Organic Modifier Research Articles

Spectrometric monitoring of CO2 electrolysis on a molecularly modified copper surface.

Since copper has been extensively studied due to its unique ability to reduce carbon dioxide to hydrocarbons and alcohols, it tends to yield a mixture of products. Among various efforts to improve the selectivity and efficiency of this catalysis, the introduction of organic molecules and polymers on the copper/electrolyte interface has proven to be an effective and promising way to improve surface activity, considering the variation and precise designability of organic structures. The role of surface molecular modifiers, however, is not as simple as that in homogeneous catalysts, and an understanding of a wide scale of interactions from the atomic scale to the whole electrode structure is required. This feature article classifies those different scale interactions caused by organic modifiers on copper catalysts, together with the experimental support by in situ vibrational spectroscopy which directly observes surface species and events. Based on these recent understandings, novel fabrication methods of organic structures on copper catalysts are also discussed.

Palladium particle-catalyzed selective butadiene hydrogenation: effect of covalent organic framework modification

Deposition of a covalent organic framework on palladium nanoparticles induces geometric and electronic effects on the metal species and improves their selective performance in 1,3-butadiene hydrogenation.

Analytical method development and validation of antifungal drugs in updated ointment formulation using UV spectroscopy and RP-HPLC

A precise, simple, and validated Reverse-phase high-performance liquid chromatography (RP-HPLC) method alongside spectrophotometric analysis has been established for the simultaneous quantification of clobetasol propionate, miconazole nitrate, and salicylic acid in an updated ointment formulation. The impact of organic modifiers on the retention of the target compounds was assessed. The chromatographic analysis was conducted using a simple low-pressure gradient method with UV detection at 282 nm on a C18 column (5 ?m, 4.6 ? 250 mm HSS). The mobile phase consisted of a mixture of methanol, acetonitrile, and tetra ethylamine acetate buffer at pH 4, adjusted with acetic acid in a 40:40:20 v/v ratio, at a flow rate of 1.2 mL min-1. The method demonstrated linearity in the 5-15 ?g mL-1 concentration range for clobetasol propionate, 30-90 ?g mL-1 for miconazole nitrate, and 15-45 ?g mL-1 for salicylic acid. The limits of detection and quantification were determined to be 1.49 ?g mL-1 and 4.53 ?g mL-1 for clobetasol propionate, 8.72 ?g mL-1 and 26.43 ?g mL- 1 for miconazole nitrate, and 3.37 ?g mL-1 and 10.22 ?g mL-1 for salicylic acid, respectively. The recoveries for drugs in formulation range from 95 % to 99 %.

Evaluation of surface organic layered double hydroxides on the anti-ageing performance of asphalt

To promote the anti-ageing performance of asphalt, layered double hydroxides (LDHs) modified by propyl trimethoxylsilane (MPMS) was prepared and applied to modify asphalt. Fourier transform infrared spectroscopy (FTIR) showed that MPMS was chemically-grafted on the surface of LDHs. The interaction between LDHs and asphalt was significantly enhanced after MPMS organic modification, and MPMS organic LDHs (OMLDHs) exhibited better compatibility in asphalt. OMLDHs and LDHs could enhance the high-temperature properties of asphalt, particularly OMLDHs. After ageing, the properties and structure of asphalt were dramatically degenerated. The incorporation of LDHs could inhibit the oxygenic groups increase in asphalt molecules during ageing, and retard the gelatinization of colloidal structures. LDHs could alleviate the negative effect of ageing on asphalt, and improve the anti-ageing performance of asphalt. The improvement effectiveness of LDHs on the anti-ageing performance of asphalt was remarkably improved after MPMS modification.

