Chemical Value Chain Research Articles

Polyethylene Recycling Via Water Activation By Ball Milling

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon‐carbon (C–C) bonds.[1] High temperature and noble metals are usually required for depolymerization.[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter‐chain alkanes, alkenes, alcohols, and ketones (Cn, where n ≲ 50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re‐entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth‐abundant Al₂O₃ was milled with reactants.

Polyethylene Recycling via Water Activation by Ball Milling.

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon-carbon (C-C) bonds.[1] High temperature and noble metals are usually required for depolymerization.[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter-chain alkanes, alkenes, alcohols, and ketones (Cn, where n≲50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re-entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth-abundant Al2O3 was milled with reactants.

How Mechanical Challenges Affect the Performance of Industrial Scale Carbon Dioxide Electrolyzer Cells?

One of the most important challenge of humanity in the mid-21st century is to maintain economic growth in an environmentally sustainable way. The European Green Deal addresses this issue, and it aims at making Europe climate neutral by 2050. To reach this aim, a promising technology is to convert a greenhouse gas, carbon dioxide into valuable chemicals (produce e.g., energy carriers, fine chemicals, pharmaceuticals) in an environmentally and economically sustainable manner, such as the utilization of renewable energy sources.The direct electrochemical reduction of carbon dioxide into carbon-monoxide (a high-value product which can be readily used in the chemical value chain) is a promising waste-to-wealth approach among the developed technologies and it can be easily coupled with carbon-free electricity sources to make the process completely sustainable. Novel catalysts, electrode assemblies, and cell configurations are all necessary to achieve economically appealing performance, as well as finding technological solutions that enable scale-up to reach industrially relevant dimensions.Zero-gap electrolyzer cell technology operates with high reaction rates and good efficiencies under ambient and near ambient conditions. In addition, its operation is simpler compared to other types of carbon-dioxide electrolyzer cell technologies (just one example: there is no need very precisely pressure control because no flowing catholyte inside the cell), and this allows the scale up of such architectures. Exploring the fundamentals and understanding of the chemistry in zero-gap electrochemical cells is carried out by many research groups, usually with small experimental test cells. These results provide a good scientific basis (e.g., to select the right catalysts, components, or to study long-term degradation, etc.), however, compared to the size of an industrial-scale electrolyzer, these experimental cells only measure a "one point" chemistry. The results cannot be transferred without careful consideration during scale-up, due to several additional challenges. These challenges are mainly of mechanical origin, and all of these create uneven conditions that can significantly affect the chemistry of the on given sections of the cells.Over the past several years, we have gone through the steps of scaling up electrochemical cells (for CO2-to-CO conversion) from a small experimental test cell (8 cm2) to an industrial-sized cell stack (2500 cm2 / cell). During the development journey we encountered many of the challenges outlined above. In this talk, I am going to present some of these challenges, their origins, what affects them and by them, and what principles can be used to find solutions.

Technology Readiness and Emerging Prospects of Coupled Catalytic Reactions for Sustainable Chemical Value Chains.

Transitioning from both the direct and indirect use of fossil fuels to the renewable and sustainable resources of the near future demands a focal shift in catalysis research - from investigating catalytic reactions in isolation to developing coupled reactions for modern chemical value chains. In this Perspective, we discuss the status and emerging prospects of coupled catalytic reactions across various scales and provide key examples. Besides being a sustainable and essential alternative to current fossil-based processes, the coupling of catalytic reactions offers novel and scalable pathways to value-added chemicals. By emphasizing the specific requirements and challenges arising from coupled reactions, we aim to identify and underscore research needs that are critical to expedite their development and to fully unlock their potential for chemical and fuel production.

The profitability-sustainability trade-off in complex chemical value chains

The profitability-sustainability trade-off in complex chemical value chains

Csp2–H functionalization of phenols: an effective access route to valuable materials via Csp2–C bond formation

Simple phenols are crucial in the chemical value chain. Efforts aim to enhance their molecular complexity, with direct functionalization of Csp2–H as a key technique, facilitating economical and atomic construction of new Csp2–C bonds.

