Basic Sodium Research Articles

Development of Sterically Hindered and Basic Sodium Amides for Catalytic Hydrogen Isotope Exchange

AbstractSodium amides are gaining momentum in synthetic chemistry, emerging not only as more sustainable alternatives to lithium amides but also as superior reagents in synthesis and catalysis. Despite recent advances in sodium organometallics, the information available about the constitution of these reagents is very limited. Advancing the understanding on structure/reactivity correlations in sodium amide chemistry, here, we report the synthesis and characterisation of four new sodium amides, with different sterically demanding substituents (adamantyl/trimethylsilyl and dicyclohexyl groups at the nitrogen atom) and different polyamine donors as well as investigate their ability to promote catalytic hydrogen isotope exchange using deuterated benzene as deuterium source. These studies have revealed that sodium dicyclohexylamide in combination with PMDETA (N,N,N’,N’’,N’’‐pentamethyldiethylentriamine) offers only slightly lower deuterium incorporation for non‐activated arenes than sodium 2,2,6,6‐tetramethylpiperidide, which is significantly more expensive and less available.

Familial Hypophosphatemic Rickets: A Case Report and Review of the Literature

Among the genetic disorders causing rickets because of hypophosphatemia, X- X-linked dominant hypophosphatemic rickets (XLH) is the most common, with a prevalence of 1/20,000. The defective gene is on the X chromosome, but female carriers are affected, so it is an X-linked dominant disorder. XLH associated with short stature during childhood are mostly referred to the hospital & diagnosed as vit-D deficiency rickets & received vit D before adulthood. We presented a 2-year-old boy with the complaint of walking difficulties since his 1 year of age. The patient was assessed for sociodemographic, hematological & biochemical parameters. All imaging, Laboratory parameters and positive family history confirmed the diagnosis of XLH. We treated the patient with Di basic sodium phosphate solution and 1, 25 vit D. XLH needs a good assessment, care and follow-up through a complementary medical team. Bangabandhu Sheikh Mujib Med. Coll. J. 2024;3(1):52-55

Supported sodium aluminate catalysts effectively catalyze biodiesel synthesis

Strongly basic sodium aluminate (NaAlO2) was supported on titanium dioxide, γ-alumina, and hydrotalcite by impregnation. The resulting catalysts showed improved specific activity in the transesterification of sunflower oil in methanol, as compared to the unsupported NaAlO2. Even with small sodium aluminate loading (i.e. 2.3% up to 9.4%) valuables fatty acid methyl esters (FAME) yields can be obtained. In particular, 9.4SA-HT shows the best catalytic activity achieving a 70% yield after 240 min of reaction, with a mere catalyst loading of 1.5% wt (with respect to the oil mass) in the reaction media. Innovatively, a detailed correlation between the amount, strength, and nature of the basic sites and the support type is proposed. In particular, it is demonstrated that only a part of the basic sites is effectively available for catalysis because of the already adsorbed atmospheric CO2. Thus, a combination of effective availability and strength of the active species is pivotal for a high catalytic performance in the synthesis of biodiesel from triglycerides.

A MOF-doped molecularly imprinted polymer/MOF hybrid gel incorporating with pH-buffering sodium acrylate for practical detoxification of organophosphorus nerve agents

The fatal toxicity of organophosphorus nerve agents (ONAs) and the realistic condition of chemical attack occurring place trigger the urgent need to develop catalyst materials with degrading ability under the natural environment without bulk water and bases. Here, we strategically design a molecularly imprinted polymer (MIP)/MOF hybrid catalyst material by integrating enzyme-mimic MIP with Zr-MOF UiO-66-NH2 which demonstrate promising catalytic performance for degradation of ONAs. Furthermore, sodium acrylate functions as a hydrophilic and alkaline functional unit together with pyridine-amidoxime based functional monomers (PAAO) to copolymerize into molecularly imprinted polymeric network. The basic sodium carboxylate groups were installed near the active sites to provide appropriate alkaline microenvironment, non-bulk water and acid buffer capacity for the catalysis in pure water. The resultant MIP/MOF composite catalyst demonstrate outstanding catalytic activities in both liquid and solid phase hydrolysis of ONAs. Specifically, the half-life of liquid phase hydrolysis catalyzed by MIP/UiO-66-NH2-0.5 achieves 9.4 min for diethyl-4-nitrophenyl phosphate (DENP) and 10 min for dimethyl 4-nitrophenyl phosphate (DMNP), and solid-state hydrolysis present rapid degradation efficiency with a half-life of 28.6 min. In addition, composite catalyst MIP-Ag/UiO-66-NH2-0.5 that retains substrate selectivity of MIP, enables the simultaneous degradation of two types of organophosphorus substrates (phosphate and thiophosphate) by MIP and MOF in a synergistic way. Summarily, this work displays promising potential of MIP/MOF hybrid enzyme-like catalyst as effective and practical material for the practical protection and detoxification of organophosphorus nerve agents.

