Reaction Chemistry & Engineering最新文献

A novel, efficient method has been developed for the synthesis of bicyclic thiazolidine hydantoin, a key intermediate in the chiral pool-based synthesis of D-biotin. N-Benzyl-1H-imidazole-1-carbaldehyde, which is cost-effective and readily accessible, was used to replace the traditionally employed, flammable, and expensive benzyl isocyanate. Upon undergoing a cyclization reaction with (R)-2-phenylthiazolidine-4-carboxylic acid, it successfully constructed the bicyclic structure of the target compound. By optimizing reaction solvents, feeding methods, dosage, reaction temperature, and time, the most suitable reaction conditions were identified. This process was achieved without the need for any catalysts, resulting in an 85% yield. Meanwhile, two by-products were monitored during the reaction, and their formation mechanisms were investigated. Further studies demonstrated that this method exhibits excellent functional group tolerance, enabling the incorporation of a broad range of substrates. This study presents a scalable and efficient approach for the synthesis of bicyclic thiazolidine hydantoin, offering significant advantages in terms of safety, cost-effectiveness, and industrial applicability. Additionally, it establishes a preliminary foundation for the industrialization of the D-biotin chiral pool-based synthetic route.

Microfluidics is a very attractive discipline for implementing more versatile high-throughput screening methods to improve enzymes. However, state-of-the-art microfluidics set-ups are mainly devoted to screening enzymes in solution, while screening of enzyme immobilisation protocols using microfluidics is scarce. In this work, we develop a versatile wall-coated microreactor (WCμR) plate for transaminase screening, integrating up to 32 poly(methyl methacrylate) (PMMA) WCμR functionalised with different metal chelates. The device is validated by screening His-tagged and His-clustered amine transaminase (ATA) variants that result in different orientations, evaluating a total of 30 unique biocatalyst-functionalisation combinations for activity, stability, and immobilisation efficiency. In batch mode reactions, H3A, H2A, and H4 ATA variants from Pseudomonas fluorescens, Chromobacterium violaceum, and Haelomonas elongata, respectively, immobilised on copper-chelates exhibit the highest scores based on fluorometer assays. This WCμR plate can be easily integrated with optical microscopes for spatiotemporal assays. Alternatively, these WCμRs are readily adapted for continuous biotransformation operating as flow microreactors. This capability is tested with a His-tagged ATA immobilised on the microchannels to continuously aminate 5-hydroxymethyl furfural, achieving a specific productivity of 0.49 mol_HMFA mol_ATA⁻¹ s⁻¹ and a total turnover number of 9 × 10³, with a maximum space–time yield (STY) of 0.077 g L⁻¹ d⁻¹. This study highlights the potential of WCμRs for high-throughput enzyme screening and continuous biocatalysis, offering precise control over reaction conditions.

The growing accumulation of non-biodegradable plastics worldwide is causing environmental havoc that needs to be effectively addressed immediately by providing a sustainable solution. In this regard, a Cu–PTA metal–organic framework (MOF) was synthesized from discarded PET bottles and waste copper (Cu) metal derived from CHNS analyzer oxidation tubes and utilized to remove Congo red (CR) from aqueous solutions. The synthesized Cu–PTA–MOF was analyzed using various characterizations to reveal their crystal lattices and compositional and morphological features. Subsequently, the efficacy of the synthesized MOF in the adsorption of Congo red dye (20 mg L⁻¹) was investigated. The optimized conditions were determined to be pH 7, an adsorbent dosage of 10 mg, and a contact time of 60 min, which resulted in a 95% removal efficiency and demonstrated the potential of the MOF for adsorption applications. Furthermore, the data were fitted to different isotherm models, which correlated with the Redlich–Peterson adsorption model, indicating monolayer and multilayer adsorption. The kinetic data also fitted well with the pseudo-second-order kinetic model, while thermodynamic analysis revealed that the adsorption of Congo red was exothermic, spontaneous and physisorption process. This study adds to the larger goal of promoting resilience and long-term viability in materials science and environmental engineering through waste valorization, as well as environmental remediation for adsorption applications.