Biomass-derived 6-hydroxy-6-hydroxymethyl-2H-pyran-3(6H)-one: Green synthesis and antibacterial potential

“Defossilization” of the chemical value chain is increasingly competitive in tomorrow’s sector. Herein, a green synthesis of 6-hydroxy-6-hydroxymethyl-2H-pyran-3(6H)-one with high yield (98.1%) from bio-based feedstock 2,5-bis(hydroxymethyl)furan and evaluation for the antibacterial behavior against both Gram-positive (S. aureus, B. subtilis) and Gram-negative (E. coli, P. aeruginosa) bacteria are reported. With the concentration of 20 mg/mL, the pyrone molecular is extremely sensitive for the four selected germs determined by inhibition zone qualitative assay, and the minimum inhibitory concentration (MIC) is 0.3125 mg/mL towards all. Taking advantages of good degradability and potential broad-spectrum antibacterial activities, biomass-derived pyrones are expected to drive the development of the alternative in terms of both functionality and sustainability.

Adaptive Catalytic Systems for Chemical Energy Conversion.

The rapidly growing importance of green hydrogen and renewable carbon resources as essential feedstocks for sustainable chemical value chains opens room for disruptive innovations regarding chemical production processes. The fluctuation and variability associated with non-fossil energy and raw material supply holds many challenges for catalysts to cope with the resulting dynamics. However, many new opportunities also arise once catalyst design starts to aim at performance that is "adaptive" rather than "task-specific". In this Scientific Perspective, we propose to define adaptivity in catalysis on the basis of three essential properties that are reversibility, rapidity, and robustness (R3 rule). Promising design strategies and selected examples are described to substantiate the scientific concept and to highlight its potential for chemical energy conversion.

Beyond Plastics-to-Plastics to Waste-to-Products: Opportunities for Closing the Carbon Cycle via Chemical Recycling

AbstractThe plastic crisis is a key driver for chemical recycling (CR), with focus placed on plastics circularity via Plastics‐to‐Plastics. This neglects its potential in enabling circularity for a wide range of carbon‐containing waste and hinders a critical discussion of its broader contributions to decarbonizing the chemical sector. To address this gap, four CR routes and their integration in the conventional waste treatment and chemical production value chains are briefly reviewed, and reasons proposed for a focus expansion to Waste‐to‐Products to realize opportunities for closing the carbon cycle via chemical recycling.

China’s Evolving Role in the Chemical Global Value Chain

This paper explores China’s integration into the chemical global value chain (GVC) in the past decade through the experience of foreign chemical companies. It examines how the intellectual monopoly of foreign companies help them to exercise control in the GVC, but over time how the challenges of co-evolving with local rival Chinese companies erode that advantage as they face the challenge of maintaining market share by learning to collaborate within a very different innovation environment. It explores these developments by contextualizing the presence of Chinese companies within particular segments of the GVC and through a longitudinal series of company interviews.

Pd(II)-catalyzed carboxylation of aromatic C─H bonds with CO2.

The carboxylation of nonactivated C─H bonds provides an attractive yet hitherto largely elusive chemical process to synthesize carboxylic acids by incorporation of CO2 into the chemical value chain. Here, we report on the realization of such a reaction using simple and nonactivated arenes as starting materials. A computationally designed Pd(II) complex acts as organometallic single-component catalyst, and apart from a base, necessary for thermodynamic stabilization of the intermediates, no other additives or coreagents are required. Turnover numbers up to 102 and high regioselectivities are achieved. The potential of this catalytic reaction for "green chemistry" is demonstrated by the synthesis of veratric acid, an intermediate for pharmaceutical production, from CO2 and veratrol.

NaWuReT and YounGeCatS Joint Summer School – Shaping a Green Future by Reaction Engineering and Catalysis

AbstractSustainability has become one of the greatest scientific challenges of our time. Redesigning the chemical value chain with sustainable reactions and non‐fossil feedstocks, closing cycles in energy storage and digitalization demand interdisciplinary scientific excellence. The summer school organized by the early career researchers groups of Germanys reaction engineering and catalysis community aimed to bring together young scientists from reaction engineering and catalysis with experts from industry and academia to work on sustainable chemistry, energy storage and digitalization. During three days of lectures, workshops and intensive group work, the hot topics of our time were discussed and seminal ideas to tackle current challenges were formed.

