Ethanolic Ammonia Research Articles

One-step synthesis of TiO2/Fe3O4/C hydrophilic magnetic nanocomposites using the magnetized submerged arc discharge method

This study investigates the production of TiO2/Fe3O4/C hydrophilic magnetic nanocomposites produced via a one-step novel method using the submerged arc discharge method applied in liquid media of ethanol and ethanol–ammonia under the influence of external magnetic field. The magnetized submerged arc discharge forms a longer-lasting plasma arc, thereby affecting the growth of spherical and tubular carbon nanocomposites. More reactive species enrolled in the carbon growth in the magnetized submerged arc discharge, resulting in the ordered crystalline structure. The nanocomposites synthesized in ethanol–ammonia show hydrophilic characteristics, indicated by their dispersion improvement in the water and the presence of the vibrations of hydroxyl, amine, and –CN functional groups in Fourier transfer infrared (FTIR) spectra. The preparation technique described in this study using magnetized submerged arc discharge is supposed to be a simple and less costly preparation method that can potentially be further applied to produce numerous other nanocomposites.

Novel green HPTLC and organic solvent-free micellar LC methods for the simultaneous determination of Ozenoxacin and benzoic acid; greenness assessment and applications

Ozenoxacin (OZ) is a novel synthetic quinolone antimicrobial agent that has been recently approved by US-FDA for the treatment of impetigo in combination with its preservative, benzoic acid (BA). Meanwhile, implementing greener chromatography has been a recent goal of a great ecological importance. In the proposed research, two novel green methods have been validated for the simultaneous determination of OZ and BA in skin creams for the first time. An organic-solvent free mixed-micellar HPLC technique was developed using RP-C8 core-shell column with a mobile phase consisting of 0.01 M Brij-35, 0.15 M sodium dodecyl sulfate, and 0.02 M ammonium acetate in water, adjusted to pH 4.5. The mobile phase flow rate was 1 mL min−1 and detecting analytes in short retention times (3.4 and 4.7 min for BA and OZ, respectively) at wavelength 235 nm. The working concentration ranges were 1–10 and 10–100 μg mL−1 for BA and OZ, respectively. Another eco-friendly high-performance thin-layer chromatography (HPTLC) method was designed using HPTLC silica-gel 60 F254 plates as a stationary phase and ethyl acetate–ethanol–ammonia (6:4:2, v/v/v) as mobile phase. The detection was also performed at λmax = 235 nm. The method was found linear across concentration range of 0.5–1.8 and 0.05–0.18 μg/band for OZ and BA, respectively which gave symmetric, compact band with Rf values of 0.21 and 0.69 for OZ and BA, respectively. The proposed methods were applied successfully in their combined marketed pharmaceutical cream. The proposed methods were typically based on safe biodegradable reagents, and their ecological superiority was proven using recent greenness metrics.

Use of TLC-Densitometric Method for Determination of Valproic Acid in Capsules.

Determination of valproic acid in the drug was carried out on the aluminum silica gel 60F254 plates and using acetone–water–chloroform–ethanol–ammonia at a volume ratio of 30:1:8:5:11 as the mobile phase, respectively. Two methods of detection of valproic acid were used. The first was a 2% aqueous CuSO4×5H2O solution, and the second was a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system. The applied TLC-densitometric method is selective, linear, accurate, precise, and robust, regardless of the visualizing reagent used for the determination of valproic acid in Convulex capsules. It has low limits of detection (LOD) and limits of quantification (LOQ), which are equal to 5.8 μg/spot and 17.4 μg/spot using a 2% aqueous CuSO4×5H2O solution as visualizing agent and also 0.32 μg/spot and 0.97 μg/spot using a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system as visualizing reagent, respectively. The described analytical method can additionally be used to study the identity of valproic acid in a pharmaceutical preparation. The linearity range was found to be 20.00–80.00 μg/spot and 1.00–2.00 μg/spot for valproic acid detected on chromatographic plates using a 2% aqueous CuSO4×5H2O solution and the 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system, respectively. A coefficient of variation that was less than 3% confirms the satisfactory accuracy and precision of the proposed method. The results of the assay of valproic acid equal 96.2% and 97.0% in relation to the label claim that valproic acid fulfill pharmacopoeial requirements. The developed TLC-densitometric method can be suitable for the routine analysis of valproic acid in pharmaceutical formulations. The proposed TLC-densitometry may be an alternative method to the modern high-performance liquid chromatography and square wave voltammetry in the control of above-mentioned substances, and it can be applied when other analytical techniques is not affordable in the laboratory.

