Towards a sustainable electrochemical activation for recycling CO2: synthesis of bis-O-alkylcarbamates from aliphatic and benzyl diamines

5-Hydroxymethylfurfural (HMF) is a very promising component for bio-based plastics. Efficient synthesis of HMF from biomass is still challenging because of fast degradation of HMF to by-products under formation conditions. Therefore, different studies, conducted mainly in monophasic and biphasic batch systems with and without water addition have been published and are still under investigation. However, to produce HMF at a large scale, a continuous process is preferable. Until now, only a few studies have been published in this context. In this work, it is shown that fluorous alcohol hexafluoroisopropanol (HFIP) can act as superior reaction solvent for HMF synthesis from fructose in a fixed bed reactor. Very high yields of 76% HMF can be achieved in this system under optimized conditions, whilst the catalyst is very stable over several days. Such high yields are only described elsewhere with high boiling reaction solvents like dimethylsulfoxide (DMSO), whereas HFIP with a boiling point of 58 °C is very easy to separate from HMF.

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Rapid Synthesis of Silver Nanoparticles fromFusarium oxysporumby Optimizing Physicocultural Conditions

The Scientific World JOURNAL ◽

10.1155/2013/796018 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 76

Author(s):

Sonal S. Birla ◽

Swapnil C. Gaikwad ◽

Aniket K. Gade ◽

Mahendra K. Rai

Keyword(s):

Silver Nanoparticles ◽

Large Scale ◽

Cost Effective ◽

Physical Parameters ◽

Malt Extract ◽

Rapid Synthesis ◽

Optimum Synthesis ◽

Optimized Conditions ◽

Sun Light ◽

Important Branch

Synthesis of silver nanoparticles (SNPs) by fungi is emerging as an important branch of nanotechnology due to its ecofriendly, safe, and cost-effective nature. In order to increase the yield of biosynthesized SNPs of desired shape and size, it is necessary to control the cultural and physical parameters during the synthesis. We report optimum synthesis of SNPs on malt extract glucose yeast extract peptone (MGYP) medium at pH 9–11, 40–60°C, and 190.7 Lux and in sun light. The salt concentrations, volume of filtrate and biomass quantity were found to be directly proportional to the yield. The optimized conditions for the stable and rapid synthesis will help in large scale synthesis of monodispersed SNPs. The main aim of the present study was to optimize different media, temperature, pH, light intensity, salt concentration, volume of filtrate, and biomass quantity for the synthesis of SNPs byFusarium oxysporum.

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Flow Battery Electroanalysis 2: Influence of Surface Pretreatment on Fe(III/II) Redox Chemistry at Carbon Electrodes

10.26434/chemrxiv.7125107.v1 ◽

2018 ◽

Author(s):

Tejal Sawant ◽

James McKone

Keyword(s):

Electron Transfer ◽

Photoelectron Spectroscopy ◽

Large Scale ◽

Redox Chemistry ◽

Rotating Disk Electrode ◽

Electrochemical Activation ◽

Carbon Electrodes ◽

Electron Transfer Kinetics ◽

Treatment Protocols ◽

Flow Batteries

Redox flow batteries are attractive for large-scale electrochemical energy storage, but sluggish electron transfer kinetics often limit their overall energy conversion efficiencies. In an effort to improve our understanding of these kinetic limitations in transition metal based flow batteries, we used rotating-disk electrode voltammetry to characterize the electron-transfer rates of the Fe3+/2+ redox couple at glassy carbon electrodes whose surfaces were modified using several pre-treatment protocols. We found that surface activation by electrochemical cycling in H2SO4(aq) electrolyte resulted in the fastest electron-transfer kinetics: j0 = 0:90 mA/cm2 in an electrolyte containing 10 mM total Fe. By contrast, electrodes that were chemically treated to either remove or promote surface oxidation yielded rates that were at least an order of magnitude slower: j0 = 0:07 and 0:08 mA/cm2, respectively. By correlating these findings with X-ray photoelectron spectroscopy data, we conclude that Fe3+/2+ redox chemistry is catalyzed by carbonyl groups whose surface concentrations are increased by electrochemical activation.

