Reaction Chemistry & Engineering最新文献

Chemical synthesis is an essential step in the drug substance manufacturing process as it affects both the yield and purity of the product. This paper focuses on the use of reaction network kinetic modeling to design a high yielding continuous synthesis of an anti-epileptic drug substance carbamazepine (CBZ) that minimizes impurity formation. The reactor system was constructed with two continuously stirred tank reactors (CSTRs) in series. The synthesis was carried out by reacting potassium cyanate (KOCN) with iminostilbene (ISB) in acetic acid at concentration levels of ISB above the room temperature solubility to improve reaction kinetics and yield. The outlet of the synthesis reactor was followed by an integrated continuous precipitation step to obtain CBZ precipitate. The reaction system itself was studied first in batch reactions to determine kinetic parameters, including reactant orders, of four primary reactions. Using the reactant order kinetic parameters obtained by the batch kinetic study, causes of discrepancies between the batch and continuous systems were theorized and mitigated by adjusting (1) the KOCN addition method, (2) the KOCN addition split ratio (between the 2 CSTRs), and (3) the ISB dissolution method (above room temperature solubility). After synthesis optimization was completed, a single continuous cooling crystallization in ethanol was performed on the CBZ precipitate to obtain the target polymorphic form (CBZ form III) within the impurity limits of USP. Overall, this paper supports the design and optimization of a continuous drug substance synthesis process of CBZ by demonstrating the capability of reaction network modeling for maximizing yield and minimizing impurities.

This study evaluated the effect of incorporating a rare-earth-based fluorescent powder (REFP) on the mechanical properties and thermal stability of polyvinyl chloride (PVC). A systematic investigation was conducted to determine the optimal loading concentration of fluorescent powder in polyvinyl chloride (PVC) materials, to evaluate its effect on the materials' mechanical properties and thermal stability. A rare-earth-based fluorescent powder (REFP) consisting of Eu³⁺-doped LaP₃O₉ was synthesised using a coprecipitation method. This REFP was then utilised as both a functional filler and a photothermal stabiliser. The REFP was then incorporated into the PVC matrix via thermal processing at various mass concentrations (1%, 2%, 3%, 4%, 5% and 6%). The resulting PVC composites were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy (FS). Key thermal stability parameters, including thermal stability time, decomposition temperature and volatile content, were also assessed. The findings demonstrated that the inclusion of REFP significantly enhanced the thermal stability of PVC. Specifically, at 3 wt% REFP, the thermal stability time increased by 16%, and the decomposition temperature reached a peak of 158.6 °C. Furthermore, the emission of HCl, a degradation by-product, was effectively suppressed. In addition to the improved thermal properties, the mechanical performance of the PVC fluorescent tubes was also markedly enhanced. At the optimal REFP content of 3 wt%, the elongation at break was 156%, the Vicat softening temperature was 83.6 °C, and the tensile strength was 52.1 MPa. Compared to pristine PVC, these values represent increases of 20%, 4.1 °C and 6.6 MPa, respectively. Overall, incorporating REFP into PVC imparts dual functionality, significantly enhancing the material's mechanical and thermal properties while enabling it to absorb ultraviolet radiation and re-emit it as visible light. This photofunctional PVC composite shows great potential for use in in situ industrial early warning systems.

Transport and kinetics phenomena such as advection, dispersion and reaction play a key role in determining the performance and safety of chemical reactors. While advection–dispersion–reaction (ADR) processes have been analyzed in the past for single-stage chemical reactors, this work presents a solution for the ADR equation in a multistage chemical reactor in which each stage may have distinct transport and kinetic properties. A series solution for the concentration distribution is written, and the coefficients are determined using boundary and interface conditions. A quasi-orthogonality relationship between eigenfunctions of the problem is derived and used for completing the derivation of the solution. It is shown that, except at very early times, the use of just a few eigenvalues is sufficient for reasonable accuracy. Trade-offs related to computational time and accuracy for a one-term approximation are analyzed. Under special conditions, results from the general multistage analysis are shown to correctly reduce to results for a single-stage reactor, with good agreement with past work. Based on the theoretical model derived here, the evolution of the concentration field in the multistage reactor over time is analyzed. The impact of key non-dimensional parameters on the concentration field is analyzed in detail. It is shown that the species concentration in the reactor and the reactor time constant both depend strongly on the reaction rate constant, while there is only a weak dependence on the Péclet number. The theoretical derivation presented here offers a significant generalization of ADR analysis for chemical reactors, making it possible to analyze a multistage chemical reactor. In addition to this theoretical novelty, results from this work may also help improve the design and optimization of practical multistage chemical reactors.

A lignin-first biorefinery based on oxidative fractionation of lignocellulose is presented for the first time. Red oak was successfully delignified through alkaline oxidation yielding carbohydrate pulp and phenolic monomer-rich lignin oil. Process conditions for optimizing phenolic monomer yield, glucan retention in the pulp, and delignification were explored. The effect of temperature, oxygen partial pressure, time, catalyst, and sodium hydroxide concentration were assessed using a response surface statistical method. Two different operating windows were proposed to get the optimum results. Temperature and time were the most significant explanatory variables for all the response models. The presence of CuSO₄ catalyst was of slight significance in the production of monomers if reaction time was short. Under optimum reaction conditions, the lignin oil consisted of around 40% phenolic monomers (mainly syringaldehyde and vanillin). The structural features of the lignin oil were further analyzed by GC/MS, GPC, and 2D HSQC NMR techniques. The isolated carbohydrate pulp retained approximately 97 wt% of the cellulose under optimum reaction conditions. Powder X-ray diffraction of the isolated carbohydrate pulp showed that the cellulose was of crystalline structure, indicating its potential for paper production. Enzymatic hydrolysis of the carbohydrate pulp converted 85% of the cellulose to glucose within 120 h, illustrating the potential of cellulosic ethanol production via this lignin-first strategy.

