Volume 69, Issue 12

There is currently a significant increase in the use of glycerol as a renewable solvent for catalytic reactions. Glycerol has often been the solvent of choice in both homogeneous and heterogeneous catalyses, despite its high viscosity at ambient temperature and the low solubility of highly hydrophobic reagents found in glycerol. Its biodegradability and non-toxicity have led to reports of improved reaction performance and selectivity, as well as easier product separation and effective catalyst recycling. All relevant advances in this emerging field of “green” catalysis are thoroughly reviewed below.

Ethyl glucuronide (EtG) is a metabolite and a specific marker of alcohol consumption that can be detected days after the complete elimination of alcohol after drinking. A rapid, simple, and sensitive LC-ESI-MS/MS method for the determination of urinary ethyl glucuronide was developed and fully validated in accordance with analytical standards, using the C 18 column. The whole process including sample preparation and LC-MS/MS lasted 10 min. A comprehensive validation including HorRat, measurement uncertainty, system suitability and intermediate precision calculations among analysts, and a cut-off limit study was performed. The method was applied to real samples and a cutoff limit determination study. The LOD and LOQ (using the IUPAC and Eurachem methods) were determined as 104.21 ng mL −1 and 165.00 ng mL −1 . A cut-off limit of ≈ 818 ng mg −1 (normalised to creatinine) was found for urinary EtG. The results showed that the cut-off limits currently in use should be re-considered in further studies and standardised on a global scale. Normalisation to creatinine is important because of the risk of the dilution of urine intentionally or with a change of diet. The concentrations of real samples from subjects who had consumed alcohol were successfully predicted using this method, after zero HS-GC/MS results of urine alcohol concentration.

Two validated chromatographic methods developed for the analysis of S clopidogrel bisulphate in the presence of its related substances listed in the United States and British Pharmacopoeias including its inactive R enantiomer are described. The first method is a simple thin layer chromatographic (TLC) method where separation is performed on pre-coated silica gel 60 F254 plates using methanol/diethylamine/heptanes/water containing 20 mg vancomycin hydrochloride (7 : 7 : 1.5 : 0.5 vol. %) as a mobile phase. R f values were found to be 0.69, 0.74, 0.78, 0.84 and 0.88 for R clopidogrel, S clopidogrel, related substances A, B1 and B2, respectively. The second method depends on the separation by HPLC on a Lux polysaccharide chiral column with UV detection at 220 nm using 0.1 vol. % diethyl amine in methanol pumped at a rate of 1 mL min −1 . Retention times were found to be 1.90 min, 2.82 min, 3.00 min, 3.27 min and 3.71 min for the related substances A, B1, C which are clopidogrel R enantiomer, B2, and S clopidogrel, respectively. The proposed methods were validated in accordance with the ICH guidelines and successfully applied to the determination of S clopidogrel bisulphate in pure powder and dosage forms without interference from the excipients and to affirm the dosage form to be pure S clopidogrel and devoid of the R enantiomer, which is inactive.

Palygorskite (PG)-supported manganese oxide catalysts (MnOx/PG) were prepared for the selective catalytic reduction (SCR) of NO with ammonia in the presence of SO 2 at low temperature. The influence of gaseous SO 2 on the performance of the catalyst was studied by means of specific surface area (Brunauer-Emmett-Teller, BET) analysis, scanning electron microscopy (SEM), thermogravimetric (TG) analysis, temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). The results showed that the SCR activity of Mn10/PG was significantly inhibited by gaseous SO 2 at temperatures below 300°C. However, the SCR activity of Mn10/PG was markedly promoted by SO 2 in a higher temperature range of 300°C to 500°C. The sulphating of surface active species (MnOx) was suggested to inhibit the oxidation of NH 3 to NO leading to enhancement of the SCR activity at a higher temperature range of 300°C to 500°C and decrease in the SCR activity at temperatures below 300°C.

Core-shell composite beads comprising a Pd-loaded Al 2 O 3 core and a shell of inter-grown silicalite-1 (siliceous ZSM-5) crystals were synthesised. The incompatibility between the Pd/Al 2 O 3 core and the zeolite shell was circumvented by a layer-by-layer self-assembly of polyelectrolyte to adsorb nanosized silicalite-1 seeds onto the core surface, followed by a secondary solvo-thermal treatment to form the continuous and well-intergrown silicalite-1 shell. The thickness of the outer zeolite shell could be tuned by monitoring the secondary growth time. When employed as catalyst for the hydrogenation reaction of alkenes to explore its full potential use, the Pd/Al 2 O 3 @silicalite-1 core-shell catalyst exhibited excellent size-selectivity, poison-resistance and leaching-proof properties. Such a catalyst@zeolite core-shell structure is expected to find promising applications in heterogeneous catalysis and adsorption.