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Direct synthesis of dimethyl carbonate and propylene glycol using potassium bicarbonate as catalyst in supercritical CO2

Polish Journal of Chemical Technology ◽

10.1515/pjct-2015-0010 ◽

2015 ◽

Vol 17 (1) ◽

pp. 62-65 ◽

Cited By ~ 3

Author(s):

Yicun Wen ◽

Rui Zhang ◽

Yu Cang ◽

Jianchao Zhang ◽

Lixiao Liu ◽

...

Keyword(s):

Propylene Glycol ◽

Propylene Oxide ◽

Large Scale ◽

Dimethyl Carbonate ◽

Direct Synthesis ◽

Potassium Bicarbonate ◽

One Pot ◽

Optimized Conditions ◽

First Time ◽

By Products

Abstract The improved one-pot synthesis of dimethyl carbonate and propylene glycol from propylene oxide, supercritical carbon dioxide, and methanol with potassium bicarbonate as the catalyst has been reported in this paper. As far as we know, it is the first time to use potassium bicarbonate only as the catalyst in the production process which is simple and cheap. Satisfactory conversion rate of propylene oxide and yield of the products could be achieved at the optimized conditions with quite a small amount of by-products. Our new method offers an attractive choice for the production of dimethyl carbonate in large-scale industry efficiently and environmental friendly.

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Protamylasse, a Residual Compound of Industrial Starch Production, Provides a Suitable Medium for Large-Scale Cyanophycin Production

Applied and Environmental Microbiology ◽

10.1128/aem.71.12.7759-7767.2005 ◽

2005 ◽

Vol 71 (12) ◽

pp. 7759-7767 ◽

Cited By ~ 40

Author(s):

Yasser Elbahloul ◽

Kay Frey ◽

Johan Sanders ◽

Alexander Steinbüchel

Keyword(s):

Recombinant Strain ◽

Large Scale ◽

Luria Bertani ◽

Acid Extraction ◽

Bacterial Strains ◽

Biotechnological Production ◽

Mineral Salts ◽

Stirred Tank Reactors ◽

Initial Ph ◽

Optimized Conditions

ABSTRACT Protamylasse is a residual compound occurring during the industrial production of starch from potatoes. It contains a variety of nutrients and all necessary minerals and could be used as a carbon, nitrogen, and energy source for the growth of bacteria and also for cyanophycin (CGP) biosynthesis. Media containing protamylasse as the sole compound diluted only in water were therefore examined for their suitability in CGP production. Among various bacterial strains investigated in this study, a recombinant strain of Escherichia coli DH1 harboring plasmid pMa/c5-914::cphA 6803, which carries the cyanophycin synthetase structural gene (cphA) from Synechocystis sp. strain PCC6803, was found to be most suitable. Various cultivation conditions for high CGP contents were first optimized in shake flask cultures. The optimized conditions were then successfully applied to 30- and 500-liter fermentation scales in stirred tank reactors. A maximum CGP content of 28% (wt/wt) CGP per cell dry matter was obtained in 6% (vol/vol) protamylasse medium at an initial pH of 7.0 within a cultivation period of only 24 h. The CGP contents obtained with this recombinant strain employing protamylasse medium were higher than those obtained with the same strain cultivated in mineral salts medium or in expensive commercial complex media such as Luria-Bertani or Terrific broth. It was shown that most amino acids present in the protamylasse medium were almost completely utilized by the cells during cultivation. Exceptions were alanine, tryptophan, tyrosine, and most interestingly, arginine. Furthermore, CGP was easily isolated from protamylasse-grown cells by applying the acid extraction method. The CGP exhibited a molecular mass of about 26 to 30 kDa and was composed of 50% (mol/mol) aspartate, 46% (mol/mol) arginine, and 4% (mol/mol) lysine. The use of cheap residual protamylasse could contribute in establishing an economically and also ecologically feasible process for the biotechnological production of CGP.

