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Cesium (Cs) and rubidium (Rb) separation from brine is an important and application-oriented topic. 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) has been used for Cs and Rb extraction. However, the traditional extraction technology is base and acid consumed. In the present work, an innovative process for Cs and Rb extraction with t-BAMBP is developed, which consists of saponification, extraction, scrubbing and stripping. Both infrared spectrum and electrostatic potential analysis indicate the hydrogen of phenolic hydroxyl isdissociated from t-BAMBP during saponification and the oxygen of phenolic hydroxyl is the binding site for alkali metal ions. Saponified organic phase shows an excellent extraction effect for Cs+ and Rb+. The extraction reaches equilibrium in 5 min, with 99.5% Cs+and 46.7% Rb+ are loaded into the organic phase in the single-stage extraction. Slope method indicatesthe structure of the extraction complex is MOR·3ROH (M = Cs+, Rb+, K+), where the electrostatic attraction between M+ and the oxygen of phenolic hydroxyl is dominant, and the cation−π interaction has a significant effect also. The extraction complex of MOR·3ROH dissociates in the acid environment while scrubbing and stripping is completed. The Cs+ and Rb+ are separated from the mixture phase, the proton H bonds to the phenolic hydroxyl group, and the extractant is regenerated.

Since the outer surface interaction of Q[n]s (OSIQ, including self-, anion- and aromatic-induced OSIQs) was proposed in 2014, it has become the most important research area in our group to construct various Q[n]-based supramolecular frameworks via the OSIQ strategy. Herein, we report a novel supramolecular framework constructed using cucurbit[8]uril (Q[8]) and 4-sulfocalix[6]arene (SC[6]A). This Q[8]/SC[6]A-based supramolecular framework is a product via the perfect combination of self-, anion- and aromatic-induced OSIQs. This framework has the characteristics of easy preparation and high stability with the most important feature being the sequence selective capture of specific metal cations, such as common alkali- and alkaline earth metal ions, and renewability. Thus, this framework may be used in seawater desalination, potassium ion enrichment, radioactive cesium ion pollution source treatment, Gruinard's treatment or water softening and other applications.

An alkali metal gallium iodate, Cs3[Ga2O(I3O9)(IO3)4(HIO3)] (CGIO), was synthesized by the traditional hydrothermal method. Interestingly, CGIO revealed a novel I3O93− fundamental building block (FBB) constituted by two IO3 tetrahedrons and one IO5 polyhedron through sharing O atoms. The new I3O93− trimer forms a 0D [Ga2O(I3O9)(IO3)4(HIO3)]3− anion cluster together with the [Ga2O11]16− dimer and isolated IO3− units. The UV-vis-NIR diffuse reflectance spectrum of CGIO shows a wide bandgap of 4.05 eV, and the thermal stability could reach above 400 °C. First-principles calculations explicated that the optical properties of CGIO mainly originated from the iodate anion units with a calculated birefringence of 0.04 at 1064 nm.

Understanding the essential roles in adiponitrile hydrogenation is a significant factor to design sparkling nickel catalysts. A series of Ni/Al2O3 catalysts have been synthesized by the deposition-precipitation method and used for the selective hydrogenation of adiponitrile. The formation of Ni compositions and chemical structure of catalysts were modulated by the assistant precipitators. Characterizations including the XRD, N2 adsorption-desorption, TEM, XPS, H2-TPD, and NH3-TPD were carried out. Smaller particles could be obtained via the fast deposition of Ni2+ by NaOH in Ni/Al2O3-OH or the uniform crystal seeds by urea in Ni/Al2O3-U. Strong alkali and the formation of nickel hydroxide facilitated the generation of Ni0 with better H2 activation ability. Whilst huge amount of nickel species in oxidative state and strong acidity were simultaneously generated in Ni/Al2O3-U, leading to the easily cycloaddition by-products. Kinetic study revealed that adiponitrile hydrogenation is a second-order reaction with respect to adiponitrile. The numbers of Ni0 active sites and acid sites could be balanced by the precipitation and crystallization via different processes. The yield of 1,6-hexanediamine reached 75.0% at 90 oC by 20 wt% Ni/Al2O3-OH.

Summary Alkali and alkaline earth metals (AMs) play indispensable roles in dinitrogen activation and ammonia synthesis. AM oxides have been used as catalyst promoters for industrial ammonia synthesis, while AM metals are common reducing agents in dinitrogen fixation by organometallic complexes. With the strong push toward green ammonia synthesis, AM is now on a greater platform, playing a more prominent role in mediating dinitrogen reduction via a variety of processes that can be coupled with renewable energy harvest and storage. This perspective discusses the rich chemistry among AM, N2, H2, and NH3; summarizes the classic understandings and new exciting progress in the exploration of AM for both heterogeneous and homogeneous nitrogen fixation; and highlights the multifunctional roles of unconventional and reactive AM-containing materials for future greener ammonia synthesis.

