katalysiert ROP auf der schlafenden Seite der ATRP. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ruth D. Rittinghaus
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1a 52074 Aachen Deutschland
| | - Aylin Karabulut
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1a 52074 Aachen Deutschland
| | - Alexander Hoffmann
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1a 52074 Aachen Deutschland
| | - Sonja Herres‐Pawlis
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1a 52074 Aachen Deutschland
| |
Collapse
|
12
|
Rittinghaus RD, Karabulut A, Hoffmann A, Herres‐Pawlis S. Active in Sleep: Iron Guanidine Catalyst Performs ROP on Dormant Side of ATRP. Angew Chem Int Ed Engl 2021; 60:21795-21800. [PMID: 34270162 PMCID: PMC8518923 DOI: 10.1002/anie.202109053] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Indexed: 11/23/2022]
Abstract
Copolymers are the answer to property limitations of homopolymers. In order to use the full variety of monomers available, catalysts active in more than one polymerization mechanism are currently investigated. Iron guanidine catalysts have shown to be extraordinarily active in ROP of lactide and herein prove their versatility by also promoting ATRP of styrene. The presented iron complex is the first polymerizing lactide and styrene simultaneously to a defined block copolymer in a convenient one-pot synthesis. Both mechanisms work hand in hand with ROP using the dominantly present FeII species on the dormant side of the ATRP equilibrium. This orthogonal copolymerization by a benign iron catalyst opens up new pathways to biocompatible polymerization procedures broadening the scope of ATRP applications.
Collapse
Affiliation(s)
- Ruth D. Rittinghaus
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Aylin Karabulut
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Alexander Hoffmann
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| | - Sonja Herres‐Pawlis
- Institute of Inorganic ChemistryRWTH Aachen UniversityLandoltweg 1a52074AachenGermany
| |
Collapse
|
13
|
Affiliation(s)
- Jonathan M. Millican
- Macromolecular Chemistry II, Bavarian Polymer Institute, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Seema Agarwal
- Macromolecular Chemistry II, Bavarian Polymer Institute, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| |
Collapse
|
14
|
Gaston AJ, Greindl Z, Morrison CA, Garden JA. Cooperative Heterometallic Catalysts for Lactide Ring-Opening Polymerization: Combining Aluminum with Divalent Metals. Inorg Chem 2021; 60:2294-2303. [PMID: 33512999 DOI: 10.1021/acs.inorgchem.0c03145] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
While homometallic (salen)Al catalysts display excellent performance in lactide ring-opening polymerization (ROP), heterometallic (salen)Al complexes have yet to be reported. Herein, we describe four heterobimetallic (salen)Al catalysts and show that the choice of the heterometal is key. Cooperative Al/Mg and Al/Zn combinations improved the catalyst activity by a factor of up to 11 compared to the mono-Al analogue, whereas the mono-Mg and mono-Zn analogues were completely inactive. In contrast, Al/Li and Al/Ca heterocombinations stunted the polymerization rate. Kinetic and computational studies suggest that Al/Mg and Al/Zn cooperativity arises from the close intermetallic proximity facilitating chloride bridging (thus enhancing initiation), which promotes a rigid square pyramidal geometry around the Al center and further increases the available monomer coordination sites. This work also translates the use of ab initio molecular dynamics calculations to ROP, introducing a useful method of investigating catalyst flexibility and revealing that ligand strain and molecular rigidity can enhance heterometallic catalyst performance.
Collapse
Affiliation(s)
- Anand J Gaston
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Zoe Greindl
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Carole A Morrison
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Jennifer A Garden
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| |
Collapse
|
15
|
Alberti C, Enthaler S. Depolymerization of End‐of‐Life Poly(lactide) to Lactide via Zinc‐Catalysis. ChemistrySelect 2020. [DOI: 10.1002/slct.202003979] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Christoph Alberti
- Universität Hamburg Institut für Anorganische und Angewandte Chemie Martin-Luther-King-Platz 6 D-20146 Hamburg Germany
| | - Stephan Enthaler
- Universität Hamburg Institut für Anorganische und Angewandte Chemie Martin-Luther-King-Platz 6 D-20146 Hamburg Germany
| |
Collapse
|
16
|
Cheung E, Alberti C, Enthaler S. Chemical Recycling of End-of-Life Poly(lactide) via Zinc-Catalyzed Depolymerization and Polymerization. ChemistryOpen 2020; 9:1224-1228. [PMID: 33304737 PMCID: PMC7705614 DOI: 10.1002/open.202000243] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/12/2020] [Indexed: 01/08/2023] Open
Abstract
The chemical recycling of poly(lactide) was investigated based on depolymerization and polymerization processes. Using methanol as depolymerization reagent and zinc salts as catalyst, poly(lactide) was depolymerized to methyl lactate applying microwave heating. An excellent performance was observed for zinc(II) acetate with turnover frequencies of up to 45000 h-1. In a second step the monomer methyl lactate was converted to (pre)poly(lactide) in the presence of catalytic amounts of zinc salts. Here zinc(II) triflate revealed excellent performance for the polymerization process (yield: 91 %, Mn ∼8970 g/mol). Moreover, the (pre)poly(lactide) was depolymerized to lactide, the industrial relevant molecule for accessing high molecular weight poly(lactide), using zinc(II) acetate as catalyst.
