Sulfuric Acid Salts Research Articles

Diazonium-induced anchoring process: an application to improve the monovalent selectivity of cation exchange membranes

An efficient and one-step chemical process (diazonium-induced anchoring process) to graft covalently a thin polyaniline-like layer on the surface of the Selemion CMV commercial cation exchange membrane is reported. SEM, IR and XPS techniques were used to characterize the obtained polymer film. The ability of such a surface modification layer to improve the membrane selectivity for hydrogen ions was confirmed by means of electrodialysis test. In contact with a mixed solution of sulfuric acid and metallic divalent salts, the protonation reaction of the polyaniline-like layer creates positive charges, thus leading to an electrical repulsion barrier which may reduce the penetration of divalent cations with respect to hydrogen ions. The ion exchange capacity, the membrane conductivity as well as the competitive transport of nickel and proton ions inside the modified membrane are discussed in detail in comparison with those of the bare membrane.

Electrodeposition of platinum-ruthenium nanoparticles on carbon nanotubes directly grown on carbon cloths for methanol oxidation

Dense carbon nanotubes (CNTs) were grown via a thermal chemical vapor deposition (CVD) process on titanium treated carbon cloths. Platinum-ruthenium (Pt-Ru) nanoparticles were then deposited on the CNT surfaces by potentiostatic electrodeposition in mixed sulfuric acid and ethylene glycol (EG) containing aqueous electrolytes. After the deposition process, the surface morphology of prepared specimens was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the electrochemical characteristics of the specimens were investigated by cyclic voltammetry (CV) in mixed sulfuric acid and methanol aqueous solutions saturated with nitrogen. Finely dispersed Pt-Ru nanoparticles were observed on the surfaces of the CNTs directly grown on carbon cloths. It was also observed that the performance of the Pt-Ru catalysts in terms of methanol oxidation efficiency and suppression of carbon monoxide adsorption would be influenced by the concentrations of sulfuric acid, EG, and Ru precursor salt during the electrodeposition processes.

Concentration effects in copolymerization of sulfuric acid salt of N,N-dimethylaminoethyl methacrylate with acrylonitrile and acrylamide in aqueous solutions

Copolymerization of sulfuric acid salt of N,N-dimethylaminoethyl methacrylate with acrylonitrile and acrylamide in aqueous solution was studied.

Investigation on influence of sodium- or strontium-modification on corrosion-resistance of Al–11.7%Si alloy

Weight loss test in 4% sulfuric acid aqueous solution bath and salt spray test with 5% NaCl aqueous solution were used to evaluate the corrosion resistance of Al–11.7 wt%Si alloys with no modification, sodium modification, or strontium modification. SEM and optical microscopy were used to, respectively, observe the surface and depth corrosion morphologies of the alloys. The results showed that the corrosion-resistance of the alloy with no modification was the best, followed by the Sr-modified alloy, with the Na-modified alloy showing the worst results. Up to 360 h duration in 4% sulfuric acid aqueous solution bath, all the three alloys showed uniform corrosion characteristics. However, after 360 h duration, pitting corrosion became the typical characteristic of the modified alloys and it resulted in a considerable increase in percentage weight loss. After 480 h, the depth of the pitting holes in the Sr-modified alloy was larger than that in the Na-modified alloy, but the transverse corrosion channels in the former were far less than those in the latter. After this duration, the well-developed transverse corrosion channels in the Na-modified alloy became interconnected inch by inch, which led to severe exfoliation corrosion, so the percentage weight loss of the Na-modified alloy rose abruptly.

An efficient method for the α-phenylhydrazation of heterocyclic systems under mild and heterogeneous conditions

A combination of silica modified sulfuric acid and aryldiazonium salt was used as an agent for the α-phenylhydrazation of 2-ketomethylquinoline under mild and heterogeneous conditions to provide moderate to excellent yield.

Liquefaction of CCA-treated wood and elimination of metals from the solvent by precipitation

Abstract Spent chromated copper arsenate (CCA)-treated wood was liquefied in polyethylene glycol 400/glycerin (2:1w/w). Sulfuric acid (95–98%) and ferrous salts (FeSO4·7H2O or FeCl2·4H2O) were used as catalysts and additives, respectively. The resulting liquefied CCA-treated wood was diluted with aqueous solvents and was then mixed with complexion/precipitation agents, followed by precipitation or filtration to remove the toxic metal-bearing sediment. As a result, more than 90% of Cu, Cr or As was removed.

