Fig 4 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Source publication
Plastic materials are indispensable in everyday life because of their versatility, high durability, lightness and cost-effectiveness. As a consequence, worldwide plastic consumption will continue to grow from around 350 million metric tons per annum today to an estimated 1 billion metric tons per annum in 2050. For applications where polymers are a...
Contexts in source publication
Context 1
... fact that glycolic acid is a monomer that can be obtained from CO 2 makes poly(glycolic acid) (PGA) a very appealing polymer from a sustainability standpoint. PGA is the simplest aliphatic polyester, since it possesses a linear molecular structure without any side chains (Fig. ...
Context 2
... first synthesis attempts by Carothers in 1932 [51] did not succeed in the production of high molecular weight polymer. An improved strategy achieving this goal was reported in 1954, with a process to prepare PGA directly from glycolide (GL), the cyclic diester of glycolic acid (Fig. 4b). GL was polymerized to PGA using ring opening polymerization (ROP) [52]. One of the interesting properties of PGA is its relatively facile degradability (2-4 weeks in vivo [53]). This property has resulted in medical applications such as ...
Similar publications
Among methods employed for carbon capture, electroreduction of CO 2 offers not only reducing CO 2 levels but also the possibility of recycling it into commodity chemicals. However, the most efficient catalysts for this reaction are precious metals. In order to achieve cost-effective processes, other elements should be used. Transition-metal atoms c...
Carbon capture and utilization technologies promise to reduce greenhouse gas emissions and abiotic resource depletion while contributing to a circular economy. However, the environmental benefits of carbon capture and utilization technologies need to be proven. Life cycle assessment is the most applied method when it comes to the evaluation of envi...
Citations
... The total production in China, the largest producer, was only 200 kilotons as of 2016. 6) The industrial production of oxalic acid has employed several types of feedstocks including biomass (e.g., sugars), ethylene glycol, carbon monoxide, alkali formates, and propylene. 10) No industrial process uses CO 2 as the feedstock. ...
... Research groups in the EU are aiming at producing oxalic acid and oxalic acid-derived polymers from CO 2 in their European Horizon 2020 project "OCEAN". 6,7) In their research, CO 2 was electrochemically reduced to potassium formate, and the thermal coupling of formate produced oxalate. The latter reaction has been extensively studied for a long time and has already been commercialized. ...
Oxalic acid is an attractive chemical platform potentially available from CO2 due to its established applications and chemical characteristics enabling it to serve as a mediator in hydrometallurgy including iron-making. However, a method for synthesizing oxalic acid from CO2 has yet to be established. In the present work, the formation of oxalate scaffold during heating of cesium carbonate (Cs2CO3) in the presence of CO2 and H2 as reactants was experimentally investigated with a particular focus on the influence of supporting Cs2CO3 over porous materials. Among the support materials examined, activated carbon (AC) had a notable effect in improving the reaction rate and yield of total carboxylates (formate and oxalate) during experiments with an autoclave. An important problem was the dominant presence of formate, the intermediate between carbonate and oxalate, accounting for over 90% of the carboxylates. Changing the reaction conditions, including temperature, reaction time, partial pressure of gas components, and amount of loaded Cs2CO3, did not alter the situation. Alternatively, re-heating of the formate-rich salts over AC under CO and CO2 enhanced the oxalate fraction while maintaining the total carboxylates yield. Benefiting from the employment of support material, the two-step conversion was carried out using a gas-flow type reactor with a packed bed of Cs2CO3 supported over AC. In this reaction system, because water, acting as a promoter, was absent, the total carboxylates yield was lower than that in the autoclave, while the oxalate fraction was higher, being 71.8% with a yield of 43.2% on a Cs2CO3-carbon basis.
... As part of the concerted effort to find sustainable and biomassbased routes to industrially demanded chemicals, several strategies have been developed in recent years to explore such renewable pathways for the production of glycolic acid (GA). Currently, the α-hydroxycarboxylic acid GA, which is an important precursor for biodegradable polyester production, [1] is still produced either by carbonylation of formaldehyde [2] or by hydrolysis of monochloroacetic acid. [3] "Conventional" biomass-based processes rely on the growth, harvesting and subsequent conversion of plant biomass. ...
... For both GC and HPLC analysis external calibrations allowed quantification of all mentioned compounds. Based on this, GA conversion as well as yield and selectivity of the products were determined as follows in Equations (1), (2) and (3): Conversion of GA X GA; t ¼ 1 À n GA; t n GA; initial (1) Yield of product P Y P; t ¼ n P; t n GA; initial (2) Selectivity for product P S P; t ¼ Y P; t X GA; t ...
Ethylene glycol (EG) is obtained by a novel, two-step approach combining a biotechnological and a heterogeneously catalyzed step. First, microalgae are cultivated to photobiocatalytically yield glycolic acid (GA) by means of photosynthesis from CO2 and water. GA is continuously excreted into the surrounding medium. In the second step, the GA-containing algal medium is used as feedstock for catalytic reduction with H2 to EG over a Ru/C catalyst. The present study focuses on the conversion of an authentic algae-derived GA solution. After identification of the key characteristics of the algal medium (compared to pure aqueous GA), the influence of pH, numerous salt additives, pH buffers and other relevant organic molecules on the catalytic GA reduction was investigated. Nitrogen- and sulfur-containing organic molecules can strongly inhibit the reaction. Moreover, pH adjustment by acidification is required, for which H2 SO4 is found most suitable. In combination with a modification of the biotechnological process to mitigate the use of inhibitory compounds, and after acidifying the algal medium, over Ru/C a EG yield of up to 21 % even at non-optimized reaction conditions was achieved.
