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We successfully synthesized trifluoromethylated β-ketosulfones via the reaction of vinyl triflates with alkenes employing aqueous sulfurous acid as an external source of SO2. The PhSSPh/photoinitiated reaction with vinyl triflates that contain electron-deficient groups or halogens did not show any base-related effects, whereas the radical reaction was impeded in the absence of a base in the case of vinyl triflates generated from phenylacetylenes. [ABSTRACT FROM AUTHOR]

Sulfurous acid (H2SO3) is known to be thermodynamically instable decomposing into SO2 and H2O. All attempts to detect this elusive acid in solution failed up to now. Reported H2SO3 formation from an experiment carried out in a mass spectrometer as well as results from theoretical calculations, however, indicated a possible kinetic stability in the gas phase. Here, it is shown experimentally that H2SO3 is formed in the OH radical‐initiated gas‐phase oxidation of methanesulfinic acid (CH3S(O)OH) at 295±0.5 K and 1 bar of air with a molar yield of 53-17+7 ${{53}_{-17}^{+\ 7}}$ %. Further main products are SO2, SO3 and methanesulfonic acid. CH3S(O)OH represents an important intermediate product of dimethyl sulfide oxidation in the atmosphere. Global modeling predicts an annual H2SO3 production of ∼8 million metric tons from the OH+CH3S(O)OH reaction. The investigated H2SO3 depletion in the presence of water vapor results in k(H2O+H2SO3) <3×10−18 cm3 molecule−1 s−1, which indicates a lifetime of at least one second for atmospheric humidity. This work provides experimental evidence that H2SO3, once formed in the gas phase, is kinetically stable enough to allow its characterization and subsequent reactions. [ABSTRACT FROM AUTHOR]

The objective of the research has been to overcome some inherent drawbacks of hemp fiber via chemical modification, which is a vital issue in using it as a textile fiber like cotton. Hemp fiber was modified with treatment liquor (mixture of sulfurous acid and sodium hydroxide) in aqueous medium to remove lignin. The effects of the treatment liquor concentration, fiber to liquor ratio, reaction time and temperature on the percent lignin extracted from hemp fiber were studied. Modified hemp fibers (MHF) were bleached in an alkaline pH aqueous medium with hydrogen peroxide. The process significantly improved lignin removal, bleaching and color fastness. In fact, the whiteness index of bleached MHF was significantly higher than that of bleached raw hemp, but its tensile strength was slightly affected. The photooxidative degradation of hemp fiber was 70% lower than that of unmodified (raw) hemp fiber and almost like that of cotton yarn. The color fastness properties of dyed bleached modified hemp fiber were significantly better than those of dyed bleached unmodified hemp fiber and close to those of dyed bleached cotton yarn. [ABSTRACT FROM AUTHOR]

The influence of the chemical nature of the cluster constituents on the desorption/ionization process was investigated for desorption/ionization induced by neutral SO2 clusters (DINeC). The polar clusters act as a transient matrix in which the desorbed analyte molecules are dissolved during the desorption process. For drop-cast samples, the desorption/ionization efficiency was found to be largely independent of the pH value of the initial solution the samples were prepared from; positive ions were almost always dominant and no multiply charged negative ions were observed. The results were traced back to the interaction of SO2 with water present in the samples. Both H/D exchange experiments and surface charge measurements showed that SO2 from the cluster beam interacts with water on and in the sample forming sulfurous acid. The latter then acts as an efficient proton supply leading to an enhanced ionization efficiency. The results demonstrate the possibility to control the ionization efficiency when using reactive cluster constituents in desorption-based ionization methods such as DINeC and cluster-based secondary ion mass spectrometry. [ABSTRACT FROM AUTHOR]

The SNO- and OSN- anions are shown in this work to be very stable negatively charged species in line with other recent work [T. Trabelsi et al., J. Chem. Phys. 143, 164301 (2015)]. Utilizing established quartic force field techniques, the structural and rovibrational data for these anions are produced. The SNO- anion is less linear and has weaker bonds than the corresponding neutral radical giving much smaller rotational constants. OSN- is largely unchanged in these regards with inclusion of the additional electron. The S-N bondis actually stronger, and the rotational constants of OSN- versusOSNare similar. The vibrational frequencies of SNO- are red-shifted from the radical while those in OSN- are mixed. OSN- has mixing of the stretching modes while theS-NandN-Sstretches of SNO-> are largely independent ofoneanother. Theω3 stretches aremuchbrighter in these anions than theyare in the radicals,but the ω1 stretches are still the brightest. [ABSTRACT FROM AUTHOR]

The formation of sp2 carbon by the Boudouard reaction significantly damages the refractory ceramics. Sulphur is an efficient way to prevent the carbon deposition catalysed by Fe 3 C, in the presence of H 2. Thermogravimetric analysis was carried out on Fe 2 O 3 samples exposed to a CO/H 2 gas mixture at 600 °C. Solid sulphur was mixed with Fe 2 O 3 powder or continually added in the form of gas into the CO/H 2 reducing gas. The samples were characterised by X-ray diffraction, Raman spectroscopy, SEM and TEM. The addition of 100 ppm of sulphur species in the gas prevents the formation of carbon. The mechanism that governs the inhibition of the reaction is proposed, in which the formation of a thin protective FeS layer (0.5–1 nm) is involved. This study paves the way to an effective solution to inhibit the sp2 carbon deposition in the refractories by poisoning the Fe 3 C catalyst with sulphur. [ABSTRACT FROM AUTHOR]

