Hasil untuk "Chemical technology"

N. Turner

S. McIntosh, R. Gorte

Hua Zhao, Shuqian Xia, Pei-sheng Ma

R. Kothari, D. Buddhi, R. Sawhney

T. Noël, Yiran Cao, G. Laudadio

Conspectus In the past decade, research into continuous-flow chemistry has gained a lot of traction among researchers in both academia and industry. Especially, microreactors have received a plethora of attention due to the increased mass and heat transfer characteristics, the possibility to increase process safety, and the potential to implement automation protocols and process analytical technology. Taking advantage of these aspects, chemists and chemical engineers have capitalized on expanding the chemical space available to synthetic organic chemists using this technology. Electrochemistry has recently witnessed a renaissance in research interests as it provides chemists unique and tunable synthetic opportunities to carry out redox chemistry using electrons as traceless reagents, thus effectively avoiding the use of hazardous and toxic reductants and oxidants. The popularity of electrochemistry stems also from the potential to harvest sustainable electricity, derived from solar and wind energy. Hence, the electrification of the chemical industry offers an opportunity to locally produce commodity chemicals, effectively reducing inefficiencies with regard to transportation and storage of hazardous chemicals. The combination of flow technology and electrochemistry provides practitioners with great control over the reaction conditions, effectively improving the reproducibility of electrochemistry. However, carrying out electrochemical reactions in flow is more complicated than just pumping the chemicals through a narrow-gap electrolytic cell. Understanding the engineering principles behind the observations can help researchers to exploit the full potential of the technology. Thus, the prime objective of this Account is to provide readers with an overview of the underlying engineering aspects which are associated with continuous-flow electrochemistry. This includes a discussion of relevant mass and heat transport phenomena encountered in electrochemical flow reactors. Next, we discuss the possibility to integrate several reaction steps in a single streamlined process and the potential to carry out challenging multiphase electrochemical transformations in flow. Due to the high control over mass and heat transfer, electrochemical reactions can be carried out with great precision and reproducibility which provide opportunities to enhance and tune the reaction selectivity. Finally, we detail on the scale-up potential of flow electrochemistry and the importance of small interelectrode gaps on pilot and industrial-scale electrochemical processes. Each principle has been illustrated with a relevant organic synthetic example. In general, we have aimed to describe the underlying engineering principles in simple words and with a minimum of equations to attract and engage readers from both a synthetic organic chemistry and a chemical engineering background. Hence, we anticipate that this Account will serve as a useful guide through the fascinating world of flow electrochemistry.

S. Pang

Biomass has been recognised as a promising resource for future energy and fuels. The biomass, originated from plants, is renewable and application of its derived energy and fuels is close to carbon-neutral by considering that the growing plants absorb CO2 for photosynthesis. However, the complex physical structure and chemical composition of the biomass significantly hinder its conversion to gaseous and liquid fuels. This paper reviews recent advances in biomass thermochemical conversion technologies for energy, liquid fuels and chemicals. Combustion process produces heat or heat and power from the biomass through oxidation reactions; however, this is a mature technology and has been successfully applied in industry. Therefore, this review will focus on the remaining three thermochemical processes, namely biomass pyrolysis, biomass thermal liquefaction and biomass gasification. For biomass pyrolysis, biomass pretreatment and application of catalysts can simplify the bio-oil composition and retain high yield. In biomass liquefaction, application of appropriate solvents and catalysts improves the liquid product quality and yield. Gaseous product from biomass gasification is relatively simple and can be further processed for useful products. Dual fluidised bed (DFB) gasification technology using steam as gasification agent provides an opportunity for achieving high hydrogen content and CO2 capture with application of appropriate catalytic bed materials. In addition, multi-staged gasification technology, and integrated biomass pyrolysis and gasification as well as gasification for poly-generation have attracted increasing attention.

