Enantiopure [2 + 3] covalent organic cages deriving from the 3,3’-diformyl-2,2’-BINOL building block are produced through a dynamic covalent chemistry approach. These architectures are formed with different triamino caps, 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene (2a), 1,3,5-tris(aminomethyl)-2,4,6-trimethylbenzene (2b), and 2,7,14-triaminotriptycene (3). For the synthesis of the cage 6b containing 3, a less direct synthetic route regarding the formation of the amine cages (4a and 4b) generated from the spacers 2a and 2b was followed. Instead of being directly synthesized from 3,3’-diformyl-2,2’-BINOL, the targeted compound 6b required a protected BINOL derivative. The ability of the three cages to host the 1-phenylethylammonium cation (8+) as a guest was evaluated through UV–vis titration, CD, and DOSY NMR studies. while the formation of the supramolecular complex 8+ with cage 6b was not possible, cages 4a and 4b were able to bind 8+ with the same enantiopreference, higher association constants being obtained for cage 4a. The association constants determined for the host–guest complexes are discussed in relation with the cavity size calculated for the host cages.

This work explores a selective continuous enzymatic reactive distillation (ERD) using innovative structured metallic packings functionalized with Candida antarctica lipase B (CALB)-loaded xerogels for the selective production of (R)-2-pentylbutyrate. Aluminum open-cell foams (10 and 20 ppi) and 3D-printed Tetra Splines were employed for the first time as packings in ERD systems, distinguishing from the usual wire gauze structures. The structure surfaces were pretreated with a GPTMS primer to significantly enhance the biocatalytic coating adhesion and stability. Continuous ERD experiments were conducted to evaluate the effects of catalyst load, packing type, feed composition, and reflux ratios, revealing minimal catalyst leaching and sustainable high catalytic activity. Reaction yields reached up to 80.8% with an excellent enantiomeric excess of 90%, successfully overcoming the thermodynamic equilibrium of the reaction. An equilibrium-stage model was developed, effectively representing the setup without its experimental flaws. Parametric analyses using this model identified key operational parameters critical for process optimization with a comprehensive understanding of their impact on the process performances. A pilot plant of the selective ERD process was then simulated based on this study. Further research is required to better understand how operating parameters affect the reduction of enzyme selectivity in ERDs and to identify strategies, potentially involving new or less conventional column designs such as ERDWC, to minimize these losses.

Monomethylgermanium (MMGe), the dominant organogermanium species in aquatic systems, exists predominantly as the neutral mononuclear species (CH3)Ge(OH)3 under environmentally relevant conditions. MMGe displays conservative behavior in freshwater and marine environments, an observation consistent with high chemical stability, yet its fundamental acid–base properties remain poorly characterized. To address this gap, we investigated the protolytic properties of (CH3)Ge(OH)3 at 298.2(2) K across a range of ionic strengths (0.1–1.0 mol·L−1) and five supporting electrolytes (LiCl, NaCl, KCl, CsCl, TMACl) by glass-electrode potentiometry. The first deprotonation constant (pKa = –log K1) of (CH3)Ge(OH)3 was consistently determined across experimental conditions with values ranging from 11.07(4) to 11.22(3), except in 1 mol·L−1 TMACl, where an anomalously high value (11.62(5)) was attributed to specific ion effects. 1H and 13C NMR titrations in 1 mol·L−1 KCl confirmed a single protonation equilibrium with pKa = 11.22(1), in excellent agreement with the potentiometric results. No evidence was found for the formation of a doubly deprotonated species under the investigated p[H] range (< 13). These findings contribute fundamental thermodynamic data for MMGe and enhance our understanding of its chemical behavior in natural waters.

Plutonium (Pu) is a chemically and radiologically toxic element, primarily of anthropogenic origin. Reagents that specifically sequester Pu have been developed in the frame of nuclear waste processing and storage. Other potential applications of Pu chelators are in vivo decorporation and environmental remediation. Although the medical application has been addressed for a long time by the development of Pu-specific binders, studies concerning the environmental application are scarce. A desferrioxamine-B ([(DFO)H4]+)-derived tetrahydroxamate chelator, 1H4, which was originally designed for the sequestration of Zr4+ for 89Zr-ImmunoPET applications, was grafted on a commercial hydrophilic resin, CM Sephadex C-25 (R). The resin beads were subsequently embedded in an agarose gel, and the resulting material was used for the extraction of 238Pu(iv) from dilute aqueous solutions at pH 6.5. Comparison of the results with those obtained using the commercial Chelex (R)-100 resin and the H3DFO-based CM Sephadex C-25 (R) extracting materials showed that Pu was more strongly bound to the 1H4-functionalized resin than to Chelex (R)-100 and the H3DFO-based resins, which confirms that the tetrahydroxamate chelator 14- forms a more stable Pu(iv) complex than the trihydroxamate DFO3- siderophore. The fabricated material could be considered in the development of diffusive gradients in thin-films (DGT) devices for the environmental monitoring of Pu.

