Sodium Phenoxide Research Articles

Aqueous anion binder for phenolate and nitro substituted phenolates through second-sphere coordination network

A series of four cobalt(III) complexes, [Co(Hbig)3]1.5Cl3.5(Ph).2H2O (1), [Co(Hbig)3] (PNP)3.H2O (2), [Co(Hbig)3](DNP)3.H2O (3) and [Co(Hbig)3](TNP)3·4H2O (4) have been synthesized by reacting [Co(Hbig)3]Cl3.H2O (Hbig: biguanide) with sodium phenolates (Ph: pheonlate, PNP: 4-nitrophenolate, DNP: 2,4-dinitrophenolate or TNP: 2,4,6-trinitrophenolate) in 1:3 molar ratio in aqueous medium. All the complexes were initially characterized by physiochemical and spectroscopic (UV–Visible, IR and NMR) studies. Anion binding affinity of complex cation for anions has been studies in aqueous medium using UV–Visible spectroscopic titrations and found log β values for anions. The single crystal X-ray structures of complex 3 and 4 were also determined and stacking of layers has been observed in both the structures. These stacking layers contains layers of [Co(Hbig)3]3+, nitro-phenolate (DNP or TNP) and water molecules along b-axis. These layers connected with one another by numerous intermolecular N-H…O hydrogen bonds leads to formation of second-sphere coordination network. Further, all the complexes and their respective reactants have been tested for antimicrobial activities against strain of Gram negative (P. aeruginosa, E. coli, K. pneumoniae, S. typhi), strain of Gram positive bacteria (B. subtilis, S. epidermidis) and antifungal against C. herbarum, A. alternata and F. oxysporum.

Clickable bisreactive small gold nanoclusters for preparing multifunctionalized nanomaterials: application to photouncaging of an anticancer molecule.

In this study, we successfully synthesized a small-sized gold nanocluster (2 nm) coated with homogeneous tripeptides bearing azido and amino groups that enable facile multifunctionalizations. Using sodium phenoxide to reduce tetrachloroauric(iii) acid in the presence of the cysteine-containing tripeptide, we efficiently prepared the gold nanoclusters without damaging the azido group. We then utilized this clickable bisreactive nanocluster as a versatile platform for synthesizing multifunctionalized gold nanomaterials. The resulting nanoclusters were conjugated with an anticancer compound connected to an indolizine moiety for photoinduced uncaging, a photodynamic therapy agent acting as a photosensitizer for uncaging, and a cyclic RGD peptide. The cytotoxicity of the multifunctionalized gold nanoclusters was demonstrated through red light irradiation of human lung cancer-derived A549 cells treated with the synthesized nanomaterials. The significant cytotoxicity exhibited by the cells underscores the potential utility of this method in advanced cancer therapies.

Molecular dynamics simulation of the Kolbe-Schmitt carboxylation mechanism of sodium phenoxide

Although we had some understanding of the Kolbe-Schmitt reaction as early as the 21th century, it is surprising that the reaction did not receive sufficient attention through theoretical approaches. The mechanistic underpinnings of the industrially pivotal Kolbe-Schmitt reaction have been the focus of intensive experimental and computational scrutiny. In the present study, we scrutinized the carboxylation of sodium phenoxide with carbon dioxide via density functional theory (DFT) based molecular modeling at the hybrid B3LYP level. Our simulations unveiled that the reaction transpires through three discrete transition states and three discrete intermediates. The last step of the Kolbe-Schmitt reaction is the rate-determining step, as it requires the highest activation energy, which consistent with the experimental results. This concluding step of the Kolbe-Schmitt reaction demands the most substantial activation energy and thus limits the overall rate. This theoretical interrogation has furnished invaluable discernment into the intricacies of the Kolbe-Schmitt mechanism and provides strategic direction for deeper comprehension and optimization of this profoundly applicable carboxylation protocol.

Catalytic hydrogenation of phenoxide at room temperature using ultrafine Ru–B amorphous alloy

Sodium phenoxide is considered as one of the potentially promising hydrogen storage materials due to its high hydrogen capacity and enhanced thermodynamic properties. However, efficient catalysts are needed to overcome kinetic barriers of the hydrogenation and dehydrogenation processes. In the present work, an ultrafine amorphous Ru–B alloy catalyst was synthesized by a solid-phase ball milling of RuCl3 with NaBH4 and subsequently tested for the hydrogenation of sodium phenoxide in an aqueous solution at room temperature. The conversion of phenoxide is significantly improved by 48.9 % on the Ru3.9B alloy catalyst compared with pristine Ru nanoparticles. Kinetic studies revealed that the hydrogenation of sodium phenoxide is of first-order with respect to H2 pressure and zero-order to the concentration of sodium phenoxide over the Ru3.9B catalyst. Characterizations showed that the electronic structure of Ru is well modulated by B, leading to an electron-rich state of Ru. The highly active catalysis may be due to the fine dispersion, amorphous state, and electron-rich state of Ru in the ultrafine alloy.

