Sodium Dithionite Research Articles

Mao berry as a green reducing agent in natural indigo dyeing on cotton fabrics

In this work, mao berry extract was tested to determine whether it could be a green alternative reducing agent in the indigo dyeing on cotton fabrics. Glucose and fructose, which are the main reducing sugars in the extract, could reduce natural indigo pigment into its water soluble leuco form in the alkaline solution. Sodium hydroxide and calcium hydroxide were compared for their effectiveness in the alkaline reduction of indigo. The reduction potentials of the indigo dyebath using mao berry extract were evaluated with reference to the conventional reducing agent, sodium dithionite (Na2S2O4), and different reducing sugars. The results from colour strength and colour fastness to washing, light and rubbing of the dyed cotton fabrics using the extract were comparable with other reducing agents especially in NaOH. Mao berry extract gave satisfactory results as a green alternative to Na2S2O4 in the natural indigo dyeing process. Moreover, the UV protection ability of the dyed cotton fabrics was enhanced by the natural indigo dyes applied.

Effective reduction clearing parameters involving alternative reducing agent

Dyeing of polyester is done by using disperse dyes. Some of the disperse dyes remain unfixed during dyeing and create problems in shade and colorfastness properties. Reduction clearing (RC) is a process to remove these unfixed dyes and to enhance colorfastness properties. In the Pakistani textile industry, reduction clearing is being done by using sodium dithionite (Na2S2O4), which has the best results in reducing dyestuff. The problem with sodium dithionite is that it is sensitive to air and also creates a lot of environmental issues. Its sensitivity causes inconsistent results of reduction clearing. Different dyers used different processes and recipes of reduction clearing. Thiourea Dioxide (TUD) is a green reducing agent and can be used as a replacement for sodium dithionite. TUD (CH4N2S) is a stable product with a comparable result with sodium dithionite. Interlock knitted fabric is used in this project whose composition has recycled polyester. The fabric was first dyed using black dyestuff and then reduction clearing was done on a lab-scale with different factors (Shade depth, the concentration of TUD, RC temperature). Three colorfastness tests were conducted to evaluate the different levels of each factor i.e. colorfastness to washing, fastness to perspiration, and fastness to water according to standard numbers ISO 105-C06, ISO 105-E04, and ISO 105-E01, respectively. It was observed that shade depth does not affect the results while concentration and RC temperature have a significant effect on the results. Moreover, the effective concentration of TUD was also determined.

The Effect of Environmental and Chemical Approach on rGO Structure

Reduced graphene oxide (rGO) and graphene oxide (GO) are gaining popularity among many research areas. rGO synthesis is based on bottom-up production, which consists of two different stages: the oxidation of graphite and the reduction of GO. The properties of rGO structure are determined by GO used as raw material, reducing agents and the type of process. Different chemical agents are used to reduce GO to rGO and among these, hydrazine is known to be the strongest and effective, but the most toxic agent.In this study, the rGO structure synthesized using sulfur-containing sodium dithionite (Na2S2O4) was compared with the rGO structure synthesized by L-ascorbic acid (Vitamin C) agent in terms of layer number, elemental analysis and crystal structures, and It has been observed that Na2S2O4 may be a good is a good alternative. to reduce GO. GO was synthesized by Modified Improved Hummers method without using toxic sodium nitrate. The reduced products were examined by FTIR, XRD and SEM/EDS. Results showed that different reducing agents synthesized similar rGO-Na2S2O4 and rGO-LAA structures with 0.34 nm interlayer space also they included % 14.27 and %12.24 of oxygen respectively.

Factors Affecting Detoxification of Softwood Enzymatic Hydrolysates Using Sodium Dithionite

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.

Cotton dyeing with indigo using alkaline pectinase and Fe(II) salt

An ecofriendly reducing agent, viz. alkaline pectinase alongwith iron (II) salt, has been used in place of sodium hydrosulphite for dyeing of cotton with indigo. Dyed samples are then characterized by ATR-FTIR, SEM and XRD. It is observed that the alkaline pectinase alongwith iron (II) salt reducing system is also capable of producing almost identical level of reduction potential in dye baths, reduction bath stability, dye strength and colour fastness properties of dyed cotton to those obtained with sodium hydrosulphite.

Menaquinone Biosynthesis: New Strategies to Trap Radical Intermediates in the MqnE-Catalyzed Reaction.

