Chemically Research Articles

Development and implementation of a Python functions for automated chemical reaction balancing

<p>Chemical reaction balancing is a fundamental aspect of chemistry, ensuring the conservation of mass and atoms in reactions. This article introduces a specialized Python functions designed for automating the balancing of chemical reactions. Leveraging the versatility and simplicity of Python, the module employs advanced algorithms to provide an efficient and user-friendly solution for scientists, educators, and industry professionals. This article delves into the design, implementation, features, applications, and future developments of the Python functions for automated chemical reaction balancing. The functions thus developed were tested on some typical chemical reactions and the results are the same as that in the literature.</p>

An update on nonsteroidal anti-inflammatory drug-induced urticaria.

Hypersensitivity reactions to non-steroidal anti-inflammatory drugs (HR-NSAIDs) are common adverse events related to the widespread use of over-the-counter NSAIDs for the treatment of a variety of inflammatory conditions. Urticaria is the most commonly reported immediate cutaneous clinical sign of HR-NSAIDs, but it can be a manifestation of pathophysiologically different clinical entities that require different therapeutic strategies. The aim of this study is to ease the identification of the correct phenotype of HR-NSAIDs in patients reporting urticaria associated with the intake of NSAIDs and provide updated information about their diagnosis and management. The study is a narrative review conducted by collecting the most relevant and up-to-date data related to the classification, pathophysiology, severity, and prognosis of NSAID hypersensitivity reactions. PubMed and Embase scientific databases were used as search engines to select relevant articles. Patients developing HR-NSAIDs can be divided into two categories: selective responders (SR), who develop reactions after the administration of a single specific NSAID due to an underlying IgE or T-cell mediated hypersensitivity mechanism, or cross-intolerant (CI), who develop reactions to more than one chemically unrelated NSAIDs due to abnormalities in the biochemical pathways related with prostaglandin metabolism, independently from an underlying immunological mechanism. Five major different categories of HR-NSAIDs have been identified: NSAIDs-exacerbated cutaneous disease (NECD), NSAIDs-induced urticaria/angioedema with/without respiratory and systemic symptoms of anaphylaxis (NIUAA), and NSAIDs-exacerbated respiratory disease (NERD), which are developed by CI patients, and single NSAIDs-induced urticaria, angioedema and/ or anaphylaxis (SNIUAA) and single NSAIDs-induced delayed hypersensitivity reactions (SNIDHR), which are developed by CI patients. In vivo and in vitro diagnostic tests have rarely been shown to be reliable in all these entities and therefore are not routinely used in clinical practice. The management in SR patients consists of strict avoidance of the culprit drug, while for cross-intolerance reactions oral tolerance tests with safe alternative drugs (e.g. weak COX-1 inhibitors or selective COX-2 inhibitors) can be performed. HR-NSAIDs are being observed with increasing frequency, however, the pathogenesis behind some NSAIDS-associated clinical entities is still unclear. Diagnosis is mostly based on a thorough clinical history and confirmed by a drug challenge test. Clinical management is based on strict avoidance and use of alternative tolerated medications. Overall, all therapeutic decisions depend on the correct identification of the type of reaction the patient experienced.

Synergistic effects of Monel 400 filler wire in gas metal arc welding of CoCrFeMnNi high entropy alloy

Weldability plays a crucial role in the journey of high entropy alloys towards their engineering applications. In this study, gas metal arc welding was performed to join an as-rolled CoCrFeMnNi high entropy alloy using Monel 400 as the filler wire. The present research findings demonstrate a favorable metallurgical chemical reaction between the Monel 400 filler and the CoCrFeMnNi high entropy alloy, resulting in compositional mixing within the fusion zone that promotes a solid-solution strengthening effect, counteracting the typical low hardness associated to the fusion zone of these alloys. The weld thermal cycle induced multiple microstructure changes across the joint, including variations in the grain size, existing phases and local texture. The grain size was seen to increase from the base material toward the fusion zone. An FCC matrix and finely sparse Cr-Mn-based oxides existed in both base material and heat affected zone, while in the fusion zone new FCC phases and carbides were formed upon the mixing of the Monel 400 filler. The role of the filler material on the fusion zone microstructure evolution was rationalized using thermodynamic calculations. Texture shifted from a γ-fiber (in the base material) to a strong cubic texture in the fusion zone. Digital image correlation during tensile testing to fracture coupled with microhardness mapping revealed that, stemming from the process-induced microstructure changes, the micro and macromechanical response differed significantly from the original base material. This study successfully established a correlation between the impact of the process on the developed microstructural features and the resultant mechanical behavior, effectively assessing the processing-microstructure-properties relationships towards an improved understanding of the physical metallurgy associated to these advanced engineering alloys. In conclusion, this work provides an important theoretical framework and practical guidance for optimizing the engineering applications of high entropy alloys.