The Preparation of Electrolyte Hydrogels with the Water Solubilization of Polybenzoxazine.

Polybenzoxazine (PBZ) exhibits excellent heat resistance, and PBZ derivatives have been designed and synthesized to achieve high performance. However, the application range of PBZ is limited by the strong interactions between molecular chains and its low solubility in organic solvents, thereby limiting its processability. This study focused on the benzoxazine structure as the molecular backbone of new hydrogel materials that can be applied as electrolyte materials and prepared functional gel materials. Here, we prepared hydrogels by water-solubilizing PBZ derivatives, which typically exhibit low solubility in organic solvents. Although studies on the hydrophilization of PBZ and its complexation with hydrophilic polymers have been conducted, no studies have been performed on the hydrogelation of PBZ. First, the phenol in the organic solvent-insoluble PBZ thin film obtained after the thermal ring-opening polymerization of the monomer was transformed into sodium phenoxide by immersion in a NaOH aqueous solution to water-solubilize it and obtain a hydrogel thin film. Although the hydrogel thin film exhibited low mechanical strength, a free-standing hydrogel film with improved strength was obtained through the double network gelation method with an acrylamide monomer system. The physical properties of the polymer composite hydrogel thin film were evaluated. The ionic conductivity of the hydrogel thin films was in the order of 10-4 S cm-1, indicating the potential of PBZ as an electrolyte hydrogel material. However, improving its ionic conductivity will be undertaken in future studies.

Thermal Behavior and Decomposition Pathway for Nitrophenols and Sodium Nitrophenolates

Nitrophenols and corresponding sodium nitrophenolates are the main side products in the production of mononitrobenzene (MNB). These side products are hazardous due to their thermal instability nature. In this article, the thermal decomposition behaviors of nitrophenols and sodium nitrophenolates were first characterized by differential scanning calorimeter and accelerating rate calorimetry techniques. Then, the influence of phenol and sodium phenolate on the thermal decomposition of MNB was studied to clarify the effect of phenolic hydroxyl groups on the thermal stability of nitrophenols. It was found that compared to nitrophenols, the exothermic peaks of sodium nitrophenolates were more intense and presented strongly autocatalytic features. Sodium phenolate could significantly decrease the decomposition temperature of MNB. Aniline was detected as the unique product in the decomposition processes of pure MNB and MNB/sodium phenolate mixtures, and the nitrosobenzene was verified as the intermediate product. It was experimentally proven that sodium phenolate could catalyze the decomposition of nitrosobenzene (the decomposition intermediate of MNB). The violent decomposition of sodium nitrophenols was caused by the intermolecular catalysis effect of phenoxy groups.

Investigation on the Formation of Rare-Earth Metal Phenoxides via Metathesis

A number of alkali organometallic complexes with suitable thermodynamic properties and high capacity for hydrogen storage have been synthesized; however, few transition metal–organic complexes have been reported for hydrogen storage. Moreover, the synthetic processes of these transition metal–organic complexes via metathesis were not well characterized previously, leading to a lack of understanding of the metathesis reaction. In the present study, yttrium phenoxide and lanthanum phenoxide were synthesized via metathesis of sodium phenoxide with YCl3 and LaCl3, respectively. Quasi in situ NMR, UV-vis, and theoretical calculations were employed to characterize the synthetic processes and the final products. It is revealed that the electron densities of phenoxides in rare-earth phenoxides are lower than in sodium phenoxide due to the stronger Lewis acidity of Y3+ and La3+. The synthetic process may follow a pathway of stepwise formation of dichloride, monochloride, and chloride-free species. Significant decreases in K-band and R-band absorption were observed in UV-vis, which may be due to the weakened conjugation effect between O and the aromatic ring after rare-earth metal substitution. Two molecular structures, i.e., planar and nonplanar, are identified by theoretical calculations for each rare-earth phenoxide. Since these two structures have very close single-point energies, they may coexist in the materials.