Aminofutalosine synthase (MqnE) is a radical SAM enzyme that catalyzes the conversion of 3-((1-carboxyvinyl)oxy)benzoic acid to aminofutalosine during the futalosine-dependent menaquinone biosynthesis. In this Communication, we report the trapping of a radical intermediate in the MqnE-catalyzed reaction using sodium dithionite, molecular oxygen, or 5,5-dimethyl-1-pyrroline-N-oxide. These radical trapping strategies are potentially of general utility in the study of other radical SAM enzymes.

A closed-loop sustainable scheme for silver recovery from water by reusable thiol-grafted graphene oxide

Two-dimensional graphene oxide was modified with mercaptoethylamine and then treated with sodium dithionite to produce a 3D thiol-grafted graphene oxide (TGO) composite, which was investigated for the highly selective recovery of silver ions from water. Scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the material before and after Ag+ adsorption. Batch adsorption experiments were carried out as a function of the initial Ag+ concentration, agitation time, temperature, and pH. The maximum adsorptive capacity of Ag+ by TGO, obtained from the Langmuir model, which fit the isotherm data well, reached 134.1 mg/g at 25 °C and a pH of 5.0. In addition, the adsorption was an endothermic process, and the adsorption kinetics followed the pseudo-second-order model. TGO was highly selective for Ag+; the selectivity factor of Ag+ reached 445 compared to Cu2+ ions and exceeded 1900 compared to Zn2+, Mg2+, Ca2+, Na+, and K+ ions. The adsorption of Ag+ on TGO induced the release of H+, and increased adsorption with increasing pH was observed. The adsorbed Ag+ can be proportionally desorbed using 1% HNO3. The reusability of TGO was confirmed by five cycles of adsorption-desorption-regeneration. The adsorption column studies indicated that TGO was stable in water and can be used as a filtering material for Ag+ recovery. The binding mechanism of Ag+ by TGO was proposed as the coordination of Ag+ with the sulfur atom of the mercapto groups attached to TGO followed by the reduction of Ag+ to Ag0.

Difluoroalkylation/1,2-aryl migration of allylic alcohols under transition metal-free conditions

A facile difluoroalkylation and 1,2-aryl migration reaction commencing from allylic alcohols and simple BrCF2COOEt was developed. This metal-free method offers chemists green and efficient access to important difluoro 1,5-dicarbonyl compounds in moderate to good yields with good functional group tolerance. Sodium hydrosulfite was used as a low-toxic, cheap, environmentally friendly, and efficient radical initiator. The feasibility of performing the transformation on a large scale potentially allows the further application of the present method in other fields.

Ethyl 1-Butyl-2-(2-hydroxy-4-methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate

Ethyl 4-(butylamino)-3-nitrobenzoate upon “one-pot” nitro-reductive cyclization using sodium dithionite and substituted aldehyde in dimethyl sulphoxide affords ethyl 1-butyl-2-(2-hydroxy-4-methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate in an 87% yield. The structural characterization was determined by Fourier-transfer infrared spectroscopy (FT-IR), Proton nuclear magnetic resonance (1H-NMR), Carbon-13 nuclear magnetic resonance (13C-NMR), mass spectrometry, Ultraviolet-visible(UV-Vis), photoluminescence (PL), thin-film solid emission spectra, cyclic voltammetry (CV) and thermogravimetric (TGA) analysis. Molecular electrostatic potential (MEP) was studied to determine the reactive sites of the molecule.

Dihydroactinidiolide regulates Nrf2/HO-1 expression and inhibits caspase-3/Bax pathway to protect SH-SY5Y human neuroblastoma cells from oxidative stress induced neuronal apoptosis

Alzheimer’s disease (AD) etiology has been studied for a long time and it is found to be multifaceted involving the accumulation of amyloid β and tau protein. Oxidative stress is an early event in AD associated neurodegeneration provoking neuronal death through mitochondrial dysfunction and activation of caspase-3. Therefore we tested the efficacy of dihydroactinidiolide (DHAc), a monoterpene lactone against the oxidative load involved in AD like pathological conditions induced by sodium dithionite, glutamate, amyloid β and colchicine in SH-SY5Y cells. Some of the indicators of neurotoxicity like acetylcholinesterase activity, intracellular reactive oxygen species (ROS), nitrite content, lipid peroxidation, protein carbonylation, nuclear and membrane damage were found to be significantly high in the toxicant treated cells when compared to the control cells while DHAc pretreatment significantly restored the toxicant induced neuronal damage signatures. Caspase-3 activity was found to be increased in the toxicant treated cells while DHAc significantly reduced it. Western blotting and RT-PCR revealed that DHAc significantly increased anti-apoptotic Bcl-2 expression and mRNA levels of Nrf2 and HO-1. Therefore DHAc was found to protect SH-SY5Y cells from neurotoxicant induced oxidative stress and apoptosis by regulating cellular antioxidant defenses and apoptosis related genes.

