Kinetic and thermodynamic analysis of degradation of doripenem in the solid state

The kinetic and thermodynamic parameters of degradation of doripenem were studied using a high‐performance liquid chromatography method. In dry air, the degradation of doripenem was a first‐order reaction depending on the substrate concentration. At increased relative air humidity, doripenem was degraded according to the autocatalysis kinetic model. The dependence ln k = f1/T) was described by the equations ln k = 5.10 ± 13.06 ? (7576 ± 4939)(1/T) in dry air and ln k = 46.70 ± 22.44 ? (19,959 ± 8031)(1/T) at 76.4% relative humidity (RH). The thermodynamic parameters E_a, ΔH^≠a, and ΔS^≠a of the degradation of doripenem were calculated. The dependence ln k = f (RH%) was described by the equation ln k = (0.155 ± 0.077) × 10^?1 (RH%) ? (3.45 ± 21.8) × 10^?10. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 722–728, 2012     

PEGylated poly(amidoamine) dendrimers-based drug loading vehicles for delivering carboplatin in treatment of various cancerous cells

Journal of Nanoparticle Research - Highly ordered TiO2 nanotube arrays (TiO2 NTs) were synthesized by anodization method using a titanium foil and further modified with nanoparticles...     

The synthesis,characterization and effect of molar mass distribution on solid-state degradation kinetics of oligo(orcinol)

Journal of Thermal Analysis and Calorimetry - In this study, the oxidative polymerization of orcinol monohydrate using different oxidants such as NaOCl, H2O2, and air was investigated....     

Variation of radioactivity and trace metal elements during the growth period of water spinach

Journal of Radioanalytical and Nuclear Chemistry - Plants uptake and accumulate nutrient from the surrounding area in different amounts depending on the nutritional needs of plants in each...     

Immobilization of an Iridium Pincer Complex in a Microporous Polymer for Application in Room-Temperature Gas Phase Catalysis

An iridium dihydride pincer complex [IrH₂(POCOP)] is immobilized in a hydroxy-functionalized microporous polymer network using the concepts of surface organometallic chemistry. The introduction of this novel, truly innocent support with remote OH-groups enables the formation of isolated active metal sites embedded in a chemically robust and highly inert environment. The catalyst maintained high porosity and without prior activation exhibited efficacy in the gas phase hydrogenation of ethene and propene at room temperature and low pressure. The catalyst can be recycled for at least four times.     

Hybrid nanoflowers bearing tetraphenylporphyrin assembled on copper(II) or cobalt(II) inorganic material: A green efficient catalyst for hydrogenation of nitrobenzenes in water

Simple fabrication of organic–inorganic hybrid nanoflowers (TPP@CuhNfs and TPP@CohNfs) was achieved with tetraphenylporphyrin (TPP) as organic counterpart and Cu²⁺ or Co²⁺ ions as inorganic materials via a green route, with lower cost and controlled pH. The effect of pH levels and TPP concentrations on the morphology of the TPP@CuhNfs and TPP@CohNfs materials was examined by scanning electron microscopy (energy-dispersive X-ray [EDX]). The formation and chemical structures of TPP@CuhNfs and TPP@CohNfs were evaluated using Fourier transform infrared. Elemental analyses of these hybrid nanoflowers were carried out by EDX. The fabricated TPP@CuhNfs and TPP@CohNfs nanomaterials under optimum conditions act as effective reusable catalysts for the hydrogenation of nitroanilines in aqueous media at ambient temperature. The time-dependent hydrogenation can be easily monitored spectrophotometrically and verified by ¹H-nuclear magnetic resonance. These types of the catalytic reaction or system are recorded to be useful toward the hydrogenation of nitroanilines, regardless of the position and type of substrate. Moreover, TPP@CuhNfs and TPP@CohNfs catalysts demonstrated a type of metal ions-dependent catalytic efficiency toward hydrogenation of nitroanilines (organic pollutants), with TPP@CuhNfs found to be more effective than TPP@CohNfs. However, both catalysts containing Cu²⁺ and Co²⁺ ions showed good performance and can be reused at least five times without a significant decline in yield. The presented approach based on hybrid nanoflowers provides as a low cost and ecofriendly method (green route) for different catalytic hydrogenations.     

Preparation of hydrogenated natural rubber with nanomatrix structure

Hydrogenated deproteinized natural rubber (HDPNR) with nanomatrix structure was prepared through graft‐copolymerization of acrylonitrile and styrene onto HDPNR particle in latex stage. Structural characterization of the resulting materials through nuclear magnetic resonance and Fourier‐transform infrared spectroscopy confirmed that acrylonitrile and styrene were grafted onto HDPNR. The weather resistance, thermal properties, mechanical properties, storage modulus, and morphology of the resulting materials were investigated in comparison with those of HDPNR. The obtained result indicated that the graft‐copolymerization of HDPNR with hydrogenation conversion of 60 mol% attained the highest grafting efficiency. Thermal resistance and storage modulus of HDPNR‐graft‐poly (styrene‐co‐acrylonitrile) (HDPNR‐g‐SAN) were superior compared with those of HDPNR and deproteinized natural rubber. This was attributed to the nanomatrix formed in HDPNR‐g‐SAN, which was confirmed through a transmission electron microscope. Ribbed smoked sheet natural rubber exhibited the outstanding mechanical properties and weather resistance when it was mixed with HDPNR‐g‐SAN.