Product Purity Research Articles

Boosting electrocatalytic alcohol oxidation: Efficient d–π interaction with modified TEMPO and bioinspired structure

AbstractAminoxyl radicals electrocatalysis presents a sustainable method for oxidizing alcohols into high‐value products. Nonetheless, the requirement for high doses of aminoxyl radicals diminishes product purity and economic viability. This study synthesized methylimidazole‐functionalized 4‐acetylamino‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl derivative (MIAcNH‐TEMPO) with a strongly electron‐withdrawing imidazole group and combined it with bioinspired nickel‐supported carbonaceous octopus tentacles for effective electrooxidation of alcohols, achieving high current density of 200 mA cm−2, selectivity of 99%, and turnover frequency of 26,490 h−1. In situ experiments and theoretical calculations indicated that the synergistic effect of Ni‐3dxz orbitals on the tentacle surface interacting with the π orbitals of MIAcNH‐TEMPO creates a strong d–π interaction, which effectively facilitating the creation of a locally intermediate‐enriched microenvironment, decreased the required quantity of aminoxyl radicals. Moreover, the high aqueous solubility of MIAcNH‐TEMPO reduces the difficulty of separation process. Scale‐up experiments conducted in a continuous flow electrolyzer showcased the potential of this strategy for practical applications.

Zero-inventory plans, constant workforce, or hybrid approach? Analysing pure production strategies for enhancing factory resilience with demand variability

Historically the notion of resilience capability has primarily been conceptualised as a holistic construct in the domain of supply chain networks – referred to as SCRES. The field of SCRES has since evolved gaining prominence among scholars and practitioners. However, the existing SCRES literature inadequately delves into the embedded resilience harboured by their constituent components, practices, or internal routines, including the aggregate production planning (APP) process. Therefore, the purpose of this article is to examine the interplay between medium-term pure strategies for APP and the resilience of manufacturing facilities, assuming demand to be the sole source of uncertainty. To accomplish this, a realistic Monte-Carlo simulation model integrated with a robust heuristic procedure for pure strategies is merged with a factory resilience index-based Cobb–Douglas function. The results of this research suggest that manufacturing facilities achieve a higher level of resilience when certain ‘zero-inventory plans’ are implemented. Based on this key finding, production/demand planners might incorporate the resilience dimension alongside the customary manufacturing success factors. Thus, to the best of the authors’ knowledge, this study represents the first attempt to establish a clear linkage between the implementation of pure APP strategies and a quantitative measure of factory resilience.

(3+3)‐Annulation of 2‐Mercaptobenzimidazoles With α‐(Trifluoromethyl)styrene Under Ultrasonic Irradiation

A rapid and facile sonochemical route for the [3+3] annulation of 2‐mercapto benzimidazoles with α‐(trifluoromethyl)styrene was reported for the synthesis of fluorinated benzo[4,5]imidazo[2,1‑b][1,3]thiazines. The reaction proceeds through the SN2/SNV pathway while the selective SN2 pathway is completely inhibited. The developed method is effective with a wide range of substrates, tolerating diverse functional groups. The pure products are obtained with high yield (up to 92%) directly via recrystallization without column chromatography. Furthermore, applying sonochemical methodology reduces the reaction time and eliminates the need for expensive photocatalysts, ligands or oxidants.

Characterization of the exopolysaccharides produced by the industrial yeast Komagataella phaffii.

The yeast Komagataella phaffii has become a popular host strain among biotechnology startup companies for producing recombinant proteins for food and adult nutrition applications. K. phaffii is a host of choice due to its long history of safe use, open access to protocols and strains, a secretome free of host proteins and proteases, and contract manufacturing organizations with deep knowledge in bioprocess scale-up. However, a recent publication highlighted the abundance of an unknown polysaccharide that accumulates in the supernatant during fermentation. This poses a significant challenge in using K. phaffii as a production host. This polysaccharide leads to difficulties in achieving high purity products and requires specialized and costly downstream processing steps for removal. In this study, we describe the use of the common K. phaffii host strain YB-4290 for production of the bioactive milk protein lactoferrin. Upon purification of lactoferrin using membrane-based separation methods, significant amounts of carbohydrate were co-purified with the protein. It was determined that the carbohydrate is mostly composed of mannose residues with minor amounts of glucose and glucosamine. The polysaccharide fraction has an average molecular weight of 50 kDa and consists mainly of mannan, galactomannan and amylose. In addition, a large fraction of the carbohydrate has an unknown structure likely composed of oligosaccharides. Additional strains were tested in fermentation to further understand the source of the carbohydrates. The commonly used industrial hosts, BG10 and YB-4290, produce a basal level of exopolysaccharide; YB-4290 producing slightly more than BG10. Overexpression of recombinant protein stimulates exopolysaccharide production well above levels produced by the host strains alone. Overall, this study aims to provide a foundation for developing methods to improve the economics of recombinant protein production using K. phaffii as a production host.

