Classical chemical sciences
The objectives of the reviews are the collection, concise description, comparison and evaluation of the various chromatographic technologies except liquid chromatography using natural and modified cyclodextrins for the increase the seperation capacity of various chromatographic separation systems.
Keywords: cyclodextrins, gas chromatography/mass spectrometry, supercritical fluid chromatography, micellar electrokinetic chromatography, capillary electrokinetic chromatography, countercurrent chromatography
Acetylacetone was coupled with diazotized aryl amines to give arylazoacetylacetones; these when refluxed with 5-amino-3,4- diphenylthieno[2,3-c]pyridazine-6-carbohydrazide in glacial acetic acid yielded the corresponding 5-amino-6-[[4-arylazo-3,5- dimethylpyrazol-1-yl]-carbonyl]-3,4-diphenylthieno[2,3-c]pyridazine dyes. The dyes were applied to polyester fabric, and their spectral and fastness properties measured.
Keywords: arylazopyrazolthieno[2,3-c]pyridazines, 5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carbohydrazide, colour fastness, dispersion dyes
TiCl4–DABCO-mediated reaction of 1-monoaroylated 2,7-dimethoxynaphthalene compound and aromatic amine afforded triarylsubstituted imine compounds with/without cleavage of a methoxy group on the starting naphthalene compound. Three aromatic rings of methyl ether-cleaved imine molecule in crystal are accumulated perpendicularly to each other in crystal.
Keywords: Triarylimine, TiCl4–DABCO mediator, Non-coplanarly organized aromatic-rings accumulating molecules
Polyaniline picrate (PANIPI) was synthesized via facile chemical polymerisation route. The as synthesized PANIPI was characterized using UV-Visible, FT-IR and PXRD spectroscopic techniques. Adsorption capacity of the as prepared resin was evaluated from the sorption process. Sorption isotherms were constructed using Langmuir, Freundlich, Redlich-Peterson and Temkin models. The spectral changes after the sorption process were studied using UV-Visible and FT-IR techniques. Facile pH for the adsorption is found to be 5-7. A comparison of ion exchange capacities of PANIPI revealed selectivity of 3:2
Keywords: polyaniline picrate, sorption isotherms, Ion Exchange Capacity, antimicrobial studies
The corrosion inhibition efficiency of Isonicotinamide (ISN) in controlling the corrosion of carbon steel in 1 M hydrochloric acid solution (HCl) in absence and presence of Z n 2+ has been studied by weight loss method. Weight Loss study reveals that the formulation consisting of 10 ppm of ISN and 10 ppm of Zn2+ has 78% inhibition efficiency. The results of polarisation study shows that the formulation function controls the anodic reaction predominantly. The AC impedance spectra reveal that a protective film formed on the metal surface. FTIR spectrum reveal that the protective film consists of Fe2+-ISN complex on the anodic sites of metal surface and Zn(OH)2 formed on cathodic sites of metal surface.
Keywords: Corrosion, carbon steel, Isonicotinamide, synergistic effect
Coumarins are an important class of organic compounds having biological activities. In the present work coumarin derivatives have been synthesized under solvent free conditions from substituted phenols and ethyl acetoacetate in the presence of catalysts. A catalyst based on clay and heteropoly acid has been synthesized and found to be a potential catalyst for synthesis of coumarin derivatives.
Keywords: coumarin, solvent free condition; heteropoly acids, bentonite
Potassium carbonate catalyzed synthesis of 3-substituted-3-hydroxyindolin-2-ones (A-E) by treating substituted indole-2,3-diones with substituted aryl ketones in aqueous medium under sonication with an object to develop potent antioxidant, antibacterial and antifungal agents of synthetic origin. It is revealed from the antioxidant screening results that the Compound A (3-hydroxy-3-[2-oxo-2-(4-chlorophenyl) ethyl]indolin-2-one) and Compound E (5-Methyl-3-hydroxy-3-[2-oxo-2-(4-fluoro-phenyl)ethyl]indolin-2-one) manifested profound DPPH•, ABTS•+ and NO radical scavenging activity. Compound C elicited the potent inhibitory action against all the bacterial pathogens. Compound A (3-hydroxy-3-[2-oxo-2-(4-chloro-phenyl)ethyl]indolin-2-one) and Compound C (5-Methyl-3-hydroxy-3-[2-oxo- 2-(4-chloro-phenyl)ethyl]indolin-2-one) have showed equivalent activity comparable to standard drug Ampicillin against Pseudomonas aurigonosa. The advantages of this green method utilizing potassium carbonate as an inexpensive, safe, and efficient basic catalyst are high efficiency, mild reaction conditions, convenient operation and environmentally benign conditions.
