Compounds In Aqueous Media Research Articles

Обеспеченность макроэлементами питания и прогнозирование урожайности яровой пшеницы в Республике Татарстан

The article examines the possibility of forecasting the spring wheat the productivity according to the content of mobile forms of phosphorus, potassium, applied amount of mineral and organic fertilizers. Deviation of the projected yield from actual comes to 31%, and the forecasting yield of the moving average drops to 4.6%. During the observation period the spring wheat productivity increased from 11.6 to 18.7 kilogram per hectare, an increase was 7.1 tons per hectare with an average yield of 17.4 tons per hectare. The productivity of spring wheat exhibits a very unstable value, which is evidenced by the high variation coefficient - 43.3%. There is a positive correlation between security soil by phosphorus, potassium and spring wheat yield. It is positive according to phosphorus for the actual and derivative wheat yield, the higher rates of coefficients was according U11. Potassium also has a positive association with yield. However, the correlation coefficients of potassium are higher (0.57-0.0.94), than of phosphorus (0.50-0.84). This fact suggests, that potassium in macroelement is more scarce, than phosphorus. Apparently, this feature of mobile potassium is manifested by solubility characteristics of the potassium compounds in aqueous medium, despite a sufficient amount of its gross shapes in soils. Studies prove once again, that the basis of of productivity formation is security by nutrient macroelements and peculiarities of economic activities. In addition to more accurately actual spring wheat yield it is necessary to attract agro-climatic indicators. The projections data are also a good tool for assessing the economic activity of individual districts, regions, and land users of different levels.

Synthesis of various heterocyclic compounds via multi-component reactions in water

Due to special effects of water such as abundant, environmentally benign, hydrogen bonding in the transition state and high cohesive energy density as well as negative activation volume; the use of water as a green solvent is emphasized in green chemical processes. Heterocyclic compounds play an important role in the treatment of many diseases and also are effective in biological processes. Multi-component reactions are powerful synthetic methods in construction of new organic molecules because in these methods product is formed as one-pot and reduced number of reaction separation steps. For these reasons, the synthesis of heterocyclic systems using a simple multi-component approach in water is investigated greatly in the recent years. In this review, multi-component reactions that have been used for the synthesis of heterocyclic compounds in aqueous media during the last two decades are described.

Isomerization and Alkylation of Biomass-Derived Compounds in Aqueous Media over Hydrophobic Solid Acid Catalysts: A Mini Review

Isomerization and alkylation of biomass-derived compounds are key industrial processes for mitigating over dependence on fossil fuels and petrochemicals. Although designing the reactions in aqueous media is environmentally sustainable, cost-effective, and efficient, the most reliable catalysts are still being sought. We have therefore reviewed and analyzed classified literature on the prospects of hydrophobic zeolites, acidic oxides, and heteropoly acid catalysts. Emphasis was given to catalyst design, key active sites, modification, catalytic activity in related reactions, and stability properties.

Rapid and Simultaneous Determination of Volatile Fatty Acids and Indoles in Pig Slurry and Dog Excrement by Solid-Phase Micro-Extraction Method with Gas Chromatography

A rapid and simple method for the quantitative determination of volatile fatty acids (VFAs; propionic acid, n-butyric acid, i-valeric acid and n-valeric acid) and indoles (phenol, p-cresol, 4-ethyl phenol, indole and skatole) in pig slurry and dog excrement using solid-phase micro-extraction (SPME) coupled to gas chromatography was evaluated. 50/30 ㎛ DVB/CAR/PDMS (Divinylbenzene/Carboxen/Polydimethylsiloxane) fiber was used to extract the target compounds in aqueous media. Sample amount and adsorption time was standardized for the routine analysis. Detection limits were from 0.11 to 0.15 ㎍/L for VFAs and from 0.12 to 0.28 ㎍/L for indoles and the correlations observed (R2) were 0.975～1.000. This method was applied to the pig slurry, fertilizer, compost and dog excrement. In nearly all cases, the indoles were detected in concentrations of higher than their limits of detection (DOLs). But the VFAs in swine manure were below their DOLs.

Photoactive chitosan: a step toward a green strategy for pollutant degradation.

This article is a highlight of the paper by Ferrari etal. in this issue of Photochemistry and Photobiology. It describes the innovative use of rose bengal-conjugated chitosan as a reusable green catalyst that photo-degrades phenolic compounds in aqueous media, and thereby has decontamination potential of polluted waters. Whether a next-generation photoactive polymer that produces singlet oxygen is a solution to pollutant degradation can be argued. It is as yet unclear what polymeric sensitizer would be practical on a large scale. Nonetheless pursuing this goal is worthwhile.

