Sustainable Chemical Industry Research Articles

Boosting Dimethyl Carbonate Production from CO2 and Methanol using Ceria-Ionic Liquid Catalyst.

As a crucial strategy towards a sustainable chemical industry, the direct synthesis of dimethyl carbonate (DMC) from renewable carbon dioxide (CO2) and methanol (MeOH) is studied using CeO2 nanoparticles modified with 1-butyl-3-methylimidazolium hydrogen carbonate ([BMIm][HCO3]) devoid of stoichiometric dehydrating agents. The synthesized CeO2@[BMIm][HCO3] catalyst having high thermal stability harnesses the unique physicochemical properties of CeO2 and the ionic liquid to exhibit a DMC yield of 10.4 % and a methanol conversion of 16.1 % at optimal conditions (pressure of CO2=5 MPa; temperature=130 °C). The catalytic behavior of CeO2@[BMIm][HCO3] studied with a detailed XRD, XPS, CO2 and NH3-TPD, Raman spectroscopy, TGA, FTIR, SEM and TEM suggests that the synergy between the two catalytic components originating from an increased surface oxygen vacancies boosts the overall catalytic performance. After several recycling tests, the catalyst demonstrated no significant reduction in DMC yield and methanol conversion. This platform is an attractive approach to synthesize thermally stable nanoparticle@ionic liquid that retains and merges the physical attributes of both materials for producing useful bulk chemicals from readily available chemical resources.

Production of jet fuel cycloalkanes from 5‐(hydroxymethyl)furfural via cascade catalysis on Mg(Al)(Zr)O supported CuCo

AbstractCatalytic conversion of biomass‐derived 5‐(hydroxymethyl)furfural (5‐HMF) into carbon‐increased hydrocarbons as drop‐in energy‐rich biofuels has received a great deal of concern for the development of sustainable chemical industry. Here, we demonstrate a one‐pot conversion of 5‐HMF into C9‐alkanes on one single catalyst, acidic–basic layered double oxides (Mg(Al)(Zr)O) supported CuCo alloy. The well‐defined multifunctional catalytic sites with harmonious combination carry out cascade catalysis, affording C9‐alkanes (including 30% of more value‐added branched‐cycloalkanes) in 83% yield. The basic–acidic sites on Mg(Al)(Zr)O show high activity for aldol condensation of 5‐HMF and acetone, producing 4‐[5‐(hydroxymethyl)‐2‐furanyl]‐3‐buten‐2‐one (HAc) in a yield of >99%. The engineered Co–Cu–Co linkages on supported CuCo perform efficient hydrodeoxygenation, affording C9‐alkanes in a selectivity of 96% from HAc. C9‐cycloalkanes are generated from the cyclization of the corresponding monohydric alcohol intermediates by the synergy of acidic and CuCo sites in the hydrodeoxygenation reaction.

Prussian Blue Analogue-Derived Co3O4 as Catalysts for Enhanced Selective Oxidation of Cyclohexane Using Molecular Oxygen.

Selective conversion of inert C-H bonds in alkanes into high-value-added functional groups (alcohols, ketones, carboxylic acids, etc.) plays a vital role in establishing a green and sustainable chemical industry. Catalytic selective oxidation of cyclohexane to KA oil (cyclohexanol and cyclohexanone) is a typical representative of alkane functionalization. In this work, hollow cage-like Co3O4 (Co3O4-C) and particle Co3O4 (Co3O4-P) were synthesized by calcining two types of Prussian blue analogues (PBAs), which were used to catalyze the selective oxidation of cyclohexane. The Co3O4-C predominantly exposed (311) crystal plane is easier to adsorb cyclohexane than Co3O4-P, which is beneficial to shorten the induction period, accelerate the reaction rate, and improve the conversion. Consequently, Co3O4-C displayed a 10% conversion of cyclohexane within 1 h, and the KA oil selectivity reached 90%. The Co3O4-P exposed (220) crystal plane has a higher molar percentage of oxygen vacancies and more active oxygen species, as well as a strong cyclohexanone adsorption capacity, which is conducive to the deep oxidation of cyclohexanone to adipic acid and other diacid products. The mechanism analysis of cyclohexane oxidation catalyzed by PBA-based Co3O4 shows that it exemplifies the feasibility to tailor the surface of catalysts by modulating the PBAs, which ultimately influences their reaction performance for accelerating the reaction and maintaining high cyclohexane conversion and KA oil selectivity.