The subject of this paper was to study the effect of rapid batch decompression on hydrolysate quality and on biogas yield after the hydrothermal pretreatment of wheat straw. An aqueous batch containing 5 mass % total solids of wheat straw was thermally and thermally-expansionary treated in parallel at the process temperature of 170-200°C and the residence time of 0-60 min. An analysis of the thermal and thermal-expansionary hydrolysate provided identical results in the dependences and values of chemical oxygen demand, acidities, and glucose yields of both treatments based on severity factors including the combined effects of temperature and residence time. Increases in the methane content of 33 % for thermally and of 34 % for thermally-expansionary treated wheat straw were reached in comparison to the methane yield from an untreated sample. This means that the polysaccharide cell wall was dissolved because of the high process temperature and residence time. From this it follows that all its nutrients were subsequently washed out of the cell into liquid where they caused changes in its chemical oxygen demand, glucose content, and acidities. There was therefore no rapid decompression effect on the hydrothermally treated wheat straw.

The phenolic composition of Fetească neagră and Băbească neagră grapes from Dealul Bujorului vineyard (south-east Romania) was studied using the spectrophotometric and high-performance liquid chromatographic (HPLC) methods. The results revealed significant differences between these cultivars. Total anthocyanins ranged from 0.22-5.98 mg g −1 DW berries in Băbească neagră grapes to 0.54-18.54 mg g -1 DW berries in Fetească neagră. Both cultivars were characterised by an interesting anthocyanin profile for winemaking with a prevalence of malvidin-3-glucoside. The skins and seeds both had small amounts of flavonoids. In contrast with Băbească neagră, Fetească neagră had more flavonoids in the seeds (69 %) than in the skins. Statistically significant correlations were observed between antioxidant activity and total anthocyanin content in both varieties. The antioxidant activity was also found to be highly correlated to the total phenolic compounds content.

Some plants collected (Mentha aquatica, Bidens tripartita and Ambrosia artemisiifolia) from an unusual habitat developed in recent years in Bucharest (the so-called “Bucharest Delta”) and the contents of polyphenolic compounds, short-chain organic acids and heavy metals, and radical scavenger activity, were determined. 12 polyphenolic compounds and 7 short-chain organic acids were quantified using high-performance liquid chromatography and capillary electrophoresis; Mentha aq. extracts presented the highest levels of rosmarinic acid (1.58 mg g −1 ) and ferulic acid (2.84 mg g −1 ) and Bidens extracts presented the highest concentrations of chlorogenic acid (0.44 mg g −1 ); the same extracts contain the most important levels of luteolin (0.52 mg g −1 ) or other flavonoids. All the heavy metals detected in the plants studied were found in very low levels (the highest was Pb(II) in Mentha aquatica, (12.84 ± 0.48) μg kg −1 ). The study sought to identify the active compounds and some contaminants in plants collected from the “Bucharest Delta” with the intention of eventual exploitation of the habitat and to enhance the knowledge of such human-modified ecosystems.

The reaction of anhydrous zinc chloride with 2,3-thiophenedicarbaldehyde bis(semicarbazone) or 2,3-bis(thiosemicarbazone) leads to the formation of compound {[C 6 H 5 N 2 S] + [ZnCl 3 (C 6 H 4 N 2 S)] − }, where C6H4N2S is thieno[2,3-d]pyridazine, via an elimination-cyclisation reaction of the semicarbazone or the thiosemicarbazone moiety. Crystal structures of thieno[2,3-d]pyridazine and {[C 6 H 5 N 2 S] + [ZnCl 3 (C 6 H 4 N 2 S)] − } are described. 2015 Institute of Chemistry, Slovak Academy of Sciences

A novel polymerizable hydrophobic monomer 1-(4-dodecyloxy-phenyl)-propenone (DPP) was synthesized by esterification, Frise rearrangement and Williamson etherification; then, the obtained DPP was copolymerized with 2-(acrylamido)-dodecanesulfonic acid (AMC 12 S) and acrylamide (AM) initiated by a redox initiation system in an aqueous medium to enhance oil recovery (EOR). AM/AMC 12 S/DPP (PADP) was characterized by FT-IR, 1 H NMR spectroscopy, environmental scanning electron microscopy (ESEM), DSC-TG, fluorescent probe, core flood test, etc. Results of ESEM and fluorescent probe indicate that hydrophobic microdomains and associating threedimensional networks were formed in the aqueous solution of PADP. Results of DSC-TG demonstrated that long carbon chains, aromatic groups and sulfonic groups were incorporated into the PADP polymer, which can lead to a significant increase of the rigidity of molecular chains. Performance evaluation of experiments showed superior properties in regard to temperature-tolerance, shear-tolerance and salt-tolerance. In the Sandpack Flooding Test, PADP brine solution showed a significant increase in EOR at 65◦C because of its high thickening capability. All these features indicate that PADP has a potential application in EOR at harsh conditions.

