Relevant bibliographies by topics / Sodium dithionite

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Academic literature on the topic 'Sodium dithionite'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Sodium dithionite"

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Zhang, Xiao-Nan. "Sodium Dithionite." Synlett 2011, no. 14 (August 23, 2011): 2104. http://dx.doi.org/10.1055/s-0029-1261191.

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Zhang, Xiao-Nan. "Sodium Dithionite." Synlett 2011, no. 13 (July 21, 2011): 1947–48. http://dx.doi.org/10.1055/s-0030-1260969.

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Cho, Kyung-Rae. "The Effect of Sodium dithionite in Dyeing with Indigo Pulverata Levis." Textile Coloration and Finishing 27, no. 2 (June 27, 2015): 155–63. http://dx.doi.org/10.5764/tcf.2015.27.2.155.

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Vázquez, Gonzalo, Estrella Alvarez, Rocío Varela, Angeles Cancela, and José M. Navaza. "Density and Viscosity of Aqueous Solutions of Sodium Dithionite, Sodium Hydroxide, Sodium Dithionite + Sucrose, and Sodium Dithionite + Sodium Hydroxide + Sucrose from 25 °C to 40 °C." Journal of Chemical & Engineering Data 41, no. 2 (January 1996): 244–48. http://dx.doi.org/10.1021/je950243k.

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Flaherty, B., and J. M. Bather. "Thermal decomposition of sodium dithionite." Journal of Applied Chemistry and Biotechnology 21, no. 8 (April 25, 2007): 236–37. http://dx.doi.org/10.1002/jctb.5020210805.

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BROADBENT, A. D., and F. PÉTER. "Polarographic Analysis of Sodium Dithionite." Journal of the Society of Dyers and Colourists 82, no. 7 (October 22, 2008): 264–67. http://dx.doi.org/10.1111/j.1478-4408.1966.tb02722.x.

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Ilanidis, Dimitrios, Stefan Stagge, Björn Alriksson, and Leif J. Jönsson. "Factors Affecting Detoxification of Softwood Enzymatic Hydrolysates Using Sodium Dithionite." Processes 9, no. 5 (May 18, 2021): 887. http://dx.doi.org/10.3390/pr9050887.

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Conditioning of lignocellulosic hydrolysates with sulfur oxyanions, such as dithionite, is one of the most potent methods to improve the fermentability by counteracting effects of inhibitory by-products generated during hydrothermal pretreatment under acidic conditions. The effects of pH, treatment temperature, and dithionite dosage were explored in experiments with softwood hydrolysates, sodium dithionite, and Saccharomyces cerevisiae yeast. Treatments with dithionite at pH 5.5 or 8.5 gave similar results with regard to ethanol productivity and yield on initial glucose, and both were always at least ~20% higher than for treatment at pH 2.5. Experiments in the dithionite concentration range 5.0–12.5 mM and the temperature range 23–110 °C indicated that treatment at around 75 °C and using intermediate dithionite dosage was the best option (p ≤ 0.05). The investigation indicates that selection of the optimal temperature and dithionite dosage offers great benefits for the efficient fermentation of hydrolysates from lignin-rich biomass, such as softwood residues.
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Hubert, Cathy, and Bernard Garrigues. "Influence des ultrasons sur la diastéréosélectivité. Synthèse d'imidazolidine-4-one chirales." Canadian Journal of Chemistry 76, no. 2 (February 1, 1998): 234–37. http://dx.doi.org/10.1139/v97-232.

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A three-step synthesis of imidazolidine-4-one has been realized. Sodium dithionite was a very efficient reagent for the last step, the reduction of a ketone. The reaction is slow under the normal conditions of heating and its diastereoselectivity is poor. Under the influence of ultrasound, the selectivity and the yield are very good. The use of sodium dithionite makes it possible to work in water and to avoid the use of hydrides.Key words: sodium dithionite, ultrasound, imidazolidine-4-one.
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Jiang, Yu, Yangmei Chen, Qitang Wu, and Zebin Wei. "Fiber structures and properties of eucalyptus kraft pulp via different bleaching methods." Nordic Pulp & Paper Research Journal 34, no. 3 (September 25, 2019): 280–88. http://dx.doi.org/10.1515/npprj-2019-0030.

