The Cover Picture shows a vortex of Cu(II) H2dmg (dimethylglyoxime) complexes of diverse nuclearity. The nuclearity is governed by the basicity during the reaction of Cu(II) and H2dmg; however, in ...solution, the complexes can be interconverted into each other using the influence of Brønsted/Lewis bases/acids. Notably, only the simultaneous modification of stoichiometric ratio and basicity will lead to interconversion. Furthermore, this equilibrium also can be exploited for the simple preparation of common Cu(I) salts. More details can be found in article 10.1002/zaac.202300253 (DOI: 10.1002/zaac.202300253) by Sabine Becker and co‐workers.
Mesoporous Na-LTA zeolite was synthesized using the surfactant templating method with the organosilane surfactant 3-(trimethoxysilyl)propyl octadecyldimethylammonium chloride (TPOAC). The formation ...of mesopores not only improved the accessibility of the basic catalytic sites but also led to the formation of isolated external silanols. These silanols were used to anchor propylamine groups by reacting with 3-aminopropyltrimethoxysilane (APTMS). The incorporation of propylamine groups in the mesoporous Na-LTA improved its catalytic activity in the Knoevenagel condensation reaction by 40 % due to the presence of extra basic catalytic sites from amino groups. The combination of mesopore generation and functionalization is an efficient strategy for enhancing the performance of Na-LTA zeolite in this reaction.
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•Mesoporous Na-LTA zeolite was synthesized by TPOAC templated method.•The formation of mesopores provides a high concentration of external silanols.•Silanols were used to anchor propylamine groups, adding extra basic sites on the zeolite.•Increased accessibility and basicity of the catalyst enhanced its catalytic activity in the Knoevenagel condensation.
Al30 is the polycation with the highest degree of polymerization and surface charge in the currently known structural aluminum species. It shows excellent coagulation performance in water treatment ...process, and has the characteristics of wide application range of pH and dosage. pH value is one of the most important factors affecting the aggregation and coagulation process of Al30, but the influence of Al30 aggregation reaction on its coagulation effect is still unclear. Therefore, this article reports the deprotonation and aggregation reaction of Al30 by adjusting the basicity (B) of the solution, particularly to further understand the coagulation mechanism of Al30 under different conditions. The results showed that in the base titration process, when B < 2.86 in 0.01 M Al30 solution as AlT (the concentration of total Al), deprotonation and preliminary aggregation mainly occurred; when B > 2.86, the size of Al30 aggregates (Al30agg) increased rapidly, forming gels and gradually transforming into Al(OH)3. In this process, in addition to the reduction of electrostatic repulsion induced by Al30 deprotonation, the oligomers generated by the partial dissociation of Al30 also play the role of bridging-connection. Under the experimental titration conditions, the Al30agg always maintained a positive zeta potential. In addition, Al30 can deprotonate and aggregate at lower pH, which is an important reason for its unique coagulation characteristics. The larger structure size of Al30 also made it easy to form branched aggregates, so that it can play an effective role in a wider dosage range without destabilization of colloids. This study gives an insight in the advancement of coagulants and promotes the industrial application and commercialization of functional coagulants based on polyaluminum.
•The process of Al30 aggregation and structural transformation was investigated.•Belt η-H2O in Al30 was the most active site for deprotonation and ion exchange.•The aggregation process of Al30 was divided into three sections.•Structure of Al30 kept stable in aggregating process.•Aggregation of Al30 influence its coagulation mechanism under different conditions.
This Perspective article highlights the recent development of mesoionic N-heterocyclic olefins (mNHOs), where the exo-cyclic olefinic carbon is not bonded to strongly electron-withdrawing groups. The ...unquenched basicity and nucleophilicity of the exo-cyclic olefinic carbon make mNHOs strong σ-donors and enable unique reactivity patterns.
This article highlights the recent advances in the field of mesoionic N-heterocyclic olefins (mNHOs).
•High yield and selectivity of fructose were achieved under exceptionally mild conditions.•Catalytic basicity was associated with CaO content and the extend of dolomite calcination.•A strategically ...designed basicity enhanced glucose conversion to fructose.•Demonstrated stable recyclability for at least three recycles.
Isomerization of glucose into fructose represents a crucial intermediate step in bio-refining because fructose serve as a more effective substrate than glucose for converting cellulosic biomass into biofuels and fine chemicals. In this study, we demonstrated the effectiveness of a solid base catalyst derived from natural dolomite through simple calcination, which is easily prepared, cost-effective, and recyclable. We investigated a series of prepared CaO/MgO catalysts with varied compositions, morphologies, textures and basicity. The optimal catalyst, prepared by calcination at 650 °C for 3 hours followed by 700 °C for 3 hours, achieved a glucose conversion of 42.3 %, a fructose yield of 35.9 %, and a fructose selectivity of 84.8 % at 35 °C for 60 min. For comparison, we also investigated CaO-MgO mixed oxides with varying molar contents of CaO for glucose isomerization. A multivariable linear regression model was applied to determine the optimal reaction conditions. The validated optimal conditions fell within the ranges of 6–9 mol% CaO content, 35–55 °C and 20–60 min. Under these conditions, a superior fructose yield of 35.6 % and a fructose selectivity of 76.1 % were achieved using a catalyst of 8 mol% CaO at 55 °C for 45 min. The basicity of catalyst, which has been shown to positively correlated with the CaO content in CaO-MgO mixed oxides and the degree of partial decomposition of dolomite (degree of calcination) during catalyst preparation, plays a significant role in catalytic performance. Moderate basicity is conducive to glucose conversion to fructose, whereas excessive basicity can lead to the formation of byproducts, thereby reducing fructose selectivity. Furthermore, both types of catalyst were confirmed to be reusable for at least three cycles. This study introduces a novel approach for utilizing nature dolomites and enhances the understanding of fructose production from glucose using solid base catalysts.