Organic Modification of Silica-Based Ionogels Improves the Electrolyte/Electrode Contact and Influences Their Functional Properties

The energy transition necessitates sustainable energy storage to address the mismatch between the production and consumption of renewable electricity. Sodium-ion batteries (SIBs) are a promising candidate for stationary energy storage as an alternative for lithium-ion batteries (LIBs). In spite of their lower energy density, SIBs have advantages over LIBs.1 Sodium is considerably more abundant than lithium (2.83% versus 0.01%) and, evenly distributed across the Earth, implying that SIBs may be less expensive and more sustainable than LIBs.1,2 Conventional LIBs contain flammable organic liquid electrolytes (e.g. alkyl carbonates) with limited thermal stability. Thermal runaway can therefore lead to cell ignition, causing a significant safety hazard. Non-flammable electrolytes can be based on ionic liquids, which are molten salts with flame retarding properties and negligible vapor pressures. However, the possibility of leakage and related environmental hazards remains a concern.3 This risk can be mitigated by the use of solid electrolytes. Apart from circumventing safety issues, solid electrolytes may allow a significant increase in energy density. After all, they take up less dead volume than liquid electrolytes and can allow the use of alkali metals as negative electrodes.An attractive type of solid electrolyte is the class of silica-based ionogels, owing to their high ionic conductivity, thermal stability, and broad electrochemical window.4 They comprise an ionic liquid electrolyte (ILE, a salt dissolved in ionic liquid) confined in the pores of a solid silica matrix. The silica matrix is electrochemically inactive but influences the functional properties of the resulting solid material. Ionogels based on solely silica (SiO2) as matrix tend to crack easily when subjected to pressure as the rigid Si-O-Si bonds result in high Young’s modulus materials. Furthermore, materials with high Young’s moduli cannot adapt easily to electrode surfaces, resulting in higher charge-transfer resistances (Rct) between the solid electrolyte and electrode. One way to reduce the stiffness of silica-based ionogels is to modify the silica matrix with e.g. organic groups. Ormosils® are a class of materials completely consisting of organically modified silica and show mechanical properties from glassy to rubbery depending on the amount of organic modification.5 Here, the concepts of ionogels and Ormosils® are combined to produce sodium-ion conducting organically modified ionogels. Two different phenyl-bearing silanes (phenyltrimethoxysilane, PhTMS, or diphenyldimethoxysilane, DPhDMS) are for the first time used as organic modifiers in silica-based ionogels. A non-aqueous sol-gel route with formic acid (FA) is used to synthesize the monoliths. Incorporating phenyl groups allow to reduce the Young’s modulus from 29 MPa down to 6 MPa. The charge-transfer resistances (Rct) of Na|ionogel|Na2Ti3O7 half cells, determined with electrochemical impedance spectroscopy (EIS), followed the trend of the ionogels’ Young’s modulus. Through NMR spectroscopy, pi-stacking was observed between the matrix phenyl moieties and IL imidazolium cations. Furthermore, the organic modification diminished the formation of hydrogen bonds between IL anions and matrix silanol groups. This shows that the organic modification of the matrix can have a pronounced effect on the coordination of the ILE components, which ultimately determine the solid electrolyte’s functional properties. In summary, incorporating phenyl groups in the silica matrix of ionogels improves the mechanical properties and charge transfer resistances, but impairs ionic conductivity. Acknowledgments: This research is made possible by the Research Foundation Flanders (FWO, project G053519N and 1S08921N) and the Special Research Fund (BOF) of Hasselt University (BOF20INCENT19). This work is further supported by Hasselt University and FWO Vlaanderen via the Hercules project AUHL/15/2 - GOH3816N.

Improved Electrical Properties of Organic Modified Thermoplastic Insulation Material for Direct Current Cable Application.