Polyaniline‐Supported Sulfuric Acid Salt as a Powerful Catalyst for the Protection and Deprotection of Carbonyl Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Kinetics of acetic acid esterification with 2-ethoxyethanol over an Al-pillared clay catalyst

The Al-pillared clay catalyst obtained by exposing activated clay powder to sulfuric acid and aluminium salts and calcining in air at 373 - 673 K, was found to be highly active for the title reaction. The results indicated that pillared layer clay of the mixed oxide has been employed as parent catalysts for their definite structure and special properties which can be modified by the substitution of L and B acid sites cations. Solid acid catalyst of supported aluminium was found to be highly active and selective at the 373 - 473 K temperature range for heterogeneous esterification. The activity is mainly attributed to the Lewis (and a considerably small number of Bronsted) acid sites whose number and strength increased due to pillaring. The water produced in the esterification can be induced by Al3+, which makes the catalyst surface to form strong B acid. Their acidities are obtained by pH measurement. If only B acid sites are > 70%, and pH < 1 in the 2-ethoxyethanol, there exists an activity of esterification. The used catalyst gave identical results with that of the fresh one. X-ray diffraction spectra show that the composition and active phase of the used catalysts are the same as the fresh ones. The kinetic study of the reaction was carried out by an integral method of analysis. The kinetic equation of surface esterification is y = 2.36x - 0.98.

Studies on acrylic acid–grafted polyester fabrics by electron beam preirradiation method. I. Effects of process parameters on graft ratio and characterization of grafting products

AbstractPolyester fabrics were preirradiated by electron beam in air and then grafted by acrylic acid (AA) without excluding oxygen. Effects of preirradiation dose, monomer concentration, reaction temperature, storage time, sulfuric acid, and Mohr's salt were investigated in detail and are discussed. The results suggest that it is practicable and effective to graft AA onto polyester fabrics by means of the preirradiation method. FTIR and SEM were used to characterize AA‐grafted polyester fabrics. A new band appearing at 1546 cm−1 in the FTIR spectrum implies that AA was indeed introduced onto PET macromolecules. Changes of the diameter and the surface structure of fabric fibers presented in SEM micrographs make it clear that a layer of grafted poly(acrylic acid) was formed on the surface of these PET fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3931–3938, 2003

Polyaniline-Supported Sulfuric Acid Salt as a Powerful Catalyst for the Protection and Deprotection of Carbonyl Compounds

Structurally different carbonyl compounds were converted into their corresponding cyclic acetals using polyaniline-sulfate salt as catalyst in dry toluene in excellent yield. In turn, useful deacetalization in aqueous medium was demonstrated. Chemoselective protection of carbonyl compounds was also demonstrated. The advantages of the polyaniline-sulfate salt are ease of preparation and handling, stability, reusability and activity.

Radiation-induced grafting of methylmethacrylate onto ultrahigh molecular weight polyethylene and its adhesive characteristics.

The surface of ultrahigh molecular weight polyethylene (UHMWPE) was modified by radiation-grafting methylmethacrylate (MMA) in the presence of sulfuric acid and metallic salt to increase bonding strength with polymethylmethacrylate. The effect of the addition of metallic salts and sulfuric acid on the radiation grafting reaction was investigated when MMA was grafted to the irradiated UHMWPE. The adhesive characteristics with the grafting yield were investigated using conventional acrylic bone cement based on poly(methyl methacrylate) [PMMA]. The results showed that the inclusion of an FeSO4 . 7H2O and sulfuric acid in MMA grafting solutions was extremely beneficial and led to a most unusual synergistic effect, while CuSO4 . 5H2O led to a detrimental effect. The tensile bonding strength between UHMWPE and PMMA sheet increased remarkably with an increased grafting yield on UHMWPE surfaces.