Realizing room temperature catalytic hydrogenation of sodium phenoxide by Ru/TiO2 for hydrogen storage.

Sodium phenoxide is a potentially promising hydrogen storage material due to its high hydrogen capacity and enhanced thermodynamic properties. Nevertheless, efficient catalysts are still lacking due to the high kinetic barrier for the reversible hydrogen uptake and release of sodium phenoxide. In the current work, a comparative study on the catalytic hydrogenation of sodium phenoxide was conducted. To our delight, a simple yet effective ruthenium-based catalyst was identified to respond aggressively to hydrogen in the solid-state hydrogenation of sodium phenoxide even at room temperature. The activity was enhanced by 6 fold with the as-synthesized 5.0% Ru/TiO2 catalyst as compared to that with commercial 5.0% Ru/Al2O3, respectively, under the same conditions.

Проблеми знефенолювання та підвищення якості вбирної фракції кам’яновугільної смоли (огляд).

PROBLEMS OF DE-PHENOLIZATION AND IMPROVEMENT OF THE QUALITY OF THE ABSORBING FRACTION (REVIEW) © A.L. Bannikov, post graduate student (National Technical University «Kharkiv Polytechnic Institute», 2 Kyrpychova Str., Kharkiv, 61002, Ukraine), O.L. Borysenko, PhD in Technіcal Sciences (State Enterprise "Ukrainian State Scientific Research Institute of Coal Chemistry (UKHIN), 7 Vesnina str., Kharkiv, 61023, Ukraine) It is shown that improving the quality of absorbent oil is now becoming an important economic task due to the need to purchase an imported absorbent of benzene hydrocarbons from coke oven gas. The need for economical consumption of fresh oil to replenish the circulation cycle determines the main requirement for the quality of the fresh absorbent. The state of the equipment and the capabilities of the technological regime of benzene departments (increased absorption temperature, insufficient heating before distillation, watering of the absorber as a result of frequent shutdowns, etc.) make it necessary to look for an oil that would provide low specific consumption in this situation. The issue of dephenolization of the wash oil fraction remains controversial, and arguments for and against de-phenolization are presented. It is shown that the de-phenolization stage with the existing sodium phenolate processing cycle cannot function in the current conditions. Stricter requirements for the management of intermediates and waste make it necessary to switch to an alternative method. The rejection of alkaline extraction of phenolics has led to the development of new separation methods for purification of coal tar distillation fractions. In particular, the wash oil fraction is still the subject of research in order to extract various individual products and groups of substances from it with new types of extractants. Data on recent studies of phenol extraction from coal fractions using completely new materials are presented. It is concluded that there are currently no new proposals ready for industrial implementation. For the functioning of fractional de-phenolization at Ukrainian enterprises, it is necessary to develop a new method with an acceptable level of processing, and extraction de-phenolization seems to be the most promising. Keywords: coal tar fractions, phenols, specific consumption, de-phenolization, extraction, ionic liquids.. Corresponding author: Bannikov Artem L., e-mail: artiksmartik@gmail.com

Selective O-alkylation of Phenol Using Dimethyl Ether

Anisole is a straw-colored aromatic compound mainly used in making solvents, flavoring agents, perfumes, fuel additives, and in the synthesis industries. Anisole, also known as methoxybenzene, is synthesized from sodium phenoxide or phenol using various methylating agents. The use of dimethyl ether (DME) as an alkylating agent is seldom reported in the literature. Herein, we have synthesized anisole through the O-alkylation process of phenol and DME to obtain zero discharge from this process. The thermodynamic equilibrium for the reaction of phenol and DME is simulated by using Aspen HYSYS (Hyprotech and Systems). The O-alkylation of phenol has been investigated using phosphotungstic acid (PTA) over γ-Al2O3 with appropriate acidity. Active metal loadings of various percentages were studied and the conversion was optimized at 46.57% with a selectivity of 88.22% at a temperature of 280 °C. The liquid products from the continuously stirred reactor were analyzed with liquid G.C. and the conversion and selectivity were calculated. A comparison of the O-alkylation and C-alkylation of phenol at different temperatures, reactant ratios, residence times, and recyclability was explored, as well as the impact of these factors on the yield of the desired anisole. The catalyst was characterized by XRD, BET, HR-TEM, FE-SEM, elemental mapping, XPS, and DRIFT studies.

