INRA, Montpellier SupAgro, UMR 1083 SPO Sciences pour l'Œnologie, 2 Place Viala, 34060 Montpellier, France.
Published: March 2020
AI Article Synopsis
Article Abstract
An improved analytical depolymerization method for characterizing condensed tannins was developed with menthofuran (3,6-dimethyl-4,5,6,7-tetrahydro-1-benzofuran) as the nucleophilic trapping reagent. Herein, menthofuran was compared with routinely used nucleophiles, phloroglucinol and 2-mercaptoethanol. At 30 °C and in the presence of 0.1 M HCl, menthofuran displayed the outstanding ability to enable the fast and full depolymerization of procyanidin B2 using only a 1:1 molar ratio of both reactants. Under the same conditions, phloroglucinol and 2-mercaptoethanol led to a reaction equilibrium with significantly lower conversion yields. Application to commercial tannin extracts showed that a menthofuran-to-extract weight ratio of 1 gave the same yields of procyanidin constitutive units as 10-fold higher molecular equivalent phloroglucinol and 100-fold 2-mercaptoethanol. Finally, guidelines for implementing the menthofuran depolymerization method are proposed to assess the tannin content and composition of extracts as well as of plant materials without prior extraction.
The extensive use and longevity of nylon plastics pose substantial challenges for plastic management, recycling, and pollution control. Depolymerization and monomer recycling are potential solutions for valorizing waste plastics, but they often rely on complex and costly catalysts. Additionally, various additives in nylon plastics can negatively impact the catalyst efficiency.
As global plastic consumption and littering escalate, innovative approaches to sustainable waste management are crucial. Enzymatic depolymerization has emerged as a promising recycling method for polyesters via monomer recovery under mild conditions. However, current research mainly focuses on using a single plastic feedstock, which can only be derived from complex and costly plastic waste sorting.
This study introduces a novel one-pot strategy for the chemical valorization of poly(lactic acid) (PLA), coupling its base-catalyzed depolymerization with the ring-opening polymerization (ROP) of trimethylene carbonate (TMC). The process exploits an eutectic mixture of lactide (LA) and TMC, which lowers the thermal input required for PLA degradation. Using potassium aryloxide (KOArtBu) as a bifunctional catalyst, the PLA is first quickly hydrolyzed into oligomers or lactic acid, which subsequently initiate the slower polymerization of TMC.
This study introduces a novel and sustainable approach using Ionic Liquids (ILs) as a non-innocent solvent that enhances the performance of the basic catalysts to depolymerize polyurethane foam wastes (PUFWs) through hydrolysis, alcoholysis or aminolysis under mild conditions. The system is stable, fully recoverable, and reusable. Hydrolysis of PUFWs can occur in just 2 minutes at 95-98 °C, producing a white polyol that is easily separated and reused in new polyurethane synthesis.
Starch-lipid complexes have attracted widespread attention owing to high anti-digestibility and thermal stability. However, methods to increase the content of starch-lipid complexes are limited. Therefore, this study aims to investigate the effect of atmospheric cold plasma (ACP) treatment for different times (0, 1, 3, 5, and 7 min) on the formation and structure of complexes between maize starch (MS) and lauric acid (LA).