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Abstract The fiber morphology, the content of hydrogen bonds (HBs) of different models, cellulose crystalline structure, water retention value (WRV), and strength properties of eucalyptus pulp bleached by different bleaching methods (hydrogen peroxide bleaching and sodium dithionite bleaching) were investigated. The results of fourier transform infrared spectrometer (FTIR) showed that the content of intramolecular hydrogen bonds (HBintra) increased by 11.6 % and 4.8 % after hydrogen peroxide bleaching and sodium dithionite bleaching, respectively. The energy of the hydrogen bonds was changed after bleaching treatment. The hydrogen bonding distances showed a small change after different bleaching treatment. The results of X-ray diffraction (XRD) demonstrated a decrease in the average width of crystallite size in the (002) lattice plane after different bleaching treatment, which was the same trend with the variability of cellulose crystallinity. Compared with the unbleached pulp, the WRV and strength properties of the bleached pulp increased after each bleaching process. Tear index of handsheets made from the hydrogen peroxide and sodium dithionite bleaching pulps were 46.0 % and 54.8 %, respectively. The sodium dithionite bleaching treatment had more significant effects on fiber swelling capability.
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CARREIRA, HÉLIO J. M., PEDRO E. G. LOUREIRO, M. GRAÇA V. S. CARVALHO, and DMITRY V. EVTUGUIN. "Reductive degradation of residual chromophores in kraft pulp with sodium dithionite." March 2012 11, no. 3 (April 1, 2012): 59–67. http://dx.doi.org/10.32964/tj11.3.59.

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The focus of this study is the chemistry of reductive bleaching of kraft pulps with sodium dithionite. A set of model compounds mimicking quinone structures, residual lignin structures with conjugated carbonyl/carboxyl groups and muconic acid, among others, was reduced with sodium dithionite and monitored by ultraviolet-visible (UV-vis) spectroscopy. Depending on the chromophore models, either reductive or sulfonation reactions are thought to be responsible for the degradation. No reductive degradation of hexeneuronic acid (HexA) residues was detected, but unsaturated structures of unknown origin were eliminated from the xylan. Additionally, the potential of the reductive stage with either sodium dithionite or sodium borohydride was tested using an industrial pine kraft pulp bleached by OOZEDD sequence. This pulp, with a 88.8% ISO brightness ceiling, exhibited a brightness increase to 90 ± 0.5% in the final reduction stage.
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Dissertations / Theses on the topic "Sodium dithionite"

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Chalmin, Louis-Andre Odile. "Propriétés réductrices du dithionite de sodium dans des conditions de transfert de phase." Lyon 1, 1985. http://www.theses.fr/1985LYO19061.

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Deux approches sont envisagees : la catalyse par transfert de phase et la fixation de l'anion dithionite sur polymere. L'etude comparative des proprietes extractantes de differents agents de transfert a montre la superiorite du cation methyl trioctylammonium. Reduction d'aldehydes et de cetones par le dithionite de na dans les conditions de transfert de phase. Reduction par l'anion dithionite fixe sur resines echangeuses d'ions
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Vegunta, Vijaya Lakshmi. "A study on the thermal stability of sodium dithionite using ATR-FTIR spectroscopy." Thesis, KTH, Fiber- och polymerteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-197370.

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Sodium dithionite (Na2S2O4) is a powerful reducing agent. It has therefore been suggested to be used as an additive in kraft pulping to improve the yield. However, sodium dithionite easily decomposes and it is thus important to determine the effect of different conditions. The aim of this thesis has been to investigate the thermal stability of sodium dithionite under anaerobic conditions using ATR-FTIR spectroscopy under different conditions, such as heating temperature, concentration of the solution, heating time and pH. The stability of sodium dithionite was found to decrease with increasing heating temperature, concentration of sodium dithionite, heating time and pH. Sodium dithionite was found to be relatively stable at moderate alkaline pH:s 11.5 and 12.5, while a rapid decrease in stability with time was noted at higher heating temperatures and concentrations of sodium dithionite. Based on this study on the thermal stability of sodium dithionite, the following conditions are suggested as the most promising, when adding sodium dithionite to the kraft cooking as an additive; pH 12.5, with 0.4 M concentration of the solution, at a heating temperature of 100 °C.
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Wang, Yan. "Pretreatment and Enzymatic Treatment of Spruce : A functional designed wood components separation for a future biorefinery." Doctoral thesis, KTH, Träkemi och massateknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-150395.