Additive manufacturing has facilitated new design possibilities for gas-liquid contactors by enabling the creation of complex geometries to enhance performance. A novel design approach is introduced for column packing, based on triply periodic minimal surfaces (TPMS). This approach combines the unique properties of these surfaces with the advantageous features of wire-based structures. As an initial step, canonical TPMS were integrated to develop a new surface design. The equation representing this surface was subsequently adjusted to control packing dimensions, such as the strut diameter and other characteristics. Three prototypes based on TPMS, each with distinct dimensions, were evaluated through CFD simulation. A small-scale domain of the packing (DN25) was found to align with experimental results for gas-solid pressure drop. When comparing the prototypes, pressure drop exhibited a stronger dependency on strut diameter, higher for larger diameters. Additionally, the gas velocity profile within the packing section suggested that a larger strut diameter may lead to better gas-liquid contact.

Water-soluble porphyrins have garnered significant attention due to their broad range of applications in biomedicine, catalysis, and material chemistry. In this work, water-soluble platinum(ii) and palladium(ii) complexes with porphyrins bearing ethyl phosphonate substituents, namely, Pt/Pd 10-(ethoxyhydroxyphosphoryl)-5,15-di(p-carboxyphenyl)porphyrins (M3m, M = Pt(ii), Pd(ii)) and Pt/Pd 5,10-bis(ethoxyhydroxyphosphoryl)-10,20-diarylporphyrins (M1d-M3d; aryl = p-tolyl (1), mesityl (2), p-carboxyphenyl (3)), were synthesized by alkaline hydrolysis of the corresponding diethyl phosphonates M6m and M4d-M6d. NMR, UV-vis, and fluorescence spectroscopy revealed that the mono-phosphonates M3m tend to form aggregates in aqueous media, while the bis-phosphonates M3d exist predominantly as monomeric species across a wide range of concentrations (10-6-10-3 M), ionic strengths (0-0.81 M), and pH values (4-12). Single-crystal X-ray diffraction studies of the diethyl phosphonates Pt6d and Pd6d revealed that pi-pi stacking of the aromatic macrocycles is sterically hindered in the crystals, providing a rationale for the low degree of solution aggregation observed for ethyl phosphonate M3d. Photophysical studies of M3m and M1d-M3d demonstrated that these compounds are phosphorescent and generate singlet oxygen in aqueous solutions. Pd(ii) complex Pd3d is an excellent photocatalyst for the oxidation of sulfides using di-oxygen in a solvent mixture (MeCN/H2O, 4 : 1 v/v). Under these conditions, various alkyl and aryl sulfides were quantitatively converted into the desired sulfoxides. For the oxygenation of mixed alkyl-aryl sulfides, Pd3d outperforms Pd(ii) meso-tetrakis(p-carboxyphenyl)porphyrin (PdTCPP). This photocatalyst can be recycled and reused to afford sulfoxides with no loss of product yield.

The definition of reliable equilibrium constants is an essential step in speciation studies, as the uncertainty and the consistency of the estimated values concur to define the reliability of the speciation model. It is therefore necessary to evaluate the uncertainty contribution of all factors involved at each step of the data acquisition procedure and to be aware about the consequences of systematic errors on the best-estimated values of experimentally measured equilibrium constants. In this work, a series of computer-generated H+-ion selective electrode titration curves simulating the alkalimetric titration of equimolar mixtures of Zn2+-EDTA in aqueous solutions have been processed by different equilibrium data fitting software. Hence, the uncertainties of the refined stability constants of the Zn2+-EDTA complexes could be derived, while excluding the experimental variability that intrinsically affects all practical experiments. The sensitivity of a given chemical system to different data processing strategies and to possible errors in the input data was evaluated. The systematic errors considered relate to the potential reading, the concentration of the titrant and solution components, and ionic strength variations during titrations. The outcomes highlight how unsuitable decisions taken at the stage of nonlinear least squares fitting of the data can affect the results and underline that the main error contribution is related to the measurement of the glass-electrode potential. The processing of simulated data sets can be a useful tool to alert the researchers to the sensitivity of a given chemical system to different strategies and to possible errors in the input data.