Mineral and bioresource exploitation for transformation and sustainability of the chemical industry in Zambia

Zambia depends mainly on copper mining and imports the bulk of chemicals needed for academic, domestic, and industrial consumption. The country has never had an economically viable chemical industry despite having vast minerals and bioresources key to the stimulation of a sustainable chemical industry. This paper proposes a theory of change model for the establishment of the chemical industry in Zambia to enhance economic growth. Availability of minerals and bioresources have been assumed as a strong driver to establish an economically viable chemical industry in Zambia. The paper discusses the economic status of Zambia, explains current economic drivers and proposes establishment of a chemical industry as a critical missing link to transform the economy. Briefly a thorough literature desk review was done with cue search words such as “Chemistry professionals Zambia”, “Policy Chemicals industry Zambia”, “Chemical industry Zambia”, “National Development Plan Zambia”, “Petrochemicals Zambia”, “Specialty chemicals Zambia”, “Gross Domestic product Zambia” in the Google scholar search engine. Results revealed that exclusion of chemical industry in policy formulation and implementation, lack of political will in promoting chemistry, underutilization of available mineral and bioresources remains part of the main reason for lack of growth of the chemical industry and serial failure of the seven national development plans to adequately plan for this since independence in 1964. The period from 1961 to 2021 was considered and the 2006 to 2021 comprising the fifth, sixth and seventh national development plans was isolated, and analysis of variance done for the three plans with respect to gross domestic product (GDP) and GDP per capita. There was a statistical significance for both parameters. A p = 0.0004 for GDP and 0.0003 for GDP per capita values showed that there was negative or almost no growth within each period of the national development plan. None of the seven development plans addressed a deliberate setting up of the chemical industry to reduce capital flight in terms of huge imports. Hence, we opine that the chemical industry in Zambia is desperately needed to provide agrochemicals and other specialty chemical feedstocks.

Integrating climate policies in the sustainability analysis of green chemicals

The grand transition towards green pathways for chemical production, alongside ambitious climate policies, could achieve 90% reduction in climate change impacts by 2050, while fossil routes offer a reduction of 10% in the best case.

(Invited) A Sustainable Future Fueled By Science: Recent Advances in Power-to-X Activities at Topsoe

Topsoe aims at being recognized as the global leader in carbon emission reduction technologies by 2024, by developing a wide range of energy-efficient solutions to produce sustainable transportation fuels, such as ammonia, methanol, and hydrogen. With over 80 years of expertise in heterogeneous catalysis and its application to industrial chemical processes, Topsoe is now striving to develop strong Power-to-X solutions to fuel the transition towards a sustainable chemical industry and energy infrastructure. One of the key-technology that Topsoe has envisioned for such transition is the solid oxide electrolysis cell (SOEC) technology, well-recognized as the most energy-efficient amongst the electrolysis solutions. Here, Topsoe’s expertise in heterogeneous catalysis also plays a role in ensuring an effective downstream catalytic conversion of SOEC products (H2, CO, or syngas) into green fuels and chemicals. To tackle climate change at the pace that our times impose, Topsoe is committing to a goal of net-zero greenhouse gas emissions by 2040. To reach such an ambitious goal, a large industrial scale application of the SOEC technology is necessary. Accordingly, Topsoe has announced the construction of a SOEC manufacturing facility in Denmark to produce electrolysis stacks and modules with a capacity of 500 MW per year, planned to be operational in 20251.In this presentation, Topsoe will provide an overview of its initiatives, lines of work and results in the field of SOECs, spanning from the thorough investigation of materials properties and electrode microstructure to the design and realization of a MW-sized electrolyzer plant. An extensive R&D effort is also directed towards increasing the lifetime of Topsoe’s fuel electrode-supported Ni/YSZ based cells, aiming at the development of robust and durable electrodes. The presentation will give examples of the analysis of electrode nano- and micro-structures by advanced characterization techniques, while illustrating the valuable role of impedance spectroscopy for the electrochemical characterization of the state-of-the-art cell performance. Finally, the presentation will also showcase results of stack testing applying Topsoe's stack technology for H2 production, as well as an update and outlook of Topsoe's efforts in upscaling its SOEC capacity. P. Blennow, T. Heiredal-Clausen, J. Rass-Hansen, J. B. Hansen; M. Hultqvist, and P.-G. Moses, in Proceedings - 14th Europrean Solid Oxide Fuel and SOE Cell Forum, p. A0304 (2022)