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The three main components of wood, namely, cellulose, hemicellulose, and lignin, can be used in various areas. However, since lignin covalently crosslinks with wood polysaccharides creating networks that is an obstacle for extraction, direct extraction of different wood components in high yield is not an easy matter. One potential approach to overcome such obstacles is to treat the wood with specific enzymes that degrade the networks by specific catalysis. However, the structure of wood is so compact that the penetration of the wood fibers by large enzyme molecules is hindered. Thus, the pretreatment of wood prior to the application of enzymes is necessary, for “opening” the structure. One pretreatment method that was performed in this thesis is based on kraft pulping, which is a well-established and industrialized technique. For untreated wood, the wood fibers cannot be attacked by the enzymes. A relatively mild pretreatment was sufficient for wood polysaccharides hydrolyzed by a culture filtrate. A methanol-alkali mixture extraction was subsequently applied to the samples that were pretreated with two types of hemicellulases, Gamanase and Pulpzyme HC, respectively. The extraction yield increased after enzymatic treatment, and the polymers that were extracted from monocomponent enzyme-treated wood had a higher degree of polymerization. Experiments with in vitro prepared lignin polysaccharide networks suggested that the increased extraction was due to the enzymatic untying. However, the relatively large loss of hemicellulose, particularly including (galacto)glucomannan (GGM), represents a problem with this technique. To improve the carbohydrate yield, sodium borohydride (NaBH4), polysulfide and anthraquinone were used, which increased the yields from 76.6% to 89.6%, 81.3% and 80.0%, respectively, after extended impregnation (EI). The additives also increased the extraction yield from approximately 9 to 12% w/w wood. Gamanase treatment prior to the extraction increased the extraction yield to 14% w/w wood. Sodium dithionite (Na2S2O4) is an alternative reducing agent for the preservation of hemicelluloses because it is less expensive than metal hydrides and only contains sodium and sulfur, which will not introduce new elements to the recovery system. Moreover, Na2S2O4has the potential to be generated from black liquor. Na2S2O4 has some preservation effect on hemicelluloses, and the presence of Na2S2O4 also contributed to delignification. The extraction yield increased to approximately 15% w/w wood. Furthermore, Na2S2O4 has been applied in the kraft pulping process of spruce. The yield and viscosity increased, while the Klason lignin content and kappa number decreased, which represents a beneficial characteristic for kraft pulp. The brightness and tensile strength of the resulting sheets also improved. However, the direct addition of Na2S2O4 to white liquor led to greater reject content. This problem was solved by pre-impregnation with Na2S2O4 and/or mild steam explosion (STEX) prior to the kraft pulping process. Following Na2S2O4 pre-impregnation and mild STEX, the obtained kraft pulp had substantially better properties compared with the properties exhibited after direct addition of Na2S2O4 to the white liquor. The wood structure opening efficiency of mild STEX alone was also tested. The accessibility of the wood structure to enzymes was obtained even at very modest STEX conditions, according to a reducing sugar analysis, and was not observed in untreated wood chips, which were used as a reference. The mechanical effect of STEX appears to be of great importance at lower temperatures, and both chemical and mechanical effects occur at higher STEX temperatures.

QC 20140903

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Pandey, Dhurba Raj. "Degradation of Select Chlorinated Hydrocarbons by (i) Sulfide-Treated Hydrous Ferric Oxide (HFO) and (ii) Hydroxyl Radicals Produced in the Dark by Oxygenation of Sodium Dithionite-Reduced HFO." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1535462165887662.

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Claude-Montigny, Bénédicte. "Influence de polyélectrolytes et micelles sur la cinétique de transfert d'électrons entre l'ion dithionite et des dialkyl viologénes : rôle des interactions électrostatiques et hydrophobes, et stabilisation des viologénes réduits." Nancy 1, 1993. http://www.theses.fr/1993NAN10008.