The influence of heterogeneous catalytic processes on the heat flux to the surface and the chemical composition of the shock layer at high-speed flow around blunt bodies

Numerical modeling of the high-speed flow of a multicomponent dissociated gas around a blunt body was carried out for the flow regime corresponding to the thermally stressed point of the gliding trajectory of entry into the Earth's atmosphere in the surface temperature range of 800–2000 K. As boundary conditions, a stage-by-stage model of heterogeneous catalysis of the interaction of dissociated air with the thermal protection material SiO2 was used, previously developed by the authors on the basis of transition state theory and quantum mechanical calculations. The dependence of the modes of heterogeneous chemical reactions on the surface temperature and the density of surface adsorption centers and their influence on the chemical composition of the shock layer and the convective heat flux to the streamlined surface are analyzed. The contributions of individual mechanisms of heterogeneous recombination to the total rate of formation of molecules on the surface are estimated. The possibility of using the density of adsorption sites as an effective parameter when setting boundary conditions on a real thermal protection surface in flow problems is shown.

Data analysis of non-linear radiative electro-periodic MHD flow past a stretching sheet with activation energy impact

Electro-periodic Magneto-hydrodynamics (EPMHD), activation energy, and non-linear radiation are pivotal elements in engineering and industry also contribute to advancements in fields like heat transfer, materials science, and chemical engineering. Through similarity transformation, governing partial differential equations simplify into ordinary differential equations. Precise computational solutions are derived using the Nachtsheim-Swigert shooting iteration method (NSSIM) and the reliable 6th-order Runge-Kutta integration algorithm (RKIA). The profiles of velocities, temperatures, concentrations, skin friction, heat and mass transfer rate are presented by graphically. The novel aspect of this research is that thermal performance is enhanced by non-linear radiation by around 2.28%, whereas linear radiation only produces a 0.28% improvement in thermal performance. Also the mass transfer rate experiences a decrease of about 25.76% with increasing chemical reactions in the presence of activation energy and a more substantial 62.22% reduction in its absence, notably showing a comparatively milder decline of 36.46% in the presence of activation energy than in its absence. Furthermore, this study yields three novel linear regression equations, skillfully derived from the numerical and graphical results. This research have practical applications in understanding and optimizing processes involving fluid dynamics, such as the behavior of certain materials or substances subjected to stretching or deformation.

Mechanochemical and Microwave Multistep Organic Reactions

Abstract: The development of more sustainable chemical reactions and processes has been the focus of recent research activities. Advances in the field of organic synthesis have led to the emergence of new methodologies and techniques involving non-conventional energy sources. These include the applications of mechanical energy (mechanochemistry) and microwave radiation (MW) methods. This article reviews the advances in multistep organic synthesis of biologically relevant organic molecules using mechanochemistry and microwave techniques. Among them, various heterocyclic molecules (with nitrogen, oxygen, and sulphur atoms), amides, and peptides have been synthesized by multistep mechanochemical or MW reactions. Performing multiple synthetic steps using more sustainable methods shows cumulative advantages over multistep processes under conventional conditions in terms of reduced solvent use, shorter reaction times, better turnovers, and reaction yields. Simplification of protocols by carrying out two or more reaction steps in the same reaction vessel is another advantage of multistep syntheses.