Alkali metal poisoning has been a complex yet unresolved issue restricting the catalytic activity of NH3–SCR catalysts in industry to date. Herein, the effect of K deposition on the catalytic activ...

Recently, neutral cyanurate acid and negative (iso-)cyanurates (HxC3N3O3)(3–x)– (x = 0–2) with strong conjugated π-bonds have been proposed as a new possible type of structural motifs for exploring...

In the present work, based on the density functional theory and crystal structure prediction algorithms, we found novel structures of alkali metal orthocarbonates Li4CO4-C2/c, Na4CO4-C2/c, and K4CO...

A series of glass fibre doped Ce–W/TiO2 catalysts were investigated for the selective catalytic reduction of NOx by NH3. The adhesion and mechanical strength of the CeO2–WO3/TiO2 catalyst was greatly enhanced by the addition of 6% glass fibre. However, the glass fiber contains a small amount of alkali metals, which occupied the active site on the surface of the CeO2–WO3/TiO2 catalysts, thus the catalytic performance of catalyst was inhibited by the addition of glass fibre. Furthermore, BET, XRD, XPS, TPR and TPD methods revealed that the addition of glass fiber can inhibit the formation of catalyst pore structure and reduce the content of Ce3+, adsorbed oxygen and the Bronsted and Lewis acid sites on the catalyst surface, thereby affecting the redox abilities, nitrogen oxides and ammonia adsorption capacity of catalysts.

The syntheses of regioisomers of calix[6]crown-6 under a metal carbonate template were highly metal cation-dependent and the 1,2-bridged isomer (H4 L 1,2) catches Cs+ very efficiently in its deep and good-fit pocket similar to a baseball glove., We report the formation of heavy alkali metal complexes of bicyclic host molecules including the caesium(I) complex that catches the central metal ion with the deep pocket of the host similar to a baseball glove. For this, three regioisomers of singly bridged calix[6]crown-6 [1,2-bridged (H4 L 1,2), 1,3-bridged (H4 L 1,3) and 1,4-bridged (H4 L 1,4)] have been synthesized by alkyl­ation of calix[6]arene with penta­ethyl­ene glycol di­tosyl­ate in the presence of M 2CO3 (M = Na, K, Rb and Cs). The larger the cation size of the metal carbonate, the higher the yield of the H4 L 1,4 isomer, indicating the size-based template effect. A combination of H4 L 1,2 and RbOH allowed isolation of the mononuclear rubidium(I) complex (1) in which the metal center is six-coordinated in a loose fashion, the remaining two oxygen donors in the crown loop and two phenols in the calix rim are uncoordinated. Notably, the complexation of H4 L 1,2 with CsOH yielded the mononuclear caesium(I) complex (2), in which all possible ten binding sites on the deep and good-fit pocket participate in coordination via high cooperativity between the crown loop and calix rim, similar to a baseball glove. In dipolar organic solution, the caesium(I) complex 2 remains intact. H4 L 1,4 afforded a dicesium(I) complex (3) and adjacent complexes are linked by intermolecular cation–π interactions, giving rise to a pseudo one-dimensional coordination polymer. These results provide insight into the metal carbonate-dependent synthesis of calix[6]crowns and the influence of regioisomers on caesium(I) complexation.

Ultrabroad spectral absorption is required for semiconductor photocatalysts utilized for solar-to-chemical energy conversion. The light response range can be extended by element doping, but the photocatalytic performance is generally not enhanced correspondingly. Here we present a solid alkali activation strategy to synthesize near-infrared (NIR) light-activated carbon-doped polymeric carbon nitride (A-cPCN) by combining the copolymerization of melamine and 1,3,5-trimesic acid. The prepared A-cPCN is highly crystalline with a narrowed bandgap and enhanced efficiency in the separation of photogenerated electrons and holes. Under irradiation with NIR light (780 nm ≥ λ ≥ 700 nm), A-cPCN shows an excellent photocatalytic activity for H2 generation from water with rate of 165 µmol g−1 h−1, and the photo-redox activity for H2O2 production (109 µmol g−1 h−1) from H2O and O2, whereas no observed photocatalytic activity over pure PCN. The NIR photocatalytic activity is due to carbon doping, which leads to the formation of an interband level, and the alkali activation that achieved shrinking the transfer distance of photocarriers. The current synergistic strategy may open insights to fabricate other carbon-nitrogen-based photocatalysts for enhanced solar energy capture and conversion.

