Synthesis and reactions of 2-(p-chloroanilino)-5- (D-galacto-1,2,3,4,5-pentahydroxypentyl)-1,3,4-thiadiazole

Oxidative cyclization of D -galactose (p-chlorophenyl)thiosemicarbazone gave 2-(p-chloroanilino)-5-( D -galacto-1,2,3,4,5-pentahydroxypentyl)-1,3,4-thiadiazole ( 1 ), whose acetylation afforded 2-[N-acetyl-N-(p-chlorophenyl)]-amino-5-( D -galacto-1,2,3,4,5-pentacetoxypentyl)- 1,3,4-thiadiazole ( 3 ). Its periodate oxidation of the glycol groups gave 2-(p-chloroanilino)-1,3,4-thiadiazole-5-carboxaldehyde ( 4 ), which can be transformed into 1,2-[2-(p-chloroanilino)-1,3,4-thiadiazol-5-yl]-1-hydroxy-2-oxoethane. A number of hydrazones of the formyl thiadiazole was prepared and its reduction with sodium borohydride gave 2-(p-chloroanilino)-5-hydroxymethyl-1,3,4-thiadiazole ( 6 ), whose acetylation gave a mono-O-acetyl derivative ( 7 ). Oxidation of the formyl thiadiazole gave 2-(p-chloroanilino)-1,3,4-thiadiazole ( 9 ). The spectral data of the compounds were discussed.     

Field-Assisted Ion Exchange in Type III Silica

Field-assisted ion exchange of protons in type III silica for Cs or Nu ions from a molten salt was investigated. Although electrolysis occurred, infrared measurements showed no change in hydroxyl content after ion exchange for extended periods. Scanning electron microprobe studies of cesium-exchanged specimens revealed a high-cesium-content layer =2,μm thick; this layer is believed to result from surface reaction with the molten salt.     

Effect of Drag–Reducing Polymers on the Rate of Liquid-Solid Mass Transfer in Fixed Beds of Spheres under Forced Convection Conditions

The effect of drag–reducing polymers on the rate of liquid – solid mass transfer in a packed bed reactor under forced convection conditions was studied by measuring the rate of diffusion–controlled dissolution of copper spheres in acidified chromate solutions. The variables investigated were superficial liquid velocity, sphere diameter, bed height, and polymer concentration. The mass transfer coefficient was found to increase with increasing superficial liquid velocity. Increasing both sphere diameter and bed height were found to decrease the mass transfer coefficient. Polymer addition was found to decrease the rate of mass transfer by an amount ranging from 29.2 to 56.9% depending on superficial liquid velocity and polymer concentration. Mass transfer data were correlated in absence and in the presence of drag–reducing polymer, using the following equations, respectively: J_d = 3.71Re^–0.54 and, J_d = 2.5 Re^–0.61where J_d is mass transfer J-factor and Re is the Reynolds number.     

Synthesis,Surface-Active Properties,and Emulsification Efficiency of Trimeric-Type Nonionic Surfactants Derived From Tris(2-aminoethyl)amine

Trimeric-type nonionic surfactants based on tris(2-aminoethyl)amine were prepared. N-alkyl chloride (namely, octanoyl chloride, n-decanoyl chloride, n-dodecanoyl chloride) was reacted with tris(2-aminoethyl)amine in the presence of toluene and triethylamine. The products were partially reduced and then ethoxylated by poly(ethylene glycol) of molecular weights 400, 1,000, and 2,000 g mol⁻¹. The structures were confirmed by infrared (IR) and ¹HNMR spectroscopy. The molecular weights of the surfactants were measured by gel permeation chromatography (GPC). The properties of the prepared compounds were investigated by the surface tension, interfacial tension, and cloud point. The emulsification power of the prepared surfactants for oil-in-water emulsions was also studied and the emulsion stability was monitored by an optical microscope and the bottle testing method. Some factors affecting the emulsion stability were investigated     

Theoretical Analysis of the Onset of Gas Entrainment from a Stratified Region through a Single Side‐Oriented Branch at Moderate Froude Numbers

A theoretical investigation has been conducted for the prediction of the critical height at the onset of gas entrainment during single discharge from a stratified, two‐phase region, through a branch installed on an inclined flat wall. The predicted critical height at the onset of gas entrainment was proven to be a function of Froude number (Fr) and density ratio of the interface fluids. Three different experimental data sets at wall inclination angles of zero, 45 and 90 degrees (i.e. side, inclined and bottom branches) were used for comparisons. A good concurrence was illustrated between the experimental and theoretical values.     

