Sodium Anthraquinone-2-sulfonate Research Articles

Quinone Quest: Unraveling electrochemical performance in quinone-anchored 3D graphene architectures for high-energy supercapacitors

In the pursuit of advancing energy storage technologies, the exploration of novel electrode materials for supercapacitors, specifically organic materials, has garnered significant attention. This work delves into the electrochemical performance of quinone-anchored three-dimensional (3D) graphene (3DG) architectures as potential electrode materials for high-energy supercapacitors, focusing on elucidating the influence of different quinone types including 1,4-naphthoquinone (NQ), anthraquinone (AQ), duraquinone (DQ), p-benzoquinone (BQ), 2,5-dimethyl-1,4-benzoquinone (DMBQ), and sodium anthraquinone-2-sulfonate (SAQS). To that end, various quinone-anchored three-dimensional graphene (Q_3DG) architectures were synthesized via a chemical reduction-induced self-assembly technique in the presence of l-ascorbic acid, a green reducing agent. The physicochemical characterizations confirmed the successful incorporation of quinones to the carbon structure, without the presence of any impurities. Different interaction mechanisms between graphene oxide (GO) and quinone molecules during the synthesis led to different surface morphologies, which affected their electrochemical behavior. The 3-electrode electrochemical characterizations in 1.0 M Na2SO4 electrolyte revealed that all Q_3DG structures exhibited superior electrochemical performance compared to GO, as well as to a Bare_3DG sample synthesized without quinone molecules. NQ anchored 3DG (NQ_3DG) network yielded the highest specific capacitance value of 386.3 F.g−1 at 10 mV.s−1, which was almost 50 times larger than that of Bare_3DG. The findings not only shed light on the fundamental mechanisms governing charge storage and transfer within these unique architectures but also provide valuable insights for the rational and green design of next-generation organic electrode-based supercapacitors with enhanced energy storage capabilities.

Continuous Flow Approach for Benzylic Photo-oxidations Using Compressed Air.

A continuous flow approach for the aerobic photo-oxidation of benzylic substrates to ketone and aldehyde products is presented. The resulting process exploits UV-A LEDs (375 nm) in combination with a Corning AFR reactor that ensures effective gas-liquid mixing and leads to short residence times of 1 min. A variety of benzylic substrates are converted to their corresponding carbonyl products, and scalability is demonstrated to produce multigram quantities of products within a few hours. Overall, this continuous flow approach offers several improvements over alternative oxidation methods due to the combined use of air as an oxidant and SAS (sodium anthraquinone-2 sulfonate) as a water-soluble photocatalyst. The use of greener and safer conditions together with process intensification principles renders this flow approach attractive for further industrial applications.

Photocatalytic Oxidative Cleavage of Alkenes Followed by Carbonyl Stereoselective Bioreduction for the Synthesis of Enantioenriched Secondary Alcohols

AbstractOxidative alkene cleavage of a series of (hetero)aryl alkyl styrenes in aqueous medium has been developed using either 9‐mesityl‐10‐methylacridinium perchlorate ([AcrMes]ClO4) and sodium anthraquinone‐2‐sulfonate (SAS) as photosensitizers under blue LED irradiation. Reaction conditions were studied to find a suitable media for the development of a linear cascade after subsequent stereoselective reduction of the corresponding ketone intermediate. The use of cesium carbonate provided an adequate pH to the reaction medium for the alcohol dehydrogenase action. [AcrMes]ClO4 was found to be the best photocatalyst, allowing the development of concurrent or sequential cascades depending on the ability of the photosensitizer to oxidize back the chiral alcohol to the ketone. Overall, the photobiocatalytic approach has allowed the synthesis of a wide number of alcohol compounds, the formation of (S)‐ or (R)‐enantiomers being attained with excellent stereoselectivity and moderate to good yields.

Development of a spectrophotometric analytical approach for the measurement of cefdinir in various pharmaceuticals.

An accurate and sensitive determination procedure has been established for the quantification of cefdinir in pure and pharmacological formulas. The approach was dependent on derivatizing cefdinir with sodium anthraquinone-2-sulfonate (SAS) in an alkaline medium to produce a magenta-colored derivative with a maximum absorbance at 517 nm against the reagent blank. Different factors affecting the interaction of cefdinir with SAS were studied carefully and optimized, such as the buffer value, medium acidity, the duration of hydrolysis, and the reagent percentage. Under optimized conditions, a linear calibration curve with a correlation coefficient of R2 = 0.9995 was obtained over the concentration range of cefdinir 0.5-100 μg/mL. The values of the parameters that represented the sensitivity of the method were satisfactory, i.e., the limit of detection, the limit of quantification, as well as Sandell's sensitivity (л) were 0.1 μg/mL, 0.5 μg/mL, and 0.064 μg/cm2/0.001 Au, respectively. The relative standard deviation was below 1.35%, while the percentage recovery was 99.930%-102.257%. The mole ratio of the colored complex was estimated by following Job's method of continuous variation, which indicated that the cefdinir-SAS ratio was 1:1. The suggested approach was proven to be adequately accurate, precise, and without interfering with common excipients and additives. Thus, it could be implemented successfully for the standard determination of cefdinir in its pure and pharmaceutical forms.

Photocatalytic Oxidative Bromination of Electron‐Rich Arenes and Heteroarenes by Anthraquinone

AbstractThe estimated excited oxidation potential of sodium anthraquinone‐2‐sulfonate (SAS) increases from 1.8 V to about 2.3 V vs SCE by protonation with Brønsted acids. This increased photooxidation power of protonated anthraquinone was used for the regio‐selective oxidative bromination of electron rich (hetero)arenes and drugs in good yield. The mild reaction conditions are compatible with many functional groups, such as double and triple bonds, ketones, amides and amines, hydroxyl groups, carboxylic acids and carbamates. Mechanistic investigations indicate the photooxidation of the arene followed by nucleophilic bromide addition as the likely pathway.magnified image

Biodegradation of Xenobiotics in a fixed bed reactor

AbstractThe specific example of an at‐source biological wastewater treatment has been elaborated and developed. A two‐phase fixed‐bed bioreactor system was tested for its efficiency using phenol as a test substance and then, the degradation of sodium anthraquinone‐2‐sulfonate (SAS) was studied and performed.The continuous aerobic degradation of phenol or SAS as the sole source of carbon was investigated. For SAS degradation with an immobilized mixed bacterial culture, industrial activated sludge was used as inoculum, while for phenol a domestic activated sludge from a municipal wastewater treatment plant and activated Actizym‐sludge prepared with Actizym® powder were applied. In our laboratory fixed bed reactor system the adapted mixed culture was able to degrade up to 0.17 g L−1 h−1 of SAS and 0.28 g L−1 h−1 of phenol at dilution rates of 0.149 h−1 and 0.059 h−1, respectively. The removal efficiency of our two‐phase continuous bioreactor system was about 99% of primary and 90% of ultimate SAS degradation.In the adapted bacterial culture degrading SAS, pure bacterial strains were isolated and identified; three were gram negative and six were gram positive.