Product Purity Research Articles

Hydrogen Purity: Influence of Production Methods, Purification Techniques, and Analytical Approaches

Hydrogen Purity: Influence of Production Methods, Purification Techniques, and Analytical Approaches

Sequential Centrifugal Partition Chromatography Separation under Reduced Product Purity Requirements: Selection of the Operating Parameters

Sequential Centrifugal Partition Chromatography Separation under Reduced Product Purity Requirements: Selection of the Operating Parameters

Application Progress of Immobilized Enzymes in the Catalytic Synthesis of 1,3-Dioleoyl-2-palmitoyltriglyceride Structured Lipids

In recent years, the preparation of OPO (1,3-dioleoyl-2-palmitoyltriglyceride)-structured lipids through immobilized lipase catalysis has emerged as a research hotspot in the fields of food and biomedical sciences. OPO structured lipids, renowned for their unique molecular structure and biological functions, find wide applications in infant formula milk powder, functional foods, and nutritional supplements. Lipase-catalyzed reactions, known for their efficiency, high selectivity, and mild conditions, are ideal for the synthesis of OPO structured lipids. Immobilized lipases not only address the issues of poor stability and difficult recovery of free enzymes but also enhance catalytic efficiency and reaction controllability. This review summarizes the latest advancements in the synthesis of OPO structured lipids using immobilized lipases, focusing on immobilization methods, enhancements in enzyme activity and stability, the optimization of reaction conditions, and improvements in product purity and yield. Furthermore, it delves into the reaction mechanisms of enzymatic synthesis of OPO structured lipids, process optimization strategies, and the challenges and broad prospects faced during industrial applications.

An Alternative Method for the Selective Synthesis of Ortho-nitro Anilines Using Bismuth Nitrate Pentahydrate.

Nitroaromatic compounds are important scaffolds used for the syn-thesis of a variety of compounds, such as explosives, herbicides, dyes, perfumes and phar-maceuticals. Bismuth nitrate pentahydrate is a widely used reagent in organic synthesis; how-ever, its utility as a nitrating agent for anilines is underexplored. The aim of this work is to propose and find the proper reaction conditions of an alternative nitrating agent constituted by a mixture of bismuth nitrate / acetic anhydride in DCM with a series of substituted anilines under mild reflux. Several anilines having both activating and deactivating substituents in the ortho, meta and para positions were the substrate for the nitration reaction. Experimental conditions were performed in "one-pot" conditions before product purification. Bi(NO3)3•5H2O demonstrated to be effective and somehow regioselective when it came to the nitration of anilines in the ortho position. Although other products were also identified under these conditions, in most cases, the ortho derivative was the major or even the only product obtained with moderate to high yields in the range of 50% - 96%. Bi(NO3)3•5H2O is an efficient and safe nitrating agent since the use of concen-trated and corrosive acids like sulfuric and nitric is avoided; furthermore, bismuth nitrate is low-priced and no special care nor equipment is required.

Modeling and simulation of continuous fixed adsorptive distillation with adsorbent regeneration using thermal desorption

Modeling and simulation of continuous fixed adsorptive distillation with adsorbent regeneration using thermal desorption

Oxygen distribution in bed and safety analysis during hydrogen purification process from oxygen-containing feed gas

Oxygen distribution in bed and safety analysis during hydrogen purification process from oxygen-containing feed gas

A Review on “Chromatography: A Versatile Tool in Pharmaceutical Analysis and Allied Industries"

In pharmaceutical analysis, chromatography is a crucial analytical method that is extensively utilized to separate, determine, and measure the components of complicated mixtures. An outline of the basic ideas, historical evolution, and diverse uses of chromatography in the pharmaceutical and related sectors is given in this review. Chromatography, which began with Tswett's groundbreaking discovery in 1906, has developed into a flexible technique that uses both stationary and mobile phases for separation. The mechanics, guiding principles, and unique uses of techniques such as Gas Chromatography (GC), Liquid Chromatography (LC), (TLC), (HPLC), and High-Performance Thin Layer Chromatography (HPTLC) are thoroughly examined. The review explores the importance of immiscible phases in accomplishing selective molecule separation as well as partition and adsorption as the main separation methods. Applications cover a extensive range of domains, including as food safety, forensic science, environmental monitoring, quality control, and drug development. Chromatographic techniques have become essential for evaluating the purity of pharmaceutical products, guaranteeing their safety, and complying with regulatory requirements thanks to the integration of technological breakthroughs. The diversity of chromatography and its vital function in analytical research and industry are highlighted by this thorough study.