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Par la technique du stopped-flow nous avons mené une étude systématique de l'effet du microenvironnement, apporte par des polyélectrolytes, des cyclodextrines, des micelles et des microémulsions, sur la cinétique de transfert d'électron entre un donneur, le dithionite de sodium et différents accepteurs, une série de dialkyl viologénes d'hydrophobie variable. Ceci nous a permis d'avoir une meilleure compréhension des contributions respectives des interactions électrostatiques et hydrophobes, qui jouent un rôle primordial dans le phénomène de séparation de charges directement lié au problème de conversion et de stockage de l'énergie solaire. Les constantes de vitesse apparentes pour la réduction des viologénes ont été déterminées dans les différents milieux. L'effet de retard le plus important (environ 50 fois) a été obtenu avec un copolymère de l'acide maléique et du cetyl vinyl éther. Des modèles théoriques ont été développés pour rendre compte de l'effet des polyélectrolytes. Les différents milieux considérés peuvent avoir un effet de stabilisation sur les viologénes réduits à caractère fortement hydrophobe, en empêchant leur dimerisation. Les constantes de vitesse apparentes pour la dimerisation ont été déterminées à partir de modèles théoriques et l'effet de stabilisation confirme par RPE
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Schindler, Manon. "Deracémisation du chlorate de sodium avec et sans l’influence du dithionate de sodium." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR004.

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Dans le domaine pharmaceutique, la séparation des énantiomères est souvent effectuée par des méthodes de cristallisation. L’avantage de la déracémisation est la possibilité d’obtenir un rendement théorique de 100% grâce à la conversion du contre énantiomère en l’énantiomère désiré en solution. Le mécanisme de la déracémisation par cycles de température (TCID), a été étudié dans ce manuscrit. Les recherches se sont concentrées sur le développement d’un procédé de TCID pour NaClO3. Ce composé modèle pour la déracémisation est achiral à l’état solvate, ce qui permet de se focaliser sur les mécanismes de cristallisation impliqués dans le procédé de déracémisation. Après la caractérisation complète de l’état solide de Na2S2O6, ce composé a été utilisé comme une impureté nonchirale dans le procédé de TCID du NaClO3 et a permis de mettre en évidence le rôle important de la nucléation secondaire dans le procédé. Ainsi, le succès du TCID dépend d’un bon équilibre entre la croissance des cristaux et la nucléation secondaire. A des fins industrielles, les réacteurs du type Couette Taylor sont des appareils prometteurs pour le développement de procédés de déracémisation en continu. Les premiers tests de déracémisation réalisés dans ce type de réacteur ont montré que la brisure de symétrie et la déracémisation du NaClO3 ont été réalisés avec succès. Néanmoins, le ≪ recyclage de cristaux ≫, soit par attrition soit par la nucléation secondaire, doit être amélioré pour obtenir un procédé de déracémisation plus performant avant de considérer l’implémentation d’un procédé en continu
In the field of pharmaceutical chemistry, crystallization based methods are used to obtain pure enantiomers. The advantage of deracemization is the conversion of the unwanted enantiomer into the desired enantiomer by means of racemization in liquid phase, giving rise to a theoretical yield of 100%. The mechanism of Temperature Cycling Induced Deracemization (TCID) process, still matter of debate, has been investigated in this thesis. Research was focused on the development of the TCID process for sodium chlorate (NaClO3). This model compound is achiral at the solvated state which enables to focus investigation on crystallization mechanisms involved during deracemization. After the full solid state characterization of sodium dithionate (Na2S2O6), this compound has been used as a nonchiral impurity in the TCID process of NaClO3 and highlighted the key role of secondary nucleation in the process. Thus, the success of the TCID process depends on the right balance between growth and secondary nucleation. From an industrial perspective, the Couette Taylor reactor has been considered as a promising device for the development of continuous deracemization process. Attempts to deracemize NaClO3 in this kind of reactor showed that symmetry breaking and deracemization of NaClO3 were successful. Nonetheless, crystal recycling, via either attrition or secondary nucleation, has to be improved to enhance deracemization process before considering the execution of continuous process
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Lan, Zhipeng. "The structural role of sodium dithionate impurity in the habit modification of sodium chlorate single crystals." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/6311/.