In this report, the geometric and electronic properties and static and dynamic hyperpolarizabilities of alkali metal-doped C6O6Li6 organometallics are analyzed via density functional theory methods. The thermal stability of the considered complexes is examined through interaction energy (Eint) calculations. Doping of alkali metal derives diffuse excess electrons, which generate the electride characteristics in the respective systems (electrons@complexant, e-@M@C6O6Li6, M = Li, Na, and K). The electronic density shifting is also supported by natural bond orbital charge analysis. These electrides are further investigated for their nonlinear optical (NLO) responses through static and dynamic hyperpolarizability analyses. The potassium-doped C6O6Li6 (K@C6O6Li6) complex has high values of second- (βtot = 2.9 × 105 au) and third-order NLO responses (γtot = 1.6 × 108 au) along with a high refractive index at 1064 nm, indicating that the NLO response of the corresponding complex increases at a higher wavelength. UV-vis absorption analysis is used to confirm the electronic excitations, which occur from the metal toward C6O6Li6. We assume that these newly designed organometallic electrides can be used in optical and optoelectronic fields for achieving better second-harmonic-generation-based NLO materials.

After exploring the potential energy surfaces of Mm CE2p (E=S-Te, M=Li-Cs, m=2, 3 and p=m-2) and Mn CE3q (E=S-Te, M=Li-Cs, n=1, 2, q=n-2) combinations, we introduce 38 new global minima containing a planar hypercoordinate carbon atom (24 with a planar tetracoordinate carbon and 14 with a planar pentacoordinate carbon). These exotic clusters result from the decoration of V-shaped CE22- and Y-shaped CE32- dianions, respectively, with alkali counterions. All these 38 systems fulfill the geometrical and electronic criteria to be considered as true planar hypercoordinate carbon systems. Chemical bonding analyses indicate that carbon is covalently bonded to chalcogens and ionically connected to alkali metals.

The mixed cation compounds Na1-xKxAsSe2 (x = 0.8, 0.65, 0.5) and Na0.1K0.9AsS2 crystallize in the polar noncentrosymmetric space group Cc. The AAsQ2 (A = alkali metals, Q = S, Se) family features one-dimensional (1D) 1/∞[AQ2-] chains comprising corner-sharing pyramidal AQ3 units in which the packing of these chains is dependent on the alkali metals. The parallel 1/∞[AQ2-] chains interact via short As···Se contacts, which increase in length when the fraction of K atoms is increased. The increase in the As···Se interchain distance increases the band gap from 1.75 eV in γ-NaAsSe2 to 2.01 eV in Na0.35K0.65AsSe2, 2.07 eV in Na0.2K0.8AsSe2, and 2.18 eV in Na0.1K0.9AsS2. The Na1-xKxAsSe2 (x = 0.8, 0.65) compounds melt congruently at approximately 316 °C. Wavelength-dependent second harmonic generation (SHG) measurements on powder samples of Na1-xKxAsSe2 (x = 0.8, 0.65, 0.5) and Na0.1K0.9AsS2 suggest that Na0.2K0.8AsSe2 and Na0.1K0.9AsS2 have the highest SHG response and exhibit significantly higher laser-induced damage thresholds (LIDTs). Theoretical SHG calculations on Na0.5K0.5AsSe2 confirm its SHG response with the highest value of d33 = 22.5 pm/V (χ333(2) = 45.0 pm/V). The effective nonlinearity for a randomly oriented powder is calculated to be deff = 18.9 pm/V (χeff(2) = 37.8 pm/V), which is consistent with the experimentally obtained value of deff = 16.5 pm/V (χeff(2) = 33.0 pm/V). Three-photon absorption is the dominant mechanism for the optical breakdown of the compounds under intense excitation at 1580 nm, with Na0.2K0.8AsSe2 exhibiting the highest stability.

The properties of metal/dioxygen species, which are key intermediates in oxidation catalysis, can be modulated by interaction with redox-inactive Lewis acids, but structural information about these adducts is scarce. Here we demonstrate that even mildly Lewis acidic alkali metal ions, which are typically viewed as innocent "spectators", bind strongly to a reactive cis-peroxo dicopper(II) intermediate. Unprecedented structural insight has now been obtained from X-ray crystallographic characterization of the "bare" CuII2(μ-η1:η1-O2) motif and its Li+, Na+, and K+ complexes. UV-vis, Raman, and electrochemical studies show that the binding persists in MeCN solution, growing stronger in proportion to the cation's Lewis acidity. The affinity for Li+ is surprisingly high (∼70 × 104 M-1), leading to Li+ extraction from its crown ether complex. Computational analysis indicates that the alkali ions influence the entire Cu-OO-Cu core, modulating the degree of charge transfer from copper to dioxygen. This induces significant changes in the electronic, magnetic, and electrochemical signatures of the Cu2O2 species. These findings have far-reaching implications for analyses of transient metal/dioxygen intermediates, which are often studied in situ, and they may be relevant to many (bio)chemical oxidation processes when considering the widespread presence of alkali cations in synthetic and natural environments.

