Aqueous Sodium Carbonate Solution Research Articles

A simple and eco-friendly approach for the synthesis of 2-imino and 2-oxo-2H-chromene-3-carboxamides

A series of new 2-imino-2H-chromene-3-carboxamides 5 were synthesized in excellent yield and high atom economy by the Knoevenagel condensation of salicylaldehyde derivatives 4 and N-substituted cyanoacetamides 3 using aqueous sodium carbonate or hydrogen carbonate solution, at room temperature. Treatment of compounds 5 with aqueous HCl led to the formation of the corresponding 2-oxochromenes 6.

Extraction and recovery of penicillin G in a hollow‐fiber membrane contactor

AbstractThe effect of feed pH and temperature were examined for the extraction of penicillin G from aqueous solutions. Equilibrium experiments were first carried out to establish the carrier and the solvent for better extraction in the organic phase. The feed pH was varied in the range 4.5–7 to determine the extractability of the carrier–solvent system. Organic phases consisting of the carriers Aliquat 336 and Amberlite LA‐2 in the solvents Shellsol TK and oleyl alcohol gave good values of the distribution coefficient at room temperature. The distribution coefficients were greater at temperatures higher than the room temperature. Re‐extraction (recovery) experiments were carried out by using an aqueous solution of salts; sodium carbonate performed better than sodium chloride. These processes were scaled up using a pilot‐scale hollow‐fiber membrane module (HFMM). The module (6 cm × 20 cm) had a total of 10 000 microporous polypropylene hollow fibers with an effective mass transfer area of 1.4 m2. The extraction was performed by contacting a ‘feed’ solution containing penicillin G (flowing in the fiber side) with an ‘organic phase’ of Aliquat 336 in Shellsol TK or oleyl alcohol (flowing on the shell side) of the membrane contactor. An organic phase of 5% Aliquat 336 in both the solvents Shellsol TK and oleyl alcohol achieved extraction at pH 7 in the range 40–45% within 1 h at a recirculating feed flow rate of 14.4 l/h. The operating temperature affected the percentage extraction slightly and it increased with temperature before reaching a plateau at 25–30 °C. For recovery of penicillin G from the organic phase, experiments were carried out using aqueous solutions of sodium carbonate and sodium chloride. Sodium carbonate at pH 11.2 gave significantly better recovery (approx. 98%) compared to sodium chloride at pH 6.7 (approx. 38%) within 1.5 h. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.

Synthesis of α-Ni(OH)2 with hydrotalcite-like structure: Precursor for the formation of NiO and Ni nanomaterials with fibrous shapes

α-Ni(OH)2 with hydrotalcite-like structure was prepared by precipitation of nickel acetate and sodium carbonate aqueous solution with the mediation of ethylene glycol at 393 K. Thermal calcination of this nickel hydroxide precursor at 573–1073 K resulted in the formation of fibrous nickel oxides with diameter of 4–8 nm and length of several hundreds of nanometers. Further reduction of these NiO samples with hydrogen at 773 K led to the formation of metallic Ni with fibrous-like morphology. Most promisingly, these novel nanostructured Ni materials showed much higher catalytic activities not only for the decomposition of methane to hydrogen and carbon nanofibers, but also for the hydrogenation reactions of unsaturated organic compounds.

Formation Process and Thermodynamic Poperties of Calcite

AbstractThe fast mixing of aqueous solutions of calcium chloride and sodium carbonate resulted in crystalline forms of vaterite and calcite under vigorous stirring. Then, the vaterite was transformed to pure calcite within about 180 min. The crystalline forms all grew with experimental time increase. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), and X‐ray diffraction spectroscopy (XRD) techniques were employed to characterize the as‐prepared samples. The heat capacity of the stable as‐synthesized calcite was determined by means of an adiabatic calorimeter from 80 to 390 K. The thermodynamic functions of the calcite were derived based on the relationships among the thermodynamic functions and the function of the measured heat capacity with respect to temperature.