Abstract: This article studies corrosion of 08PS steel in 2 M H2SO4, 2 M H3PO4 and their mixtures (t = 20-80°C). Addition of a mixture comprised of 4.5 mM IFKhAN-92, a triazole derivant, and 0.5 mM KNCS inhibits corrosion of low carbon steel in these media. The existence of Fe(III) in the solutions worsens steel protection by this composition of inhibitors. The most stable against the impact of Fe(III) cations are the solutions of H3PO4 or its mixture with sulfurous acid with high content of H3PO4. Addition of hexamethylenetetramine (0.20 M) to these media enables protection of low carbon steels in acid mixed solutions with high content of H2SO4 (up to 60%) containing Fe(III). Upon etching of steels or acid washing of steel equipment in the case of potential accumulation of Fe(III) salts in such media accelerating metal corrosion, H2SO4 + H3PO4 solutions are recommended containing up to 60% H2SO4 and IFKhAN-92 + KNCS + hexamethylenetetramine composition, since in such a solution steel corrosion is minimized due to its interaction with Fe(III) compounds. [ABSTRACT FROM AUTHOR]

Features of the content and distribution of vanadium and vanadyl porphyrins in the fractions of resins, which were obtained by separation using column chromatography on silica, have been studied on heavy sulfurous oils of various deposits of the Volga-Ural basin (Russia). The difference of the vanadium and vanadyl porphyrin contents in the fractions of oils of various production complexes has been shown. Features of structural-group composition and predominant types of vanadyl porphyrins in the fractions of resins have been determined. [ABSTRACT FROM AUTHOR]

To develop an efficient method for degradation of grape seed and skin proanthocyanidins polymers into oligomers, an optimized sulphurous acid degradation conditions for grape seed with the temperature of 60 °C, reaction time of 60 min and sample-sulphurous acid ratio of 1:0.2, and for grape skin with the temperature of 40 °C, reaction time of 60 min and sample-sulphurous acid ratio of 1:0.2, were established. Afterwards, HSCCC and prep-HPLC were used to fractionate and isolate individual proanthocyanidin oligomers from the degradation products. Total of ten dimeric or trimeric procyanidins were obtained, and most of them presented high yield (from 0.7 mg to 13.6 mg per run in grape seed and from 0.5 mg to 4.1 mg per run in grape skin) and high purity (over 90%). The proposed method provides a new way for large preparation of oligomeric proanthocyanidins from naturally abundant and wasted polymeric ones. [ABSTRACT FROM AUTHOR]

Integrated thermal treatment (coupled pyrolysis and combustion) is considered to be an effective method for the utilization of oil sludge (OS). Characteristics of OS pyrolysis, OS combustion and OS char combustion were comprehensively investigated with a thermogravimetry-mass spectrum (TG-MS) system in this work. Small molecule hydrocarbons like CH 4 were main components in OS pyrolysis gas. Nitrogen and sulfur containing compounds, H 2 O, and CO 2 were detected out during OS and OS char combustion. The maximum intensities of NH 3 , HCN and NO all appeared in the OS combustion. H 2 S was the main precursor of SO 2 , and the peak of H 2 S occurred earlier with an increase in the pyrolysis temperature between 500 and 700 °C. Besides, with an increase in the pyrolysis temperature, NO 2 and SO 2 emissions increased during OS char combustion. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO 2 ) is one of the principal impurities in carbon dioxide (CO 2 ) streams captured from coal-fired power plants, and the synergistic effect of CO 2 /SO 2 on the corrosion of steels has attracted significant recent attention. In this work, the corrosion mechanism of valve steel X80CrSiMoW152, in a mixed CO 2 /sulfurous acid aqueous environment, was investigated. Experiments were conducted by adding different concentrations of sulfurous acid to a CO 2 -saturated solution at 25 °C under different pH conditions. The effect of sulfurous acid on the corrosion mechanism was examined by potentiodynamic scanning. Results revealed that for the anodic reaction, the presence of 100 ppmw sulfurous acid promoted the dissolution of steel in CO 2 -saturated solutions. In the cathodic polarization curve, a “second-wave” phenomenon was observed before the second limiting current for cases with sulfurous acid at pH 3.0 and for the case with 1,000 ppmw sulfurous acid at pH 2.0. These new “waves” were potentially caused by the direct reduction of sulfurous acid or bisulfite ions on the steel surface. The adsorption of sulfurous acid or bisulfite could also impede the reduction of hydrogen by competitive adsorption, and by a decrease in the cathodic-reaction area for the reduction of hydrogen ions. [ABSTRACT FROM AUTHOR]

