Development Of Chemical Processes Research Articles

Selective Photocatalytic Benzene Oxidation Using Iron‐Carbon Nitride Fragments Functionalized with Cyamelurate‐Like Groups

Carbon nitrides have emerged as promising supports for catalytically active metals in various chemical reactions. Among these, the selective oxidation of benzene to phenol stands out as particularly challenging within the chemical industry due to its traditionally low yields and complex reaction pathways. In our current investigation, we have focused on the synthesis of ionic carbon nitride fragments via a straightforward alkaline hydrolysis method. These fragments demonstrate a remarkable ability to stabilize iron cations within the carbon nitride structure (Frag‐Fe), resulting in a highly efficient photocatalyst for benzene oxidation. Employing hydrogen peroxide as the oxidant in a single‐step reaction, we achieved an impressive 47% yield of phenol using Frag‐Fe at 12 hours, with negligible production of CO2 as a byproduct. This compelling outcome underscores the effectiveness of our alkaline synthesis approach in generating carbon nitride‐based photocatalysts with exceptional activity for C‐H oxidation reactions. Our findings not only contribute to the advancement of carbon nitride‐based catalysis, but also hold significant promise for the development of more sustainable and efficient chemical processes in the future.

Sustainable Valorization of CO2 through Nuclear Power-to-X Pathways

Some of the issues concerning energy security and climate change can be addressed by employing nuclear power (NP) to supply the energy required for the conversion of carbon dioxide (CO2) into chemicals, products, and materials. Nuclear energy represents a neutral carbon source that can be generated sustainably, reliably, and consistently. Nuclear power plants (NPPs) could supply energy in the form of heat, electricity, and ionizing radiation to drive CO2 chemical reactions underpinning NP-to-X type of pathways. CO2 conversion processes are either commercially available or emerging technologies at different developmental maturity stages. This work reviews the published literature (articles and patents) that reports R&D results and the understanding and development of chemical reactions and processes, as well as the efforts in integrating NPPs and chemical processes (CPs). As will be made evident, a new industrial era for the manufacturing of decarbonized chemicals, products, and materials will be possible by developing and implementing new (more energy- and carbon-efficient) processes responding to the NP-to-X pathways. This new decarbonizing platform not only contributes to achieving net zero goals but also broadens the NPP product beyond electricity.

IMPROVEMENT OF METHODS FOR DECOMPOSING MOLYBDENUM IN INDUSTRIAL PRODUCTS

The study of methods for extracting molybdenum into solutions from industrial ores and concentrates is an important task in the mining and metallurgical industry. Molybdenum (Mo) is used in the production of steel, alloys, electrode materials, and catalysts. The purpose of this work is to increase the efficiency of decomposition of molybdenum-containing materials, reduce production and processing costs, and minimize environmental impact. The tasks include the development of new chemical and metallurgical processes for processing various ores and concentrates, involving their decomposition and the extraction of molybdenum into a solution. Methodology. The study used microwave autoclave decomposition methods and chemical decomposition (acidic and fusion). The composition of the solution was determined using the atomic absorption method. The novelty of the research lies in the use of isolated microwave autoclave decomposition, which combines high efficiency and environmental safety. Results and discussion. The study compared the results obtained by the method of acidic decomposition and fusion in an open system with those from microwave autoclave decomposition in a closed system. Each method has its own advantages and disadvantages. The results of acidic and autoclave decompositions were similar to each other, while the results of fusion showed increased metal contents. The values of decomposition methods for standard copper and molybdenum concentrates showed results of 0.1-2.4%, respectively. The values of acidic (0.8%; 0.98%) and autoclave (0.9%; 1.04%) decompositions for samples from Chirchik and Stepnogorsk concentrates yielded similar results. Conclusion. The results of the decomposition methods of the materials do not differ significantly from each other from a production or industrial point of view. The analysis results can be applied in practice or used as reference values for scientific research.