Rotating packed beds (RPBs) enhances mass transfer processes because a centrifugal force which is several -times greater than gravity is used as the driving force. The complexity of fluid flow across RPBs has made predicting and accurately determining their hydrodynamic behaviours difficult. The flooding point as a hydrodynamic characteristic is essential for the accurate design and scale-up of RPBs. However, variations in flooding point definitions and methodologies across the literature highlight the need for standardized approaches in studying RPB flooding phenomena. This study compared four approaches based on pressure drop fluctuations and the volume of liquid ejected from the RPB to determine the onset of flooding in RPBs using experimental results from a pilot-scale counter-current RPB. For rotational speeds of 300 -1500 rpm, gas flow rate of 100-300 Nm3/h, and liquid flow rates of 0.39-0.75 m3/h, the pressure drop varied from 314 to 2,100 Pa. Quantitative comparisons of the results based on different flooding point definitions showed wide variations with the values of the pressure drop at the onset of flooding differing by as much as 325 %. A quantitative approach based on virtual observations and the ejection of 8 % of the total liquid flow rate from the rotor’s eye is proposed as the standard method for identifying the onset of flooding in RPBs.

Defining the distribution of the chemical species in a multicomponent system is a task of great importance with applications in many fields. To clarify the identity and the abundance of the species that can be formed by the interaction of the components of a solution, it is fundamental to know the formation constants of those species. The determination of equilibrium constants is mainly performed through the analysis of experimental data obtained by different instrumental techniques. Among them, potentiometry is the elective technique for this purpose. As such, a survey was run within the NECTAR COST Action - Network for Equilibria and Chemical Thermodynamics Advanced Research, to identify the most used software for the analysis of potentiometric data and to highlight their strengths and weaknesses. The features and the calculation processes of each software were analyzed and rationalized, and a simulated titration dataset of a hypothetic hexaprotic acid was processed by each software to compare and discuss the optimized protonation constants. Moreover, further data analysis was also carried out on the original dataset including some systematic errors from different sources, as some calibration parameters, the total analytical concentration of reagents and ionic strength variations during titrations, to evaluate their impact on the refined parameters. Results showed that differences on the protonation constants estimated by the tested software are not significant, while some of the considered systematic errors affect results. Overall, it emerged that software commonly used suffer from many limitations, highlighting the urgency of new dedicated and modern tools. In this context, some guidelines for data generation and treatment are also given.

Additive manufacturing has widened the possibilities of design for gas-liquid packing geometries in recent years, allowing for new unexplored shapes. A novel design approach based on triply periodic minimal surfaces (TPMS1), an interesting class of smoothened curved surfaces, led to the conception of new periodic structures with complex geometrical features. The present study aims to assess the applicability of these new TPMS-based geometries as packing for gas-liquid contactors and the effect of their topology on performance. Liquid holdup, pressure drop, flooding and mass transfer efficiency were evaluated for three TPMS-based prototypes, with distinct characteristic dimensions. A new experimental setup was developed for the estimation of liquid holdup based on the measure of the liquid weight during operation by a set of load cells. Results show good repeatability and precision, allowing to distinguish liquid holdup between the prototypes for various gas and liquid flow rates. Two of the studied prototypes presented higher holdup than the 5 ppi ceramic foam and the 15 mm Raschig rings for lower liquid rates. Prototypes also showed good results for pressure drop, with flooding reached at gas load factors above 3Pa(0.5). In terms of mass transfer efficiency, HETP results for the new prototypes remained between 0.35m and 0.45m, comparable to Mellapak 250Y.

Through Government Regulation No. 79, issued in 2014 on National Energy Development, the Indonesian government aimed to diversify raw materials from biomass, including rice straw, an abundant resource. To realize the national goals, farmers' participation in rice straw utilization and management plays an essential role in determining the direction and succession of these valorization programs by considering sustainability aspects. Statistical analysis by clustering methods using multiple correspondence analysis (MCA) and hierarchical agglomerative clustering (HAC) was employed to visualize and extract information about farmers' willingness and participation. The survey results of 300 farmers in three regions of East Java found that most farmers utilized rice straw in small portions, depending on the weather, for animal feed and planting purposes, such as mushroom media planting, fertilizer, and mulch. More than 60% of farmers have a significant perception that better rice straw management, when complemented by the government’s role in supporting physical and nonphysical facilities, will improve farmers' socioeconomic quality and mitigate greenhouse gas emissions. The findings of this study will help to minimize the challenges and barriers to bioenergy development and optimize their opportunities by continuing to synergize to set future strategies.