P. Bautista, Á. F. Mohedano, J. Casas et al.

E. Maginn, Richard A. Messerly, Daniel J. Carlson et al.

1Department of Chemical and Biomolecular Engineering, The University of Notre Dame; 2Thermodynamics Research Center, National Institute of Standards and Technology; 3Chemical Engineering Department, Brigham Young University; 4Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health; 5Department of Chemical and Biomolecular Engineering, The University of Akron

L. Candish, Karl D. Collins, G. Cook et al.

In the pursuit of new pharmaceuticals and agrochemicals, chemists in the life science industry require access to mild and robust synthetic methodologies to systematically modify chemical structures, explore novel chemical space, and enable efficient synthesis. In this context, photocatalysis has emerged as a powerful technology for the synthesis of complex and often highly functionalized molecules. This Review aims to summarize the published contributions to the field from the life science industry, including research from industrial-academic partnerships. An overview of the synthetic methodologies developed and strategic applications in chemical synthesis, including peptide functionalization, isotope labeling, and both DNA-encoded and traditional library synthesis, is provided, along with a summary of the state-of-the-art in photoreactor technology and the effective upscaling of photocatalytic reactions.

E. Cho, L. Trinh, Younho Song et al.

Dwindling petroleum resources and increasing environmental concerns have stimulated the production of platform chemicals via biochemical processes through the use of renewable carbon sources. Various types of biomass wastes, which are biodegradable and vastly underutilized, are generated worldwide in huge quantities. They contain diverse chemical constituents, which may serve as starting points for the manufacture of a wide range of valuable bio-derived platform chemicals, intermediates, or end products via different conversion pathways. The valorization of inexpensive, abundantly available, and renewable biomass waste could provide significant benefits in response to increasing fossil fuel demands and manufacturing costs, as well as emerging environmental concerns. This review explores the potential for the use of available biomass waste to produce important chemicals, such as monosaccharides, oligosaccharides, biofuels, bioactive molecules, nanocellulose, and lignin, with a focus on commercially viable technologies.

A. Varela, W. Ju, A. Bagger et al.

The electrochemical CO2 reduction reaction (CO2RR) is a promising technology for converting waste CO2 into chemicals which could be used as feedstock for the chemical industry or as synthetic fuels...

H. Ruiz, M. Conrad, Shaoni Sun et al.

Different pretreatments strategies have been developed over the years mainly to enhance enzymatic cellulose degradation. In the new biorefinery era, a more holistic view on pretreatment is required to secure optimal use of the whole biomass. Hydrothermal pretreatment technology is regarded as very promising for lignocellulose biomass fractionation biorefinery and to be implemented at the industrial scale for biorefineries of second generation and circular bioeconomy, since it does not require no chemical inputs other than liquid water or steam and heat. This review focuses on the fundamentals of hydrothermal pretreatment, structure changes of biomass during this pretreatment, multiproduct strategies in terms of biorefinery, reactor technology and engineering aspects from batch to continuous operation. The treatise includes a case study of hydrothermal biomass pretreatment at pilot plant scale and integrated process design.

Harifara Rabemanolontsoa, S. Saka

Jianlong Wang, S. Zhuang

Rigoberto Advincula, Jihua Chen

Chemical reaction engineering is key to industrial might and sustainable chemistry. This will be enabled using smart, efficient catalysts or catalysis ecosystems. This is possible with advanced artificial intelligence and machine learning (AI/ML) workflows that need to be employed as agentic AI projects. The fundamentals of catalysis need to be emphasized. A strong focus on catalyst design, mechanistic studies, reaction engineering, and scale-up must use ML-driven workflows, along with high-throughput experimentation (HTE) and an autonomous, self-driving laboratory (SDL). Laboratory experience and data-driven approaches are valuable when working together to accelerate this development. Parametrize and create a virtuous circle for data-driven discovery across heterogeneous, homogeneous, and biocatalysts to enable utility in many chemical process industries as agentic AI tasks. This article builds the case for discovery science in catalysis and continuous improvement in chemical reaction engineering with this new ecosystem.