New Frontiers in Organosodium Chemistry as Sustainable Alternatives to Organolithium Reagents

AbstractWith their highly reactive respective C−Na and N−Na bonds, organosodium and sodium amide reagents could be viewed as obvious replacements or even superior reagents to the popular, widely utilised organolithiums. However, they have seen very limited applications in synthesis due mainly to poor solubility in common solvents and their limited stability. That notwithstanding in recent years there has been a surge of interest in bringing these sustainable metal reagents into the forefront of organometallics in synthesis. Showcasing the growth in utilisation of organosodium complexes within several areas of synthetic chemistry, this Minireview discusses promising new methods that have been recently reported with the goal of taming these powerful reagents. Special emphasis is placed on coordination and aggregation effects in these reagents which can impart profound changes in their solubility and reactivity. Differences in observed reactivity between more nucleophilic aryl and alkyl sodium reagents and the less nucleophilic but highly basic sodium amides are discussed along with current mechanistic understanding of their reactivities. Overall, this review aims to inspire growth in this exciting field of research to allow for the integration of organosodium complexes within common important synthetic transformations.

New Frontiers in Organosodium Chemistry as Sustainable Alternatives to Organolithium Reagents.

With their highly reactive respective C-Na and N-Na bonds, organosodium and sodium amide reagents could be viewed as obvious replacements or even superior reagents to the popular, widely utilised organolithiums. However, they have seen very limited applications in synthesis due mainly to poor solubility in common solvents and their limited stability. That notwithstanding in recent years there has been a surge of interest in bringing these sustainable metal reagents into the forefront of organometallics in synthesis. Showcasing the growth in utilisation of organosodium complexes within several areas of synthetic chemistry, this Minireview discusses promising new methods that have been recently reported with the goal of taming these powerful reagents. Special emphasis is placed on coordination and aggregation effects in these reagents which can impart profound changes in their solubility and reactivity. Differences in observed reactivity between more nucleophilic aryl and alkyl sodium reagents and the less nucleophilic but highly basic sodium amides are discussed along with current mechanistic understanding of their reactivities. Overall, this review aims to inspire growth in this exciting field of research to allow for the integration of organosodium complexes within common important synthetic transformations.

Effect of siliceous sand volume fraction on the properties of alkali-activated slag mortars

One of the critical factors affecting the performance of alkali-activated slag (AAS) is the nature and dose of alkali activator. The activator type can play a significant role during the transition from pastes to mortars or concretes. Therefore, three basic sodium activators (water glass, carbonate, and hydroxide) of the same molarity of 4M Na+ were used to prepare AAS-based mortars with different volume fractions of siliceous sand. These were compared by means of workability, mechanical strength, and long-term shrinkage under autogenous conditions. The results were compared to those obtained on pastes with similar workability. Increasing the content of the sand tended rather to decrease the mechanical properties, while greatly decreased autogenous shrinkage. Nevertheless, the most remarkable differences for different activators were observed when comparing the mortars with pastes. The transition from pastes to mortars resulted in the highest reduction in both compressive and flexural strength for sodium hydroxide. The flexural strength of the mortars with sodium water glass and sodium carbonate even increased considerably in presence of sand.