Facile synthesis of new sodium alginate–anthracene based photosensitizers

Facile syntheses of water-soluble sodium alginate (Na-Alg) derivatives employing anthracene moieties (Anth) have been carried out. Na-Alg amide (Alg-Anth amide), and Na-alg ester (Alg-Anth ester) derivatives were synthesized using 2-amino anthracene and 9-chloromethyl anthracene (9-CMA), respectively. These polymeric materials were characterized (FTIR, 13C NMR, GPC, UV–Vis and fluorescence spectroscopy). These derivatives were photoactive and demonstrated photosensitizing capabilities in presence of an acceptor pyrene. Alg-Anth ester was more efficient (63 %) as opposed to Alg-Anth amide (37 %) in transferring energy to the acceptor. Further hydrophilic–lipophilic balance (HLB) values (>10.0) of both the derivatives indicated their suitability as solubilizers. These water-soluble polysaccharide-based polymers may be of potential utility as photosensitizers for reactions of organic compounds in aqueous media as well as in sensory applications.

ChemInform Abstract: Covalently Anchored n‐Propyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane Chloride on SBA‐15 as a Basic Nanocatalyst for the Synthesis of Pyran Heterocyclic Compounds.

In the present study, highly ordered n-propyl-1,4 diazoniabicycle[2.2.2]octane chloride functionalized mesoporous SBA-15, SBA-DABCO, with high surface area and narrow pore-size distribution was synthesized and characterized by TEM, SEM, FT-IR, CHN, TGA, XRD and BET. The organic-modified SBA-15 has hexagonal crystallographic order, pore diameter up to 54.2 A, and the content of DABCO groups up to 1.38 mmol g−1. The catalyst shows an environmentally benign character, which can be easily prepared, stored and recovered without obvious significant loss of activity. The synthesized basic organocatalyst provides a green and useful method for the one-pot synthesis of pyran annulated heterocyclic compounds, and especially spirooxindole pyran compounds in aqueous media. The significant features of the present protocol are simple, environmentally benign, high yields, no chromatographic separation and recyclability of the catalyst.

Development of stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles and its analytical application to the determination of hydrophobic organic compounds in aqueous media

A novel microextraction technique combining the principles of stir bar sorptive extraction (SBSE) and dispersive micro-solid phase extraction (DμSPE) is presented. The main feature of the method is the use of a neodymium-core stirring bar physically coated with a hydrophobic magnetic nanosorbent. Depending on stirring speed, the magnetic sorbent either acts as a coating material to the stir bar, thus affording extraction alike SBSE, or as a dispersed nanosorbent medium for the collection and extraction of the target analytes, in close analogy to DμSPE. Once the stirring process is finished, the strong magnetic field of the stir bar prevails again and rapidly retrieves the dispersed MNPs. Alike SBSE, the stir bar is collected and the analytes are back-extracted by liquid desorption into an appropriate organic solvent, which is used for analysis. This enrichment technique is easy to prepare since it does not require special surface modification procedures, uses low volumes of non-toxic organic solvents and most importantly imbues SBSE with additional functionalities against a wide range of analytes (since nanosorbents with various coatings can be employed) while it affords additional merits to DμSPE in terms of extraction and post-extraction treatment. As proof-of-concept this new approach was applied to the determination of organic UV filters in seawater samples using oleic acid-coated cobalt ferrite (CoFe2O4@oleic acid) magnetic nanoparticles as sorbent material. The method showed good analytical features in terms of linearity, enrichment factors (11–148), limits of detection (low ngmL−1), intra- and inter-day repeatability (RSD<11%) and relative recoveries (87–120%).

Ferrocenyl derivative of 1,8-naphthalimide as a new turn-on fluorescent sensor for Au(III) ion

Two new compounds containing a ferrocene unit and a strongly fluorescent naphthalimide moiety were designed and successfully synthesized. The incorporation of a hydrophilic triethylene glycol unit can enhance the water-solubility and facilitate the dispersion of compounds in aqueous media. The presence of the ferrocene unit in both compounds results in molecules with low quantum efficiencies due to the photo-induced electron transfer (PET) from naphthalimide to ferrocene. However, one of these compounds exhibits a selective fluorescent turn-on by the addition of Au(III) ion with low to negligible interference by 100-fold concentration of other metal ions in acetonitrile/water. Under optimum conditions, the detection limit for Au(III) ion was 95 ppb.