Atomic Electrostatic Potential as a Descriptor of Aminolysis of Phenyl and Thiophenyl Acetates and Hydrolysis of Acetanilides

Abstract: Hydrolysis of acetanilides and aminolysis of phenyl and thiophenyl acetates are related reactions since these are processes of nucleophilic substitution on the carbonyl carbon. Current views of chemical reactivity based on the DFT theory rely upon reactivity indices that are descriptors of both the reaction center and the molecule as a whole, and have not been applied to the given processes before. One of such descriptors is an atomic electrostatic potential. The given parameter was calculated by the DFT theory M06/6-311+G (non-specific solvation, MeCN, SMD, and full optimization) for the structures of substituted phenyl acetates XPhO-C(O)Me, acetanilides XPhNHC(O)Me, thiophenyl acetates ZPhSC(=O)Me, and benzyl amines XPhСH2NH2 (X, Z substituents). It has been found that all relationships between the atomic electrostatic potential, the charge on the reaction center in the Hirshfeld scheme, and logK are symbatic. Consequently, in all of the cases, the rate is determined by the nucleophilic attack on the reaction center, with the activity/selectivity relationship being observed. The fact that the reaction rate is limited by the nucleophilic attack of the reagent is not inconsistent with the views of the reaction being concerted, since it is known that such reactions may be quite concerted though not quite synchronous.

Study on Sustainable Resource Utilization as Ligand Precursors in Coordination Chemistry

Ligand Precursors in Coordination Chemistry.” Sustainable resource utilization in ligand precursor synthesis is crucial for advancing green chemistry principles and addressing environmental concerns in coordination chemistry. This study investigates the feasibility and efficacy of utilizing renewable resources as precursor materials for ligand synthesis, aiming to reduce environmental impact while maintaining the efficacy and versatility required in coordination chemistry applications. Through a combination of synthetic organic chemistry and coordination chemistry techniques, novel ligand precursors derived from sustainable sources were synthesized and characterized. Various renewable feedstocks, including biomass-derived compounds and waste materials, were explored as potential starting materials for ligand precursor synthesis. Optimization of synthetic routes and reaction conditions led to the development of efficient protocols for the synthesis of sustainable ligand precursors. Characterization techniques such as nuclear magnetic resonance spectroscopy, mass spectrometry, and infrared spectroscopy were employed to confirm the structures and purities of synthesized ligand precursors. Evaluation of the performance of sustainable ligand precursors in coordination chemistry reactions demonstrated their ability to form stable complexes with metal ions and exhibit catalytic activity in relevant reactions. Comparative studies with traditional ligands revealed the environmental advantages of sustainable ligand precursors, including reduced energy consumption, greenhouse gas emissions, and solvent usage. Overall, this study highlights the importance of sustainable resource utilization in ligand precursor synthesis for promoting environmentally friendly practices in coordination chemistry and advancing the principles of green chemistry.

Photoinitiated Transient Self-Assembly in a Catalytically Driven Chemical Reaction Cycle.

Chemically-fueled chemical reaction networks (CRNs) are key in controlling dissipative self-assembly. A key challenge in the field is to store chemical fuel-precursors or "pre-fuels" in the system that are catalytically converted into activating or deactivating fuels that drive the CRN. In addition, real-time control over such catalysis by light is highly desirable, but so far not yet achieved. Here we show a catalytically-driven CRN that is photoinitiated with 450 nm light, producing activated monomers that go on to perform transient self-assembly. Monomer activation proceeds via photoredox catalysis, converting the monomer alcohol groups into the corresponding aldehydes that self-assemble into large supramolecular fibers. Monomer deactivation is achieved by organometallic catalysis that relies on pre-fuel hydrolysis to release formate (i.e., the deactivating fuel). Additionally, irradiation with 305 nm light accelerates the release of formate by photo-uncaging the pre-fuel, leading to a factor ~2 faster deactivation of the monomer. Overall, we show transient self-assembly upon visible light photoactivation, and tunable life-times by ultraviolet light.

Mixed Matrix Pt-Carbon Nanofiber Polyethersulfone Catalytic Membranes for Glucose Dehydrogenation.