89Zr-immunoPET is a hot topic as 89Zr cumulates the advantages of 64Cu and 124I without their drawbacks. We report the synthesis of a model ligand of a chiral bioconjugable tetrahydroxamic chelator combining the desferriferrioxamine B siderophore and 1-hydroxy-2-piperidone ((PIPO)H), a chiral cyclic hydroxamic acid derivative, and the study by NMR spectroscopy of its zirconium complex. Nuclear Overhauser effect measurements (ROESY) indicated that the complex exists in the form of two diastereomers, in 77 : 23 ratio, resulting from the combination of the central chiralities at the 3-C of the (PIPO)H component and at the Zr4+ cation. The 44 lowest energy structures out of more than 1000 configurations/conformations returned by calculations based on density functional theory were examined. Comparison of the ROESY data and the calculated interatomic H⋅⋅⋅H distances allowed us to select the most probable configuration and conformations of the major complex.

This study investigates the effective interfacial area in a novel rotating packed bed (RPB) equipped with dual gas inlets instead of the conventional single-gas-inlet RPB. The aim is to enhance the mass transfer efficiency of gas-liquid contacting processes in RPBs by increasing the number of gas inlets to improve the spread of gas supply into the packing. The RPB is a promising gas-liquid contactor configuration known for its intensified mass transfer characteristics. However, the impact of additional gas inlets on the effective interfacial area of the packing remains unexplored. An experimental method assessed the interfacial area under varying operational conditions which include a liquid flow rate of 0.30-0.60 m3/h, a gas flow rate of 100-300 Nm3/h, and a rotation speed of 600-1000 rpm. At operating conditions covering the maximum rotation speed of 1400 rpm, gas flow and liquid flow rates of 300 Nm3/h and 0.60 m3/h respectively, the results showed that on average, 55 to 97% of the 2400m2/m3 specific packing area can be effectively utilized for gas-liquid mass transfer during separation operations using the RPB. Compared to results reported for single-gas-inlet RPBs using similar packings, the RPB with double gas inlet proved to provide higher utilization of the packing. By simply doubling the number of gas inlets, the findings provide valuable insights into optimizing RPB designs and operations which could enhance mass transfer efficiency for various chemical and environmental applications.

As rotating packed beds (RPBs) gain prominence in intensified mass transfer operations, efficient packing design is critical for optimizing performance. Traditional packing structures often face limitations in terms of pressure drop, wetting efficiency, and fluid distribution. 3D-printed packings offer new possibilities by allowing complex geometries tailored to specific fluid dynamics. This study presents a detailed comparison of the performance of standard wire mesh packings and an anisotropic 3D-printed packing, focusing on pressure drop variations under varying operational conditions. Compared to the standard packing, the hydrodynamic performance of the 3D printed packing showed a lower pressure drop of about 0.7kPa at the combination of maximum operating conditions investigated of 300Nm3/h, 1000 rpm, and 0.72m3/h in the gas flow, rotation speed, and liquid glow rate respectively. The wet pressure drop per unit packing length of the 3D packing compared favourably with the standard wire mesh packing. The 3D-printed RPB packings proved to be a promising way that has the potential to enhance the separation performance of RPBs.

Liquid distributor is an important internal in packed distillation columns. One of the key features of this equipment is the drip point density, which corresponds to the number of irrigation points per area of the cross-section. For gravity liquid distributors, increasing the number of irrigation holes generally requires small hole diameters, which makes the equipment more sensitive to plugging. In this work, we disclose a new gravity liquid distributor that achieves large drip point densities without requiring smaller irrigation holes. This distributor is an adaptation of the classic orifice-pan type, in which we add a tree-like structure made of wires to spread the liquid dripping from the orifices. The liquid flows outside the wires and splits several times over the different branching levels before falling on the packed bed. From an orifice-pan configuration with drip point density of 736 pts/m2, we designed and constructed enhanced distributors with a theoretical irrigation density of 14,800 pts/m2. Performance comparison using a recently disclosed structured packing shows that these enhanced distributors can decrease HETP from 0.45 m to 0.27 m. & COPY; 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

In conventional packed beds, mass transfer and flooding limitations lower the productivity of many processes. The almost zero sensitivity to variations in gravitational force has made centrifugal processes to have great potential for enhancing heterogeneous catalytic reactions. We studied a rotating packed bed (RPB) reactor as a gas/liquid contactor for multi-phase catalytic reactions. The scarcity of fundamental data on the hydrodynamics and mass transfer of the reactor limits the design, scale-up, and retrofitting of RPB reactors. Hence, we focused on the hydrodynamic behavior of the device. Previous studies on RPB reactor flooding and operating limits dwelled on visual observations and pressure drop variations only. However, physical visualizations are subjective because RPB reactor pressure drop variations are too inconsistent to be used to determine the upper operating limit during their operations. A robust quantitative method of obtaining RPB reactor flooding limits based on the flow rate of the ejected liquid, supported by visual observation and pressure drop measurement, was presented. The aim was to identify, with greater certainty, RPB reactor hydrodynamic characteristics and provide a more standard method of identifying it. The average increase in single-phase pressure drop per unit increase in rotation speed in the range investigated was 0.75Pa/rpm, and the average increase in pressure drop per unit increase in gas flow rate was 4.11Pa/Nm3h-1 within the operating range investigated.