To achieve exceptional recyclable DC cable insulation material using thermoplastic polypropylene (PP), we have introduced the organic polar molecule styrene-maleic anhydride copolymer (SMA) into PP-based insulation materials following the principles of deep trap modification. PP, PP/SMA, PP/ethylene-octene copolymer (POE), and PP/POE/SMA insulating samples were prepared, and their meso-morphology, crystalline morphology, and molecular structure were comprehensively characterized. The results indicate that SMA can be uniformly dispersed in PP with minimal impact on the crystalline morphology of PP. The DC electrical properties of the materials were tested at temperatures of 30, 50, and 70 °C. The findings demonstrate that the introduction of SMA can improve the DC properties of the material in both PP and PP/POE. The thermal stimulated depolarization current results reveal that SMA can introduce deep traps into the material, thereby improving its DC properties, which is in agreement with the quantum chemical calculation results. Subsequently, a bipolar carrier transport model was employed for coaxial cables to simulate the space charge distribution in the insulation layer of the four sets of insulation samples as well as the actual cable in service. The results highlight that SMA can significantly suppress space charge in PP and PP/POE systems, and it exhibits excellent electric field distortion resistance. In summary, the results illustrate that SMA is expected to be used as an organic deep trap modifier in PP-based cable insulation materials.

Self-Repairing Ability of Hybrid Cobalt Hydroxide Nanosheets As Oxygen Evolution Catalysts in Alkaline Electrolytes

Introduction Water electrolysis is a key technology to produce H2 from renewable energy. Because proton exchange membrane water electrolyzers (PEMWE) require noble metals as catalysts, alkaline-type electrolyzers, such as alkaline water electrolyzers (AWE) and anion exchange membrane water electrolysis (AEMWE), have attracted much attention for the use of nonnoble-metal-based catalysts. One of the most important issues of AWE is the degradation of catalysts due to generation of reverse current upon shutdown and power fluctuation. Reverse current hardly generates in AEMWE in principle; however, it possibly generates if an electrolyte is supplied instead of pure water.We have previously reported the self-repairing anode catalysts for AWE [1, 2]. A hybrid cobalt hydroxide nanosheet (denoted as Co-ns, Figure 1a), a Brucite-type cobalt hydroxide modified with tripodal ligands (tris(hydroxymethyl)aminomethane), was dispersed in an alkaline electrolyte. Co-ns is deposited on the anode during the electrolysis at 800 mA/cm2 to form a catalyst layer. After the degradation of the catalyst by potential cycling, Co-ns is deposited to retain the catalytic activity. To develop catalysts with higher activity, durability, and repairing ability, the understanding of the electrochemical deposition of Co-ns is quite important. Here, we demonstrate the mechanism of the electrochemical deposition of Co-ns.ExperimentalCo-ns was synthesized according to our previous report [1]. The Co-ns was dispersed in 1 M KOH electrolyte at varied concentrations of Co-ns. Ni electrodes were used as both working and counter electrodes. Reversible hydrogen electrode (RHE) was used as a reference. Constant current electrolysis at 800 mA/cm2 was applied for 30 min, followed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to evaluate the oxygen evolution reaction (OER) activity and the amount of deposited Co. These processes ware repeated for several times to characterize the deposition behaviors. Similar experiments were performed, using Co(OH)2 or CoOOH instead of Co-ns.Results and DiscussionCo-ns was transformed into CoOOH by the decomposition of the tripodal ligand. The deposited amount of Co was evaluated by CV, in which the charge of the cathodic currents at 0.8–1.6 V vs. RHE (denoted as Q c) was proportional to the amount of Co measured by ICP-AES. Figure 1b shows the plots of Q c vs. duration of electrolysis. The amounts of deposited CoOOH depended on the concentration of Co-ns. The deposition rates (slope of the curves) gradually decreased along with the progress of the catalyst deposition. During the electrolysis, the electrode potential decreased because of the increased OER activity due to the catalyst deposition. Assuming that the deposition of CoOOH is a pseudo first-order reaction, its rate constant was calculated by dividing the deposition rate by the concentration of Co-ns. The rate constants are linearly correlated with the electrode potential (Figure 1c); thus, the deposition was confirmed to be an electrochemical process. The present results mean that the electrochemical deposition of CoOOH is accelerated when the electrode potential increases due to the degradation of catalysts. Therefore, the self-repairing process is automatically controlled by the condition of the electrode.The electrochemical deposition proceeds with Co(OH)2, whereas CoOOH hardly deposited at the same conditions, indicating that the oxidation of Co2+ to Co3+ is an essential step of the electrochemical deposition. The electrochemical deposition of Co(OH)2 was stopped after 60 min of electrolysis because of the autooxidation of Co(OH)2 by dissolving O2. It was shown that Co-ns is stable in an electrolyte saturated with O2 probably because the organic modification suppresses the autooxidation. Thus, it is shown that the organic modification of cobalt hydroxide is crucial to retain the self-repairing ability in an electrolyzer.ConclusionIn conclusion, the potential dependence of the rate constant and the essential step of electrochemical deposition of Co-ns were elucidated through systematic studies using Co-ns and related metal hydroxide catalysts. These findings lead to the design of self-repairing electrocatalysts with high activity, long lifetime, and high self-repairing ability using organic functionalization.Acknowledgement This work was supported by the JSPS KAKENHI (grant number 20H02821). Part of this study uses outcomes of the development of fundamental technology for the advancement of water electrolysis hydrogen production in the advancement of hydrogen technologies and utilization projects (grant number JPNP14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO) in Japan.

