Sodium Hydroxide Water Research Articles

Selective Thermal and Photocatalytic Decomposition of Aqueous Hydrazine to Produce H2 over Ag-Modified TiO2 Nanomaterial.

An Ag-modified TiO2 nanomaterial was prepared by a one-pot synthesis method using tetra butyl titanate, silver nitrate, and sodium hydroxide in water at 473 K for 3 h. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to determine the structure and morphology of the synthesized Ag-modified TiO2 nanomaterial. The diffuse reflectance UV-visible and photoluminescence spectroscopy results revealed that metallic Ag nanoparticles decreased the optical band gap and photoluminescence intensity of the TiO2. In addition, the Raman peak intensity and absorbance were increased after Ag modification onto TiO2. The photocatalytic efficiency of the synthesized samples was tested for decomposition of aqueous hydrazine solution under visible light irradiation. The photocatalytic efficiency of Ag-modified TiO2 nanomaterials was higher than that of bare TiO2 and Ag metal NPs due to the synergistic effect between the Ag metal and TiO2 structures. In addition, the surface plasmon resonance (SPR) electron transfer from Ag metal particles to the conduction band of TiO2 is responsible for superior activity of TiO2-Ag catalyst. The Ag-modified TiO2 nanomaterials offered a 100% H2 selectivity within 30 min of reaction time and an apparent rate constant of 0.018 min-1 with an activation energy of 34.4 kJ/mol under visible light radiation.

Synthesis of Natural Salicylic Acid as a Cosmetic Ingredient Using Green Chemistry Methods

Objective: Salicylic acid (SA) is a keratinolytic agent also used as preservative in cosmetic products. Green chemistry, known as sustainable chemistry, is the design of products and processes eliminating the use of chemicals. It is applicable throughout a chemical product's life cycle, including its design, manufacture, use, and final disposal. The aim of this study was to synthesize SA with green chemistry methods using different amounts of wintergreen oil and to optimize the relevant steps in this path. Materials and Methods: The SA was synthesized from natural wintergreen oil using green chemistry methods. First laboratory-scale synthesis was developed and 15 laboratory-scale synthesis trial patterns, using reaction temperature, wintergreen oil-sodium hydroxide molar ratio, sodium hydroxide-water weight ratio, reaction time and pH were performed. Purity was analysed with gas chromatographymass spectrometry (GC-MS) and moisture analysis was performed. Results and Conclusion: As a result of pilot production run with 1 kg, 5 kg, and three batches of 20 kg of wintergreen oil, SA was produced with a yield range of 91.06-93.92 %. The resulting SA batches had a purity of approximately 99%. This is a sufficient degree of purity for SA to be used as a raw material in cosmetics products. Filtering the SA solution using a filter press reduced crystal drying time and brought down the total production time to eight days.

Determination of Physiochemical Properties of Biosorbents Synthesized from Water Melon Rind Using Microwave Assisted Irradiation Procedure

Three biosorbents were prepared from Watermelon Rind (WMR) using microwave assisted procedure and then characterized using physiochemical techniques (pH, bulk density, volatile matter, surface area, ash content and moisture content). Physiochemical characterization of the synthesized biosorbents was done in order to evaluate their adsorption potentials. Accordingly, results obtained from the experiments conducted revealed the following trend: pH: Water Melon Rind treated with Sodium hydroxide (NaWMR) 8.5 > Water Melon Rind treated with Hydrogen peroxide (HP-WMR) 8.1 > Water Melon Rind treated with Distilled water (DWMR) 6.4 > Untreated Water Melon Rind (UWMR) 5.4, which suggest that NaWMR and HP-WMR possess suitable pH values for the uptake of cationic species within aqueous systems. Surface Area: analysis: UWMR (21.4 m2/g), DWMR (35.8 m2/g), NaWMR (40.6 m2/g) and HP-WMR (61.4 m2/g). This means that HP-WMR has a larger surface area and could be a preferred candidate for adsorption processes. The results obtained from this study suggest that chemical modification of Water Melon Rind (WMR) with either distilled water Sodium Hydroxide or Hydrogen peroxide by means of microwave irradiation enhances physiochemical properties which could boost the adsorption capacity of Water Melon Rind. Thus, the outcome shows that all the three synthesized biosorbents; DWMR, NaWMR and HP-WMR possess the characteristics of a good adsorbent. Accordingly, they can be applied to wastewater treatment process.

