Single-pot Process Research Articles

Single-pot extractive double divided wall column for Acetonitrile, Ethanol, and water Separation: Design and control

An integrated single-pot double divided wall column (DDWC) process is designed for separating acetonitrile, ethanol and water into its constituent pure components using dimethyl sulfoxide (DMSO) as the homogenous extractive entrainer. Comparison with the recently reported side-stream extractive distillation (SSED) design with three columns shows the single-pot process to be more cost-effective and energy-efficient. The SSED process has a Total Annualized Cost (TAC) that is higher by 9.91% and an energy consumption that is higher by 7.27%. Also, a decentralized temperature inferential control system is shown to effectively reject large throughput and moderate feed composition changes to establish the controllability of the proposed design. The developed single-pot process is thus a promising alternative, particularly for space-constrained production facilities.

Acid-Mediated Domino Cyclization of ortho-Formyl Cinnamate Esters: Synthesis of Substituted Indene/Indane Esters and Indeno[a]indenones.

A Bro̷nsted acid-driven protocol to access substituted monoarylindene esters, biarylindane esters, and indeno[a]indenones from simple ortho-formylcinnamate esters and external arenes has been revealed. Remarkably, this single-pot process enabled the construction of two, three, and four new C-C bonds in building monoarylindene esters, biarylindane esters, and indeno[a]indenones, respectively, under metal-free and mild reaction parameters via triggering the inactive cinnamate ester moiety. In addition, the present strategy is investigated with widespread substrate scope.

Effect of the drying type on the properties of granules and tablets produced by high shear wet granulation

Although high shear mixers can represent a single-pot process, separate drying equipment is commonly employed. Limited literature exists on the use of a heating jacket coupled with a vacuum pump typically used in a single-pot setup, so this study compares the drying effects of a single-pot setup (DSP) and ventilated oven (DVO) on the properties of granules and tablets. Granules containing three actives of varying water solubility were produced and characterised. The results showed that DSP reduced the drying time and produced smaller, irregular, and weaker granules with different compression mechanisms. The tablets were produced and characterised. All tablets passed the uniformity test. Compression differences had no impact on tablet properties for poorly water-soluble actives, but altered properties for highly soluble actives due to increased active migration and crystallization on the granule surface. In conclusion, while DSP offers advantages, careful consideration of the drying technique is essential during product development.

Photo-electrodes decorated with carbon quantum dots: Efficient dye-sensitized solar cells

In this study, the blue and green carbon quantum dots (CQDs) are synthesized and applied to the photo-electrodes of dye-sensitized solar cells (DSSCs). The DSSCs exhibited high power conversion efficiency because of the conversion of ultraviolet to the visible region in photo-anode, and good catalytic activity in the photo-cathode. The blue color CQDs (BCQDs) and green color CQDs (GCQDs) are synthesized from the citric acid in a single pot process. We examine the influence of both CQDs decorated on photo-anode and photo-cathode and both photo-electrodes on the photovoltaic performance of the DSSCs. Furthermore, the DSSCs are studied by electrochemical impedance spectroscopy, cyclic voltammetry, and Tafel polarization data to study the charge transfer kinetics. The better performance observed from the DSSCs due to enhanced charge carrier collection through the CQDs. The photovoltaic results of DSSCs shown that the best efficiency shown by DSSC, which fabricated by both photo-electrodes decorated by CQDs.

The Use of High‐Temperature Semi‐Batch Radical Polymerization to Synthesize Acrylate Based Macromonomers and Structured Copolymers

AbstractA high‐temperature starved‐feed semi‐batch operating policy is developed to produce p(acrylates) with high macromonomer content, taking advantage of side reactions inherent to acrylate radical polymerization. This operating strategy results in significantly higher macromonomer content for the polymerization of isobornyl acrylate (iBoA) versus n‐butyl acrylate (BA) under identical operating conditions. This is because steric hindrance favors fragmentation (i.e., terminal double bond (TDB) formation) over addition (i.e., short‐chain or long‐chain branch (LCB) formation), thus increasing the p(iBoA) TDB content and decreasing polymer dispersity. The p(iBoA) macromonomer solution serves as an excellent addition‐fragmentation agent to polymerize a second monomer in a single pot process controlled by sequential feeding, as demonstrates by the production of iBoA‐BA block and comb copolymer structures at different temperatures and macromonomer concentrations. The incorporation of the p(iBoA) macromonomer into a copolymer product is verified by various techniques, including polymer fractionation followed by TDB, composition, and molar mass analyses. Reaction temperature plays a key role in determining whether a blocky versus comb copolymer structure is produced. The ability to synthesize block and comb copolymers by radical polymerization without a mediating agent offers the potential to efficiently produce structured copolymers for industrial applications.