Understanding the Effects of Forced and Bubble-Induced Convection in Transport-Limited Organic Electrosynthesis

Organic electrosynthesis offers a sustainable path to decarbonize the chemical industry by integrating renewable energy in chemical manufacturing. However, achieving the selectivity and energy efficiency required for industrial applications is challenging due to the inherent mass transport limitations of most electro-organic reactions. Electrochemical reactions rely on transport of reactants to the electrode surface and become mass transport-limited when the reactant diffusion rate is lower than the reaction rate at the electrode. In organic electrosynthesis with several possible products, mass transport limitations can result in decreased selectivity towards the desired product as the various reaction pathways compete. Convection can mitigate mass transport limitations, but fundamental engineering guidelines for selecting and scaling up convection methods in electrochemical systems do not exist. As a result, the impact of convection on industrial-scale complex organic electrochemical processes remain poorly understood. Here we show that the Sherwood number (Sh)—the ratio of convective mass transport to diffusive mass transport—is a crucial metric to characterize mass transport, determine reactor performance, and enable effective scale-up. We investigate the interplay between mass transport and electrochemical reaction rates under convective flows in the context of the electrosynthesis of adiponitrile, one of the largest organic electrochemical processes in the industry. We use experiments and data-driven predictive models to demonstrate that forced liquid convection and bubble-induced convection produce nearly equivalent mass transport conditions when the corresponding Sherwood numbers are equal. This conclusion shows that the Sherwood number characterizes the mass transport condition independent of the underlying convection mechanism. Additionally, we show that the reactor performance scales with the Sherwood number for a given current density and reactant concentration. This scaling enables accurate prediction of performance irrespective of the convection method, and demonstrates that adiponitrile Faradaic efficiencies of >80% can be achieved for current densities of up to 200 mA/cm2 when Sh > 100. Our results provide guidelines for the design and selection of convection methods, from lab to industrial scale, and contribute to the development of more sustainable chemical manufacturing processes.

The Catalytic Potential of Modified Clays: A Review

The need for innovative catalysts and catalytic support materials is continually growing due to demanding requirements, stricter environmental demands, and the ongoing development of new chemical processes. Since about 80% of all industrial processes involve catalysts, there is a continuing need to develop new catalyst materials and supports with suitable qualities to meet ongoing industrial demands. Not only must new catalysts have tailored properties, but they must also be suitable for large-scale production through environmentally friendly and cost-effective processes. Clay minerals, with their rich history in medicine and ceramics, are now emerging as potential catalysts. Their transformative potential is exemplified in applications such as hydrogenating the greenhouse gas CO2 into carbohydrate fuel, a crucial step in meeting the rising electrical demand. Moreover, advanced materials derived from clay minerals are proving their mettle in diverse photocatalytic reactions, from organic dye removal to pharmaceutical pollutant elimination and photocatalytic energy conversion through water splitting. Clay minerals in their natural state show a low catalytic activity, so to increase their reactivity, they must be activated. Depending on the requirements of a particular application, selecting an appropriate activation method for modifying a natural clay mineral is a critical consideration. Traditional clay mineral processing methods such as acid or alkaline treatment are used. Still, these have drawbacks such as high costs, long processing times, and the formation of hazardous by-products. Other activation processes, such as ultrasonication and mechanical activation routes, have been proposed to reduce the production of hazardous by-products. The main advantage of ultrasonication and microwave-assisted procedures is that they save time, whereas mechanochemical processing is simple and efficient. This short review focuses on modifying clay minerals using various new methods to create sophisticated and innovative new materials. Recent advances in catalytic reactions are specifically covered, including organic biogeochemical processes, photocatalytic processes, carbon nanotube synthesis, and energy conversion processes such as CO2 hydrogenation and dry reforming of methane.

