Sustainable Chemical Processes Research Articles

Lanthanum-Group Elements Promoted PtGa Catalysts for Propane Dehydrogenation: Exploring Key Performance Descriptors

Propylene, a crucial component in the chemical industry, holds a prominent position as the second-largest material within petrochemicals, serving as a foundational element for major synthetic materials and essential industrial chemicals such as acetone and isopropanol. Conventional propylene production methods confront environmental challenges, promoting the investigation of alternative pathways, such as direct propane dehydrogenation. While commercial PtSn or PtGa-based catalysts have demonstrated success in propane dehydrogenation, further enhancements are imperative to mitigate operational costs. Therefore, this study utilizes four lanthanum-group elements (La, Ce, Pr, and Nd) with varying loadings (1wt%, 3wt%, and 5wt%) to modify PtGa/Al2O3 catalyst, resulting in improved conversion, selectivity, and stability. Furthermore, this research establishes a clear structure-activity relationship based on some key performance descriptors, underscoring the effectiveness influence of reducibility, total acid concentration, and total coke content in conversion, selectivity, and stability. The impact of strong metal-support interactions on conversion and stability should also be considered, highlighting the complexities in accessing catalytic performances. The exploration of diverse performance descriptors revealed in this study contributes to the rational design of catalysts for propane dehydrogenation, addressing ongoing efforts to refine and tailor catalysts for efficient propane dehydrogenation. This study also offers valuable insights for optimizing catalytic performance across various industrial reactions, further advancing the field of catalysis and promoting sustainable and efficient chemical processes.

Towards sustainable chemical process design: Revisiting the integration of life cycle assessment

Towards sustainable chemical process design: Revisiting the integration of life cycle assessment

Coptis Root-Derived Hierarchical Carbon-Supported Ag Nanoparticles for Efficient and Recyclable Alkyne Halogenation

The advancement of green chemistry and sustainable chemical processes has been significantly facilitated by catalytic systems derived from plant roots, which also present substantial application prospects in the realm of chemical synthesis. This study utilized the roots of Rhizoma Coptidis as a support to successfully fabricate a silver-based nanocatalyst. By depositing silver nanoparticles onto the root material of Coptis chinensis and subjecting it to carbonization, a silver/carbon composite was synthesized, featuring monodisperse silver nanoparticles and a hierarchical mesoporous carbon framework. This composite exhibits robust surface activity, a well-defined pore structure, and superior mechanical properties. The catalyst achieves a catalytic yield nearing 90%, showcasing remarkable activity in terminal alkyne halogenation reactions. Its stability and recyclability are markedly enhanced; it retains 95% of its mass and remains unaltered in the reaction solvent for over 160 h after five cycles. This method simplifies the synthesis of terminal alkynes and their derivatives, rendering the process more environmentally benign and efficacious. Furthermore, it broadens the potential applications of Rhizoma Coptidis in synthetic chemistry and pioneers a novel approach for the synthesis of precious metal catalysts from renewable resources.

Mechanochemistry: Unravelling the Impact of Metal Leaching in Organic Synthesis.

Solvent-free techniques have gained considerable attention in recent years due to their environmental advantages and potential to enable chemical reactivities beyond the reach of traditional solution-based methods. Mechanochemistry has emerged as a groundbreaking approach to drive sustainable chemical processes. Despite its promise, some challenges still need to be explored, including the overlooked issue of material leaching during grinding, a phenomenon in which components from milling media or reaction vessels, such as stainless steel, unintentionally alter reaction outcomes. This study investigates the role of metal leaching in reducing arylnitrosamines by using a poorly soluble solid reagent, thiourea dioxide (TDO), focusing on stainless steel vessels. By comparing conventional mechanochemical methods with innovative solvent-free vibratory techniques, we assess the extent of metal contamination and its impact on reaction efficiency. These findings provide new insights into how material leaching influences chemical processes and offer valuable guidance for optimizing these forward-looking and green methodologies.