Reduction of autofluorescence in whole adult worms of Schistosoma japonicum for immunofluorescence assay

Immunofluorescence assay is one of methods to understand the spatial biology by visualizing localization of biomolecules in cells and tissues. Autofluorescence, as a common phenomenon in organisms, is a background signal interfering the immunolocalization assay of schistosome biomolecules, and may lead to misinterpretation of the biomolecular function. However, applicable method for reducing the autofluorescence in Schistosoma remains unclear. In order to find a suitable method for reducing autofluorescence of schistosomes, different chemical reagents, such as Sudan black B (SBB), trypan blue (TB), copper sulfate (CuSO4), Tris-glycine (Gly), and ammonia/ethanol (AE), at different concentrations and treatment time were tested, and SBB and CuSO4 were verified for the effect of blocking autofluorescence in immunofluorescence to localize the target with anti-SjCRT antibody. By comparing the autofluorescence characteristics of different conditions, it was found that SBB, TB and CuSO4 had a certain degree of reducing autofluorescence effect, and the best effect in females was using 50 mM CuSO4 for 6 h and in males was 0.5% SBB for 6 h. Furthermore, we have applied the optimized conditions to the immunofluorescence of SjCRT protein, and the results revealed that the immunofluorescence signal of SjCRT was clearly visible without autofluorescence interference. We present an effective method to reduce autofluorescence in male and female worm of Schistosoma japonicum for immunofluorescence assay, which could be helpful to better understand biomolecular functions. Our method provides an idea for immunofluorescence assay in other flukes with autofluoresence.

Ethanolic ammonia pretreatment for efficient biogas production from sugarcane bagasse

Sugarcane bagasse (SCB), as an abundant lignocellulosic waste, was subjected to ethanolic ammonia pretreatment followed by anaerobic digestion to produce biogas. Ammonia pretreatment was performed with 10% v/v aqueous ammonia solution at 50 and 70 °C for 12 and 24 h. Furthermore, the effect of addition of ethanol to the pretreatment mixture at different concentrations (5, 25, and 50% v/v) was investigated. Two scenarios for biogas production from SCB were considered and compared in terms of equivalent gasoline production per unit mass of biomass: (1) biogas production from the pretreatment separated solid and liquid fractions, and (2) biogas production from the whole pretreatment slurry. The highest methane yield of 298.0, 248.6, and 299.3 ml/g VS (volatile solids) were attained from the liquid fraction, solid fraction, and the whole slurry of pretreatment at 70 °C, respectively. Whereas, methane yield from untreated SCB was only 105.6 ml/g VS. Generally, the methane production yield by pretreatments at 70 °C was more than those at 50 °C. The maximum equivalent gasoline from each ton of SCB for scenarios 1 and 2 were 172 and 182 L, respectively, obtained after pretreatment at 70 °C for 12 h with 10% ammonia +50% ethanol, whereas it was 103 L from untreated SCB.

Access to silver-NHC complexes from soluble silver species in aqueous or ethanolic ammonia

In this communication, we report the use of aqueous ammonia as original conditions for the metalation of imidazol(in)ium ligands. This reaction, performed in homogenous conditions via a soluble silver-ammine complex is a rapid, scalable and often efficient access to silver-NHC complexes. Moreover, modification of the reported reaction conditions allowed the preparation of unprecedented heteroleptic NHC-Ag-phosphine in case of bulky IPr and SIPr ligands.