Mechanochemical and Microwave Multistep Organic Reactions

Abstract: The development of more sustainable chemical reactions and processes has been the focus of recent research activities. Advances in the field of organic synthesis have led to the emergence of new methodologies and techniques involving non-conventional energy sources. These include the applications of mechanical energy (mechanochemistry) and microwave radiation (MW) methods. This article reviews the advances in multistep organic synthesis of biologically relevant organic molecules using mechanochemistry and microwave techniques. Among them, various heterocyclic molecules (with nitrogen, oxygen, and sulphur atoms), amides, and peptides have been synthesized by multistep mechanochemical or MW reactions. Performing multiple synthetic steps using more sustainable methods shows cumulative advantages over multistep processes under conventional conditions in terms of reduced solvent use, shorter reaction times, better turnovers, and reaction yields. Simplification of protocols by carrying out two or more reaction steps in the same reaction vessel is another advantage of multistep syntheses.

Development of novel hybrid pre-separation/extractive reactive distillation processes for the separation of methanol/methyl acetate/ethyl acetate

The treatment of waste streams is an important research topic for the sustainable development of chemical process. Recently, reactive distillation-based (RD) processes with ethylene oxide hydrolysis have been developed to separate water-containing azeotropic mixtures. To separate Serafimov’s class 2.0–2b mixtures containing methanol/methyl acetate, a methyl acetate transesterification reaction between propylene glycol monomethyl ether is introduced to convert methyl acetate to methanol and coproduce produce propylene glycol monomethyl ether acetate as advanced solvents. Three-column reactive-extractive distillation (TCRED) and extractive-reactive distillation (TCERD), and double-column pre-separation-reactive distillation (DCPSRD) processes, are proposed. Then, we use a parallel genetic algorithm to optimize processes to maximize total net revenue. The case study is methanol/methyl acetate/ethyl acetate. Though TCRED is not suitable due to the occurrence of ethyl acetate transesterification reactions, to compare economic performances of three RD-based processes, TCRED is regarded as a pseudo process. The total net revenue of three RD-based processes is relatively larger than (∼20 % increase) that of the conventional extractive distillation process. Compared with TCRED process, TCERD and DCPSRD can achieve $582336 and $1045995 increase in TNR, 27.43 % and 49.99 % TAC reduction, respectively. In summary, proposed RD-based processes are promising to separate Serafimov’s class 2.0–2b mixtures containing methanol/methyl acetate, especially TCRED and DCPSRD.

Networking Platform: For transfer and collaboration

AbstractA forum for chemists, chemical and process engineers promotes the sustainable growth of the Swiss chemical industry. It aims to emphasize the importance of chemical production and process development in research, education, industry and politics. This portrait reveals how it does this.

Automated high throughput workflow for rapid implementation of immobilized enzymes in chemical process development

Automated high throughput workflow facilitating the rapid optimization and development of immobilized enzymes – ready to be scaled – and thus matching the need for speed in modern drug development.

Thermocatalytic epoxidation by cobalt sulfide inspired by the material's electrocatalytic activity for oxygen evolution reaction.

New discoveries in catalysis by earth-abundant materials can be guided by leveraging knowledge across two sub-disciplines of heterogeneous catalysis: electrocatalysis and thermocatalysis. Cobalt sulfide has been reported to be a highly active electrocatalyst for the oxygen evolution reaction (OER). Under these oxidative conditions, cobalt sulfide forms oxidized surfaces that outperform directly prepared cobalt oxide in OER catalysis. We postulated that the catalytic activity of oxidized cobalt sulfide for OER could reflect a more general ability to catalyze O-transfer reactions. Herein, we show that cobalt sulfide (CoS x ) indeed catalyzes the epoxidation of cyclooctene, a thermal O-transfer reaction. Similarly to OER, the surface-oxidized CoS x formed under reaction conditions outperformed the directly prepared cobalt oxide, hydroxide, and oxyhydroxide for epoxidation catalysis. Another notable phenomenological parallel to OER was revealed by the electron paramagnetic resonance (EPR) analysis of all spent Co-based catalysts that showed significant structural changes and the formation of paramagnetic Co(ii) and Co(iv) species. Mechanistic investigations suggest that a higher density of Co(ii) and/or an easier formation of high-valent Co species in the case of surface-oxidized cobalt sulfide is responsible for its high activity as an epoxidation catalyst. Our results provide important insight into the surface chemistry of Co-based catalysts and show the potential of oxidized CoS x as an earth-abundant catalyst for O-transfer reactivity beyond OER. This work highlights the utility of bridging electrocatalysis and thermocatalysis for the development of more sustainable chemical processes.