Solidification of a Silica-Based Solid Composite Electrolyte for Lithium-Ion Batteries Induced By UV Irradiation

The use of solid electrolytes in lithium-ion batteries (LIBs) instead of their liquid counterparts may significantly increase their energy density. Of particular interest are solid composite electrolytes (SCEs) which can be synthesized by incorporating ionic liquids (ILs, salts with a melting point lower than 100 °C) into a solid matrix. This class of SCE can have a wide electrochemical stability window and is typically non-flammable.Chen et al.1 developed an SCE with excellent ionic conductivity, consisting of a mesoporous silica monolith which encloses an IL electrolyte (solid nanocomposite electrolyte or nano-SCE). It is formed from a precursor solution which does not contain acids such as formic acid or HCl, meaning that it can be impregnated into porous electrodes without causing damage to the latter. However, its gelation process is long and variable (5-9 days), and is considerably affected by its presence within the electrode. As such, the nano-SCE has poor manufacturability and is not compatible with the continuous roll-to-roll processing typically used for LIB manufacturing. The manufacturability of the nano-SCE can be significantly improved by making its solidification process instantaneous upon subjection to an external trigger.As such, organic modification was used to produce silica-based precursor solutions capable of triggered solidification, for instance by irradiation with UV light. This solidification process takes a few minutes to complete and does not depend on pH, rendering it particularly versatile. The aging of the precursor solutions was studied with 29Si, 1H, and 13C NMR spectroscopy, which revealed that the alkoxysilane precursor molecules condensed into larger soluble structures over the course of five weeks. The aged precursor solutions remained stable over an indefinite period of time. When a photo-initiator is added to these solutions and they are irradiated with UV light, the soluble structures are linked together, resulting in the formation of silica nanoparticles which subsequently aggregate into a porous matrix which encapsulates the ionic liquid electrolyte (ILE).The adaptation does not compromise the functional properties such as ionic conductivity or electrochemical stability. As determined with Raman spectroscopy, the extent of organic modification and amount of ILE can be optimized to decrease the interaction of lithium ions with the other ions as compared to the neat ILE. The increased Li+ mobility means that the SCE can reach higher ionic conductivity (2.7 mS cm-1 at 20 °C) values than the neat ILE (2.5 mS cm-1). Anodic and cathodic linear sweep voltammetry in three-electrode cells was performed to determine that the SCEs can have an electrochemical stability window exceeding 5 V (i.e. lithium plating < 0 vs Li+/Li and electrolyte oxidation > 5.0 V vs Li+/Li). Electrochemical impedance spectroscopy further confirmed the SCE’s compatibility with lithium metal. As no acids are added to the precursor solution, a good electrode compatibility is expected. As such, the precursor solutions were impregnated into NMC622-based electrodes, solidified, and incorporated in half cells. These cells had an initial discharge capacity of 162 mAh g-1 at 0.1 C, retaining 86.8% of this capacity after 100 cycles.This work was supported by funding from the European Union’s Horizon 2020 research and innovation program for the Solidify project under grant agreement No. 875557.(1) Chen, X.; Put, B.; Sagara, A.; Gandrud, K.; Murata, M.; Steele, J. A.; Yabe, H.; Hantschel, T.; Roeffaers, M.; Tomiyama, M.; et al. Silica Gel Solid Nanocomposite Electrolytes with Interfacial Conductivity Promotion Exceeding the Bulk Li-Ion Conductivity of the Ionic Liquid Electrolyte Filler. Sci. Adv. 2020, 6 (2). https://doi.org/10.1126/sciadv.aav3400.