Spectral deconvolution of redox species in the crotonyl-CoA-dependent NADH:ferredoxin oxidoreductase from Megasphaera elsdenii. A flavin-dependent bifurcating enzyme

We have undertaken a spectral deconvolution of the three FADs of EtfAB/bcd to the spectral changes seen in the course of reduction, including the spectrally distinct anionic and neutral semiquinone states of electron-transferring and bcd flavins. We also demonstrate that, unlike similar systems, no charge-transfer complex is observed on titration of the reduced M. elsdenii EtfAB with NAD+. Finally, and significantly, we find that removal of the et FAD from EtfAB results in an uncrossing of the half-potentials of the bifurcating FAD that remains in the protein, as reflected in the accumulation of substantial FAD•- in the course of reductive titrations of the depleted EtfAB with sodium dithionite.

Copper-Free Click Enabled Triazabutadiene for Bioorthogonal Protein Functionalization.

Aryl diazonium ions have long been used in bioconjugation due to their reactivity toward electron-rich aryl residues, such as tyrosine. However, their utility in biological systems has been restricted due to the requirement of harsh conditions for their generation in situ, as well as limited hydrolytic stability. Previous work describing a scaffold known as triazabutadiene (TBD) has shown the ability to protect aryl diazonium ions allowing for increased synthetic utility, as well as triggered release under biologically relevant conditions. Herein, we describe the synthesis and application of a novel TBD, capable of installation of a cyclooctyne on protein surfaces for later use of copper-free click reactions involving functional azides. The probe shows efficient protein labeling across a wide pH range that can be accomplished in a convenient and timely manner. Orthogonality of the cyclooctyne modification was showcased by labeling a model protein in the presence of hen egg proteins, using an azide-containing fluorophore. We further confirmed that the azobenzene modification can be cleaved using sodium dithionite treatment.

Novel Methods Using an Arthrobacter sp. to Create Anaerobic Conditions for Biobutanol Production from Sweet Sorghum Juice by Clostridium beijerinckii

Biobutanol can be produced by Clostridia via an acetone–butanol–ethanol (ABE) fermentation under strictly anaerobic conditions. Oxygen-free nitrogen (OFN) gas is typically used to create anaerobic conditions for ABE fermentations. However, this method is not appropriate for large-scale fermentations as it is quite costly. The aim of this work was to study the feasibility of butanol production from sweet sorghum juice (SSJ) by Clostridium beijerinckii TISTR 1461 using various methods to create anaerobic conditions, i.e., growth of a strictly aerobic bacterium, an Arthrobacter sp., under different conditions and a chemical method using sodium dithionite (SDTN) to consume residual oxygen. SSJ containing 60 g/L of total sugar supplemented with 1.27 g/L of (NH4)2SO4 was used as a substrate for butanol production. The results showed that 0.25 mM SDTN could create anaerobic conditions, but in this case, C.beijerinckii TISTR 1461 could produce butanol at a concentration (PB) of only 8.51 g/L with a butanol productivity (QB) of 0.10 g/L·h. Arthrobacter sp. BCC 72131 could also be used to create anaerobic conditions. Mixed cultures of C.beijerinckii TISTR 1461 and Arthrobacter sp. BCC 72131 created anaerobic conditions by inoculating the C.beijerinckii 4 h after Arthrobacter. This gave a PB of 10.39 g/L with a QB of 0.20 g/L·h. Comparing butanol production with the control treatment (using OFN gas to create anaerobic conditions, yielding a PB of 9.88 g/L and QB of 0.21 g/L·h) indicated that using Arthrobacter sp. BCC 72131 was an appropriate procedure for creating anaerobic conditions for high levels of butanol production by C. beijerinckii TISTR 1461 from a SSJ medium.