A novel absorbent sodium lactate (NaLa) aqueous solution (aq) for SO2 absorption is reported. SO2 in simulated flue gas is reversibly absorbed in NaLa aq. The absorption capacity of SO2 in the absorbent increases with increasing NaLa content and SO2 concentration, and decreasing temperature. Compared with the absorbents reported in the literature, the absorption capacity of SO2 in NaLa aq. is much high, for example, 50 wt % NaLa aqueous solution can absorb 0.130 g SO2/g absorbent at a SO2 concentration of 2.5 vol % and 40 °C. Importantly, NaLa (aq) exhibits high reversibility and long-term stability, indicating a promise for the desulfurization of flue gas. The absorption mechanism is proposed to be the replacement of lactic acid (HLa) by sulfurous acid (H2SO3), which is generated by dissolving SO2 in water. [ABSTRACT FROM AUTHOR]

From the perspective of bio-refinery, sulfurous acid (H2SO3) treatment of lignocellulosic biomass is attractive because of its ability to act both as an acid catalyst and as a sulfonation agent. Therefore, its capability to hydrolyze polysaccharides (especially glucan) into monosaccharides was compared with two other acids, hydrochloric and sulfuric acids. The decomposition of methyl α-D-glucopyranoside (MGPα) in these three acids, hydrochloric, sulfuric, and sulfurous acids were studied. In addition, p-creosol and vanillyl alcohol were introduced to check whether it is possible to convert polysaccharides (such as hemicelluloses) into monosaccharides during the sulfurous acid treatment. The results showed that the decomposition of MGPα is much slower in H2SO3 than in HCl and H2SO4. The ligninsulfonic acid resulting from the lignin sulfonation reaction can be expected to improve the efficiency of hydrolysis of polysaccharides into monosaccharides during sulfurous acid treatment. Moreover, a higher actual yield of glucose was obtained in this case than in the other two acids. . [ABSTRACT FROM AUTHOR]

The leaching process is an important component in hydrometallurgy. A predictive model of the leaching rate lays the foundation for soft measurement and process optimization, and data collection is the key in such a modeling effort. However, because of the complexity and harshness of leaching process, data can only be collected sparsely, which results in data deficiency in the modeling process. Therefore, data imputation before modeling seems to be extremely significant. In this paper, expectation maximization imputation based on the Gaussian mixture model (GMM-EM) and multiple imputation (MI) are respectively applied to perform missing data imputation for leaching process under different data loss rates and data loss patterns, and then the imputation performances are evaluated. Simulation experiment results have shown that GMM-EM and MI both have advantages with regard to data imputation. Therefore, MI based on GMM (GMM-MI), which combines the advantages of GMM and MI, is proposed in this paper. The effectiveness of GMM-MI is verified by a series of simulations. [ABSTRACT FROM AUTHOR]

Carbon Capture and Storage (CCS) has been highlighted as a potential method to enable the continued use of fossil-fuelled power stations through the abatement of carbon dioxide (CO2). A complete CCS cycle requires safe, reliable and cost effective solutions for the transmission of CO2from the capturing facility to the location of permanent storage. This publication presents a detailed review of the integrity risks posed to dense-phase CO2pipelines in the form of internal corrosion. To begin, the current worldwide experience in handling dense-phase CO2and the anthropogenic stream compositions expected from the different combustion techniques currently available are discussed. The anticipated compositions are then related to a number of tentative CO2stream compositions available in open literature proposed by research institutes and pipeline operators. In subsequent sections, early laboratory and field corrosion experience relating to natural dense-phase CO2transport for the purposes of enhanced oil recovery (EOR) are summarised along with more recent research efforts which focus on identifying the role of anthropogenic impurities in the degradation processes. For each system impurity, the reaction rates, mechanisms and corrosion product composition/morphology expected at the steel surfaces are discussed, as well as each component’s ability to influence the critical water content required to initiate corrosion. Potential bulk phase reactions between multiple impurities are also evaluated in an attempt to help understand how the impurity content may evolve along a long-distance pipeline. The likelihood of stress-corrosion cracking and hydrogen-induced cracking is discussed and the various corrosion mitigation techniques which exist to control degradation to acceptable levels are reviewed. Based on the current research performed in the context of impure dense-phase CO2corrosion, issues associated with performing laboratory experiments to replicate field conditions and the challenges such limitations present in terms of defining the safe operating window for CO2transport are considered. [ABSTRACT FROM PUBLISHER]

The mathematical modeling of the conversion of hemicelluloses of wheat straw and sugar beet pulp into monosaccharides using diluted sulphurous acid (0.59 and 1.18% wt) at high temperatures was performed. Kinetic equation, activation energy, pre-exponential factor and reaction order of the acid catalyst were determined. It was shown that agreement between the experimental data and kinetic model is good. It was proved that the process proceeds in the kinetic region and the entire array of measurements of the yield of monosaccharides satisfactorily described by the model with the minimum number of steps. The model predicts a decrease of duration of the process and increase of monosaccharides concentration in hydrolysates of lignocellulosic feedstock with temperature increase. [ABSTRACT FROM AUTHOR]