Improving the Long-term Enantioselectivity of a Silicon-Carbon Bond-Forming Enzyme.

Enantioselectivity is a key advantage of enzymatic catalysis. Understanding the most important factors influencing enantioselectivity necessitates thorough investigation for each specific enzyme. In this study, we explore various approaches to optimize reaction conditions for organosilicon production using an immobilized Cytochrome C recently tailored via directed evolution. Over extended reactions, this enzyme experiences a loss of enantioselectivity. Mass spectrometry (MS) revealed covalent modifications on the enzyme, but mutating the respective amino acids did not restore enantioselectivity. Nuclear magnetic resonance (NMR), along with a detailed comparison of the influence of reaction components such as cosolvents and reducing agents, indicated significant conformational changes in the presence of the diazo ester substrate. Additionally, we identified sodium ascorbate as a suitable and milder reducing agent compared to the previously used sodium dithionite, ensuring anaerobic conditions for silicon-carbon bond formation. Ultimately, maintaining a high enzyme-to-substrate ratio in the reaction was found to be crucial for achieving high enantiomeric purity of the organosilicon product over four days in sequential, repetitive batch reactions, thus improving the previously established reaction system. The methods and findings presented here are particularly valuable for addressing enantioselectivity issues in other enzymes that operate with diazo compounds as the substrates in carbene-transfer reactions.

An exploration of digital servitization business models in manufacturing SMEs

ABSTRACT Digital servitization, the integration of digital technologies into service-based business models, has gained significant traction in the industrial manufacturing sector. However, there is limited understanding of the conditions under which small and medium-sized enterprises (SMEs) develop specific digital servitization business models, owing partly to the lack of an appropriate business model typology. In this study, we develop a generalizable and operationalizable classification of digital servitization business models and identify the environmental and organizational factors that drive such business model innovation. We apply a multinomial logistic regression framework to analyze a dataset of 326 responses from UK manufacturing SMEs, providing insight into how the seven studied factors differentiate among SMEs following different digital servitization business models and more traditional ones (pure product or “just” servitized). The study contributes to the scarce empirical research on digital servitization in SMEs and provides implications for policy and practice.

Achieving Near Infrared Photodegradation by the Synergistic Effect of Z-Scheme Heterojunction and Antenna of Rare Earth Single Atoms.

Near-infrared light response catalysts have received great attention in renewable solar energy conversion, energy production, and environmental purification. Here, near-infrared photodegradation is successfully achieved in rare earth single atom anchored NaYF4@g-C3N4 heterojunctions by the synergistic effect of Z-scheme heterojunction and antenna of rare earth single atoms. The UV-vis light emitted by Tm3+ can not only be directly absorbed by g-C3N4 to generate electron-hole pairs, realizing efficient energy transfer, but also be absorbed by NaYF4 substrate, and generating photo-generated electrons at its impurity level, transferring the active charge to the valence band of g-C3N4, forming a Z-scheme heterojunction and further improving the photocatalytic efficiency. Importantly, Tm single atoms has multiple functions such as acting as charge transfer channels to facilitate charge transfer, regulating the critical distance of energy transfer, and prolonging electron-hole pair lifetime. Under NIR light, it exhibited remarkable performance in degrading antibiotics (the removal rate of TC reached 91% for 6 h) while maintaining excellent stability. The LC-MS/MS technology is used to reveal the reaction intermediates, active species, and reaction pathways, and the complex mechanism of photodegradation is further proposed. This study provides experimental and theoretical support for designing and synthesizing catalysts with near-infrared light response characteristics.

Advances in the catalytic promiscuity of nitrilases

As important biocatalysts, nitrilases can efficiently convert nitrile groups into acids and ammonia in a mild and eco-friendly manner, being widely used in the synthesis of important pharmaceutical intermediates. Early studies reported that nitrilases only had the hydrolysis activity of catalyzing the formation of corresponding carboxylic acid products from nitriles, showing catalytic specificity. However, recent studies have shown that some nitrilases exhibit the hydration activity for catalyzing the formation of amides from nitriles, showing catalytic promiscuity. The catalytic promiscuity of nitrilases has dual effects. On the one hand, the presence of amide by-products increases the difficulties and costs of subsequent separation and purification of carboxylic acid products. On the other hand, however, if the catalytic reaction pathways of nitrilases can be precisely regulated to reshape enzyme functions, the reactions catalyzed by nitrilases can be broadened to provide new ideas for the biosynthesis of high-value amides, which is crucial for the development of artificial enzymes and biocatalysis. This review summarized the research progress in the catalytic promiscuity of nitrilases and discussed the key regulatory factors that may affect the catalytic promiscuity of nitrilases from the evolutionary origin, catalytic domains, and catalytic mechanisms, hoping to provide reference and inspiration for the application of nitrilases in biocatalysis.