A Tailored Life Cycle Assessment Database to Reduce Environmental Impacts of the Chemical Value Chain in Japan – cm.chemicals

A Tailored Life Cycle Assessment Database to Reduce Environmental Impacts of the Chemical Value Chain in Japan – cm.chemicals

Modular and intensified — Reimagining manufacturing at the energy-chemistry nexus and beyond

Today's manufacturing is based on ample fossil fuel sources, large and centralized plants, and high waste intensity. Climate change, aging infrastructure, dwindling resources, increasing population, changing geopolitical landscape, and the COVID-19 pandemic have laid bare the frailties of the current global supply chain. While there is still place for centralized production, geographic variation in renewable energy sources and sustainable feedstocks calls for a flexible approach towards smaller-scale and more decentralized production. With the pressing need for decarbonization of power generation and the chemical value chain, flexible manufacturing will play a major role in redefining the energy-chemistry nexus. Intensification and modularization are identified as the key enablers for such a transition. A sample case study based on valorization of hydrogen sulfide extracted from sour gas is presented to demonstrate the potential economic favorability of modular chemical process intensification. Our work shows that a net profit of US$97 million can be achieved over a five-year operational period when compared to a conventional process. A complementary evaluation of green solvents is also provided to further improve the sustainability of the proposed solution.

Assessment of site-specific greenhouse gas emissions of chemical producers: Case studies of propylene and toluene diisocyanate

The chemical industry accounts for 20% of global industrial greenhouse gas (GHG) emissions and the plastics production is increasing worldwide by approx. 4% annually. To reduce GHG emissions and increase GHG transparency in chemical value chains despite industrial secrets, we developed an approach to estimate the product carbon footprint of chemicals site-specifically without using classified production data. The new approach, is applied to two comparative case studies: propylene and toluene diisocyanate (TDI) production in Germany. The case study analyses 23 crackers on 17 production sites and four TDI production sites in Germany. The results indicate significant GHG emissions variations between productions sites (Cradle-to-Gate) that could not be quantified before. Among the production sites, product-specific GHG emissions range between 0.95 and 1.51 kgCO2e/kg propylene (reduction potential of GHG emissions of 37.1%) and between 3.17 and 3.62 kgCO2e/kg TDI (reduction potential of GHG emissions of 12.4%). This indicates massive differences in GHG efficiency in the production of propylene and TDI and an immense GHG emission reduction potential in the manufacture of plastic-intensive products (e.g. in the automotive sector) by increased transparency and informed supplier selection and procurement decision making. The method is transferable to chemical sites worldwide and indicates an even higher GHG reduction potential worldwide.

Regioselective Synthesis of Polyfunctional Arenes by a 4-Component Catellani Reaction

Summary Polyfunctional arenes are an important part of the chemical value chain. To improve the efficiency of their synthesis, we have investigated a multicomponent approach built upon the Catellani platform. Here, we describe a 4-component coupling of aryl iodides lacking an ortho substituent that installs 3 discrete functional groups on the arene in a single step. The process is regio- and chemoselective and uncovers remote substituent effects that have a pronounced influence over intermediate Pd-(II) complexes. These intermediates have been a long-standing focus of the Catellani-reaction development, but persistent challenges have given rise to the well-known “ortho effect.” We now show that the ortho effect can be a positive element of reaction design, and that previously problematic iodides can now be used in complexity-generating transformations. In expanding the scope of the Catellani platform, we hope to provide mechanistic considerations to guide future reaction design, while also improving the environmental footprint of synthesizing polyfunctional arenes.

Research Progress Regarding Transition Metal-Catalyzed Carbonylations with CO<sub>2</sub>/H<sub>2</sub>