Development of structural colored TiO2 thin films by varied etching solutions

Currently, one of the most important problems is water scarcity due to increasing population and environmental factors. Humankind can overcome this problem by recycling polluted water. The structural colors obtained from photonic crystal structures draw attention with fadeless bright color, combined with low toxicity and eco-friendliness. In this study, different etching/anodizing processes were applied to obtain Fabry-Perot and Photonic Crystal Ti-TiO2 structures. Structural colors owing to the morphology of the anatase phase on the surface of the samples etched with hydrochloric, sulfuric, and hydrofluoric acid-based solutions were obtained. The structural color of the formation on the titanium surfaces is related to the Fabry-Perot structures, while variations were correlated with Photonic Crystal surface morphologies. Because the high reflectance values contributed to the structural color formation, the photocatalytic efficiency of the samples etched with acid-based solutions was found to be lower than the samples etched with basic sodium and potassium hydroxide solutions. High-efficiency structural color reactors can be obtained by shifting the reflected wavelength range from the absorption wavelength range of the pollution material.

Amorphous aluminosilicates as efficient ion exchangers for ammonium cation removal from aqueous solutions

The efficient removal of ammonium cation, one of the main causes of the eutrophication of water sources, has been achieved by using amorphous aluminosilicates as low-cost ion exchangers. The materials with a Si/Al ratio that varied from 1 to 5 were prepared by the coprecipitation method just by mixing an acidic aluminium sulphate solution with a basic sodium silicate solution, and the products were characterized by XRD, SEM and 27Al MAS NMR spectroscopy. All the amorphous solids presented a higher cation exchange capacity (CEC) than a synthetic mordenite (Si/Al = 9.5) and a natural zeolite (Si/Al = 4.6). The ammonium uptake was investigated as a function of contact time and initial ammonium concentration; additionally, the presence of Na+ and K+ as coexisting cations in the solutions was also evaluated. Langmuir and Freundlich models were applied to describe the data obtained in the ammonium exchange isotherms. The amorphous aluminosilicate with Si/Al = 3 was regenerated with a KCl aqueous solution and was reused 5 times keeping a stable removal efficiency. The reusability of the amorphous aluminosilicate combined with the superior cation exchange capacity manifests the promising use of this type of materials as ion exchangers to remove ammonium cations from wastewater.

Sodium mediated deprotonative borylation of arenes using sterically demanding B(CH2SiMe3)3: unlocking polybasic behaviour and competing lateral borane sodiation.

The deprotonative metalation of organic molecules has become a convenient route to prepare functionalised aromatic substrates. Amongst the different metallating reagents available, sodium bases have recently emerged as a more sustainable and powerful alternative to their lithium analogues. Here we report the study of the sterically demanding electrophilic trap B(CH2SiMe3)3 for the deprotonative borylation of arenes using NaTMP (TMP = 2,2,6,6-tetramethylpiperidide) in combination with tridentate Lewis donor PMDETA (PMDETA = N,N,N',N'',N''-pentamethyldiethylenetriamine). Using anisole and benzene as model substrates, unexpected polybasic behaviour has been uncovered, which enables the formal borylation of two equivalents of the relevant arene. The combination of X-ray crystallographic and NMR monitoring studies with DFT calculations has revealed that while the first B-C bond forming process takes place via a sodiation/borylation sequence to furnish [(PMDETA)NaB(Ar)(CH2SiMe3)3] species, the second borylation step is facilitated by the formation of a borata-alkene intermediate, without the need of an external base. For non-activated benzene, it has also been found that under stoichimetric conditions the lateral sodiation of B(CH2SiMe3)3 becomes a competitive reaction pathway furnishing a novel borata-alkene complex. Showing a clear alkali-metal effect, the use of the sodium base is key to access this reactivity, while the metalation/borylation of the amine donor PMDETA is observed instead when LiTMP is used.

Changing the reaction pathway in TiO2 photocatalytic dehalogenation of halogenated aromatic pollutants by surface hydroxyl regulation.