Visual Abstract 227Th is a promising radioisotope for targeted α-particle therapy. It produces 5 α-particles through its decay, with the clinically approved 223Ra as its first daughter. There is an ample supply of 227Th, allowing for clinical use; however, the chemical challenges of chelating this large tetravalent f-block cation are considerable. Using the CD20-targeting antibody ofatumumab, we evaluated chelation of 227Th4+ for α-particle–emitting and radiotheranostic applications. Methods: We compared 4 bifunctional chelators for thorium radiopharmaceutical preparation: S-2-(4-Isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (p-SCN-Bn-DOTA), 2-(4-isothicyanatobenzyl)-1,2,7,10,13-hexaazacyclooctadecane-1,4,7,10,13,16-hexaacetic acid (p-SCN-Bn-HEHA), p-isothiacyanatophenyl-1-hydroxy-2-oxopiperidine-desferrioxamine (DFOcyclo*-p-Phe-NCS), and macrocyclic 1,2-HOPO N-hydroxysuccinimide (L804-NHS). Immunoconstructs were evaluated for yield, purity, and stability in vitro and in vivo. Tumor targeting of the lead 227Th-labeled compound in vivo was performed in CD20-expressing models and compared with a companion 89Zr-labeled PET agent. Results: 227Th-labeled ofatumumab-chelator constructs were synthesized to a radiochemical purity of more than 95%, excepting HEHA. 227Th-HEHA-ofatumumab showed moderate in vitro stability. 227Th-DFOcyclo*-ofatumumab presented excellent 227Th labeling efficiency; however, high liver and spleen uptake was revealed in vivo, indicative of aggregation. 227Th-DOTA-ofatumumab labeled poorly, yielding no more than 5%, with low specific activity (0.08 GBq/g) and modest long-term in vitro stability (<80%). 227Th-L804-ofatumumab coordinated 227Th rapidly and efficiently at high yields, purity, and specific activity (8 GBq/g) and demonstrated extended stability. In vivo tumor targeting confirmed the utility of this chelator, and the diagnostic analog, 89Zr-L804-ofatumumab, showed organ distribution matching that of 227Th to delineate SU-DHL-6 tumors. Conclusion: Commercially available and novel chelators for 227Th showed a range of performances. The L804 chelator can be used with potent radiotheranostic capabilities for 89Zr/227Th quantitative imaging and α-particle therapy.

Modern process equipment needed for safe and economically viable chemical and biological processes requires flexibility, compactness, and a great potential for enhancing mass transfer. Centrifugal process intensification equipment such as the rotating packed bed (RPB) satisfies the above mentioned requirements in addition to zero sensitivity to changes caused by gravity. The fundamental principles of RPBs are yet to be fully established due to difficulty in predicting their behavior which has necessitated the need for treating their design, modeling, and optimization on a case-to-case basis. This study focused on the hydrodynamics (pressure drops) of a pilot-scale RPB equipped with a stainless steel wire mesh packing. The effects of three operational parameters: average high gravity factor, integrated gas capacity factor, and liquid load, as well as a design parameter, the fluid distributor type were investigated. The maximum value of the average gravity factor used was 452. Also, a combined gas capacity factor of 2.6Pa0.5, and a liquid load of up to 20m3m-2h-1 were explored. Additionally, the influence of liquid distributor type on the pressure drop of RPBs was investigated.

Six- and seven-membered cyclic hydroxamic acids are found as terminal binding units in different families of siderophores, including exochelins and mycobactins. The simplest models of these preorganized chelating ligands were known, but their coordination chemistry with Fe3+, the target metal ion of siderophores, had never been reported. Four complexes were synthesized and studied: two Fe3+ complexes, one with the six-membered ring hydroxamate PIPO- and one with the seven-membered ring hydroxamate AZEPO(-), and the two corresponding Ga3+ complexes. X-ray diffraction studies showed that the interligand repulsion energies were better minimized in the case of the AZEPO(-) complexes whatever the metal cation considered, and that the Fe-O bond distances were shorter in [Fe(AZEPO)(3)] by comparison with [Fe(PIPO)(3)].