Zeitschrift für chemische Wissenschaften

The aim of the present study was to investigate the phytochemistry and bioactive nature of Tridax procumbens. The ethanol, benzene and petroleum ether extracts of dried roots of this plant were investigated for phytochemistry and antibacterial analysis. The antibacterial activity was evaluated against different bacterial strains viz. Escherichia coli, Staphylococcus aureus, Salmonella typhii, Klebsiella pneumoniae and Shigella flaxineri by detecting zone of inhibition. The zone of inhibition was compared with standard discs of Gentamicin. From these extracts, two of them (ethanolic and pet-ether extracts) revealed significant results as compared to benzene extract. The qualitative analysis revealed the presence of flavonoids, pholabatannins, resins, tannins, phenols, lipids and fats and carbohydrates.

Bio-diesel has become more attractive as an alternative fuel for diesel engine because of its environmental benefits and the fact that it is made from renewable resources such as vegetable oil and animal fats by reacting them with short chain alcohols. The present research work focus on optimization of water degummed Linseed biodiesel from transesterification process which involves the exchanging of organic group R” of an ester with the organic group of alcohol R’ often catalysed by the addition of an acid or base catalyst. It was found that the maximum recovery of biodiesel yield was depicted at the optimum operation conditions (0.8% catalyst amount NaOH, reaction time 1 hour and reaction temperature 60°C). The comparison with the fuel properties of conventional diesel, especially with regards to kinematic viscosity and carbon residue, oil needs to purify through the degumming process to remove the gums before use in biodiesel production. The effect of degumming on fuel properties of water degummed Linseed methyl ester and their different diesel blends are discussed in this paper.

The commercial cation exchangers TSKgel BioAssist S, TSKgel CM-2SW and TSKgel CM-STAT have been used for the separation of 111In (III) from Cd (II) and Cu (II) ions. The separation was carried out using low cost cation exchangers based on the differences in the sorption affinity of In, Cu and Cd towards the ion exchanger from 0.01 mol L-1 HCl. The effects of various parameters such as shaking time, HCl concentration and acetate buffer concentration were examined. A comparative study between cation exchangers showed the best one for radiochemical separation yielded more than 98% within 50 min by using column study.

Although chalcones symbolize an important pharmacophore for variety of biological actions, however their analogues are also reported to be equally important for plethora of biological actions. In the present review, a comprehensive study of chalcones derived molecules (like pyrazoles, isoxazoles, pyridine, pyrimidine) their pharmacological actions, mechanism of action, structure activity relationship studies have been described.

Protic Ionic Liquids (PILs), a substantial branch of the infamous Ionic Liquids (ILs) have gained much attention in recent years. They have been the “go-to” solvent of choice in many areas such as chromatography, catalysis, fuel cells, biological applications etc., due to their thermophysical properties and their ability to be tunable based on task specificity. This review covers two parts, namely; a brief description on the thermophysical properties of acetate PILs (density, speed of sound, viscosity and decomposition temperature) and its current applications in the industry. The collation of the physicochemical data consents structure-property trends would be discussed, and these can be used as a foundation for the development of new PILs to achieve specific properties. Economically, PILs have been suggested as “greener” alternatives to conventional solvents in various industrial applications hence, in order to assess their suitability for such purposes, a thorough evaluation of their mutagenicity, toxicity and carcinogenicity is crucial.

An overview of applications of density functional theory (KS/DZVP-GGA, demon2k, or B3LYP/6-311G(d,p), Gaussian 09) to a wide range of problems in theoretical organic chemistry with examples is given, namely thermodynamic properties, geometries (bullvalene), charges (glycine cation), dipole moments, electrostatic potential (acetyl chloride and acetamide), spectroscopy (IR/Raman: acetaldehyde, UV/Vis: polyenes, NMR: thujone and EPR: Koelsch’s radical), gas phase acidities and pKa values (substituted benzoic acids), supramolecular chemistry (quinhydrone complex), and reaction pathways.

A new comparative series of barbituric acid and thiobarbituric acid based chalcone derivatives bearing the pyrimidine nucleus were synthesized. The chemical structures of the resulting molecules were characterised by means of FT-IR (Fourier Transform Infrared) 1H NMR, 13C-NMR (Nuclear Magnetic Resonance) and HMBC (Heteronuclear Multiple-Bond Correlation) and Elemental Analysis. All synthesized compounds were subjected to in vitro antimicrobial screening against four bacterial strains i.e., one Gram Positive (Bacillus subtilis MTCC 441), two Gram Negative (E. coli MTCC 443, P. aeruginosa MTCC 1688), and one Fungal (C. albicans MTCC 227) Strains. The structure activity relationship is discussed on the basis of bioactivity results, various functional groups present and position of the functional group at various positions of the synthesized compounds. The comparative antimicrobial activity study of both of the series elucidated that shows the chalcone compounds containing -thioketo group are more potent than the -keto group.

γ-Irradiated polyvinyl alcohol (PVA)/Citric acid blend hydrogels were prepared. Effect of radiation dose on gel fraction and swelling properties were observed. Effect of pH and NaCl concentration on swelling ratio, water absorption and water desorption of γ-irradiated hydrogels were studied. It was found that gel fraction attains maximum up to a certain dose but swelling ratio as well as water absorption decreases with increase in radiation doses. Swelling properties decreases with the increase in concentration of NaCl solution too and increases with the increase of pH.

The catalytic performances of bifunctional vanadium oxide supported on Hβ zeolite with redox and acid properties were investigated for dimethyl ether (DME) direct oxidation to polyoxymethylene dimethyl ethers (DMMx) (x=1-2). The best catalytic performance was obtained over 15%V2O5/Hβ. The catalysts were characterized by XRD, BET, NH3-TPD, H2-TPR, XPS and FT-IR in order to provide the further insight in the relationship of structure and activity. When the loading content of vanadium oxide was 15%, the presence of oxide species was dominantly the polymeric vanadia. The addition of vanadium oxide to the H-beta zeolite not only provided redox sites, but also changed the acid strength and distribution of H-beta zeolite as confirmed by NH3-TPD measurement, and the positive correlation was found between the DMMx selectivity and the ratio of weak and strong acid sites. The introduction of vanadium oxide with appropriate amount to the H-beta zeolite promoted the balance between the acid sites and redox sites, which was very vital for obtaining high DMMx selectivity.

The overall aim of this study is to gain a better understanding of the historic use of woad in Sweden in the 18th and 19th centuries. A key question is, whether it is possible to distinguish between indigo from woad and exotic indigo using Raman spectroscopy? Reference samples prepared according to historic recipes using woad, exotic indigo, logwood and brazilwood - were used to dye different textile fibres - cotton, wool and linen. In addition, various reference compounds - indigotin, indirubin, kaempferol, luteolin, 3-hydroxyflavone and tryptanthrin - as well as the ‘flower’ of the woad dye bath were analysed to identify specific fingerprint regions for each compound. Blue threads from four historic textiles - a skirt and three rag balls - from the region of Hälsingland were then analysed in comparison to the references. A specific peak at 993 cm-1 was identified in the spectra taken from the flower of the woad vat, which we suggest possibly arises from 3-hydroxyflavone. DSA-ToF-MS analysis suggests flavoneglycosides as possible candidates. However, cellulosic substrates show a broad vibration at 999 cm-1 overlapping the flavone signature, thus rendering it non-diagnostic, but it might be possible to use this peak in Raman analyses supported by mass spectrometry to distinguish between indigo from woad and exotic indigo if the substrate is wool or if it is a pigment. Raman analyses of the historic samples identify the colourants as indigo and possibly woad and logwod mixed with brazilwood.