Synthesis of nano-sized porous γ-alumina powder via a precipitation/digestion route

Abstract As a part of a study for the preparation of nano-sized γ-Al 2 O 3 powder with controlled porosity and pore size distribution, a precipitation/digestion route was exploited to generate a boehmite precursor having a narrow size distribution of spherical nano-sized particles: size 3.5 nm with surface area ∼261 m 2 /g, average pore diameter of 4.86 nm, and pore volume ∼0.377 cm 3 /g. In this route, aqueous solution of aluminum nitrate and sodium carbonate were added simultaneously drop by drop to a well-stirred 200 ml volume of deionized water (taken in a round-bottom flask) at 70 °C to precipitate boehmite precursor in the pH range of 7.5–8.5 after digestion at the same temperature for 3 h. The boehmite precursor thus obtained is further washed with deionized water first to avoid ‘Na’ contamination and then by ethanol/acetone. The digested precipitate was finally air dried at room temperature. The calcinations of as-dried boehmite precursor at 550 °C/5 h in air produced porous nano-sized γ-Al 2 O 3 powder particles having spherical shape with size of 4.5 nm. These powder particles showed BET surface surface area ∼220 m 2 /g with average pore diameter of 7.0 nm and pore volume ∼0.487 cm 3 /g. However, room temperature precipitation/digestion produces non-crystalline boehmite that gave poorly crystallized γ-Al 2 O 3 powder particles with lower surface area ∼133.90 m 2 /g; these had higher average pore diameter of 26.67 nm with pore volume of 1.02 cm 3 /g. In methanol conversion to DME reaction, γ-Al 2 O 3 catalyst made from precipitation/digestion at 70 °C gave a similar yield of DME when compared with the yield for γ-Al 2 O 3 prepared from commercial Catapal-B boehmite sample.

ダイオキシン汚染土壌からのダイオキシン抽出法およびＲｕ・α‐Ｆｅ・Ｆｅ３Ｏ４複合粒子による抽出ダイオキシンの分解

To carry out the decomposition of chlorinated aromatic compounds such as dioxins, which are hard to decompose at room temperature, nanoscale α-Fe · Fe3O4 composite particles were synthesized via α-FeO(OH) obtained by the reaction of ferrous sulfate and sodium carbonate aqueous solutions and contained 0.25 wt% precious metals (Pt, Pd, Rh and Ru). As the result of the decomposition of chlorobenzene (CB) using the composite particles containing precious metals, it was shown that Rh · α-Fe · Fe3O4 and Ru · α-Fe · Fe3O4 composite particles exhibit superior dechlorination function. Ru · α-Fe · Fe3O4 composite particles were selected because of their low price. For the application of dioxin decomposition at room temperature in contaminated soil, an extractive reagent was selected. Successively, the decomposition of dioxins in extracted-reagent- suspended soil using Ru · α-Fe · Fe3O4 composite particles was carried out at room temperature for seven days, and the initial Toxicity Equivalency Quantity (TEQ) values of dioxins in the solvents and soils decreased to 41-63% after the decomposition.

Novel Ni catalysts for methane decomposition to hydrogen and carbon nanofibers

Novel nickel oxides with controlled crystalline size and fibrous shape were successfully prepared by precipitation of nickel acetate and sodium carbonate aqueous solution with the mediation of ethylene glycol. The precipitation media and temperature were found to play crucial roles in determining the crystalline size and shape of the nickel oxides. The NiO prepared in the aqueous solutions exhibited mainly spherical particles with few nanorods, whereas the NiO samples prepared in the solution of ethylene glycol could be of spherical, fibrous, or nanorod shape, depending on the precipitation temperature. In particular, the nickel hydroxide precipitate obtained in the solution of ethylene glycol at 393 K was α-Ni(OH) 2 with hydrotalcite-like structures; further calcination of this precipitate at 573–1073 K resulted in the formation of nickel oxides with similar fibrous shapes and crystalline size of 3.0–8.1 nm. Similar metallic Ni crystalline size of about 11 nm and fibrous structure were obtained by reduction of these NiO samples with hydrogen at 773 K. When further exposed to the reaction of methane decomposition, the metallic Ni crystallines still exhibited similar evolution behavior and rapidly stabilized at the critical size of 17–18 nm. Consequently, very close catalytic activities for methane decomposition over these novel Ni catalysts were observed with the carbon yields of 354–398 g C/g Ni. The Ni crystallines departed from the fibrous structures and gradually aggregated into particles by the dissociation of the deposited carbons. These nickel particles were then highly dispersed on the in situ produced carbon, which can inhibit the further growth of nickel particle. As a result, the initial fibrous structure morphology of the metallic nickel was gradually turned into pear-like shapes.

