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Environmental consciousness made humankind focus on sustainable and low carbon footprint fuels, and biodiesel is one such fuel. As biodiesel production increases, so does the surplus production of glycerol, necessitating the development of methods to convert glycerol into more valuable products. In this study, activated carbon-supported Pt–V bimetallic catalysts were synthesized and evaluated for selective glycerol oxidation to lactic acid. The physicochemical properties of the prepared catalysts were thoroughly evaluated using various advanced characterization techniques, such as field emission transmission electron microscopy (FETEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), N2-sorption analysis, and X-ray photoelectron spectroscopy (XPS). The bimetallic catalysts performed better than monometallic Pt and V catalysts, indicating the synergistic effect. The 1 : 1 weight ratio of Pt : V (1Pt–1V/AC) showed excellent activity towards lactic acid production from glycerol oxidation with a yield of 80% at 100% glycerol conversion under moderate reaction conditions (NaOH/glycerol = 1 : 1 mol mol−1, 4400 glycerol/metal molar ratio, 473 K, 5 bar air, 12 h reaction time). The 1Pt–1V/C bimetallic catalyst also showed good stability up to four cycles with only minor activity loss in the first cycle.

Glycidyl methacrylate (GMA) and styrene (St) were grafted to the molecular chains of poly(ethylene-octene) (POE)/linear low-density polyethylene (LLDPE) using the bi-functional cooperative grafting method of in situ reactive melting grafting technology to prepare a series of GMA-functionalized (POE/LLDPE)-g-(GMA-co-St) graft copolymers. Then the graft copolymers were blended with poly(butylene terephthalate) (PBT) to prepare PBT/(POE/LLDPE)-g-(GMA-co-St) blends. The effects of the reactive functional group amount (GMA) in the graft copolymer on the rheological, thermal, and mechanical properties and phase morphology of the blends were studied in detail, and the toughening mechanism was analyzed comprehensively. The results showed that the (POE/LLDPE)-g-(GMA-co-St) graft copolymers had a good toughening effect on the PBT resin, and the compatibility between PBT and the dispersed phase could be effectively improved by introducing a small amount of GMA in the graft copolymers. The Izod impact strength, tensile strength and elongation at break of the PBT/(POE/LLDPE)-g-(GMA-co-St) blends were significantly improved, and blends with excellent comprehensive properties were obtained. Furthermore, the thermal stability, dynamic modulus, and complex viscosity of the blending system gradually increased, the size of the dispersed phase particles gradually decreased, and the mechanical properties gradually increased with increased GMA amount in the graft copolymer (2–5 wt%). Additionally, the blends were fractured in a ductile manner within the GMA amount range investigated. Cavitations were created inside the (POE/LLDPE)-g-(GMA-co-St) particles. Their exfoliation released three-dimensional static stress to initiate matrix yielding and absorb more energy to achieve better toughness of the blends. However, the reaction system underwent severe cross-linking side reactions when the GMA amount added in the graft copolymer was too high (6 wt%), deteriorating the performance of (POE/LLDPE)-g-(GMA-co-St) and ultimately damaging the phase morphology of the blends and their mechanical properties.

Continuous flow reactors integrated with spectroscopic instruments allow for rapid collection of informative spectral data. The measured spectral data and a calibration model can be used to monitor reaction progress, elucidate reaction kinetics, and gain mechanistic insights efficiently. However, developing a calibration model is a time and resource-consuming task. Here, we propose a novel calibration-free integrated model identification framework, called, a semi-supervised machine learning approach (SSML) for identifying reaction systems rapidly using spectral data with minimal labelled data. Using the proposed SSML approach, the stoichiometric matrix and physically meaningful extents of reaction are identified from spectral data alone without invoking kinetic models. Subsequently, the computed extents are used for kinetic model discrimination and parameter estimation using the incremental identification method. The proposed method is demonstrated using an enzymatic hydrolysis reaction and a complex Wittig reaction system carried out in a micro-reactor equipped with an in situ UV-visible spectrophotometer. The results from the proposed calibration-free modelling framework are compared with those obtained using the traditional calibration-based method.

