Na2CO3 Aqueous Solution Research Articles

Synthesis of 4-ethyl-5-ethylimino-[1,2,4]-dithiazolidin-3-trithione through ethyl-(4-ethyl-5-thioxo-[1,2,4]-dithiazolidin-3-ylidene)ammonium oxopentachlorotungstate(VI) hydrolysis and the dimroth rearrangement in it on heating

We demonstrate that the previously synthesized product of ethyl isothiocyanate insertion into tungsten hexachloride, WCl5{N(Et)C(S)N(Et)C(S)Cl}, whose partial hydrolysis yields {N(Et)C(S)-S-S-C=NH(Et)}[WOCl5] (I), can be used as a source of biologically active heterocyclic compounds. 1H and 13C NMR and gas chromatography-mass spectrometry data show that reaction of I with a saturated aqueous Na2CO3 solution yields a number of thiazolidine heterocycles, mostly 4-ethyl-5-ethylimino-[1,2,4]-dithiazolidin-3-trithione. The thermal Dimroth rearrangement leads to the formation of 2,4-diethyl-[1,2,4]-dithiazolidin-3,5-dithione and the products of partial hydrolysis of both heterocycles: 4-ethyl-5-ethylimino-[1,2,4]-dithiazolidin-3-on and 2,4-diethyl-3-thioxo-[1,2,4]-dithiazolidin-5-on.

Preparation and Characterization of CaCO3/High Density Polyethylene Composites with Various Shapes and Size of CaCO3

Abstract Calcium carbonate (CaCO3) with various shapes and size was prepared using CaCl2 and Na2CO3 aqueous solutions containing various additives. High density polyethylene (HDPE)/4 wt% CaCO3 composites were prepared using a Haake Rotational Rheometer. The effects of the CaCO3 particle shapes and size on the thermal and mechanical properties were investigated and characterized by differential scanning calorimetry (DSC) and universal testing machine. The results show the addition of CaCO3 to HDPE can increase the crystallization and decrease the melting temperature and crystallization temperature. The tensile yield strength of the composites was higher than that of HDPE. Sphere-like CaCO3 is the best form in improving the thermal stability and cubic CaCO3 can cause negative effect to the toughness. The impact strength of the composites is significantly increased with decreasing CaCO3 particle size. SEM examination of the fractured surfaces of the composites shows that CaCO3 reacted in cavitations and “lance” functions which increase the impact strength of the HDPE/CaCO3 composites.

Aqueous biphasic systems composed of ionic liquids and sodium carbonate as enhanced routes for the extraction of tetracycline

Aqueous biphasic systems (ABS) using ionic liquids (ILs) offer an alternative approach for the extraction, recovery, and purification of biomolecules through their partitioning between two aqueous liquid phases. In this work, the ability of a wide range of ILs to form ABS with aqueous solutions of Na2 CO3 was evaluated. The ABS formed by IL + water + Na2 CO3 were determined at 25°C, and the respective solubility curves, tie-lines, and tie-line lengths are reported. The studied ILs share the common chloride anion, allowing the IL cation core, the cation isomerism, the presence of functionalized groups, and alkyl side chain length effects to be evaluated. An increase in the cation side alkyl chain length leads to a higher ability for liquid-liquid demixing whereas different positional isomers and the presence of an allyl group have no major influence in the phase diagrams behavior. Quaternary phosphonium- and ammonium-based fluids are more able to form an ABS when compared with imidazolium-, pyridinium-, pyrrolidinium-, and piperidium-based ILs. Moreover, the presence of an aromatic cation core has no major contribution to the formation of ABS when compared to the respective nonaromatic counterparts. Finally, to appraise on the systems applicability in downstream processing, selected systems were used for the partitioning of tetracyclines (neutral and salt forms) - a class of antibiotics produced by bacteria fermentation. Single-step extraction efficiencies for the IL-rich phase were always higher than 99% and confirm the great potential of ILs to be applied in the biotechnological field.