Urine Sodium Dithionite Test for Determining Prognosis and Outcome of Paraquat Poisoning

Objective: To determine the association between urine sodium dithionite test result, testing time from paraquat (PQ) exposure, and mortality or systemic effect in patients with PQ poisoning. Materials and Methods: A retrospective study at the poison center identified cases with PQ exposure that receive urine sodium dithionite test results between 2015 and 2016. Urine sodium dithionite test results were reported in four groups, 1) no change in urine color, 2) green or light blue color, 3) dark blue color, and 4) purple or black color. Results: One hundred ten PQ exposures with urine sodium dithionite test results are included in the present analysis. Multivariate analysis showed that age, initial urine sodium dithionite test color, and testing time were independently associated with mortality. There were 26 deaths (23.6%). The mortality rate was different between groups classified by urine sodium dithionite test results and testing time from PQ exposure (p<0.01). In groups with the dithionite test performed within 12 hours of exposure, the mortality rates were 0 in the green or light blue group, 33.3% in the dark blue group, and 63.2% in the purple or black group. In groups with the dithionite test performed more than 12 hours after exposure, the mortality rates were 27.3% in the green or light blue group, 60.0% in the dark blue group, and 100% in the purple or black group. There were forty-eight patients with no change in urine color, all survived. In patients who survived, there were different systemic effect rates between groups classified by urine sodium dithionite test results and testing time. Conclusion: The initial urine sodium dithionite test result and testing time may be used as a tool to guide therapy and predict mortality and systemic involvement in patients with PQ poisoning. Keywords: Urine sodium dithionite test, Prognostic factor, Mortality rate, Systemic effect

Using sodium dithionite as a reducing agent in the synthesis of propacetamol hydrochroride from phenol

Propacetamol, a prodrug form of paracetamol, is used in injections for fast and effective pain relief. Propacetamol is water soluble and is used in postoperative care as well as intravenous administration in case the patients cannot take oral or rectal paracetamol. Studies on propacetamol synthesis at laboratory scale as well as industrial scale with safe, simple and economic procedures are crucial. In this study, we synthesized propacetamol from phenol as the starting material. In the first step, phenol was converted to p-nitrosophenol through a nitrosation process. This nitrosation reaction yielded the optimal result as the reaction selectively occured, the product was not plasticized. Next, p-nitrosophenol was reduced to p-aminophenol in the presence of sodium dithionite as the reducing agent. The reaction produced p-aminophenol at a yield of 89,6% with high selectivity and less impurity. After that, paracetamol was obtained through acetylation of p-aminophenol. Ochloroacetylation of paracetamol was performed by using the amount of diethylamine reduced by 2,5 times compared to previous studies to form 4-acetamidophenyl-2-chloroacetate in 85,5% yield. This intermediate was then alkylated to form propacetamol base, followed by treatment with HCl solution in acetone at low temperature to obtain propacetamol hydrochloride in 32,5% yield. The study has shown that propacetamol hydrochloride was successfully achieved with high efficiency and safety from phenol as the starting compound.

Clay minerals identification in rock varnish by XRD: A one-step reduction approach

Rock varnishes are known to be fine, dark, glossy submicron films found in deserts bare rock surfaces. The oxides and hydroxides of manganese and iron bind together the clay minerals present in the varnish layer. The processes of oxide-hydroxide accumulation at varnish sites are due to iron and manganese oxidizing bacteria which may require clay minerals for additional nutrition. Quantification and identification of clay minerals in this biofilm is needed to understand its formation. Past attempts to analyze the mineralogical composition of rock varnish have led to inconclusive results as varnish is a submicron thin layer composed of a complex mineral matrix. The elimination of non-crystalline cementing groups comprising of free iron oxides is a key step in the identification of many types of clay minerals, particularly in soil/sediment mineral studies.•The Fe-Mn oxide-hydroxide coatings, acting as cementing materials, can be easily removed using a one-step reduction method employing Na2S2O4 at 70 °C, leading to separation of clay minerals.•We have taken the lead from earlier reported Jackson (1958) method, wherein a combination of reagents was used such as sodium acetate, sodium citrate, hydrogen peroxide, sodium bicarbonate, and sodium dithionite for removing carbonate, organic carbon and Fe-Mn oxy-hydroxide coatings respectively from sediment grains to segregate individual grains from each other.•Our modification helps in the unveiling of clay minerals from a solid substrate and reports the X-ray diffraction peaks, which are elsewise hard to detect and therefore earlier studies are inconclusive.

Self-Supported Reduced Graphene Oxide Membrane and Its Cu2+ Adsorption Capability.