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Experimental Study on the Through-Mask Electrochemical Micromachining (EMM) Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.692 ◽

2011 ◽

Vol 189-193 ◽

pp. 692-696 ◽

Cited By ~ 3

Author(s):

Quan Dai Wang ◽

Ji Ming Xiao ◽

Yan Li

Keyword(s):

Large Scale ◽

Surface Texturing ◽

Friction Reduction ◽

Electrochemical Micromachining ◽

Textured Surface ◽

Reduction Effect ◽

Interacting Surfaces ◽

Etched Surface ◽

Optimized Conditions ◽

Friction Drag Reduction

Surface texturing is a widely accepted approach for friction reduction in mechanical components. Through-mask electrochemical micromachining (EMM) is a simple and reliable process for mass manufacturing of microstructure array on metal surface. However, to obtain engineered surface texture with a prescribed shape, size, orientation, and distribution to investigate how forms and shapes of surface texturing affect the tribological properties on interacting surfaces, the machining conditions still need to be optimized. In this work, the electroetching conditions involving the formulation of the electrolyte, voltage, current density, machining gap and agitation method are optimized. With the optimized conditions, the ordered microstructures with a feature size down to 5m and smooth etched surface in large-scale are obtained and the preliminary friction drag reduction effect of the textured surface is demonstrated.

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Synthesis of [18F]FAZA Using Nosyl and Iodo Precursors for Nucleophilic Radiofluorination

Current Radiopharmaceuticals ◽

10.2174/1874471011666181019105947 ◽

2019 ◽

Vol 12 (1) ◽

pp. 49-57

Author(s):

William Sun ◽

Cheryl Falzon ◽

Ebrahim Naimi ◽

Ali Akbari ◽

Leonard I. Wiebe ◽

...

Keyword(s):

Large Scale ◽

Side Reactions ◽

Automated Synthesis ◽

Complex Reaction ◽

Chemical Structures ◽

Standardized Protocol ◽

High Yields ◽

Automated Procedures ◽

Optimized Conditions ◽

By Products

Background: 1-α-D-(5-Deoxy-5-[18F]fluoroarabinofuranosyl)-2-nitroimidazole ([18F]FAZA) is manufactured by nucleophilic radiofluorination of 1-α-D-(2’,3’-di-O-acetyl-5’-O-toluenesulfonylarabinofuranosyl)- 2-nitroimidazole (DiAcTosAZA) and alkaline deprotection to afford [18F]FAZA. High yields (>60%) under optimized conditions frequently revert to low yields (<20%) in large scale, automated syntheses. Competing side reactions and concomitant complex reaction mixtures contribute to substantial loss of product during HPLC clean-up. Objective: To develop alternative precursors for facile routine clinical manufacture of [18F]FAZA that are compatible with current equipment and automated procedures. Methods: Two new precursors, 1-α-D-(2’,3’-di-O-acetyl-5’-O-(4-nitrobenzene)sulfonyl-arabinofuranosyl)-2- nitroimidazole (DiAcNosAZA) and 1-α-D-(2’,3’-di-O-acetyl-5’-iodo-arabinofuranosyl)-2-nitroimidazole (DiAcIAZA), were synthesized from commercially-available 1-α-D-arabinofuranosyl-2-nitroimidazole (AZA). A commercial automated synthesis unit (ASU) was used to condition F-18 for anhydrous radiofluorination, and to radiofluorinate DiAcNosAZA and DiAcIAZA using the local standardized protocol to manufacture [18F]FAZA from AcTosAZA. Results: DiAcNosAZA was synthesized via two pathways, in recovered yields of 29% and 40%, respectively. The nosylation of 1-α-D-(2’,3’-di-O-acetyl-arabinofuranosyl)-2-nitroimidazole (DiAcAZA) featured a strong competing reaction that afforded 1-α-D-(2’,3’-di-O-acetyl-5’-chloro-arabinofuranosyl)-2- nitroimidazole (DiAcClAZA) in 55% yield. Radiofluorination yields were better from DiAcNosAZA and DiAcIAZA than from DiAcTosAZA, and the presence of fewer side products afforded higher purity [18F]FAZA preparations. Several radioactive and non-radioactive by products of radiofluorination were assigned tentative chemical structures based on co-chromatography with authentic reference compounds. Conclusion: DiAcClAZA, a major side-product in the preparation of DiAcNosAZA, and its deprotected analogue (ClAZA), are unproven hypoxic tissue radiosensitizers. DiAcNosAZA and DiAcIAZA provided good radiofluorination yields in comparison to AcTosAZA and could become preferred [18F]FAZA precursors if the cleaner reactions can be exploited to bypass HPLC purification.