Designing zinc oxide nanostructures (nanoworms,nanoflowers, nanowalls,and nanorods) by pulsed laser ablation technique for gas-sensing application

In this study, pulsed laser ablation technique, also known as pulsed laser deposition (PLD), is used to design and grow zinc oxide (ZnO) nanostructures (nanoworms, nanowalls, and nanorods) by template/seeding approach for gas-sensing applications. Conventionally, ZnO nanostructures used for gas-sensing have been usually prepared via chemical route, where the 3D/2D nanostructures are chemically synthesized and subsequently plated on an appropriate substrate. However, using pulsed laser ablation technique, the ZnO nanostructures are structurally designed and grown directly on a substrate using a two-step temperature-pressure seeding approach. This approach has been optimized to design various ZnO nanostructures by understanding the effect of substrate temperature in the 300-750°C range under O₂ gas pressure from 10-mTorr to 10 Torr. Using a thin ZnO seed layer as template that is deposited first at substrate temperature of ~300°C at background oxygen pressure of 10 mTorr on Si(100), ZnO nanostructures, such as nanoworms, nanowalls, and nanorods (with secondary flower-like growth) were grown at substrate temperatures and oxygen background pressures of (550°C and 2 Torr), (550°C and 0.5 Torr), and (650°C and 2 Torr), respectively. The morphology and the optical properties of ZnO nanostructures were examined by Scanning Electron Microscope (SEM-EDX), X-ray Diffraction (XRD), and photoluminescence (PL). The PLD-grown ZnO nanostructures are single-crystals and are highly oriented in the c-axis. The vapor-solid (VS) model is proposed to be responsible for the growth of ZnO nanostructures by PLD process. Furthermore, the ZnO nanowall structure is a very promising nanostructure due to its very high surface-to-volume ratio. Although ZnO nanowalls have been grown by other methods for sensor application, to this date, only a very few ZnO nanowalls have been grown by PLD for this purpose. In this regard, ZnO nanowall structures are deposited by PLD on an Al₂O₃ test sensor and assessed for their responses to CO and ethanol gases at 50 ppm, where good responses were observed at 350 and 400°C, respectively. The PLD-grown ZnO nanostructures are very excellent materials for potential applications such as in dye-sensitized solar cells, perovskite solar cells and biological and gas sensors.     

A global optimal formulation for the water integration in eco-industrial parks considering multiple pollutants

A mathematical programming formulation for the water integration in eco-industrial parks considering streams with several pollutants is presented. The formulation is based on a superstructure that allows the wastewater reuse in the same plant, the water exchange with different plants, and a shared set of interceptors that must be selected to determine the network configuration that satisfies process equipments and environmental constraints. The model formulation considers wastewater with several pollutants, and optimizes the network according to the minimum total annual cost, which includes the costs of fresh water, piping and regeneration. A new discretization approach is also proposed to handle the large set of bilinear terms that appear in the model in order to yield a near global optimal solution. The results obtained in several examples show considerable savings with respect to the solutions of the individual plant integration policy commonly employed for these types of problems.     

Surface Properties and Thermodynamic Parameters of Some Sugar-Based Ethoxylated Amine Surfactants: 1—Synthesis,Characterization, and Demulsification Efficiency

Several ethoxylated sugar-based amine surfactants have been synthesized and characterized by IR and ¹HNMR spectroscopy. The surface activity of the prepared compounds has been thoroughly studied and some of their surface properties (such as CMC, Γ_max, and A _min) have been calculated. The surface properties of the prepared compounds were correlated to their chemical structure. It was found that CMC decreases when increasing the molecular weight of polyethylene glycols, whereas A _min increases. Furthermore, the thermodynamic parameters of adsorption and micellization were also calculated. They include ΔG, ΔH, and ΔS of micellization and adsorption. The data show that the synthesized surfactants favor adsorption, so that they can be used as demulsifiers for crude oil emulsions. In this respect, the demulsification test was carried out and the results of demulsification efficiency were correlated to the chemical composition of the investigated compounds. Some factors that affect the demulsification efficiency were also considered.     

Synthesis and Evaluation of a New Cationic Surfactant for Oil-Well Drilling Fluid

A new additive cationic surfactant for drilling fluid was synthesized by alkylation of coal tar phenol with tetradecyl alcohol; then, the alkyl phenol reacts with formaldehyde and amine to produce the Mannich base product. This product was reacted with sodium chloroacetate to produce the cationic surfactant; the structure of the synthesized surfactant was confirmed by FTIR analysis, evaluation of the prepared surfactant by surface properties such as surface tension, emulsification power, and wetting power. The prepared cationic surfactant showed good results when utilized in the formulation of both oil-based mud and synthetic-based mud as the primary emulsifier.     

Direct electron transfer from glucose oxidase immobilized on a nano-porous glassy carbon electrode

A pair of well-defined and reversible redox peaks was observed for the direct electron transfer (DET) reaction of an immobilized glucose oxidase (GOx) on the surface of a nano-porous glassy carbon electrode at the formal potential (E°′) of −0.439 V versus Ag/AgCl/saturated KCl. The electron transfer rate constant (k_s) was calculated to be 5.27 s⁻¹. The dependence of E°′ on pH indicated that the direct electron transfer of the GOx was a two-electron transfer process, coupled with two-proton transfer. The results clearly demonstrate that the nano-porous glassy carbon electrode is a cost-effective and ready-to-use scaffold for the fabrication of a glucose biosensor.