Electrochemically induced redox polymerization of acrylamide

Polymerization of acrylamide (AA) has been studied in aqueous solution in the presence of Ce(IV) salt-oxalic acid initiator system in an electrochemical cell with and without separation of anolyte and catholyte. For reactions that required the cathode and anode sections to be analyzed individually, a cell whose compartments were divided by a sintered glass disk of the medium porosity was employed. Polymerization was initiated by a free radical that is formed by the fast reaction of oxalic acid and Ce(IV). The electrolysis of the reaction solution results in regeneration of Ce(IV), which can oxidize oxalic acid to produce radicals. The effect of sulfuric acid and cerium (IV) salt concentration and temperature on the yield of electroinitiated polymerization in different cell designs and structural identification of products were performed. Reaction was also followed by cyclic voltametric measurements, and a mechanism was proposed. Results indicated that the electrolysis method with a divided cell (85% conversion) shows advantages, compared with nonelectrolytic (5% conversion) and with undivided electrochemical cell (25% conversion) methods where a high concentration of initiator was used.

Reactive extraction of phenols using sulfuric acid salts of trioctylamine

An experimental study of phenol and o-cresol reactive extraction using sulfuric acid salts of trioctylamine, via emulsion liquid membrane is presented. The effects of carrier concentration and of the volume ratio of phases were investigated. Two models, one proposed by Chaudhury and Pyle (1992) and the second proposed by Yan (1993) were tested. The model predictions are in good agreement with the experimental data.

Three-dimensional Models Represent Seed Moisture Content as a Function of Relative Humidity and Temperature

Seed moisture content (MC) has been considered the most important factor controlling physiological reactions in seeds, and MC changes with relative humidity (RH) and temperature (T). This relationship is revealed by studying the interaction of RH and T at equilibrium. Cucumber (Cucumis sativus L.), lettuce (Lactuca sativa L.), maize (Zea mays L.), onion (Allium cepa L.), pea (Pisum sativum L.), and watermelon (Citrullus lanatus M. &amp; N.) seeds were equilibrated over sulfuric acid (1% RH) and various saturated salt solutions (5.5% to 93% RH) at temperatures from 5 to 50 °C. Best-fit subset models were selected from the complete third-order model MC = β0 + β1*RH + β2*T + β3*RH2 + β4*T2 + β5*RH*T + β6*RH3 + β7*T3 + β8*RH*T2 + β9*RH2*T, using Mallows' minimum Cp as the selection criterion. All six best subset models (R2, 0.98 to 0.99) had the same functional form, MC = β0 + β1*RH + β2*T + β3*RH2 + β5*RH*T + β6*RH3 + β9*RH2*T. Coefficients had essentially the same respective values among all species except onion and pea, for which some coefficients were statistically different from those of the other species (P ≤ 0.05). All models indicated that seed MC increased as RH increased and decreased as T increased; but RH had the greater influence. The inverse relationship between seed MC and T, although slight, was evident in the response surfaces. The interaction effect of RH and T on MC was significant at P ≤0.001. These results suggest that orthodox seed species respond similarly to T and RH. This in turn suggests that a common model could be developed and used for optimizing seed storage environments.

EXTRACTION EQUILIBRIUM OF 2-CHLOROPHENOL BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

ABSTRACT The extraction equilibrium of 2-chlorophenol from an aqueous solution by the sulfuric acid salts of trioctylamine (TOA sulfate salts, or TOA salts) in an organic solvent was investigated. Sulfuric acid first reacts with trioctylamine (TOA) to form the TOA salts; then 2-chlorophenol is extracted into the organic phase from the aqueous phase by the TOA salts. The modified Wilson model, which accounts for the equilibrium of the chemical reaction of trioctylamine and sulfuric acid to form the various TOA salts, was applicable to the reaction in any organic solvent at various temperatures to predict the extraction of 2-chlorophenol. The number of water molecules accompanying the various TOA salts, which reflects the extraction capability of 2-chlorophenol, was determined. The results obtained from the modified model of equilibrium of the chemical reaction of trioctylamine and sulfuric acid are fairly consistent with the experimental data. The effects of the initial concentration of 2-chlorophenol, inorganic acids and organic solvents on the distribution coefficient of 2-chlorophenol were investigated.