A comparative study of alkaloids of root extract of Melilotus alba (l) and Psoralea corylifolia

The present communication deals with a comparative study of alkaloids of root extract in two species i.e Melilotus alba L. and Psoralea corylifolia L . Alkaloids are basic nitrogenous secondary plant products possessing heterocyclic compounds as their structural units with a pronounced physiological action. Alkaloids of Melilotus alba L. and Psoralea corylifolia L. may be useful for various diseases like piles, syphilis, gonorrhea, urine flow, menstruation trouble and kidney disorder. Descending paper chromatography on whatman’s paper­­-1 and three solvent system were used, viz. n-butyl acetate, acetic acid –n-butanol–water (85:40:15:22, solvent-1), n-butanol-acetic acid water (4:1:2 solvent-2) and ethanol–ammonia (4:1 solvent-3). Result revealed that six alkaloids viz N-dimethyle, tryptamine, Nb-oxide, hordenine, candicine, β-phenyle thylamine and hypaphorine were detected in both Melilotus alba L. and Psoralea corylifolia L .

Fabrication of mesoporous spherical silica nanoparticles and effects of synthesis conditions on particle mesostructure

Despite the great progress in the field of mesoporous silica materials, there are few reports on mesoporous spherical silica nanoparticles (MSSNPs) synthesized by hydrolysis and co-condensation of tetraethyl orthosilicate (TEOS) and n-octadecyltrimethoxysilane (C18TMS). Here, we design a facile strategy for the synthesis of MSSNPs using C18TMS as a porogen, and TEOS as a silica precursor in a water–ethanol–ammonia system. Further, we investigate the effects of some synthesis conditions, including synthesis time, reaction temperature and molar ratio of EtOH/H2O on mesostructure. The obtained particles show tunable pore diameter, pore volume and surface area by changing synthesis conditions. Electron microscopy images show a particle size ranging from 100nm to 200nm. The N2 adsorption analysis indicates that the maximum Brunauer–Emmett–Teller surface area and Barrett–Joyner–Halanda pore volume up to 1164.9m2g−1 and 1.5cm3g−1 respectively, and a maximum pore diameter of 4.9nm.

An evaluation of selective deprotection conditions for the synthesis of RNA on a light labile solid support

We have investigated the cleavage rates of various protecting groups for the exocyclic amine of cytosine, adenine, and guanine bases. Specifically, deprotection of N-benzoyl (Bz), N-acetyl (Ac), N-isobutyryl (iBu), N-phenoxyacetyl (PAC) and N-tert-butylphenoxyacetyl (tBPAC) groups from 2′-deoxyribonucleosides was effected under various cleavage conditions and the rates of cleavage (half-lives) were determined. Aqueous methylamine cleaves all of the examined protecting groups from the exocyclic amine the fastest among the six methods used. Ethanolic ammonia showed the highest selectivity between standard protecting groups (Ac, Bz, iBu) and fast-deprotecting groups (PAC, tBPAC). Under ammonia conditions, it was possible to cleave PAC and tBPAC rapidly and selectively in 2h, while still retaining the large majority of the acetyl, benzoyl and isobutyryl groups. The results of this study allowed us to perform mild and complete deprotection of an oligoribonucleotide while still attached to the support with a light labile linker. This procedure simplifies and speeds up post-synthesis processing of the RNA chain and offers a new route to the synthesis of sensitive oligonucleotide derivatives on solid supports.