Keywords: substituted indole-2,3-diones, substituted aryl ketones, aqueous medium, antioxidant, antibacterial and antifungal activity
From the commercial extract of the roots of Glycyrrhia glabra, a triterpene glycoside was isolated which was characterized as 18β- glycyrrhetinic acid-3-O-β-D-glucuronopyranosyl-(1→2)-β-D-glucuronide; also known as Glycyrrhizic acid or Glycyrrhizin. The complete 1H and 13C NMR assignments of Glycyrrhizin were achieved by the extensive 1D (1H and 13C), and 2D NMR (COSY, HMQC, and HMBC) as well as mass spectral data. Further, hydrolysis studies were performed on Glycyrrhizin to identify aglycone and sugar residues in its structure. Further, configuration of sugar moieties in the triterpene glycoside obtained during the course of acid hydrolysis studies were confirmed by preparing their corresponding thiocarbamoyl-thiazolidine carboxylate derivatives with L-cysteine methyl ester and O-tolyl isothiocyanate and in comparison of their retention times with standard sugars.
Keywords: Glycyrrhiza glabra, Fabaceae, triterpene glycoside, 1D and 2D NMR spectral data, structure characterization, hydrolysis, sugar conformation
Materials and environmental chemistry
Polystyrene based strontium phosphate membranes (SPM) prepared by applying different pressures. The membrane potential was measured with uni-univalent electrolytes (KCl, NaCl, and LiCl) solutions using saturated calomel electrode (SCEs). The effective fixed charge density of these membranes was determined by TMS method and it showed dependence of membrane potential on the porosity, charge on the membrane matrix, charge and size of permeating ions. The membranes were characterized by X-ray diffraction, scanning electron microscopy, and IR spectroscopy. The order of surface charge density for electrolytes is found to be KCl > NaCl > LiCl. Other important parameters such as transport number, distribution coefficient, charge effectiveness and related parameters were calculated. The membrane was found to be mechanically stable, and can be operated over a wide pH range. Moreover, the experimental results were found to be quite satisfactorily with theoretical values.
Keywords: Polystyrene-based strontium phosphate membrane; membrane potential; charge density
The nutrient dynamics of the Inner Gulf of Thailand were studied using a simple steady-state budget model, according to the Land–Ocean Interaction in the Coastal Zone modelling guidelines. Two sampling campaigns were carried out during the wet (October 2011) and the dry (February 2012) seasons. For each season, budgets for water and salinity, dissolved inorganic phosphate (DIP) and nitrogen (DIN) were determined. The study indicates that the Inner Gulf exports water at the rate of 133-562 MCM.day-1 in the form of residual flux (VR) at the inner-outer Gulf interface. This results in supply of salt to the inner-outer Gulf interface at the rate of 4.3x103–17x103 ton.d-1. Exchange between the Inner Gulf water and the adjoining seawater replaces this salt loss. Mass balance calculations indicate that the Inner Gulf is a net source for DIP and DIN to the adjacent outer Gulf water at the rate of 4.0x104-3.4x106 molP.d-1 and 4.1x106- 20.5x106 molN.d-1, during the dry and wet season respectively. The high DIP and DIN exports during the wet season probably reflect the inputs coming from the agricultural, domestic and industrial wastes during the severe flooding over Thailand in 2011. Stoichiometric analysis yields the values of net ecosystem metabolisms (NEM; p-r) and net nitrogen production (nfix-denit) in the Inner Gulf at the rate of 4.4x103 tons C.d-1 and 0.7x103 tons N.d-1, indicating that the Inner Gulf is an autotrophic (sink of nutrients) and net nitrogen fixing (nfixdenit >0) ecosystem during the wet season. However in the dry season, the Inner Gulf remains to be autotrophic (p-r = 47 tonsC.d-1) but shifted to be a net denitrifying ecosystem (nfix-denit = -88 tonsN.d-1). Results from the nitrogen and phosphorus biogeochemical cycling revealed the importance of river discharges in the transport and transformation of these substances within the Inner Gulf of Thailand.