In this study, Ag/TiO2−X nanotubes with oxygen defects were synthesized by a simple and controllable predischarge–electrodeposition method, and they were calcined in H2/N2. After Ag modification, the maximum transient photocurrent of TiO2 nanotubes increased by 22.4 times. In addition, compared with that of pure TiO2 nanotubes, the photocatalytic performance of the Ag/TiO2−X nanotubes for degradation of methylene blue and aqueous formaldehyde was enhanced by 6.9 and 3.5 times, respectively. There are two reasons for the strengthened photocatalytic performance of Ag/TiO2−X. One is the localized surface plasmon resonance effect of Ag nanoparticles, which effectively promotes the separation of photogenerated electron–hole pairs. The other is that the oxygen defects act as shallow donors and accelerate charge transfer at the interface. This work provides a research idea for fabricating nanocomposites applied in photoelectrochemical and photocatalytical fields.

The rising demand for the three-carbon diol 1,3-propanediol (1,3-PDO) in various industrial applications, including food, lubricants, drugs, and new polyester polymer materials, has spurred notable interest in development of environmentally sustainable processes. These processes aim to fulfill the increasing demand for 1,3-PDO while simultaneously addressing the climate and environmental issues linked to fossil-based chemical production. In this study, we successfully synthesized 1,3-PDO directly from glucose using a well-established safety strain Klebsiella oxytoca. We employed a systematic metabolic engineering strategy to enhance 1,3-PDO production, including screening glycerol synthesis pathways, blocking competing by-product biosynthetic pathways, increasing carbon flux towards 1,3-PDO synthesis, and replacing the glucose transport system. As a result, the engineered strain achieved a flask fermentation titer of 6.2 g L−1 1,3-PDO. These findings hold significant implications for future research on utilizing this strain for efficient bioconversion of glucose to 1,3-PDO.

Mechanochemistry is becoming an enabling technology for the synthesis of organic and inorganic compounds as well as for the synthesis of polymers as it underlines sustainability in a significant manner. Continuous mechanochemical synthesis further adds value to the approach through consistency, smaller footprint, and better energy efficiency. This review gives an indepth view of the present status of this subject along with critical engineering aspects that one needs to measure and monitor as eventually synthesis needs to be transformed into a process. The examples covered herein include the synthesis of organic compounds, viz., APIs, agrochemical intermediates, catalysts, and polymers. In the end, we also discuss the safety aspects of mechanochemical synthesis and recommendations for exploring this field further.

Electrochemical reactions under constant current can be completed within very short periods of time in microliter-volume cells, as electrolysis time is proportional to the quantity of material processed. A flexible electrochemical microreactor with 17 μL volume has been designed and constructed, which enables reactions to be performed in as little as 7.3 s residence time using standard, commercially available electrodes. By utilizing automation and statistical analysis, the reaction design space was explored for three model reactions in 2–3 hours, consuming only 30–300 mg of material for 42 experiments.

We present a microrectification platform to separate effectively binary liquid mixtures, using n-hexane and cyclohexane as a model system. We design and 3D print rectification columns with three different tray structures and one packed structure for enhanced mass transfer. In the experiments, at a reflux ratio of 4.0, we obtain a height equivalent of a theoretical plate (HETP) of 10.3 mm using a designed tray structure, demonstrating an efficient process. We further develop a mass transfer model to obtain the gas–liquid mass transfer coefficient for optimal process design. Our approach that leverages the advantages of 3D printing offers an effective solution for separation of liquids with close boiling points.

The activation capacity of molecular oxygen is an important indicator to evaluate the photocatalytic efficiency of a catalyst. In this paper, MoO3−x nanosheets with oxygen vacancies were deposited on WO3 nanoflowers to form a WOM heterojunction, which improved the photocatalytic performance and molecular oxygen activation ability of the catalyst. This novel WOM heterojunction exhibited excellent photoactivity for degrading rhodamine B (RhB), photocatalytic water splitting ability and molecular oxygen activation ability under sunlight irradiation. Among all the samples, WOM83% could degrade 98% of 30 ppm RhB in 40 min. Meanwhile, WOM83% exhibited the highest hydrogen generation rate (4214.2 μmol h−1 g−1) and the strongest TMB oxidation capacity, and can generate 2.23 μmol of ·O2− in 50 min. The enhanced photocatalytic performance via heterojunction construction may be attributed to these following reasons: (i) higher light absorption achieved by the MoO3−x and WO3 composite; (ii) the matched energy band gap of MoO3−x and WO3 led to higher photogenerated carrier mobility; (iii) MoO3−x with oxygen vacancies as electron traps suppressed the photogenerated carrier recombination; (iv) enhanced molecular oxygen activation ability of the WOM heterojunction, such as the production of ·O2−. The measurements for TMB photo-oxidation and ·O2− showed excellent molecular oxygen activation ability of WOM heterojunctions. Finally, a possible photocatalytic mechanism was proposed. This study provided a viable option for the application of materials with oxygen vacancies to remove pollutants and improve molecular oxygen activation ability.

