EDP Sciences logo
Submit your paper
Search
Menu
Home All issues Volume 77 (2022) Sci. Tech. Energ. Transition, 77 (2022) 1 Full HTML
Open Access
Issue
Sci. Tech. Energ. Transition
Volume 77, 2022
Article Number 1
Number of page(s) 5
DOI https://doi.org/10.2516/stet/2021001
Published online 28 January 2022

© The Author(s), published by EDP Sciences, 2022

Licence Creative CommonsThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1 Introduction

The increase in emissions of carbon dioxide (CO2) into the atmosphere, due to the consumption of fossil fuels (coal, gas and oil), is the main cause of climate change. Because CO2 is a greenhouse gas, it blocks heat from the planet. Its high concentrations in the atmosphere, reaching a level above 415 parts per million in 2019 [1] (historical record) have led to an increase in global temperature with devastating effects on the environment and human well-being (Fig. 1).

thumbnail Fig. 1

Main effects of CO2 emissions.

Although the CO2 can be eliminated by natural processes, the current rate of CO2 emissions exceeds that of natural elimination. This has led to growing public dissatisfaction, putting pressure on governments around the world to take action to reduce emissions from CO2 and exploit its abundance in the atmosphere.

The top priority is therefore to avoid CO2 emissions, mainly by developing renewable energies, also reducing energy consumption and improving energy efficiency. At the same time, energy companies are also working on Carbon Capture and Storage (CCS) which is a major strategy that can be used to reduce CO2 emission. There are three methods for CCS: pre-combustion capture, oxy-fuel process, and post-combustion capture. Among them, post-combustion capture is the most important one because it offers flexibility and it can be easily added to the operational units [2–4]. Beside the geological storage, the CO2 mineralization or the algae feeding are two complementary technologies to “sequester” CO2 [5].

Beyond these interesting approaches that tackle with the stakes with the stakes of reduction CO2 emissions, there is also another approach, which interestingly sees CO2 as a new chemical building block. Hence, even if chemistry accounts only for 10% of oil and gas consumption, thus same percentage of CO2 emission, there is still interest to reduce environmental impacts of chemistry through the use of renewable resources, to follow the principles of Green Chemistry. Hence, considering CO2 as a raw material, known as Carbon Capture and Use (CCU), notably, as a basic brick in the production of polymers, may have also interest to follow the principles of Green Chemistry. Hence, CO2 could be a renewable and inexhaustible platform chemical, produced locally from multiple sources and find utility for the synthesis of commodities (methanol, urea, (in)organic carbonates, formic acid), fuel (methane, alcanes) and particularly polymers. The polymers annual production is around 400 million tonnes compared to the global CO2 emission (nearly 40 Gt/y), the utilization of CO2 a raw material to fabricate polymers will only show marginal effect on the anthropologic CO2 emissions and climate change but it could draw the reuse of CO2 and improves the circularity of polymer economy [6, 7].

2 Different approaches for the use of CO2

Until now, the production of polymers has been mainly based on petrochemical raw materials, i.e. mainly oil. However, we dispose of finite fossil resources while CO2 is inexhaustible. In addition, converting oil into precursor chemicals also consumes energy, resulting in further CO2 emissions, even if industries has developed improved energy efficacity for last decades. Moreover, the chemical industry has already made a lot of progress in implementing CO2 as a new raw material [8–17].

The use of CO2 for the manufacture of plastic is beneficial to the environment in two ways: First, the CO2 is directly incorporated into the polymers and partially replaces oil as a raw material. In order to compare efficacy of the whole process from cradle to gate (raw material), a Life Cycle Assessment would be required. Recently, some companies have studied such analyses to improve their processes either conventional or new [18].

There are two chemical approaches to incorporating CO2 into the development of polymer materials (Fig. 2): either directly using it as a polymer construction block, or indirectly through the involvement of CO2-based monomers to form other polymers. Both approaches are proven possible and feasible to a certain extent [19–27].

thumbnail Fig. 2

Approaches for CO2 conversion into chemicals/polymers.

2.1 The direct approach

Chemical fixation of CO2 is very interesting from a carbon use perspective, as CO2 is a low-cost, non-toxic, carbon-rich resource that can be used to produce value-added chemicals and materials. The most promising area of use of CO2 is the co-polymerization of CO2 and epoxide monomers to obtain Polycarbonates (PCs), which has been pioneered by Inoue et al. in 1969 [28]. These polymers not only have excellent barrier properties to oxygen and water, but they also have excellent biocompatibility and biodegradability. Given their exceptional properties, PCs can be used as non-polluting materials for the production of disposable medical products, in addition to food packaging, adhesives and composite materials, etc. (Fig. 3)

thumbnail Fig. 3

Examples of applications of polycarbonates.