Solid catalyst based on sodium hydroxide coated a hydrophobic layer for the synthesis of 4,4′-Bis (2,6-di-tert-butylphenol)

An efficient catalyst based on solid NaOH coated a hydrophobic layer was developed in this study for the synthesis of 4,4′-bis(2,6-di-tert-butylphenol) which is one of the most commonly suggested antioxidants for polymer, fuel, and lubricant stabilization. The hydrophobic coating consists of sodium phenolate and titanate, in which sodium titanate plays a role as a skeleton framework partially covering the solid NaOH surface, enhancing its mechanical durability, while sodium phenolate fills accessible surface areas and forms catalytically active sites. The chemical properties and morphological characterizations of the catalyst were characterized using SEM-EDS, TEM, FT-IR, TLC, HPLC. It has been demonstrated that the studied catalyst was highly active and extremely stable for the first stage of 4,4′-bis(2,6-di-tert-butylphenol) synthesis. Detailed analysis of kinetic regularities for this stage showed that the reaction rate was directly proportional to the first power of catalyst amount and starting material concentration as well as to the three-half power of the oxygen concentration. Additionally, the rate law expression of this stage was established and its apparent activation energy was also determined to be approximately 38.40 kJ/mol.

New methodology for separating lignin fractions: GPC on a preparative scale with stationary phase of hydrogel derived from cellulose acetate

In this paper a new stationary phase was studied, a hydrogel derived from cellulose acetate (DS 2.5) and ethylenediaminetetraacetic dianhydride (HEDTA) was used in gel permeation chromatography (GPC) on a preparative scale for elution of acetosolv lignin samples. Initially, tests were performed to verify the potential of HEDTA as a stationary phase for separation of lignin fragments and sugars, using sodium phenolate to simulate lignin, and glucose, simulating the sugars. Results have shown that more than 90 % of the two compounds were separated. Then, HEDTA was used to elute samples of acetosolv lignin extracted from sugarcane bagasse. The separation happened according to its hydrodynamic volume, where the fraction 1 (F1) with the highest average molar mass (1026 g.mol−1) showed shorter retention time. While fraction 11 (F11) had a longer retention time as expected, because F11 had lower average molar mass (740 g.mol−1). The GPC chromatograms and Fourier transform infrared spectroscopy (FTIR) spectra of the first fractions did not show curves or bands, characteristic for phenol derivatives. So, it became evident that the sample was fractioned. This work shows the synthesis of a new stationary phase for GPC with low-cost raw material, a simple procedure and derived from cellulose, a renewable resource.

Recycling Phenolic Wastewater from Phenol-Formaldehyde Resin Production

The sorption Phenolic wastewater is a kind of hazardous waste due to the presence of free phenol which is a highly toxic organic compound. Described in the literature and implemented, technology solutions for dephenolization are commonly based on thermal destruction. However, thermal treatment technologies have a range of disadvantages and the main ones of them are the losing of phenol and formaldehyde, which are valuable chemical raw materials and changing the balance of atmospheric oxygen and carbon dioxide. At the same time, owing to bonding properties, phenol and formaldehyde are used as polymer binders for manufacturing composite materials gradually replacing commercial synthetic resins. The paper presents results of the investigation related to developing a resource-saving technology for the recovery of phenol and formaldehyde from industrial phenolic wastewater by obtaining composite construction material and sodium phenolate. Sawdust and wastes from textolite manufacturing and processing were used as fillers and modifiers in a composite mixture. The presented technological process has been developed on the base of recycling using combined technologies through inter-industrial collaboration. This approach makes it possible to obtain high-quality recycled products from technogenic raw materials (degree of phenol conversion was 0.995) and to carry out complete dephenolization of the wastewater (residual phenol concentration was 2⋅10−2 mg/l), which can be used in the wastewater reuse system for the main chemical manufacturing.

Manganese/NaOPh co-catalyzed C2-selective C–H conjugate addition of indoles to α,β-unsaturated carbonyls

A manganese/NaOPh co-catalyzed C2-selective C–H conjugate addition of indoles to α,β-unsaturated carbonyls has been developed. The reaction features very high atom economy in which no stoichiometric reagents/additives were employed. The crucial role of sodium phenolate (NaOPh) as a synergetic catalyst was revealed in the reaction screening process and mechanistic experiments.