The microscopic diagnostic signs of some Fabaceae L. genus representatives. Message ІІ. Plant conducting system

The world plant products market is expanded rapidly and trade in them tends to grow by 15–25 % annually. The number of reports is increased proportionally about accidental contamination or deliberate, economically motivated falsification of plant raw materials. 27 % of the nearly 6.000 herbal preparations that are sold in 37 countries have contained undeclared contaminants, substitutes, or other components, according to the literature. We have conducted a plant conduction system microscopic analysis of the individual members’ genus Clover (Trifoliae L.), Fabaceae L. to identify morphoanatomical characteristics. Clover has anti-inflammatory, antiseptic, choleretic, diaphoretic, diuretic, hemostatic, expectorant, astringent properties and is used in many diseases. Aim. The finding common features and those that differ and can be used as diagnostic during studying the conducting system structure of genus Trifolium L. leaves and stems. Materials and methods. Plant material (herb) from Trifolium pratense L., T. incarnatum L., T. repens L. and T. fragiferum L. was harvested during the active flowering period – (May – June) and was dried in a well-ventilated place. Leaves and stems preparations were pre-boiled in 5 % sodium hydroxide water solution and fixed in chloral hydrate solution. Cross-sections were made with a microtome. The BIOLAM LOMO light microscope (Russia) and OLYMPUS SH-21 digital camera were used to record the data about identify the conducting apparatus of the plant’s leaf, petiole, and stem. Results. It has been examined the central vein structure of T. pratense L. and T. fragiferum L. leaves, it was determined that the conductive system is covered with a crystalline coating and there is one closed collateral bundle in the center, which is not typical for dicotyledonous plants. The petioles of T. incarnatum L., T. fragiferum L., and T. repens L. in cross-section are several different shapes. There are kidney-shaped and round. The conducting apparatus T. incarnatum L. and T. repens L. have arranged in a circle, closed and collateral. The leafstalk structure type of T. fragiferum L. is bunchles. It contradicts too the information about the structure conducting system of dicotyledonous plants. The stem’s conducting bundles are collateral and open. Conclusions. We have paid attention to the structural peculiarities of the conductive system of the central vein and petiole of objects for study: Trifolium pratense L., T. incarnatum L., T. repens L., and T. fragiferum L. when searching for differentiating features in some members of the genus Trifoliae L. in pharmacognostic analysis. The Dicotyledonae representatives are not characteristic of the closed type of conductive bundles, which we observed during microscopic examination.

Preparation and Characterization of Novel Mixed Periodic Mesoporous Organosilica Nanoparticles.

We report herein the preparation of mixed periodic mesoporous organosilica nanoparticles (E-Pn 75/25 and 90/10 PMO NPs) by sol-gel co-condensation of E-1,2-bis(triethoxysilyl)ethylene ((E)-BTSE or E) with previously synthesized disilylated tert-butyl 3,5-dialkoxybenzoates bearing either sulfide (precursor P1) or carbamate (precursor P2) functionalities in the linker. The syntheses were performed with cetyltrimethylammonium bromide (CTAB) as template in the presence of sodium hydroxide in water at 80 °C. The nanomaterials have been characterized by Transmission Electron Microscopy (TEM), nitrogen-sorption measurements (BET), Dynamic Light Scattering (DLS), zeta-potential, Thermogravimetric Analysis (TGA), FTIR, 13C CP MAS NMR and small angle X-ray diffraction (p-XRD). All the nanomaterials were obtained as mesoporous rodlike-shape nanoparticles. Remarkably, E-Pn 90/10 PMO NPs presented high specific surface areas ranging from 700 to 970 m2g−1, comparable or even higher than pure E PMO nanorods. Moreover, XRD analyses showed an organized porosity for E-P1 90/10 PMO NPs typical for a hexagonal 2D symmetry. The other materials showed a worm-like mesoporosity.