Diamond - ECM Grinding of Ceramic-Metal Tungsten

The reasoning of the diamond electrochemical grinding (DECMG) method of machining of rectangular ceramic metal - tungsten base plates (the surface 80-500 mm2) with their vacuum fastening on the table of the machine-tool is stated. The optimal grinding conditions using the cup diamond wheel bonded by the Cu-Al-Zn base in the electrolyte an aqueous solution of Na2HPO4 and Na2CO3 with additives are given. Depending on the relative position of the work- piece and the grinding wheel the electrode voltage was variable from 2.5V up to 5V, and the electrolyte flow rate supplied through two nozzles was variable too. The characteristics of DECMG in various processing zones as well as components that make stock removal during the double, forward and backward strokes of the machine-tool table are shown. Due to the machining of the plates using delicate grinding conditions they managed to have their predeter- mined sizes, surface roughness, the structure of the surface layers, the reflection power, the absence of defects and service life of the plates. Plates were machined following the request of a research organization for applications in the nuclear and thermonuclear technology. Information can be useful for researchers and developers of physical, chemi- cal and combined methods of machining.

Room temperature synthesis of Mn3O4 nanoparticles: characterization, electrochemical properties and hydrothermal transformation to γ-MnO2 nanorods

A mild and room temperature route has been developed for the synthesis of Mn3O4 nanoparticles by mixing the aqueous solution of MnSO4 and Na2CO3. The Mn3O4 products were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical tests. A specific capacitance of 205Fg−1 was obtained for Mn3O4 nanoparticles at a current density of 0.5Ag−1 in 1M Na2SO4 electrolyte solution. The Mn3O4 nanoparticles exhibited a good rate capability and electrochemical stability. In addition, γ-MnO2 nanorods were prepared from Mn3O4 nanoparticles by a simple hydrothermal treatment at 120°C under the acidic condition.

The Research of Permanent Magnetic Field Treatment on the Iron & Steel Industry Circulating Water Impacts of Stability Index

Iron & steel industrial circulating water system there is a scaling and corrosion problems, the system fouling or corrosion may be judged by monitoring the water quality Stability index. In this paper, we use the magnetic treatment equipment developed by us in the laboratory to simulate the physical treatment process of magnetic field on the industrial circulating water system, and the experimental data is analysis by two-way ANOVA. We have found that: when the circulating water is tap water: (1) if water velocity is 0.6m/s, the magnetic field intensity, magnetic treatment time has a significant influence on the PSI, PSI decline with the magnetic field processing time to increase , and the PSI as well as the time have a good linear relationship; (2) if water velocity is 1.2m/s, the magnetic field strength has a significant influence on the PSI; (3) if water velocity is 2.3m/s, the magnetic field intensity and time has a significant effect for the PSI; when the magnetic field strength is 3.4T, and reaction time is 5 h, PSI is close to 6, water quality is stable; (4) speed and the magnetic field there is an interaction for PSI, that the magnetic field strength and speed of circulating water changes in the PSI also. When the circulating water is CaCl2 and Na2CO3 aqueous solution configuration: as water velocity is 1.2m/s and well as 2.3m/s, the magnetic field strength and time has a significant effect on the PSI .The results show that: iron & steel industrial circulating water system be deal with by proper the magnetic field treatment can control the PSI. The appropriate range PSI of the circulating water can reduce the fouling and corrosion damage, it is significant to develop circulating water system quality control model.

Improved performance of dye-sensitized solar cells with surface-treated TiO2 as a photoelectrode

We report on the effects of surface-modified TiO2 on the performance of dye-sensitized solar cells (DSSCs). TiO2 surface was modified with Na2CO3 via a simple dip coating process and the modified TiO2 was applied to photoelectrodes of DSSCs. By dipping of TiO2 layer into aqueous Na2CO3 solution, the DSSC showed a power conversion efficiency of 9.98%, compared to that (7.75%) of the reference device without surface treatment. The UV–vis absorption spectra, the impedance spectra and the dark current studies revealed that the increase of all parameters was attributed to the enhanced dye adsorption, the prolonged electron lifetime and the reduced interfacial resistance.