Rare-earth (RE) containing alkali aluminoborosilicate glasses find increasingly broad technological applications, with their further development only impeded by yet-poor understanding of coordination environment and structural role of RE ions in glasses. In this work we combine free induction decay (FID)-detected electron paramagnetic resonance (EPR), electron spin echo envelope modulation (ESEEM), and MAS NMR spectroscopies, to examine the coordination environment and the clustering tendencies of RE3+ in a series of peralkaline aluminoborosilicate glasses co-doped with Nd2O3 (0.001-0.1 mol%) and 5 mol% La2O3. Quantitative EPR spectral analysis reveals three different Nd3+ forms coexisting in the glasses: isolated Nd3+ centers, dipole-coupled Nd clusters (Nd-O-X-O-Nd, where X = Si/B/Al), and spin-exchange-coupled Nd clusters, (Nd-O-Nd) and (Nd-O-La-O-Nd). Extensive RE clustering is observed at high RE2O3 concentrations, with more than 90% REs converting to dipole- and exchange-coupled Nd clusters already at [RE2O3] = 0.01 mol%. ESEEM analysis of the EPR-detectable Nd centers indicates a Na/Si-rich environment (four Na+ per Nd3+) for the isolated Nd3+ centers and the Na/Si/B-rich environment (2-3 Na+ and 1-2 boron per each Nd3+) for the dipole-coupled Nd clusters, while the EPR-undetectable exchanged-coupled RE clusters are predicted to exist in a Na/B-rich environment. The RE clustering induces nano-scale glass phase separation, while the Na/B-rich environment of the RE clusters implies a depletion of the same elements from the remaining host glass. Based on our results, we develop a mechanistic model that explains the high tendency of RE3+ to form clusters in alkali aluminoborosilicate glasses.

2-Azidobenzoic acid has undergone rearrangement into 2-[(2-carboxyphenyl)amino]-6-formylnicotinic acid under irradiation in aqueous-organic media in the presence of acetates of alkali or alkaline earth metals. The structure of the resulting compound has been elucidated by methods of mass and NMR spectroscopy.

Abstract Sodium and potassium tert-butyl peroxide hydrates 2Na+·2C4H9$${\text{O}}_{2}^{ - }$$·7H2O (I) and 2K+· 2C4H9$${\text{O}}_{2}^{ - }$$·4H2O (II) were prepared. According to X-ray diffraction data (CIF files CCDC no. 2081025 (I) and no. 2081024 (II)), the compounds are coordination polymers in which alkali metal atoms have C.N.(Na) of 6 or C.N.(K) of 6 and 8. The crystal packings comprise layers with clearly defined hydrophobic surfaces consisting of hydrocarbon groups and hydrophilic inner areas including water molecules, alkali metal cations, and peroxy groups of the tert-butyl peroxide anions. Compounds were characterized by vibrational spectroscopy, 1H, 13C NMR spectroscopy, thermogravimetry, and differential scanning calorimetry.

Understanding electronic structures is important in order to interpret and to design the chemical and physical properties of solid-state materials. Among those materials, tellurides have attracted an enormous interest, because several representatives of this family are at the cutting edge of basic research and technologies. Despite this relevance of tellurides with regard to the design of materials, the interpretations of their electronic structures have remained challenging to date. For instance, most recent research on tellurides, which primarily comprise post-transition elements, revealed a remarkable electronic state, while the distribution of the valence electrons in tellurides comprising group-I/II elements could be related to the structural features by applying the Zintl-Klemm-Busmann concept. In the cases of tellurides containing transition metals the applications of the aforementioned idea should be handled with care, as such tellurides typically show characteristics of polar intermetallics rather than Zintl phases. And yet, how may the electronic structure look like for a telluride that consists of a transition metal behaving like a p metal? To answer this question, we examined the electronic structure for the quaternary RbTbCdTe3 and provide a brief report on the crystal structures of the isostructural compounds RbErZnTe3 and RbTbCdTe3, whose crystal structures have been determined by means of X-ray diffraction experiments for the very first time.

International audience; The relationship between concentration of sodium cations and the properties of faujasite (FAU) zeolite using a two-step synthesis procedure including (1) formation of amorphous aluminosilicate precursors and separation of amorphous nanoparticles, and (2) transformation of these amorphous particles into zeolite crystals by treatment with alkali solutions (NaOH) were studied. Three representative samples including two nano-sized zeolites and one micron-sized zeolite were prepared using different concentration of sodium hydroxide. The crystallization process of these zeolites was studied in details by FTIR, NMR, XRD, SEM, TEM, N 2 adsorption. The results indicated that minor changes in the concertation of inorganic cations can significantly shorten the induction period and crystallization time and thus affect the morphology, size and chemical composition of the zeolite crystals.