Effect of the Composition of the Medium on the Selectivity of Deactivation of Skeletal Nickel Catalyst

The effect of the composition of the catalytic system (the nature and composition of the solvent, specifically, aqueous solutions of sodium hydroxide and their mixtures with aliphatic alcohols with the alcohol concentration of 0.11 mole fractions) and additions of a catalyst poison (sodium sulfide) on the catalytic activity of skeletal nickel in the liquid-phase hydrogenation of the carbon‒carbon double bond in sodium maleate was studied. The assumption was made on the decisive role of the solvent in changing the activity of skeletal nickel in the hydrogenation reaction of sodium maleate, which is primarily associated with the redistribution of individual forms of adsorbed hydrogen. In was found that in the water‒sodium hydroxide‒monohydric alcohol solvent skeletal nickel undergoes selective deactivation at the NaOH concentration of 0.01 M, antiselective deactivation at the NaOH concentration of 0.10 M, and variable deactivation at the NaOH concentration of 1.0 M. It is shown that in some cases sodium sulfide additions exert a promoting effect on skeletal nickel in the hydrogenation of sodium maleate.

Synthesis of Transparent Aqueous ZrO2 Nanodispersion with a Controllable Crystalline Phase without Modification for a High-Refractive-Index Nanocomposite Film.

The controllable synthesis of metal oxide nanoparticles is of fundamental and technological interest. In this article, highly transparent aqueous nanodispersion of ZrO2 with controllable crystalline phase, high concentration, and long-term stability was facilely prepared without any modification via the reaction of inexpensive inorganic zirconium salt and sodium hydroxide in water under an acid surrounding, combined with hydrothermal treatment. The as-prepared transparent nanodispersion had an average particle size of 7 nm, a high stability of 18 months, and a high solid content of 35 wt %. ZrO2 nanocrystals could be readily dispersed in many solvents with high polarity including ethanol, dimethyl sulfoxide, acetic acid, ethylene glycol, and N, N-dimethylformamide, forming stable transparent nanodispersions. Furthermore, highly transparent polyvinyl alcohol/ZrO2 nanocomposite films with high refractive index were successfully prepared with a simple solution mixing route. The refractive index could be tuned from 1.528 to 1.754 (@ 589 nm) by changing the mass fraction (0-80 wt %) of ZrO2 in transparent nanocomposite films.

Hybrid Solar-Geothermal Energy Absorption Air-Conditioning System Operating with NaOH-H2O—Las Tres Vírgenes (Baja California Sur), “La Reforma” Case

Solar and geothermal energies are considered cleaner and more useful energy sources that can be used to avoid the negative environmental impacts caused by burning fossil fuels. Several works have reported air-conditioning systems that use solar energy coupled to geothermal renewable energy as a thermal source. In this study, an Absorption Air-Conditioning System (AACS) used sodium hydroxide-water (NaOH-H2O) instead of lithium bromide-water to reduce the cost. Low enthalpy geothermal heat was derived from two shallow wells, 50 and 55 m deep. These wells are of interest due to the thermal recovery (temperature vs. time) of 56.2 °C that was possible at the maximum depth, which can be used for the first stage of the process. These wells were coupled with solar energy as a geothermal energy application for direct uses such as air-conditioning systems. We studied the performance of an absorption cooling system operating with a NaOH-H2O mixture and using a parabolic trough plant coupled with a low enthalpy geothermal heat system as a hybrid heat source, as an alternative process that can help reduce operating costs and carbon dioxide emissions. The numerical heat transfer results showed the maximum convective heat transfer coefficient, as function of fluid velocity, and maximum temperature for a depth higher than 40 m. The results showed that the highest temperatures occur at low fluid velocities of less than or equal to 5.0 m/s. Under these conditions, reaching temperatures between 51.0 and 56.2 °C in the well was possible, which is required of the geothermal energy for the solar energy process. A water stream was used as the working fluid in the parabolic trough collector field. During the evaluation stage, the average experimental storage tank temperature achieved by the parabolic trough plant was 93.8 °C on October 23 and 92.9 °C on October 25, 2017. The numerical simulation used to evaluate the performance of the absorption cycle used a generator temperature of 90 °C, a condenser and absorber temperature at 35 °C, and an evaporator temperature of 10 °C. The Coefficient of Performance was calculated as 0.71 under design conditions.