Keywords: nutrient budgets, biogeochemical budgets, net ecosystem metabolism, Inner Gulf of Thailand
The levels and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in surface sediments of Koh Sichang anchorage area of Thailand using gas chromatography with flame-ionization detection (GC/FID). The total concentrations of 16 PAHs US EPA priority pollutants varied from 65.2 to 18,970 ng g-1 dw, with a median concentration of 282±3,660 ng g-1 dw. The sediment samples were classified as moderately contaminated compared to those observed in other regions. PAH compositional signatures of surface sediments of the study area were dominated by higher molecular weight PAHs (4-6 rings) comprising about 87 per cent of total PAHs concentrations. Dibenzo[a,h]anthracene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[a]pyrene, fluoranthene, indeno[1,2,3- cd]pyrene, and pyrene represented the highest fractions in most surface sediment samples. Source apportionment using diagnostic PAH ratios indicated that composition of PAHs in most sediment samples originated mainly from incomplete combustion of organic matter (pyrolytic origin), with a mixture of pyrolytic and petrogenic PAHs were observed in some of the study sites. The presence of almost all human carcinogenic PAHs in the study area indicated that these sediments can be considered contaminated sites, suggesting that future monitoring programs together with an effective coastal management program must be implemented to ensure health and safety for all.
Keywords: polycyclic aromatic hydrocarbons (PAHs); source apportionment; diagnostic isomer ratios; Thailand
The photogalvanic behavior of Xylidine ponceau dye was studied in Xylidine ponceau – Tween 60 – ascorbic acid system. The experimental studies were performed at different pH conditions and dye concentrations. The effects of electrode area, light intensity and diffusion length on cell electrical parameter are studied in various experimental conditions. Cell generates maximum power of 68.77 μW in ideal conditions. conversion efficiency was calculated by observed photopotential and photocurrent values at power point.
Keywords: xylidine ponceau, conversion efficiency, storage performance, Tween 60, fill factor, photogalvanic cell, ascorbic acid
Water/n-propanol/nonionic surfactant /phenylacetylene micellar systems were formulated and used for the hydration of phenylacetylene. The ratio (w/w) of n-propanol/surfactant equals 2/1. The surfactants were sucrose laurate (L1695) and Marlipal 24/70 (M2470). The extent of the micellar region as function of temperature was determined. The particle hydrodynamic diameters of the oil-in-water micellar systems measured using dynamic light scattering and were found to decrease with temperature for sucrose laureate and to increase for Marlipal 24/70 based systems. In the diluted region microemulsion systems were observed. Highly efficient hydration of phenylacetylene was performed in these microemulsions. The reaction results indicate that hydration of phenylacetylene is more efficient when sucrose laurate was used for the formulation of the microemulsions.
Keywords: nonionic surfactants, phase behaviour, hydrodynamic diameter, emulsification of substrate, hydration of alkynes
Pyrolysis of virgin and discarded polystyrene, polyethylene, and polyethyleneterephthalate was done by the means of thermo-gravimetric technique. Activation energy was measured by fitting the experimental data to the nth order model. Results have shown that discarded polymers had less activation energy values than those of the virgin polymers. Consequently, energy required for the pyrolysis of discarded polymers must be much less than what is required for virgin polymers. The nth order model has been modified by introducing a new factor which is called degradation index, di. The degradation index, di, accounts for the degradation history of the material. di ranges from 0 to 1 and when it approaches 0 it implies that degradation is anticipated to be severe. When di approaches 1 it implies that polymeric material is virgin. The approach given by current research, i.e. accounting for actual activation energy for discarded polymers, may be crucial for saving energy when recycling plastics materials by pyrolysis.