Technology selection for bioethanol production: supply chain perspective

There is a large body of literatures regarding the choice and optimization of different processes for bioethanol and bio-commodities production. However, most of these works are focusing either on single unit of operation or single conversion facility. As these operations are heavily related, it is essential to consider all of them at the supply chain level. In this work, an optimization model for biomass to ethanol supply chain is developed, which takes into account economics and environments as primary objectives. The developed model is used to compare the efficiency of several pre-treatment methods: Dilute-Sulphuric acid, Organosolv and Soaking in Ethanol and Aqueous Ammonia pre-treatment methods, together with Thermochemical conversion in Minnesota, USA. It can be concluded that currently, Dilute-Sulphuric acid pre- treatment is still the most profitable method for ethanol production. However, Organosolv pre-treatment process is the most promising technology accessed since it captures most of the lignin present in the feedstock, which is a significant source of CO 2 emission if sent for combustion. We believe that the future of technology selection for biomass conversion should be focusing on the holistic view of the entire supply chain, and our approach represents a dependable way to obtain the required results.

Nickel(II) complexes with nitrogen-containing derivatives of the closo-decaborate anion

The reactions of the salt (Bu4N)[2-B10H9O2C4H8] (1) with ammonia and ethylenediamine in ethanol were studied. These reactions afford substituted closo-decaborates with nitrogencontaining groups linked to the cluster through a diethylene glycol spacer. Using this method, we synthesized derivatives of the closo-decaborate anion with the pendant groups -NH3+ and -NHCH2CH2NH2; the complexes [Ni(H2O)(en)(L)] (7) and [Ni(en)(L)]·0.5H2O (8), where L = [2-B10H9O(CH2)2O(CH2)2NH(CH2)2NH2]2−, were synthesized. The X-ray diffraction study showed that the coordination sphere of the Ni2+ ions in complexes 7 and 8 have the same composition (4 N + 2 O). However, the coordination environment differs in the nature of the oxygen atom. Thus the oxygen atom directly bonded to the boron cluster is involved in the coordination of the metal ion in compound 8, whereas a water molecule is involved in the coordination in compound 7.

Sol–gel synthesis of MCM-41 silicas and selective vapor-phase modification of their surface

Silica particles with uniform hexagonal mesopore architecture were synthesized by template directed sol–gel condensation of tetraethoxysilane or mixture of tetraethoxysilane and (3-chloropropyl)triethoxysilane in a water–ethanol–ammonia solution. Selective functionalization of exterior surface of parent materials was carried out by postsynthetic treatment of template-filled MCM-41 and Cl-MCM-41 with vapors of (3-chloropropyl)triethoxysilane and 1,2-ethylenediamine in vacuum. The chemical composition of obtained mesoporous silicas was estimated by IR spectroscopy and chemical analysis of surface products of reactions. Characteristics of porous structure of resulting materials were determined from the data of X-ray, low-temperature nitrogen ad-desorption and transmission electron microscopy measurements. Obtained results confirm invariability of highly ordered mesoporous structure of MCM-41 and Cl-MCM-41 after their selective postsynthetic modification in vapor phase. It was proved that proposed method of vapor-phase functionalization of template-filled starting materials is not accompanied by dissolution of the template and chemical modification of pores surface. This provides preferential localization of grafted functional groups onto the exterior surface of mesoporous silicas.

Hydrophobic Flexible Silica Aerogels Felts Fabricated by Ambient Pressure Drying

Hydrophobic flexible silica aerogels felts were fabricated successfully by two-steps sol-gel process via ambient pressure drying. First of all, the sol with various pH values was obtained from tetraethylorthosilicate (TEOS) as silicon source, hydrochloric acid/aqueous ammonia ethanol solution as catalysts. Then glass fiber felts was incorporated into the sol to increase the mechanical properties of silica aerogel. After the completion of solvent exchange and surface modification by using trimethylchlorosilane (TMCS)/n-hexane solution, the gel felts were dried under ambient pressure. The samples show excellent hydrophobic properties.