Graphene stratiform membrane materials have been recently applied to heavy metal removal in aqueous systems via adsorption due to their high mechanical strength, chemical stability, and other properties. We applied reduced graphene oxide (rGO) alone as an adsorbent to remove heavy metal ions from wastewater. Self-supported rGO membrane was prepared using a green reduction method with sodium hydrosulfite. We used the Raman spectra to observe the structure of the rGO membrane. The morphology of the self-supported membrane was measured by a scanning electron microscope. The Cu2+ adsorption performance was measured in terms of pH, reaction time, metal ion concentration, and temperature. The maximum Cu2+ adsorption capacity of the rGO membrane was found to be 149.25 mg/g. The adsorption process followed a pseudo-second-order kinetic model, and adsorption isotherms were simulated by the Freundlich model.

Chemoenzymatic semisynthesis of caffeic acid β-phenethyl ester, an antioxidative component in propolis, from raw coffee bean extract.

Caffeic acid β-phenethyl ester (CAPE), an antioxidative bioactive catechol isolated from propolis, was semisynthesized from chlorogenic acid and related compounds in an extract of raw (unroasted) Robusta coffee (Coffea canephora) beans in 5 steps and a total yield of 31%. Oxidative degradation of the intermediates and target molecule was prevented by alkaline hydrolysis of the chlorogenic acids in the presence of sodium dithionite (Na2S2O4) and deprotection of the catecholic diacetate precursor by Candida antarctica lipase B-mediated transesterification as the final step.

Experiments to determine the suitability of sodium dithionite treatment for a Cr(VI) groundwater plume in a deep aquifer of the United States Southwest

Legacy industrial waste has left groundwater plumes of hexavalent Cr (Cr(VI)) that requires treatment, predominantly by reduction to Cr(III) and subsequent precipitation. One promising technology is the injection of a strong reducing agent, sodium dithionite, to create an in-situ redox barrier, but implementation requires a comprehensive understanding of the reactions occurring with dithionite injection. Batch and column experiments were conducted with aquifer sediments to determine both the significant reactions and efficacy of sodium dithionite treatment for a groundwater plume of hexavalent chromium. The batch experiments demonstrate consumption of dithionite over the experiment (disappearance by 43 d) concurrent with leaching of about 1 mM Fe from the sediments. Reactions deduced from batch experiments were incorporated into a 1-D numerical model to simulate reactions occurring during the column injection. The treatment was able to successfully reduce approximately 30 pore volumes of groundwater containing 800 µg kg−1 Cr(VI). The experiments also demonstrate that although mineral forms of Fe are important phases in the reduction of Cr(VI), Fe alone cannot account for the entire reduction capacity imparted to the sediments. Rather, the correlation between Cr and reduced S retained in the columns, combined with Scanning Electron Microscopy (SEM) of treated sediments, suggest that formation of reduced S phases contributes to the prolonged reduction capacity.

SYNTHESIS OF DIBENZO[cd, g]INDOLE

In this paper, a synthesis method is proposed and discussed for a compound not previously described – dibenzo [cd, g] indole. For the successful synthesis of the target compound we used the classical method based on well-known procedure of indoles obtaining according to Fisher method with some changes. Commercially available derivatives of anthracene were used as the starting compound since they already contain a ready-made system of three condensed aromatic rings and they reaction activity is rather high. The corresponding diazonium salt was obtained from 9-amino anthracene by reaction with ethyl nitrite. Attempts to obtain the diazonium salt by reaction the amine with inorganic nitrites in an acidic aqueous medium did not lead to a product with an acceptable yield. 9-Antryl hydrazine was prepared by reducing the diazonium salt under mild conditions. Reduction was carried out using sulfur dioxide in aqueous sodium hydrosulfite. Formaldehyde of 9-anthrylhydrazone was obtained from anthrylhydrazine after condensation with paraformaldehyde. The target product was obtained by intramolecular cyclization of hydrazone under the action of BF3 * Et2O under the condition of high dilution and low temperature. The physicochemical characteristics of all the obtained compounds are determined. Melting point was determined on a Stuart SMP-30 instrument. IR spectra were recorded on a Nicolet 380 FT-IR spectrometer in tablets with potassium bromide. NMR spectra were recorded on a Bruker DRX-400 spectrometer (400 MHz), Me4Si was used as a 1H standard, in CDCl3 as a solvent. Elemental analysis was performed on a EuroEA 3000 analyzer. Based on the data from the above analysis methods, it was concluded that the proposed structures correspond to the real ones. In addition, we can conclude that synthesized products are individual substances.