The gas- and liquid-phase chemistry of nitrogen and sulfur species under pressurized conditions is of high importance to the design and performance of the pressurized flue gas systems in carbon capture and storage (CCS) schemes. Yet, the available description of this chemistry is complex and difficult to apply in design studies for removal of NOx and SOx during the compression. This work proposes a reduced mechanism for engineering calculations of pressurized flue gas systems, a mechanism that is able to describe the relevant gas- and liquid-phase chemistry as well as the S/N-product distribution. The reduced mechanism is derived by identifying the rate-limiting reactions using sensitivity analysis. The performance of the mechanism subsets are compared with results of a detailed mechanism. The identified rate-limiting reactions for the formation of key products form the basis for two different types of reduced mechanisms. The sets include one general reduced mechanism (valid for all pH conditions) and sets of pH-specific mechanisms. The general reduced mechanism and the pH-specific mechanisms perform satisfactorily compared to the detailed mechanism under different pH conditions. The results show that depending on the purpose of the modeling, whether it is to predict the pollutant removal (where sulfurous acid and nitrogen acids are mainly important) or capture the liquid composition, for which the N-S chemistry products are also important, different levels of simplification can be made. The number of reactions is reduced from 34 reactions (39 species) in the detailed mechanism to 12 reactions (20 species) in the general reduced mechanism and 7-8 (14-17 species) in the pH-specific mechanisms. [ABSTRACT FROM AUTHOR]

Six stone types with differences in composition and texture were exposed to four strong acid atmospheres formed from different acids: H 2 SO 3 , HNO 3 , and two mixed solution with different proportions of H 2 SO 3 and HNO 3 . The changes on the surface were assessed by weight, colour, roughness and microscopic observation. Exposure to the atmosphere formed by HNO 3 hardly affected the stone, whereas these formed from H 2 SO 3 produced evident alterations. Depending on the HNO 3 /H 2 SO 3 ratio, the nitrogen compounds may react with the stone and precipitate nitrates or nitrites or may only act as a catalyser of SO 2 and enhance the formation of gypsum. Colour and roughness are efficient non-destructive approaches to evaluating the damage produced by acid atmospheres. [ABSTRACT FROM AUTHOR]

Background: Benincasa hispida (BH) and Carissa congesta (CC) are regarded as ethnopharmacological imperative plants in Asian countries. Objective: Phytochemical screening of the extracts has shown the presence of steroids, flavonoids, saponins, glycosides, tannins, phenolic compounds, fixed oils, and fats in the BH and CC extracts. The presence of lupeol has been reported previously by us using high-performance thin-layer chromatography and high-performance liquid chromatography. Materials and Methods: Present research studies encompasses identification of chemical constituents in BH seeds and CC roots petroleum ether extracts by hyphenated technique such as gas chromatography-mass spectroscopy (MS) which when coupled gives a clear insight of constituents. Results: The components were identified by matching mass spectra with MS libraries. There were 13 and 10 different compounds analyzed from CC and BH, respectively. The components present were Pentanoic acid, 5-hydroxy, 2,4-butylphenyl; n-Hexadecanoic acid (Palmitic acid); Sulfurous acid, 2-ethylhexylhepatdecyl ester; n-Tridecane; 6-methyltridecane; (9E, 12E)-9,12-Octadecadienyl chloride, Hexadecanoic acid, 3-(trimethylsilyl)-oxy] propyl ester; 9,12-Octadecadenoic acid, 2 hydroxy-1-(hyroxymethylethyl) ester; 9,12-Octadecadienoic acid, 2,3 dihydroxypropyl ester; n-Propyl-9,12-Octadecadienoate, Lupeol; Taraxasterol; 6a, 14a-Methanopicene, perhydro-12,4a, 61a, 9,9,12a-hepatmethyl-10-hydoxy and 9-Octadecene; 2-Isoprpenyl-5-methyl-6-hepten-1-ol; n-Hexadecanoic acid, 2-hyroxy-1-(hydroxymethyl) ethyl ether; Butyl-9,12-Octadecadieonate; Friedoolean-8-en-3-one; friedours-7-en-3-one; 13,27-Cyclosuran-3-one; Stigmaste-7,25-dien-3-ol (3β, 5α); Stigmasta-7,16-dien-3-ol; chrondrillasterol in BH seeds and CC roots extracts respectively. Conclusion: Eluted components from the extracts could provide further researchers to work with various pharmacological activities related models and studies. [ABSTRACT FROM AUTHOR]

Effective diffusion coefficient ( D-value) is an important parameter for the extraction process. In this study, a cylindrical model to estimate the D-value of betanin extraction from red beet roots was developed. The influence of extraction temperature, pH, cylindrical thickness and type of acids on the D-value was also investigated. The optimal parameters of betanin extraction were 30°C, pH 4.0 adjusted with sulfurous acid or acetic acid. D-values under the above conditions were 18.95×10−11 m2/s and 17.87×10−11 m2/s, respectively. The result showed that D-value elevated with the increase of cylindrical thickness, which was consistent with earlier conclusion from spherical model. The modeling may be useful for the investigation into extraction process and practical application. [ABSTRACT FROM AUTHOR]