Modulating the synergy of Pd@Pt core–shell nanodendrites for boosting methanol electrooxidation kinetics

The single-pot production of Pd@Pt core–shell structures is a promising approach as it offers large surface area, catalytic capability, and stability. In this work, we established a single-pot process to produce Pd@Pt core–shell nanodendrites with tunable composition, shape and size for optimal electrochemical activity. Pd@Pt nanodendrites with diverse compositions were synthesized by tuning the ratios of Pd and Pt sources in an aqueous environment using cetyltrimethylammonium chloride, which functioned as both the surfactant and the reducing agent at an elevated temperature (90 °C). The synthesized Pd5@Pt5 nanodendrites showed exceptional electrochemical action toward the methanol oxidation reaction related with another compositional Pd@Pt nanodendrites and conventional Pt/C electrocatalysts. In addition, Pd5@Pt5 nanodendrites exhibited good CO tolerance owing to their surface features and the synergistic effect among Pt and Pd. Meanwhile, nanodendrites with a Pt-rich surface provided exceptional catalytic active sites. Compared with the conventional Pt/C electrocatalyst, the anodic peak current obtained by Pd5@Pt5 nanodendrites was 3.74 and 2.18 times higher in relations of mass and electrochemical active surface area-normalized current density, respectively. This approach offers an attractive strategy to design electrocatalysts with unique structures and outstanding catalytic performance and stability for electrochemical energy conversion.

Improved and ‘Nitrosamines Free’ Process for the Preparation of an α4β2 Neuronal Nicotinic Acetylcholine Receptor Agonist-Varenicline Tartrate

An improvised and efficient approach for synthesis of α4β2 nicotinic acetylcholine receptor subtype agonist, Varenicline tartrate (1) free from the ‘N-nitrosamines’ has been described. The approach involves an improved process for a key intermediate (7,8-dinitro-4,5-dihydro-1H-1,5-methanobenzo[d] azepin-3(2H)-yl)-2,2,2-trifluoro ethanone (7) free from potential genotoxic impurities. Compound 7 is converted into Varenicline base 10 in a single pot process with improved overall yield and quality. Further, Varenicline base 10 is converted into Varenicline tartrate (1) by acid addition salt which provides in quantitative yield. Our improved process consists of technical innovations/improvements which eliminate the probability for the formation of critical impurities such as dinitro nitroso impurity 2, diamino nitroso impurity 3 and varenicline nitroso impurity 4 and other genotoxic impurities such as mono nitro impurity 11 and meta dinitro impurity 12 in the final drug substance and provides ‘Nitrosamines free’ varenicline tartrate (1) with good quality and yield.

Remarkable microwave absorption of GO-SiO2/Fe3O4 via an effective design and optimized composition

We present the design, synthesis, and characterization of the graphene oxide (GO)-SiO2/Fe3O4 nanocomposite as well as its applications for microwave absorption. The GO-SiO2/Fe3O4 nanocomposites were synthesized with three different compositions having mass ratios (1:1), (1:2), and (1:3). Graphene oxide was synthesized by the modified Hummers’ method, while GO-SiO2 was hydrothermally synthesized, and GO-SiO2/Fe3O4 nanocomposites were obtained in a single pot process using different ratios of the mass of magnetite. Various characterization techniques were used to examine carefully the samples. SEM and TEM images show the creation of SiO2 and Fe3O4 nanoparticles on GO layers, which are confirmed by XRD. Next, we studied in detail the microwave absorption properties of all GO-SiO2/Fe3O4 composites. We have verified that GO-SiO2/Fe3O4 (1:3) with a high magnetic saturation of ∼70.5 emu g−1 and a corresponding layer thickness of 2 mm has excellent microwave absorption with a minimum reflection loss of −72.79 dB at 15.87 GHz and an effective absorption bandwidth (less than −10 dB) equal to 2.43 GHz (14.49–16.92 GHz). Besides, the maximum effective bandwidth reaches 7.54 GHz (10.46–18.0 GHz) and 7.39 GHz (10.61–18.0) for thicknesses of 3.2 mm and 3.6 mm in samples (1:2) and (1:1), respectively.

A Bioinspired Strategy for the Enantioselective Synthesis of Bicyclic Oxygen Heterocycles.