Polyethylene terephthalate (PET) is one of the most widely used plastics, yet its poor biodegradability has led to severe environmental accumulation. Chemical recycling via glycolysis offers a viable pathway to depolymerize PET into bis(2-hydroxyethyl) terephthalate (BHET), enabling closed-loop production of virgin-grade PET and its derivatives. In recent years, heterogeneous metal catalysts have emerged as highly efficient systems for PET glycolysis, offering advantages such as enhanced activity, selectivity, ease of separation, and reusability. This review critically examines recent advancements in heterogeneous metal-based catalysts, including transition metal oxides, mixed-metal oxides, supported nanoparticles, magnetic catalysts, and bifunctional acid–base materials. The influence of catalyst morphology, surface chemistry, and reaction parameters is discussed in detail alongside mechanistic insights. Challenges such as feedstock impurities, catalyst deactivation, and scale-up limitations are highlighted. By bridging materials innovation with process optimization, heterogeneous metal-catalyzed glycolysis presents a sustainable and scalable approach for transforming PET waste into a valuable monomer, aligning with circular economy and environmental sustainability goals.

The formation of C–C bonds through automated synthesis platforms aims to accelerate the preparation of molecules, simplify operational processes, and reduce the human time involved in the preparation of molecules. Here, we report different C–C bond formation reactions using a low-cost automated synthesis platform that aims to make automated organic synthesis more affordable. The platform, MIK-I, is capable of performing reactions widely used in organic chemistry, such as Claisen–Schmidt condensations, Suzuki–Miyaura couplings, Knoevenagel condensations, and Baylis–Hillman reactions, with similar yields obtained manually. This result highlights the platform's potential to operate under a basic scheme of synthesis to generate molecules of interest in organic chemistry.

Crude oil emulsions are challenging to break due to their complex and variable composition. While high-performance demulsifiers exist, many conventional systems still face limitations such as poor stability under harsh conditions or insufficient separation efficiency for specific emulsion types. It is thus essential to develop new demulsifiers that combine high salt resistance with effective destabilization capability. Carbon materials, known for their strong adsorption capacity and chemical stability, can efficiently capture emulsified droplets, enabling significantly enhanced demulsification performance even under harsh conditions. The integration of TiO₂–carbon heterostructures with fluorinated polyether grafting into magnetic demulsifiers represents a previously unreported strategy. Building on this background, our research innovatively modified the magnetic substrate Fe₃O₄ by incorporating TiO₂ and three types of carbon materials (carbon nanospheres, graphene oxide, and carbon nanotubes). Through a sol–gel approach, fluorinated polyether chains were covalently grafted onto the surface of modified Fe₃O₄ nanoparticles, leading to the successful synthesis of three novel magnetic composite demulsifiers: Fe₃O₄@Ti/C–F, Fe₃O₄@Ti/G–F and Fe₃O₄@Ti/CN–F. The results demonstrate that these three demulsifiers exhibit excellent demulsification efficiency, acid resistance, and excellent recyclability. They achieve demulsification rates exceeding 85% in neutral and acidic environments. Notably, Fe₃O₄@Ti/G–F stands out with the best performance. After five cycles of recovery from a biphasic system, its demulsification efficiency remains above 70%. When used at a concentration of 600 mg L⁻¹, it can achieve a demulsification rate of 93.44% within just 30 minutes. In summary, this innovative magnetic nanodemulsifier not only provides an efficient and stable solution for crude oil emulsion separation but also offers significant ecological benefits, holding great potential for application in the treatment of oily wastewater.

We integrate machine learning (ML) with TiO₂–zeolite photocatalysis to convert biomass-derived 4-vinylguaiacol (4-VG) to vanillin via partial oxidation, thereby elucidating the dominant descriptor governing vanillin selectivity. Exploratory screening of a set of 16 zeolites and 12 TiO₂ photocatalysts revealed that composite systems enhance vanillin selectivity up to 36%, compared with 15% for TiO₂ alone. ML models such as random forest (RF), trained on 20 zeolite datasets (16 training and 4 test samples) incorporating six physicochemical descriptors, identified the Si/Al ratio of zeolite as the dominant descriptor. Validation experiments guided by ML predictions attributed its effect to pH buffering at the TiO₂ liquid interface, sustaining an alkaline microenvironment and stabilizing selectivity against pH drift. The synergy between ML analysis and ML-guided validation experiments proved effective even when applied to chemically curated datasets of limited size, providing transferable design principles for composite photocatalysts.

