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.

Overcoming a Conceptual Limitation of Industrial ε-Caprolactone Production via Chemoenzymatic Synthesis in Organic Medium.

The multi-10.000 tons scale manufactured chemical ε-caprolactone attracts high industrial interest due to its favorable biodegradability properties. However, besides being of petrochemical origin yet, its industrial production has a conceptual limitation that is the difficult extraction of this highly water-soluble monomer from the water phase resulting from the aqueous solution of H2O2 applied as reagent. In this contribution, we report a chemoenzymatic cascade starting from bio-based phenol, which makes use of O2 instead of H2O2 and runs in pure organic medium, thus requiring only simply decantation and distillation as work-up. In a first step, phenol is hydrogenated quantitatively to cyclohexanol under solvent-free conditions with a Ru-catalyst. After simple removal of the heterogenous catalyst, cyclohexanol is converted to ε-caprolactone in a biocatalytic double oxidation with very high yields just requiring O2 as reagent. This biocatalytic process proceeds in pure organic medium, thus avoiding tedious extraction to isolate the highly water-soluble ε-caprolactone and enabling a dramatically simplified work-up by only centrifugal separation of lyophilized whole cells and solvent removal. This oxidation is accomplished using a tailor-made recombinant whole-cell catalyst containing an alcohol dehydrogenase and a cyclohexanone monooxygenase mutant.

Review and perspectives on TS-1 catalyzed propylene epoxidation.

Titanium silicate zeolite (TS-1) is widely used in the research on selective oxidations of organic substrates by H2O2. Compared with the chlorohydrin process and the hydroperoxidation process, the TS-1 catalyzed hydroperoxide epoxidation of propylene oxide (HPPO) has advantages in terms of by-products and environmental friendliness. This article reviews the latest progress in propylene epoxidation catalyzed by TS-1, including the HPPO process and gas phase epoxidation. The preparation and modification of TS-1 for green and sustainable production are summarized, including the use of low-cost feedstocks, the development of synthetic routes, strategies to enhance mass transfer in TS-1 crystal and the enhancement of catalytic performance after modification. In particular, this article summarizes the catalytic mechanisms and advanced characterization techniques for propylene epoxidation in recent years. Finally, the present situation, development prospect and challenge of propylene epoxidation catalyzed by TS-1 were prospected.

Sustainability in Industrial Processes.

Thoughts of Claudia Ley, Editor-in-Chief of Ullmann's Encyclopedia of Industrial Chemistry, and Henrique Teles, board member of ChemSusChem and Ullmann's Encyclopedia, on the progress that is being made in industrial chemistry, which is as important as progress made in academia.

Bimetal catalyst based on Fe and Co supported on Al pillared interlayer clays: Preparation, reactivity and mechanism for SCR-CH4.

Montmorillonite was used as raw clay to prepare the Al-pillared interlayer clay (Al-PILC) as support by impregnation methods. Co and Fe were loaded in series on Al-PILC to prepare the bimetal catalysts (Fe-Co/Al-PILC). The SCR-CH4 was evaluated in a fixed bed reactor and the results indicated that 0.27Fe-Co/Al-PILC exhibited 100% N2 selectivity and above 63% NO conversion in the presence of 10% H2O, and the introduction of Fe significantly improved the Co/Al-PILC catalyst's resistance to H2O and SO2. Characterization showed that Lewis and Brønsted acids co-existed on the catalyst surface, and the Lewis acid was the dominant active acid site and enhanced the activation of methane over the 0.27Fe-Co/Al-PILC. Fe promoted the formation of isolated Co2+ and CoO species, and the isolated Fe3+ particles improved CH4-SCR performance. The reaction route was proposed based on in situ DRIFTS tests and the active intermediates were mainly various nitrates and nitromethane (CH3NO2).

Greatly Intensified Guest Exchange Strategy for Highly-Efficient Activation of Metal-Organic Frameworks.