Understanding the photocatalytic reductive dehalogenation mechanism of halogenated aromatic pollutants is of great research value. However, the proton source in the photocatalytic dehalogenation process of representative halogenated aromatic pollutants by TiO2 is not clear. In this study, the TiO2 surface was modified by hydrochloric acid, sodium hydroxide, and sodium fluoride to obtain TiO2 samples with different hydroxyl groups. It was found that the hydroxyl groups on the surface of TiO2 affects the sequence of proton and electron transfer in dehalogenation. The abundance of hydroxyl groups on the surface of TiO2 can accelerate the reductive dehalogenation process of representative halogenated aromatic pollutants. The kinetic solvent isotope effect was used to study the proton-coupled electron transfer process in the reaction. It shows that the enriching of protons on TiO2 bridging oxygen (bridging hydroxyl groups) is conducive to the rapid step of protonation of the reactant, and subsequent proton and electron transfer. On the contrary, the bridging hydroxyl groups can be removed by reacting with strongly basic sodium hydroxide and sodium ions can occupy the bridging oxygen. The substitution of bridging oxygen by fluorine ions can also lead to the destruction of bridge hydroxyl groups. Significantly, the absence of bridging hydroxyl groups on titanium dioxide will lead to the dehalogenation of representative halogenated aromatic pollutants initiated by electron transfer. This study is helpful to understand dehalogenation reaction paths catalyzed by TiO2.

Recovery of Spent Liming Liquor Case study: Afrotan Tannery, Sudan

Spent liming liquor is produced from unhairing and liming processes. This study was carried out in Afrotan Tannery, by using the existing liming recovery unit in the tannery. The aim of the study is to determine and to evaluate the efficiency of the method of treatment applied in liming liquor recovery unit. The results showed that the value of pH was 12 and the values of TSS, Cl, NH4 and COD in liming liquor before treatment were 10623, 8511, 498 and 37396 mg/l, respectively. The value of pH is 11.5 and the values of TSS, Cl, NH4, COD and sulphide in liming liquor after treatment were 4321, 7796, 407, 21985 and1602mg/l, respectively. The liming liquor recovery unit receives 300 m3/day of spent liming liquor. 140 m3/day of the quantity is floated and precipitated as sludge. 60 m3/day of this sludge does not enter sludge treatment unit and directly is filled in land contaminating the soil with sulphide. 160 m3/day of the quantity is the treated spent liming liquor which is mixed with fresh makeup basic sodium sulfide and ammonium sulphate and recycled in unhairing and liming processes. The study concludes that it is important to conduct further studies to decrease COD in clear liming liquor and to send all sludge to sludge treatment unit.

Penentuan Kondisi Optimum Waktu Aging dan Temperatur Pengeringan Pada Sintesis Silika Xerogel dengan Bahan Dasar Natrium Silikat dari Silika Alam

Abstract — Silica is one kind of porous material that is suited to adsorben. In the synthesis process, silica gel can be produced using a sol-gel method based on the sodium silicate (Na2SiO3), which is prepared by an acid. The project of this research is to establish optimum conditions in aging time and gel-drying temperatures to produce a broad surface and pore size for silica xerogel. Based on the iod's absorption of variations in aging time (14, 16, 18, 20 and 24 hours) and drying temperatures (60, 70, 80, 90 and 100°C) give the most absorption to optimum conditions of aging time at 18 hours and drying temperatures of 70°C. The presence of XRD pattern leads to amorphous nature structures that dilate at one peak in 2θ = 22.545°, which indicates synthesis of silica xerogel with a basic sodium silicate obtained from natural silica was successfully made and highly pure. Keywords — Silica, Sodium Silicate, Silica xerogel

Soluble phosphate salts as setting aids for premixed calcium phosphate bone cement pastes