Properties of Amorphous Calcium Carbonate and the Template Action of Vaterite Spheres

The fast mixing of aqueous solutions of calcium chloride and sodium carbonate could immediately result in amorphous calcium carbonate (ACC). Under vigorous stirring, the formed ACC in the precipitation system will dissolve first and, then, transform within minutes to produce crystalline forms of vaterite and calcite. After that, the solution-mediated mechanism dominates the transformation of the thermodynamically unstable vaterite into the thermodynamically stable calcite. Although ACC is the least stable form of the six anhydrous phases of calcium carbonate (CaCO(3)), it could be, however, produced and stabilized by a variety of organisms. To better understand the formation-transformation mechanism of ACC and vaterite into calcite, ex-situ methods (i.e., scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction spectroscopy) were used to characterize the formation-transformation process of ACC and vaterite in aqueous systems without organic additives, showing that ACC sampled at different conditions has different properties (i.e., lifetime, morphology, and spectrum characterization). It is also very interesting to capture the obviously polycrystalline particles of CaCO(3) during the transformation process from vaterite to calcite, which suggests the formation mechanism for the calcite superstructure with multidimensional morphology.

Positive-Working Photosensitive Alkaline-Developable Polyimide Precursor Based on Semi-Alicyclic Poly(amide acid), Vinyl Ether Crosslinker, and a Photoacid Generator

A positive-working photosensitive polyimide based on semi-alicyclic poly(amide acid) (PAA), 1,1,1-tris(4-[2-(vinyloxy)ethoxy]phenyl)ethane (TVPE) as a crosslinking dissolution inhibitor and a photoacid generator has been developed. PAA was prepared from pyromellitic dianhydride and alicyclic diamine in N,N-dimethylacetamide (DMAc), which has excellent transparency above 365 nm and good solubility for 1 % sodium carbonate aqueous solution (aq.). The resist from the polymerization solution was formulated with photosensitive additives without isolation of PAA. A 23 μm thick film of the PSPI precursor system containing 25 wt% TVPE, 5 wt% PAG exhibited a sensitivity of 160 mJ/cm2 and contrast of 1.3 when it was exposed to broadband UV light followed by development in a 1 % sodium carbonate aq. at room temperature. A positive image featuring 40 μm line and space patterns was observed by the contact mode.

Comparative Study of Two-Phase Gas-Liquid Flow in the Ejector Induced Upflow and Downflow Bubble Column

A comparative study has been made on the hydrodynamics and gas-liquid mass transfer performances of upflow and downflow bubble columns. Gas-liquid distributions in the column are made by an ejector system using liquid as motive fluid and gas is used as secondary fluid for both the cases. The two-phase hydrodynamic studies have been done with water and aqueous solutions of carboxy methyl cellulose at different concentrations and air as gas phase. The volumetric mass transfer coefficients have been measured by absorbing air-carbon dioxide mixture in aqueous solutions of sodium carbonate and bicarbonate. For downflow system, experiments are carried out at natural suction of air through the ejector; whereas for upflow system, air is forced through the secondary entrance of the ejector from a high pressure tank at any desired rate. The effect of gas and liquid flowrates on gas holdup, frictional pressure drop and mass transfer coefficients have been investigated. All the experiments have been performed in the homogeneous flow regime for a stable operation.

Synthesis of α,α‐Difluoro‐γ‐butyrolactones via Ethyl Iododifluoroacetate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

An aqueous developable photoimageable silver conductor composition for high density electronic packaging

In our preliminary work, we have formulated aqueous developable photoimageable thick film conductor pastes, consisting of ‘ inhouse processed’ submicron sized silver powders (functional material), micron sized lead borosilicate glass frits (permanent binder), epoxy acrylate resin with pendant –COOH group (base photoimageable polymer/temporary binder/organic vehicle) and 2,2′-dimethoxy-2-phenylacetophenone (photoinitiator). The conductor pastes thus formulated were manually screen printed on the alumina substrates, dried, exposed to the ultra-violet light through the desired test patterns, developed in a 1% aqueous sodium carbonate solution, and subjected to a standard one-hour thick film firing cycle. Solid content of the polymer appears to influence the paste performance. Prima facie observations indicate that the paste with the organic:inorganic ratio of 28:72 (corresponding to solid content of 89.9% of the polymer system) exhibits better electrical conductivity, relatively smooth surface finish and line/space resolution of 100 μm with ±5 μm accuracy. Investigations related to the effect of glass content on the properties of photoimageable conductor paste are also furnished in this communication.

The Hidden Equilibrium in Aqueous Sodium Carbonate Solutions − Evidence for the Formation of the Dicarbonate Anion

AbstractCrossover 13C NMR experiments between [13C]carbonate and [18O]carbonate in aqueous solution confirm the combined action of two oxygen‐exchange modes. The isotopomeric carbon dioxides formed in the hydrolysis equilibrium of the labeled carbonate anions react with hydroxide with formation of hydrogencarbonate and with isotopomeric carbonate anions yielding the corresponding dicarbonate species, which, in the back reaction, form carbon dioxide and carbonate anions with distributed oxygen. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Synthesis of α,α-difluoro-γ-butyrolactones via ethyl iododifluoroacetate

A novel synthesis of α,α-difluoro-γ-butyrolactones was realized by the alkaline hydrolysis of the adducts of ethyl iododifluoroacetate and alkenes. Ethyl iododifluoroacetate reacted with alkenes in the presence of sodium dithionite to give the addition products in 62–78% yields. The products were hydrolyzed in 10% aqueous sodium carbonate solution to give α,α-difluoro-γ-butyrolactones in 93–98% yields.