Biochar catalysts from animal manure: Production and application

Biochar is a sustainable functional material rich in carbon, derived from renewable resources such as biowaste (e.g., animal manure). It has unique chemical structure, large surface area and porosity, and tailored surface functional groups via proper activation and/or functionalization, thereby having high potential as heterogeneous catalytic materials applied to different chemical processes. Therefore, using animal manure-derived biochar as catalytic materials could be key to sustainable agriculture and chemical industries. Recent recognition of animal manure-derived biochars as versatile media of catalytic applications has encouraged rudimentary studies on their catalytic capabilities; however, the use of animal manure-derived biochar as catalytic materials has not been systematically reviewed yet. This review gives an overview of recent achievements in producing biochar from animal manure and subsequent modification methods. The catalytic properties of the biochar with respect to its production/modification recipes are also discussed. Furthermore, the catalytic performances of animal manure-derived biochars for different catalytic applications, such as transesterification, hydrogen production, hydrolysis, C–C coupling reactions, and electrodes for oxygen reduction reaction, supercapacitor, and lithium-ion battery, are evaluated.

Recovery of calcium and sulphur from phosphogypsum with zero by-product generation using a preparative vertical-flow electrophoresis system

Phosphogypsum has been a longstanding issue that poses environmental risks and economic pressure on society. Realizing the recycling of this waste is essential for achieving sustainable phosphorus chemical industry. In order to tackle this problem, this study examined the potential of using a preparative vertical-flow electrophoresis (PVFE) system with supporting media to recover calcium and sulphur from phosphogypsum without producing any by-products. NaOH was used to convert phosphogypsum into slaked lime and Na2SO4, with a maximum leaching efficiency of 98.6 % achieved at a NaOH concentration of 2 mol/L and a molar ratio of sodium to sulfur of 2.1. The slaked lime obtained met the quality standards outlined in the Chinese national standard (HG/T 4120–2009). Electrophoresis separation of the resulting Na2SO4 demonstrated that the NaOH effluent output could reach the desired concentration for reusing in the treatment of phosphogypsum. The addition of a solid supporting media (quartz sands) is the key to achieving the separation of Na2SO4. After considering the economic benefits, the optimal electrophoresis conditions for separating Na2SO4 were determined to be a supply voltage of 10 V and HRT of 240 min. These findings offer a directed and practical solution for the economical and effective recycling of phosphogypsum in phosphorus chemical industry.

The sustainable catalyst-cased chemical industry

The sustainable catalyst-cased chemical industry Dr Xochitl Dominguez Benetton, Senior Scientist and Project Coordinator from the Flemish Institute for Technological Research, walks us through the sustainable catalyst-based chemical industry which is very much a part of the FIREFLY project. In January 2023, funded with over €11 million by the Horizon Europe Programme, the FIREFLY project launched with an unwavering aim: transforming the catalyst-based chemical industry. By harnessing renewable energy for (electro)catalyst production from secondary resources, FIREFLY promises reduced costs and decreased reliance on metals and fossil fuels. This pioneering step toward circularity reimagines profitability by recycling industrial catalysts, forging a sustainable path for future industrial developments.