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A detailed study into the crystal habit modification of the NaClO3 / Na2S2O6 (host / impurity) system is presented. Ordinary morphology of NaClO3 present faces of {001}, {110} and {111} types. The presence of impurity Na2S2O6 has led to rapid development of new faces of {111} type on the NaClO3 crystals grown from solution. Above 70ppm doping concentration, the morphology of NaClO3 crystal is dominated by {111} faces. Crystal twinning occurred under 800ppm doping concentration and above. X-ray topography was used to investigate the growth history and defect configuration of the pure and doped crystals. Lattice distortions at various lattice planes within the pure and doped crystals were determined using X-ray multiple-wave diffraction (XRMD). The local structure of S2O6 2- in NaClO3 crystal was determined using X-ray absorption fine structure (XAFS). Molecular modelling was applied to investigate the molecular similarity between the impurity and the host. Strong impurity incorporation in the {111} sectors was revealed by X-ray topography. The growth history of doped crystal was reconstructed and interpreted with respect to the inhibiting effect of S2O6 2-. Disturbance in lattice planes of doped crystals was investigated, which was attributed to the incorporation of S2O6 2- on { 111} faces. It also revealed different types of local strain on the { 111 } faces along two different directions. The three-dimensional orientation and the actual structure of S2O6 2- impurity on the {111} faces of NaClO3 crystal were obtained. A structural model for the impurity incorporation was established, showing good consistency with the experimental results. In addition, the segregation coefficient of the impurity was determined by elemental mapping, indicating strong impurity incorporation on the {111} faces rather than others. The incorporated S2O6 2- was concluded to be capable of disrupting the proper packing structure of the {111} faces, obstructing the generation and propagation of growth steps, and decreasing of driving force for crystal growth.
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Walter, Karin. "Influence of acid hydrogen peroxide treatment on refining energy and TMP properties." Licentiate thesis, Mid Sweden University, Department of Natural Sciences, Engineering and Mathematics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-9207.

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The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. The produced TMPs were thoroughly characterised in order to explain the effect of the chemical system on fibre development and to be able to propose a mechanism for the impact on refining energy reduction. The possibility to improve the optical properties by washing, chelating and sodium dithionite or hydrogen peroxide bleaching the treated pulps was evaluated.

 

The results obtained in a pilot plant trial show that it is possible to significantly reduce the comparative specific energy consumption by approximately 20% and 35% at a freeness value of 100 ml CSF or a tensile index of 45 Nm/g by using 1% and 2% hydrogen peroxide respectively. The energy reduction is obtained without any substantial change in the fractional composition of the pulp, though tear strength is slightly reduced, as are brightness and pulp yield. No major differences between the reference pulp and the chemically treated pulps were found with respect to fibre length, width or cross-sectional dimensions. However, the acid hydrogen peroxide-treated pulps tend to have more collapsed fibres, higher flexibility, a larger specific surface area and a lower coarseness value. The yield loss accompanying the treatment is mainly a consequence of degraded hemicelluloses. It was also found that the total charge of the chemically treated pulps is higher compared to the reference pulps, something that may have influenced the softening behaviour of the fibre wall.

 

A washing or chelating procedure can reduce the metal ion content of the chemically treated TMPs considerably. The amount of iron can be further reduced to a level similar to that of untreated pulps by performing a reducing agent-assisted chelating stage (QY) with dithionite. The discoloration cannot, however, be completely eliminated. The brightness decrease of the treated pulps is thus not only caused by higher iron content in the pulp, but is also dependent on the type of iron compound and/or other coloured compounds connected with the acid hydrogen peroxide treatment. Oxidative bleaching with hydrogen peroxide (P) is more effective than reductive bleaching with sodium dithionite in regaining the brightness lost during the energy reductive treatment. Using a QY P sequence, a hydrogen peroxide charge of 3.8% was needed to reach an ISO brightness of 75% for the chemically treated pulps. The corresponding hydrogen peroxide charge for the untreated TMP reference was 2.5%.

 

The radicals generated in the Fenton reaction will probably attack and weaken/soften the available outer fibre wall layers. This could facilitate fibre development and consequently lower the electrical energy demand for a certain degree of refinement.

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TSAI, TZAY-CHERNG, and 蔡再成. "The Sodium Dithionite Process From Sodium Formate." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/61783099177422538114.

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碩士
文化大學
應用化學系
85
Abstract The Sodium Dithionite manufactured process is made from Sodium Formate reacting with Sulfur Dioxide and Sodium Hydroxide. Based on the test datum, try to find the optimum condition ex. SO2 feed concentration, SO2/HCOONa Feed ratio, HCOOCH3 content in Methanol, reaction temperature, enable to increase the purity of Na2S2O4 product, meanwhile to develop the whole production process.
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Hu, Hong-Liang. "Electrochemical brightening of pulp with sodium dithionite generated in-situ." Thesis, 1994. http://hdl.handle.net/2429/4996.