Keywords: pyrolysis, polystyrene (PS), high density polyethylene (HDPE), polyethyleneterephthalate (PET), activation energy, degradation
Present investigation reveals that Ni-modified Khekordzula clinoptilolyte is characterized by high adsorption capacity against hydrogen sulfide, and HNaX- modified Khekordzula clinoptilolyte has high adsorption capacity against potassium and ammonium ions. Therefore, present zeolites may be used for selective adsorption of hydrogen sulfide, potassium and ammonium ions.
Keywords: adsorption; zeolites; natural waters; wastewaters; Ni-clinoptilolyte; hydrogen sulphide; ammonium ion; potassium ion
The decolorization kinetics of Alizarin Red S (ARS) in aqueous solution was studied using Fenton like reaction in dark environment. The effects of dye, iron(III) ions and hydrogen peroxide concentrations were investigated. The reaction was first order in ARS, H2O2 and zero order in iron(III) chloride. Increasing the hydrogen peroxide concentration (2-8 x10-3 mol dm-3) increases the rate constant from 1.05x10-3 to 3.2 x 10-3 s-1 and excess of hydrogen peroxide shows no effect on the rate constant. Iron(III) ions concentration shows soft retardation effect on the degradation rate of ARS. Increasing the initial ARS concentration from 1 to 4x 10-4 mol dm-3 decreases the decolorization from 85 % to 55 % within 15 minutes. Increasing temperature in the range of 298-313 K increases the rate of degradation and no optimal value detected. In addition, the influence of inorganic additives such, carbonate, nitrate and chloride on the efficiency of dye removal were examined.
Keywords: Alizarin Red S; decolorization; kinetics; Fenton-like
Biochemistry, molecular biology and biotechnology
Berries are widely used nowadays in prevention and in adjuvant therapy of different diseases because of their valuable bioactive agents, antioxidant, anti-tumor and anti-inflammatory properties. It has been observed that berries are used very frequently but without medical control. The main aim of our study was to determine the element content and antioxidant activities in some Latvian varieties of berries (e.g. blueberry, Vaccinium corymbossum L., bilberry, Vaccinium myrtillus L. and red berry, Vaccinium vitis-idaea L.). Element content was measured by ICP-OES. Total antioxidant activity was determined by chemiluminometry and hydrogen-donating ability was measured by spectrophotometry. The berries under examination contain elements in relatively low concentrations and the consumption of these kind of berries is also poor, although they might be good sources for some essential elements; such as blueberry for Mo, bilberry for Li, Mn, Mo and red berry for Cr, Li, Mn, Mo. On the other hand, they have good antioxidant properties, especially bilberry. Beneficial antioxidant capacities and moderate metal ion concentrations support that berries can complete a diverse diet, and they may be a good supplement in some metal-accumulating disorders.
Keywords: mineral elements, free radical scavenging capacity, hydrogen-donating ability, berries
Industrial and engineering chemistry
Keywords: Corrosion inhibitors, EIS, mild steel, organic inhibitors, 1-(8-hydroxyquinolin-2-ylmethyl)urea, SEM, EDAX and biocidal activities
The process of cleaning of hydrocarbon gases by the concentrates of manganese natural ores (Chiatura deposit, Georgia) from sulfur compounds has been investigated. It was shown that critical sulfur content of the adsorbent mass in temperature range of 350-400 0C comprises 15-17 wt. %. The technology of preparation of pelletized oxide-manganese catalyst-adsorbent is proposed. The effect of the parameters of pelletizing process: compacting pressure, composition, type and properties of stabilizing components on formation of secondary structure was established. The data of activity and some physical-chemical characteristics of pelletized oxide-manganese catalystadsorbent are presented.
Keywords: catalyst-adsorbent, manganese oxides, sulfur compounds
Higher tertiary aliphatic amines are widely used in various industries, however, these are not manufactured in China. A substantial amount of C4 fraction is available from the growing petroleum industry which provides the opportunity for the integration of refining with the petrochemicals plant. C4 olefins can be used as starting materials for aliphatic amine production via butene oligomerization. In this paper, the industrial scale synthetic methods for production of tertiary aliphatic amines including the amination of olefins are reviewed.
Keywords: tertiary aliphatic amines, synthesis methods, review