Green Analytical Method Development and Validation Studies of Viloxazine Hydrochloride in Pure and Commercial Products Using UV-Vis Spectroscopy

Green Analytical Method Development and Validation Studies of Viloxazine Hydrochloride in Pure and Commercial Products Using UV-Vis Spectroscopy

Experimental Study on Preparation of Nano ZnO by Hydrodynamic Cavitation-Enhanced Carbonization Method and Response Surface Optimization

The carbonization method for preparing Nano ZnO is characterized by its simplicity, ease of reaction control, high product purity, environmental friendliness, and potential for CO2 recycling. However, traditional carbonization processes suffer from poor heat and mass transfer, leading to in situ growth and agglomeration, resulting in low carbonization efficiency, small specific surface area, and inferior product performance. To enhance micro-mixing and mass transfer efficiency, ZnO derived from zinc ash calcination was used as the raw material, and hydrodynamic cavitation technology was employed to intensify the carbonization reaction process. The reaction mechanism of hydrodynamic cavitation was analyzed, and a single-factor experimental study investigated the effects of reaction time, reaction temperature, solid–liquid ratio, calcination temperature, incident angle, cavitation number, and position height on the specific surface area and carbonization rate of Nano ZnO. The response surface method was utilized to explore the significance of the three most influential factors—solid–liquid ratio, cavitation number, and position height—on the carbonization rate and specific surface area. The products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analysis, and specific surface area analysis. The results showed that the optimal process parameters were a reaction temperature of 80 °C, a reaction time of 120 min, a solid–liquid ratio of 5.011:100, a calcination temperature of 500 °C for 1 h, an incident angle of 60°, a cavitation number of 0.366, and a position height of 301.128 mm. The interaction between solid–liquid ratio and position height significantly influenced the process parameter variations. Under these conditions, the specific surface area and carbonization rate were 63.190 m2/g and 94.623%, respectively. The carbonized product was flaky Nano ZnO with good dispersion and small particle size. Compared to traditional mechanical stirring and bubbling methods, the specific surface area increased by 1.5 times, the carbonization rate improved by 10%, and the particle size decreased by half, significantly enhancing the product performance.

Fe3O4@SiO2@[Aminoglycol][Formate] as a new superparamagnetic nanocatalyst and [Aminoglycol][Formate] as a novel ionic liquid catalyst for preparation of new dimethyldihydropyrimido[4,5-b]quinolone derivatives.

Efficient synthesis of novel dimethyldihydropyrimido[4,5-b]quinolones via three-component condensation of barbituric acid, arylaldehydes, and 3,4-dimethylaniline catalyzed by Fe3O4@SiO2@[Aminoglycol][Formate] as a new superparamagnetic nanocatalyst and [Aminoglycol][Formate] as a novel ionic liquid catalyst was described. The new heterogeneous nanocatalyst was characterized by FE-SEM, XRD, FT-IR, TGA-DTG, and VSM techniques. The new ionic liquid was characterized by 13CNMR, 1HNMR, and FT-IR techniques. The present work has advantages, such as excellent yields, short reaction times, environmentally friendly protocol, easy separation, and purification of products. The catalysts kept its catalytic properties after even five recoverability and reusability.