The preparation of efficient and eco-friendly catalysts for the cycloaddition of CO₂ and epoxides has been extensively researched for a long time with the aim of achieving green chemistry and net zero emissions. Herein, we report commercial and synthesized boron-doped ZnO nanocatalysts for the formation of target cyclic carbonates by enhancing the efficiency of cyclization reactions of CO₂ and various epoxides through a strong synergistic effect between the metal active site and Lewis acidic boron molecules. FT-IR spectroscopy, UV-vis spectroscopy, TGA-DTA, ICP-OES, XRD, SEM, and EDX-mapping techniques were utilized for structural characterization of ZnO and ZnO-B_(1–3) nanocatalysts. The optimized ZnO and ZnO-B_(1–3) nanocatalysts efficiently carried out the coupling reaction of CO₂ and epoxides to form organic cyclic carbonates under ambient pressure, without the need for solvent, and as an alternative to the toxic and expensive phosgene gas. Among these prepared catalysts, the ZnO-B₁/PPNCl binary catalytic system was found to be the most active catalyst for the effective transformation of CO₂ into value-added cyclic carbonates, yielding 99% with ≥99% selectivity under ambient pressure at 100 °C for 24 h using epichlorohydrin (ECH). According to the catalytic results obtained, the electronic properties and defect dynamics of the ZnO structure and the synergistic effect due to the Lewis acidic properties of boron compounds significantly improved the catalytic performance during the conversion of CO₂ to cyclic carbonates. Moreover, the ZnO-B₁/PPNCl binary catalytic system demonstrated exceptional recyclability, exhibiting no decline in catalytic activity over five consecutive reaction cycles. The kinetic studies show the rate constant of the catalytic CO₂ cycloaddition reaction, and the kinetics of this coupling reaction were estimated to be pseudo-first-order, and the rate constant was 0.0875 h⁻¹ at 100 °C under similar reaction conditions.

The textile industry is one of the most polluting sectors worldwide, generating large amounts of post-consumer and industrial waste with limited recycling options and significant greenhouse gas emissions. This study assesses the environmental viability of energy recovery from textile waste through fluidized bed combustion and oxycombustion, followed by post-combustion catalytic treatment, thermal plasma application, and carbon capture. A gate-to-gate life cycle assessment (LCA) was performed using process simulation data for textile waste with a composition of 50% cotton and 50% polyester, integrating selective catalytic reduction for NO_x abatement, CaO-based treatment for CO₂ capture, and also incorporating real thermal plasma data for the destruction of dioxins and furans. Environmental impacts were quantified using the ReCiPe 2016 Midpoint (H) method. Results show that combustion with carbon capture and thermal plasma application achieved a global warming potential (GWP) of 3.6 kg CO₂ eq. per kg textile. In comparison, oxycombustion with carbon capture and thermal plasma application achieved 4.3 kg CO₂ eq. per kg textile, representing reductions of 27–57% compared to textile waste disposal in landfills, incineration, or mechanical/chemical recycling. CO₂ capture and thermal plasma were the primary contributors to environmental burdens, whereas steam generation provided significant offsetting credits. Oxycombustion increased NO_x and particulate emissions but reduced eutrophication and aquatic ecotoxicity. Overall, combustion and oxycombustion with post-combustion catalytic treatment, thermal plasma application, and carbon capture offer a promising route for the energetic valorization of non-recyclable textile waste, combining greenhouse gas reduction, energy recovery, and lower environmental impacts, supporting circular economy strategies.

The development of environmentally benign methods for synthesizing carbon nanomaterials from biomass is gaining momentum due to growing concerns about sustainability and industrial pollution. In this study, Pinus roxburghii biomass was utilized as a renewable precursor for the hydrothermal synthesis of functionalized carbon nanotubes (f-CNTs). Natural deep eutectic solvents (NADESs), formulated using various hydrogen bond donors (HBDs) and choline chloride (ChCl) as a hydrogen bond acceptor (HBA), were explored as green, structure-directing, and functionalizing agents. Among the tested combinations, [ChCl/oxalic acid] (1 : 1 molar ratio) proved most effective in directing the formation of well-defined tubular nanostructures under optimized conditions (120 °C, 5 h). The synthesized f-CNTs were subsequently applied for the adsorption of reactive orange 16 (RO16), a persistent azo dye commonly found in industrial effluents from textile-dense regions. Adsorption performance was evaluated through studying the adsorption isotherms and kinetic models, revealing that the process followed chemisorption. The thermodynamic analysis of the process was also conducted, depicting the endothermic (ΔH = 6783.47 J mol⁻¹) and spontaneous nature of the process. The synthesized f-CNTs offered a maximum adsorption capacity of 111.11 mg g⁻¹. Thus, this study illustrates the green route for the synthesis of CNTs using NADESs while meeting the sustainable development goals and also curbing the water pollution caused by reactive dyes.