Numerical simulation of a novel fluidized bed for gas-solid non-catalytic reactions (NRFB)

This study proposed a novel fluidized bed (NRFB) to realize gas-solid non-catalytic continuous reaction. Gas and solid flowed in reverse direction in NRFB, achieving high-efficiency contact between particles and gas to form particles. The discrete phase model was used to simulate the gas-solid two-phase flow in NRFB. Basis on an optimum operating gas velocity, the characteristics of the gas-solid two-phase flow field and sodium phenolate carboxylation in NRFB were analyzed. The equal-area torus method was proposed to explore the radial particle distribution. The results showed that the gas in NRFB could be in full contact with solid particles. The introduction of the grid trays could significantly improve radial distribution and increase the residence time of sodium phenolate particles in the dense phase section, thereby improving the reaction efficiency. The simulation results can provide guidance for the determination of the operation parameters in pilot and industrial production of gas-solid non-catalytic reactions.

A novel electrochemically switched ion exchange system for phenol recovery and regeneration of NaOH from sodium phenolate wastewater

An electrochemically switched ion exchange (ESIX) system was proposed as a novel electrochemical method for the treatment of high concentration phenolic sodium salty wastewater, in which a ferric ferricyanide (FeHCF) coated electrode with rigid open framework can control the insertion/extraction of sodium (Na+) ions by switching the redox state of FeHCF. It is found that this ESIX system can not only remove the phenol and desalinate the phenol-containing wastewater simultaneously, but also regenerate the FeHCF coated electrode and produce sodium hydroxide (NaOH). In the series operation, more than 79% of phenol could be removed with energy consumption of 9.677 × 10−3 kWh mol−1, and meanwhile NaOH solution with a pH of 12.84 was generated with energy consumption of 2.083 × 10−3 kWh mol−1 during the recovery process of Na+ ions. It is expected that such an ESIX system can be applied for the treatment of phenol-containing high salinity wastewater.

Base Promoted Intumescence of Phenols.

The intumescent process of sodium (substituted) phenolates has been studied. The generation of hydrogen radical via a homolytic cleavage of the Ar–H bond and the subsequent hydroarylation of phenolates to cyclohexadienes along with cyclization and elimination reactions of cyclohexadienes are critical steps in the base promoted intumescence of phenols. The substituents show great influence on the intumescence of phenolates. Phenolates substituted with a weak electron donating group enable intumescence while those with an electron withdrawing group or strong electron donating group suppresses intumescence. This distinction can be justified by both electronic and steric effects of substituents on the generation of hydrogen radical and the degree of hydroarylation.

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.

Anionic Polymerization of β-Butyrolactone Initiated with Sodium Phenoxides. The Effect of the Initiator Basicity/Nucleophilicity on the ROP Mechanism.

It was shown that selected sodium phenoxide derivatives with different basicity and nucleophilicity, such as sodium p-nitrophenoxide, p-chlorophenoxide, 1-napthoxide, phenoxide and p-methoxyphenoxide, are effective initiators in anionic ring-opening polymerization (AROP) of β-butyrolactone in mild conditions. It was found that phenoxides as initiators in anionic ring-opening polymerization of β-butyrolactone behave as strong nucleophiles, or weak nucleophiles, as well as Brønsted bases. The resulting polyesters possessing hydroxy, phenoxy and crotonate initial groups are formed respectively by the attack of phenoxide anion at (i) C2 followed by an elimination reaction with hydroxide formation, (ii) C4 and (iii) abstraction of acidic proton at C3. The obtained poly(3-hydroxybutyrate) possesses carboxylate growing species. The ratio of the observed initial groups strongly depends on the basicity and nucleophilicity of the sodium phenoxide derivative used as initiator. The proposed mechanism of this polymerization describes the reactions leading to formation of observed end groups. Moreover, the possibility of formation of a crotonate group during the propagation step of this polymerization is also discussed.

On the Origin of Alkali-Catalyzed Aromatization of Phenols.

To gain an insight of the chemistry in the alkali-promoted aromatization of oxygen-containing heavily aromatic polymers or biomass; thermal degradations of sodium phenolates with different substituents have been investigated. The -ONa group strongly destabilizes the phenolates. The thermal stability of phenolates is largely in parallel with bond strengths of Ar substituents. De-substituents and the removal of aromatic hydrogens are dominant reactions in the main degradation step. CO is formed only at a very late stage. This degradation pattern is completely different from that of phenol. To account for this distinctive decomposition; a mechanism involving an unprecedented formation of an aromatic carbon radical anion generated from the homolytic cleavage of Ar substituent (or Ar–H) in keto forms has been proposed. The homolytic cleavage of Ar substituent (or Ar–H) is facilitated by the strong electron-donating ability of the oxygen anion. A set of free-radical reactions involved in the alkali-catalyzed aromatization have been established.