The reaction of thionyl chloride with β amino alcohols: A computational investigation to delineate the mechanisms of the well-established synthesis that forms the 1-chloro-(2-alkylamino)ethanes and the 1,2,3 alkyloxathiazolidine-2-oxide compounds

The substitution reaction mechanism of β-amino alcohols and thionyl chloride to form the 1-chloro-(2-alkylamino)ethane and the 1,2,3-alkyloxathiazolidine-2-oxide products was investigated using computational methods. The reactions that result in these compounds are very similar, they both use the N-(2-alkyl/arylamino)ethanols and thionyl chloride, however the synthesis of 1,2,3-alkyl/aryloxathiazolidine-2-oxide requires the use of an amine base, which quite commonly results in a purer product, not a different compound as is the case here. The mechanism of the formation of 1-chloro-(2-alkylamino)ethanes, involves the formation of a quaternary nitrogen species as one of the first steps. This step has a low relative energy barrier and occurs readily. It occurred in the reaction of all substituents tested except for the methyl and phenyl substituents. Based on this work it was demonstrated that the amine base is not actually needed to form the 1,2,3-alkyl/aryloxathiazolidine-2-oxide. Experimental reactions to produce the 1-chloro-(2-alkylamino)ethanes were performed and the products were characterized by 1H and 13C-NMR and GC-MS. The GC-MS experimental results supported the computational results, in that trace amounts of the 1,2,3-oxathiazolidine-2-oxides were found in the residue of this reaction. This demonstrated that the 1,2,3-oxathiazolidine -2-oxides can be formed in trace amounts without a base. The base would be required to make the 1,2,3-alkyloxathiazolidine-2-oxides in higher yields. The computational chemistry results demonstrate that the amine base suppresses the quaternization of the nitrogen by reacting preferentially with the acidic protons, which is the normal mode of action of the amine base in thionyl chloride reactions.

Dehydration-enhanced Ion Recognition of Triazine Covalent Organic Frameworks for High-resolution Li+/Mg2+ Separation.

The precise and rapid extraction of lithium from salt-lake brines is critical to meeting the global demand for lithium resources. However, it remains a major challenge to design ion-transport membranes with accurate recognition and fast transport path for the target ion. Here, we report a triazine covalent organic framework (COF) membrane with high resolution for Li+ and Mg2+ that enables fast Li+ transport while almost completely inhibiting Mg2+ permeation. The remarkably high rejection of Mg2+ by the COF membrane is achieved via imposed ion dehydration and the construction of the energy well. The proper hydrophilic environment of the COF channel promotes the dissociation of Li+ from the negatively charged functional groups, allowing Li+ for hopping transport supported by the sulfonate side-chains to shorten the diffusion path of Li+. Under high-salinity electrodialysis conditions, the COF membrane demonstrates robust Li+/Mg2+ separation performance (No Mg2+ were detected in the collected solution), achieving efficient lithium recovery and high product purity (Li2CO3: 99.3 %). This membrane design strategy enables high energy efficiency and powerful lithium extraction in the electrodialysis lithium extraction process, and can be generalized to other energy and separation related membranes.

Lemon Juice as a Natural Biodegradable Catalyst for an Ecofriendly One-Pot Pseudo-Three-Component Synthesis of N,1-Dimethyl-6-(methylsulfanyl)-3,5-dinitro-1,4-dihydropyridine-2-amines

AbstractA one-pot pseudo-three-component reaction strategy has been designed for synthesizing all-carbon-functionalized hexasubstituted N,1-dimethyl-6-(methylsulfanyl)-3,5-dinitro-1,4-dihydropyridine-2-amines under neat conditions using inexpensive, readily available, natural, biodegradable lemon juice as a catalyst. The acidic reaction environment induced by lemon juice provided a superior catalytic performance, with a high reaction rate and high product yields, to those of a pool of Lewis and Brønsted acid catalysts. The wide substrate scope and functional-group tolerance permitted diversity creation with electronic and structural variations in a robust and operationally simple manner. The recoverability/reusability of the lemon juice catalyst and the easy purification of the end products by precipitation/filtration avoid the need for column chromatography or hazardous organic solvents and confirm that this is an environmentally benign sustainable technology. Moreover, a gram-scale operation and chemical modifications of the final products demonstrated some promising advantages.