The synthesis and characterization of a new (E, E)-dioxime, its complex formations of the macrobicyclic group, and conformational analysis of the ligands

In this study, 19-nitro-6,7,15,16,23,24-hexahydro-13H,26H-14,25-propanotribenzo-[b,i,o] [1,4,11,14,7,18] tetraoxadiazacycloicosine (3) was synthesized using 6,7,8,9,10,11,17,18-octahydro-5H-dibenzo[e,n][1,4]dioxa[8,12]diazacyclopentadesine (1) and 4-nitro-1,2-bis(2-iodoethoxy)benzene (2) as the starting compounds. Macrobicyclic amine 4 was synthesized by reaction of an aromatic nitro compound with hydrazine hydrate (100%) and palladium (10%)-activated carbon in n-butanol. N1,N2-di-6,7,15,16,23,24-hexahydro-13H,26H-14,25-propanotribenzo[b,i,o][1,4,11,14,7,18]tetraoxadiazacycloicosin-19-yl-N′1,N′2-dihydroxyethane-diimidamide vic-dioxime (6) was synthesized by reaction of cyanogen-di-N-oxide in CH2Cl2, which was obtained from (E, E)-dichloroglyoxime and an aqueous solution of Na2CO3 (0.1 N) with 4. Mononuclear Ni(II), Co(III), and Cu(II) complexes, 7, 9, and 10, were synthesized by reaction of vic-dioxime with NiCl2·6H2O, CoCl2·6H2O, and CuCl2·2H2O, respectively. -Capped mononuclear Ni(II) complex 8 was synthesized by reaction of boron-trifluoride diethyl etherate with mononuclear nickel(II) complex 7 in acetonitrile. The structures of new compounds were determined by elemental analysis, 1H-NMR, 13C-NMR, IR, mass spectroscopic data, and thermal methods (TG/DTA). The conformational analysis of the ligands was performed using DFT and AM1 methods.

Preparation of porous material from waste bottle glass by hydrothermal treatment

Porous materials were prepared from colored waste glass by hydrothermal treatment with Na2CO3 aqueous solution. The resultant specific surface area was approximately 140m2/g at maximum. Specific surface area increased at first, reached a maximum, and decreased gradually to be constant at approximately 60m2/g depending on the period of hydrothermal treatment, irrespective of the concentration of Na2CO3 aqueous solution. However, the period at which the specific surface area reached maximum shortened with an increase in Na2CO3 concentration. On the other hand, the mass of the sample decreased and eventually saturated at approximately 30 mass% of the initial weight during the hydrothermal treatment. Both the dissolution of the mother glass and the formation of crystalline deposits, which were identified as calcite, zeolite-P and analcime, affected the porous structure of the treated samples.

Study on Preparing Light Colored C<sub>9</sub> Petroleum Resins with High Softening Point

Polymerizable C9 fraction was cut by atmospheric distillation of raw C9 fraction from thermal cracking. The obtained fraction polymerized using boron trifluoride ethyl ether as catalyst and then the polymerized mixture was washed by warm 10%wt Na2CO3 aqueous solution and distilled water and separated by vacuum distillation for producing light colored C9 petroleum resins with high softening point. The suitable conditions for polymerization process, washing process, vacuum distillation process were investigated to improve the C9 petroleum resins production. Under these conditions, the petroleum resins product with Gardner color index of 4-5 and softening point of 102-120°C could be obtained.

ChemInform Abstract: Synthesis of Lanthanum Carbonate Nanoparticles via Sonochemical Method for Preparation of Lanthanum Hydroxide and Lanthanum Oxide Nanoparticles.

AbstractLa2(CO3)3·1.7H2O nanoparticles are prepared by sonication of aqueous solutions of Na2CO3 and La(OAc)3.

Catalytic activity of Cu–Zn–Al–Mn admixed with gamma-alumina for the synthesis of DME from syngas: manganese effect or just method of preparation?

A series of methanol synthesis catalysts, CuO/ZnO/Al2O3 and CuO/ZnO/Al2O3 containing 5 mol% of manganese physically admixed with γ-Al2O3 were tested for the direct synthesis of dimethyl ether from syngas. The catalysts were prepared by coprecipitation of the metal nitrates with several types of alkali carbonate solution. Aqueous solutions of Na2CO3, NaHCO3/Na2CO3 buffer, and NaHCO3 were used as the precipitating agents to investigate the effects of the preparation method on the microstructure of the precursors and on the physicochemical properties and reactivity of the resulting catalysts. It was found that the most responsible factor in determining the catalytic activity of the methanol synthesis catalyst is the preparation method rather than the incorporation of manganese as the structure modifier. There is a substantial correlation between the copper metal surface area and the activity of the catalyst derived from the structurally active precursor, hydrotalcite-like layered double hydroxides.