USING AI TO DEVELOP STUDENTS’ SCIENTIFIC SKILLS IN CHEMISTRY: FROM RESEARCH TO INNOVATION

The article discusses the use of artificial intelligence (AI) to develop students' scientific skills in chemistry, its role in promoting innovative research and technology. AI opens up new opportunities for students of chemical faculties, allowing them to effectively analyze large amounts of data, simulate chemical reactions and predict experimental results. The use of AI in research activities helps students develop critical thinking, research skills and promotes the creation of new chemical compounds and materials. The article also discusses prospects of AI in the development of new drugs, environmentally friendly technologies and sustainable chemical processes. Despite the many advantages, the introduction of AI into chemical education and research is associated with a number of challenges, including the need to train specialists. In conclusion, the importance of further introducing AI into chemical education is emphasized in order to improve the quality of scientific research and stimulate an innovative approach in chemistry

Exploring Nanomaterials for Enhanced Catalysis in Chemical Reactions

The study Nanotechnology has emerged as a ground-breaking frontier in the field of catalysis, offering promising avenues for revolutionizing chemical reactions. This abstract provides a concise overview of recent developments in harnessing nanomaterials to enhance catalytic processes. Nanomaterials, with their unique size-dependent properties and high surface area-to-volume ratios, have exhibited remarkable catalytic efficiency, selectivity, and stability. This abstract highlight key aspects of the research conducted to harness these advantages, including the synthesis and characterization of various nanomaterials such as nanoparticles, nanowires, and Nano sheets. These materials are tailored to optimize their catalytic performance by precisely controlling their size, shape, and composition. The discussion the diverse range of catalytic applications that benefit from nanomaterials, including green energy production, environmental remediation, and pharmaceutical synthesis. The enhanced catalytic activities facilitated by nanomaterials have the potential to reduce reaction times, lower energy consumption, and minimize waste products, contributing to more sustainable and efficient chemical processes and touches upon the challenges and future prospects of nanomaterial-based catalysis, emphasizing the need for further research to fully understand the underlying mechanisms and potential environmental and safety concerns. Collaborative efforts among chemists, material scientists, and engineers are essential to unlock the full potential of nanomaterials in catalysis and pave the way for innovative solutions to complex global challenges.

AshPhos Ligand: Facilitating Challenging Aminations in Five- and Six-Membered Heteroaryl Halides Using Cyclic Secondary and Bulky Amines.

Our newly developed AshPhos ligand represents a significant advancement in Buchwald-Hartwig aminations, overcoming many limitations of existing ligands. Created from affordable and accessible materials, AshPhos enhances catalytic performance, especially for extremely difficult substrates, by emphasizing the principles of ligand chelation and cooperativity. Its successful synthesis and application in catalytic aminations underscore its potential for use in the sustainable synthesis of compounds important to medicinal chemistry, materials, and energy. Further studies validated AshPhos's effectiveness in coupling challenging heteroaryl bromides and chlorides with various amines, including hindered amines and those with multiple heteroatoms. Slightly elevated temperatures were essential to avoid forming inactive species, ensuring consistent catalytic turnover. A control nuclear magnetic resonance spectroscopy study suggests the formation of catalytically dormant species or deligation of AshPhos from palladium at room temperature due to the coordination of multiple substrate molecules with the palladium species. Analyses showed cost-effectiveness of AshPhos, making it a significant advancement in catalytic amination for more efficient and sustainable chemical processes. The diverse substrate scope, covering challenging coupling partners and forming over 55 substrates in good-to-excellent yields, further demonstrated the efficiency of AshPhos.

Merger of Single-Atom Catalysis and Photothermal Catalysis for Future Chemical Production.

Photothermal catalysis is an emerging field with significant potential for sustainable chemical production processes. The merger of single-atom catalysts (SACs) and photothermal catalysis has garnered widespread attention for its ability to achieve precise bond activation and superior catalytic performance. This review provides a comprehensive overview of the recent progress of SACs in photothermal catalysis, focusing on their underlying mechanisms and applications. The dynamic structural evolution of SACs during photothermal processes is highlighted, and the current advancements and future perspectives in the design, screening, and scaling up of SACs for photothermal processes are discussed. This review aims to provide insights into their continued development in this rapidly evolving field.