The interaction between methyl ester sulfonate (MES) surfactant and polyacrylamide (PAM) polymer in alkaline-surfactant-polymer (ASP) flooding due to electrostatic charges and hydrophobicity of both elements at the interface was investigated. In the ASP flooding, sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) were used as alkali. At high PAM concentrations, the strong hydrophobic interaction between the PAM backbone and the carbon chain of MES destabilizes surfactant packing at the interface, increasing interfacial tension (IFT). The higher conductivity value of the ASP slug (15 mS/cm) compared to the alkali-surfactant (AS) slug (7 mS/cm) indicates a strong electrostatic interaction caused by the rapid mobilization of free surfactant molecules across the PAM backbone at the water-oil interface. The lowest IFT value for ASP flooding was 0.28 mN/m. Sand pack flooding tests showed that the optimum PAM concentration in ASP flooding was 1,000 ppm, resulting in a 20–35% oil recovery. A negative effect of PAM on the oil recovery was observed at a higher PAM concentration of 9,000 ppm. IFT and mobility ratios were irregularly related to the oil recovery. At 1,000 ppm PAM, the oil recovery for ASP slug with MES and commercial surfactant sodium dodecyl sulfate (SDS) was 25% and 20%, respectively, indicating that MES is superior to SDS.

Nanocrystalline powders of alkali metal titanates were prepared using titanium tetraisopropoxide and alkali metal salts by a sol–gel method. The influences of the kinds of alkali metal salts and heating temperature on the reaction of the titanium precursor compounds with the alkali metal salts, its phase transition, and crystal growth were investigated by thermal analyses, XRD measurement, and SEM observation in order to prepare lithium, sodium, and potassium titanates at relatively low temperatures. The amorphous titania gel or its product, very small titania crystals, as an intermediate phase reacted with the alkali metal salts at around 500–600 °C while it was still highly active and formed alkali metal titanate nanoparticles before forming the stable titania crystals. It is important that the active amorphous titania gels react with the dispersed alkali metal salts at a temperature as low as possible in order to form the alkali metal titanate nanocrystals.

Transition-metal containing halides with Ruddlesden-Popper (RP) perovskite structures have received extensive attention owing to their emerging and anisotropic photoelectric functionalities. Among them, A2 CuX4 (A=alkali metal or organic cations, X=Cl, Br, I) series are particular, because of the Jahn-Teller distortion of Cu2+ sensitive to external stimuli such as temperature and pressure. In this article, we report the structure evolution and physical property responses of RP perovskites Rb2 CuCl4-x Brx (x=1, 2) to external pressure. Dramatic structural phase transitions from orthorhombic to monoclinic occur around 3.0 GPa in both materials regardless of their distinct compositions. Structure analyses reveal the suppression and final vanishing of the Jahn-Teller distortion of Cu2+ cations under compression and crossing the phase transition, respectively. Rb2 CuCl4-x Brx perovskites exhibit abrupt bandgap narrowing (from reddish-brown to black) along with the structural phase transition, and an overall bandgap narrowing of 75% up to ∼27 GPa but still keeping semiconductive. During the compression processes, the resistances of Rb2 CuCl4-x Brx have been greatly reduced by 5-orders of magnitude. Moreover, all of the pressure-induced phenomena in Rb2 CuCl4-x Brx perovskites are reversible upon decompression and no obvious difference is observed for the pressure responses between [CuCl4 Br2 ] and [CuCl4 (Cl,Br)2 ] coordination environments. The impact of pressure on the structural and physical properties in two-dimensional Rb2 CuCl4-x Brx provides in-depth understanding on the structure design of functional halide perovskites at ambient conditions.

Two-dimensional (2D) nanomaterials have received a significant research attention owing to their unique chemical and physical properties. These materials not only provide the chemically active sites and exposed surface atoms, but also display the porous nature suitable for their use as membranes for gas separation. In this study, 3D CAU-10-H has been transformed into a novel alkali stabilized 2D CACl-10 (180). Though CACl-10 (180) is similar to AlOOH, it is a novel 2D nanomaterial synthesized by using 4-chloroisophthalic acid and aluminum nitrate nonahydrate, with thermal decomposition at 300 °C. Further, CACl-10 (180) is noted to retain its framework structure in strong alkali solutions, attributed to the alkali-resistant aluminum hydroxide. At the same time, it has been demonstrated that 3D CAU-10-H can also transform into 3D CACl-10 (140) and 3D CACl-10 (130), and the halogen atoms of the ligands (-Cl) affect the alkali stability of the materials. Subsequently, the PVAm-CACl-10 (180)/MPSf mixed matrix membranes were prepared and applied for CH4 /N2 separation. The developed membrane exhibits the CH4 permeance of 1647.99 GPU with a CH4 /N2 selectivity of 3.1. As a result, 2D CACl-10 (180), with a strong alkali stability and an acceptable CH4 /N2 membrane separation performance, represents a high potential of application in the membrane separation process.

Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) havebeen computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.

