Recovery of gold cyanide using inherently conducting polymers

Removal of gold from basic solutions containing [Au(CN)₂]^? has been demonstrated using the inherently conducting polymer polypyrrole. Polymers containing sulfonated aromatic dopants have been found to display a significant ability to remove gold from such solutions. Experiments performed in solutions containing both gold and copper cyanide complexes indicate that the recovery process is not highly selective. However, the polypyrroles used display significantly faster rates of gold recovery than activated carbon. © 2003 Society of Chemical Industry     

Effects of α‐form or β‐form nuclei on polymorphic crystalline morphology of poly(butylene adipate)

The effects of α‐form and β‐form nuclei on polymorphic morphology of poly(butylene adipate) (PBA) upon recrystallization from the molten state up to various T_max values were examined by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and polarized light microscopy (PLM). In this study, PBA with complex melting and polymorphism behaviour was used as a model for examining different types and extents of residual nuclei. As the PBA initially containing the sole α‐crystal was brought to a molten state of various T_max, the extents of trace α‐form crystal nuclei varied and were dependent on T_max. Furthermore, it did not matter whether, initially, the PBA contained α‐ or β‐form crystals (or both) because only a single type of α‐nuclei could be left upon treatment to the molten liquid state at T_max. Therefore, only the α‐crystal in PBA had ‘memory capacity’ in the molten liquid state while the β‐crystal did not. This was so because the latter had been completely transformed into the solid state prior to being heated into a liquid. PBA crystallized before α‐nuclei could be packed into α‐crystal, regardless of the crystallization temperature (T_c). For recrystallization from molten PBA without any nuclei, the crystalline polymorphism was correspondingly influenced by T_c. Copyright © 2005 Society of Chemical Industry     

Synthesis of (R,S)-10-methyloctadecanoic acid (tuberculostearic acid) and key chiral 2-methyl branched intermediates

Tuberculostearic acid, (R)-10-methyloctadecanoic acid, is a characteristic component of pathogenic mycobacteria and related organisms. Sensitive detection of this acid in infected material allows rapid detection of mycobacterial disease. A novel, convergent synthesis of tuberculostearic acid and key chiral intermediates is described in this communication, to provide a reference compound. Racemic and (R)- and (S)-1-iodo-2-methyldecanes were synthesised from 1-octanal and 1-carboethoxyethylidenetriphenylphosphorane as initial starting materials. 1-Hydroxyoct-7-yne was made from 1,6-hexanediol by two alternative methods and coupled with the above racemic iodide. Hydrogenation and oxidation of the resulting (R,S)-10-methyloctadec-7-yn-1-ol gave racemic tuberculostearic acid.     

Heparin effect on hydrolysis of fibrin clots in a bull and a man with varying fibrinolytic systems

Heparin was studied for its effect on the hydrolysis time of clots from desAA fibrin (FB), desAABB fibrin (F0) and fibrinogen (Fg) of a bull and a man by gly-or lys-plasminogen which is activated by the tissue activator. It is shown that heparin in the concentration to 4.6 M does not affect that hydrolysis time of clots from human and bovine Fg and human Fg by gly-plasminogen which is activated by the tissue activator. Heparin increases the hydrolysis time of clots from bovine Fg and F0 by gly-and lys-plasminogen, the tissue activator being present. It firstly increases (in concentrations below 0.5 (microM), and then decreases (in concentrations above 0.5 (microM) the hydrolysis time of clots from human FB, F0 and Fg and bovine FB and F0 by plasmin. In concentration 4.6 microM heparin increases the hydrolysis time of clots from human fibrinogen by fibrinolytic systems. Effect of heparin on fibrinolytic process from the viewpoint of affine interactions between the components of fibrin clots is discussed.     

The effect of substitution of Mn or Al on the hydrogen sorption characteristics of CeNi5

The hydrides of the ternary alloys of CeNi_5?xM_x (M = Mn or Al and x = 0.5 and 0.75) have been prepared and investigated. The absorption plateau pressure of the system CeNi₅—H is reduced 8- to 75-fold, by the replacement of Ni by Mn (or Al), without significantly impairing its hydrogen capacity. This substitution has great influence in reducing the hysteresis effect associated with the hydrogen absorption and desorption. The hysteresis and plateau-sloping factors are very low compared with that in Mischmetal-Ni₅ hydride. The enthalpies and entropies of hydrogenation and dehydrogenation for CeNi_5?xM_x are computed and found to be in the range 20–25 kJ(mole H₂)^?1) and ～90–100 J(K mole H₂)^?1, respectively. The high effective entropies of the hydride (high configurational entropy of H in the lattice) are attributed to extensive hydrogen disorder in the interstitial sites of the CeNi_5?xM_x lattice. Desorption of the hydrogen in the two-phase region (α + β) for CeNi_4.25Mn_0.75-H follows first-order kinetics with an activation energy of ～33 ± 1 kJ(mole)^?1. The favorable physiochemical properties of CeNi_5?xMn_x-H system make it very attractive for applications.