Ever-increasing energy demands due to rapid industrialization and urban population growth have drastically reduced petroleum reserves and increased greenhouse-gas production, and the latter has consequently contributed to climate change and environmental damage. Therefore, it highly desirable to produce fuels and chemicals from non-petroleum feedstocks and to reduce the atmospheric concentrations of greenhouse gases. One solution has involved using carbon dioxide (CO2), a main greenhouse gas, as a C1 feedstock for producing industrial fuels and chemicals. However, this requires high energy input from reductants or reactants with relatively high free energy (e.g., H-2 gas) because CO2 is a highly oxidized, thermodynamically stable form of carbon. H-2 can be generated through water photolysis, making it an ideal reductant for hydrogenating CO2 to CO. In situ generation of CO such as this has been developed for various carbonylation reactions that produce high value-added chemicals and avoid deriving CO from fossil fuels. This is beneficial because CO is toxic, and when extracted from fossil fuels it requires tedious separation and transportation. This combination of CO2 and H-2 allows for functional molecules to be synthesized as entries into the chemical industry value chain and would generate a carbon footprint much lower than that of conventional petrochemical pathways. Based on this, CO2/H-2 carbonylations using homogeneous transition metal-based catalysts have attracted increasing attention. Through this process, alkenes have been converted to alcohols, carboxylic acids, amines, and aldehydes. Heterogeneous catalysis has also provided an innovative approach for the carbonylation of alkenes with CO2/H-2. Based on these alkene carbonylations, the scope of CO2/H-2 carbonylations has been expanded to include aryl halides, methanol, and methanol derivatives, which give the corresponding aryl aldehyde, acetic acid, and ethanol products. These carbonylations revealed indirect CO2-HCOOH-CO pathways and direct CO2 insertion pathways. The use of this process is ever-increasing and has expanded the scope of CO2 utilization to produce novel, high value-added or bulk chemicals, and has promoted sustainable chemistry. This review summarizes the recent advances in transition-metal-catalyzed carbonylations with CO2/H-2 and discusses the perspectives and challenges of further research.

Creating cost transparency to support strategic planning in complex chemical value chains

Accurate and detailed cost information is crucial for decision makers when deciding about important long-term business aspects, such as capacity investments, the product range to offer or the markets to serve. The economic assessment of these options is supported by a company’s accounting team and is based on analyses that the accountants usually run in spreadsheet models of the value chain under consideration. However, solely working with the available cell formula functionality requires model simplifications, e.g., when it comes to cyclic production relationships or by-products, two common characteristics in the chemical industry. This might lead to a distorted cost and profitability assessment. In this paper, we present a two-step approach for creating detailed cost transparency, which easily takes the production and supply chain characteristics into account. In a first step, we propose a mathematical programming model to determine the optimal procurement, production, and sales quantities. Such models can easily account for the existing operations and technical constraints. In a second step, we complement the first-stage results with another mathematical programming model that takes the predetermined quantities as inputs and allocates the variable and fixed costs to the individual products. To clarify the approach and highlight its benefits, we discuss it in the context of a real-world implementation in the chemical industry at BASF. Due to by-products, the compact formulation of the cost-allocation model is non-linear. We develop a workaround to convert it into a linear and easily solvable one.

Direct Synthesis of Methyl Formate from CO2 With Phosphine-Based Polymer-Bound Ru Catalysts.

Methyl formate was produced in one pot through the hydrogenation of CO2 to formic acid/formate followed by an esterification step. The route offers the possibility to integrate renewable energy into the fossil-based chemical value chain. In this work, a phosphine-polymer-anchored Ru complex was shown to be an efficient solid catalyst for the direct hydrogenation of CO2 to methyl formate. The 1,2-bis(diphenylphosphino)ethane-like polymer presented the highest activity with a turnover number (TON) of up to 3401 at 160 °C. The reaction parameters were systemically investigated to optimize the reaction towards the formation of methyl formate. This catalyst could be reused seven times without a significant decrease in activity. Evolution of the catalytic Ru center during the reaction was revealed, and a possible reaction mechanism was proposed.

Radiation-based model reduction for the optimization of high temperature tube bundle reactors: Synthesis of hydrogen cyanide

Key intermediates of the chemical value chain such as hydrogen cyanide and synthesis gas are produced in high temperature tube bundle reactors. Process intensification plays an essential role toward a more sustainable production of these compounds. In this contribution the tube bundle arrangement is optimized for the case study of hydrogen cyanide production. Using physics-based model reduction, the bundle reactor is modeled in two dimensions. Gas layer emissivity and tube total view factors are identified as crucial parameters for radiative heat transfer in the furnace. Using an equidistant spacing of 0.052 m, the average yield of HCN is improved by 0.5% and the variance of tube yields is reduced. Overall, staggered arrangements are superior to aligned bundle arrangements. Based on these findings, rule-of-thumb-type tube bundle design heuristics can be derived for any specific furnace design having a potentially large impact on the economic and ecologic footprint of these processes.