Preparation of silver nanocolloidal solution by cavitation bubble plasma

A silver nanocolloidal solution was prepared by a cavitation bubble plasma with a pair of silver rod electrodes in a sodium hydroxide water solution with the initial pH = 11.0. The cavitation bubble plasma was generated by the bipolar high voltage pulses of the repetition rate 200 kHz and the pulse width 0.8 μs in the sodium hydroxide water solution in which many cavitation bubbles produced by a high-speed rotor were feeding. The UV–Vis absorption spectra of the silver nanocolloidal solution exhibited a characteristic peak around 400 nm in wavelength. The silver nanocolloidal solution of 250 mL including silver nanoparticles of median diameter 1.3 nm and concentration 4 ppm was prepared at the processing time 1 min. The particle size in the solution increased with increasing the processing time and grew to 14.6 nm in median diameter at the processing time 20 min. The concentration of particles also increased with increasing the processing time. A TEM image of silver nanoparticles revealed that the particles were spherical crystalline.

Thermodynamic analysis of a novel sodium hydroxide-water solution absorption refrigeration, heating and power system for low-temperature heat sources

A novel sodium hydroxide-water solution absorption refrigeration, heating and organic Rankine cycle power system is proposed for low-temperature heat source utilization. The sodium hydroxide-water solution absorption refrigeration is employed as top cycle which directly absorbs heat from low-temperature heat source. While R218 organic Rankine cycle and heating subsystem are adopted to produce power and heating as designed in bottom cycles. Under the considered condition, model results indicate that refrigeration, heating and electricity efficiency are 0.8244, 0.4019 and 0.03437 with the capacity of 945.2, 460.8 and 39.41 kW, respectively. Energy and exergy efficiency of refrigeration, heating and electricity are also theoretically analyzed with various condensation temperature, evaporation temperature, turbine inlet pressure, split ratio and mass fraction of rich sodium hydroxide solution. Sensitivity of parameters to system performance is also analyzed and results indicate that energy and exergy efficiency are remarkably influenced by operating parameters. A comparison between the proposed system and three independent electrical refrigeration, heating and power systems shows that the proposed system has superior performance and the maximum primary energy saving ratio can reach approximately 0.4889. In conclusion, with the multi-productions of refrigeration, heating and electricity, the proposed polygeneration system provides a more rational and effective energy utilization from a single low temperature heat source at suitable level.

Validated HPAEC-PAD Method for the Determination of Fully Deacetylated Chitooligosaccharides.

An efficient and sensitive analytical method based on high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was established for the simultaneous separation and determination of glucosamine (GlcN)1 and chitooligosaccharides (COS) ranging from (GlcN)2 to (GlcN)6 without prior derivatization. Detection limits were 0.003 to 0.016 mg/L (corresponding to 0.4–0.6 pmol), and the linear range was 0.2 to 10 mg/L. The optimized analysis was carried out on a CarboPac-PA100 analytical column (4 × 250 mm) using isocratic elution with 0.2 M aqueous sodium hydroxide-water mixture (10:90, v/v) as the mobile phase at a 0.4 mL/min flow rate. Regression equations revealed a good linear relationship (R2 = 0.9979–0.9995, n = 7) within the test ranges. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated HPAEC-PAD method was readily applied for the quantification of (GlcN)1–6 in a commercial COS technical concentrate. The established method was also used to monitor the acid hydrolysis of a COS technical concentrate to ensure optimization of reaction conditions and minimization of (GlcN)1 degradation.

Decontamination of VX from Silicone: Characterization of Multicomponent Diffusion Effects

A continuum model of the transport and reaction processes occurring during decontamination of the chemical warfare agent (CWA) [2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX) absorbed in a silicone elastomer using solutions of sodium hydroxide in water, methanol, and mixtures thereof is presented. This model is based on the Maxwell-Stefan formulation of multicomponent diffusion along with the Flory-Huggins model of thermodynamic equilibrium in the polymer. It was found that, as methanol from the decontaminant absorbs into the silicone, the diffusivity of VX increases, accelerating its flux from the polymer phase to the decontaminant liquid phase. This composition dependence of the diffusivity was accurately described by the Vignes equation. Although the decontamination kinetics were slower for the methanol-based decontaminant in a well-stirred liquid-phase reactor, the overall performance was superior compared to the aqueous-based decontaminant due to the enhanced extraction rate from the polymer. These findings highlight the need to consider extraction dynamics on equal footing with reaction kinetics when formulating decontaminants intended for use on absorbing polymer materials.

Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60mJ/cm2 was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

О необходимости стандартизации веществ для обеззараживания воды (на примере гипохлорита натрия)

Results of a study in the sphere of standardization of technical requirements to substances to be used for water disinfection have been presented. Th e work has been carried out with sodium hypochlorite (NaOCl),one of the most widely used in water treatment substances, as an example. Comparison of technical requirements set for the current type of NaOCl by the acting standard of 1976 GOST 11086-76 “Sodium hypochlorite. Engineering specifi cations” with the corresponding European standard of 2013 EN 901:2013 has been made. It has been demonstrated that the most essential diff erences in the requirements to the substance concerns its composition, particularly in part of limitations for high-toxic elements content. Th e necessity of these limitations that are not included in GOST 11086-76 is caused by the fact that these elements can be included into the NaOCl composition and create inadmissible risks at the stage of its application, for instance, in the process of drinking water disinfection. Th e conclusion has been made that the said standard should be expanded with inclusion of the list of elements of NaOCl to be controlled. Th ey should be limited by the suffi cient safety level while thorough analysis of the output product composition is to be secured. Th us, Engineering Committee on Standardization-409 in the sphere of environmental protection has decided on revision of technical requirements set be GOST 11086-76. At that, it is assumed that the warranty of these requirements fulfi llment is the industry’s rejection of NaOCl synthesis methods by chlorination of sodium hydroxide water solutions and transition to up-to-date electro/chemical methods with the best available techniques use. Th e supposed change of the NaOCl composition should provide its competitiveness not only at the Russian but also at the world market but this would require amendments of GOST11086-76. Th e necessary changes in the standard comprise the obsolete requirements to package, marking, transporting, and storage of the product. It is supposed to this purpose to amend the new standard with rules used by the International System of Hazard Classifi cation and Chemical Production Marking, as well as with transporting regulations acting at the international level.

A photochemical method for in vitro evaluation of fluid flow in human dentine

ObjectiveTo evaluate the flow dynamics of dentine fluid using a chemiluminescence method in vitro. Materials and methodsHorizontally sliced coronal dentine specimens with thicknesses of 1.4, 1.6, 1.8, and 2.0mm (n=10 each) were prepared from extracted human third molars. After cleaning with EDTA, a mounted specimen was clamped between 2 acrylic chambers attached to both the occlusal and pulpal sides. The occlusal chamber, which was closed with a glass coverslip, was filled with a chemiluminescent solution (0.02% luminol and 1% sodium hydroxide in water). A trigger solution of 1% hydrogen peroxide and 1% potassium ferricyanide was injected into the pulpal chamber at a constant pressure of 2.5kPa, and allowed to immediately flow into the patent dentinal tubules. Four consecutive measurements (T1–T4) were performed on each sample by recording the emission of chemiluminescence with a photodetector. The relationship between the crossing time of the liquid through the slice and dentine thickness was examined. ResultsAn apparent time delay was detected between the starting points of the trigger solution run and photochemical emission at T1. Dt (Dt, s) values of each thickness group were 13.6±4.25 for 1.4mm, 18.1±2.38 for 1.6mm, 28.0±2.46 for 1.8mm, and 39.2±8.61 for 2.0mm, respectively. Dt significantly decreased as dentine became thinner towards the pulp chamber (P<0.001). ConclusionsThe velocity of fluid flow increased both with increasing dentine depth or reduction of remaining dentine thickness.

Synthesis and antibacterial activity of some 3-(5-aryl-4H-pyrazol-3-yl) anthracen-10(9H)-ones

A series of 3-(5-aryl-4H-pyrazol-3-yl)anthracen-10(9H)-ones were synthesized from anthracen-10(9H)-one (1) and studied for their in vitro antibacterial activity. Anthracen- 10(9H)-one after Friedel crafts acetylation with acetyl chloride yielded 3-acetylanthracen- 10(9H)-one (2) which on further reaction with substituted aromatic aldehydes in the presence of catalytic amount of sodium hydroxide in water and ethanol furnished the corresponding 3-(3-arylacryloyl)anthracen-10(9H)-ones (3a-g) as intermediate compounds, which on further reaction with hydrazine hydrate in absolute ethanol formed the title compounds 3-(5-aryl-4H-pyrazol-3-yl)anthracen-10(9H)-ones (4a-g). These compounds were characterized by elemental analysis, IR, Mass and 1H-NMR spectral data. All the compounds were evaluated for their in vitro antibacterial activity against two gram positive strains (Bacillus subtilis and Staphylococcus aureus) and two gram negative strains (Escherichia coli and Pseudomonas aeruginosa) taking ciprofloxacin as a standard drug. Some of the compounds showed significant antibacterial activity.