Shaping a federal strategy for chemical recycling: Moving toward sensible applications of emerging technologies in US plastic waste management

AbstractPlastic waste management requires a diverse portfolio of strategies to avoid the most damaging environmental and social impacts of the plastic lifecycle and meet current national and international policy goals. The limitations of existing mechanical recycling methods for processing plastic waste have motivated the development and commercialization of chemical recycling processes. The novelty and diversity of such pathways beg critical questions of how these emerging technologies will fit within existing policy frameworks and contribute to recycling, plastic pollution, and waste management policy objectives. This work provides technical background into mechanical and chemical recycling methods, and policy background into differing modern approaches to chemical recycling at various levels of governance. Finally, this work summarizes key conflicts and crafts recommendations for future policy action on chemical recycling in three main areas: (1) defining an objective and identifying sensible applications for chemical recycling technologies, (2) filling gaps in existing knowledge and upholding environmental justice protections, and (3) implementing a suite of policies to complement chemical recycling's role in plastic waste management strategy.

Novoloop breaks ground on circular plastics pilot plant with Aether

On January 17, 2024, Novoloop announced the construction of a pilot plant in India. This collaboration with Aether Industries, a publicly listed specialty chemical manufacturer and chemical process development provider, is intended to demonstrate the scalability of Novoloop's Lifecycling™ technology. This technology transforms post-consumer plastic waste into monomers for the synthesis of virgin-quality, high-performance materials such as the company's Lifecycled™ thermoplastic polyurethane.

Functional Catalyst Molecular Sieves in Green Chemical Applications

With the development of green chemical industry and the continuous improvement of environmental awareness, the application of various catalysts in environmental protection has been widely concerned. As a green catalyst, molecular sieve catalyst has superior environmental performance, which is mainly reflected in its ability to improve the selectivity of reaction products, can be reused, good thermal stability and strong adaptability. This paper mainly introduces the types, development history, synthesis technology and application of zeolite catalysts, due to the development of science and technology, a large number of new synthetic zeolite catalysts are used in the field of catalysis and meet the requirements of green chemistry, and its synthesis technology is gradually trending towards environmental protection with the development of green chemistry. Zeolite catalysts are widely used in chemical industry and other fields, and their green environmental protection performance promotes the development of chemical processes in the direction of green chemicals.

Integrating experimental and computational approaches for deep eutectic solvent-catalyzed glycolysis of post-consumer polyethylene terephthalate

To achieve a sustainable and circular economy, developing effective plastic recycling methods is essential. Despite advances in the chemical recycling of plastic waste, modern industries require highly efficient and sustainable solutions to address environmental problems. In this study, we propose an efficient glycolysis strategy for post-consumer polyethylene terephthalate (PET) using deep eutectic solvents (DESs) to produce bis(2-hydroxyethyl) terephthalate (BHET) with high selectivity. Choline chloride (ChCl)- and urea-based DESs were synthesized using various metal salts and were tested for the glycolysis of PET waste; ChCl–Zn(OAc)2 exhibited the best performance. The DES-containing solvent system afforded a complete PET conversion, producing BHET at a high yield (91.6%) under optimal reaction conditions. The degradation mechanism of PET and its interaction with DESs were systematically investigated using density functional theory-based calculations. Furthermore, an intuitive machine learning model was developed to predict the PET conversion and BHET selectivity for different DES compositions. Our findings demonstrate that the DES-catalyzed glycolysis of post-consumer PET could enable the development of a sustainable chemical recycling process, providing insights to identify the new design of DESs for plastic decomposition.

