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Due to the excessive consumption of fossil fuel resources and the emission of a substantial quantity of CO2 into the environment, it is urgent to develop clean energy solutions. In order to reduce carbon emissions from the source, it is effective approach to convert CO2 into various renewable energy fuels. Inspired by the photosynthesis of green plant, CO2 is converted into clean fuel with the aid of catalysts. Regarding the separation and transfer of photogenerated charge carriers, and inadequate adsorption and activation of CO2 on the surface of catalysts, the current semiconductors utilized in photocatalysis have low efficiency. As a result, the current efficiency of photocatalysts is far from meeting the need for practical industrial demands. MXene materials, for example Ti3C2Tx (9980 S cm−1), have emerged as a promising candidate for CO2 reduction due to the significant number of active sites for functional groups, high conductivity and low defects, large surface areas, and outstanding visible light photoelectronic properties. This review provides a critical overview of the recent progress regarding MXene as a co-catalyst in photocatalytic CO2 reduction systems. We systemically explore the fundamental principles and reaction mechanisms associated with separating and transferring photogenerated charge carriers. Additionally, we investigate the basic properties of MXene as a co-catalyst in the context of CO2 reduction. Furthermore, this review also elucidates the impacts of the microstructure of photocatalysts on enhancing photocatalytic performance. Finally, the challenges and opportunities in using MXene as a co-catalyst for CO2 reduction have been presented to inspire further research in this field.

Acrylamide is an unsaturated amide that forms in heated, starchy food products. This study was conducted to (1) examine the ability of 38 LAB to remove acrylamide; (2) optimize acrylamide removal of selected LAB under various conditions (pH, temperature, time and salt) using the Box–Behnken design (BBD); (3) the behavior of the selected LAB under the simulated gastrointestinal conditions; and (4) investigate the mechanism of adsorption. Out of the 38 LAB, Enterococcus durans and Enterococcus faecalis had the highest results in removing acrylamide, with 33 and 30% removal, respectively. Those two LAB were further examined for their binding abilities under optimized conditions of pH (4.5–6.5), temperature (32°C - 42°C), time (14–22 h), and NaCl (0–3% w/v) using BBD. pH was the main factor influenced the acrylamide removal compared to other factors. E. durans and E. faecalis exhibited acrylamide removal of 44 and 53%, respectively, after the in vitro digestion. Zeta potential results indicated that the changes in the charges were not the main cause of acrylamide removal. Transmission electron microscopes (TEM) results indicated that the cell walls of the bacteria increased when cultured in media supplemented with acrylamide.

Abstract The construction of photocatalytic systems that have strong redox capability, effective charge separation, and large reactive surfaces is of great scientific and practical interest. Herein, an edge‐connected 2D/2D Z‐scheme system that combines the facet junction and the interfacial heterojunction to achieve effective long‐range charge separation and large reactive surface exposure is designed and fabricated. The heterostructure is realized by the selective growth of 2D‐layered MoS2 nanoflakes on the edge‐sites of thin TiO2 nanosheets via an Au‐promoted photodeposition method. Attributed to the synergetic coupling of the facet junction and the interfacial heterojunction that assures the effective charge separation, and the tremendous but physically separated reactive sites offered by layered MoS2 and highly‐exposed (001) facets of TiO2, respectively, the artificial Z‐scheme exhibits excellent photocatalytic performance in photodegradation tests. Moreover, the junctional plasmonic Au nanoclusters not only act as electron traps to promote the edge‐selective synthesis but also generate “hot electrons” to further boost photocatalytic performance. The Z‐scheme charge‐flow direction in the heterostructure and the roles of electrons and holes are comprehensively studied using in situ irradiated X‐ray photoelectron spectroscopy and photodegradation tests. This work offers a new insight into designing high‐performance Z‐scheme photocatalytic systems.

Meropenem is currently the most common carbapenem in clinical applications. Industrially, the final synthetic step is characterized by a heterogeneous catalytic hydrogenation in batch mode with hydrogen and Pd/C. The required high-quality standard is very difficult to meet and specific conditions are required to remove both protecting groups [i.e., p-nitrobenzyl (pNB) and p-nitrobenzyloxycarbonyl (pNZ)] simultaneously. The three-phase gas–liquid–solid system makes this step difficult and unsafe. The introduction of new technologies for small-molecule synthesis in recent years has opened up new landscapes in process chemistry. In this context, we have investigated meropenem hydrogenolysis using microwave (MW)-assisted flow chemistry for use as a new technology with industrial prospects. The reaction parameters (catalyst amount, T, P, residence time, flow rate) in the move from the batch process to semi-continuous flow were investigated under mild conditions to determine their influence on the reaction rate. The optimization of the residence time (840 s) and the number of cycles (4) allowed us to develop a novel protocol that halves the reaction time compared to batch production (14 min vs. 30 min) while maintaining the same product quality. The increase in productivity using this semi-continuous flow technique compensates for the slightly lower yield (70% vs. 74%) obtained in batch mode.