Ethanol Guerbet condensation (EGC) is a green process for preparing n-butanol and the development of highly effective solid catalysts is still the bottleneck of this reaction. In this work, a series of multifunctional catalysts Ni–X/TiO2 (X = Ru, Pt, Ir, Au, Cu, Mn, Co, Fe) were prepared by a co-impregnation method in order to improve the catalytic performance, especially the stability. It was found that the addition of the second metal component changed the acidity and alkalinity of Ni/TiO2 catalyst. What is more, acid site number affected ethanol conversion while alkali site number affected n-butanol selectivity. Among the Ni–X/TiO2 catalysts, Ni–Cu/TiO2 showed the best catalytic performance. The effects of preparation conditions on the catalytic performance of Ni–Cu/TiO2 were investigated and the results showed that the suitable preparation conditions were as follows: a Ni/Cu mass ratio of 59 : 1, a Ni–Cu loading of 12.5 wt %, a calcination temperature of 450°C, a calcination time of 2 h, a reduction temperature of 400°C, and a reduction time of 4 h. At a 10 wt % of catalyst loading, a reaction temperature of 210°C and a reaction time of 10 h, the ethanol conversion and the selectivity of n-butanol were 47.9 and 44.4%, respectively. Moreover, the stability of Ni–Cu/TiO2 catalyst was greatly improved due to the interaction between Ni and Cu as compared with the Ni/TiO2 catalyst: the catalytic activity of Ni–Cu/TiO2 did not decline significantly for reuse in three cycles.

A procedure for the synthesis of 2-anilino-6-hydroxy-3-phenylpyrimidin-4(3H)-one (mafedine) without using alkali metal ethoxides has been developed and optimized. Mafedine-related compounds that can be formed as possible impurities have been prepared, and conditions for joint determination of these impurities by HPLC with spectrophotometric detection have been found. The structure of the mafedine decomposition product in solution has been identified by HPLC-ESI/MS.

Single crystal diamond particles were heated with liquid phase alkali metals (Li, Na, K) in an argon atmosphere. It was found that Li reacts with the diamond above 600 degrees C, Na makes the surface rougher on a nm scale at 800 degrees C, and K did not change the surface morphology. The etching speed by the reaction with Li is the fastest on the (001) surface. Photoluminescence of the NV- (negatively charged nitrogen vacancy) center decreased only after the annealing with K. DFT calculations explained the strong chemical interaction between Li and the diamond (001) surfaces, and upward band bending at the interfaces with Na and K. The behavior of the NV-center photoluminescence is consistent with the extent of band bending. (C) 2021 Elsevier Ltd. All rights reserved.

At present, non-fuel utilization as alternative chemical feedstocks becomes very important and significant for the efficient conversion of lignite. To reduce CO2 production, an oxy-cracking technique in weak alkaline aqueous was conducted to selectively depolymerize Xilinguole lignite (XL) into humic acid (HA) under mild condition in this paper. The results indicated that XL has high reactivity, and can be depolymerized into HA with very little CO2. Elevated temperature is favorable for cracking of XL and converting HA into small molecular water-soluble acids and CO2. KOH mainly catalyzes the oxidative depolymerization of XL macromolecular structure. Lower temperature can reduce the formation of CO2 and the usage of alkali. Under 80°C, KOH/XL = 0.33 and 2 h, HA weight yield was the highest, reaching 81%, as well as no CO2 detected. Further, the obtained HA was separated and characterized by FTIR, CPMAS 13C-NMR, TG/DTG and element analyses. Compared to XL and oxidized residue, HA contains more OH and COOH groups and aromatic rings, and less aliphatic groups. Due to low alkali usage and negligible CO2, the oxidative depolymerization of XL to produce HA shows high utilization efficiency of carbon, and is a promising clean and efficient utilization approach.

Adjusting the interlayer structure of carbon nitride is expected to adjust its physicochemical properties, thereby enhancing photocatalytic activity. In this paper, alkaline metal ion-intercalated carbon nitride was prepared by molten salt co-pyrolysis. Alkali metal ions acted as mediators to provide a new migration path for the photogenerated electrons of g-C3N4. The intercalation of K+ and Na+ reduced the bandgap value of carbon nitride, expanded the visible light absorption range, and promoted the separation and migration of charge carriers. As a result, the hydrogen production rate of DCN1 reached 500 μmol g−1 h−1, which was 10 times than that of pristine g-C3N4. Experimental and theoretical methods were used to explain the improvement of photocatalytic efficiency after K+ and Na+ were intercalated into the interlayer of g-C3N4. Our work provided a new idea for the design of high-efficiency hydrogen evolution photocatalysts via intercalation method.

Calcium sulfoaluminate (CSA) cements, as one of the most promising low-CO2 alternatives to Portland cements, have been receiving increasing attention worldwide. Aluminum hydroxide (AH3) gel is a vi...

A series of 11 compounds, including alkali (Li, Na, K, Rb, Cs) and alkaline-earth (Mg, Ca, Sr, Ba) coordination polymers, transition-metal (Cu, Cd) complexes, and the ammonium salt of 3,5-dimethylp...