Photoimageable silver paste for high density interconnection technology

We have formulated aqueous developable photoimageable thick film conductor pastes, which comprised of in-house processed submicron-sized silver powder (functional material), micron-sized lead borosilicate glass frit (permanent binder), epoxy acrylate resin with pendant –COOH group (base photoimageable polymer/temporary binder/organic vehicle) and 2,2′-dimethoxy-2-phenylacetophenone (photoinitiator). The conductor paste thus formulated was manually screen-printed on alumina substrate, dried, exposed to ultraviolet light through the desired test pattern, developed in 1% aqueous sodium carbonate solution and subjected to standard 1 h thick film firing cycle. The resultant samples were investigated for surface morphology, thermal behavior and electrical conductivity. Solid content of the polymer appears to influence the paste performance. Prima facie observations indicate that the paste corresponding to polymer solid content of 89.9% and organic:inorganic ratio of 28:72 exhibits better electrical conductivity, thermal stability, relatively smooth surface finish and line/space resolution of 100 μm with ±5 μm accuracy.

Synthesis, Structures and Catalytic Properties of Bis(2‐pyridylimino)‐ isoindolatopalladium Complexes

AbstractReaction of the bis(2‐pyridylimino)isoindole derivatives (10‐Me)‐BPI (1a), (11‐Me)‐BPI (1b), (11‐Br)‐BPI (1c), (4‐Me)‐BPI (1d) and 4‐Me‐10‐tBuBPI (1e) with [PdCl2(PhCN)2] and triethylamine in benzene gave the square‐planar palladium(II) complexes [PdCl{(10‐Me)‐BPI}] (2a), [PdCl{(11‐Me)‐BPI}] (2b), [PdCl{(11‐Br)‐BPI}] (2c), [PdCl(4‐MeBPI)] (2d) and [PdCl(4‐Me‐10‐tBuBPI)] (2e), respectively. Extraction of the crude product 2b with aqueous sodium carbonate solution led to the formation of the dinuclear carbonato‐bridged complex [{(11‐Me‐BPI)Pd}2(μ‐CO3)] (3) which was characterized by an X‐ray structure analysis. Reaction of 11‐Br‐BPI (1c) with a large excess (6 equiv.) of the acetylenes Me3SiCCH, Ph3SiCCH and PhCCH under Sonogashira conditions gave the alkynylated derivatives 11‐(Me3SiCC)‐BPI (4a), 11‐(Ph3SiCC)‐BPI (4b) and 11‐(PhCC)‐BPI (4c), which were metallated with bis(benzonitrile)dichloropalladium(II) to yield the PdII complexes [PdCl{11‐(Me3SiCC)‐BPI}] (5a), [PdCl{11‐(Ph3SiCC)‐BPI}] (5b) and [PdCl{11‐(PhCC)‐BPI}] (5c), respectively. The activity of 2b in the catalytic hydrogenation of C=C double bonds was tested for the reaction with styrene, 1‐octene and cyclohexene. The stability of the palladium complex, the reproducibility of the reaction kinetics, the different behaviour towards the three olefins chosen as substrates, as well as the possibility of isolating the non‐decomposed catalyst after several catalytic runs, provides circumstantial evidence for molecular catalysis with the BPI‐palladium complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Solid-phase extraction and amperometric determination of nitrite with polypyrrole nanowire modified electrodes

In this paper, the electrochemical solid-phase extraction (EC-SPE) and amperometric determination of nitrite with polypyrrole (PPy) nanowire modified electrode was reported. The PPy nanowire modified electrode was prepared by template-free method in a mixture of sodium carbonate and sodium bicarbonate aqueous solution and then conditioned in 0.10 M perchlorate acid for 24 h. EC-SPE (preconcentration) of nitrite ions was conducted under the condition of applied potential 0.800 V for 300 s. The electroreduction of nitrite was conducted under the condition of −0.200 V for 100 s in the solution of 0.50 M H 2SO 4. The length of nanowires, the temperature and the pH of the test solution, the EC-SPE potential and time have significant effects on the corresponding current. Under a certain condition, the relationship between nitrite concentration and corresponding current density is in good linearity. The determination sensitivity may be varied according to the modification parameters. Under the experimental condition, the highest corresponding sensitivity is 55.84 mA/M cm 2, and may be further improved by modification the electrode with longer polypyrrole nanowires.