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This study consisted of three parts, an investigation of potential reducing agents, an investigation of conventional dithionite brightening at 1% pulp consistency and an investigation of in-situ electrochemically generated dithiomte brightening. Preliminary brightening experiments by four reducing agents, hydrazine sulfate, hydroquinone, hydroxylamine sulfate and sodium hypophosphite were conducted. At 60 °C, with 1 hour brightening period, 4 to 16 wt% brightening agent charge and 0.5 wt% chelating agent charge on od pulp under nitrogen purge, these agents could only achieve a brightness gain of up to 4 % ISO. They were less effective than sodium dithionite in mechanical pulp brightening. Sodium dithionite brightening of softwood TMP at 60 °C and 1% pulp consistency was done with a single addition of dithionite, multiple addition of dithionite and addition of dithionite in multiple stages with interstage washing. With a single addition of the same dithionite charge, the brightness gain at 1 % pulp consistency was equal to that in conventional brightening at 3 to 4% pulp consistency. For a given total sodium dithionite charge on od pulp, addition of clithionite in multiple stages with interstage washing could achieve about 1 % ISO higher brightness gain than multiple addition of dithionite in a single run, while multiple addition of dithionite in a single run could achieve about 1 % ISO higher brightness gain than a single addition of dithionite. The time and amount of each charge did not seem to affect the brightness gain for multiple additions of dithiomte. In dithionite brightening with a large amount of (bi)sufflte (13 to 131 wt% sodium sulfite on od pulp), the brightness gain was about 3 % ISO lower than that with only dithionite, but about 4 % ISO higher than that with only sulfite. Sodium bisulfite and dithionite reaction products seemed to decrease dithionite brightening capability. The addition of 2-propanol or methanol could alleviate this negative effect of sodium bisuffite on dithionite brightening by about 1% Iso. The electrochemical synthesis of sodium dithionite (without pulp) was conducted in a 1 L mixed tank batch reactor evenly divided by a cation exchange membrane with cathode area of 5500 to 13000 mm². Runs were carried out at 40 °C and 60 °C. High time average dithionite concentration (5 to 10 g/l) and fairly good current efficiency (35 - 80 %) were obtained at high current ( ≥2.3 A) together with high sodium sulfite dose (≥25.3 g). Dithionite concentration became very low ( 0 to 1 g/l) at low sulfite dose (4.6 g). Cathode area, current and sodium sulfite dose were very significant variables in this process. Increases in these variables raised the time average dithionite concentration. Increases in cathode area as well as increases in sulfite dose raised the final current efficiency for dithionite generation. Decreases in current raised final current efficiency with the cathode of 5500 mm² area, but did not have significant effect with cathode of 13000 mm² area. In-situ electrochemically generated sodium dithionite brightening at ambient temperature was briefly investigated in Plexiglas reactor of the same dimensions as the reactor given above, but with a cathode of 1000 mm² area. These runs gave a maximum brightness gain of about 5 % ISO. In-situ electrochemically generated sodium dithionite brightening at elevated temperature was extensively investigated with the same reactor and cathodes used in the electrosynthesis of dithionite. When electrochemical dithionite brightening was carried out at 0.8 % consistency in the following ranges: pH (4.0 to 5.5), sodium sulfite dose (4.6 to 46.0 g), current (0.5 to 4.0 A) and temperature (40 to 60 °C), the highest range of brightness gain was 8 to 9 % ISO with time average dithionite concentration equivalent to a charge of 10 to 103 wt% on od pulp. This highest range of brightness gain was obtained at any pH with a combination of high sulfite dose (46.0 g), high temperature (60 °C) and high current (4 A). At pH 5.5, this highest range of brightness gain was also obtained with a combination of high sulfite dose (46.0 g), high temperature (60 °C) and low current (0.5 A). Temperature had the most significant effect on brightness gain in this process, increases in temperature raised brightness gain but lowered the final net current efficiency for dithionite generation. Increases in cathode area, addition of 2-propanol and chromium did not raise this highest range of brightness gain in the ranges of operating variable studied. In the subsequent optimization of brightness gain for in-situ electrochemically generated dithionite brightening at 2% consistency, the highest range of brightness gain obtained was 11 to 12 % ISO, which was only obtained at the highest range of temperature (74 to 83 °C), with time average dithionite concentration equivalent to a charge of 7 to 10 wt% on od pulp along with a very poor final current efficiency for dithionite (0 to 13 %). Yellowness decreased in electrochemical dithionite brightening in the same way as in conventional dithionite brightening. Comparing the brightness gain of the blank experiment (no current) to the highest brightness gain obtained from the electrochemical dithionite brightening at the same sodium suffite dose, temperature, pH and pulp consistency, the maximum further brightness gain contributed by the brightening species generated by current was only about 4 % ISO. For a brightness gain of 11.4 % ISO, the fraction of the brightness gain contributed by the brightening species generated by current was about 26 % of the total brightness gain.
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Books on the topic "Sodium dithionite"