Recently, premixed calcium phosphate cement pastes have been proposed as biomaterials for bone tissue repair and regeneration. Use of premixed pastes saves the time and removes an extra step during a medical operation. α-Tricalcium phosphate (α-TCP) based cements set to form calcium deficient hydroxyapatite which has a moderate bioresorbtion speed. α-TCP cements require a setting aid, usually a sodium or potassium phosphate salt, to speed up the setting process. Within the current research we investigated which setting aid has significant advantage, if α-TCP is used in form of non-aqueous premixed paste. This approach offers the application of simple ingredients to produce a premixed calcium phosphate cement. The following properties of cement formulations were evaluated: cohesion, phase composition, microstructure, pH value of the liquid surrounding the cement, and compressive strength.Compositions using mixture of basic and acidic potassium phosphate salts (KH2PO4 and K2HPO4) in sufficient amounts give the best overall results (adequate cohesion and pH of the surrounding liquid, hydrolysis of starting materials within 48 h, and compressive strength of 12 ± 3 MPa). Cement prepared with basic sodium phosphate salt (Na2HPO4) as setting aid had considerably higher compressive strength 22 ± 1 MPa, but the pH of the surrounding liquid was basic (9.0).

Synthesis and Characterization of Silica Core/Multilayered Cobalt Ferrite-Silica Shell Particles for Lipase Immobilization

Multilayered core/shell particles were prepared by four-step deposition of cobalt ferrite layers and then deposition of external silica layer on the surface of silica core particles. The ferrite nanoparticles were obtained by co-precipitation of Co2+ and Fe3+ ions at pH=11 and pH=15, respectively. The agglomerated silica core/cobalt ferrite shell particles were obtained at extremely basic pH (pH=15), while at pH =11, monodispersed and non-aggregated core-shell particles were obtained. The poly(diallyldimethylammonium chloride)-functionalized silica core/ferrite shell particles were used as templates for deposition of mesoporous silica layers (obtained by neutralization of highly basic sodium silicate solution). The obtained porous multilayered core/shell particles were used as a host for covalent lipase immobilization inside the external silica layer. The initial activity of immobilized enzymes was about 13-fold lower than the native one, however, it showed good reusability and improved thermal stability compared to native ones.

The bioavailability of ingested 26Al-labelled aluminium and aluminium compounds in the rat

The fractional uptake of ingested aluminium and aluminium compounds (aluminium citrate, aluminium nitrate, aluminium chloride, aluminium sulphate, aluminium hydroxide, aluminium oxide, aluminium metal, powdered aluminium pot electrolyte, acidic sodium aluminium phosphate (SALP), basic sodium aluminium phosphate (Kasal), sodium aluminium silicate and FD&C red 40 aluminium lake) from the gastro-intestinal tract of adult female rats was measured. This was determined by comparing retained body burden of 26Al at seven days post-admistration of an i.v. injection of 26Al-labelled aluminium citrate with that retained following the gastric admistration of 26Al-labelled test compounds as either solutions or suspended solid. The calculated percentage uptake of 26Al for all the aluminium solutions was similar: aluminium citrate 0.08%, aluminium chloride 0.05%, aluminium nitrate 0.05% and aluminium sulphate 0.21%. The uptake of 26Al administered as insoluble particulates was lower: 0.03% for aluminium hydroxide; 0.02% for aluminium oxide; 0.04% for powdered pot electrolyte; 0.12% for sodium aluminium silicate; and 0.09% for FD&C red 40 aluminium lake. For aluminium metal, SALP and Kasal the amount of 26Al present in the rats was insufficient to determine uptake and was less than 0.03%. The results produced for aluminium citrate, aluminium hydroxide and aluminium sulphate are close to those published for man.

Superior Ion-exchange Property of Amorphous Aluminosilicates Prepared by a Co-precipitation Method.

The development of inexpensive inorganic ion-exchangers for the purification of environmental pollutants is a social demand. Amorphous aluminosilicates with a relatively high homogeneous Al environment are prepared by a feasible co-precipitation method, i. e., mixing an acidic aluminum sulfate solution and basic sodium silicate solution, which exhibit excellent ion-exchange selectivity for Cs+ and Sr2+ . The Kd value for Sr2+ was comparable with that of zeolite 4A. The local structures and ion-exchange behavior of the amorphous aluminosilicates are systematically investigated. The ion-exchange property of the amorphous aluminosilicates can be tuned by changing the interaction between the exchangeable cation and the amorphous aluminosilicates. Also, the amorphous aluminosilicates can adsorb bulky cations that zeolites hardly adsorb due to the limitation of the miropore size of zeolites.