Physical properties of deep eutectic solvents with efficient nitrogen removal capability

The efficient separation of N-compounds from fuel oil is of great significance for environmental protection and the development of sustainable chemical processes. In this work, eight quaternary acidic deep eutectic solvents (DESs) were prepared for the removal of basic N-compounds (pyridine) from simulated oils. Initially, the density, viscosity, conductivity, surface tension and refractive index values of the DESs were determined at 293.15–333.15 K. Based on these data, physical quantities such as molecular volume, standard entropy, lattice energy, activation energy of viscous flow, activation energy of conductivity, surface entropy, surface energy, speed of sound, molar Gibbs free energy, molar polarizability, molar polarizability, and free molar volume have been calculated. The effects of temperature, alkyl chain length of hydrogen bond acceptors (HBAs)/hydrogen bond donors (HBDs), structure of HBDs, and HBAs anion on the physical properties of DESs were systematically investigated. The internal interaction and property change of DESs are further studied. Finally, pyridine was extracted from the simulated oil using the prepared DESs. DESs consisting of tetrabutylammonium bromide and lactic acid had the highest extraction capacity under the same conditions. The extraction efficiency was found to be strongly correlated with the alkyl chain length and the acidity of the HBDs. This work is expected to provide information on the removal of N-compounds from both theoretical and industrial perspectives.

Harnessing a Biocatalyst to Bioremediate the Purification of Alkylglycosides.

As the world moves towards net-zero carbon emissions, the development of sustainable chemical manufacturing processes is essential. Within manufacturing, purification by distillation is often used, however this process is energy intensive and methods that could obviate or reduce its use are desirable. Developed herein is an alternative, oxidative biocatalytic approach that enables purification of alkyl monoglucosides (essential bio-based surfactant components). Implementing an immobilised engineered alcohol oxidase, a long-chain alcohol by-product derived from alkyl monoglucoside synthesis (normally removed by distillation) is selectively oxidised to an aldehyde, conjugated to an amine resin and then removed by simple filtration. This affords recovery of the purified alkyl monoglucoside. The approach lays a blueprint for further development of sustainable alkylglycoside purification using biocatalysis and, importantly, for refining other important chemical feedstocks that currently rely on distillation.

Efficient Synthesis of Furfural from Corncob by a Novel Biochar-Based Heterogeneous Chemocatalyst in Choline Chloride: Maleic Acid–Water

The use of plentiful and renewable feedstock for producing chemicals is fundamental for the development of sustainable chemical processes. Using fish scale as a biobased carrier, a novel biochar SO42−/SnO2-FFS heterogeneous chemocatalyst was prepared to catalyze furfural production from xylose-rich corncob-hydrolysates obtained from acid hydrolysis of corncob in a deep eutectic solvent (DES)–water system. By characterizing the physical as well as chemical properties of SO42−/SnO2-FFS by NH3-TPD, FT-IR, XPS, XRD, and SEM, it was shown that the chemocatalyst had Lewis/Brönsted acid centers, and its surface roughness could be well expanded to contact substrates. The corncob was initially hydrolyzed at 140 °C to obtain xylose-rich hydrolysate. Subsequently, SO42−/SnO2-FFS (3.6 wt.%) was used to catalyze the corn cob hydrolysate containing D-xylose (20.0 g/L) at a reaction temperature of 170 °C for 15 min. Additionally, ZnCl2 (20.0 g/L) was added. Ultimately, furfural (93.8 mM, 70.5% yield) was produced in the deep eutectic solvent ChCl:maleic acid–water (DESMLA–water = 10:90, v/v). A synergistic catalytic mechanism for transforming xylose-rich corncob-hydrolysate into furfural and byproducts were proposed using SO42−/SnO2-FFS as a chemocatalyst in DESMLA–water containing ZnCl2. Consequently, the efficient use of biochar SO42−/SnO2-FFS chemocatalysts for the sustainable synthesis of biobased furan compounds from biomass holds great promise in the future.