Evaluation of sea surface temperature from ocean reanalysis products over the North Indian Ocean

Ocean and sea ice reanalyses (ORAs or ocean syntheses) are reconstructions of the ocean and sea ice states using an ocean model integration constrained by atmospheric surface forcing and ocean observations via a data assimilation method. Ocean reanalyses are a valuable tool for monitoring and understanding long-term ocean variability at depth, mainly because this part of the ocean is still largely unobserved. Sea surface temperature (SST) is the key variable that drives the air–sea interaction process on different time scales. Despite improvements in model and reanalysis schemes, ocean reanalyses show errors when evaluated with independent observations. The independent evaluation studies of SST from ocean reanalysis over the Indian Ocean are limited. In this study, we evaluated the SST from 10 reanalysis products (ECCO, BRAN, SODA, NCEP-GODAS, GODAS-MOM4p1, ORAS5, CGLORS, GLORYS2V4, GLOSEA, and GREP) and five synthetic observation products (COBE, ERSST, OISST, OSTIA, and HadISST) and from the pure observation-based product AMSR2 for 2012–2017 with 12 in-situ buoy observations (OMNI) over the Arabian Sea and Bay of Bengal. Even though the reanalysis and observational products perform very well in the open ocean, the performance is poorer near the coast and islands. The reanalysis products perform comparatively better than most of the observational products. COBE and OISST perform better among the synthetic observational products in the northern Indian Ocean. GODAS-MOM4p1 and GREP performs best among the reanalysis products, often surpassing the observational products. ECCO shows poorer performance and higher bias in the Bay of Bengal. Comparing the BRAN daily and monthly SST, the monthly SST performance of reanalysis is better than the daily time scale.

A novel pillar-layered MOF with urea linkers as a capable catalyst for synthesis of new 1,8-naphthyridines via the anomeric-based oxidation

Metal-based catalysts play an essential role in organic chemistry and the chemical industry. This research designed and successfully synthesized a pillar-layered metal–organic framework (MOF) with the urea linkers, namely Basu-HDI, as a novel and efficient heterogeneous catalyst. Various techniques such as FT-IR, EDX, elemental mapping, SEM, XRD, BET, and TGA/DTA studied its structure and morphology. Then, we investigated the synthesis of new 1,8-naphthyridines utilizing Basu-HDI in mild conditions via a one‐pot, three‐component tandem Knoevenagel/Michael/ cyclization/anomeric-based oxidation reaction. Final products were achieved by anomeric-based oxidation without employing an oxidation agent. Remarkably, this tandem process gave a good range of new 1,8-naphthyridines with high yields in a short reaction time. The pure products were confirmed by FT-IR, 1H NMR, 13C NMR, and mass spectrometry techniques. Moreover, the introduced catalyst showed good efficiency and stability and can be reused four times without significantly reducing efficiency.

Rational Design of Enhanced Nme2Cas9 and Nme2SmuCas9 Nucleases and Base Editors.

CRISPR-Cas genome editing tools enable precise, RNA-guided modification of genomes within living cells. The most clinically advanced genome editors are Cas9 nucleases, but many nuclease technologies provide only limited control over genome editing outcomes. Adenine base editors (ABEs) and cytosine base editors (CBEs) enable precise and efficient nucleotide conversions of A:T-to-G:C and C:G-to-T:A base pairs, respectively. Therapeutic use of base editors (BEs) provides an avenue to correct approximately 30% of human pathogenic variants. Nonetheless, factors such as protospacer adjacent motif (PAM) availability, accuracy, product purity, and delivery limit the full therapeutic potential of BEs. We previously developed Nme2Cas9 and its BE derivatives, including ABEs compatible with single adeno-associated virus (AAV) vector delivery, in part to enable editing near N4CC PAMs. Further engineering yielded domain-inlaid BEs with enhanced activity, as well as Nme2Cas9/SmuCas9 chimeras that target single-cytidine (N4C) PAMs. Here we further enhance Nme2Cas9 and Nme2SmuCas9 editing effectors for improved efficiency and vector compatibility through site-directed mutagenesis and deaminase linker optimization. Finally, we define the editing and specificity profiles of the resulting variants by using paired guide-target libraries.

