Open Loop Recycling – Guanidine Iron(II) Polymerization Catalyst for the Depolymerization of Polylactide

Burkart, Lisa; Eith, Alexander; Hoffmann, Alexander; Herres‐Pawlis, Sonja

doi:10.1002/asia.202201195

Cited by 8 publications

(16 citation statements)

References 61 publications

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“…In the above case, a yield value equal to 94% was obtained, using a comparable amount of nucleophile (1.5 equiv) but operating at 120 °C. On the other hand, our conditions proved to be significantly better than the ones applied by Herres-Pawlis et al that achieved a quantitative yield, at 60 °C in the presence of a guanidine Iron(II) catalyst but using the nucleophile with a feeding ratio equal to 1:7 …”

Section: Resultsmentioning

confidence: 60%

“…On the other hand, our conditions proved to be significantly better than the ones applied by Herres-Pawlis et al that achieved a quantitative yield, at 60 °C in the presence of a guanidine Iron(II) catalyst but using the nucleophile with a feeding ratio equal to 1:7. 16 Alkylation of N-Substituted Lactamides. After the optimization of the reaction conditions for the aminolysis of PLA, with the aim to obtain products having potential industrial value, we considered the possibility to alkylate the tertiary amine function of the amides (Schemes 2 and 3) for the obtainment of ammonium salts that, depending on their melting point, could behave as ILs.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…As for alcoholysis, different cases have been reported in which Lewis acids , or ionic liquids , have been used as catalysts. Finally, as for aminolysis, after the first example investigating the transformation of PLA into alanine, by treatment of the polymer in ammonia solution, only few examples concerning the aminolysis of PLA, carried out in the presence of amines, have been reported. − The main products of such processes are N -substituted lactamides, widely applied in the chemical industry. These substrates are normally obtained by dehydrative coupling reactions of lactic acid with amines, carried out under equilibrium conditions, producing a large amount of waste because of the removal of an acid or base catalyst. , Then, the possibility to obtain these chemical intermediates, under mild conditions and avoiding production of a large amount of waste, represents a challenge of the current research in the field of sustainable chemistry.…”

Section: Introductionmentioning

confidence: 99%

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Upcycling of Poly(lactic acid) Waste: A Valuable Strategy to Obtain Ionic Liquids

Raia,

Marullo,

Lazzara

et al. 2023

ACS Sustainable Chem. Eng.

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With the aim to investigate new strategies for upcycling of plastic waste, we performed aminolysis of poly(lactic acid) (PLA), using N,N -dimethylethylenediamine (DMEDA), N , N -dimethylpropylenediamine (DMPDA), and 3-aminopropylimidazole (API) as nucleophiles. The N -substituted lactamides obtained were alkylated by using alkyl halides differing in alkyl chain length, obtaining organic salts that in most cases behaved as ionic liquids (ILs). Both aminolysis of PLA and alkylation of amides were carried out taking into consideration the basic principles of the holistic approach to green chemistry, applied at a laboratory scale, and carefully selecting the nature of the reaction solvent, temperature range, and amount of reagents. Organic salts obtained from the alkylation of N -substituted lactamides were investigated to determine their glass or solid–liquid transitions and their thermal stability. Furthermore, cytotoxicity toward normal lung fibroblasts was also assessed. Data collected show that the proposed strategy represents a valuable protocol to upcycle plastic waste, using it as starting material to obtain alternative solvents of potential industrial relevance.

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Section: Resultsmentioning

confidence: 60%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Upcycling of Poly(lactic acid) Waste: A Valuable Strategy to Obtain Ionic Liquids

Raia,

Marullo,

Lazzara

et al. 2023

ACS Sustainable Chem. Eng.