The extent to which carbon dioxide (CO2) mineralization (“carbonation”) using alkaline solids can reduce atmospheric CO2 concentrations is dictated by the rate of divalent alkaline metal release fr...

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms ($\rm Na$ and $\rm K$) to produce a mixed alkali honeycomb layered oxide material, namely, $\rm NaKNi_2TeO_6$. Via transmission electron microscopy measurements, we reveal the local atomic structural disorders characterised by aperiodic stacking and incoherency in the alternating arrangement of $\rm Na$ and $\rm K$ atoms. We also investigate the possibility of mixed electrochemical transport and storage of $\rm Na$ and $\rm K$ ions in $\rm NaKNi_2TeO_6$. In particular, we report an average discharge cell voltage of about $4\, \rm V$ and a specific capacity of around $80\, \rm mAh\, g^{-1}$ at low specific currents (i.e., $< 10\, \rm mA\, g^{-1}$) when a $\rm NaKNi_2TeO_6$-based positive electrode is combined with a room-temperature $\rm NaK$ liquid alloy negative electrode using an ionic liquid-based electrolyte solution. These results represent a step towards the use of tailored cathode active materials for dendrite-free electrochemical energy storage systems exploiting room-temperature liquid alkali metal alloy materials., 39 Pages, 7 Figures, 1 Cover Art

This work describes the currently known cationic-anionic and complex metal compounds containing the decachloro-closo-decaborate anion [B10Cl10]2–. The influence of the nature of the cation, solvent, metal and/or organic ligands on the composition and structure of the reaction products is discussed. Salts and complexes containing alkali metal cations, organic cations, and cationic complexes of metals Ag(I), Cu(II), Fe(II), Co(II), Ni(II), and Mn(II) with the decachloro-closo-decaborate anion as a counterion are described. The first examples of silver(I) complexes with the coordinated [B10Cl10]2– anion are described. The ability of the perchlorinated closo-decaborate anion to participate in additional non-bonded interactions B–Cl…X (X = C, N, O) with alkali metal cations, organic cations, organic ligands, and solvent molecules is discussed; these interactions can be identified by 35Cl NQR spectroscopy and X-ray diffraction. A number of new compounds based on perchlorinated boron clusters [B10Hal9R]– containing nine halogen atoms and a functional group R are discussed.

This study presented the lignin amine/cellulose acetate (LA/CA) nanofibers prepared by centrifugal spinning for heavy metal ion adsorption. First, lignin alkali is modified by Mannich reaction to prepare lignin amine with amino content of 16 mmol/g, and then the lignin amine was mixed with cellulose acetate to spin LA/CA nanofibers by centrifugal spinning. The effects of spinning parameters and lignin amine content on LA/CA nanofibers morphology were discussed. The optimum performing LA/CA nanofibers with the highest lignin amine content (1.6 wt.%) and the smallest average diameter (756 nm) were obtained when the spinneret rotating speed was about 6000 rpm, collection distance of 15 cm and spinneret hole diameter of 0.16 mm at room temperature. The obtained optimum LA/CA nanofibers were used to adsorb Cu(II) and Co(II) ions, and the influence of temperature, absorb time and initial pH of adsorption system on the adsorption capacity of the nanofibers were analyzed. Furthermore, the adsorption behavior of heavy metal ions Cu(II) and Co(II) was investigated. The results showed that the LA/CA nanofibers presented a quite high adsorption selectivity for Cu(II), the adsorption rates of LA/CA nanofibers to Cu(II) and Co(II) were mainly controlled by chemical adsorption and the adsorption mode was single molecular layer adsorption.

The main aim of this work was to study the effect of surface modification on the characteristics of local Pine cone flour (PCF) and on the interfacial adhesion in polypropylene/poly(lactic acid)/Pi...

pH shift is an effective technique for modifying functional properties of food proteins. However, it can increase lysinoalanine (LAL) content under alkali conditions, thus limiting the use of proteins. This study investigated the inhibition effect of ultrasonic parameters on LAL formation in rapeseed protein isolates (RPI) during pH shift treatment (pH-ST). Results showed that the content of LAL decreased by 49.5% and 74.1%, following the use of ultrasound (28 kHz, 40 W/L, 40 °C, and 30 min) under alkali and acidic treatment, respectively. Structural analysis showed that after ultrasonic irradiation, increased sulfhydryl groups and amino acids reduced the dehydroalanine and, thus, decreased LAL content. Particle size, secondary structure, and microstructure (SEM, AFM) analyses showed relative dispersion in protein distribution, reducing intermolecular or intramolecular cross-linking, thereby lowering the LAL content. Thus, ultrasonic-aided pH-ST may be an operational technique toward minimizing LAL formation in RPI.