Enzyme immobilization using two processing methods onto silica core-shell particles

Two methods of enzyme immobilization onto silica core-shell particles were developed. The first method involved the immobilization of Candida rugosa lipase inside a previously synthesized mesoporous silica layer (deposited at 80°C) surrounding a dense silica core. To prevent lipase leakage from the support, an outer mesoporous silica layer was deposited at 40°C around the first silica layer containing the immobilized lipase. The deposition of the second layer was performed at a relatively lower temperature, to prevent thermal inactivation of the immobilized enzyme. The internal silica layer was obtained by assembling primary silica nanoparticles generated from highly basic sodium silicate solution at 80°C on the surface of poly (diallyldimethylammonium chloride) (PDDA) functionalized silica core particles. The average shell thickness and pore size of the internal silica layer was ∼60nm and 24nm, respectively. The effect of process parameters on generation and aggregation of silica nanoparticles prepared from highly basic sodium silicate solution was also investigated. The aggregation of silica particles generated at 40°C and 80°C took place after 840s and 570 of reactions, respectively. The immobilization efficiency of lipase on the mesoporous silica monolayer was 80%. A decline of immobilized lipase activity was approximately 6 times after 10 reaction cycles due to lipase leakage from the monolayered shell. An outer mesoporous silica layer was deposited at 40°C onto the surface of previously PDDA-functionalized monolayered silica core-shell particles containing the immobilized lipase. The average thickness and pore size of outer mesoporous silica layer was ∼60nm and 17nm, respectively. The activity of lipase immobilized inside the bilayered shell was further reduced due to diffusion resistance within the outer silica layer and PDDA layer however, it was retained for the next reaction cycles.The pore size of mesoporous silica layer obtained at 80°C was insufficient to allow invertase immobilization. Thus, the second method for the immobilization of invertase was developed. It involved the preparation of the mesoporous silica layer simultaneously with invertase immobilization at 40°C. The immobilized invertase showed decreased activity, but it was not hampered by substrate inhibition, as in the case of the free enzyme, due to the location of the enzyme inside the mesoporous silica layer, where the mass transfer resistance for the substrate to the enzyme active site was present.

Ancillary Ligand and Base Influences on Nickel-Catalyzed Coupling of CO2 and Ethylene to Acrylate

The coupling of CO2 and ethylene to produce acrylates has been an area of increasing interest in recent years following a number of studies which have empirically improved catalytic turnover. Notably, the incorporation of moderately Brønsted and Lewis basic sodium phenoxide salts, as well as zinc dust, and Lewis acidic lithium salts were found to facilitate acrylate formation in batch catalysis. Despite these advances, there has been limited investigation into the effect of the catalyst ancillary ligand and phenoxide base structure on catalytic performance. Here, a collection of 1,2-bis(dialkylphosphino)benzene and related diphosphine ligands were used to show that the influence of steric environs has a marked effect on turnover. Ancillary diphosphine ligands featuring at least two smaller alkyl substituents are needed for strong activity, while the oft-used benzene annulation of the diphosphine does not appear to be determinant in achieving high turnover values. Additionally, the investigation of a collection of substituted sodium phenoxide bases suggests that a subtle balance of basicity and steric factors must be satisfied to obtain optimal catalytic performance. These trends appear to result from competitive, deleterious nucleophilic reactions between base and CO2 to produce carbonate and the need to maintain sufficient basicity and access to the metal coordination sphere to drive the endergonic CO2–ethylene coupling reaction.

Realization of Lewis Basic Sodium Anion in the NaBH3 - Cluster.

We report a Na:- →B dative bond in the NaBH3 - cluster, which was designed on the principle of minimum-energy rupture, prepared by laser vaporization, and characterized by a synergy of anion photoelectron spectroscopy and electronic structure calculations. The global minimum of NaBH3 - features a Na-B bond. Its preferred heterolytic dissociation conforms with the IUPAC definition of dative bond. The lone electron pair revealed on Na and the negative Laplacian of electron density at the bond critical point further confirm the dative nature of the Na-B bond. This study represents the first example of a Lewis adduct with an alkalide as the Lewis base.