Immobilized Eosin Y on Modified Silica Nanoparticles and their Applications in Organic Synthesis

AbstractThe development of novel photocatalytic systems is crucial for advancing sustainable chemical processes in organic synthesis. In this study, we report the preparation, characterization, and application of a heterogeneous photocatalyst based on Eosin Y (EY) covalently immobilized on silica nanoparticles (SNPs). The SNPs‐EY photocatalyst was thoroughly characterized using various techniques, including SEM, TEM, X‐ray diffraction, UV‐vis diffuse reflectance spectroscopy, solid‐state fluorescence spectroscopy, XPS, FT‐IR, TGA, and DLS. These analyses confirmed the successful immobilization of EY on SNPs and demonstrated the uniformity and favourable photophysical properties of the resulting hybrid material. The photocatalytic performance of SNPs‐EY was evaluated in a series of model reactions, including aza‐Henry reaction (cross‐dehydrogenative coupling), reduction of nitrocompounds, and photooxidation of dimethylanthracene. The reaction results demonstrated that SNPs‐EY is an effective and recyclable photocatalyst, offering yields comparable to or higher than those of homogeneous systems, while providing the advantages of easy separation and reuse. This study highlights the potential of SNPs‐EY as a versatile photocatalyst for various organic transformations, promoting the advancement of green and sustainable chemistry.

Methanol Activation: Strategies for Utilization of Methanol as C1 Building Block in Sustainable Organic Synthesis.

The development of efficient and sustainable chemical processes which use greener reagents and solvents, currently play an important role in current research. Methanol, a cheap and readily available resource from chemical industry, could be activated by transition metal catalysts. This review focuses in covering the recent five-years literature and provides a systematic summary of strategies for methanol activation and the use in organic chemistry. Based on these strategies, many new synthetic methods have been developed for methanol utilization as the C1 building block in methylation, hydromethylation, aminomethylation, formylation reactions, as well as the syntheses of urea derivatives and heterocycles. The achievements, synthetic applications, limitations, some advanced approaches, and future perspectives of the methanol activation methodologies have been described in this review.

Sustainable production of cyclohexanones through hydrodeoxygenation of lignin-derived phenolics over PdFe/HZSM-5 catalysts

Despite the crucial roles of cyclohexanones across various industrial sectors, notably in the production of nylon and plastics, their conventional production heavily relies on fossil resources. The exploration of highly efficient routes to convert renewable biomass into cyclohexanones holds promise for advancing sustainable chemical processes, especially with the growing concerns in energy and the environment. Herein, we report the direct conversion of lignin-derived phenolic compounds to cyclohexanones through hydrodeoxygenation using PdFe/HZSM-5 catalysts. The successful achieved conversion of guaiacol was up to 97.27%, with a greatest selectivity of 90.59% to cyclohexanone on PdFe1.5/HZSM-5. Characterization of the catalysts further revealed that bimetallic catalyst promoted the dispersion of PdFe on HZSM-5 and facilitated the interactions between PdFe because of electron transfer, which collectively facilitated surprising outcomes. This work offers a promising strategy for improving lignin valorization within the context of producing sustainable chemicals and industrial materials.

In situ growth of bismuth oxybromide/bismuth molybdate 2D/2D Z-scheme heterojunctions with rich interfacial oxygen vacancies for photocatalytic benzylic C(sp3)-H bond activation

The selective oxidation of toluene into valuable chemicals via photocatalytic C(sp3)-H bond activation represents a significant, yet challenging process. Here, the in situ construction of bismuth oxybromide/bismuth molybdate (BiOBr/Bi2MoO6) 2D/2D Z-scheme heterojunctions featuring interface-induced oxygen vacancies (OVs) is introduced. The optimized BiOBr/Bi2MoO6 sample has a remarkable yield rate of benzaldehyde at 2134.28 μmol g−1 h−1 under blue LED irradiation, surpassing the performance of BiOBr and Bi2MoO6 by 8.1 and 2.9 times, respectively. Insights from density functional theory (DFT) calculations, electron paramagnetic resonance (EPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies highlight the critical role of the Z-scheme electronic configuration and OVs in attaining the superior photocatalytic toluene conversion efficiency. This study advances the photocatalytic conversion of benzaldehyde within an OV-enhanced direct Z-scheme system, facilitating the activation of inert C(sp3)-H bonds, and contributes to the development of high-performance catalysts for sustainable chemical processes.

Integrating genetic algorithms and language models for enhanced enzyme design.