A new strategy is described for the direct conversion of unsaturated 3,5-dihydroxy-diarylheptanoids to dimeric products assembled on trans-2,8-dioxabicyclo[4.4.0]decane frameworks. The key atom-economical acid-mediated coupling creates 2 rings and 4 new stereocenters in a single-pot process. Oxygen-18 labeling studies are in accord with reactions proceeding via a cascade mechanism involving carbocationic intermediates. This approach enabled the concise total syntheses of analogues of the natural product blepharocalyxin D in 4 steps from simple starting materials.

Polycyclic Aromatic Hydrocarbons and their Adducts with Solvents from Ag(II)SO4-Based Oxidative C-C Coupling

9,9′-bianthryl and 9,9′-biphenanthryl were synthesized by direct oxidative C–C coupling of anthracene and phenanthrene, respectively, using divalent silver sulfate Ag(II)SO4 under ambient temperature conditions. Syntheses proceed with rather low yields 6–10%, however, they are competitive to more complex synthetic pathways due to single-pot process and lower waste. The single crystal structures of 9,9′-bianthryl, 9,9′-biphenanthryl and adducts of 9,9′-bianthryl with benzene, toluene and o- and p-xylene were obtained. X-ray structure of the adducts attested that the guest molecules of aromatic hydrocarbons were accommodated in cavities formed by the host 9,9′-bianthryl molecule. The adducts are stabilized mostly by the C–H•••π interactions, as indicated by analysis of crystal structures and Hirschfeld surfaces.

Silver nanoparticles synthesized using Allium ampeloprasum L. leaf extract: Characterization and performance in catalytic reduction of 4-nitrophenol and antioxidant activity

A green approach for biosynthesis of silver nanoparticles (AgNPs) is developed using A. ampeloprasum leaf extract. The as-synthesized nanoparticles were characterized by UV–visible, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and zeta sizer (ZS). The formation of AgNPs was confirmed by changing the colour of solution from colourless to light brown and the presence of absorption peaks between 420 and 440 nm using UV spectra. The TEM analysis of AgNPs showed the particle sizes ranged between 2 and 43 nm, with shapes of quasi-spherical, spherical, ellipsoidal, hexagonal and irregular. The crystalline and face centered cubic (FCC) structure of AgNPs was obtained by XRD study. In addition, the FTIR spectrum of AgNPs showed the presence of different functional groups that may be associated with the reduction of Ag ions to AgNPs. The yield of AgNPs was determined around 99.95% by ICP-MS quantification after centrifugal ultrafiltration. The biosynthesized AgNPs exhibited catalytic activity in the reduction of the toxic organic pollutant of 4-nitrophenol to 4-aminophenol, and antioxidant activity against DPPH (2,2-diphenyl-1-picrylhydrzyl) and ABTS+ (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)) radicals. This approach does not require any toxic substance, is quite cheap and readily to be performed in a single pot process.

Complementary effect of thermotolerant yeast and cold active cellulase on simultaneous saccharification and fermentation for bioethanol production from rice straw

The present investigation aimed towards the optimization of bioethanol production from alkali pretreated rice straw using thermotolerant Saccharomyces cerevisiae JRC6 strain which was capable of fermenting glucose at 40 °C with a fermentation efficiency of 91.14%. Four process variables, namely, substrate loading (4.0%–7.0% w/v), enzyme loading (10–30 FPU/g dry rice straw), pH (4.0–6.0), and inoculum rate (7.0%–15.0% v/v), were evaluated by response surface methodology using Box Behnken Design to develop a simultaneous saccharification and fermentation process for bioethanol production using thermotolerant yeast and cold active cellulase cocktail produced by Aspergillus niger SH3. Among these variables, pH was the most significant factor followed by substrate loading. The optimum outcomes of the design were as follows: substrate loading (6.71% w/v), enzyme loading (25.71 FPU/g dry rice straw), pH (4.15), and inoculum rate (13.2% v/v). The validation experiment with the optimized parameters resulted in a better ethanol concentration of 12.95±0.39 g/L within 24 h at 40 °C. The results obtained indicated that the process may further be scaled up as a single pot process with substantial energy saving because the saccharification temperature was 10 °C lower as compared to commercial cellulases, and one step has been reduced due to the combined action of the enzyme and yeast.

Improved and single-pot process for the synthesis of macitentan, an endothelin receptor antagonist, via lithium amide-mediated nucleophilic substitution

An improved, simple, efficient, and telescoped synthesis of macitentan, an endothelin receptor antagonist, starting from 5-(4-bromophenyl)-4,6-dichloropyrimidine in an overall yield of around 62% is described.

Mechanical properties of bulk graphene oxide/poly(acrylic acid)/poly(ethylenimine) ternary polyelectrolyte complex.