However, it is necessary to mention that the thermodynamic stability of the CO2, limits its use as a reagent. Hence the value of using energy-rich reagents such as epoxides in the presence of suitable catalysts (Fig. 4) [29–38].

thumbnail Fig. 4

Catalyzed copolymerization of CO2 and epoxides yielding polycarbonates.

Indeed, since the pioneering work of Inoue et al. who prepared Polypropylene Carbonate (PPC) from the CO2 and Propylene Oxide (PO), using a heterogeneous catalytic water/diethylzinc system, the copolymerization of epoxides and CO2 has been widely developed. In general, the catalysts used for copolymerization of CO2 and epoxides are components based on transition metals or metals from the main group of elements that are abundant on earth, such as Zn, Co, Cr, Mg, Al, which are either insoluble or soluble in the reaction system during copolymerization.

The most accomplished CO2/epoxide copolymerization systems are based on the Transition Metal Complexes Cr (III), Co (III) or Zn (II) with Schiff base ligands. In the case of CO2 copolymerization and Propylene Oxide (PO), Polypropylene Carbonate (PPC) with a molar mass of up to 300,000 g mol−1 can be prepared using a recyclable catalyst ((salen)Co(III)) [39].

2.1.1 Catalysts

Depending on the type of catalyst, the reaction can be directed to produce a specific type of polymer. A wide range of metal complexes (Zn, Cr, Co, Al, Fe) with the general formula “LnMX” (Ln is a suitable, often multidentate ligand; X is typically a halide or other suitable initiating group; M is typically a di- or trivalent metal cation) have been designed to promote the ROCOP of CO2 with epoxides (Fig. 5) [40, 41].

thumbnail Fig. 5

Initiation of General coordination–insertion mechanism for the synthesis of PCs by ROCOP of CO2 and epoxides.

These catalysts can be roughly divided into two categories:

  • The homogeneous catalysts, represented by cobalt and chromium with salen ligands.

  • The heterogeneous catalysts represented by zinc glutarate and Double Metal Cyanides (DMCs).

Homogeneous catalysts are more active and selective compared to heterogeneous ones, and are more suitable for research because their chemical structures are well defined. However, these first ones require a multi-step synthesis due to the complexity of the ligands (Fig. 6). However, regardless of the catalysts used in copolymerization, the polycarbonates produced are contaminated with metals, making them toxic and coloring during degradation. A disposal step after polymerization is therefore necessary to ensure a wide applicability, especially when it comes to products dedicated to electronic processing or in packaging.

thumbnail Fig. 6

Different kinds of catalysts.

Recently, great importance has been placed on processes that are environmentally friendly. This has resulted in the use of catalysts based on metal complexes of the main group.

Indeed, with catalysts such as Co(III) and Cr(III) that are effective, traces of metal residues are obtained inside the resin that can lead to problems of toxic and coloured degradation, which limits their fields of applicability. These affect their performance and therefore limit their applications. However, this is not the case for aluminum, one of the first metals studied as a catalyst since the discovery of CO2 copolymerization and epoxides. Aluminum is becoming abundant on land, cheap and biocompatible. Aluminum complexes are also known to catalyze a wide range of other polymerization reactions, which would allow the development of CO2-based sequential copolymers other than epoxides. However, due to the competitive homopolymerization of aluminum-catalyzed epoxides, more work will be needed to improve its catalytic effects [42].

2.2 The indirect approach

The CO2 can also be used to produce chemical components for polymer synthesis, particularly urea. Urea is widely used in the fertilizer industries as a rich source of nitrogen. Urea is non-toxic and is a raw material for the production of many important chemical compounds such as various plastics, resins and adhesives. Nowadays, approximately 200 Mt/y of urea is produced in the world. To produce this amount of urea, 150 Mt/y of CO2 is required. The most common method for production of urea is reforming natural gas, producing both carbon dioxide and ammonia. Carbon dioxide can also be produced from combustion. Hence, considering, CO2, nitrogen, and water as the main products of the combustion process, capturing of CO2 and removing water from the combustion gas can lead to a high purity N2. This N2 could react with hydrogen to yield ammonia. Therefore, the production of urea by reaction of ammonia with CO2, captured from combustion flue gases, would increase the economic justification of CO2 capture unit [43].