Quantification of soil organic carbon (SOC) is an important element in the assessment of the carbon sequestration potential of soils in tree-based intercropping (TBI) systems. The organic carbon (OC) concentrations of soils in TBI systems often differ from those in conventional agricultural systems due to the additional C inputs from litter fall and roots. However, the presence of soil inorganic carbon (SIC) can confound the measurements of SOC. This study compared three methods of measuring SOC: (i) measurement of the total soil C (TC) in one subsample and, after treatment in a muffle furnace (575 °C) for 24 h, measurement of SIC in another subsample; (ii) SOC measured after fumigation with 12 M hydrochloric acid (HCl) to remove SIC; and (iii) SOC measured after digestion with 0.73 M H2SO3to remove SIC. The TC, SOC, and SIC concentrations were determined by combustion. A correction factor was applied to express SIC and SOC concentrations on an original, untreated soil basis. Measurement of SOC by the muffle furnace method resulted in the greatest SOC concentrations forPopulusspp. (hybrid poplar) for samples from two of the three depths (0–10 and 20–40 cm). Measurement of SOC by the HCl fumigation and H2SO3digestion methods were highly correlated, suggesting complete removal of SIC with minimal oxidation of SOC. These results have implications for the method of measuring SOC in calcareous soils under coniferous and deciduous tree species to a depth of 40 cm. [ABSTRACT FROM PUBLISHER]

Nitrosomonas europaea , an ammonia oxidizing bacterium, was chosen as a research model to study the alteration of cell membrane in the presence of sulfurous acid and biodegradation of acetochlor. Significant changes of the outer cell membrane were observed in the presence of sulfurous acid using scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM). The fluorescence polarization has shown a significant decrease in membrane fluidity and the increase of permeability of cell membrane. Lysozyme experiment show the cell becomes easily influenced by substance in medium. Inductively Coupled Plasma–Mass Spectrometry (ICP–MS) measurements show considerable amount of Ca 2+ and Mg 2+ in the supernatant from the sulfurous acid exposed cells. Sulfurous acid treatment enhanced the ability of N. europaea to degrade acetochlor. On this basis, it can be concluded that the increased cell permeability is favor for the absorbability of nutrition. As a result, N. europaea grows faster and the biodegradation efficiency was improved. [ABSTRACT FROM AUTHOR]

Solvent extraction of Fe(III) from chloride solution by using a mixture of D2EHPA (Di-(2-ethylhexyl)-phosphoric acid) and TBP (Tri-butyl phosphate) and the reductive stripping of Fe(III) from the loaded organic were investigated. Quantitative extraction of Fe(III) from the solution (Fe concentration = 90 g/L) was accomplished in two cross-current extraction stages by using the mixture of D2EHPA and TBP. In order to facilitate the stripping efficiency, a reductive stripping method was employed by using H2SO3 or Na2SO3 as a reducing agent. The addition of H2SO4 into reducing agents led to improvement in the stripping efficiency while high concentration acid would suppress it. Both of the mixtures of H2SO4 + H2SO3 and H2SO4 + Na2SO3 showed good efficiency for the stripping of Fe(III), while the latter was recommended as the stripping solution based on the economics and experimental condition. [ABSTRACT FROM AUTHOR]

ABSTRACT Giant water bug ( Lethocerus indicus Lep. and Serv.) is an edible fresh water insect used for flavouring some types of Thai chili pastes and fish sauce products due to its distinctive aroma. Aroma-active compounds in the scent glands of male giant water bugs were determined by gas chromatography-olfactometry and aroma extract dilution analysis. Two trace odorants with sulfurous/catty-like and ripe guava-like odours were detected with flavour dilution factors of 729 and 9, respectively. Additional enrichment steps consisting of ultrasonic direct solvent extraction/solvent-assisted flavour evaporation combined with mercurated agarose gel chromatography enabled the identification of the compounds 3-sulfanylhexyl acetate and 3-sulfanyl-1-hexanol (tentatively identified). These sulfur-containing compounds were identified for the first time in the scent glands of male giant water bug and are thought to contribute important characteristic odours to the overall aroma of giant water bug. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] The relationship between poultry NMVOCs and odor was determined using chemometrics. [•] A small set of NMVOCs provided strong predictions of odor. [•] High litter moisture favored sulfurous odorants but did not affect odor concentration. [•] High bird density favored non-sulfurous odorants and slightly increased odor. [•] The dominant odorants were primarily associated with the litter, manure and feed. [ABSTRACT FROM AUTHOR]