Production scale test for indirect cathodic reduction of indigo opens a route for greener denim

Textile and garment industry is one of the biggest industrial consumers of high quality water and belongs to most polluting industries worldwide. Development of textile chemical processes which allow reuse of chemicals and water thus is an imperative. Cathodic reduction of vat dyes e.g. indigo is a promising technology to replace non regenerable reducing agents in dyeing processes. Experiments at laboratory scale are not sufficient to achieve scalable results. In this study a full scale production test for replacement of dithionite based indigo reduction in denim production by cathodic dye reduction has been performed to demonstrate the potential of the technology. A 1000 A electrolyser was coupled to a open width yarn dyeing unit and 11,000 m (3,600 kg) of warp yarn was dyed with use of a cathodically regenerated iron-triethanolamine complex as reducing agent instead of a continuous dosage of dithionite into the dyebath. A time constant production was achieved over the full duration of the 5.5 h production. The dyed warp then was woven into denim fabric and only very minor colour deviations were observed between the electrochemically dye fabric and the reference quality, which demonstrates the ability of the technology to reproduce shade and ring-dying of a denim yarn. Model calculations to compare the chemical consumption of an electrochemical dye reduction with standard chemical processes indicate the importance of a recycling of the waste water by membrane filtration. Compared to a typical indigo range which consumes 100 g min−1 dithionite the chemical consumption of the new process falls below to 30% when 60% of the iron-complex therein is recovered. The demonstration of the technology in a full scale test can be understood as a relevant break through for future introduction of indirect cathodic dye reduction as cleaner technology in denim production.

Design of a Biocatalytic Flow Reactor Based on Hierarchically Structured Monolithic Silica for Producing Galactooligosaccharides (GOSs).

Climate change mitigation requires the development of greener chemical processes. In this context, biocatalysis is a pivotal key enabling technology. The advantages of biocatalysis include lower energy consumption levels, reduced hazardous waste production and safer processes. The possibility to carry out biocatalytic reactions under flow conditions provides the additional advantage to retain the biocatalyst and to reduce costly downstream processes. Herein, we report a method to produce galactooligosaccharides (GOSs) from a largely available feedstock (i.e.lactose from dairy production) using a flow reactor based on hierarchically structured monolithic silica. This reactor allows for fast and efficient biotransformation reaction in flow conditions.

RETRACTED:Exploring the intermolecular interactions in carbon disulfide dimer: An ab initio study using an improved Lennard–Jones potential energy surface for physical insights

AbstractCarbon disulfide dimer (CS2)2 is a model system that has been widely studied in the field of computational chemistry because of its relevance to a variety of chemical and biological processes. The (CS2)2 dimer is a relatively simple molecular system composed of two carbon disulfide (CS2) molecules interacting with each other through intermolecular forces. Despite its apparent simplicity, the (CS2)2 dimer exhibits a rich array of structural and dynamical properties that are of great interest to researchers. In this research, we present an ab initio study of the intermolecular interactions in the carbon disulfide dimer (CS2)2 using an improved Lennard–Jones (ILJ) potential with CCSD(T)/QZVPP calculations. The potential energy surface of (CS2)2 is calculated using high‐level quantum mechanical calculations based on the CCSD(T)/def2‐qzvpp method, which accurately accounts for electron correlation effects. The resulting potential energy surface is then fitted to an ILJ potential energy function, which includes both long‐range dipole–dipole interactions and short‐range repulsive interactions. The calculated potential energy surface reveals a rich variety of structural and dynamical properties of (CS2)2, including multiple minima and saddle points, which are sensitive to the relative orientation of the two CS2 molecules. It is essential to use extended basis sets to accurately incorporate the significant quadrupole moment of CS2, which we have calculated to be 2.44 a.u. The results of this study demonstrate the importance of using high‐level ab initio methods for the accurate calculation of potential energy surfaces in complex molecular systems such as (CS2)2. The use of an ILJ potential, which takes into account both dipole–dipole interactions and short‐range repulsive interactions, provides a more accurate and efficient approach for modeling intermolecular interactions in (CS2)2 and other similar systems. The results of this study will be useful for understanding the behavior of carbon disulfide dimers in different environments and for the development of new materials and chemical processes.