Time-resolved SAXS study of the effect of a double hydrophilic block-copolymer on the formation of CaCO3 from a supersaturated salt solution.

The effect of a double hydrophilic block-copolymer additive (made of polyaspartic acid and polyethyleneglycol, pAsp(10)-b-PEG(110)) on the initial formation of calcium carbonate from a supersaturated salt solution has been studied in situ by means of time-resolved synchrotron small-angle X-ray scattering (SAXS). A stopped-flow cell was used for rapidly mixing the 20 mM aqueous reactant solutions of calcium chloride and sodium carbonate. In reference measurements without polymer additive the very rapid formation of primary, overall spherical CaCO(3) particles with a radius of ca. 19 nm and a size polydispersity of ca. 26% was observed within the first 10 ms after mixing. A subsequent, very rapid aggregation of these primary particles was evidenced by a distinct upturn of the SAXS intensity at smallest angles. During the aggregation process the size of the primary particles remained unchanged. From an analysis of the absolute scattering intensity the mass density of these particles was determined to 1.9 g/cm(3). From this rather low density it is concluded that those precursor particles are amorphous, which has been confirmed by simultaneous wide-angle X-ray diffraction measurements. Upon adding 200 pm of the block-copolymer no influence on the size, the size polydispersity and morphology of the primary particles, nor on the kinetics of their formation and growth, was found. On the other hand, the subsequent aggregation and precipitation process is considerably slowed down by the additive and smaller aggregates result. The crystalline morphology of the sediment was studied in situ by WAXS ca. 50 min after mixing the reactants. Several diffraction rings could be detected, which indicate that a transformation of the metastable, amorphous precursor particles to randomly oriented vaterite nanocrystallites has taken place. In addition, a few isolated Bragg spots of high intensity were detected, which are attributed to individual, oriented calcite microcrystals that nucleated at the wall of the capillary.

High-pressure and high-temperature Raman spectroscopy of carbonate ions in aqueous solution

Two aqueous solutions of sodium carbonate (0.5 and 2 m) have been studied by in situ Raman spectroscopy in the 1–30 GPa, 25–400 °C pressure–temperature ( P– T) range, in an externally heated diamond anvil cell. Neither bicarbonate ions nor CO 2 species were observed; carbonate ions were found to be the major species in these solutions over the entire P– T range investigated, which proved to be an important constraint for further modelling of deep H 2O–CO 2 fluids. It was shown that sodium carbonate in ice VII is not present as segregated Na 2CO 3 but rather as stable or metastable solid solution or as a hydrate. In order to provide thermodynamical data on carbonate-bearing fluids and natural fluid inclusions, the pressure dependence of the frequency mode of the CO 3 2− symmetric stretching mode was measured at different temperatures in carbonate-bearing liquid water and in ice VII. The pressure-induced frequency shifts of this mode are significantly greater in liquid water than in ice VII and solid carbonates. From these data and using appropriate equation of state (EOS) for volume calculations, the Grüneisen parameters and intrinsic anharmonicity parameters of carbonate ions in water and in ice VII were calculated at different temperatures. Grüneisen parameters of the CO 3 2− symmetric stretching mode are significantly smaller in liquid water than in crystalline carbonates. Intrinsic anharmonicity parameters of this mode are similar in liquid water and crystalline carbonate and close to 0, suggesting that internal modes of CO 3 2− groups behave quasi-harmonically in liquid water.

Alginic acids in Lessonia vadosa: Partial hydrolysis and elicitor properties of the polymannuronic acid fraction

Extraction of Lessonia vadosa(Laminariales, Phaeophyta) collectedin three different localities near PuntaArenas in the south of Chile, with 3%aqueous sodium carbonate solutions gave asodium alginate yield in the range3.0–17.7% dry weight. There were markeddifferences in the mannuronic acid toguluronic acid ratio (M/G) (0.21–1.69) inthe alginic acids, samples collected inPuerto del Hambre in winter were composedmainly of mannuronic acid residues. Thealginate samples were characterized bypartial hydrolysis and FT-IR spectroscopy.No relationship was found between tissuetype and polyguluronic acid content. Theelicitor activity of the polymannuronicacid enriched fraction from alginic acid ofblades from Puerto del Hambre was assayedin wheat plants. The polymannuronic acidenriched fraction induced substancialelicitation of phenylalanine ammonia-lyase(PAL) and peroxidase (POD) activities.