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A facile, inexpensive and green electrochemical sensor for sensitive detection of imidacloprid residue in rice using activated electrodes

Analytical Methods ◽

10.1039/d1ay00984b ◽

2021 ◽

Author(s):

Yitao Lv ◽

Jingming Sun ◽

Sen Qiao ◽

Min Zhang ◽

Juxiu Li

Keyword(s):

Electrochemical Sensor ◽

Large Scale ◽

Cost Effective ◽

Sensitive Detection ◽

Advanced Materials ◽

Electrochemical Activation

The development of sensitive, facile, cost-effective and eco-friendly sensors is essential for monitoring imidacloprid (IDP) residue in large scale. Compared with popular modification of electrodes by advanced materials, electrochemical activation...

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Culture Medium Optimization for Production of Rhamnolipids by Burkholderia glumae

Colloids and Interfaces ◽

10.3390/colloids2040049 ◽

2018 ◽

Vol 2 (4) ◽

pp. 49 ◽

Cited By ~ 4

Author(s):

Arvin Nickzad ◽

Claude Guertin ◽

Eric Déziel

Keyword(s):

Large Scale ◽

Bacterial Species ◽

Potassium Phosphate ◽

Nitrogen Sources ◽

Fractional Factorial ◽

Limiting Factors ◽

Physical Parameters ◽

Scale Production ◽

Burkholderia Glumae ◽

Optimized Conditions

Burkholderia glumae is a biosafety level 1 bacterium capable of producing rhamnolipid biosurfactant with longer 3-hydroxy fatty acid chains moieties than those produced by the prototypal producer, the opportunistic pathogen Pseudomonas aeruginosa. Although the capacity of production of rhamnolipid, and the parameters affecting this production, are well established for P. aeruginosa, little is known about the factors that may affect their production in B. glumae. Hence, to evaluate and enhance the production of rhamnolipids in B. glumae, following the selection of best carbon and nitrogen sources, a two-level fractional factorial design experiment was performed to identify the limiting factors significantly affecting the production of rhamnolipids in this bacterial species. Effects of six inorganic nutrients and two physical parameters were studied, and mannitol, urea, CaCl2, and potassium phosphate buffer were selected for further optimization by applying a response surface methodology (RSM). Under the identified optimized conditions, a rhamnolipid production of 1.66 g/L was obtained, about five times higher than that of the initial non-optimized conditions. This represents a key step in the development of large-scale production processes.

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Flow Battery Electroanalysis 2: Influence of Surface Pretreatment on Fe(III/II) Redox Chemistry at Carbon Electrodes

10.26434/chemrxiv.7125107 ◽

2018 ◽

Author(s):

Tejal Sawant ◽

James McKone

Keyword(s):

Electron Transfer ◽

Photoelectron Spectroscopy ◽

Large Scale ◽

Redox Chemistry ◽

Rotating Disk Electrode ◽

Electrochemical Activation ◽

Carbon Electrodes ◽

Electron Transfer Kinetics ◽

Treatment Protocols ◽

Flow Batteries

Redox flow batteries are attractive for large-scale electrochemical energy storage, but sluggish electron transfer kinetics often limit their overall energy conversion efficiencies. In an effort to improve our understanding of these kinetic limitations in transition metal based flow batteries, we used rotating-disk electrode voltammetry to characterize the electron-transfer rates of the Fe3+/2+ redox couple at glassy carbon electrodes whose surfaces were modified using several pre-treatment protocols. We found that surface activation by electrochemical cycling in H2SO4(aq) electrolyte resulted in the fastest electron-transfer kinetics: j0 = 0:90 mA/cm2 in an electrolyte containing 10 mM total Fe. By contrast, electrodes that were chemically treated to either remove or promote surface oxidation yielded rates that were at least an order of magnitude slower: j0 = 0:07 and 0:08 mA/cm2, respectively. By correlating these findings with X-ray photoelectron spectroscopy data, we conclude that Fe3+/2+ redox chemistry is catalyzed by carbonyl groups whose surface concentrations are increased by electrochemical activation.

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