Ionic Liquid-Based Green Solvents for Extraction and Purification of Natural Plant Products

Introduction: This research paper explores the environmental sustainability of ionic liquid-based green solvents in the extraction and purification of natural plant products, with a focus on their entire life cycle. The objectives of the study were to assess the environmental impact of ionic liquid synthesis, energy consumption, water usage, emissions, recycling rates, policy effects, and stakeholder perceptions. Methods: Methodologically, we conducted a comprehensive Life Cycle Assessment (LCA) that involved primary data collection through field surveys and interviews with key stakeholders in the ionic liquid production and usage industry across various regions in India. The data were analyzed using specialized LCA software tools to quantify environmental impacts. Key findings include the identification of synthesis as a major contributor to environmental impact, emphasizing the need for greener synthesis methods. Results: The study revealed the significant carbon footprint, energy consumption, and water usage during production, highlighting opportunities for improvement. Emissions data underscored the importance of emission control measures, particularly for greenhouse gases and volatile organic compounds. Recycling and reuse were identified as environmentally friendly disposal methods. Policy compliance varied among stakeholders, indicating room for stricter regulations. Stakeholder perceptions varied, with researchers having the most positive outlook. Implications of the findings extend to sustainable chemistry practices, emphasizing interdisciplinary collaboration and the importance of considering the entire life cycle of chemical processes. Conclusion: This research contributes to a deeper understanding of green solvents and provides a foundation for promoting sustainable practices in industrial processes in India and globally.

Electrochemical Drawdown of U3+ and Ce3+ in Molten LiCl-KCl Using a Liquid Cadmium Cathode

Abstract The electrorefining of spent nuclear fuels is a key step to recover uranium and transuranium on separated cathodes. However, the electrolyte salts become contaminated with fission products after batches of electrorefining, and therefore the two unit processes for the drawdown of actinide and lanthanide are suggested before treatment of the contaminated salts. We investigated the electrochemical drawdown of U3+, Ce3+, and U3+ from Ce3+ in molten LiCl-KCl electrolyte using a liquid cadmium cathode (LCC) at 773 K. The drawdown mechanism of U3+ and Ce3+ was determined by cyclic voltammograms and calculating the equilibrium potential. After galvanostatic electrolysis, high recovery yields were obtained for the drawdown of U3+ and Ce3+, but the current efficiency of Ce3+ was at least twice as high as that of U3+ due to the cyclic electrolysis of U3+/U4+. Despite significant underpotential deposition of Ce3+ in the LCC, an exceptional separation factor for Ce relative to U reached 84.67 ± 17.13, which was attributed to the formed pure uranium products hindering the subsequent deposition of Ce3+. Moreover, pure uranium products and Ce-Cd intermetallic compounds were characterized by X-ray diffraction and scanning electron microscope coupled with energy dispersive X-ray spectroscopy.

Controlling the Crystalline Quality and Yield of Single‐Walled Carbon Nanotubes via Floating Catalyst Chemical Vapor Deposition Synthesis

AbstractCarbon nanotubes (CNTs) were synthesized by floating catalyst chemical vapor deposition (FCCVD) reactions. The complicated processing parameters that included a precursor solution composition, reaction temperature, flow rate of the carrier gas, weak oxidants, and injection rate of the precursor solution were controlled to synthesize single‐walled carbon nanotubes (SWCNTs) during the reaction process. The effects of the processing parameters were analyzed with respect to the formation of SWCNTs, yield, and the crystallinity in the CNTs structure. The SWCNTs were characterized by the Raman spectroscopy, scanning electron microscope, high‐resolution transmission electron microscopy, and thermogravimetric analysis. A high reaction temperature, high H2 flow rate, low injection rate of solution precursor, and low concentrations of iron catalysts in the reaction were important factors to improve the crystalline quality of the SWCNTs. The purity of the initial product grown by the standard process was more than 90 wt %, with a yield of 0.5 g/h. The average G/D ratio of the initial product was 178, and it had a distinct RBM peak. HRTEM confirmed that the synthesized SWCNTs had high purity and crystallinity. The SWCNTs could be tunable to meet a particular application by varying the reaction conditions.