The solvation mechanisms of aspirin and etomidate in four combinations of Emim+ and BuGun+ paired with OAc− and NTf2− were systematically studied by molecular dynamics simulations and DFT ...calculations. It was shown that the favorable solvation of aspirin and etomidate correlated well with hydrogen‐bond (H‐bond) basicity of anions and the H‐bond acidity of cations, respectively. Wherein, the H‐bond between aspirin and OAc− anion with high H‐bond basicity possessed covalent feature, so ILs containing OAc− anion has the best effective in solubilizing aspirin. However, H‐bond interactions between etomidate and cations exhibited an electrostatic dominant, and moderate cation–anion interaction could weaken it. Accordingly, for etomidate, the best ILs solvent comprised a weakly interacting anion and a cation with strong H‐bond acidity, that is, BuGunNTf2. This solvation difference was because aspirin with carboxyl group displayed strongly H‐bond donating characteristic, whereas etomidate with no active hydrogen protons mainly formed H‐bond with cations. Additionally, we found that π–π stacking interactions were of secondary importance for the solubilization of etomidate, but little for aspirin. These simulations will be helpful for experimental design new ILs to solubilize some drugs with aspirin‐like or etomidate‐like structures.
Many PACl (poly-aluminum chloride) coagulants with different characteristics have been trial-produced in laboratories and commercially produced, but the selection of a proper PACl still requires ...empirical information and field testing. Even PACls with the same property sometimes show different coagulation performances. In this study, we compared PACls produced by AlCl3-titration and Al(OH)3-dissolution on their performance during coagulation-flocculation, sedimentation, and sand filtration (CSF) processes. The removal targets were particles of superfine powdered activated carbon (SPAC), which are used for efficient adsorptive removal of micropollutants, but strict removal of SPAC is required because of the high risk of their leakage after CSF. PACls of high-basicity produced by AlCl3-titration and Al(OH)3-dissolution were the same in terms of the ferron assay and colloid charge, but their performance in CSF were completely different. High-basicity Al(OH)3-dissolution PACls formed large floc particles and yielded very few remaining SPAC particles in the filtrate, whereas high-basicity AlCl3-titration PACls did not form large floc particles. High-basicity PACls produced by Al(OH)3-dissolution were superior to low-basicity PACl in lowering remaining SPAC particles by the same method because of their high charge neutralization capacity, although their floc formation ability was similar or slightly inferior. However, high-basicity Al(OH)3-dissolution PACl was inferior when the sulfate ion concentration in the raw water was low. Sulfate ions were required in the raw water for high-basicity PACls to be effective in floc formation. In particular, very high sulfate concentrations were required for high-basicity AlCl3-titration PACls. The rate of hydrolysis, which is related to the polymerization of aluminum species, is a key property, besides charge neutralization capacity, for proper coagulation, including formation of large floc particles. The aluminum species in the high-basicity PACls, in particular that produced by AlCl3-titration, was resistant to hydrolysis, but sulfate ions in raw water accelerated the rate of hydrolysis and thereby facilitated floc formation. Normal-basicity Al(OH)3-dissolution PACl was hydrolysis-prone, even without sulfate ions. Aluminum species in the high-basicity AlCl3-titration PACl were mostly those with a molecular weight (MW) of 1–10 kDa, whereas those of high-basicity Al(OH)3-dissolution PACls were mostly characterized by a MW > 10 kDa. Normal-basicity Al(OH)3-dissolution PACl was the least polymerized and contained monomeric species.
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•High-basicity PACl, esp. that made by AlCl3-titration, is resistant to hydrolysis.•AlCl3-titration PACl is inferior to Al(OH)3-dissolution PACl due to slow hydrolysis.•Sulfate ions in raw water affect the performance of high-basicity PACl.•High-basicity PACl requires sulfate ions, but normal-basicity PACl does not.•Hydrolysis and charge neutralization capacity are both needed for coagulation.
A new generation of solid superbases derived from potassium single atoms is described by You Han, Lin‐Bing Sun, and co‐workers in their Research Article (e202215157). The source of basicity is ...different from conventional basicity originating from oxygen and nitrogen atoms. Because of the superbasicity as well as high dispersion and anchoring of the basic sites, the potassium single atoms on graphene exhibit excellent catalytic activity and stability in transesterification reactions.
The effects of CaO/SiO2 ratio (basicity) and CaCl2 addition amount on the properties of CaO–MgO–Al2O3–SiO2–CaCl2 glass-ceramics (GC) were investigated. When sintered at 825 °C, the increase in ...basicity from 0.35 to 0.75 reduced the porosity of GCs from 1.1 to 0.8 vol%, but the increase of CaCl2 addition amount from 5 to 10 wt% increased the porosity from 0.8 to 7.0 vol%. The main crystalline phase of GC changed from augite (Ca(Mg0·7Al0.3) (Si1·7Al0.3)O6) to Ca10Al12Cl2Si5O37 by increasing the CaCl2 addition amount to 7.5 wt%. The increase in CaCl2 addition had adverse effects on the bending strength and Vickers hardness, while the rise in basicity deteriorated the bending strength but had little impact on the Vickers hardness. This study may have a guiding significance for preparing slag-based GCs and treating CaCl2-containing wastes.