Solar-Driven Reforming of Methane and Nitrogen to Methanol and Ammonium on Iron-Modified Zeolite under Ambient Conditions in Water.

Artificial photosynthesis from selective methane oxidation or nitrogen reduction to value-added chemicals provides a promising pathway for the sustainable chemical industry, while still remaining a great challenge due to the extreme difficulty in C-H and N≡N bond cleavage under ambient conditions. Catalysts that can cocatalyze these two reactions simultaneously are rarely reported. Here, Fe-ZSM-5 with highly dispersed extra-framework Fe-oxo species enables efficient and selective photocatalytic conversion of methane and nitrogen to coproduce methanol and ammonia using H2O as the redox reagent under ambient conditions. The optimized Fe-ZSM-5 photocatalyst achieves up to 0.88 mol/molFe·h of methanol products with 97% selectivity. Meanwhile, the productivity of ammonia is 0.61 mol/molFe·h. In situ EPR and DRIFT studies disclose that water serves as a redox reagent to provide hydroxyl radicals for methane oxidation and protons for nitrogen hydrogenation. Quantum chemical calculations revealed that Fe-oxo species play a significant role in the coactivation of methane and nitrogen molecules, which lowers the energy barriers of rate-determining steps for methanol and ammonia generation.

Selective Analysis of Redox Processes at the Electrode Interface with Time-Resolved Raman Spectroscopy.

Electrochemistry and electrochemical reactions are increasingly important in the transition to a sustainable chemical industry. The electron transfer that drives such reactions takes place within nanometers of the electrode surface, and follow-up chemical reactions take place within the diffusion layer. Hence, understanding electrochemical reactions requires time-, potential-, and spatially resolved analysis. The confocal nature of Raman spectroscopy provides high spatial resolution, in addition to detailed information on molecular structure. The intrinsic weakness of nonresonant Raman scattering, however, is not sensitive enough for relatively minor changes to the solution resulting from reactions at the electrode interface. Indeed, the limit of detection is typically well above the concentrations used in electrochemical studies. Here, we show that surface-enhanced Raman scattering (SERS) and resonance Raman (rR) spectroscopy allow for spatially and time-resolved analysis of solution composition at (<1-2 nm) and near (within 5 μm) the electrode surface, respectively, in a selective manner for species present at low (<1 mM) concentrations. We show changes in concentration of species at the electrode surface, without the need for labels, specific adsorption, or resonance enhancement, using a SERS-active gold electrode prepared readily by electrochemical surface roughening. A combination of smooth and roughened gold electrodes is used to distinguish between surface and resonance enhancement using the well-known redox couples ferrocene and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). We discuss the impact of specific adsorption on the spectral analysis with the ruthenium(II) polypyridyl complex, [Ru(bpy)3]2+. The dual function of the electrode (surface enhancement and electron transfer) in the analysis of solution processes is demonstrated with the reversible oxidation of TMA (4,N,N-trimethylaniline), where transient soluble species are identified in real time, with rapid spectral acquisition, making use of localized enhancement. We anticipate that this approach will find use in elucidating electro(catalytic) reactions at electrode interfaces.

Synergy of Surface Phosphates and Oxygen Vacancies Enables Efficient Photocatalytic Methane Conversion at Room Temperature.

Room-temperature photocatalytic conversion of CH4 into liquid oxygenates with O2/H2O provides an appealing route for sustainable chemical industry, which, however, suffers from poor efficiency due to the undesired carrier kinetics and low yield of reactive oxygen species of the currently available photocatalysts. Here, we report an effective surface engineering strategy where concurrent constructions of oxygen vacancies and phosphate sites on TiO2 nanosheets address the above challenge. The surface oxygen vacancies and phosphates are respective acceptors of photogenerated electrons and holes for promoted separation and migration of charge carriers. Moreover, in addition to the facilitated activation of O2 to •OH by electrons at oxygen vacancies, the surface phosphates also facilely adsorb H2O via hydrogen bonds and thus effectively transfer holes to H2O for enhanced •OH production, thereby boosting CH4 conversion. As a result, compared with TiO2 sheets with only oxygen vacancies, a 2.8 times improvement in liquid oxygenate production with near-unity selectivity is achieved by virtue of the synergy of surface oxygen vacancies and phosphate sites, together with an unprecedent quantum efficiency of 19.8% under 365 nm irradiation.

