Ammonia is one of the most important chemicals in the world because it is a feedstock for fertilizer production and, moreover, it has been proposed as a convenient storage media for renewable H2. Currently, it is produced by Haber-Bosch process, which entails harsh operation conditions and a high carbon footprint, rendering the process difficult to be run by renewable energy. Therefore, substituting the conventional Haber-Bosch process for other approach less energy-intensive and carbon-free is and urgent need. A milder process for ammonia synthesis will enable the implementation of smaller distributed plants more aligned with renewable energies. For this reason, there is a plethora of current research focusing on the development of suitable catalysts with higher activity and selectivity for nitrogen reduction and processes that will work under less severe operating conditions or even at ambient conditions. Some of the most relevant research approaches are here revised and compared.
Alternating ring‐opening copolymerization of cyclic anhydrides and epoxides by zeolitic imidazolate framework‐67: A promising approach
The zeolitic imidazolate framework-67 was used as a heterogeneous catalyst for the alternatively ring opening copolymerization of epoxides and cyclic anhydrides without co-catalyst and initiator.
The ring opening copolymerization (ROCOP) of epoxides and cyclic anhydrides is one of the most important ways to synthesize polyesters both in industrial and academic fields. Herein, the zeolitic imidazolate framework-67 (ZIF-67) was used as a heterogeneous catalyst for the ROCOP of epoxides and cyclic anhydrides without co-catalyst and initiator. Notably, the obtained polyesters with alternate structures were proved by the 1H NMR spectrum and FTIR spectrum, which indicate the ROCOP is alternatively copolymerized. Kinetic study of the ROCOP of cyclohexene oxide (CHO) and phthalic anhydride (PA) shows that the polymerization reaction is first-order kinetics. The apparent activation energy (Ea) of the ROCOP of CHO and PA catalyzed by ZIF-67 was found to be about 104.4 KJ/mol. A possible mechanism of ROCOP of CHO and PA is that the metal Co coordinates with the oxygen atom on the monomer to weaken the C-O bond thereby opening the ring structure and initiating the copolymerization reaction. In this study, a new system for the copolymerization of epoxide and anhydride catalyzed by heterogeneous catalysts was discovered, which has important guiding significance.
Solvothermal single‐pot synthesis of Pd‐Fe3O4@GO catalyst: Enhanced catalytic performance in Sonogashira coupling reactions
We developed a single-pot solvothermal synthetic approach to synthesizing Pd-Fe3O4@GO. It is a simple, effective, magnetically separable, eco-friendly, and recyclable catalyst. The synthesized catalyst Pd-Fe3O4@GO was thoroughly characterized using FTIR, XPS, XRD, SEM-EDS mapping, TEM, and ICP-MS. The synthesized catalyst was used in the Sonogashira cross-coupling reaction between substituted aryl halide and phenylacetylene to form carbon–carbon bonds.
In this study, we present a new approach to synthesizing a magnetically separable Pd-Fe3O4@GO catalyst using a simple single-pot method. The catalyst was employed in Sonogashira coupling reactions, demonstrating excellent results. The catalyst was studied using a various characterization method, including X-ray photoelectron spectroscopy (XPS), scanning electron microscope–energy-dispersive X-ray spectroscopy (SEM-EDS) mapping, TEM, X-ray diffraction (XRD), FTIR, and inductively coupled plasma mass spectrometry (ICP-MS). Pd-Fe3O4@GO exhibited superior catalytic activity compared with its conventional counterparts in phenylacetylene-iodobenzene coupling reactions under copper co-catalyzed-free and ligand-free conditions, with a higher turnover frequency (TOF) of 118.3 h−1. Optimized conditions yielded high yields for various substrates, including inactive aryl chloride and bromide substrates, emphasizing its versatility. Also, a reaction mechanism was proposed and a kinetic model was developed. The catalyst's green chemistry potential was highlighted because of its high efficiency, purity of products, recoverability, and ease of preparation. Moreover, Pd-Fe3O4@GO demonstrated impressive stability through multiple recycling rounds without loss of functionality, making it a promising tool for sustainable chemical processes.
Cover Picture: (Isr. J. Chem. 1‐2/2024)
The cover picture shows a cyclic voltammogram and catalytically active intermediates, highlighting the importance of a rationale for innovations in the rapidly evolving field of molecular electrosynthesis. Also, as a product structure, a C7 substituted indole, derived through electrocatalysis, is depicted.
The 4th Bowei Research Conference (BRC‐4), January 3–5, 2024, Teachers′ Hostel, Sun Moon Lake, Taiwan
Special Issue on Electrochemically‐Driven Organic Synthesis
Israel Journal of Chemistry, Volume 64, Issue 1-2, January 2024.