Atomic Layer Deposition for Quantum Dots Displays’ Devices Stabilization

As display plays an increasingly important role in people's life, from mobile phones, automobile displays to AR, VR and 3D naked eye screens. There are increasing demands for pursuing higher resolution, refresh frequency, wider color gamut, etc. Therefore, photoluminescence materials with excellent photoelectric performance have attracted broad attention, but there are still some problems in their application, and achieving higher performance with stability is still urgent to be solved. Atomic layer deposition (ALD) has been developed as an attractive method to modify and stabilize photoluminescence materials. For photoluminescence PL performance, the stabilization of crystal structure can be achieved by solution treatment, and the luminescence performance can be improved. ALD was performed to enhance the stability of CsPbBr3 quantum dots in light, water and heat, which originated from the surface defects passivation. The combined method of organic hydrophobic surface modification and ALD infiltration is used to construct a dual-shelled to prevent the crystal deformation and ligand desorption of luminescent materials, and is also applicable to phosphor materials. For electroluminescence EL performance, ALD modification methods were developed for the light-emitting layer modifying, gas phase ALD and colloidal ALD were developed to decreasing the transport barrier between the quantum dots, improve the carrier mobility of the device, and lift the EQE and stability of the device. In addition, ultrathin film grow through ALD could effectively balance the carrier and improve the recombination efficiency as well as important functional layers. ALD of dual Electron transport layers(ETLs) and dual hole injection layers(HILs) is developed to enhance luminance performance of the PQLEDs but also achieve a long lifetime under constant voltage. Our works provide a versatile method for preparing ultra stable photoluminescence materials through ALD and significantly improve their potential in LED illumination and displays.

Synergistic lubrication mechanism of nanodiamonds with organic friction modifier

Nanoparticles and organic friction modifiers (OFMs) as lubricant additives have shown great potential in friction and wear reduction by forming tribofilms which prevent direct contact at the sliding interface. Potential mechanisms for the formation of these tribofilms remain poorly understood, limiting the ability to optimise the performance of the entire tribosystem. Incorporation of nanoparticles and OFM together in a lubricant could provide a unique solution to enhance frictional and wear properties. In this study, Nanodiamonds (NDs) and Glycerol Monooleate (GMO) have been added to a PAO base oil containing low concentration of Zinc dialkyl dithio-phosphate (ZDDP) to produce a novel lubricant combination that significantly reduces coefficient of friction (COF) and wear. Experimental studies showed that NDs reacted with additives present in the lubricant combination to expedite tribofilm formation. Friction reduction performance can be attributed to the encapsulation of carboxylated NDs due to tribochemical interaction with GMO, their mechanical interlocking in the tribofilm and polishing effect of NDs. The visible presence of NDs in tribofilms and the formation of a thicker tribofilm layer with NDs have been corroborated for the first time in this study. Synergy achieved among NDs, GMO, and low concentration ZDDP to formulate a novel environmentally friendly lubricant with advanced tribological performance has been shown, providing a great potential to develop sustainable tribological solutions for a wide variety of engineering applications.

