Gas-phase Photocatalytic Oxidation of Acrylonitrile on Sulphated TiO<Subscript>2</Subscript>: Continuous Flow and Transient Study

Abstract  

The gaseous products of photocatalytic oxidation (PCO) of acrylonitrile on sulphated P25 in concentrations from 10 to 100 ppm at 60 to 130 °C were CO₂, HCN and HNCO. This photocatalyst showed disproportionally improved performance at higher temperature and longer retention times. The temperature-programmed oxidation (TPO) after PCO disclosed possible reaction routes.     

Hyperbranched poly (amine-ester)-poly(ε-caprolactone) copolymer and their nanoparticles as camptothecin delivery system

A new amphiphilic hyperbranched poly (amine-ester)-poly(ε-caprolactone) copolymer (HPAE-co-PCL) was synthesized by ring-opening polymerization of ε-caprolactone and branched poly (amine-ester) (HPAE-OHs) with Sn(Oct)₂ as catalyst. The chemical structures of copolymers were determined by FT-IR, ¹H-NMR (¹³C-NMR), thermo gravimetric analysis apparatus (TGA) and differential scanning calorimetry (DSC). Camptothecin (CPT)-loaded copolymer nanoparticles were prepared by the oil-in water (o/w) emulsion technique method. Their physicochemical characteristics, e.g. morphology and nanoparticles size distribution were then evaluated by means of fluorescence spectroscopy, environmental scanning electron microscopy (ESEM), and dynamic light scattering (DLS). CPT-loaded nanoparticles assumed a spherical shape and have unimodal size distribution. It was found that the chemical composition of the nanoparticles was a key factor in controlling nanoparticles size, drug-loading content, and drug release behavior. As the molar ratio of ε-caprolactone to HPAE increased, the nanoparticles size and drug-loading content increased, and the drug release rate decreased. The antitumor activity of the CPT-loaded HPAE-co-PCL nanoparticles against human hepatoma HEPG2 cells was evaluated by 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The CPT-loaded HPAE-co-PCL nanoparticles showed comparable anticancer efficacy with the free drug.     

Resolution of a Five-Component Mixture of Quaternary Ammonium Surfactants on Silica Gel 60 <Emphasis Type=Italic>F</Emphasis><Subscript>254</Subscript> High Performance Thin Layer Chromatographic Plates

The mutual separation of a mixture of cetyltrimethyl ammonium chloride (CTAC), methyl trioctyl ammonium bromide (MTOB), dodecyltrimethyl ammonium chloride (DTAC), benzyltrimethyl ammonium chloride (BTAC) and tetrabutyl ammonium bromide (TBAB), was achieved on silica high performance thin layer chromatographic plates using dimethyl sulfoxide with aqueous sodium-l-tartrate dibasic dihydrate as the solvent system. The effect of concentration of sodium-l-tartrate dibasic dihydrate on the mobility of all the five quaternaries was examined. The limit of detection of CTAC, MTOB, DTAC, BTAC and TBAB was estimated as 0.6, 0.6, 0.3, 0.6 and 0.3 μg/zone, respectively. The method developed was utilized to identify these surfactants in different spiked water samples after their preliminary separation.     

Performance and Microstructural Study on Soap Using Different Fatty Acids and Cations

The desired benefits of the finished soap product are governed by a professional selection of appropriate raw materials, the manufacturing process or both. A better understanding of the crystallization of the soap microstructure is needed which has direct effects on the properties of final products. Soap microstructures and soap composition are not only determined by the length of hydrophobic fatty chain, saturation extent of fatty acid chain, fatty acid distribution but also by the cation effect. Thus, four different fatty acid compositions and the effect of sodium and potassium cations were studied. The performance of the potassium and sodium bar soaps prepared was monitored and was correlated with solid phase thermal analysis. The microstructural effect was examined using ATR-FTIR, FESEM and XRD. The specific ion effect and ion interaction involving both cations and carboxylate anions on different chemical compositions was correlated.     

Nonlinear analysis and reliability of metallic truss structures

The present study goes into the search for the safety domain of civil engineering structures. The objective is to show how a reliability-evaluation brought by a mechanical sizing can be obtained. For that purpose, it is necessary to have a mechanical model and a reliability model representing correctly the behavior of this type of structure.It is a question on one hand, to propose a formulation for the nonlinear calculation (mechanical nonlinearity) of the spatial structures in trusses, and on the other hand, to propose or to adapt a formulation and a modeling of the reliability. The principle of Hasofer-Lind can be applied, in first approach, for the reliability index estimation, scenarios and the probability of failure.The made check concerned metallic in truss structures. Finally, some structures are calculated using the method adapted by Hasofer-Lind to validate the probability approach of the reliability analysis.     

Effects of Reaction Parameters in Catalysis of Glycerol Oxidation by Citrate-Stabilized Gold Nanoparticles

Abstract  

This work describes a catalytic oxidation of glycerol using citrate-stabilized gold nanoparticles (citrate-AuNPs) having a mean diameter of 22 ± 3 nm. A careful product analysis was performed by mean of high-performance liquid chromatography, liquid chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy. Effects of reaction temperature, oxygen pressure, catalyst and reactant concentration, and NaOH/glycerol molar ratio on glycerol conversion, and product yields were investigated. The glycerol conversion and glyceric acid yield were optimum when the oxidation was performed using 0.6 M glycerol and NaOH at 80 °C under 3 bar of O₂ pressure in the presence of 50 ppm citrate-AuNPs catalyst for 3 h.     

The utilization of microencapsulated phase change material wallboards for energy saving

Wallboards with micro encapsulated phase changing material (micro PCM) were used to investigate the performance and the energy saving characteristics as building materials in winter and summer climate conditions. The test house consisted of a boiler with under floor heating system, an air conditioner, micro PCM wallboard room and conventional wallboard room. The outer temperature of the rooms could be artificially controlled at the temperature range of −12 to 35 °C. Micro PCM content in wallboards was 0–4 kg/m². The melting temperature and latent heat of Micro PCM are 23 °C and 211 J/g. Also, micro PCM shows stable mechanical strength under 500 psi. As micro PCM content increased, the temperature fluctuations decreased. In case of micro PCM wallboard, temperature profiles in the room show stable and comfortable ranges. The optimum amount of micro PCM in wallboard to maximize energy saving efficiency was around 3 kg/m².     

Methylation of methyltrichlorosilane with methyl chloride over active metals and activated carbon

Gas phase methylation of methyltrichlorosilane with methyl chloride to high-valued dimethyldichlorosilane was carried out by using metallic aluminum as a chlorine acceptor in the co-presence of activated carbon, tin, and zinc. The addition of activated carbon in metallic aluminum significantly enhanced the methylation of methyltrichlorosilane, and dimethyldichlorosilane was dominantly produced. Activated carbon played a catalyst role in the methylation reaction. When active metals, such as tin and zinc, were added in the mixture of aluminum and activated carbon, the active metals and activated carbon synergistically catalyzed the methylation of methyltrichlorosilane with methyl chloride toward the formation of dimethyldichlorosilane.