This opens up the possibility of obtaining a range of thermosetting polymers, such as Urea-Formaldehyde (UF) resins and Melamine-Formaldehyde (MF), as well as industrial plastics, such as Polyoxymethylene (POM) or Polymethylmethacrylate (PMMA). In the first case, UF resin can be obtained from urea, which is directly produced by the CO2’s reaction with Ammoniac, and Formaldehyde, which is obtained from methanol derived from the CO2; similarly, the ingredients of MF resins are Melamine, obtained from urea, and Formaldehyde. For the examples provided last, the POM can be produced from the CO2 via formic acid, and PMMA from methyl Acrylate obtained from methanol derived from CO2 [44].

3 Properties of polycarbonates synthesized from CO2

Despite interesting properties, polycarbonates from catalyzed CO2 reactions and epoxides exhibit a non-variable structure, linked to alternation of CO2 and epoxide units, which limits their properties. Moreover, the absence of aromatic ring, compare to conventional polycarbonates, reduces their thermo-mechanical properties.

Hence, the limited properties of these PCs can be extended by combining them with biopolymers, such as starch, or synthetic polymers, such as PMMA, where CO2-based PCs confer biodegradability or act as an important additive. In addition, these polycarbonates can also be treated using traditional processing techniques, such as injection molding or molten extrusion. This makes it possible to produce on an industrial scale. PCs from Bisphenol A-based CO2 can also be synthesized to produce superior traditional polycarbonates, via greener pathways without toxic phosgene. Additionally, high Tg CO2-based polycarbonates have been reported by Kindermann et al. who succeeded in the copolymerization of CO2 and limonene oxide to obtain polycarbonates with unprecedented high glass transition of up to 180 °C [45]. However, currently, PCs produced by conversion of CO2 are mainly end functionalized with hydroxyl groups and used as poly(carbonate-ether) polyols, for the synthesis of Polyurethane (PU) with diisocyanates [46].

4 Conclusion

In conclusion, it is important to note that while this area of research is hardly new, the use of CO2 as a raw material remains one of the most interesting and visionary technologies. With limited fossil resources, the use of CO2 as a chemical raw material is a promising approach to global carbon management. In this sense, the use of CO2 to produce polymers has an obvious ecological advantage over conventional polymers. It is even possible to improve this situation by following the different approaches of direct and indirect use. The present review was focused on CO2-based materials that could be manufactured from precursors already produced in large scale (such as urea) or that are reaching the industrial scale (PC). Pioneering examples already show that the chemical use of CO2 for the production of polymers on an industrial scale is possible. Hence, the use of CO2 as an alternative raw material in the chemical industry is still in its infancy. Future efforts will aim to demonstrate the potential of this gas and initiate a possible change of image, from a greenhouse gas harmful to the environment to a new useful and sustainable raw material.