Ternary complexes formed in a single pot process through the mixing of cationic (branched polyethylenimine, BPEI) and anionic (graphene oxide, GO, and poly(acrylic acid), PAA) aqueous solutions exhibit superior mechanical performance in comparison to their binary analogs. The composition of the ternary complex can be simply tuned through the composition of the anionic solution, which influences the water content and mechanical properties of the complex. Increasing the PAA content in the complex decreases the overall water content due to improved charge compensation with the BPEI, but this change also significantly improves the toughness of the complex. Ternary complexes containing ≤32 wt% PAA were too brittle to generate samples for tensile measurements, while extension in excess of 250% could be reached with 57 wt% PAA. From this work, the influence of GO and PAA on the mechanical properties of GO/PAA/BPEI complexes were elucidated with GO sheets acting to restrain the viscous flow and improve the mechanical strength at low loading (<12.6 wt%) and PAA more efficiently complexes with BPEI than GO to generate a less swollen and stronger network. This combination overcomes the brittle nature of GO-BPEI complexes and viscous creep of PAA-BPEI complexes. Ternary nanocomposite complexes appear to provide an effective route to toughen and strengthen bulk polyelectrolyte complexes.

Study of the influence of coating methods on lipid spheres manufactured on rotor fluidized bed process

Different previous works have shown that various kinds of spheres can be manufactured by rotor granulation in a ‘single-pot process’ using a lipid base: hydrogenated castor oil. This single-pot technology is based on wet granulation where all components are placed in the powder form in the rotor bowl; then, they are continuously suspended in a fluidized air, with a tangentially sprayed liquid solution. This process allows the granulation and manufacturing of sphere during the same time. Previous experiments have studied the influence of the formulation and the manufacturing process parameters on spheres in terms of feasibility and dissolution properties. Both the spraying time and the weight of liquid sprayed were found to be the most relevant parameters that govern the final quality of the sphere. Now, in a second part of the work, a first comparison is made with two different fluid bed methods: the tangential rotor spray and the Wurster bottom spray for coating the lipid spheres previously manufactured with the rotor tangential spray. The external aspect of the coated spheres manufactured has been evaluated with an electronic microscopy analysis and a study of dissolution properties of the active ingredient has been done by USP in vitro dissolution tests.

Biosynthesis of gold nanoparticles using Capsicum annuum var. grossum pulp extract and its catalytic activity

Biological synthesis approach has been regarded as a green, eco-friendly and cost effective method for nanoparticles preparation without any toxic solvents and hazardous bi-products during the process. This present study reported a facile and rapid biosynthesis method for gold nanoparticles (GNPs) from Capsicum annuum var. grossum pulp extract in a single-pot process. The aqueous pulp extract was used as biotic reducing agent for gold nanoparticle growing. Various shapes (triangle, hexagonal, and quasi-spherical shapes) were observed within range of 6–37nm. The UV–Vis spectra showed surface plasmon resonance (SPR) peak for the formed GNPs at 560nm after 10min incubation at room temperature. The possible influences of extract amount, gold ion concentration, incubation time, reaction temperature and solution pH were evaluated to obtain the optimized synthesis conditions. The effects of the experimental factors on NPs synthesis process were also discussed. The produced gold nanoparticles were characterized by transform electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDS) and Fourier Transform infrared spectroscopy (FTIR). The results demonstrated that the as-obtained GNPs were well dispersed and stable with good catalytic activity. Biomolecules in the aqueous extract were responsible for the capping and stabilization of GNPs.

Production of Ionic Liquid Tolerant Cellulase from Bacillus subtilis G2 Using Agroindustrial Residues with Application Potential for Saccharification of Biomass Under One Pot Consolidated Bioprocess