The advancement of technologies for producing chemicals and materials from non-fossil resources is of critical importance. An illustrative example is the dehydrogenation of glucose, to yield gluconic acid, a specialty chemical. In this study, we propose an innovative production route for gluconic acid while generating H2 as a co-product. Our concept involves a dual-function membrane, serving both as a catalyst for glucose dehydrogenation into gluconic acid and as a means to efficiently remove the produced H2 from the reaction mixture. To achieve this two membranes were developed, one catalytically active and one dense aimed at H2- removal. The catalytic membrane showed significant activity, yielding 16% gluconic acid (t=120 min) with a catalyst selectivity of 93% and stable performance over five consecutive cycles. Incorporating the H2 separating membrane showed the significance of H2 removal in driving the reaction forward. Its inclusion led to a twofold increase in gluconic acid yield, aligning with Le Chatelier's principles. As a future prospect the two layers can be combined into a dual-layer membrane which opens the way for a new production route to simultaneously produce gluconic acid and H2, using high-throughput reactors such as hollow-fiber systems.

Reactive direct simulation Monte Carlo modeling of gas reactive transport in three dimensional porous fibrous media across rarefied to continuum regimes

Gas flow in complex porous media can vary across rarefied to continuum regimes depending on the characteristic size of porous media. To study the gas reactive transport process in three dimensional porous fibrous media across rarefied to continuum regimes, a comprehensive reactive direct simulation Monte Carlo model coupling with heat conduction and radiation model as well as reaction process is proposed. The results calculated by the proposed model are verified to fit well with those obtained using analytical model and experimental data. The “inlet” effect promoting the skeleton temperature is found. There are existing competitions between the heat conduction, reaction rate and convection, radiation process. The temperature of porous fibrous media skeleton increases with the catalyst coverage, and decreases with increase of Knudsen number. When the proportion of hydrogen increases, the increase in the temperature of the porous fibrous media skeleton is initially rapid and then gradual. These studies help to deeply understand the chemical reaction mechanism in porous media across rarefied to continuum regimes.

Investigation of the Proton-Bound Dimer of Dihydrogen Phosphate and Formate Using Infrared Spectroscopy in Helium Droplets.

Understanding the structural and dynamic properties of proton-bound complexes is crucial for elucidating fundamental aspects of chemical reactivity and molecular interactions. In this work, the proton-bound complex between dihydrogen phosphate and formate, and its deuterated counterparts, is investigated using IR action spectroscopy in helium droplets. Contrary to the initial expectation that the stronger phosphoric acid would donate a proton to formate, both experiment and theory show that all exchangeable protons are located in the phosphate moiety. The experimental spectra show good agreement with both scaled harmonic and VPT2 anharmonic calculations, indicating that anharmonic effects are small. Some H-bending modes of the nondeuterated complex are found to be sensitive to the helium environment. In the case of the partially deuterated complexes, the experiments indicate that internal dynamics leads to isomeric interconversion upon IR excitation.

Dynamics of carbene formation in the reaction of methane with the tantalum cation in the gas phase.

The controlled activation of methane has drawn significant attention throughout various disciplines over the last few decades. In gas-phase experiments, the use of model systems with reduced complexity compared to condensed-phase catalytic systems allows us to investigate the intrinsic reactivity of elementary reactions down to the atomic level. Methane is rather inert in chemical reactions, as the weakening or cleavage of a C-H bond is required to make use of methane as C1-building block. The simplest model system for transition-metal-based catalysts is a mono-atomic metal ion. Only a few atomic transition-metal cations activate methane at room temperature. One of the most efficient elements is tantalum, which forms a carbene and releases molecular hydrogen in the reaction with methane: Ta+ + CH4 → TaCH2+ + H2. The reaction takes place at room temperature due to efficient intersystem crossing from the quintet to the triplet surface, i.e., from the electronic ground state of the tantalum cation to the triplet ground state of the tantalum carbene. This multi-state reactivity is often seen for reactions involving transition-metal centres, but leads to their theoretical treatment being a challenge even today. Chemical reactions, or to be precise reactive collisions, are dynamic processes making their description even more of a challenge to experiment and theory alike. Experimental energy- and angle-differential cross sections allow us to probe the rearrangement of atoms during a reactive collision. By interpreting the scattering signatures, we gain insight into the atomistic mechanisms and can move beyond stationary descriptions. Here, we present a study combining collision energy dependent experimentally measured differential cross sections with ab initio calculations of the minimum energy pathway. Product ion velocity distributions were recorded using our crossed-beam velocity map imaging experiment dedicated to studying transition-metal ion molecule reactions. TaCH2+ velocity distributions reveal a significant degree of indirect dynamics. However, the scattering distributions also show signatures of rebound dynamics. We compare the present results to the oxygen transfer reaction between Ta+ and carbon dioxide, which we recently studied.