Qiguang Liu, Yanyun Li, Zhenghao Wu et al.

ABSTRACT In the era of artificial intelligence (AI)‐driven high‐performance computing, phase change materials (PCMs) are critical for high‐flux thermal management. PCMs are evolving toward high enthalpy, low interfacial thermal resistance (ITR), and high reliability. Herein, we design double‐brush phase‐change polymer (PVBS‐TMCn) crosslinked by B─O─B and Si─O─B dynamic bonds, characterized by the ultra‐fast relaxation time of 0.8 s under 80°C and closed‐loop cycling. This architecture enhances the content of phase‐change units for elevated theoretical enthalpy, while inherent multiple dynamic bonds and ultra‐low entanglement minimize enthalpy loss, resulting in a record enthalpy of 240.7 J·g−1. Furthermore, a composite of flexibility PVBS‐TMC14/24 and graphene foam films (PVBS‐TMC/GF) is fabricated as thermal interface materials using a stacking‐cutting strategy, which self‐adaptively modulates low‐ITR in response to temperature, owing to phase transition properties, ultra‐low modulus, and adaptive filling capability of dynamic polymer matrix. PVBS‐TMC/GF significantly generates better thermal management efficiency compared to commercial products. The topology design of double‐brush polymer dynamic networks and interfacial contact mechanisms provide fundamental insights for developing phase‐change adaptive materials and advancing thermal management.

J. Gaitzsch, Xinshu Huang, B. Voit

R. B. Eldridge

Matthias Kellner, Jacob B. Holmes, Ruben Rodriguez-Madrid et al.

Nuclear Magnetic Resonance (NMR) chemical shifts are powerful probes of local atomic and electronic structure that can be used to resolve the structures of powdered or amorphous molecular solids. Chemical shift driven structure elucidation depends critically on accurate and fast predictions of chemical shieldings, and machine learning (ML) models for shielding predictions are increasingly used as scalable and efficient surrogates for demanding ab initio calculations. However, the prediction accuracies of current ML models still lag behind those of the DFT reference methods they approximate, especially for nuclei such as $^{13}$C and $^{15}$N. Here, we introduce ShiftML3.0, a deep-learning model that improves the accuracy of predictions of isotropic chemical shieldings in molecular solids, and does so while also predicting the full shielding tensor. On experimental benchmark sets, we find root-mean-squared errors with respect to experiment for ShiftML3.0 that approach those of DFT reference calculations, with RMSEs of 0.53 ppm for $^{1}$H, 2.4 ppm for $^{13}$C, and 7.2 ppm for $^{15}$N, compared to DFT values of 0.49 ppm, 2.3 ppm, and 5.8 ppm, respectively.

Ha Eun Kang, Seong-Do Kim, Young Soo Yoon et al.

Nickel-rich layered oxide cathodes, typified by compositions such as LiNi₁₋ₓ₋ᵧCoₓMnᵧO₂ (NCM) have garnered significant attention as high-energy-density candidates for next-generation lithium-ion batteries. However, their widespread deployment is hindered by a confluence of structural degradation, surface instability, and poor interfacial compatibility under high voltage cycling. To address these multifaceted limitations, this review comprehensively examines recent advances in surface coating and bulk doping strategies, which have emerged as pivotal approaches for enhancing the electrochemical stability and longevity of Ni-rich cathodes. Surface coatings including oxides, phosphates, and fluorides have been shown to effectively mitigate electrolyte-induced parasitic reactions and reinforce cathode–electrolyte interfaces. Simultaneously, elemental doping at transition-metal, lithium, and oxygen sites offer promising pathways to suppress cation disorder, stabilize layered frameworks, and facilitate Li⁺ transport. Emphasis is placed on site-specific doping mechanisms, the role of multi-site (co-)doping, and their synergistic interplay with surface modification layers. By synthesizing recent findings, this review delineates how the judicious integration of coating and doping techniques can enable the rational design of Ni-rich cathodes with enhanced structural integrity, rate capability, and cycle life.