Synthesis and crystal structure of {Ru2(CO)6-μ2-η3-[(Ph)CC(H)C(H)NC(H)C(H)C(H)(Ph)]} — The first structurally characterized iminoallyl ruthenium carbonyl complex

The dinuclear ruthenium carbonyl cluster {Ru 2 (CO) 6 -μ 2 -η 3 -[(Ph)C C(H) C(H) N C(H) C(H) C(H)(Ph)]} is produced from the reaction of cinnamaldehyde and Ru 3 (CO) 12 in a 2.0 M solution of ammonia in ethanol. From the crystal structure it gets obvious that ammonia reacted with two molecules of cinnamaldehyde. The resulting ligand may best be described as a formally dianionic ruthenium coordinated imino-allyl-system with one exocyclic 3-phenylallylidene unit that shows no interaction with the transition metals whereas the second one is bound to ruthenium via a C H activation step in γ-position with respect to the nitrogen atom.

A performance study of enhanced visible-light-driven photocatalysis and magnetical protein separation of multifunctional yolk–shell nanostructures

Synthesis of functional yolk–shell nanostructures (YSNs) containing SiO2 nanoparticle yolk and a mesoporous shell of NiTiO3 is reported. SiO2@TiO2 core–shell spheres were first prepared via a sol–gel approach, and then a Ni(OH)2 nanowhisker was deposited on the surface of a TiO2 layer and SiO2 nanoparticle-core etching took place simultaneously in a H2O–ethanol–ammonia solution reaction, and then a SiO2@void@TiO2@Ni(OH)2 structure was obtained. Finally, the TiO2@Ni(OH)2 shell was transformed into the NiTiO3 shell via calcination treatment, and the SiO2@NiTiO3 YSNs were achieved. The chemical composition and photoresponsive properties of the SiO2@NiTiO3 yolk–shell material can be easily tailored by adjusting the molar ratio of the Ni/Ti precursors. Their visible-light-induced photocatalytic activities were evaluated by the degradation of methylene blue. The SiO2@NiTiO3 YSNs exhibited enhanced and stable photocatalytic performance due to the unique yolk–shell structure, large surface area, fast diffusion of reactants, and multiple reflections of visible light within the sphere interior voids. Furthermore, the present synthesis method can be extended to the preparation of other functional YSNs, such as magnetic YSNs consisting of SiO2-coated Fe3O4 yolk and a Ni(OH)2-coated TiO2 shell, for the application of magnetic separation of proteins.

Determination of seven synthetic dyes in animal feeds and meat by high performance liquid chromatography with diode array and tandem mass detectors

An efficient method was developed for the simultaneous determination of seven commonly used synthetic sulfonate dyes (Ponceau 4RC, Sunset yellow, Allura red, Azophloxine, Ponceau xylidine, Erythrosine and Orange II) in animal feed and meat using high performance liquid chromatography (HPLC-DAD) and tandem mass spectrometry (HPLC–MS/MS). Ethanol–ammonia–water (80:1:19, V/V/V) solution was used as extract solution, which can extract target species while reducing interference from the sample matrices. The recoveries of these 7 dyes in animal feed and chicken meat were between 71% and 97% with relative standard deviations less than 14.8%. HPLC–MS/MS was employed as a further means of confirmation to assure accuracy of the results. Limits of detection for these dyes were in the range of 0.02–21.83ngmL−1. The proposed method can be applied to confirmative screening of seven commonly used food colorants in feed and meat samples.

A novel strain of Actinopolyspora mortivallis with antibacterial activity isolated from a Saharan soil