ANALYSIS OF PROSPECTS FOR THE USE OF LOCAL RAW MATERIALS FOR THE PRODUCTION OF SELF-SEALING CONCRETES IN THE REPUBLIC OF KAZAKHSTAN

Initiation of production and application of self-compacting concrete (SCC) in Kazakhstan requires not only local research within the framework of solving technological problems in one agglomeration under active construction, but also an assessment of potential opportunities for the development of the raw material base of SBC and processing industries in different regions. Taking into account that the raw material possibilities for these purposes in the regions of Kazakhstan differ to a great extent, and the considered type of concrete is economically feasible only when using local raw materials in the composition, the conceptual approaches to the selection and evaluation of raw materials for SCC, known in the world scientific practice, were analyzed and summarized. as well as the results of the development of SCC in KazGASA with the use of raw materials relevant for a number of regions. Studies of local raw materials have shown the prospect of using high-silica furnaces in high-strength substations; fillers from the screenings of stone crushing of local rocks, represented by hydrothermally and metasomatically altered porphyrites of medium-major composition and porphyries of decrystallized quartz-feldspar composition; granites and hybrid rock of quartz diorite in composition with zeolite, microsilica. Issues requiring study were identified in the application of certain types of raw materials, which differ in mineralogical and other characteristics from those previously studied, issues in the development of own technology for the synthesis of organic modifiers for SCC.

Functionalization of Violet Phosphorus Quantum Dots with Azo-Containing Star-Shape Polymer for Optically Controllable Memory

Quantum dots (QDs) are emerging as promising candidates for innovative memristive materials, owing to their distinct surface, quantum size, and edge effects. Recent research has focused on tailoring QDs with specific organic molecules to fine-tune charge transfer states between the host and grafted species, as well as enhancing their dispersibility and processability. Violet phosphorus (VP), a newly discovered two-dimensional phosphorus allotrope, offers excellent carrier dynamics, predictable modifiability, and superior oxidation resistance, making it a promising contender in this domain. In this study, we synthesized a rich azobenzene-containing star-shaped polymer diazonium salt (AzoSPD) to functionalize violet phosphorus quantum dots (VPQDs), with the dual objectives of enhancing organic dispersibility and introducing photo-switching capabilities. The synthesized AzoSPD–VPQDs exhibit intramolecular charge transfer characteristics under electrical stimuli of ambient conditions, displaying significant non-volatile rewriteable memory properties and a substantial switching ratio exceeding 2 × 103. Furthermore, the high resistance state (HRS) current can be enhanced by nearly 40 times under 465 nm illumination, enabling optoelectronic information sensing and storage within a single device. This work not only provides insights into enhancing the optoelectronic properties of QDs through functional organic molecular modification but also represents a pioneering exploration of the potential applications of VPQDs in novel memristors.

Modification of gradient HPLC method for determination of small molecules' affinity to human serum albumin under column safety conditions: Robustness and chemometrics study

In the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity. Here, we proposed how to modify protocols presented by Valko into column safety conditions and evaluated their robustness using fractional factorial design. For robustness testing, four factors were selected: column temperature, mobile phase flow rate, maximum isopropanol concentration in the mobile phase, and buffer pH. Elaborate methods have been applied for the analysis of HSA affinity for three groups of antibiotic-oriented substances that vary in chemical structure: fluoroquinolones, sulfonamides, and tetrazole derivatives. Furthermore, based on the reversed-phase chromatography the workflow of pilot studies was proposed to select molecules that have high affinity to HSA and can not be eluted from the HSA column using the concentration of organic modifier recommended by the column manufacturer.

