GC/MS analysis of gaseous degradation products formed during extrusion blow molding process of PE films

Results of the investigation of volatile organic compounds emission during polyethylene extrusion are presented. Two polymers of different processing properties were tested, namely linear low density polyethylene (ExxonMobil) and high density polyethylene (Liten FB 29). Blowing film extrusion in experimental technological line using a single screw extruder as the imported element was done. VOCs were collected on sorbent tubes containing Tenax. Gas chromatography coupled with mass spectrometry (GC/MS) was applied for the identification of volatile degradation products. PE LLD material emits a significantly larger amount of hydrocarbons than PE-HD. Its emission contains mainly C18 and C20 hydrocarbons (alkanes, 1-alkenes, and α,ω-alkadienes). In case of the PE-HD polymer, lower degradation was observed and C18 and C23 hydrocarbons were emitted.     

The phase envelopes of alternative solvents (ionic liquid,CO2) and building blocks of biomass origin (lactic acid,propionic acid)

Solid–liquid, liquid–liquid and vapour–liquid equilibrium measurements for binary and ternary systems containing building blocks of biomass origin such as propionic acid, lactic acid and alternative solvents like carbon dioxide and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid have been carried out at 313.15 K. The binary solid–liquid and liquid–liquid equilibrium measurements were performed at ambient pressure. The vapour–liquid equilibrium was studied in the range of pressure from 3.54 to 12 MPa while ternary systems were examined at 9, 10 and 12 MPa. The samples from the coexisting phases were taken and the compositions of both liquid and vapour phases were determined experimentally. The three-phase system was observed for lactic acid + ionic liquid + CO₂ as well. The achieved results were correlated using the Peng–Robinson equation of state with the Mathias–Klotz–Prausnitz mixing rule. The set of interaction parameters for the employed equations of state and the mixing rule for the investigated systems were obtained.     

Isothermal vapour–liquid equilibria in the binary and ternary systems consisting of an ionic liquid, 1-propanol and CO2

Vapour–liquid equilibrium measurements for binary and ternary systems containing carbon dioxide, 1-propanol, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids are presented in this work. The binary CO₂ + 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide system at 313.15 K at pressure range from 2 to 14.4 MPa was examined. The obtained phase envelop shows that even at low pressure of CO₂ the solubility of the gas in the ionic liquid is high. The ternary phase equilibria were studied at 313.15 K and pressures in the range from 9 to 12 MPa. The ternary phase diagrams show that higher CO₂ pressure diminishes the miscibility gap.     

Thermal analysis of nanostructured calcite crystals covered with fatty acids

The way of precipitation process conducting is crucial for the final product properties and its further applications. In present experiments, the CaCO₃ powders, produced by controlled fast precipitation trough gaseous CO₂ absorption in Ca(OH)₂ slurry, have been covered by two fatty acids: dodecanoic (lauric) acid and tetradecanoic (myristic) acid. This multiphase reaction was conducted in a new rotating disc reactor unit which enables to control inter- and intra-face mass and energy transfer as well as the macro- and micromixing effects in the reacting system. The obtained nanopowders have been observed by the use of the scanning electron microscope. The X-ray diffraction technique as well as the dynamic light scattering (DLS) and the thermogravimetric method (TG) were further used for its deep analyses. The experimental data have allowed for distinction between different fatty acid molecules species present on calcite surface (chemisorbed ones, inter-located between adsorbed to surface, formed mono- and bilayers and the soap) or free fatty acids molecules if presented in the sample. The amount of fatty acid species forming different layers on calcite as well as the size and distribution of fatty acid coated CaCO₃ powders have been also calculated.     

Synthesis,crystal structure and other properties of the complexes of Er(III), Yb(III) and Lu(III) with 4,4′-bipyridine and dichloroacetates

A novel mixed-ligand complexes of Er(III), Yb(III) and Lu(III) with title ligands were prepared and characterized by chemical and elemental analysis and IR spectroscopy, conductivity (in methanol, dimethyloformamide and dimethylsulphoxide). The thermal properties of complexes in the solid state were studied. The mode of metal–ligand coordination was discussed. The title compounds are isomorphic and isostructural in solid state. All atoms in studied compounds lie in general positions but occurrence of inversion on the midpoint of the bond linking two pyridine rings leads to existence in asymmetric unit one complex molecule and half of outer coordination sphere 4-bpy molecule. All chelating carboxylate groups are symmetrically bonded to the metal cations. The molecules of studied compounds are connected to the three dimensional network via O–H···O and O–H···N intermolecular hydrogen bonds. In the structures also exist C–H···O, C–H···Cl weak hydrogen bonds and π····π stacking interactions.     

ESI-MS detection of very weak <Emphasis Type="Italic">π</Emphasis>-Stacking interactions in the mixed-ligand sandwich complexes formed by substituted benzo-crown ethers and metal cations

The stability of the mixed-ligand complex formed by amino-benzo-15-crown-5 and nitro-benzo-15-crown-5, with a metal cation, [NH₂B15C5+NO₂B15C5+K]⁺, was found to be enhanced by π-stacking interactions. This conclusion was deduced by comparison of the abundance of the mixed-ligand complex with the abundances of homo-ligand complexes ([(NH₂B15C5)₂+K]⁺, [(NO₂B15C5)₂+K]⁺), as well as with those of 1:1 complexes ([NH₂B15C5+K]⁺, [NO₂B15C5+K]⁺). Some solvents and some metal cations with large radii were also found to prevent the existence of π-stacking interactions.     

On-column derivatization with o-phthaldialdehyde for fast determination of homocysteine in human urine

A new assay for urinary homocysteine is described. The assay relies on an on-column derivatization with o-phthaldialdehyde, using a reversed-phase HPLC column and detection/quantification by fluorescence. The analysis time for reduced and total homocysteine, including sample work-up, was 5 and 13 min, respectively. Quantification limit was 25 nM.     

Linear information for approximation of the Itô integrals

We study optimal approximation of stochastic integrals in the Itô sense when linear information, consisting of certain integrals of trajectories of Brownian motion, is available. Upper bounds on the nth minimal error, where n is the fixed cardinality of information, are obtained by the Wagner–Platen algorithm and are O(n ^???3/2) or O(n ^???2), depending on considered class of integrands. We also show that Ω(n ^???2) is a lower bound which holds even for very smooth integrands.     

Synthesis of the first pseudo-phosphonopeptides derived from (ferrocenyl)aminomethanephosphonous acids

The first example of the condensation of (ferrocene)-N-benzhydrylamino-methanephosphonous acid (1) with α-amino acids 2a-d and several model dipeptides 4a-d and the tripeptide dl-alanyl-dl-leucinyl-glycine (4e) in the presence of DCC resulted in pseudo-phosphono-dipeptides 3a-d and pseudo-phosphono-oligopeptides 5a-d. The probable chiral assistance of the incoming amino acid or peptide in the formation of the new chiral center on phosphorus was also a feature of this method.     

A method of convergence acceleration of some continued fractions

A new method of convergence acceleration is proposed for continued fractions , where and are polynomials in (, ) for sufficiently large. It uses the fact that the modified approximant approaches the continued fraction value, if is sufficiently close to the th tail . Presented method is of iterative character; in each step, by means of an approximation , it produces a new better approximation of the th tail . Formula for is very simple and contains only arithmetical operations. Hence described algorithm is fully rational.