Electrochemical Cycling of Liquid Organic Hydrogen Carriers as a Sustainable Approach for Hydrogen Storage and Transportation.

Hydrogen (H2), as a high-energy-density molecule, offers a clean solution to carry energy. However, the high diffusivity and low volumetric density of H2 pose a challenge for long-term storage and transportation. Liquid organic hydrogen carriers (LOHCs) have been suggested as a strategic way to store and transport hydrogen in stable molecules. More so, electrochemical LOHC cycling renders an opportunity to utilize renewable energy for hydrogen storage and transportation toward the goal of eliminating carbon emissions. In this Perspective, examples of electrochemical reactions of organic molecules and their suitability for LOHC couples are examined. A comparative carbon footprint assessment of electrochemical LOHC cycling processes against thermochemical and hybrid LOHC cycling processes was performed. The electrochemical LOHC cycling process had the lowest relative carbon footprint only when highly concentrated LOHCs were used as the feed or when purification of the LOHC product was not required. The carbon footprint in electrochemical cycling of diluted LOHC was primarily contributed to by the LOHC distillation separation process. A sensitivity analysis showed the carbon footprint LOHC concentration dependence during the electrochemical cycling process. Moreover, the electrolyte composition significantly affects the carbon footprint during electrochemical LOHC cycling. Energy utilization, water usage, and toxicity for electrochemical LOHC cycling are discussed to provide an overview for better economic and environmental practices. There are significant opportunities in the electrochemical cycling of LOHCs if appropriate conditions such as high concentrations of reactant, reversible redox cycling ability, high Faradaic efficiencies, and catalyst stabilities are achieved.

Direct TiH2 powder production by the reduction of TiO2 using Mg in Ar and H2 mixed gas atmosphere

To develop a direct production process for TiH2 powder from TiO2, the reduction of TiO2 using Mg in molten MgCl2 – KCl salt under a high hydrogen chemical potential was investigated. The reduction of nano-sized TiO2 powder was conducted at 973 – 1073 K under an Ar or Ar and 10% H2 mixed gas atmosphere when the mass ratios of Mg to feed and salt to feed were 1.14 – 2.86 and 0.87 – 3.48, respectively. The results showed that the oxygen concentration in the Ti product decreased as the mass ratio of salt to feed and temperature decreased. Furthermore, according to the variation in Mg amounts, the oxygen concentration was 0.350 – 0.441 mass%. In addition, employing hydrogen during the reduction enhances the capability to decrease the oxygen concentration in the Ti product. Moreover, the hydrogen concentration in the Ti product increased as the amount of molten salt decreased, thereby enabling pure TiH2 production. As a result, TiH2 powder with an oxygen concentration of 0.350 mass% was obtained under a certain condition. These results demonstrate the feasibility of the direct production of low-oxygen TiH2 powder from TiO2 via reduction at 973 K using Mg in an Ar and H2 mixed gas atmosphere.

Empowering Community Entrepreneurship Through Salt-Based Mouthwash Production

In this PKM program, our partner is residents in Sedayulawas, Lamongan, East Java, Province. This community has generated the production mouthwash derived from salt. Salt is a mineral composed primarily of sodium chloride (NaCl). Diversification of salt products with various derivative products is very possible for salt farmers to do as an effort to empower the economy of the Lamongan community as well as increase food security through the provision of quality salt and downstream technology to produce salt derivatives that have more value for example mouthwash. Mouthwash containing saltwater rinses work by increasing the pH- balance inside the mouth, creating a much more alkaline oral environment in which the bacteria are no longer able to thrive. Based on interviews and observations in the field, there are 3 main focuses of the problems currently faced by partners, namely: 1) lack of knowledge about downstreaming of salt products and their derivatives and 2) the packaging of product. Efforts to increase salt production and salt purification technology as well as alternative diversification of salt derivative products can be a model that can drive the economic sector of the community of salt farmers and women who boil salt so as to initiate the opening of new job opportunities and create superior salt products and derivative products, namely mouthwash in Lamongan Regency. This activity was realized with an approach in the form of making a sustainable cooperation program until the end of PKM, creating a family atmosphere between the two and understanding that the problems experienced were a shared problem so that they could be solved together according to the level of responsibility to achieve the expected benefits, namely increased yields, production and productivity and competitiveness, independence and welfare of the community.