A new halophilic actinomycete strain, designated H16, has been isolated from a hypersaline Saharan soil in Ouargla province (southern Algeria) and characterized taxonomically using a polyphasic approach. The strain grew at 18–50°C, pH 5–9, and 7–32% (w/v) NaCl. It produced abundant aerial mycelia, which formed long chains of rod-shaped spores at maturity, and fragmented substrate mycelia. The strain contained chemotaxonomic markers that were diagnostic for the genus Actinopolyspora, such as meso-diaminopimelic acid, arabinose, and galactose, phosphatidylcholine as a diagnostic phospholipid, and predominant menaquinones MK-9(H4) and MK-10(H4). The predominant fatty acids were anteiso- and iso-C17:0, iso-C15:0, and 9-methyl-C16:0. Phylogenetic analysis, based on 16S rDNA gene sequences, confirmed that strain H16 is a member of the genus Actinopolyspora and most closely related to A. mortivallis (98.7% identity). DNA–DNA hybridization confirmed that it belonged to A. mortivallis. This strain showed high activity against Klebsiella pneumoniae and optimally secreted antibiotics during the mid-stationary growth phase in liquid culture. The antibiotics were extracted with n-butanol and separated on silica gel plates by ethanol–ammonia–water (mobile phase). The results of bioautography revealed the presence of five antibiotics. The chemical revelations showed that these antibiotics were glycosylated polycyclic aromatic compounds containing amine groups and hydroxamic acids. The UV-visible and mass spectra of the most active antibiotics were determined.

Measurement and Correlation of the Solubility of Ammonia in Ethanol between 277.35 and 318.25 K

The solubility of ammonia in ethanol was measured by a static−analytic method. The total pressure is up to about 0.4 MPa, and temperature ranges from (277.35 to 318.25) K. The relationship between the partial molar volume of ammonia infinitely diluted in ethanol and temperature is obtained by measuring the density of (ethanol + ammonia) solution. The experimental results are used to determine the (molality scale based) Henry’s constant of ammonia in ethanol, where the activity in the liquid phase is calculated by applying the molality scale based Gibbs excess energy model of Pitzer.

Synthesis of 3-substituted benzo[ g]isoquinoline-5,10-diones: a convenient one-pot Sonogashira coupling/iminoannulation procedure

A series of 3-substituted 5,10-dimethoxybenzo[ g]isoquinolines were prepared by coupling of terminal alkynes with the tert-butylimine of 3-bromo-1,4-dimethoxy-2-naphthaldehyde in the presence of a Pd-catalyst and subsequent Cu-catalyzed cyclization of the intermediate 3-alkynyl-2-naphthylcarbaldehyde. A CAN-mediated oxidative demethylation yielded the corresponding 2-azaanthraquinones in excellent yields. Since this methodology proved to be limited to alkynes bearing aromatic groups, an alternative and more general Pd-catalyzed coupling procedure was developed, starting from 3-bromo-1,4-dimethoxy-2-naphthaldehyde. For more acidic terminal alkynes, like phenylacetylene, a combination of Pd(OAc) 2/P( t-Bu) 3/CuI (2/6/1) with potassium carbonate in DMF gave a complete conversion within 24 h. For less acidic acetylenes, 2 equiv of alkyne and caesium carbonate as a base were required in order to obtain complete conversion of the starting material within 24 h. These altered Sonogashira conditions also allowed the isolation of a benzo[ f]indenone as an interesting side product in case Bu 4NCl was added to the reaction mixture. The 3-alkynyl-1,4-dimethoxy-2-naphthaldehyde acquired after completion of the Pd-catalyzed coupling could be cyclized by adding a solution of ethanolic ammonia and an extra equivalent of potassium carbonate to the reaction mixture. As such, this consecutive one-pot coupling/iminoannulation procedure was a convenient alternative to the Larock isoquinoline procedure, enabling the isolation of a series of 3-substituted 5,10-dimethoxybenzo[ g]isoquinolines.

The Solubility of ammonia in ethanol between 277.35 K and 328.15 K

The solubility of ammonia in ethanol has been measured by a static vapor–liquid equilibrium method. The total pressure ranges up to about 0.72 MPa. The temperature amounts to 277.35, 288.65, 298.15, 308.75, 318.25 and 328.15 K. The experimental results are used to determine Henry's law constant. From their variation with temperature, the average absolute relative deviation of the Henry's law constant from appropriate smoothing equation is 4.42%.