The preservation and accessibility of pores are prerequisites to the application of metal-organic frameworks (MOFs). Activation is a key step to eliciting rich features of pores, but it needs a repeated solvent-exchange process which is tedious and time/cost-consuming. Herein, a facile strategy for highly-efficient activation of MOFs utilizing rotating packed bed is proposed. With the tremendous enhancement of molecular mixing and mass transfer in high-gravity and strong-shearing surrounding, nine representative MOFs are completely activated within 2 h without structural change. Compared with conventional process, this activation displays surprising efficiency by accelerating the diffusion of solvents and redissolution of residual reactants in the pores. The complete activation time can be significantly shortened by over 90%. As a proof-of-concept, the methane storage of as-activated UiO-66 is five times that of as-synthesized UiO-66. This strategy provides a potential platform with industrial worth for the activation of MOF materials with ultra-high efficiency and versatility.

The Rise of Trichlorides Enabling an Improved Chlorine Technology.

Chlorine plays a central role for the industrial production of numerous materials with global relevance. More recently, polychlorides have been evolved from an area of academic interest to a research topic with enormous industrial potential. In this minireview, the value of trichlorides for chlorine storage and chlorination reactions are outlined. Particularly, the inexpensive ionic liquid [NEt3 Me][Cl3 ] shows a similar and sometimes even advantageous reactivity compared to chlorine gas, while offering a superior safety profile. Used as a chlorine storage, [NEt3 Me][Cl3 ] could help to overcome the current limitations of storing and transporting chlorine in larger quantities. Thus, trichlorides could become a key technique for the flexibilization of the chlorine production enabling an exploitation of renewable, yet fluctuating, electrical energy. As the loaded storage, [NEt3 Me][Cl3 ], is a proven chlorination reagent, it could directly be employed for downstream processes, paving the path to a more practical and safer chlorine industry.

Insights on production mechanism and industrial applications of renewable propylene glycol.

Propylene glycol is a ubiquitous sustainable chemical that have several industrial applications. It can be used as a non-toxic antifreeze, moisturizers, and in cosmetics products. Commercial production of propylene glycol uses petroleum-based propylene oxide. Therefore, there is a need to develop alternative and renewable propylene glycol production routes. Renewable propylene glycol can be produced from catalytic hydrogenolysis of glycerol. This study reviews different catalyst for glycerol hydrogenolysis, the reaction mechanism, and process challenges. Additionally, previous studies related to the economic and environmental assessment of propylene glycol production are presented in detail. The technology readiness level of different production pathways were outlined as well as the challenges and future direction of propylene glycol production from glycerol and other renewable feedstocks. Catalytic transfer hydrogenolysis, a process that uses renewable H-donors in liquid medium for hydrogenolysis reaction is also discussed and compared with conventional hydrogenolysis.

Preface to Special Issue on Biocatalysis as Key to Sustainable Industrial Chemistry.

In their Editorial for the Special Issue on Biocatalysis as Key to Sustainable Industrial Chemistry, Guest Editors Andrés Alcántara, Pablo Domínguez de María, Jennifer Littlechild, and Roland Wohlgemuth and their co-workers on the European Society of Applied Biocatalysis' (ESAB) Working Group on Sustainable Chemistry Martin Schürmann and Roger Sheldon discuss the Special Issue and the importance of biocatalysis in carrying out cutting-edge industrial chemistry in a sustainable way, as well as the future prospects for the field.

Synthesis and Biodegradation Studies of Low-Dispersity Poly(acrylic acid).

Poly(acrylic acid) (PAA) is produced on an industrial scale and widely-used in applications such as personal care products and cleaning formulations that end up "down-the-drain." Relatively high molecular weight PAA is considered poorly biodegradable, but little is known about the biodegradability of low molecular weight PAA at the wastewater treatment plant according to current regulatory and industrial Organization for Economic Co-operation and Development (OECD) standards. The synthesis, separation, and characterization of a series of ultralow dispersity PAA oligomers (i.e., D < 1.10) in the molecular weight range Mn ≈ 350-1200 Da and the results of biodegradability testing are reported. Miniaturized, high-throughput screening studies in a parallel respirometer reveals a strong trend toward lower biodegradation at higher molecular weight; these results are confirmed and expanded using standardized method OECD 301F. Biodegradability reaches ≈40% at Mn = 380 Da, ≈26% at Mn = 770 Da, and ≈17% at Mn = 1190 Da for discrete polyacid oligomers. These data not only shed light on potential biodegradation mechanisms for linear PAA, but also may inspire the future design of biodegradable PAA-containing macromolecules.