Kinetic screening, when conducted in batch or under steady state flow conditions, is time consuming. In this work we leverage transient flow experiments to investigate the hydrogenation of an aryl ketone in a gas–liquid flow reactor, catalyzed by catalytic static mixers and monitored using process analytical technologies. Ramping reactor parameters over time allowed the exploration of different residence times and temperatures in a single experiment, allowing rapid definition of the reaction network. Data analysis using a batch approximation approach and a plug flow reactor approach allowed parameterization of predictive reaction models. A Pd/Al2O3 catalyst performed ketone reduction, followed by dehydration to the ethylbenzene derivative. Conversely, Pt/Al2O3 and Ru/Al2O3 showed aromatic ring hydrogenation as the main reaction pathway, following ketone reduction. The developed workflow is likely to be highly applicable to other chemical systems and reaction types.

For the first time, a reusable heterogeneous Smopex-101 and TiO2 dual catalytic system was employed successfully for the energy-efficient and eco-friendly synthesis of 5-(chloromethyl) furfural (5-CMF) from soluble starch (SS) under the synergistic photo-thermal effect of UV-ultrasound (US) irradiation. Under mild optimal operating conditions (80 °C, 60 min), the batch (UVUS-BR) and continuous-flow rectangular packed bed reactors (UVUS-RPBR) both resulted in maximum 5-CMF yields of 60.54 mol% and 58.75 mol%, respectively. Significantly, the first-ever heterogeneous surface reaction kinetic model was formulated for the 5-CMF synthesis process, which revealed that the activation energies needed for the different reaction steps involved in the consecutive reaction pathway were 79.04 kJ mol−1 (SS hydrolysis), 61.55 kJ mol−1 (glucose dehydration), and 52.2 kJ mol−1 (5-hydroxymethylfurfural chlorination). RTD analysis and ANSYS fluent simulation study revealed that the utilization of the US energy significantly reduced the non-ideal behavior of UVUS-RPBR (63% reduction in dispersion number). Moreover, the efficacy of UVUS-RPBR in the 5-CMF synthesis process was evaluated, employing the experimentally validated heterogeneous kinetic model parameters. Furthermore, based on comparative LCA analysis, cyclohexane was identified as the most favorable solvent for in situ 5-CMF (purity: 96%) extraction due to its potential environmental advantages over other solvents. The outcomes of the present study can be useful for the scale-up of such reactors for industrial application.

Correction for ‘From traditional to greener alternatives: potential of plant resources as a biotransformation tool in organic synthesis’ by Vinay Kumar et al., React. Chem. Eng., 2023, 8, 2677–2688, http://doi.org/10.1039/D3RE00346A.

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In this study, an approach based on microwave-enhanced CO2 hydrogenation to olefins was carried out in a two-zone hybrid heating reactor system at moderate pressures of 20–140 psig. Methanol synthesis was conducted in a microwave heated zone over a stable Cu/ZnO/Al2O3 catalyst and the methanol conversion to olefins was conducted in a conventional thermally heated zone over SAPO-34 zeolite. This work demonstrates the potential of microwave-driven catalytic technology to decarbonize greenhouse gases into valuable chemicals utilizing green hydrogen under mild conditions.

Valorization of technical lignin is crucial for the circular bioeconomy – this can be achieved by the transformation of lignin to high-value nanomaterials. However, the majority of lignin nanoparticle (LNP) production methods require high volumes of organic solvent, and specialized equipment, or fail in certain cases to produce a morphologically uniform product with superior physicochemical properties to technical lignin. Herein, a binary solvent system of subcritical water and acetone based on the principles of solvent–antisolvent (SAS) precipitation of lignin is proposed. Spherical LNPs with a high degree of uniformity in the chemical structure are produced via a batch reactor from kraft lignin demonstrating high yield (88–92%), colloidal stability in water, thermal stability, and low mean particle size – these are desirable for advanced biocomposite and biomedical applications; achieved in this study by using lower volumes of recyclable acetone (4–7 times less) than previously reported.