Enzymes are molecular machines optimized by nature to allow otherwise impossible chemical processes to occur. Their design is a challenging task due to the complexity of the protein space and the intricate relationships between sequence, structure, and function. Recently, large language models (LLMs) have emerged as powerful tools for modeling and analyzing biological sequences, but their application to protein design is limited by the high cardinality of the protein space. This study introduces a framework that combines LLMs with genetic algorithms (GAs) to optimize enzymes. LLMs are trained on a large dataset of protein sequences to learn relationships between amino acid residues linked to structure and function. This knowledge is then leveraged by GAs to efficiently search for sequences with improved catalytic performance. We focused on two optimization tasks: improving the feasibility of biochemical reactions and increasing their turnover rate. Systematic evaluations on 105 biocatalytic reactions demonstrated that the LLM-GA framework generated mutants outperforming the wild-type enzymes in terms of feasibility in 90% of the instances. Further in-depth evaluation of seven reactions reveals the power of this methodology to make "the best of both worlds" and create mutants with structural features and flexibility comparable with the wild types. Our approach advances the state-of-the-art computational design of biocatalysts, ultimately opening opportunities for more sustainable chemical processes.

Suppressing Electrolyte Flooding in CO2 Electrolyzers Via Surface-Functionalized Microporous Layers

The advancement of carbon dioxide (CO2) electrolyzers employing a three-compartment configuration represents a significant stride towards sustainable chemical processes. Central to this approach is the necessity for an effective supply of gaseous reactants and the suppression of competing hydrogen evolution reactions (HER) to ensure efficient and selective chemical production. A key component within this setup is the porous gas diffusion electrode (GDE), mainly responsible for optimizing CO2 diffusion through the gas diffusion layer (GDL) to the catholyte compartment. GDEs, located in between the catholyte chamber and the gas flow field, are indispensable for industrial applications due to their ability to achieve high current densities by ensuring a sufficient supply of CO2 to the reaction sites. However, conventional GDEs with carbon substrates have encountered challenges such as electrolyte flooding, leading to decreased efficiency and hindering practical application. The efficacy of CO2 diffusion is further hindered by pressure imbalances across the GDL, resulting in undesirable crossflow phenomena. Catholyte crossover into the CO2 flow field triggers flooding, adversely affecting electrochemical efficiency, blocking CO2 transport pathways, causing liquid product loss, and damaging the cell. To address these issues, precise surface engineering techniques are necessary to impart hydrophobicity onto microporous layers (MPLs). Chemical grafting mechanisms, affixing functionalized silane group agents onto MPLs, enable robust covalent bonds and minimize surface tension, enhancing resistance to electrolyte flooding and facilitating effective CO2 transport. Here we present a single-step treatment approach under room temperature, offering a more viable approach for optimizing the local microenvironment by suppressing catholyte crossover phenomena. , the impact of silane-treated GDLs on CO2 electrolyzers is analyzed, highlighting their role in flood prevention, enhancing cell durability, and achieving high current densities. This research underscores the pivotal role of surface modification techniques in advancing electrochemical systems tailored for sustainable CO2 conversion processes, thus contributing to a greener and more sustainable future.

(Invited) Engineering Microenvironments for Photo-Electrochemical Reduction of Carbon Dioxide

Due to the escalating crisis of global warming, carbon dioxide (CO2) conversion has garnered significant attention as a pivotal technology for sustainable energy and chemical processes. However, the challenge lies in its nature as a strong endothermic reaction with substantial activation energy, thus requiring extensive energy input. Therefore, integration with renewable energy sources becomes imperative. In this regard, Photo- and electrochemical CO2 reduction (CO2R) presents promising avenues for converting CO2 with water (H2O) using electricity derived from renewable sources, thereby producing various chemicals and fuels. However, the abundance of H2O in the catalytic microenvironment promotes the competing evolution of hydrogen (H2), leading to diminished energy efficiency and selectivity toward CO2R products. Additionally, another challenge is to selectively produce valuable multicarbon products (C2+ products), including C2H4, C2H5OH, and C3H7OH, which hold higher market value and greater market volume compared to single-carbon products (C1 products) like HCOOH, CO, and CH4. Among various CO2R catalysts, Copper (Cu)-based materials have emerged as prominent candidates due to their capability to yield C2+ products with considerable activity and selectivity. Recent studies suggest that catalytic microenvironments significantly influence C2+ production on Cu-based catalysts. Hence, this presentation aims to elucidate the impact of these microenvironments near Cu catalysts and explore how this knowledge can be effectively applied to design a photocathode for the photo-electrochemical reduction of CO2, thereby enhancing the production of C2+ products.