Biocatalysis as Key to Sustainable Industrial Chemistry.

The role and power of biocatalysis in sustainable chemistry has been continuously brought forward step by step to its present outstanding position. The problem-solving capabilities of biocatalysis have been realized by numerous substantial achievements in biology, chemistry and engineering. Advances and breakthroughs in the life sciences and interdisciplinary cooperation with chemistry have clearly accelerated the implementation of biocatalytic synthesis in modern chemistry. Resource-efficient biocatalytic manufacturing processes have already provided numerous benefits to sustainable chemistry as well as customer-centric value creation in the pharmaceutical, food, flavor, fragrance, vitamin, agrochemical, polymer, specialty, and fine chemical industries. Biocatalysis can make significant contributions not only to manufacturing processes, but also to the design of completely new value-creation chains. Biocatalysis can now be considered as a key enabling technology to implement sustainable chemistry.

Systems level roadmap for solvent recovery and reuse in industries.

Recovering waste solvent for reuse presents an excellent alternative to improving the greenness of industrial processes. Implementing solvent recovery practices in the chemical industry is necessary, given the increasing focus on sustainability to promote a circular economy. However, the systematic design of recovery processes is a daunting task due to the complexities associated with waste stream composition, techno-economic analysis, and environmental assessment. Furthermore, the challenges to satisfy the desired product specifications, particularly in pharmaceuticals and specialty chemical industries, may also deter solvent recovery and reuse practices. To this end, this review presents a systems-level approach including various methodologies that can be implemented to design and evaluate efficient solvent recovery pathways.

Coking-resistant dry reforming of methane over Ni/γ-Al2O3 catalysts by rationally steering metal-support interaction.

The coking issue is the main challenge for dry reforming of methane (DRM) over Ni-based catalysts. Herein, we excavate the reasons for the enhanced coking resistance of the bounded Ni over the free state Ni in Ni/γ-Al2O3 catalysts for DRM. Rational metal-support interaction of the bounded Ni would facilitate desorption of CO, thus suppressing CO disproportionation and decreasing carbon deposition. The higher activity of the bounded Ni is ascribed to better methane cracking ability, stronger adsorption, and activation of CO2 by forming polydentate carbonate. The better activation of CO2 over the bounded Ni would also contribute to the gasification of formed coke. We gain an insight into the anti-coking mechanism of DRM determined by metal-support interaction in Ni/γ-Al2O3 catalysts through mechanistic studies. It is believed that our findings would enlighten the design of more efficient catalysts for DRM.

Carbon neutral manufacturing via on-site CO2 recycling.

The chemical industry needs to significantly decrease carbon dioxide (CO2) emissions in order to meet the 2050 carbon neutrality goal. Utilization of CO2 as a chemical feedstock for bulk products is a promising way to mitigate industrial emissions; however, CO2-based manufacturing is currently not competitive with the established petrochemical methods and its deployment requires creation of a new value chain. Here, we show that an alternative approach, using CO2 conversion as an add-on to existing manufactures, can disrupt the global carbon cycle while minimally perturbing the operation of chemical plants. Proposed closed-loop on-site CO2 recycling processes are economically viable in the current market and have the potential for rapid introduction in the industries. Retrofit-based CO2 recycling can reduce annually between 4 and 10 Gt CO2 by 2050 and contribute to achieving up to 50% of the industrial carbon neutrality goal.

Current and future lithium-ion battery manufacturing.

Lithium-ion batteries (LIBs) have become one of the main energy storage solutions in modern society. The application fields and market share of LIBs have increased rapidly and continue to show a steady rising trend. The research on LIB materials has scored tremendous achievements. Many innovative materials have been adopted and commercialized by the industry. However, the research on LIB manufacturing falls behind. Many battery researchers may not know exactly how LIBs are being manufactured and how different steps impact the cost, energy consumption, and throughput, which prevents innovations in battery manufacturing. Here in this perspective paper, we introduce state-of-the-art manufacturing technology and analyze the cost, throughput, and energy consumption based on the production processes. We then review the research progress focusing on the high-cost, energy, and time-demand steps of LIB manufacturing. Finally, we share our views of challenges in LIB manufacturing and propose future development directions for manufacturing research in LIBs.

