An FT-IR study of adsorption of sulfur dioxide on alpha- and gamma-alumina

In the Claus process hydrogen sulfide reacts to elemental sulfur. Because the Claus reaction is thermodynamically limited, sulfur compounds are still present in Claus tailgas. To avoid air pollution, the tailgas has to be treated.Alfa- and gamma-alumina are being used either as a catalyst or as a support for an active component in the Claus process and some tailgas treatment processes. In order to elucidate the mechanism of the Claus reaction, the adsorption of sulfur dioxide on both of the above aluminas was investigated using Fourier transform infrared spectroscopy.Different adsorbed species displaying a different heat of adsorption were detected. A broad band near 3500 cm^–1 is associated with the basic hydroxyl groups. This band is assigned to a hydrogen bond between the surface of alumina and a bisulfite species. As bisulfite species are reactive towards hydrogen sulfide, we assume that bisulfite species are active intermediates on alumina in the Claus reaction.     

A Novel Fluorescence Probe for the Reversible Detection of Bisulfite and Hydrogen Peroxide Pair in Vitro and in Vivo

The detection of changes in the reactive oxygen species (ROS)/reactive sulfur species (RSS) couple is important for studying the cellular redox state. Herein, we developed a 1,8-naphthalimide-based fluorescence probe ( NI ) for the reversible detection of bisulfite (HSO₃⁻) and hydrogen peroxide (H₂O₂) in vitro and in vivo. NI has been designed with a reactive ethylene unit which specifically reacts with HSO₃⁻ by a Michael addition reaction mechanism, resulting in the quenching of yellow fluorescence at 580 nm and the appearing of green fluorescence at 510 nm upon excitation at 500 nm and 430 nm, respectively. The addition product ( NI−HSO₃ ) could be specifically oxidized to form the original C=C bond of NI , recovering the fluorescence emission and color. The detection limits of NI for HSO₃⁻ and NI−HSO₃ for H₂O₂ were calculated to be 2.05 μM and 4.23 μM, respectively. The reversible fluorescence response of NI towards HSO₃⁻/H₂O₂ couple can be repeated for at least five times. NI is reliable at a broad pH range (pH 3.0–11.5) and features outstanding selectivity, which enabled its practical applications in biological and food samples. Monitoring the reversible and dynamic inter-conversion between HSO₃⁻ and H₂O₂ in vitro and in vivo has been verified by fluorescence imaging in live HeLa cells, adult zebrafish and nude mice. Moreover, NI has been successfully applied to detect of HSO₃⁻ levels in food samples.     

Sodium Bisulfite as an Efficient and Inexpensive Catalyst for the One-pot Synthesis of 2,4,5-Triaryl-1<Emphasis Type="Italic">H</Emphasis>-imidazoles from Benzil or Benzoin and Aromatic Aldehydes

Summary. 2,4,5-Triaryl-1H-imidazoles were efficiently synthesized from benzoin or benzil, ammonium acetate, and aromatic or heteroaromatic aldehydes in the presence of sodium bisulfite as catalyst. The present protocol offers significant improvements for the synthesis of 2,4,5-triaryl-1H-imidazoles with regard to yield of products, simplicity in operation, and cheap catalyst.     

亚硫酸氢钠-过氧化氢超微弱化学发光体系用于核黄素检测

亚硫酸氢钠(Na HSO3)和过氧化氢(H2O2)反应可产生微弱的化学发光。核黄素对亚硫酸氢钠和过氧化氢的化学发光有极大的增强作用,且化学发光强度在0.02~2.0μg/m L范围内与核黄素浓度呈良好的线性关系。据此,建立了核黄素的高灵敏化学发光分析方法,方法检出限为0.007μg/m L,相对标准偏差(n=11)不大于1.6%。利用荧光光谱、化学发光谱对核黄素增强Na HSO3-H2O2体系化学发光的机理进行探讨,为该体系的应用研究提供了新思路。     

亚硫酸氢钠溶液稳定性的探讨

从溶液的酸度、空气及光照、温度等因素对亚硫酸氢钠溶液的稳定性及滴定反应进行实验探讨,选择三乙醇胺(TEA)、甲醛、二乙胺四乙酸二钠(EDTA-2Na)、盐酸羟胺四种常用的螯合剂或强还原剂进行试验,结果表明EDTA-2Na作为溶液的稳定剂效果最好,其次是甲醛,最后是盐酸羟胺。TEA因为其强碱性会降低溶液的稳定性而不宜作为稳定剂。     

Studies on sulfinatodehalogenation: The addition of polyfluoroalkyl iodides to olefins promoted by sodium bisulfite and sodium sulfite

The reaction of polyfluoroalkyl iodides with alkenes or 4-pentenoic acid promoted by sodium bisulfite or sodium sulfite in DMF aqueous solution was realized. The reaction of alkenes gave corresponding adducts, while γ-lactones were obtained in the case of 4-pentenoic acid in good yields.     

The second chemiluminescence emission of luminol-periodate-menadione sodium bisulfite system and its analytical application

In this paper, a new chemiluminescence phenomenon described as the second chemiluminescence emission was observed when menadione sodium bisulfite was injected into a reaction mixture of luminol and potassium periodate, in which luminol was oxidized by excess amount of potassium periodate for about 24 h. The mechanism of the second chemiluminescence emission was proposed based a series of experiments. Moreover, our experiment discovered that the second chemiluminescence intensity was a linear function of the concentration of menadione sodium bisulfite in the range of 2 × 10⁻⁹ to 4 × 10⁻⁵ g L⁻¹. Based on this phenomenon, a new flow-injection method for the determination of menadione sodium bisulfite has been established.     

Novel Coumarin-based Fluorescent Probe for Selective Detection of Bisulfite Anion in Water

Coumarins and its analogues have been widely used as chromophore in design of fluorescent probe, while less coumarin‐based fluorescent probe was reported for detection of anion in water. In this article, coumarin‐based fluorescent probes with salicylaldehyde functionality as recognition unit have been developed for selective detection of bisulfite anions in water. Four novel fluorescent probes were synthesized from 4‐haloresorcinol in three steps. The chemoprobe exhibited selective response to bisulfite over other anions. Moreover, the detection mechanism was studied. Upon bisulfite added, the fluorescent intensity of the probes was enhanced highly due to the nucleophilic addition reaction of formyl group with bisulfite anion.     

Study on the electrochemiluminescent behavior of menadione sodium bisulfite in presence of luminol

Menadione sodium bisulfite (MSB) is a stable water-soluble derivative of Vitamin K₃, which is found to be able to enhance the ECL of luminol at potential of 0.88 V in phosphate buffer solution. The conditions for the enhanced ECL, such as the selection of the type of buffer solution, applied potential mode, scanning rate, the effect of pH and concentration of luminol have been investigated in detail in this paper. Under the optimum conditions, the enhanced ECL intensity is linear with the concentration of MSB over a wide range, the detection limit for MSB is 3.0 × 10⁻⁷ mol/L. The proposed method has been applied to determine the MSB in the commercial injection samples. A possible mechanism for the enhanced ECL of luminol by MSB has also been proposed.