Continuous-flow chemistry has become a mainstream process and a notable trend among emerging technologies for drug synthesis. It is routinely used in academic and industrial laboratories to generate a wide variety of molecules and building blocks. The advantages it provides, in terms of safety, speed, cost efficiency and small-equipment footprint compared to analog batch processes, have been known for some time. What has become even more important in recent years is its compliance with the quality objectives that are required by drug-development protocols that integrate inline analysis and purification tools. There can be no doubt that worldwide government agencies have strongly encouraged the study and implementation of this innovative, sustainable and environmentally friendly technology. In this brief review, we list and evaluate the development and applications of continuous-flow processes for antibiotic synthesis. This work spans the period of 2012–2022 and highlights the main cases in which either active ingredients or their intermediates were produced under continuous flow. We hope that this manuscript will provide an overview of the field and a starting point for a deeper understanding of the impact of flow chemistry on the broad panorama of antibiotic synthesis.

Cefonicid is a second-generation cephalosporin sold under the brand name Sintocef™. It is an injectable drug obtained via a freeze-drying process and is also available for oral preparations. The high-quality standard required is very challenging to satisfy, and current production protocols are characterized by steps that are lengthy and cumbersome, making the product unattractive for the international market. Industrial R&D is constantly working on the process optimization for API synthesis, with the aim of increasing productivity and decreasing production costs and waste. We herein report a new and efficient method for the synthesis of the cefonicid benzathine salt that provides a good yield and high product stability. The double-nucleophilic and lipophilic nature of N′,N″-dibenzylethylene diacetate enables the deformylation of the OH-protected group on the mandelic moiety and also enables product crystallization to occur. We demonstrate that the formyl group in the peculiar position has high reactivity, promoting an amidation reaction that deprotects a hydroxy group and generates a new C-N bond in the reaction by-product. Several amines and OH-protected groups have been studied, but none were able to replicate the excellent results of benzathine diacetate.

Acrylamide is a toxic compound that is formed in cooked carbohydrate-rich food. Baking, roasting, frying, and grilling are cooking methods that cause its formation in the presence of reducing sugar and asparagine. To prevent acrylamide formation or to remove it after its formation, scientists have been trying to understand acrylamide formation pathways, and methods of prevention and removal. Therefore, this study aimed to: (1) screen newly isolated LAB for acrylamide removal, (2) optimize conditions (pH, temperature, time, salt) of the acrylamide removal for selected LAB isolates using Box–Behnken design (BBD), (3) investigate the acrylamide removal abilities of selected LAB isolates under the in vitro digestion conditions using INFO-GEST2.0 model, and (4) explore the mechanism of the acrylamide removal using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), zeta potential, transmission electron microscopy (TEM) measurement, and Fourier transform infrared spectroscopy (FTIR). Forty strains were tested in MRS broth, where Streptococcus lutetiensis and Lactiplantibacillus plantarum had the highest capability of acrylamide removal by 39% and 26%, respectively. To enhance the binding ability, both strains were tested under controlled conditions of pH (4.5, 5.5 and 6.5), temperature (32 °C, 37 °C and 42 °C), time (14, 18 and 22 h), and NaCl (0%, 1.5% and 3% w/v) using Box–Behnken design (BBD). Both strains removed more acrylamide in the range of 35–46% for S. lutetiensis and 45–55% for L. plantarum. After testing the bacterial binding ability, both strains were exposed to a simulated gastrointestinal tract environment, removing more than 30% of acrylamide at the gastric stage and around 40% at the intestinal stage. To understand the mechanism of removal, LAB cells were characterized via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM) techniques. Cell charges were characterized by zeta potential and functional groups analyzed by Fourier transform infrared spectroscopy (FTIR). Results indicated that increasing cell wall thickness improved acrylamide adsorption capacity. Both FTIR and EDS indicated that functional groups C=O, C-O, and N-H were associated with acrylamide adsorption.

Photocatalysis is a promising technology from economic, energetic, and ecological points of view because it takes advantage of solar light. Hence, it is one of the investigated green routes to produce hydrogen from renewable energy resources. Butyric acid (BA) is largely present in wastewater and as an intermediate product in anaerobic digestion and therefore it is an inexpensive resource, which can be converted to valuable chemicals. In this work, photoreforming of butyric acid (BAPR) under UV light in aqueous suspensions of platinum-modified titanium dioxide-based catalysts is reported for the first time. Titania nanotubes (TNT) synthesized and calcined at different temperatures (300, 400, 500°C) and commercial TiO2 (P25), decorated with platinum nanoparticles, have been tested and characterized through different techniques including X-ray powder diffraction, UV-vis diffuse reflectance and photoluminescence spectroscopy, transmission electron microscopy, BET and porosimetry analysis. The main identified products of the BAPR were H2, propane, CO2 and several organic acids (e.g., pentanoic and 3-methylhexanoic acid). It has been found that the morphology and crystallinity of the photocatalysts affected dramatically their optical properties and, consequently, the reaction rate and the product distribution. Specifically, the highest conversion of BA (XBA) and selectivity toward H2 (SH2) was recorded with P25-Pt (XBA = 26.9%, SH2 = 47.2% after 8 h of irradiation). TNT-400-Pt showed the highest selectivity toward propane (SC3H8 = 16.1%) with XBA = 23.4% and SH2 = 36.2%. The activity results in conjunction with the characterization of the catalysts highlighted that the main factor affecting the activity in terms of XBA and generation of H2 was the crystallinity, and in particular the presence of rutile phase in TiO2, whereas SC3H8 appears to increase when the electron-holes recombination is lower.