Spurring low-carbon electrosynthesis through energy and innovation policy.

Reaching the climate targets set in the Paris Agreement on climate change requires decarbonizing all parts of the global economy. The electrification of industry processes-and more specifically, electrosynthesis (ES)-is an important decarbonization mechanism. To tap into this mechanism's potential and accelerate the decarbonization of these processes, I argue that public policy needs to perform two tasks. First, energy policy needs to enable the provision of CO2 emissions-free baseload electricity. Second, innovation policy needs to accelerate cost reductions for ES. Here, I discuss why this is the case, what the challenges are, how policy makers can address them, and how political ambition can be increased.

Efficient Industrial Organic Synthesis and the Principles of Green Chemistry.

Making industry greener: Many principles for the economic production of organic bulk chemicals, the syntheses of which have potentially the highest environmental impact, currently overlap with principles of green chemistry. However, there remain enough challenges in making industrial organic synthesis even greener while keeping them efficient, which requires research and innovative processes. How efficient industrial organic chemistry can go hand in hand with principles of green chemistry is reflected in this Science Voices article.

Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses.

Sugar alcohols are of great importance for the food industry and are promising building blocks for bio-based polymers. Industrially, they are produced by heterogeneous hydrogenation of sugars with H2 , usually with none to low stereoselectivities. Now, we present a homogeneous system based on commercially available components, which not only increases the overall yield, but also allows a wide range of unprotected ketoses to be diastereoselectively hydrogenated. Furthermore, the system is reliable on a multi-gram scale allowing sugar alcohols to be isolated in large quantities at high atom economy.

Tunable Selectivity and High Efficiency of CO2 Electroreduction via Borate-Enhanced Molten Salt Electrolysis.

Converting CO2 into value-added chemical fuels and functional materials by CO2 reduction reaction (CO2RR) is conducive to achieving a carbon-neutral energy cycle. However, it is still challenging to efficiently navigate CO2RR toward desirable products. Herein, we report a facile strategy to extend product species in borate-containing molten electrolyte at a positively shifted cathodic potential with a high current density (e.g. 100 mA/cm2), which can selectively electro-transform CO2 into desired products (either CO or solid carbon nanofibers, respectively reaching a high selectivity of ∼90%). The borates can act as a controller of electrolyte alkalinity to buffer the concentration of sequentially generated O2- during CO2RR, positively shifting the reduction potential of the captured CO2 and concurrently extending the product species. The sustainable buffering effect is available under CO2 atmosphere. Compared with borate-free electrolyte, the CO2 conversion efficiency is over three times higher, while the electrolysis energy consumption is decreased by over 40%.

A Perspective on Biofuels Use and CCS for GHG Mitigation in the Marine Sector.

The greenhouse gas (GHG) emissions of the marine sector were around 2.6% of world GHG emissions in 2015 and are expected to increase 50%-250% to 2050 under a "business as usual" scenario, making the decarbonization of this fossil fuel-intensive sector an urgent priority. Biofuels, which come in various forms, are one of the most promising options to replace existing marine fuels for accomplishing this in the short to medium term. Some unique challenges, however, impede biofuels penetration in the shipping sector, including the low cost of the existing fuels, the extensive present-day refueling infrastructure, and the exclusion of the sector from the Paris climate agreement. To address this, it is necessary to first identify those biofuels best suited for deployment as marine fuel. In this work, the long list of possible biofuel candidates has been narrowed down to four high-potential options-bio-methanol, bio-dimethyl ether, bio-liquefied natural gas, and bio-oil. These options are further evaluated based on six criteria-cost, potential availability, present technology status, GHG mitigation potential, infrastructure compatibility, and carbon capture and storage (CCS) compatibility-via both an extensive literature review and stakeholder discussions. These four candidates turn out to be relatively evenly matched overall, but each possesses certain strengths and shortcomings that could favor that fuel under specific circumstances, such as if compatibility with existing shipping infrastructure or with CCS deployment become pivotal requirements. Furthermore, we pay particular attention to the possibility of integrating deployment of these biofuels with CCS to further reduce marine sector emissions. It is shown that this aspect is presently not on the radar of the industry stakeholders but is likely to grow in importance as CCS acceptability increases in the broader green energy sector.