Ionic liquid (IL) based pretreatment of lignocellulosic biomass for facilitating efficient enzymatic saccharification has emerged as an environmentally benign approach that offers several advantages over conventional strategies. However, residues of ionic liquid left in the pretreated biomass may cause inactivation of saccharifying enzymes thus, necessitating the requirement of ionic liquid-stable enzymes. Cost-effective production of industrial enzymes is always desired to enhance the overall process economy. Current study reports IL-stable cellulase production from a newly isolated bacterium Bacillus subtilis G2. Design of experiment (DoE) based on response surface methodology was used in sequential manner for optimizing cultural and environmental variables to enhance cellulase production by 2.66-fold. IL-stable cellulase was used for saccharification of IL-pretreated pine needle biomass (PNB) with 1-ethyl-3-methylimidazolium methanesulfonate in a consolidated single pot process i.e. one pot consolidated bioprocess (OPCB). The saccharification efficiency of 23.57 % was observed under OPCB. The hydrolsate obtained was fermented by dual culture of yeast i.e. Saccharomyces cereviasie NCIM 3078 and Pichia stipitis NCIM 3497, and a yield of 0.092 g ethanol/g of PNB was obtained with fermentation efficiency of 25.62 %. This study is first ever where-in IL-stable cellulase production is accomplished using agroindustrial residues by employing DoE, and assessed for its application potential under OPCB for saccharification of IL-pretreated PNB. IL-stable cellulases would not only preclude expensive washing step following IL-pretreatment of biomass, but their application in a consolidated single pot process (OPCB) offers numerous technoeconomic advantages over conventional multi pot processes. Production of ionic liquid (IL) tolerant cellulase from Bacillus subtilis G2 was enhanced by 2.66-fold using response surface methodology. Cellulase was assessed for its saccharification potential on IL-pretreated pine needle biomass under one pot consolidated bioprocess, and the hydrolysate was fermented to ethanol using Saccharomyces cereviasie and Pichia stipitis.

Synthesis and Characterization of Eu3+-Doped CdS Quantum Dots by a Single-Step Aqueous Method

Eu3+-doped CdS quantum dots (QDs) are successfully synthesized through a straightforward single-pot process in aqueous solution using thioglycolic acid as the capping ligand. The structure, shape, and spectral properties of the QDs are investigated. The obtained CdS:Eu3+ QDs exhibit cubic structures with good crystallinity and approximately sphere-like shapes about 4 nm in diameter. The CdS QDs manifest a broadband emission peak at 600 nm and enhanced Photoluminescence (PL) emission intensity after doping with Eu3+ ions. Given the strong PL intensity and good chromaticity of the sulfide-based QDs, they have potential use in doping rare-earth ions.

Bio-synthesis and characterization of silver nanoparticles using Terminalia chebula leaf extract and evaluation of its antimicrobial potential

Due to increasing global conflicts, there is an emergent need to develop environmentally benign nanoparticles without the use of toxic chemicals. The bio-synthesis of silver nanoparticles (SNPs) using Terminalia chebula (TC) leaf extract becomes one of the more potential areas of research. The bio-reduction of metal ions is quite rapid and readily to be performed at room temperature. Present study describes a rapid and eco-friendly synthesis of TC-SNPs using TC leaf extract in a single pot process and is observed when the medium changes to brown color with the addition of silver ion. The obtained results confirmed that recorded UV spectra shows the characteristic surface plasmon resonance band for TC-SNPs in the range of 400–440nm. Anti-bacterial activity of bio-synthesized TC-SNPs shows effective inhibition against human pathogens including, Bacillus subtilis (ATCC 6633) and Escherichia coli (ATCC 25922). Thus, the significant outcome of this study would help to formulate value added herbal based on nano-materials in biomedical and nanotechnology industries.

Biological synthesis and characterization of silver nanoparticles using Eclipta alba leaf extract and evaluation of its cytotoxic and antimicrobial potential

With increasing global competitions there is a growing need to develop environmentally benevolent nanoparticles without the use of toxic chemicals. The biosynthesis of silver nanoparticles (AgNPs) using plant extracts became one of the potential areas of research. The bioreduction of metal ion is quite rapid, readily perform at room temperature and easily scale up. The present study describes a rapid and eco-friendly synthesis of AgNPs using Eclipta alba plant extract in a single pot process. The efficiency and the influence of various process variables in the biosynthesis of AgNPs analysed include redundant concentration, temperature and time. AgNPs were rapidly synthesized using aqueous leaf extract of E. alba and was observed when the medium turned to brown colour with the addition of silver ion. Biosynthesized AgNPs were characterized by the help of UV–visible spectroscopy for their stability and physicochemical parameters were studied by dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy. The obtained results confirmed that recorded UV spectra show the characteristic surface plasmon resonance band for AgNPs in the range of 400–440 nm and physiochemical structural analysis shown that obtained AgNPs were crystalline in nature. Further, cytotoxic and antimicrobial activities of biosynthesized AgNPs against RAW 254.7, MCF-7 and Caco-2 cells as well as Gram positive and Gram negative bacteria were assessed. In-vitro cytotoxicity activity of characterized AgNPs against tested cell lines showed significant anti-cell-proliferation effect in nanomolar concentrations. The antibacterial activity of synthesized AgNPs showed effective inhibitory activity against human pathogens, including, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Thus, the significant outcome of this study would help to formulate value added herbal-based nano-materials in biomedical and nanotechnology industries.