References

  • IEA (2020) Global CO2 emissions in 2019, IEA, Paris. https://www.iea.org/articles/global-co2-emissions-in-2019. [Google Scholar]
  • Bui M., Adjiman C.S., Bardow A., Anthony E.J., Boston A., Brown S., Fennell P.S., Fuss S., Galindo A., Hackett L.A., Hallett J.P., Herzog H.J., Jackson G., Kemper J., Krevor S., Maitland G.C., Matuszewski M., Metcalfe I.S., Petit C., Puxty G., Reimer J., Reiner D.M., Rubin E.S., Scott S.A., Shah N., Smit B., Trusler J.P.M., Webley P., Wilcox J., Mac Dowell N. (2018) Carbon Capture and Storage (CCS): the way forward, Energy Environ. Sci. 11, 5, 1062–1176. [CrossRef] [Google Scholar]
  • Cuéllar-Franca R.M., Azapagic A. (2015) Carbon capture, storage and utilisation technologies: a critical analysis and comparison of their life cycle environmental impacts, J. CO2 Util. 9, 82–102. [Google Scholar]
  • Feron P.H.M., Hendriks C.A. (2005) CO2 capture process principles and costs, Oil Gas Sci. Technol. 60, 451–459. [CrossRef] [Google Scholar]
  • Sanna A., Uibu M., Caramanna G., Kuusik R., Maroto-Valer M.M. (2014) A review of mineral carbonation technologies to sequester CO2, Chem. Soc. Rev. 43, 8049. [CrossRef] [PubMed] [Google Scholar]
  • Olajire A. (2013) Valorization of greenhouse carbon dioxide emissions into value-added products by catalytic processes, J. CO2 Util. 3–4, 74–92. [Google Scholar]
  • Nova Institute (2015) Bio-based & CO2-based economy, http://nova-institute.eu. [Google Scholar]
  • Babu R.P., O’Connor K., Seeram R. (2013) Current progress on bio-based polymers and their future trends, Prog. Biomater. 2, 8. [CrossRef] [Google Scholar]
  • Schmid G., Arvanitis E., Baldauf M., Taroata D., Walachowicz F. (2013) A method and a system for converting carbon dioxide into chemical starting materials. US2013178677A1. [Google Scholar]
  • Connolly H.P. (2011) Preparation of halogenated hydrocarbons. CA2751148A1. [Google Scholar]
  • Bhethanabotla V., Daza Y., Dutta D., Kuhn J.N. (2017) Systems and methods for converting carbon dioxide into chemical feedstock. US9815702B1. [Google Scholar]
  • Piispanen A (2017) Procédé et appareil pour séparer le dioxyde de carbone et pour utiliser le dioxyde de carbone. WO2017140954A1. [Google Scholar]
  • Bogild Hansen J., Friis Pedersen C., Schjodt N.C. (2014) Process for the production of chemical compounds from carbon dioxide. AU2013256880A1. [Google Scholar]
  • Lambert S., Wagner M. (2017) Environmental performance of bio-based and biodegradable plastics: the road ahead, Chem. Soc. Rev. 46, 6855–6871. [CrossRef] [PubMed] [Google Scholar]
  • Sun Z., Fridrich B., de Santi A., Elangovan S., Barta K. (2018) Bright side of lignin depolymerization: toward new platform chemicals, Chem. Rev. 118, 614–678. [CrossRef] [PubMed] [Google Scholar]
  • Iwata T. (2015) Biodegradable and bio-based polymers: future prospects of eco-friendly plastics, Angew. Chem. Int. Ed. 54, 3210–3215. [CrossRef] [Google Scholar]
  • Castro-Aguirre E., Iniguez-Franco F., Samsudin H., Fang X., Auras R. (2016) Poly(lactic acid) – mass production, processing, industrial applications, and end of life, Adv. Drug Delivery Rev. 107, 333–366. [CrossRef] [Google Scholar]
  • Sternberg A., Jens C.M., Bardow A. (2017) Life cycle assessment of CO2-based C1-chemicals, Green Chem. 19, 2244. [CrossRef] [Google Scholar]
  • Grignard B., Gennen S., Jérôme C., Kleij A.W., Detrembleur C. (2019) Advances in the use of CO2 as a renewable feedstock for the synthesis of polymers, Chemical Society Reviews. [Google Scholar]
  • Li Y., Zhang Y.-Y., Hu L.-F., Zhang X.-H., Du B.-Y., Xu J.-T. (2018) Carbon dioxide-based copolymers with various architectures, Prog. Polym. Sci. 82, 120–157. [CrossRef] [Google Scholar]
  • Muthuraj R., Mekonnen T. (2018) Recent progress in carbon dioxide (CO2) as feedstock for sustainable materials development: Co-polymers and polymer blends, Polymer 145, 348–373. [CrossRef] [Google Scholar]
  • Kamphuis A.J., Picchioni F., Pescarmona P.P. (2019) CO2-fixation into cyclic and polymeric carbonates: principles and applications, Green Chem. 21, 406–448. [CrossRef] [Google Scholar]
  • Yadav N., Seidi F., Crespy D., D’Elia V. (2019) Polymers based on cyclic carbonates as Trait d’Union between polymer chemistry and sustainable CO2 utilization, ChemSusChem 12, 724–754. [CrossRef] [PubMed] [Google Scholar]
  • Xu Y., Lin L., Xiao M., Wang S., Smith A.T., Sun L., Meng Y. (2018) Synthesis and properties of CO2-based plastics: environmentally-friendly, energy-saving and biomedical polymeric materials, Prog. Polym. Sci. 80, 163–182. [CrossRef] [Google Scholar]