Controlling the reaction network of Ni/silica derived conversion of bio-oil surrogate guaiacol

Replacing fossil carbon sources with green bio-oils is a promising route to switch to a sustainable chemical industry, although their high oxygen contents are challenging. Catalytic hydrodeoxygenation is a favored route to upgrade bio-oils to renewable fuels and basic chemicals. In this work, we investigated Ni/SiO2 catalysts with differing metal dispersity in continuous mode conversion of guaiacol with a statistical experimental design for 250 °C to 400 °C, 2 h up to 5 h time on stream (ToS) and subsequently different residence time besides other parameters. While low temperature (250 °C) promotes cyclohexanol formation from guaiacol, high temperature (400 °C) inhibits hydrogenation, leading to phenol and methane. For medium temperature (340 °C), the selectivity for cyclohexanone increases. Cyclohexanol and cyclohexanone (KA-oil) are the industrial basis for polyamide 6. Furthermore, we clarified the role of 2-methoxycyclohexanol (2MC) in the reaction network towards KA-oil for continuous-mode operation. Statistical analysis was used to predict and optimize product selectivity and yield, leading to the best yield of cyclohexanone/-ol at 327.5 °C, low ToS, medium residence time, high particle dispersity, and medium hydrogen pressure (15 bar(g)).

Ionic buffering biphase systems as catalysts and solvents for efficient dehydration of xylose and hemicellulose to furfural

The utilization of biomass instead of fossil resources for the synthesis of various chemicals is regarded as one of the most important strategies to realize sustainable and environmentally-friendly chemical industry. The design and development of suitable catalysts for biomass conversion are of particular significance. Herein, ionic buffering biphase systems (IBBSs) consisting of ionic buffering catalysts (IBCs) and an organic phase as extractant are proposed and developed for the dehydration of xylose and hemicellulose to furfural (FF). The systems can efficiently catalyze the conversion of xylose and hemicellulose to FF and significantly reduce the use of NaCl. High FF yields of 76.4% or 85.1% were realized with almost complete conversion of hemicellulose or xylose. The IBBSs have advantages of simple preparation, thermal stability, and low cost, not to mention the facts that they enable both the excellent extraction of FF product from aqueous phase to oil phase and the easy recycling of ionic buffering catalyst. This work offers a new strategy of designing and developing catalytic reaction-separation coupling systems for the efficient conversion of xylose and hemicellulose to FF.

Asymmetric C1 Extension of Aldehydes through Biocatalytic Cascades for Stereodivergent Synthesis of Mandelic Acids

AbstractThe development of mild, efficient, and enantioselective methods for preparing chiral building blocks from simple, renewable carbon units has been a long‐term goal of the sustainable chemical industry. Mandelate derivatives are valuable pharmaceutical intermediates and chiral resolving agents, but their manufacture relies heavily on highly toxic cyanide. Herein, we report (S)‐4‐hydroxymandelate synthase (HmaS)‐centered biocatalytic cascades for the synthesis of mandelates from benzaldehydes and glycine. We show that HmaS can be engineered to perform R‐selective hydroxylation by single‐point mutation, empowering the stereodivergent synthesis of both (S)‐ and (R)‐mandelate derivatives. These biocatalytic cascades enabled the production of various mandelate derivatives with high atom economy as well as excellent yields (up to 98 %) and ee values (up to &gt;99 %). This methodology offers an effective cyanide‐free technology for greener and sustainable production of mandelate derivatives.

Asymmetric C1 Extension of Aldehydes through Biocatalytic Cascades for Stereodivergent Synthesis of Mandelic Acids.