Novel sustainable design of pressure-swing distillation coupled with natural decanting and Organic Rankine Cycle for separating n-propanol/benzene/water mixture

The separation of ternary azeotropic mixtures is a common challenge in the chemical industry due to the unique properties of azeotropes. This phenomenon complicates the separation processes, as traditional distillation methods may not effectively separate the components. The present work introduces a novel pressure-swing distillation (NPSD) process integrated with natural decanting for the effective separation of an n-propanol/benzene/water mixture. By exploiting the liquid–liquid envelope characteristics of the mixture, phase separation prior to distillation significantly enhances the separation efficiency. The NPSD process was optimised using the NSGA-II, addressing economic, environmental, and energetic objectives. Key findings reveal that the implementation of decanting allows the NPSD process to operate without substantial pressure adjustments, thereby facilitating fine separation more efficiently than conventional pressure-swing distillation designs. The proposed NPSD process can achieve up to 25.76 % savings in TAC while reducing CO2 emissions and improving energy efficiency. Furthermore, the integration of mechanical vapour recompression heat pump and Organic Rankine Cycle systems enhances energy saving, resulting in a TAC reduction of up to 31 % and a decrease in CO2 emissions of up to 38 % compared to existing energy-efficient designs. These findings highlight the potential of the NPSD-MVR-ORC system for sustainable chemical separation processes.

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

AbstractCarbon 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.

Multi-Stage Stochastic Programming Under Endogenous Uncertainty of Integrated Sustainable Chemical Process Design and Expansion Planning

Multi-Stage Stochastic Programming Under Endogenous Uncertainty of Integrated Sustainable Chemical Process Design and Expansion Planning

Quantum Molecular Dynamics Approach to Understanding Interactions in Betaine Chloride and Amino Acid Natural Deep Eutectic Solvents.

The unique properties and versatile applications of natural deep eutectic solvents (NaDES) have sparked significant interest in the field of green chemistry. Comprised of natural components that form liquids at room temperature through strong noncovalent electrostatic interaction, these solvents are cost-effective, nontoxic, and versatile. Betaine chloride-based NaDES, in particular, have shown promise in biocatalysis and sugar extraction due to their excellent properties. Despite their potential, the complex nature of these solvents, characterized by intense hydrogen bonding and proton transfer processes, poses significant challenges. This study employs quantum molecular dynamics (ab initio MD-AIMD) to explore the intricate NaDES-microstructure formed from betaine chloride and amino acids (arginine, histidine, lysine). Our findings highlight the dynamic nature of proton transfers within these solvents, demonstrating rapid and extensive hydrogen bonding interactions. The Van Hove correlation functions reveal that proton transfers are highly mobile, facilitating the formation and breaking of covalent hydrogen bonds. This dynamic behavior is further corroborated by the radial distribution functions, which indicate significant proton exchange between amino acids and betaine cations. Chloride anions play a crucial role in maintaining the structural integrity of NaDES through strong interactions with proton donors. These findings advance our understanding of these eutectic solvents and their potential applications in sustainable chemical processes.

Graphene-based Nanomaterials As Catalysts for the Synthesis of Medicinally Privileged Heterocycles: Importance and Outlook

: Catalysis is an integral part of sustainable and green chemical processes. During the last two decades, the wonder 2D carbon material with honeycomb structure, graphene, and other functionalized graphenes have emerged as extremely versatile and robust nanomaterials in heterogeneous catalysis. The incredible catalytic efficacy of such carbon nanomaterials relies on their unique physicochemical properties, including large surface area, diverse catalytic active sites, multiple chemical functionalities, tunable electron density, synergistic effect, etc., making them noteworthy as metal-free catalysts and catalytic supports. : The article presents an overview of the catalytic applications of various graphene-based nanomaterials (GBNs), either metal-free or embedded with metal/metal oxide NPs, in synthesizing medicinally privileged heterocyclic compounds. It also summarizes the general methodologies for preparing graphene and various GBNs, their chemical structures, characterization techniques, and discussions on the potential active sites that are responsible for wider catalytic activity. Overall discussions unequivocally establish a promising paradigm for uncovering more innovative graphene-based materials and their subsequent applications in diverse fields, including heterogeneous catalysis.