Extraction of phenol by trioctylamine sulfate salts through a supported‐liquid membrane

Abstract The technique of the supported‐liquid membrane (SLM) has been employed to remove phenol from aqueous streams. The sulfuric acid salts of trioctylamine (TOA salts), which have been produced from the reaction of trioctylamine (TOA) and sulfuric acid, dissolved in TOA, have been used as the carrier material which filled in the pore of the membrane. 1‐octanol has been added to the organic solution to make it a homogeneous organic solution. The transport of phenol is expressed by the permeability of the phenol which is an index to indicate the extraction capability of phenol through the supported‐liquid membrane. VVLP, GVHP and PP membranes have been employed to examine the characteristics of extraction. Effects of the operating conditions and parameters, such as the initial concentration of phenol in the aqueous phase, the initial concentration of sulfuric acid in the feed solution, the initial concentration of sodium hydroxide in the stripping solution and the initial concentration of TOA salts in t...

Extraction of phenol by sulfuric acid salts of trioctylamine

Abstract The extraction of phenol from an aqueous solution using sulfuric acid salts of trioctylamine (TOA salts) was carried out. Trioctylamine (TOA) dissolved in diisopropyl ether (DIPE) (or 1‐octanol, cyclohex‐ane, benzene and kerosene) was evaluated for extraction of phenol at various volume ratios of organic phase to aqueous phase at varied temperatures. The equilibrium distribution coefficient (KD ) for the extraction of phenol with TOA salts in those diluents was measured. Phenol is extracted by a physical distribution with pure diluent alone and through the interaction between TOA and phenol. The latter was quantitatively interpreted according to a reaction scheme in which adducts of several kinds were composed of trioctylamine and phenol. The TOA salts have a significantly greater extraction capability for phenol than TOA itself. The reaction of phenol and hydroxide ion to form phenoxide ion is used to explain the small extraction of solute at high pH. A simple mathematical model was derived to a...

Extraction Equilibrium of Pyrocatechol by Sulfuric Acid Salts of Trioctylamine

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExtraction Equilibrium of Pyrocatechol by Sulfuric Acid Salts of TrioctylamineMaw-Ling Wang, Ying-I Lin, and Biing-Lang LiuCite this: Ind. Eng. Chem. Res. 1995, 34, 4, 1302–1309Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://doi.org/10.1021/ie00043a035RIGHTS & PERMISSIONSArticle Views134Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (816 KB) Get e-Alerts Get e-Alerts

Radical-Initiated Homopolymerization of Acrylonitrile in the Presence of Ce(Iv)-Hippuric Acid in Iviicellar Phase: A Kinetic Study

Abstract Polymerization of acrylonitrile using Ce(IV) as initiator in the presence of hippuric acid in aqueous sulfuric acid solution catalyzed by N-cetyl trimethyl ammonium bromide (NCTAB) was studied kinetically. The polymerization experiment was carried out in the temperature range 35°-55°C. The rate of polymerization (R p) increases with increasing concentration of NCTAB and it is found to be proportional to the concentration of acrylonitrile. Comparisons were made of the effect of different organic substrates and different miceiles on the rate of polymerization. Various effects such as effects of concentration of metal ion, ernulsi-fier, monomer, sulfuric acid, organic solvents, and inorganic salts on R p were also investigated. The remarkable feature of the investigation involves the enhancement of R p in the presence of micelles; a suitable mechanism for the derivation of the rate expression is proposed and optimum conditions are predicted. From the Arrhenius plot, the energy of activation (E A) wa...

Micellar effect on the kinetics of ceric ion‐initiated polymerization of acrylonitrile in the presence of organic substrate

AbstractThe micellar effect on the kinetics of ceric ion‐initiated polymerization of acrylonitrile (AN) in the presence of N‐acetylglycine has been studied in the temperature range 30–50°C. The neutral emulsifier (Triton X‐100) has no effect on the Rp, whereas both anionic (NaLS) and cationic (NCTAB) emulsifiers accelerate the rate of polymerization appreciably. Comparison of the effect of different organic substrates on the rate of polymerization has been made. Various effects such as the concentration of metal ion, surfactant, monomer, sulfuric acid, organic solvents, and inorganic salts on Rp have also been investigated. The most remarkable feature of the investigation involves the enhancement of Rp in the presence of micelles. A suitable mechanism for the derivation of the rate expression for the above system is proposed along with the calculation of activation energy and prediction of optimum conditions. © 1994 John Wiley &amp; Sons, Inc.