This study focuses on sulphurous and carbonaceous aerosol, the major constituents of particulate matter in the lowermost stratosphere (LMS), based on in situ measurements from 1999 to 2008. Aerosol particles in the size range of 0.08-2 mm were collected monthly during intercontinental flights with the CARIBIC passenger aircraft, presenting the first long-term study on carbonaceous aerosol in the LMS. Elemental concentrations were derived via subsequent laboratory-based ion beam analysis. The stoichiometry indicates that the sulphurous fraction is sulphate, while an O/C ratio of 0.2 indicates that the carbonaceous aerosol is organic. The concentration of the carbonaceous component corresponded on average to approximately 25% of that of the sulphurous, and could not be explained by forest fires or biomass burning, since the average mass ratio of Fe to K was 16 times higher than typical ratios in effluents from biomass burning. The data reveal increasing concentrations of particulate sulphur and carbon with a doubling of particulate sulphur from 1999 to 2008 in the northern hemisphere LMS. Periods of elevated concentrations of particulate sulphur in the LMS are linked to downward transport of aerosol from higher altitudes, using ozone as a tracer for stratospheric air. Tropical volcanic eruptions penetrating the tropical tropopause are identified as the likely cause of the particulate sulphur and carbon increase in the LMS, where entrainment of lower tropospheric air into volcanic jets and plumes could be the cause of the carbon increase. [ABSTRACT FROM AUTHOR]

Highlights: [•] Experiments were performed in a 300W reactor with continuous circulation. [•] Sulfurous and sulfur-free kerosene were used directly as fuel. [•] Ilmenite oxygen carrier (Norwegian rock ilmenite) was tested. [•] Combustion experiments were performed for 50h (sulfur-free) and 30h (sulphurous), respectively. [•] A significant and lasting improvement in the oxygen carrier’s reactivity was achieved by using sulfurous kerosene. [ABSTRACT FROM AUTHOR]

The relative abundances of DNA of Mycosphaerella graminicola and Phaeosphaeria nodorum in archived wheat samples are closely correlated with UK anthropogenic emissions of oxidized sulphur over the last 160 years. To test whether this could be a causal relationship, possible modes of action of sulphur on the two fungi were examined. Mycelial growth of the two fungi in solutions of sulphurous acid was similar. Sulphurous acid at p H 4 reduced percentage germination of P. nodorum conidia more strongly than M. graminicola conidia. In spray inoculations of wheat cv. Squarehead's Master, Cappelle Desprez and Riband with water or sulphurous acid (p H 4), the ratio of leaves infected by P. nodorum to leaves infected by M. graminicola was increased by factors of 2·5, 2·1 and 0·6, respectively at pH 4. The same three cultivars of wheat were grown in sand and vermiculite and fertilized with nutrient solution containing 2·5 or 0·5 m m sulphate. Both pathogens infected less frequently at 2·5 m m sulphate, by a factor of about 2. The severity of infection by M. graminicola was reduced on all three cultivars by a factor of about 4·5 at 2·5 m m sulphate, but severity of P. nodorum was reduced only by a factor of about 2. Both elevated free sulphate concentrations in soil and sulphite in rainwater could therefore increase the prevalence of P. nodorum relative to M. graminicola, which is consistent with the historical changes in abundance. [ABSTRACT FROM AUTHOR]

Abstract: In the gasification of an aquatic biomass with He/CO2/O2, the effects of the concentration of CO2 and O2 in the gasifying agent and the feeding rate on the gasification behavior were investigated using a downdraft fixed-bed gasifier at 900°C. Using CO2/O2 as the gasifying agent led to an increase in the conversion to gas and the syngas (CO+H2) content because the gasification of char with CO2 (C+CO2 →2CO) and the decomposition of tarry compounds were promoted. Increasing CO2 content led to the increase in the conversion to gas and CO content and the decrease in the H2 content. With increasing O2 content, contents of CO and H2 increased while the conversions to gas remained almost constant. Especially with CO2/O2 =45/55vol.%, the conversion to gas was 94.0C-mol% and the syngas content exhibited a maximum value of 69.7vol.%. As the feeding rate was decreased, contents of CO and H2 decreased while the conversion to gas remained almost constant. The nitrogen atoms in the feedstock were mainly converted to form N2. H2S and COS were the main sulfurous gases. The sulfur content in the char was much higher than that in the feedstock. [Copyright &y& Elsevier]

The potential of sulfurous acid prehydrolysis followed by chemical pulping was examined at the laboratory scale using radiata pine. The residue obtained by sulfurous acid prehydrolysis with base addition was sufficiently delignified in a subsequent soda pulping stage, while the delignification of the residue was completely insufficient in subsequent kraft pulping. The residues prepared by prehydrolyses of hydrochloric and sulfuric acids were not delignified sufficiently regardless of the pulping method. The yield of hemicellulose-derived monosaccharides was about 90% on a theoretical basis in the optimal sulfurous acid prehydrolysis. In subsequent soda pulping under various conditions, pulps with kappa number 21 to 34, pulp yield 37 to 41%, and high cellulose content could be prepared from the residue obtained by sulfurous acid prehydrolysis with base addition. It was suggested from these results that sulfurous acid prehydrolysis with base addition in combination with subsequent soda pulping is an effective method for the utilization of wood hemicelluloses. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of oxygen enrichment on acid gas (H2S and CO2) combustion was examined. [•] Increase in the percentage of oxygen enrichment increased the rate of SO2 production. [•] CO2-laden acid gas had faster rates of reactants decomposition/products evolution. [•] Existence of CO in the reaction pool was evident on CO2 role as an oxidizer provider. [•] Presence of CO enhanced the rate of other sulfurous compounds formation, CS2 and COS. [ABSTRACT FROM AUTHOR]