Investigation into the purification and regeneration of rare earth polishing powder waste via continuous solid-phase conversion

The concentration of rare earth elements (lanthanum, cerium, and praseodymium) within rare earth polishing powder waste (REPPW) typically exceeds 50 %, with the majority of impurities comprised of silicon and aluminum-related compounds. Transforming REPPW into recycled rare earth polishing powders that adhere to polishing standards in an eco-friendly and economically viable way presents a significant challenge in the industry. Traditional acid or alkaline processes predominantly recover rare earth elements as oxides, which are underutilized due to their high costs. Considering the varying forms of impurities and rare earth compounds found in REPPW, this research introduces a novel physicochemical decontamination and continuous chemical transformation process aimed at producing regenerated rare earth polishing powders. Under optimal conditions, the physicochemical two-step decontamination process achieved a rare earth recovery rate surpassing 92 %, while silicon and aluminum removal rates reached 86.12 %. During the continuous chemical transformation of REPPW, the rare earth phases in an alkaline setting followed the sequence REOF (CeO2) → RE(OH)3 → RECO3OH→RECO3F→CeLa2O3F3(CeO2), which not only facilitated phase reorganization but also enhanced the particle surface structure. Notably, these chemical transformations did not disrupt the rare earth distribution; instead, they indirectly boosted product purity and uniformly dispersed within the regenerated polishing powder particles, thereby improving polishing efficiency. Consequently, the adoption of this innovative regeneration process for polishing powders holds substantial importance for the sustainable utilization of rare earth resources.

Process swing adsorption with selective purge gas recirculation (PSA-SPUR): Adsorption process technology optimised for separation of heavy component from a gas mixture and its design for CO2 capture through Equilibrium Theory analysis

PSA-SPUR (Pressure Swing Adsorption with Selective Purge Gas Recirculation) has been developed aimed at separating the most strongly adsorbing component from a gas mixture at high product purity and recovery. The innovative strategy for designing a Pressure Swing Adsorption system features recycling its purge gas stream exiting the column and mixing it back into the feed. This operation enriches the mixed feed with an elevated fraction of the heavy component during the adsorption step, thus enhancing the PSA’s performance greatly. Reusing the purge gas helps significantly increase the product recovery compared to conventional methods where purge gas is simply discarded or taken as a low-quality product. For theoretical analysis of a PSA-SPUR system, a bespoke Equilibrium Theory model was developed and solved successfully, providing valuable insights into the performance of the PSA-SPUR system designed for capturing CO2 from a flue gas. The study revealed that there exists an optimum extent of purging that maximises the heavy component mole fraction in the mixed feed, leading to the best possible feed throughput of the adsorption system. Furthermore, the effects of the desorption pressure and feed composition on the PSA-SPUR system’s performance were investigated. The results indicate that the CO2 capture PSA-SPUR system using commercial zeolite 13X has excellent potential to achieve very high product purity and recovery, being allowed to operate at moderate vacuum pressures without having to compress the flue gas feed, even when the gas feed contains less than 10 mol% CO2.

β‐Cyclodextrin‐SO3H as a Supramolecular Catalyst for Efficient Greener Synthesis of Substituted Bis(6‐aminouracil‐5‐yl)methanes in Water

AbstractA simple, straightforward, and highly efficient greener approach for synthesizing bis(6‐aminouracil‐5‐yl)methane derivatives was developed by employing β‐cyclodextrin‐SO3H as supramolecular catalyst in water at 100 °C. A total of 16 bis(6‐aminouracil‐5‐yl)methanes were synthesized via a one‐pot reaction between substituted aromatic aldehydes, 6‐amino‐1,3‐dimethyluracil, and 10% β‐cyclodextrin‐SO3H in water with 84%–92% yield within 20–120 min. The salient features of this protocol included water as green solvent, β‐cyclodextrin‐SO3H as recyclable supramolecular catalyst, mild reaction conditions, easy isolation of pure products, and good to excellent yields.