The development of mild, efficient, and enantioselective methods for preparing chiral building blocks from simple, renewable carbon units has been a long-term goal of the sustainable chemical industry. Mandelate derivatives are valuable pharmaceutical intermediates and chiral resolving agents, but their manufacture relies heavily on highly toxic cyanide. Herein, we report (S)-4-hydroxymandelate synthase (HmaS)-centered biocatalytic cascades for the synthesis of mandelates from benzaldehydes and glycine. We show that HmaS can be engineered to perform (R)-selective hydroxylation by single-point mutation, empowering the stereo-divergent synthesis of both (S)- and (R)-mandelate derivatives. We demonstrated that these biocatalytic cascades enabled the production of various mandelate derivatives with great atom economy, excellent yields (up to 98%) and enantiomeric excess (up to >99%). This methodology offers an effective cyanide-free technology for greener and sustainable production of mandelate derivatives.

Visible-light-driven g-C3N4/AgBiS2 S-scheme photocatalyst for N2 fixation and rhodamine B degradation

The design of photocatalysts, which uses free and available sunlight as a driving force to generate ammonia from nitrogen (N2) and remove organic pollutants from wastewater, is helpful to develop a sustainable chemical industry. The novel g-C3N4 nanosheet/AgBiS2 nanocomposite with visible-light response was successfully fabricated for the first time using a simple heating process. The purity, microstructure, morphology, photoelectrochemical, and electronic features of the obtained photocatalysts were studied using X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, photoluminescence, Brunauer–Emmer–Teller surface area, photocurrent responses, and electrochemical impedance spectroscopy. The g-C3N4 nanosheet/AgBiS2 nanocomposite possessed excellent photocatalytic activity for rhodamine B (RhB) degradation and N2 fixation upon visible illumination. The photocatalytic ammonium production reached 3780 μmol L−1 g−1 over g-C3N4 nanosheet/AgBiS2 nanocomposite, increases of 3.15- and 2.85-fold compared to that of g-C3N4 nanosheet and AgBiS2, respectively, as well as 99% improvement in degradation efficiency for RhB removal. The improved activity of g-C3N4 nanosheet/AgBiS2 nanocomposite can be ascribed to the formation of suitable heterojunction, suppressing the recombination of photogenerated charges, while facilitating their transfer. A plausible photocatalytic mechanism was proposed based on the experimental outcomes and photoelectrochemical properties. The g-C3N4 nanosheet/AgBiS2 nanocomposite proved to be significantly reusable and stable after five and four runs of N2 fixation and RhB degradation, respectively.

Structural Construction of Au–Pd Nanocomposite for Alkali-Free Oxidation of Benzyl Alcohol

A bimetallic Au-Pd system is an alternative candidate to catalyze primary alcohol oxidation and is of crucial importance for the sustainable chemical industry. However, understanding the bimetallic system in terms of the nanostructure is still challenging. Herein, we adopt the in situ colloid immobilization to obtain a series of bimetallic AuxPdy/CNT samples supported by carbon nanotubes (CNTs). Elaborate characterizations confirmed the bimetallic structure of AuPd alloy particles with randomly dispersed Pd2+ on the surface, forming the AuPd@PdO structure on CNTs. Unlike the monometallic samples, bimetallic ones, particularly Au1Pd1/CNT, efficiently transformed benzyl alcohol in an alkali-free mild condition. The DFT simulation confirmed the electron-rich gold atoms as a steric and electronic regulator to confine the electron-deficient Pd atoms in alloy particles. The interacted metal sites in the alloy system activated the alcohol with optimized adsorption configuration. Surface Pd2+ transported active oxygen to capture the abstracted H on alcohol. The collaboration between metal sites facilitated the transformation of benzyl alcohol to benzaldehyde with the selectivity of 91.8% by a fast TOF of 1274 h-1 at only 80 °C.