Abstract: This article describes the results of an investigation about the failure of spiral finned tube on a newly designed and retrofitted low pressure economizer in a 300MW pulverized-coal-fired power plant. In order to find out the failure causes and to suggest preventive measures, phase compositions and macrostructure of the tube metal surface were investigated by X-Ray Diffraction and Scanning Electron Microscope equipped with energy dispersive X-Ray spectroscopy micro-analysis. The results show that the failure was principally owing to comprehensive multiphase erosion, an interaction of the fly ash wearing, flue gas washing and sulfurous acid corrosion. Recommendations are given to minimize such failures. [Copyright &y& Elsevier]

Abstract: This work investigated the characteristics and mechanisms of hydrogen sulfide adsorption by ferric and alum water treatment residuals (FARs) in solution. The results indicated that FARs had a high hydrogen sulfide adsorption capacity. pH 7 rather than higher pH (e.g. pH 8–10) was favorable for hydrogen sulfide removal. The Yan model fitted the breakthrough curves better than the Thomas model under varied pH values and concentrations. The Brunauer–Emmett–Teller surface area and the total pore volume of the FARs decreased after the adsorption of hydrogen sulfide. In particular, the volume of pores with a radius of 3–5nm decreased, while the volume of pores with a radius of 2nm increased. Therefore, it was inferred that new adsorption sites were generated during the adsorption process. The pH of the FARs increased greatly after adsorption. Moreover, differential scanning calorimetry analysis indicated that elemental sulfur was present in the FARs, while the derivative thermal gravimetry curves indicated the presence of sulfuric acid and sulfurous acid. These results indicated that both oxidization and ligand exchange contribute to the removal of hydrogen sulfide by FARs. Under anaerobic conditions, the maximum amount of hydrogen sulfide released was approximately 0.026mgg−1, which was less than 0.19% of the total amount adsorbed by the FARs. The hydrogen sulfide that was released may be re-adsorbed by the FARs and transformed into more stable mineral forms. Therefore, FARs are an excellent adsorbent for hydrogen sulfide. [Copyright &y& Elsevier]

Acidic tropospheric aerosols contain inorganic speciessuch assulfurous acid (H2SO3). As the main alkalinespecies, ammonia (NH3) plays an important role in the heterogeneousneutralization of these acidic aerosols. An aerosol flow-tube apparatuswas used to obtain simultaneous optical and size distribution measurementsusing FTIR and SMPS measurements, respectively, as a function of relativehumidity and aerosol chemical composition. A novel chemiluminescenceapparatus was also used to measure ammonium ion concentration [NH4+]. The interactions between ammonia and hydratedsulfur dioxide (SO2·H2O) were studied atdifferent humidities and concentrations. SO2·H2O is an important species as it represents the first intermediatein the overall atmospheric oxidation process of sulfur dioxide tosulfuric acid (H2SO4). This complex was producedwithin gaseous, aqueous, and aerosol SO2systems. The additionof ammonia gave mainly hydrogen sulfite (SHO3–) tautomers and disulfite ions (S2O52–). These species were prevalent at high humidities enhancing theaqueous nature of sulfur(IV) species. Their weak acidity is evidentdue to the low [NH4+] produced. Size distributionsobtained correlated well with the various stages of particulate compositionaldevelopment. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the work was the analysis of the phenomena occurring during glycerol dehydration in the presence of sulfated zirconia used as solid acid catalysts; the attention was focused on catalyst deactivation. A close correlation between the sulfate content and catalytic behavior was found. In addition to the accumulation of carbon residues on the catalyst surface, there were other phenomena contributing to catalyst deactivation: (i) the self-reduction of sulfuric into sulfurous groups – an event which occurred, however, only in samples with the higher S content under anaerobic conditions – and (ii) the leaching of S from catalysts, due to the hydrolysis of sulfate groups and the formation of volatile esters. These findings are of general interest in relation to both the transformation of glycerol into acrolein by means of gas-phase dehydration and the use of sulfated zirconia catalysts for high-temperature, acid-catalyzed reactions. [Copyright &y& Elsevier]

Physical and chemical hypoxia have been widely used in the study of hypoxic injury; however, both of these hypoxia models have their own limitations. Physical hypoxia is usually difficult to control and maintain. Chemical hypoxia, which is usually induced by chemical hypoxia-mimicking agents, such as CoCl, may result in heavy metal toxicity or impose security threats. To develop a more suitable hypoxia model, we focused on sodium sulfite (NaSO) and evaluated its ability to remove dissolved oxygen in aqueous solutions. Our results showed that sodium sulfite successfully induced hypoxic conditions. The degree of hypoxia and the guarantee period of the sodium sulfite solution could be easily controlled by the concentration of soluble sodium sulfite. In addition, we used sodium sulfite to create a hypoxia model in Caenorhabditis elegans. Similar to physical hypoxia, the sodium sulfite solutions induced hypoxia-related death in the worms and led to morphologic cell defects and C. elegans hypoxia inducible factor 1 stabilization. Taken together, our data show that sodium sulfite is a potential hypoxia inducer that mimics hypoxic stress in C. elegans. [ABSTRACT FROM AUTHOR]