  • Liu S., Wang X. (2017) Polymers from carbon dioxide: polycarbonates, polyurethanes, Curr. Opin. Green Sustainable Chem. 3, 61–66. [CrossRef] [Google Scholar]
  • Zhu Y., Romain C., Williams C.K. (2016) Sustainable polymers from renewable resources, Nature 540, 354. [CrossRef] [PubMed] [Google Scholar]
  • Poland S.J., Darensbourg D.J. (2017) A quest for polycarbonates provided via sustainable epoxide/CO2 copolymerization processes, Green Chem. 19, 4990–5011. [CrossRef] [Google Scholar]
  • Inoue S., Koinuma H., Tsuruta T. (1969) Copolymerization of carbon dioxide and epoxide with organometallic compounds, Die Makromol. Chem. 130, 210–220. [CrossRef] [Google Scholar]
  • Aresta M. (ed) (2010) Carbon dioxide as chemical feedstock, Wiley-VCH Verlag GmbH & Co. KGaA. [CrossRef] [Google Scholar]
  • Aresta M., Dibenedetto A., Angelini A. (2014) Catalysis for the valorization of exhaust carbon: from CO2 to chemicals, materials, and fuels. Technological use of CO2, Chem. Rev. 114, 1709–1742. [CrossRef] [PubMed] [Google Scholar]
  • Sakakura T., Choi J.-C., Yasuda H. (2007) Transformation of carbon dioxide, Chem. Rev. 107, 2365–2387. [CrossRef] [PubMed] [Google Scholar]
  • Omae I. (2012) Recent developments in carbon dioxide utilization for the production of organic chemicals, Coord. Chem. Rev. 256, 1384–1405. [CrossRef] [Google Scholar]
  • Dabral S., Schaub T. (2019) The use of Carbon Dioxide (CO2) as a building block in organic synthesis from an industrial perspective, Adv. Synth. Catal. 361, 223–246. [CrossRef] [Google Scholar]
  • Peters M., Kohler B., Kuckshinrichs W., Leitner W., Markewitz P., Muller T.E. (2011) Chemical technologies for exploiting and recycling carbon dioxide into the value chain, ChemSusChem 4, 1216–1240. [CrossRef] [PubMed] [Google Scholar]
  • Maeda C., Miyazaki Y., Ema T. (2014) Recent progress in catalytic conversions of carbon dioxide, Catal. Sci. Technol. 4, 1482–1497. [CrossRef] [Google Scholar]
  • Schlager S., Fuchsbauer A., Haberbauer M., Neugebauer H., Sariciftci N.S. (2017) Carbon dioxide conversion to synthetic fuels using biocatalytic electrodes, J. Mater. Chem. A 5, 2429–2443. [CrossRef] [Google Scholar]
  • Liu Q., Wu L., Jackstell R., Beller M. (2015) Using carbon dioxide as a building block in organic synthesis, Nat. Commun. 6, 5933. [CrossRef] [Google Scholar]
  • Riduan S.N., Zhang Y. (2010) Recent developments in carbon dioxide utilization under mild conditions, Dalton Trans. 39, 3347–3357. [CrossRef] [PubMed] [Google Scholar]
  • Sujith S., Min J.K., Seong J.E., Na S.J., Lee B.Y. (2008) A highly active and recyclable catalytic system for CO2/propylene oxide copolymerization, Angew Chem Int Ed Engl. 47, 38, 7306–7309. [CrossRef] [Google Scholar]
  • Rokicki G., Kowalczyk T. (2000) Synthesis of oligocarbonate diols and their characterization by MALDI-TOF spectrometry, Polymer 41, 9013–9031. [CrossRef] [Google Scholar]
  • Pawlowski P., Rokicki G. (2004) Synthesis of oligocarbonate diols from ethylene carbonate and aliphatic diols catalyzed by alkali metal salts, Polymer 45, 3125–3137. [CrossRef] [Google Scholar]
  • Huang J., Worch J.C., Dove A.P., Coulembier O. (2020) Update and challenges in carbon dioxide‐based polycarbonate synthesis, ChemSusChem 13, 469–487. [CrossRef] [PubMed] [Google Scholar]
  • Koohestanian E., Sadeghi J., Mohebbi-Kalhori D., Shahraki F., Samimi A. (2018) A novel process for CO2 capture from the flue gases to produce urea and ammonia, Energy 144, 279–285. [CrossRef] [Google Scholar]
  • Alper E., Yuksel Orhan O. (2017) CO2 utilization: Developments in conversion processes, Petroleum 3, 1, 109–126. [CrossRef] [Google Scholar]
  • Kindermann N., Cristofol A., Kleij A.W. (2017) Access to biorenewable polycarbonates with unusual glass-transition temperature (Tg) modulation, ACS Catal. 7, 3860–3863. [CrossRef] [Google Scholar]
  • Muthuraj R., Mekonnen T. (2018) Recent progress in carbon dioxide (CO2) as feedstock for sustainable materials development: Co-polymers and polymer blends, Polymer 145, 348–373. [CrossRef] [Google Scholar]

All Figures

thumbnail Fig. 1

Main effects of CO2 emissions.
In the text
thumbnail Fig. 2

Approaches for CO2 conversion into chemicals/polymers.
In the text
thumbnail Fig. 3

Examples of applications of polycarbonates.
In the text
thumbnail Fig. 4

Catalyzed copolymerization of CO2 and epoxides yielding polycarbonates.
In the text
thumbnail Fig. 5

Initiation of General coordination–insertion mechanism for the synthesis of PCs by ROCOP of CO2 and epoxides.
In the text
thumbnail Fig. 6

Different kinds of catalysts.
In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.