Photocatalysis emerged in the last decades as a versatile technology, whose applications range from environmental remediation to hydrogen production, energy harvesting, and organic synthesis, with exciting examples also in medicine, electronics, and advanced functional materials [...]

Among all greenhouse gases, CO2 is considered the most potent and the largest contributor to global warming. In this review, photocatalysis is presented as a promising technology to address the current global concern of industrial CO2 emissions. Photocatalysis utilizes a semiconductor material under renewable solar energy to reduce CO2 into an array of high-value fuels including methane, methanol, formaldehyde and formic acid. Herein, the kinetic and thermodynamic principles of CO2 photoreduction are thoroughly discussed and the CO2 reduction mechanism and pathways are described. Methods to enhance the adsorption of CO2 on the surface of semiconductors are also presented. Due to its efficient photoactivity, high stability, low cost, and safety, the semiconductor TiO2 is currently being widely investigated for its photocatalytic ability in reducing CO2 when suitably modified. The recent TiO2 synthesis and modification strategies that may be employed to enhance the efficiency of the CO2 photoreduction process are described. These modification techniques, including metal deposition, metal/non-metal doping, carbon-based material loading, semiconductor heterostructures, and dispersion on high surface area supports, aim to improve the light absorption, charge separation, and active surface of TiO2 in addition to increasing product yield and selectivity.

Bis-dehydroxycurcumin tert-butyl ester (K2T23) is a derivative of the natural spice curcumin. Curcumin is widely studied for its multiple therapeutic properties, including photosensitized cytotoxicity. However, the full exploitation of curcumin phototoxic potential is hindered by the extreme instability of its excited state, caused by very efficient non radiative decay by means of transfer of the enolic proton to the nearby keto oxygen. K2T23 is designed to exhibit a tautomeric equilibrium shifted toward the diketo conformers with respect to natural curcumin. This property should endow K2T23 with superior excited-state stability when excited in the UVB band, i.e., in correspondence of the diketo conformers absorption peaks, making this compound an interesting candidate for topical photodynamic therapy of, e.g., skin tumors or oral infections. In this work, the tautomeric equilibrium of K2T23 between the keto-enolic and diketo conformers is assessed in the ground state in several organic solvents by UV-visible absorption and by nuclear magnetic resonance. The same tautomeric equilibrium is also probed in the excited-state in the same environments by means of steady-state fluorescence and time-correlated single-photon counting measurements. These techniques are also exploited to elucidate the excited state dynamics and excited-state deactivation pathways of K2T23, which are compared to those determined for several other curcuminoids characterized in previous works of ours. The ability of K2T23 in photosensitizing the production of singlet oxygen is compared with that of curcumin.

A fast and efficient protocol for the synthesis of N,N'-disubstituted urea derivatives from alkyl halides and primary or secondary amines has been developed. The synthetic pathway combines nucleophilic substitutions and a Staudinger–aza-Wittig reaction in the presence of polymer-bound diphenylphosphine under 14 bar of CO2 pressure and has been performed in a one-pot two-step process. The protocol has been optimized under microwave irradiation and the scale-up experiment has been conducted under conventional conditions in a Parr reactor. The final compounds were isolated after simple filtration in almost quantitative overall yields which makes this procedure facile and rapid to execute.

A library of new heterocyclic systems was synthesized starting from oxcarbazepine (OXC, Trileptal®, 10-oxo-10,11-dihydro-5H-dibenzo[b,f]azepine-5-carboxamide). The key for these transformations is the α-enolizable ketone present on the [d]-side of our starting material OXC, thus, an in depth investigation of the literature to find heteroannulation reactions for substrates carrying an α-enolizable ketone gave us a boost to discover an excellent derivatization strategy and [3+2], [4+2] and [4+1] approaches were successfully developed. Almost always a pre-functionalization was needed, but also the direct one-pot heterocycle construction was also explored.

Zinc powder in aqueous alkaline media was employed to perform reductive amination of aldehydes with primary amines. The corresponding secondary amines were obtained in good yields along with minor amounts of hydrodimerization byproducts. The protocol is a green alternative to the use of complex hydrides in chlorinated or highly flammable solvents.