Development of a single mobile phase for LC-IM-MS-based discovery lipidomics and metabolic phenotyping: Application to methapyrilene hepatotoxicity in the rat

The untargeted global profiling of endogenous metabolites and lipids has the potential to increase knowledge and understanding in many areas of biology. LC-MS/MS is a key technology for such analyses however, several different LC methodologies, using different mobile phase compositions, are required to cover the diversity in polarity and analyte structure encountered in biological samples. Most notably many lipid screening methods make use of isopropanol (IPA) as a major component of mobile phases employed for comprehensive lipidomic profiling. In order to increase laboratory efficiency, and minimize opportunities for errors, a suite of methods, based on a single acetonitrile (ACN)-aqueous buffer mobile phase combination, has been developed. This mobile phase can be used for hydrophobic interaction liquid chromatography on an amide stationary phase (for polar analytes), reversed-phase (RP) LC analysis on a C8 stationary phase (for moderately polar-non-polar compounds) and RPLC using a CSH phenyl-hexyl bonded column (for lipids). All of these sub 10 minute separations had good throughput and reproducibility with CV's of analyte response <25 % whilst eliminating the need for complex mobile phase preparation and the use of IPA as an organic modifier for lipidomics. Advantages of removing IPA and replacing it with the ACN-based method were a 58 % increase in peak capacity for lipids, with improved resolution for the di- and triglycerides and cholesterol esters compared to current methods. Compared to the IPA-containing solvent system the ACN-based mobile phase also resulted in a 61 % increase in lipid feature detection. The utility of this “universal” mobile phase approach was demonstrated by its application to a rat toxicology study investigating the consequences of methapyrilene administration through on the endogenous metabolite profiles of plasma and urine. Methapyrilene and its metabolites were also profiled in these samples.

Modification Method of High-Efficiency Organic Bentonite for Drilling Fluids: A Review

The requirements for drilling bentonites are tightening due to ever-increasing demands for petroleum resources, coupled with cost and reaction technology constraints. In addition to raising the risk of drilling, bentonite’s poor performance also raises the possibility of safety incidents and significant financial losses. Organically modified bentonites effectively reduce the consumption of drilling fluids, conserve resources, and lessen environmental effects. This paper aims to provide an overview of the several organic modification methods of bentonite for drilling fluids. It also evaluates the characteristics and application impacts of bentonite. We primarily describe the three popular modification methods represented by intercalation, coupling, and grafting. Also, this review provides the effect of molecular simulation on the investigation of structure in microconfined conditions. Through microlearning, organically modified bentonite with exceptional performance is to be further developed.

A green HPLC method for the determination of torasemide in pharmaceutical dosage forms: Development, validation, and greenness assessment

Two HPLC methods were developed for the determination of torasemide in pharmaceutical products. In the first method, a C18 column whose temperature was kept constant at 25 °C was used. A combination of 0.1% formic acid solution in water and acetonitrile (50/50, v/v) was used as the mobile phase, and isocratic elution was performed at a flow rate of 1.0 mL min-1. Detection was carried out at 288 nm using the UV detector. Although all other conditions are the same as in the first method, the only difference in the second method is that ethanol is used instead of acetonitrile as the organic modifier in the mobile phase. HPLC methods were validated in accordance with ICH guidelines. Correlation coefficients were greater than 0.999 in the concentration range of 5-30 mg mL-1. Later, HPLC methods were applied to pharmaceutical formulations. Results were compared using the student (t) test for means and the Fischer (F) test for standard deviations. No significant differences were observed between methods. Additionally, a greenness evaluation of the developed methods was carried out using AGREE software. As a result, the latter method was proposed as an excellent eco-friendly alternative for the determination of torasemide in pharmaceuticals.&#x0D; KEY WORDS: Green HPLC, Analytical method, Torasemide, Pharmaceuticals&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2024, 38(1), 11-25. DOI: https://dx.doi.org/10.4314/bcse.v38i1.2

Electrical tunability of inorganic tin perovskites enabled by organic modifiers

Electrical tunability of inorganic tin perovskites enabled by organic modifiers

Dimethyl carbonate as a green alternative to acetonitrile in reversed-phase liquid chromatography. Part II: Purification of a therapeutic peptide