Bismuth chloride mediated allylation of carbonyl compounds in aqueous media: a mechanistic investigation

The bismuth chloride mediated, aluminum promoted aqueous Barbier type coupling of allyl unit with carbonyl compounds which gives the corresponding homoallyl alcohol is studied. The transient in situ generated allylbismuth(III) bromide intermediate was studied by 1H NMR and GCMS for mechanistic study of allylation. The role of solvent, temperature, and additives in their formation is also studied. The results show that the most reactive intermediate species is CH2CHCH2BiBr2 which mediates allylation of aldehydes and ketones with different substituents with good yields.

Organocatalyzed Green Synthesis of 2,3-dihydropyrazines en Route to Medicinally Privileged Novel Polyheterocyclic Systems

A straightforward green synthesis of 2,3-dihydropyrazines was accomplished under the catalytic influence of (±)-Camphor-10-sulfonic acid at room temperature by condensation of aliphatic 1,2-diamines with α,β-dicarbonyl compounds in aqueous medium. Remarkable aspects of this newly reported method are high yields, use of non-toxic solvents, mild conditions, simple workup and synthesis of complex molecules using an ecofriendly inexpensive organocatalyst. The present method is atom-economical, environmentally benign, and affords synthetically useful and challenging products very rapidly.

Synthesis and Catalytic Activity of Water-Soluble Ruthenium(II) Complexes Bearing a Naphthyridine–Carboxylate Ligand

The synthesis of water-soluble (η6-arene)ruthenium(II) complexes based on pyrazolyl–naphthyridine ligands modified with a carboxylate group is reported. The complexes are easily accessible in good yields via complexation of [(arene)RuCl2]2 with 7-pyrazolyl-1,8-naphthyridine-2-carboxylic acid (1). All complexes have been characterized by spectroscopic and elemental analyses. The complexes {[Ru(η6-arene)(N,N′-1)Cl]Cl} (arene = benzene (5), p-cymene (6)) were further confirmed by X-ray diffraction studies. These complexes are soluble in water (ca. 10 mg/mL) and are catalytically active in hydrogen-transfer reduction of carbonyl compounds in aqueous medium with the use of HCOOH/HCOONa as the hydrogen source.

One-pot synthesis of CdS@Nb2O5 core–shell nanostructures with enhanced photocatalytic activity

CdS@NbxOy core–shell nanostructures were used as heterogeneous catalysts for oxidizing organic compounds in aqueous media under ultraviolet light. The core/shell nanocrystals contained two nanostructured semiconductor that enhanced the catalytic properties of the material under UV–Vis irradiation. The developed core/shell nanocrystals displayed significant catalytic activity during the oxidation of organic substrates and may be suitable for degrading organic pollutants in water. The ESI–MS spectrum obtained for methylene blue after exposure to the nanostructured semiconductor nanoparticles revealed a hydroxylation caused by hydroxyl radicals in solution, forming a species at m/z=301.

Covalently anchored n-propyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride on SBA-15 as a basic nanocatalyst for the synthesis of pyran heterocyclic compounds

In the present study, highly ordered n-propyl-1,4 diazoniabicycle[2.2.2]octane chloride functionalized mesoporous SBA-15, SBA-DABCO, with high surface area and narrow pore-size distribution was synthesized and characterized by TEM, SEM, FT-IR, CHN, TGA, XRD and BET. The organic-modified SBA-15 has hexagonal crystallographic order, pore diameter up to 54.2 A, and the content of DABCO groups up to 1.38 mmol g−1. The catalyst shows an environmentally benign character, which can be easily prepared, stored and recovered without obvious significant loss of activity. The synthesized basic organocatalyst provides a green and useful method for the one-pot synthesis of pyran annulated heterocyclic compounds, and especially spirooxindole pyran compounds in aqueous media. The significant features of the present protocol are simple, environmentally benign, high yields, no chromatographic separation and recyclability of the catalyst.