REME: an integrated platform for reaction enzyme mining and evaluation.

A key challenge in pathway design is finding proper enzymes that can be engineered to catalyze a non-natural reaction. Although existing tools can identify potential enzymes based on similar reactions, these tools encounter several issues. Firstly, the calculated similar reactions may not even have the same reaction type. Secondly, the associated enzymes are often numerous and identifying the most promising candidate enzymes is difficult due to the lack of data for evaluation. Thirdly, existing web tools do not provide interactive functions that enable users to fine-tune results based on their expertise. Here, we present REME(https://reme.biodesign.ac.cn/), the first integrated web platform for reaction enzyme mining and evaluation. Combining atom-to-atom mapping, atom type change identification, and reaction similarity calculation enables quick ranking and visualization of reactions similar to an objective non-natural reaction. Additional functionality enables users to filter similar reactions by their specified functional groups and candidate enzymes can be further filtered (e.g.by organisms) or expanded by Enzyme Commission number (EC) or sequence homology. Afterward, enzyme attributes (such as kcat, Km, optimal temperature and pH) can be assessed with deep learning-based methods, facilitating the swift identification of potential enzymes that can catalyze the non-natural reaction.

Biodegradable material for glaucoma drainage devices - A pilot study in rabbits.

To study the morphological and histological characteristics of the fibrous capsule formed around a novel biodegradable glaucoma drainage device (GDD) implant made of oxidized regenerated cellulose (ORC) after 1 and 3 months of its implantation. It was a prospective, interventional, preclinical experimental study using New Zealand white rabbits. All animals underwent GDD implantation with a novel biodegradable device. The device's body was made of ORC and attached to a silicone tube, connecting the body to the anterior chamber. Histopathology (hematoxylin and eosin/Masson's trichrome staining) and immunohistochemistry (Alpha-Smooth Muscle Actin expression) characteristics of the bleb formed around the novel device were noted at 1 and 3 months. One month post implantation, the biodegradable material produced a significant foreign body type of reaction evidenced by the exuberant infiltration by macrophages, lymphocytes, and multinucleated giant cells. The granulomatous response subsided by 3 months with disorganized collagen deposition on Masson's trichrome staining. The silicone tube was an internal control, and histopathology demonstrated well-organized collagen deposition around it at 3 months. Immunohistochemistry for α-smooth muscle actin also demonstrated more myofibroblast transformation at the site of the tube than the biodegradable implant. Our results indicate that the tissue response around a biodegradable GDD was different from the response to conventional devices. A diffuse, loose vascularized mesh was observed to develop, which may be more compatible with sustained IOP control over a longer period, in contrast to the usual thick and dense capsule formed around the non-biodegradable devices.

Quantum Chemical Study of the Production of 1-Vinyladamantane As a Result of Ionic Alkylation of Adamantane with Ethylene

Abstract A multi-stage process is considered for the formation of vinyl adamantane via the ionic alkylation of adamantane with ethylene using aluminum chloride as a catalyst. A feature of the ionic alkylation of adamantane with olefins is the formation of saturated and unsaturated derivatives. Quantum chemical methods means are used to study the kinetic and thermodynamic parameters of the corresponding elementary acts of chemical reactions. A comparative analysis of the characteristics of the reaction for the production of unsaturated adamantane derivatives via ionic alkylation with ethylene is performed using alkylation with propylene.