Rapid solvent transport and tunable molecular sieving enabled by ultrathin alkyl-chain-engineered polyamide membranes

Organic solvent nanofiltration (OSN) has emerged as a promising separation technology for the chemical and pharmaceutical industries due to its low energy consumption and eco-friendliness. However, traditional polyamide-based membranes used in OSN often exhibit low permeance for organic solvents and it is difficult to precisely control the pore structure. In this study, we report a facile approach to fabricate ultrathin alkyl-chain-engineered polyamide nanofilms via free-standing interfacial polymerization for high-performance selective separations. The membranes were prepared via a “two birds one stone” strategy, enabled by post-treatment in aliphatic amine solution, simultaneously regulating the pore size and optimizing the membrane chemical property. This enables the membrane with high solvent permeance, especially for non-polar solvents (heptane at ∼22.2 L m−2h−1 bar−1, toluene at ∼16.8 L m−2h−1 bar−1), while maintaining excellent molecular sieving capability. Notably, the molecular weight cut-off (MWCO) can be regulated by introducing alkyl chains of varying lengths to their pores. The exceptional solvent permeance and tunable molecular sieving property make the membranes promising for high value-added products purification in the pharmaceutical industry and crude oil separation.

Расчетно-экспериментальное исследование и идентификация матричной модели струйного измельчения сыпучих материалов

Grinding powders in jet mills makes it possible to obtain materials uncontaminated by wear products of grinding media to prepare pure products in chemical and pharmaceutical industries. It should be noted that for different technologies, the requirements for the granulometric composition of powders vary significantly, and to meet these requirements, specific approaches are often required. Experimental determination of optimal conditions to obtain new powders is often associated with significant costs, which is not always justified from an economic point of view. Mathematical modeling allows us to obtain effective solutions in a shorter time and at lower costs in most cases. Thus, the development of adequate models, methods of calculation and optimization of jet grinding technology is an urgent scientific and practical task. To simulate grinding, a matrix methodology is used to describe technological processes. To identify the model, the results of specially conducted experimental studies are used. During experimental studies, the granulometric compositions of powders after single and multiple grinding in a jet mill have been determined. The results obtained have been used to identify and verify the matrix grinding model. Within the framework of the resulting model, a method for technological calculation of a jet mill operating in an open grinding cycle has been developed. The presented approach allows us to propose the ways to develop and implement new jet grinding technologies to obtain highly pure products in open and closed grinding cycles.

Green and Fast Synthesis of NiCo-MOF for Simultaneous Purification-Immobilization of Bienzyme to Catalyze the Synthesis of Ginsenoside Rh2.

Traditional metal-organic frameworks (MOFs) preparation is generally time-consuming, polluting, and lacking specificity for enzyme immobilization. This paper introduced a facile, rapid, and green method to produce three MOFs subsequently employed to purify and coimmobilize recombinant glycosyltransferase (UGT) and recombinant sucrose synthetase (SUSy) using histidine tag (His-tag) for the specific adsorption of Ni2+ and Co2+ from MOFs. This method simplified enzyme purification from crude extracts and enabled enzymes to be reused. The results demonstrated that NiCo-MOF exhibited a higher enzyme load (115.9 mg/g) than monometallic MOFs. Additionally, the NiCo-MOF@UGT&SUSy demonstrated excellent stability and efficiently produced the rare ginsenoside Rh2 by catalyzing a coupling reaction (95.6 μg/mL), solving the problem of the substrate cost of uridine diphosphate glucose (UDPG). The NiCo-MOF@UGT&SUSy retained 68.97% of the initial activity after 10 cycles. Finally, molecular docking studies elucidated the conversion mechanism of the target product Rh2. This technique is important in the industrialization of ginsenoside production and enzyme purification.

Supercritical mechano-exfoliation process

The intricate balance among cost, output, and quality has substantially hindered the practical application of graphene within the downstream industry chain. Here we present a scalable and green supercritical CO2-assisted mechano-exfoliation (SCME) process that omits the use of organic solvents and oxidants throughout the production lifecycle, including exfoliation, separation, and purification. The SCME process achieves graphene powder space-time yields exceeding 40 kg/(m³·day) at laboratory (0.06–0.2 kg) and pilot scales ( > 4 kg), with resultant free-standing films showing conductivities up to 5.26 × 10⁵ S/m. Further kinetic investigations propose general guidelines for grinding-assisted exfoliation: (1) the macroscopic optimizing ability of mechanotechnics for mass transfer frequency and stress distribution and (2) the microscopic multiplication ability of exfoliation medium for shear-delamination. The comprehensive techno-economic analysis also underscores the economic viability of the SCME process for large-scale production.