Immobilization of 1,4-Diazabicyclo[2.2.2]Octane (DABCO) over Mesoporous Silica SBA-15: An Efficient Approach for the Synthesis of Functionalized Spirochromenes

Immobilized 1,4-diazabicyclo[2.2.2]octane (DABCO) over mesoporous silica SBA-15 has been found to be an efficient heterogeneous base catalyst for the synthesis of biologically active functionalized spirochromene derivatives via three-component reaction of isatins/acenaphthoquinone, activated methylene reagents, and 1,3-dicarbonyl compounds in aqueous media. This ecofriendly protocol offers several advantages such as a cost-effective procedure with excellent yield, short reaction time, simple workup, recovery and reusability of catalyst, good functional group tolerance, and broad scope of usable substrates. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]

Highly efficient and selective aerobic oxidation of alcohols in aqueous media by TEMPO-containing catalytic systems

The use of molecular oxygen as the oxidant and water as reaction medium is a charming research orientation in the oxidation of alcohols. In this communication, the efficient aerobic oxidation of alcohols to the corresponding carbonyl compounds in aqueous media has been achieved with TEMPO-containing catalytic systems. In the absence of base/acid, a 99% conversion and 94% selectivity for benzaldehyde were obtained for the oxidation of benzyl alcohol by TEMPO–Ce(IV)–NaNO2 in water. Moreover, the effects of quaternary ammonium salts and anionic surfactants were investigated. The aerobic selective oxidation of different non-heterocyclic alcohols in aqueous media was further investigated, and the moderate to high yields (45.5–98.0%) of products were obtained.

Quantum-chemical modeling of the effect of microhydration and media on the vibrational spectra of 2-(2′-pyridyl)-benzimidazole and its 1-methylsubstituted analogue

Quantum-chemical calculations of the optimized structures, harmonic force fields, and frequencies of 1 : 1 and 1 : 2 complexes of 2-(2′-pyridyl)-benzimidazole and 1-methyl-2-pyridine-2-yl-1H-benzimidazole are performed by means of DFT (B3LYP/6-31+G**). The shifts in the frequencies of the vibrational spectra of the investigated complexes are considered with allowance for the conformational structure and effect of the medium. Analytical bands (spectral marks) are proposed that can be used to identify complexes of 2-(2′-pyridyl)-benzimidazole and 1-methyl-2-pyridine-2-yl-1H-benzimidazole with water. It is concluded that considering the environment within a model of a polarized continuum allows the forecasting of possible shifts in the frequencies in the vibrational spectra of the studied compounds in aqueous media and DMF.

Synthesis of pyran derivatives under ultrasound irradiation using Ni nanoparticles as reusable catalysts in aqueous medium

Abstract Ni nanoparticles (NPs)-catalysed synthesis of pyran derivatives was achieved by one-pot three-component reactions of aryl aldehydes/ketone, malononitrile and C–H activated compounds in aqueous medium under ultrasound irradiation. The present approach offer several advantages, such as shorter reaction time, higher yields, and environmental friendliness.

Efficiency of natural clay as heterogeneous Fenton and photo-Fenton catalyst for phenol and tyrosol degradation

Advanced oxidation processes (AOPs) are particularly useful for cleaning toxic or non-biodegradable materials in wastewater. Among these processes, the advantage of the Fenton processes is the potentially complete mineralization of organic substances. In this work, a naturally containing Fe-clay naturally red clay (NRC) was used as heterogeneous catalyst for the Fenton and photo-Fenton oxidation of two organic pollutants (phenol and tyrosol). NRC was characterized by several complementary methods including chemical analysis, X-ray diffraction, temperature programmed reduction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The influence of different parameters like calcination’s temperature and initial H2O2 concentration were examined considering both the pollutant conversion and the total organic carbon (TOC) abatement. This catalyst was very efficient for the mineralization of both compounds in aqueous medium under mild experimental conditions. Indeed, 100% pollutant conversion could be achieved for both pollutants with a TOC abatement of 90 and 85%, respectively, for phenol and tyrosol by photo-Fenton oxidation. Catalytic activity of NRC was mainly attributed to the amount of iron oxide species (12 wt.%) present naturally in the clay.

Potassium sodium tartrate as a versatile and efficient catalyst for the one-pot synthesis of pyran annulated heterocyclic compounds in aqueous media

Potassium sodium tartrate (KNaC4H4O6·4H2O) was applied as an efficient catalyst for the one-pot, three-component condensation reactions consisting of aromatic aldehydes, malononitrile, and 4-hydroxycoumarin/dimedone/α-naphthol/thiobarbituric acid in aqueous ethanol. Use of nontoxic reaction components, short reaction times, environmental, easy work-up, and high yields are some important advantages of this method.