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“…C1 was therefore tested towards its catalytic activity in the alcoholysis of polylactide (foil, M n =49700 g mol −1 ), producing different value‐added alkyl lactates. To set a benchmark for this study, methanolysis was performed at 60 °C in THF using a catalyst loading of 1 mol %, regarding the maximum polymer ester bonds, with an excess amount of MeOH (7.1 eq) and a stirrer speed of 260 rpm, which is the standard procedure of our group [16d,29] . The formation of the desired product methyl lactate (MeLa) was confirmed via 1 H NMR spectroscopy (Figure S15).…”

Section: Resultsmentioning

confidence: 99%

A Multitool for Circular Economy: Fast Ring‐Opening Polymerization and Chemical Recycling of (Bio)polyesters Using a Single Aliphatic Guanidine Carboxy Zinc Catalyst

et al. 2023

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A new aliphatic hybrid guanidine N,O‐donor ligand (TMGeech) and its zinc chloride complex ([ZnCl2(TMGeech)]) are presented. This complex displays high catalytic activity for the ring‐opening polymerization (ROP) of lactide in toluene, exceeding the toxic industry standard tin octanoate by a factor of 10. The high catalytic activity of [ZnCl2(TMGeech)] is further demonstrated under industrially preferred melt conditions, reaching high lactide conversions within seconds. To bridge the gap towards a sustainable circular (bio)economy, the catalytic activity of [ZnCl2(TMGeech)] for the chemical recycling of polylactide (PLA) by alcoholysis in THF is investigated. Fast production of different value‐added lactates at mild temperatures is demonstrated. Selective PLA degradation from mixtures with polyethylene terephthalate (PET) and a polymer blend, catalyst recycling, and a detailed kinetic analysis are presented. For the first time, chemical recycling of post‐consumer PET producing different value‐added materials is demonstrated using a guanidine‐based zinc catalyst. Therefore, [ZnCl2(TMGeech)] is a promising, highly active multitool, not only to implement a circular (bio)plastics economy, but also to tackle today's ongoing plastics pollution.

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“…[ 76 ] As very recent example for new avenues of upcycling, the aminolysis of PLA to benzyl lactamide was reported. [ 77 ]…”

Section: The Technical and Environmental Aspects Of Pla Productionmentioning

confidence: 99%

Opportunities and Challenges of Establishing a Regional Bio‐based Polylactic Acid Supply Chain

et al. 2023

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Polylactic acid (PLA) is the bioplastic with the highest market share. However, it is mainly produced from first‐generation feedstock and there are various inconsistencies in the literature in terms of its production and recycling processes, carbon footprint, and prices. The aim of this study is to compile and contrast these aspects and investigate second‐generation PLA production from technical, economic, and ecological perspectives simultaneously. The comprehensive analyses also show the chances and challenges of originating a PLA supply chain in a specific region. Herein, the German Federal State of North Rhine‐Westphalia (NRW) has been chosen as a region of interest. In addition to highlighting the industrial capabilities and synergies, the study quantifies and illustrates the locations of different suitable second‐generation feedstocks in the region. However, the identified potentials can be challenged by various obstacles such as the high demand of bioresources, feedstock quality, spatial aspects, and logistics. Furthermore, the substantial price gap between PLA and fossil‐based plastics can also discourage the investors to include PLA on their portfolios. Thus, the study also provides recommendations to overcome these obstacles and promote the regional value chains of bioplastics which may serve as prototype for other regions.

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Open Loop Recycling – Guanidine Iron(II) Polymerization Catalyst for the Depolymerization of Polylactide

Cited by 8 publications

References 61 publications

Upcycling of Poly(lactic acid) Waste: A Valuable Strategy to Obtain Ionic Liquids

Upcycling of Poly(lactic acid) Waste: A Valuable Strategy to Obtain Ionic Liquids

A Multitool for Circular Economy: Fast Ring‐Opening Polymerization and Chemical Recycling of (Bio)polyesters Using a Single Aliphatic Guanidine Carboxy Zinc Catalyst

Opportunities and Challenges of Establishing a Regional Bio‐based Polylactic Acid Supply Chain

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