... Glycolic acid (GA) is the smallest α-hydroxycarboxylic acid and best known as a monomer for the production of biodegradable polymers, mainly poly(glycolic acid) and poly(lactic-co-glycolic acid). [1] To mitigate the dependence on fossil resources, several biomass-based concepts for a more sustainable production of GA have been reported. In that context, De Clercq et al. [2] as well as Dusselier et al. [3] review processes applying heterogeneous catalysis to obtain GA from biomass. ...
The production of industrially demanded polymer precursor ethylene glycol (EG) from biomass‐accessible aqueous glycolic acid (GA) was investigated in this study. The systematic investigation of different active metals as well as, for the first time, various support materials revealed Ru/TiO2 and Ru/ZrO2 to be the most active catalysts in the heterogeneously catalyzed reduction of GA with molecular H2. Catalytic activity is enhanced by facilitated reduction of the active Ru species due to metal‐support interactions. An assessment of several other catalyst properties (metal surface area, acid properties, porosity) revealed that high metal dispersion is also beneficial. Up to 94 % GA conversion and 95 % selectivity for EG were obtained under optimized and mild reaction conditions (105 °C, 60 bar H2 pressure, 23 h, Ru/TiO2 as catalyst). This shows that the heterogeneously catalyzed reduction of biomass‐derived aqueous GA solutions can be a promising alternative for the renewable production of EG.
... Therefore, as a world, we will need to transition from plastics produced from fossil resources to plastics produced from carbon already "above the ground". There are only two alternative feedstocks for producing virgin plastic materials: biomass and CO2 (via carbon capture and utilisation (CCU)) [5]. Next to sustainable feedstocks, other options to minimise the footprint of plastics are the well-known three R's: reduce, reuse and recycle. ...
The predicted growth in plastic demand and the targets for global CO2 emission reductions require a transition to replace fossil-based feedstock for polymers and a transition to close- loop recyclable, and in some cases to, biodegradable polymers. The global crisis in terms of plastic littering will furthermore force a transition towards materials that will not linger in nature but will degrade over time in case they inadvertently end up in nature. Efficient systems for studying polymer (bio)degradation are therefore required. In this research, the Respicond parallel respirometer was applied to polyester degradation studies. Two poly(lactic-co-glycolic acid) copolyesters (PLGA12/88 and PLGA6/94) were tested and shown to mineralise faster than cellulose over 53 days at 25 °C in soil: 37% biodegradation for PLGA12/88, 53% for PLGA6/94, and 30% for cellulose. The corresponding monomers mineralised much faster than the polymers. The methodology presented in this article makes (bio)degradability studies as part of a materials development process economical and, at the same time, time-efficient and of high scientific quality. Additionally, PLGA12/88 and PLGA6/94 were shown to non-enzymatically hydrolyse in water at similar rates, which is relevant for both soil and marine (bio)degradability.
... [15,16] CO 2 -based chemicals such as oxalic acid will become new platform chemicals for a wide range of downstream products such as mono-ethylene glycol (MEG) as well as glycolic and glyoxylic acid that all can be obtained from oxalic acid. [20] Once formate is made from CO 2 , a high-performing process for the coupling of formate to oxalate will bridge the gap between CO 2 reduction and the large-scale utilization of this CO 2 -derived carbon in new chemical products with negative CO 2 footprints. This work is part of the European Horizon 2020 project "OCEAN" in which we develop a continuous process from CO 2 to polymers. ...
An interesting contribution to solving the climate crisis involves the use of CO2 as a feedstock for monomers to produce sustainable plastics. In the European Horizon 2020 project “OCEAN” a continuous multistep process from CO2 to oxalic acid and derivatives is developed, starting with the electrochemical reduction of CO2 to potassium formate. The subsequent formate‐to‐oxalate coupling is a reaction that has been studied and commercially used for over 150 years. With the introduction of superbases as catalysts under moisture‐free conditions unprecedented improvements were shown for the formate coupling reaction. With isotopic labelling experiments the presence of carbonite as an intermediate was proven during the reaction, and with a unique operando set‐up the kinetics were studied. Ultimately, the required reaction temperature could be dropped from 400 to below 200 °C, and the reaction time could be reduced from 10 to 1 min whilst achieving 99 % oxalate yield.
... 9,10 Additionally, electrochemical routes towards both methanol and glycolic acid also exist via the electrocatalytic reduction of CO 2 into formate. 11 A new process from syngas to PGA was recently developed by Pujing Chemical Industry Limited Co. Ltd (PJCHEM), China. The chemical process is shown in Fig. 2 In this process, firstly, syngas is purified and separated into CO and H 2 . ...
The concerns about the accumulating plastic waste pollution have stimulated the rapid development of bioplastics, in particular biodegradable bioplastics derived from renewable resources. Driven by a low carbon circular economy,...
Here, we show that the presence of potassium ions in the catholyte modulates the selectivity of the Pb plate electrode, leading to the formation of tartrate, a C 4 compound, from...
Herein, we show that unmodified titanium electrodes bearing the naturally-forming native TixOy coating display superior activity for the electroreduction of oxalic acid to glyoxylic acid and glycolic acid compared to...