The influence of feed molar flow rate on key streams properties and duties in ethanol-water azeotropic distillation process

Investigation on the influence of near azeotropic feed molar flow rate on properties of key streams connecting main process units of an ethanol-water azeotropic distillation pilot processis presented. The heterogeneous azeotropic distillation model with cyclohexane entrainer was configured in Aspen Plus® V10 commercial simulation software. Property analysis and prediction of plant’s performancewere achieved using Non-Random Two Liquid Redlich-Kwong thermodynamic model. Both residual curve maps and ternary diagrams were used to determineseparation possibility and presence of ethanol-water azeotrope in the formed ternary mixtureduring distillation synthesis. The process convergence was addressed using flowsheet convergence and balance node. Distillation of ethanol- water azeotropic mixture was simulated at constant recycle ratio (R = 5), numberof stages (N = 12) and pressure (P = 1 atm). Data obtained were analysed in MS Excel 2013. Results showed that simultaneous increase ofmolar flow rate of the near azeotropic feed and feed ethanol concentration improves ethanol purity but results in retrograde phenomenon which may humper plant’s performance and increase stream flow rates and therefore increase energy duties. The condenser duty of the main column wasaround 90.94% higher than the recycle column’scondenser duty. Also, reboiler duty of the main column were nearly 90.25% higher than the recycle column’s reboiler duty.It was concluded that setting 18 to 20 kmol/h feed molar flow rate enhances higher energy efficiency and improves ethanol product purity. Careful distillation synthesis and plant’s monitoring are recommended to improve ethanol-water azeotropic distillation plant’s performance and address retrograde phenomena.

Bioprocess development for microbial production and purification of cellobiose lipids by the smut fungus Ustilago maydis DSM 4500.

Cellobiose lipids (CBLs) are a class of glycolipid biosurfactants produced by various fungal strains. These compounds have gained significant interest due to their surface-active and antifungal properties, which are comparable to traditional synthetic surfactants and antimicrobials. Despite their potential applicability in various cosmetic, pharmaceutical, and agricultural formulations, significantly less research has been focused on their production and purification in comparison to other glycolipid biosurfactants, such as mannosylerythritol lipids (MELs) and sophorolipids. Hence, this work proposes the development of a bioprocess that involves the microbial production and high-level chromatographic purification of CBLs from a submerged culture of Ustilago maydis DSM 4500. After a highly purified CBL product was obtained, the factors affecting the production of this glycolipid were investigated. It was demonstrated that U. maydis DSM 4500 produces a specific structural variant of CBLs at a concentration of 1.36g/L on an optimized the growth medium. Also, it was established that when the C/N ratio was decreased, the CBL titer increased by 2.3-fold. Furthermore, supplementing the culture with ZnSO4 at a concentration of 0.04mg/L further increased CBL concentration to 4.95g/L, representing the highest CBL titer achieved in a single-stage bioprocess to date. This study developed a methodology for utilizing U. maydis as a high-level CBL producer, which could challenge other familiar CBL producers, such as Sporisorium scitamineum and Cryptococcus humicola.

Immobilization of glycosyltransferase into a hydrophilic metal-organic framework for efficient biosynthesis of chondroitin sulfate.

Chondroitin sulfate (CS) is a structurally complex anionic polysaccharide widely used in medical, cosmetic and food applications. Enzymatic catalysis is an important strategy for synthesizing CS with uniform chain lengths and well-defined structures. However, the industrial application of glycosyltransferases is hindered by limitations such as low expression yields, poor stability, and challenges in reuse. We developed a mild and rapid one-step synthetic method for the efficient immobilization of chondroitin synthase (KfoC). The resulting KfoC@ZIF-90 composite exhibits high catalytic activity, thermal stability, and pH adaptability. Notably, KfoC@ZIF-90 exhibited 5-fold enhanced thermal stability at 40°C and retained 86 % relative activity at pH 10, while also maintaining 90 % activity in organic solvents, surpassing the performance of free KfoC. Molecular docking analysis revealed that the binding capability of encapsulated KfoC with substrate was stronger than that offree KfoC, thereby improving catalytic performance. Furthermore, KfoC@ZIF-90 can be easily separated from the reaction solution by centrifugation, simplifying product isolation and purification while enabling enzyme reuse. These attributes significantly enhance operability and reduce processing costs, making enzymatic CS synthesis more feasible for industrial applications.