Highly efficient, amorphous bimetal Ni-Fe borides-catalyzed hydrogenolysis of 5-hydroxymethylfurfural into 2,5-dimethylfuran

Designing highly efficient non-noble metal catalyst for the selective hydrogenolysis of biomass derivatives to fuels and fine chemicals is a key pursuit for sustainable chemical industry but substantially challenging. In this contribution, we report, for the first time, the construction of amorphous bimetal Ni–Fe borides for efficient catalytic hydrogenolysis of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dimethylfuran (DMF) as a promising biofuel candidate. The as-prepared Ni1.52Fe0.36BOx catalyst afforded a near-quantitative DMF yield using ethanol as a green solvent under relatively mild operating conditions (1 MPa H2, 160 °C and 1 h), leading to an excellent DMF formation rate of 16.5 mmolDMF·gcat−1·h−1, which is 1.7–16.5 folds higher than the state-of-art nickel-based catalysts. Mechanistic investigations demonstrated that the Fe intervention is conductive to the generation of electron-enriched metal sites and powerful acidic sites in Ni1.52Fe0.36BOx catalyst, which favored the activation of hydrogen and the cleavage of C–O bond to accelerate the hydrogenolysis process. Moreover, Ni1.52Fe0.36BOx catalyst exhibited good recyclability as well as universality in the hydrogenolysis of various biomass-derived unsaturated aldehydes. This finding opens a new avenue for highly selective hydrodeoxygenation of renewable biomass feedstock to value-added chemicals with non-noble bimetal hybrids in a green and straightforward manner.

Computer‐Aided Molecular and Process Design

Increasing energy prices, tighter environmental regulation, and global competition urge the industry to optimize its processes for converting chemicals and energy. This optimization is far from trivial. Often, the key to major breakthrough relies not only on optimal process conditions but also on selecting suitable molecules as solvents, catalysts, or heat transfer fluids. This selection is highly coupled with the process itself: Choosing the right molecule is a crucial lever for process performance. However, the molecular search space is vast: more than 200 000 000 molecules have already been reported in the CAS registry. The search for the best molecule is thus the search for the needle in the haystack. The ultimate success of a process is only ensured if a molecule is selected based on its optimal process performance. Traditionally, however, the selection of a molecule and the design of the process have been approached sequentially and independently. Computer-aided molecular and process design (CAMPD) methods have been developed to tackle this challenge and systematically tailor molecules for a given application. Thereby, CAMPD can contribute to the transition towards a more sustainable energy and chemical industry, for example, by identifying energy-efficient carbon capture materials, sustainable working fluids for heat pumps, or green solvents for production processes. What is required for a successful application of CAMPD? The basis of a CAMPD problem is a computer-aided molecular design (CAMD) formulation that allows treating the molecular structure as a degree of freedom in an optimization problem. The CAMD formulation is linked with a property model that enables predicting all molecule properties required to evaluate the constraints and objective functions. To reflect the process performance, classical CAMD methods used simplified property-based indicators as the objective function. Recent CAMPD methods integrate detailed process models to assess process performance directly. The recent development of CAMPD/CAMD includes using advanced physically-based and data-driven property models. Moreover, the scope of predicted properties moves beyond the thermodynamic properties to environmental properties such as global warming potential. After decades of CAMPD/CAMD development, these tools have become available for industrial use by implementing CAMPD in flowsheet simulators. Thereby, the effort and required expert knowledge are greatly reduced to set up and solve a CAMPD problem. However, including such new tools in the daily workflow usually takes time. The urge to develop new sustainable processes hopefully will enhance the application of these CAMPD tools. In this special issue of Chemie Ingenieur Technik, authors from industry and academia present their latest developments and applications of CAMPD in energy and chemical engineering. The special issue cannot provide a comprehensive picture of this rapidly developing field. Thus, we aim to provide the reader with an impression of the current status and possible future directions of CAMPD. We hope readers will find inspiration in this special issue and thank all authors for their highly appreciated contributions! Norbert Asprion André Bardow Jonas Mairhofer Johannes Schilling