Kinetic analysis for the interpretation of polychlorinated biphenyls removal mechanism

AbstractRemoving polychlorinated biphenyls (PCBs) from subsurface water, soils, and transformer oil is crucial to save the environment from these pollutant materials. Hydrodechlorination (HDC) of PCBs consists of numerous chemical reactions and the simple kinetic models may not provide details for the process. To gain more awareness of the reaction mechanism, in the proposed approach, the isoconversional methods of the Friedman were investigated paralleling other kinetic models of Langmuir‐Hinshelwood (L‐H), Eley‐Rideal (E‐R), pseudo‐first‐order, and pseudo‐second‐order methods. The analysis was validated by laboratory results of HDC of contaminated transformer oil in front of Pd/MWCNTs. The most reactivity was observed for biphenyls with a higher number of chlorines. Finding a suitable model, Akaike Information Criteria were applied. It was attained that Friedman model was the most suitable for monitoring of HDC of PCBs in front of catalyst. Besides, E‐R reaction was appropriate to elucidate the theoretical interpretations of the adsorption and desorption of reactants and chlorinated benzene.

Firing salts method for the synthesis of orthorhombic Gd2TiO5: experimental characterization supported by DFT first principles calculations

Abstract This work presents the synthesis by the new “firing salts method” (FSM) of orthorhombic Gd2TiO5 which requires only two hours at 1200 ºC. X Ray Diffraction, High Resolution Transmission Electron Microscopy, Fourier Transform Infrared Spectroscopy and Raman spectroscopy characterized it. Electron microscopy shows particle size distribution between 50 – 500 nm with orthorhombic structure according to Rietveld analysis. Raman – infrared spectroscopies and first principles calculations indicate that the second order contribution to the spectra comes from the Ti-O5 interactions. First principles calculations (Density Functional Theory) were used as an aid for the interpretation of the experimental results to assign the normal modes to the bands on the Raman and IR spectra; it also provided an insight of the chemical reactivity of the synthesis.

Rhodium(I)-Catalyzed Annulation of Bicyclo[1.1.0]butyl-Substituted Dihydroquinolines and Dihydropyridines.

Bicyclo[1.1.0]butane-containing compounds feature a unique chemical reactivity, trigger "strain-release" reaction cascades, and provide novel scaffolds with considerable utility in the drug discovery field. We report the synthesis of new bicyclo[1.1.0]butane-linked heterocycles by a nucleophilic addition of bicyclo[1.1.0]butyl anions to 8-isocyanatoquinoline, or, alternatively, iminium cations derived from quinolines and pyridines. The resulting bicyclo[1.1.0]butanes are converted with high regioselectivity to unprecedented bridged heterocycles in a rhodium(I)-catalyzed annulative rearrangement. The addition/rearrangement process tolerates a surprisingly large range of functional groups. Subsequent chemo- and stereoselective synthetic transformations of urea, alkene, cyclopropane, and aniline moieties of the 1-methylene-5-azacyclopropa[cd]indene scaffolds provide several additional new heterocyclic building blocks. X-ray structure-validated quantum mechanical DFT calculations of the reaction pathway indicate the intermediacy of rhodium carbenoid and metallocyclobutane species.

Effect of metakaolin content and shape design on strength performance of lightweight rubberized geopolymer mortars incorporated slag-waste glass powders

Lightweight rubberized geopolymer (LRGP) has gained attention due to its economic, engineering, and environmental benefits. With the rising human demands, the need for alternative materials to meet the requirements of infrastructural expansion, and global industrialization required. Based on those facts, this study aimed to develop of lightweight geopolymer mortars using wastes rubber as fine aggregate (WRA) to replace the natural aggregates, which metakaolin (MK), wastes bottle glass (WBG) and granulated blast furnace slag (GBFS) used as precursor materials with alkaline activator contained low molarity of sodium hydroxide solution and sodium silicate and cured at ambient temperatures. The effect of WRA on physical, mechanical, and microstructural properties of metakaolin-based rubberized geopolymer has been evaluated by using several tests such as compressive, flexural and tensile strength. As well as morphology and chemical reaction on LRGP by using AFM, FESEM, EDX, FTIR and XRD tests. In addition, a sustainable shape design has been cast and subjected to compressive strength to obtain the strength performance of the proposed LRGP mortar. At optimal mixture, the SEM images exhibited improvement in the interfacial transition zone (ITZ) among WRA and binder, leading rubberized geopolymer with 15% WRA to achieve a strength of 27.47 MPa after 28 days and with a reduction in density by 7.2%. The findings of this study can provide valuable insights on utilizing WRA in the shape design and formulation of geopolymer mortar, a key ingredient in the development of functional environmentally friendly building materials.