Preparative liquid chromatography in reversed phase conditions (RPLC) is the most common approach adopted in the downstream processing for the purification of therapeutic peptides at industrial level. Due to the strict requirements on the quality imposed by the Regulatory Agencies, routinary methods based on the use of aqueous buffers and acetonitrile (ACN) as organic modifier are commonly used, where ACN is practically the only available choice for the purification of peptide derivatives. However, ACN is known to suffers of many shortcomings, such as drastic shortage in the market, high costs and, most importantly, it shows unwanted toxicity for human health and environment, which led it among the less environmentally friendly ones. For this reason, the selection of a suitable alternative becomes crucial for the sustainable downstream processing of peptides and biopharmaceuticals in general.In this paper, a promising green solvent, namely dimethyl carbonate (DMC) has been used for the separation of a peptide not only in linear conditions but also for its purification through non-linear overloaded chromatography. The performance of the process has been compared to that achievable with the common method where ACN is used as organic modifier and to that obtained with two additional solvents (namely ethanol and isopropanol), already used as greener alternatives to ACN.This proof-of-concept study showed that, thanks to its higher elution strength, DMC can be considered a green alternative to ACN, since it allows to reduce method duration while reaching good purities and recoveries. Indeed, at a target purity fixed to 98.5 %, DMC led to the best productivity with respect to all the other solvents tested, confirming its suitability as a sustainable alternative to ACN for the purification of complex biopharmaceutical products.

Enhancing Selectivity of Protein Biopharmaceuticals in Ion Exchange Chromatography through Addition of Organic Modifiers

Charge heterogeneity among therapeutic monoclonal antibodies (mAbs) is considered an important critical quality attribute and requires careful characterization to ensure safe and efficacious drug products. The charge heterogeneity among mAbs is the result of chemical and enzymatic post-translational modifications and leads to the formation of acidic and basic variants that can be characterized using cation exchange chromatography (CEX). Recently, the use of mass spectrometry-compatible salt-mediated pH gradients has gained increased attention to elute the proteins from the charged stationary phase material. However, with the increasing antibody product complexity, more and more selectivity is required. Therefore, in this study, we set out to improve the selectivity by using a solvent-enriched mobile phase composition for the analysis of a variety of mAbs and bispecific antibody products. It was found that the addition of the solvents to the mobile phase appeared to modify the hydrate shell surrounding the protein and alter the retention behavior of the studied proteins. Therefore, this work demonstrates that the use of solvent-enriched mobile phase composition could be an attractive additional method parameter during method development in CEX.

Wettability Engineering of Solar Methanol Synthesis.

Engineering the wettability of surfaces with hydrophobic organics has myriad applications in heterogeneous catalysis and the large-scale chemical industry; however, the mechanisms behind may surpass the proverbial hydrophobic kinetic benefits. Herein, the well-studied In2O3 methanol synthesis photocatalyst has been used as an archetype platform for a hydrophobic treatment to enhance its performance. With this strategy, the modified samples facilitated the tuning of a wide range of methanol production rates and selectivity, which were optimized at 1436 μmol gcat-1 h-1 and 61%, respectively. Based on in situ DRIFTS and temperature-programmed desorption-mass spectrometry, the surface-decorated alkylsilane coating on In2O3 not only kinetically enhanced the methanol synthesis by repelling the produced polar molecules but also donated surface active H to facilitate the subsequent hydrogenation reaction. Such a wettability design strategy seems to have universal applicability, judged by its success with other CO2 hydrogenation catalysts, including Fe2O3, CeO2, ZrO2, and Co3O4. Based on the discovered kinetic and mechanistic benefits, the enhanced hydrogenation ability enabled by hydrophobic alkyl groups unleashes the potential of the surface organic chemistry modification strategy for other important catalytic hydrogenation reactions.