Recent Advances in Electrochemical Reductive Transformation of C−C and C−O Multiple Bonds
Abstract
In recent decades, electro-organic synthesis is indubitably emerging as a cornerstone of modern organic chemistry. Electrochemical organic transformations especially reduction reactions have made massive advancements in the last few years because of their sustainable and environ-friendly nature. Electro-reductive protocols can be used as a promising substitute for conventional reductants by expelling the requirement of the stoichiometric amount of metal reductants. The major challenges for these electro-reductive reactions are primarily the use of a sacrificial electrode and divided cells. These limitations can be resolved through smart reaction planning by employing cheap sacrificial reagents or paired electrolysis without compromising the sustainable viewpoint. Considering the rapid enhancement in this field, imparting an intangible understanding of this evolving area is essential and substantial. In this review, we portrayed the electrochemical reductive transformations of C−C and C−O bonds after 2015 along with detailed mechanistic insights.
Synthesis of Ag @CuO nanocomposites supported by reduced graphene oxide nanosheets: harnessing photocatalytic degradation of naphthol blue black dye
We provide the very facile method for the synthesis of nanocomposite. We have shown that how the addition of silver has increased the photocatalytic activity toward dye degradation. We have provided much detail on reduced graphene oxide-based composites and their synergistic properties. The nanocomposites have been characterized by several advanced techniques including XRD, EIS, FTIR, XPS, and EPR.
The significance of utilizing photocatalysts to degrade toxic dyes and microbes has grown in recent years. It has been demonstrated as a successful method for utilizing light through hybrid photocatalysts to break down harmful organic molecules. This study aims to investigate the potential applications of CuO–Ag/rGO nanocomposites in environmental remediation. The nanocomposites were synthesized by incorporating Ag and CuO nanoparticles onto rGO nanosheets via hydrothermal method. The nanocomposites that resulted were thoroughly characterized using various analytical techniques to determine their chemical structure, morphology, crystallinity, and photocatalytic application. The degradation efficiency of naphthol black blue (NBB) dye under visible light irradiation was used to assess the photocatalytic performance of the nanocomposites. It was revealed that 80.2%, 90.3%, and 97.3% of NBB dye degraded as a result of enhanced photocatalytic activity of synthesized CuO–Ag/rGO. The research provides valuable insights into the design and development of advanced nanomaterials for efficient and sustainable wastewater treatment applications.
Defect Engineering in GO Membranes – Tailoring Size and Oxidation Degree of Nanosheet for Enhanced Pore Channels
The schematic illustrates the separation mechanism of pGO membranes. The L-pGO membrane, with extended interlayer mass transfer paths, regular pores, and abundant in-plane defects, exhibits superior permeability. In contrast, the S-pGO membrane, with shorter paths and fewer in-plane defects, excels in dye rejection.
Abstract
Graphene Oxide (GO) membrane has been extensively applied in the field of water purification and membrane separation processes. While the solute molecule transport in GO membranes encompasses interlayer channels, edge defects, and in-plane crack-like holes, the significance of edge defects or crack-like pores in ultrathin membranes is often overlooked. In our study, we focused on the construction of short-range channel GO membranes with varied defect structures by modulating the transverse size of the porous nanosheets. GO nanosheets with different sizes were procured through high-energy γ-irradiation combined with centrifugation. Notably, the large-sized porous GO nanosheets (L-pGO) exhibit a consistent structure, and numerous in-plane defects. In contrast, the smaller counterparts (S-pGO) present a fewer in-plane defects. The performance metrics revealed that L-pGO exhibited a water flux of 849.25 L m−2 h−1 bar−1, while S-pGO demonstrated nearly 100 % dye rejection capacity. These findings underscore the potential of defect engineering as a powerful strategy to enhance the efficiency of two-dimensional membranes.
The dopamine D2 receptors antagonist Veralipride inhibits carbonic anhydrases: solution and crystallographic insights on human isoforms
This study explores veralipride, a benzamide-class antipsychotic and dopamine D2 receptor antagonist, for its inhibitory effects on carbonic anhydrase (CA) isoforms. In vitro profiling reveals potent inhibition across hCA I, II, and CA XII. In addition, X-ray crystal structure experiments of veralipride adducts with hCA I, II, and CA XII mimic elucidates molecular interactions, aiding in designing polypharmacological compounds.
Abstract
The inhibitory effects of veralipride, a benzamide-class antipsychotic acting as dopamine D2 receptors antagonist incorporates a primary sulfonamide moiety and was investigated for its interactions with carbonic anhydrase (CA) isoforms. In vitro profiling using the stopped-flow technique revealed that veralipride exhibited potent inhibitory activity across all tested hCA isoforms, with exception of hCA III. Comparative analysis with standard inhibitors, acetazolamide (AAZ), and sulpiride, provided insights for understanding the relative efficacy of veralipride as CA inhibitor. The study reports the X-ray crystal structure analysis of the veralipride adduct with three human (h) isoforms, hCA I, II, and CA XII mimic, allowing the understanding of the molecular interactions rationalizing its inhibitory effects against each isoform. These findings contribute to our understanding of veralipride pharmacological properties and for the design of structural analogs endowed with polypharmacological properties.