A benzophenone-containing SET-LRP initiator based on renewable and abundant cardanol was synthesised in 71 % yield using the selective etherification reaction. Next, methyl methacrylate (MMA) as a monomer was polymerised under SET-LRP conditions using the newly prepared initiator to prepare cardanol-end poly(methyl methacrylate) (PMMA). The kinetic results of the polymerisation indicated that the reaction was controllable when the monomer conversion was lower than approximately 50 %, and the molecular masses of PMMA measured by GPC were higher than the theoretical values while the monomer conversion was more than 50 %. In addition, most of the carbon-carbon double bonds of the side hydrocarbon chain of the end-cardanol group in the PMMA were kept intact from 1 H NMR spectrum characterisation. Accordingly, when the cardanolend PMMA together with a tertiary amine-containing cardanol derivative was irradiated by UV light, the corresponding UV-cured resin was obtained. The chemical resistance and hardness of the UV-cured film were enhanced with the increasing irradiation time.

In the present work, linear polystyrene (PS) was functionalized by a sulfonation reaction providing sulfonated polystyrene (PSS). Then, the PSS polymer chains were cross-linked with the 1,4- phenylene diisocyanate (PPDI) group in tetrahydrofuran (THF), which led to a PSS-PPDI polymer. The PSS-PPDI was grafted by diethylenetriamine (DETA) in a solution of THF to obtain polymer PSS-PPDI-DETA. Their structures were characterized by infrared spectroscopy (ATR-FTIR), elemental analysis (EA), differential scanning calorimetry (DSC), thermogravemetric (TGA), thermodynamic (DTA) and differential thermogravimetric (DTG) analysis. Subsequently, the obtained polymers were tested for their ability to remove some metal ions from aqueous media such as Zn 2+ , Cd 2+ and Co 2+ .

The ligand N 2 ,N 6 -bis(2-hydroxyethyl)pyridine-2,6-dicarboxamide (L or BHPC) was synthesised by modification of 2,6-pyridinedicarboxylic acid then used to construct the lanthanide-based mesoporous material Tb-BHPC-SBA-15. In the structure of the resulting Tb-BHPC-SBA-15, lanthanide ions were chelated by the BHPC ligand and the Tb-BHPC complexes were anchored into the SBA-15 host formed by the reaction between the hydroxyl group and the active Si-OH. The mesoporous material Tb-BHPC-SBA-15 was characterised by UV, small-angle X-ray diffraction (SAXRD) patterns, nitrogen adsorption/desorption isotherms and fluorescence spectra. The results indicate that the ligand and lanthanide ions were introduced into the SBA-15 host and the mesoporous material Tb-BHPC-SBA-15 exhibited the characteristic luminescence of Tb 3+ .

Modern glycan analysis is primarily based on mass spectrometry, where instruments based on electrospray or matrix-assisted laser desorption ionization are currently the most frequently used. In the present study, electrospray ionization (ESI) coupled with a high-resolution Fourier transform mass spectrometer (LTQ Orbitrap) and matrix-assisted laser desorption/ionization (MALDI) coupled with a time-of-flight (TOF/TOF) detector were used to analyze two N-glycan standards with intact free reducing ends (disialo biantennary and asialo triantennary) and representative PA-labeled human serum N-glycan structures isolated by hydrophilic interaction anion-exchange chromatography (HIAX), confirmed by 1 H NMR analysis and consequently compared with the ProteinScape Glycome database. Different combinations of ion sources with fragmentation devices results in various fragmentation patterns and adducts. Also, the effect of sample derivatization on the acquired signals is discussed. Compared to the MALDI technique, free glycans did not lose labile sialic acids easily in the ESI source. On the other hand, fluorescent PA-labeling leads to improved core fragmentation and signal intensities; linkage-specific ethyl esterification leads to reduced adduct and fragment formation and enhanced stability of sialic acids in the MALDI ion source. Thereby, both methods have their advantages and disadvantages in terms of detection, fragmentation and robustness.