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Makarov, Sergei V. Sodium Dithionite, Rongalite, and Thiourea Oxides: Chemistry and Application. World Scientific Publishing Co Pte Ltd, 2016.

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Book chapters on the topic "Sodium dithionite"

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Anes, I. A., A. B. Botelho Junior, D. C. R. Espinosa, and J. A. S. Tenório. "Effect of pH and Potential in Chemical Precipitation of Copper by Sodium Dithionite." In Energy Technology 2019, 165–74. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-06209-5_17.

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Botelho Junior, A. B., I. A. Anes, M. A. Carvalho, D. C. R. Espinosa, and J. A. S. Tenório. "Recovery of Copper from Nickel Laterite Leach Waste by Chemical Reduction Using Sodium Dithionite." In Energy Technology 2018, 429–34. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-72362-4_38.

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Botelho Junior, A. B., I. A. Anes, M. A. Carvalho, D. C. R. Espinosa, and J. A. S. Tenório. "Erratum to: Recovery of Copper from Nickel Laterite Leach Waste by Chemical Reduction Using Sodium Dithionite." In Energy Technology 2018, E1. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-72362-4_57.

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Masse, C. E. "From Dibromosuccinates with Sodium Dithionite." In Three Carbon-Heteroatom Bonds: Acid Halides; Carboxylic Acids and Acid Salts, 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-020-00889.

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Prakash, G. K. S., and J. Hu. "Reaction of Dibromochlorofluoromethane and Sodium Dithionite." In Three Carbon-Heteroatom Bonds: Amides and Derivatives; Peptides; Lactams, 1. Georg Thieme Verlag KG, 2005. http://dx.doi.org/10.1055/sos-sd-022-00795.

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Zhang, M., and P. R. Hanson. "Use of Sodium Dithionite Reducing Agents." In Three Carbon-Heteroatom Bonds: Acid Halides; Carboxylic Acids and Acid Salts, 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-020-00815.

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"Introduction." In Sodium Dithionite, Rongalite and Thiourea Oxides, 1–3. WORLD SCIENTIFIC (EUROPE), 2016. http://dx.doi.org/10.1142/9781786340962_0001.

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"Synthesis." In Sodium Dithionite, Rongalite and Thiourea Oxides, 5–19. WORLD SCIENTIFIC (EUROPE), 2016. http://dx.doi.org/10.1142/9781786340962_0002.

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"Structure." In Sodium Dithionite, Rongalite and Thiourea Oxides, 21–32. WORLD SCIENTIFIC (EUROPE), 2016. http://dx.doi.org/10.1142/9781786340962_0003.

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"General Properties and Analysis." In Sodium Dithionite, Rongalite and Thiourea Oxides, 33–38. WORLD SCIENTIFIC (EUROPE), 2016. http://dx.doi.org/10.1142/9781786340962_0004.

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Conference papers on the topic "Sodium dithionite"

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Wojciechowski, Krzysztof. "Relation between morphology, growth kinetics, and quality of sodium chlorate crystals grown from pure and sodium-dithionate-doped solutions." In Solid State Crystals: Materials Science and Applications, edited by Jozef Zmija. SPIE, 1995. http://dx.doi.org/10.1117/12.224940.

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Reports on the topic "Sodium dithionite"

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Telfeyan, Katherine Christina. The Use of Sodium Dithionite for the Remediation of Hexavalent Chromium in Mortendad Canyon. Office of Scientific and Technical Information (OSTI), February 2018. http://dx.doi.org/10.2172/1422944.

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