Collapse
Affiliation(s)
- Even Cheung
- Universität HamburgInstitut für Anorganische und Angewandte ChemieMartin-Luther-King-Platz 6D-20146HamburgGermany
| | - Christoph Alberti
- Universität HamburgInstitut für Anorganische und Angewandte ChemieMartin-Luther-King-Platz 6D-20146HamburgGermany
| | - Stephan Enthaler
- Universität HamburgInstitut für Anorganische und Angewandte ChemieMartin-Luther-King-Platz 6D-20146HamburgGermany
| |
Collapse
|
17
|
Goto T, Kishita M, Sun Y, Sako T, Okajima I. Degradation of Polylactic Acid Using Sub-Critical Water for Compost. Polymers (Basel) 2020; 12:polym12112434. [PMID: 33105577 PMCID: PMC7690280 DOI: 10.3390/polym12112434] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/02/2020] [Accepted: 10/09/2020] [Indexed: 01/03/2023] Open
Abstract
Polylactic acid (PLA) is expected to replace many general-purpose plastics, especially those used for food packaging and agricultural mulch. In composting, the degradation speed of PLA is affected by the molecular weight, crystallinity, and microbial activity. PLA with a molecular weight of less than 10,000 has been reported to have higher decomposition rates than those with higher molecular weight. However, PLA degradation generates water-soluble products, including lactic acid, that decrease the pH of soil or compost. As acidification of soil or compost affects farm products, their pH should be controlled. Therefore, a method for determining suitable reaction conditions to achieve ideal decomposition products is necessary. This study aimed to determine suitable reaction conditions for generating preprocessed PLA with a molecular weight lower than 10,000 without producing water-soluble contents. To this end, we investigated the degradation of PLA using sub-critical water. The molecular weight and ratio of water-soluble contents (WSCs) affecting the pH of preprocessed products were evaluated through kinetic analysis, and crystallinity was analyzed through differential scanning calorimetry. Preprocessed PLA was prepared under the determined ideal conditions, and its characteristics in soil were observed. The results showed that the crystallization rate increased with PLA decomposition but remained lower than 30%. In addition, the pH of compost mixed with 40% of preprocessed PLA could be controlled within pH 5.4–5.5 over 90 days. Overall, soil mixed with the preprocessed PLA prepared under the determined ideal conditions remains suitable for plant growth.
Collapse
Affiliation(s)
- Toshiharu Goto
- Innovation Exploring Dept., R&D Business Unit, Maxell, Ltd., Koizumi, Oyamazaki, Otokuni-gun, Kyoto 618-8525, Japan;
- Correspondence: (T.G.); (I.O.); Tel.: +81-80-7964-1899 (T.G.); +81-53-478-1165 (I.O.)
| | - Mikitaka Kishita
- Applied Chemistry and Biochemical Engineering Course, Department of Engineering, Graduate School of Integrated Science and Technology Shizuoka University, Hamamatsu 432-8561, Japan;
| | - Yin Sun
- Innovation Exploring Dept., R&D Business Unit, Maxell, Ltd., Koizumi, Oyamazaki, Otokuni-gun, Kyoto 618-8525, Japan;
| | - Takeshi Sako
- Energy System Section, Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561, Japan;
| | - Idzumi Okajima
- Applied Chemistry and Biochemical Engineering Course, Department of Engineering, Graduate School of Integrated Science and Technology Shizuoka University, Hamamatsu 432-8561, Japan;
- Correspondence: (T.G.); (I.O.); Tel.: +81-80-7964-1899 (T.G.); +81-53-478-1165 (I.O.)
| |
Collapse
|
18
|
Alberti C, Kricheldorf HR, Enthaler S. Application of Bismuth Catalysts for the Methanolysis of End‐of‐Life Poly(lactide). ChemistrySelect 2020. [DOI: 10.1002/slct.202003389] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Christoph Alberti
- Universität Hamburg Institut für Anorganische und Angewandte Chemie Martin-Luther-King-Platz 6 D-20146 Hamburg Germany
| | - Hans Rytger Kricheldorf
- Universität Hamburg Institut für Technische und Makromolekulare Chemie Bundesstr. 45 D-20146 Hamburg Germany
| | - Stephan Enthaler
- Universität Hamburg Institut für Anorganische und Angewandte Chemie Martin-Luther-King-Platz 6 D-20146 Hamburg Germany
| |
Collapse
|
19
|
Abstract
Alkyl lactates are green solvents that are successfully employed in several industries such as pharmaceutical, food and agricultural. They are considered prospective renewable substitutes for petroleum-derived solvents and the opportunity exists to obtain these valuable chemicals from the chemical recycling of waste poly(lactic acid). Alkyl lactates (ethyl lactate, propyl lactate and butyl lactate) were obtained from the catalysed alcoholysis reaction of poly(lactic acid) with the corresponding linear alcohol. Reactions were catalysed by a Zn complex synthesised from an ethylenediamine Schiff base. The reactions were studied in the 50–130 °C range depending on the alcohol, at autogenous pressure. Arrhenius temperature-dependent parameters (activation energies and pre-exponential factors) were estimated for the formation of the lactates. The activation energies (Ea1, Ea2 and Ea−2) for alcoholysis in ethanol were 62.58, 55.61 and 54.11 kJ/mol, respectively. Alcoholysis proceeded fastest in ethanol in comparison to propanol and butanol and reasonable rates can be achieved in temperatures as low as 50 °C. This is a promising reaction that could be used to recycle end-of-life poly(lactic acid) and could help create a circular production economy.
Collapse
|