Fabrication of hollow poly-allylamine hydrochloride/poly-sodium styrene sulfonate microcapsules from microbubble templates

Hollow microcapsules made of biodegradable polymers have attracted considerable attention as ultrasound contrast agents and carriers in drug delivery systems (DDSs). A hollow polyelectrolyte microcapsule is one of the promising candidates for such applications. Hollow polyelectrolyte microcapsules are normally fabricated by decomposing a core material after forming a capsule shell. Recently, Shchukin et al. (D. G. Shchukin, K. Kohler, H. Mohwald and G. B. Sukhorukov, Angew. Chem., Int. Ed., 2005, 44, 3310–3314) and Winterhalter et al. (M. Winterhalter and A. F. P. Sonnen, Angew. Chem., Int. Ed., 2006, 45, 2500–2502) proposed a fabrication method of hollow polyelectrolyte microcapsules using microbubbles as templates. In this method, stable microbubbles are formed in a surfactant solution by means of an ultrasound generator, and then, a polyelectrolyte is adsorbed on the microbubble surface, yielding hollow polyelectrolyte microcapsules. In this study, we proposed a new fabrication method for hollow poly-allylamine hydrochloride/poly-sodium styrene sulfonate (PAH/PSS) microcapsules without using surfactants. In a Na2CO3 aqueous solution, PAH becomes colloidal particles of R-NHCOO− and R-NH3+ within a certain pH range. Under such a condition, if microbubbles are generated in the solution, the colloidal particles adsorbed on the microbubble surface stabilize the microbubbles. When PSS is added to the solution sequentially, a bilayer of PAH/PSS can be formed around microbubbles. We successfully fabricated hollow PAH/PSS microcapsules by this method and elucidated the conditions required for the formation of colloidal particles of PAH and a bilayer of PAH/PSS.

Quench hardening of 0·4%C steel using aqueous electrolyte plasma as heat source

Quench hardening of 0·4%C steel has been achieved using aqueous electrolyte plasma as heat source. Cylindrical specimens (8 mm diameter) of 0·4%C steel (cathode) were placed at the centre of a cylindrical stainless steel ring of 100 mm diameter (anode) in 15 wt-%Na2CO3 aqueous solution. Continuous electrolyte plasma was generated by electrical discharge at voltages higher than ∼90 V in a narrow layer at the specimen (cathode) surface. The aqueous electrolyte plasma caused rapid heating of the active electrode (cathode) to 900–1200°C in few seconds at applied voltages in the range of 95–140 V. On subsequent rapid cooling, the steel specimen transformed to martensite structure. The process can be adopted for surface modification techniques such as nitriding and carburising. Feasibility of anodising using this technique may also be explored.

Effect of temperature on crystallinity of carbonate apatite foam prepared from α-tricalcium phosphate by hydrothermal treatment

The effect of temperature on crystallinity of carbonate apatite (CAp) foam prepared from alpha-tricalcium phosphate (alpha-TCP) foam by hydrothermal treatment was investigated in the present study. The alpha-TCP foams were prepared through a conventional sintering method using polyurethane foam as template. Then, the resultant alpha-TCP foams were hydrothermally treated with Na2CO3 aqueous solution at 100 degrees C, 150 degrees C and 200 degrees C for 72 h. After hydrothermal treatment, the cancellous bone-like macroporous structure of the alpha-TCP foams was maintained. However, microscopic morphology of the foams' frame significantly changed after the 72 h treatment period. The smooth surface of alpha-TCP foam disappeared and the whole surface was covered with plate-like deposits. The plate-like deposits treated at 150 degrees C and 200 degrees C had smooth surface while those treated at 100 degrees C were constructed from spherical particles of approximately 200 nm in diameter. The results of X-ray diffraction and Fourier transform infrared analysis showed that alpha-TCP was completely converted to CAp and the crystallinity of CAp prepared at 100 degrees C was significantly lower than those prepared at 150 degrees C and 200 degrees C. Hydrothermal treatment of alpha-TCP foam at 100 degrees C allowed the formation of low-crystalline CAp foam but complete conversion needs a longer treatment period.