Additive manufacturing, or three-dimensional (3D) printing, is an accessible, quick, and user-friendly tool for fabricating reactors and chemical processing devices. Here we report a method for printing filtration and separation devices using fused-deposition modelling (FDM) which incorporate commercial porous membranes. By using exogenous membranes, membrane pore size and material can be arbitrarily specified allowing much greater versatility in device design. We show for the first time that fully operational monolithic devices can be created without need for post-printing assembly and demonstrate the efficacy of the approach by making and testing three distinct devices: dead-end filters, which can be made in a range of sizes and are shown to fully remove micron-sized particles from a heterogenous mixture; liquid–liquid separators, which are shown to completely separate segmented flows of immiscible liquids; and a cross-flow filtration device, which is shown to achieve near full dye removal from an aqueous stream with a residence time of 3.4 minutes. For the cross-flow filtration device we describe a new “double-sided” printing technique whereby the plastic is directly printed onto both sides of the membrane to ensure the membrane is fully bonded to the 3D printed body. The range of devices showcased here highlights the versatility of the approach and its potential for use in chemical processing applications that require porous membranes.

Heavy metal ions and organic dyes are some of the main pollutants in water environments, which have the potential to cause harm to the ecological environment and human health. Although adsorption technology has been widely used in the treatment of pollutants in water, the selection of adsorbents is still a challenge considering the adsorption capacity and regeneration ability of the adsorbents. This article reports a new type of composite nanomaterial Fe3O4/UiO-66-NH2@EDTA-GO with magnetic and highly structured pore channels. The composite material is composed of Fe3O4, UiO-66-NH2, and functionalized graphene oxide, which has the advantages of magnetic recovery, high surface area, and well-developed porous structure. The adsorption behavior of the target pollutants on Fe3O4/UiO-66-NH2@EDTA-GO was investigated by batch adsorption experiments. The experimental results show that when the initial concentration of the target pollutants is 100 mg L−1, the temperature is 293 K, and the solution pH is 6, the adsorption capacity of Pb(II) reaches 82.81 mg g−1 after 60 min of adsorption, the adsorption capacity of methyl orange (MO) reaches 61.08 mg g−1 after 30 min of adsorption, and the adsorption capacity of methylene blue (MB) reaches 86.48 mg g−1 after 60 min of adsorption. This experiment also studied the adsorption capacity of Fe3O4/UiO-66-NH2@EDTA-GO for organic–inorganic binary composite pollutants and the interaction between different pollutants in the composite pollution system. The results show that the composite material has efficient adsorption capacity for different types of pollutants. The component analysis of the samples before and after adsorption was carried out by XPS, and Fe3O4/UiO-66-NH2@EDTA-GO has different adsorption mechanisms for different types of pollutants. This study provides a foundation for the application of new composite materials, which has important scientific and practical significance.

Selective hydrogenation of alkynol compounds to produce high value-added enols is an important reaction in the fine chemical industry. The construction of selective hydrogenation catalysts for alkynols is challenging because the alkynyl group is prone to over hydrogenation and the selectivity in the hydrogenation is always low. Herein, a simple sacrificial template strategy was designed to prepare mesoporous CeO2, on which ultrafine and highly-dispersed bimetallic PdCu nanoparticles were anchored, obtaining the PdCu@CeO2 catalyst. Introducing non-precious metallic Cu can improve the selectivity of precious metal Pd catalysts for the selective hydrogenation of alkynols through electronic and geometric modulation. The obtained PdCu@CeO2 catalyst showed high selectivity (99%) and good recyclability for the selective hydrogenation of the probe compound propynol ethoxylate under mild conditions. The PdCu@CeO2 catalyst also exhibited excellent performance in the catalytic selective hydrogenation of various substituted alkynols. Therefore, this research work provides a feasible strategy for the effective regulation of catalytic performance, which has potential application for the efficient catalytic selective hydrogenation of alkynols in the fine chemical industry.