The most important characteristics of a perfect catalyst comprise simple design, good activity, excellent stability, easy recovery from the reaction mixture, recyclability, and the ability to scale up easily. The development of nanocatalysts using a biocompatible, phytochemical-assisted method for organic transformation and bioactivity studies has been relatively less explored. In this regard, we developed copper nanoparticles (Cu NPs) embedded on magnetite Fe₃O₄ as support, employing peel extract of Ananas comosus (ACPE) as a stabilizing, reducing, and capping agent (Fe₃O₄@ACPE@Cu). ICP-OES demonstrated 9.26% (w/w) Cu loading on the magnetite Fe₃O₄ support, with irregular morphology and well-dispersed elements, as confirmed by HR-TEM and HAADF analyses. The developed Fe₃O₄@ACPE@Cu nanocatalyst demonstrated impressive productivity in synthesizing various tetrazoles, yielding 96% for the model substrate. Additionally, a yield of 95% was observed for the model substrate used for the synthesis of 1-substituted benzimidazole. Furthermore, the nanocatalyst demonstrated notable recyclability and remained effective for up to six consecutive cycles with no significant loss in catalytic activity in the subsequent cycle. In addition, both the Fe₃O₄ support and the Fe₃O₄@ACPE@Cu nanocatalyst showed promising results in a colon cancer study, with excellent biocompatibility. Thus, the developed strategy integrates sustainable innovation and offers revolutionary solutions for organic transformations and medicinal chemistry.

The electrochemical reduction of furfural to 2-methylfuran (MF) offers a green and efficient route for producing high-value biofuels and chemicals from biomass. This review critically examines the recent progress in the catalyst development, mechanistic understanding, and interface engineering strategies that enhance the selectivity for MF while mitigating side reactions such as the hydrogen evolution reaction (HER). Key factors including electrode materials, electrolyte pH, applied potential, and adsorption configuration are explored in detail. Although advances in operando characterization and theoretical modeling have begun to reveal the active sites and reaction pathways, challenges persist in achieving high selectivity and scalability. We identify the current limitations, such as the competing reactions, unclear active sites, and limited electrode diversity, and propose targeted solutions including dynamic interface tuning, molecular modifiers, and rational catalyst design. This review highlights the potential of electrocatalytic conversion of furfural to MF as a sustainable platform for future green chemical manufacturing.

We would like to take this opportunity to thank all of Reaction Chemistry & Engineering's reviewers for helping to preserve quality and integrity in chemical science literature. We would also like to highlight the Outstanding Reviewers for Reaction Chemistry & Engineering in 2024.

Prussian blue analogs (PBAs) are considered as promising cathode materials for sodium-ion batteries due to their wide framework structures for the transportation of sodium ions. However, conventional Prussian blue analogs (PBAs) often suffer from structural instability and limited capacity due to inherent defects and lattice water in the structure. Herein, manganese-doped Prussian blue analogs (FeMn-PBAs) were synthesized via a modified co-precipitation method to address the issues of structural instability and low sodium storage capacity in PBAs, thereby exploring their potential as high-performance cathode materials for sodium-ion batteries (SIBs). The experimental results revealed that FeMn-PB exhibited a high initial capacity of 121.6 mAh g⁻¹ and outstanding cycling stability, retaining 96.6% of its capacity after 100 cycles of tests at a current density of 170 mA g⁻¹. The improved performance is attributed to reduced lattice water, and enhanced Na⁺ diffusion kinetics. This work provides new insights into the modification of PBAs and highlights the promising application of manganese ion doping in advancing energy storage technologies.

Ceramic composites, especially nano-metal oxides, have proven to be promising materials for various technical applications due to their excellent surface properties. In this study, the Zn–Cu–Ni oxide nanocomposites were successfully synthesized by the co-precipitation method in four different compositions (NiO in percentages of 0, 10, 20 and 30%). The products were coated on stainless steel 316LC (SS316LC) by electrophoretic deposition (EPD) at 70, 80, 90 and 100 V for in 4–10 min. FTIR, XRD, optical microscopy, FESEM, wear and corrosion (polarization and EIS) analyzes were used to investigate the products. The coating parameters played an important role in determining the surface properties of the coatings on SS316LC. Longer coating time and lower voltage resulted in smoother coatings with improved corrosion resistance. The highest corrosion resistance was at 80 V-6 min. These results underlined the potential of ceramic nanocomposite coatings of Zn–Cu–Ni oxide to improve the surface properties of steel in technical applications.

Chlorogenic acid, a bioactive compound with significant pharmacological and industrial value, is predominantly sourced through conventional extraction methods that exhibit resource dependency, high cost, inefficiencies, and environmental concerns. To address the dual challenges of surging market demand and environmental preservation, synthetic biology-driven microbial fermentation emerges as a pivotal sustainable strategy to overcome traditional production bottlenecks. Through rational design of metabolic networks, development of modular co-culture systems, and integration of intelligent regulation tools, efficient, resource-conserving, and environmentally benign chlorogenic acid production can be achieved. This study provides an innovative paradigm for the biomanufacturing of high-value chemicals.