Alumina Extraction from Mexican Fly Ash

ABSTRACTTwo alternative chemical methods are studied for the extraction of Al2O3 from Mexican Fly Ash (FA). Reaction of FA with H2SO4 at high temperature allows extracting ∼37% of the total Al2O3 contained in the FA as Al2(SO4)3, regardless of H2SO4 concentration, treatment time and temperature employed. This is partly due to the high chemical resistance of mullite (Al6Si2O13) contained in the FA. In contrast, reaction of FA with a CaCO3-Na2CO3 mixture at 1300°C/1h, followed by lixiviation with a Na2CO3 aqueous solution and precipitation of bohemite [AlO(OH)] by addition of either H2O2 or NH4HCO3, allows extracting ∼80% of the total Al2O3 contained in the FA as θ-alumina, after calcination of bohemite at 1200°C/1h.

Fabrication of Tubular Structure Agglomerates of Calcium Carbonate by Using Collodion Film

AbstractA novel and simple method for preparing tubular structure agglomerates of calcium carbonate (CC‐tube) is described. Calcium chloride and sodium carbonate aqueous solutions were used as reactants separated by a collodion film (a nitrocellulose material) in aqueous solution. The effects of the concentrations of calcium chloride and sodium carbonate aqueous solutions on the morphology and phase structure of the as‐obtained samples were investigated. The CC‐tube growth was prevented with the increase of reactant concentration from 0.5 to 1.0 mol·L−1. Compared with Na2CO3 aqueous solution, it is favourable to grow calcite crystals in CaCl2 aqueous solution. The products were characterized by X‐ray diffraction, Fourier transform infrared spectroscopy and scanning electron‐ microscopy.

Protein-Calcium Carbonate Coprecipitation: A Tool for Protein Encapsulation

A new approach of encapsulation of proteins in polyelectrolyte microcapsules has been developed using porous calcium carbonate microparticles as microsupports for layer-by-layer (LbL) polyelectrolyte assembling. Two different ways were used to prepare protein-loaded CaCO3 microparticles: (i) physical adsorption--adsorption of proteins from the solutions onto preformed CaCO3 microparticles, and (ii) coprecipitation--protein capture by CaCO3 microparticles in the process of growth from the mixture of aqueous solutions of CaCl2 and Na2CO3. The latter was found to be about five times more effective than the former (approximately 100 vs approximately 20 mug of captured protein per 1 mg of CaCO3). The procedure is rather mild; the revealed enzymatic activity of alpha-chymotrypsin captured initially by CaCO3 particles during their growth and then recovered after particle dissolution in EDTA was found to be about 85% compared to the native enzyme. Core decomposition and removal after assembly of the required number of polyelectrolyte layers resulted in release of protein into the interior of polyelectrolyte microcapsules (PAH/PSS)5 thus excluding the encapsulated material from direct contact with the surrounding. The advantage of the suggested approach is the possibility to control easily the concentration of protein inside the microcapsules and to minimize the protein immobilization within the capsule walls. Moreover, it is rather universal and may be used for encapsulation of a wide range of macromolecular compounds and bioactive species.

Chemo-Hydrodynamical Instability Created by CO2 Absorption in an Aqueous Solution of NaHCO3 and Na2CO3

CO2 absorption in an initially quiescent aqueous solution of NaHCO3 and Na2CO3 is studied in a Hele-Shaw cell. Using a Mach-Zehnder interferometer, refractive index variations in the liquid are followed during the absorption. It is shown that chemo-hydrodynamical instabilities appear in the liquid phase below the interface. A description of the observations and a preliminary simple modeling of this instability is presented in this paper. It is found that the conjecture that the Rayleigh-Taylor mechanism takes part in triggering the convection is not incompatible with the observed behavior.

Thermal Conductivity of Aqueous Na2CO3 at High Temperatures and High Pressures

The thermal conductivity of three aqueous Na2CO3 solutions of molality (0.4966, 1.0483, and 1.6650) mol·kg−1 has been measured with a concentric-cylinder (steady-state) technique. Measurements were...