We report the formation and full characterization of weak adducts between Li+ and Na+ cations and a neutral iron(0) complex, [Fe(CO)3(PMe3)2] (1), supported by weakly coordinating [BArF20] anions, [1·M][BArF20] (M = Li, Na). The adducts are found to synergistically activate aliphatic C-X bonds (X = F, Cl, Br, I, OMs, OTf), leading to the formation of iron(II) organyl compounds of the type [FeR(CO)3(PMe3)2][BArF20], of which several were isolated and fully characterized. Stoichiometric reactions with the resulting iron(II) organyl compounds show that this system can be utilized for homocoupling and cross-coupling reactions and the formation of new C-E bonds (E = C, H, O, N, S). Further, we utilize [1·M][BArF20] as a catalyst in a simple hydrodehalogenation reaction under mild conditions to showcase its potential use in catalytic reactions. Finally, the mechanism of activation is probed using DFT and kinetic experiments that reveal that the alkali metal and iron(0) center cooperate to cleave C-X via a mechanism closely related to intramolecular FLP activation.

Ash-rich sludge samples originating in four large plants were analyzed and employed to explore primarily the kinetics and the chemistry of devolatilization. A gravimetric, slowly increasing-temperature method was used in the range 298–1,123 K in a milieu of nitrogen. As an intricate combination of numerous (bio)organic and inorganic compounds, the dry sludge commences devolatilizing at approximately 418 K. The bulk of organic matter is released up to 823 K, at the rate becoming very slow thereafter. Basic constituents of the product gas are CO2, CO, H2, and CH4 with undesired nitrogenous, sulfurous, and chloro compounds. The residual solids contain significant amounts of organic matter/carbon and, on account of their favorable textural characteristics, they can be viewed as promising sorbents or catalysts. Kinetic triad was inferred from the experimental data: the model is well-capable of simulating the process of devolatilization and can be used for design considerations. An explicit equation, based upon a tractable approximation to the temperature integral (for [E/(RT)]≥0.1), has been verified and proposed for predicting the maximum reaction rate temperature. Remarkable differences in thermal behavior were explored in detail between the sludge and the alkali bicarbonates.

Lithium metal batteries are considered a promising candidate for high-energy-density energy storage. However, the strong reducibility and high reactivity of lithium lead to low Coulombic efficiency when contacting oxidants, such as lithium polysulfide caused by the serious "shuttle effect" in lithium-sulfur batteries. Herein we design selectively permeable lithium-ion channels on lithium metal surface, which allow lithium ions to pass through by electrochemical overpotential, while the polysulfides are effectively blocked due to the much larger steric hindrance than lithium ions. The selective permeation of lithium ions through the channels is further elucidated by the molecular simulation and visualization experiment. Consequently, a prolonged cycle life of 75 cycles and high Coulombic efficiency of 99 % are achieved in a practical Li-S pouch cell with limited amounts of lithium and electrolyte, confirming the unique role the selective ion permeation plays in protecting highly reactive alkali metal anodes in working batteries.

We report the successful electrochemical intercalation of F-ions into a densely packed perovskite oxide from a liquid electrolyte at room temperature. Using galvanostatic oxidation and electrochemical impedance spectroscopy coupled with operando X-ray diffraction, we show that roughly 0.5 equivalents of F-ions can be inserted onto the vacant A-site of the perovskite ReO3. Density functional theory calculations indicate that the intercalated phase is thermodynamically unfavorable compared to other less densely packed polymorphs of ReO3F. Pairing X-ray spectroscopy, neutron total scattering measurements, and magic-angle spinning 19F NMR confirms a rapid decomposition of the product on removal from the cell but nevertheless, these results clearly demonstrate that small anions like fluoride can be intercalated into solids as readily as alkali cations at room temperature, which opens new opportunities to electrochemically fluorinate many new materials.

To improve ionic conductivity, solid-state electrolytes with polarizable anions that weakly interact with mobile ions have received much attention, a recent example being lithium/sodium-rich antiperovskite M3HCh (M = Li, Na; Ch = S, Se, Te). Herein, in order to clarify the role of anions in antiperovskites, the M3FCh family, in which the polarizable H- anion at the octahedral center is replaced by the ionic F- anion, is investigated theoretically and experimentally. We unexpectedly found that the stronger attractive interaction between F- and M+ ions does not slow down the M+ ion diffusion, with the calculated energy barrier being as low as that of M3HCh. This fact suggests that the low-frequency rotational phonon modes of the octahedron of cubic M3FCh (and M3HCh) are intrinsic to facilitate the fast ionic diffusion. A systematic analysis further reveals a correlation between the tolerance factor t and the ionic transport: as t decreases within the cubic phase, the rotational mode becomes softer, resulting in the reduction of the migration energy. The cubic iodine-doped Li3FSe has a room-temperature ionic conductivity of 5 × 10-5 S/cm with a bulk activation energy of 0.18 eV.