Abstract: High purity single crystalline trigonal selenium (t-Se) with different morphologies (wires, rods, flowerlike, and hollow spheres) have been synthesized under hydrothermal conditions through simple one-step at lower temperature (120°C) using in situ generated sulphurous acid as a new reducing agent. It is noted that the experimental parameters such as reaction duration, temperature and surfactants have an effective and important influence on the formation of different morphologies. The phase analysis, purity, morphology and optical properties of the as obtained products have been characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectroscopy, respectively. A possible reaction scheme as well as growth mechanism has been proposed for the formation of t-Se nanowires. [Copyright &y& Elsevier]

We investigated the distribution of vanadium(IV) during extraction from model and actual technological sulfurous solutions by the organophosphorous acids di(2-ethylhexyl)phosphoric acid (DEHPA) and di(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) using various solvents. We determined the most effective organic and organomineral mixtures for the extraction of vanadium(IV) from model and technological solutions of aqueous leach of used vanadium catalysts. [ABSTRACT FROM AUTHOR]

Abstract: Irradiating fresh meat, even at low doses, can result in off-odors and flavors which have been described as rotten egg, bloody, fishy, barbecued corn, burnt, sulfur, metallic, alcohol or acetic acid. The odors vary with the type of meat, temperature during irradiation, oxygen exposure during and/or after the irradiation process, packaging and presence of antioxidative substances. Irradiation can induce formation of isooctane-soluble carbonyl compounds in the lipid fraction and low molecular weight, acid-soluble carbonyls in the protein fraction of meat. Increasing irradiation dose increases these compounds however, cooking reduces them. Among the volatile components, 1-heptene and 1-nonene are influenced most by irradiation dose, and aldehydes (propanal, pentanal, hexanal) are influenced most by packaging type (aerobic vs vacuum). Sulfur-containing volatiles formed from sulfur-containing compounds (primarily amino acids) also contribute to irradiation odor. Dimethyltrisulfide is one of the most potent off-odor compounds, contributing fishy, putrid odors, followed by bismethylthiomethane (sulfurous). Reducing the temperature during the irradiation process reduces the effects on odor/flavor because free radical generation and dispersion are reduced. Ultimately, radiolysis of water into free radical species (yph name="rad" />H, H30+, ) may be the initiators of both lipid oxidation breakdown products and sulfur-containing volatiles responsible for irradiation odor. Methods to decrease the detrimental effects of irradiation include oxygen exclusion (vacuum packaging), replacement with inert gases (nitrogen), addition of protective agents (antioxidants), and post-irradiation storage to allow flavor to return to near-normal levels (re-packaging or double packaging in oxygen permeable film). [Copyright &y& Elsevier]

Reaction of aryl-and trifluoromethanesulfonic acids N,N-dichloroamides with tribromoethylene led to the formation of a mixture of N-(2,2-dibromo-2-chloroethylidene)-and N-(2,2,2-tribromoethylidene)amides of the corresponding sulfonic acids. The azomethines ratio is governed by the reaction temperature. [ABSTRACT FROM AUTHOR]

Determines the total organic carbon (TOC) in aquifer solids after carbonate removal by sulfurous acid. Methods of TOC determination; Quantification of carbon; Accuracy of TOC determinations; Measurement of TOC contents.

In this study, the modification of the catalyst in a model system imitating the oxidation of sulfurous-alkali drainage by molecular oxygen is investigated. Change in the catalyst structure can be another cause of the appearance of the negative effect of nonadditivity in the system. [ABSTRACT FROM AUTHOR]

The article presents classroom activities that demonstrate high school students on how the Relative Acid-Base Strength chart can be applied in predicting the most likely products from a given set of chemical reactants. Under the procedure, two different chemical reactions that are both conducted in zipper-style plastic storage bags were presented. In addition to this, students also employed Brønsted-Lowry Theory to predict the identities and formulas of possible products. Findings have shown that reaction one has produced sulfuric acid, while reaction two has produced sulfurous acid.

A rapid and simple technique is proposed for methanol concentration detection using a PMMA (Polymethyl-Methacrylate) microfluidic chip patterned using a commercially available CO2 laser scriber. In the proposed device, methanol and methanol oxidase (MOX) are injected into a three-dimensional circular chamber and are mixed via a vortex stirring effect. The mixture is heated to prompt the formation of formaldehyde and is flowed into a rectangular chamber, to which fuchsin-sulphurous acid is then added. Finally, the microchip is transferred to a UV spectrophotometer for methanol detection purposes. The experimental results show that a correlation coefficient of R2 = 0.9940 is obtained when plotting the optical density against the methanol concentration for samples and an accuracy as high as 93.1% are compared with the determined by the high quality gas chromatography with concentrations in the range of 2 ∼ 100 ppm. The methanol concentrations of four commercial red wines are successfully detected using the developed device. Overall, the results show that the proposed device provides a rapid and accurate means of detecting the methanol concentration for a variety of applications in the alcoholic beverage inspection and control field. [ABSTRACT FROM AUTHOR]