Synthesis and biological screening of pyrazole moiety containing analogs of podophyllotoxin

The pyrazole moiety containing analogs of podophyllotoxin as potential antimitotic agents were synthesized in five step reactions via chalcone route. The first step is the synthesis of chalcone (2a–d) by the reaction of substituted acetophenones with p-tolualdehyde in the presence of sodium hydroxide in water–ethanol mixture. The cyclopropyl ketones (3a–d) were prepared by the reaction of chalcones (2a–d) with trimethylsulfoxonium iodide (TMSOI) in dry DMSO. The key intermediate tetralones (4a–d) were prepared by the intramolecular cyclization reaction of cyclopropyl ketones (3a–d) in the presence of anhyd. stannic chloride and acetic anhydride in dry dichloromethane. These compounds (4a–d) on formylation give substituted hydroxylmethylene tetralones (5a–d). Further, pyrazole moiety containing analogs of podophyllotoxin (6a–d) were synthesized in high yields by the condensation of hydroxylmethylene tetralones (5a–d) with hydrazine hydrate in absolute ethanol. The structures of the synthesized compounds were confirmed by spectral and elemental analysis data. The synthesized compounds were also screened for their antimitotic activity. It is noteworthy that compounds 6d possessed excellent antimitotic activity, 6b and 6c showed considerable activity, and remaining 6a possessed least activity. Compound 6d was immense to show high antibacterial and antifungal activity against all bacterial and fungal strains compared with standard chloramphenicol and nystatin, respectively.

Simulations of dissociation constants in low pressure supercritical water

This article reports molecular dynamics simulations of the dissociation of hydrochloric acid and sodium hydroxide in water from ambient to supercritical temperatures at a fixed pressure of 250 atm. Corrosion of reaction vessels is known to be a serious problem of supercritical water, and acid/base dissociation can be a significant contributing factor to this. The SPC/e model was used in conjunction with solute models determined from density functional calculations and OPLSAA Lennard–Jones parameters. Radial distribution functions were calculated, and these show a significant increase in solute–solvent ordering upon forming the product ions at all temperatures. For both dissociations, rapidly decreasing entropy of reaction was found to be the controlling thermodynamic factor, and this is thought to arise due to the ions produced from dissociation maintaining a relatively high density and ordered solvation shell compared to the reactants. The change in entropy of reaction reaches a minimum at the critical temperature. The values of pKa and pKb were calculated and both increased with temperature, in qualitative agreement with other work, until a maximum value at 748 K, after which there was a slight decrease.

A Validated method for determination of Metabisulfite content in Cetrizine Dihydrochloride and Ambroxol Hydrochloride 5+30mg/5mL syrup by Ion exchange chromatography

A commercial, particular and strong Ion Chromatography method was developed for the quantitative determination of metabisulfite content in Cetrizine Ambroxol syrup. The method was developed using Ion pac AS11HC Column, 250 X 4.6mm X 5.0 m column with mobile phase containing 18mM sodium hydroxide in water. The eluted compounds were monitored using conductivity detector. The developed method was validated as per ICH guidelines with respect to limit of detection(LOD), limit of quantification(LOQ), exactness, reproducibility, ruggedness and robustness. The LOD, LOQ values of metabisulfite were 0.3PPM and 1.0PPM respectively.

Metal-Free Synthesis of Aryl Ethers in Water

The first arylation of allylic and benzylic alcohols with diaryliodonium salts is reported. The reaction yields alkyl aryl ethers under mild and metal-free conditions. Phenols are arylated to diaryl ethers in good to excellent yields. The reaction employs diaryliodonium salts and sodium hydroxide in water at low temperature, and excess amounts of the coupling partners are avoided.