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61.
El Sayed H. El Ashry Mahmoud A. M. Nassr Yeldez El Kilany Ahmed Mousaad 《Advanced Synthesis \u0026amp; Catalysis》1986,328(1):1-6
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. 相似文献
62.
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. 相似文献
63.
Omar Mahmoud Georgia Biazus Soares Gil Yosipovitch 《International journal of molecular sciences》2023,24(1)
Transient Receptor Potential (TRP) channels are multifunctional sensory molecules that are abundant in the skin and are involved in the sensory pathways of itch, pain, and inflammation. In this review article, we explore the complex physiology of different TRP channels, their role in modulating itch sensation, and their contributions to the pathophysiology of acute and chronic itch conditions. We also cover small molecule and topical TRP channel agents that are emerging as potential anti-pruritic treatments; some of which have shown great promise, with a few treatments advancing into clinical trials—namely, TRPV1, TRPV3, TRPA1, and TRPM8 targets. Lastly, we touch on possible ethnic differences in TRP channel genetic polymorphisms and how this may affect treatment response to TRP channel targets. Further controlled studies on the safety and efficacy of these emerging treatments is needed before clinical use. 相似文献
64.
Mahasen S. Amine Amal A. Mahmoud Samy K. Badr Alaa S. Gouda 《Journal of surfactants and detergents》2012,15(2):179-190
The titled compounds were prepared from 2-amino-5-heptadecyl[1,3,4]thiadiazole (1). Diazotization of (1) produced (2) which was coupled with active methylene compounds and gave azo ⇌ hydrazono derivatives (3A, 3B)
a–d
. It was found that there is regio-specificity for addition of different nucleophiles to these tautomers; thus, nitrogen nucleophiles
such as hydrazine hydrate, hydroxylamine hydrochloride and thiourea were reacted via Azo tautomer (3A) to yield pyrazole, isoxazole and pyrimidine respectively (5-7), while carbon nucleophiles as phenylisocyanate was reacted via the hydrazono tautomer (3B) and produced triazine derivatives (4). Additionally, the diazonium chloride (2) was coupled with alkaline 2-naphthol and produced 2-(5-heptadecyl-[1,3,4]thiadiazol-2-yl)-1,2-dihydro-3-oxa-1,2-diaza-cyclopenta[a]naphthalene
(8). UV–visible spectra of the synthesized colored compounds (2-8) showed λ max at 374–398 nm, while screening these compounds in vitro against micro-organisms (including structure-activity relationship
SAR study) revealed high antibacterial and moderate antifungal activities. Propoxylation of compounds 1, 3, 5, 6, 7 and 8 with 3, 5, 7 mol of propylene oxide produced nonionic surfactants I(a–c)–IX(a–c) having surface active properties so, it is clear that the tested surfactants can be used in the manufacture of dyes, drugs,
cosmetics, emulsifiers, pesticides, luminphores for optical applications and many other industries with low toxicity to human
beings and the environment owing to their high solubility and good biodegradability. 相似文献
65.
Manar El-Sayed Abdul-Raouf Abdul-Raheim Mahmoud Abdul-Raheim Nermine El-Sayed Maysour Hamed Mohamed 《Journal of surfactants and detergents》2011,14(2):185-193
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 相似文献
66.
Mahmoud Roushani Zeinab Abdi Ali Daneshfar Abdollah Salimi 《Journal of Applied Electrochemistry》2013,43(12):1175-1183
A simple and sensitive electrochemical sensor based on nickel oxide nanoparticles/riboflavin-modified glassy carbon (NiONPs/RF/GC) electrode was constructed and utilized to determine H2O2. By immersing the NiONPs/GC-modified electrode into riboflavin (RF) solution for a short period of time (5–300 s), a thin film of the proposed molecule was immobilized onto the electrode surface. The modified electrode showed stable and a well-defined redox couples at a wide pH range (2–10), with surface-confined characteristics. Experimental results revealed that RF was adsorbed on the surface of NiONPs, and in comparison with usual methods for the immobilization of RF, such as electropolymerization, the electrochemical reversibility and stability of this modified electrode has been improved. The surface coverage and heterogeneous electron transfer rate constants (k s) of RF immobilized on a NiO x –GC electrode were approximately 4.83 × 10?11 mol cm?2, 54 s?1, respectively. The sensor exhibits a powerful electrocatalytic activity for the reduction of H2O2. The detection limit, sensitivity and catalytic rate constant (k cat) of the modified electrode toward H2O2 were 85 nM, 24 nA μM?1 and 7.3 (±0.2) × 103 M?1 s?1, respectively, at linear concentration rang up to 3.0 mM. The reproducibility of the sensor was investigated in 10 μM H2O2 by amperometry, the value obtained being 2.5 % (n = 10). Furthermore, the fabricated H2O2 chemical sensor exhibited an excellent stability, remarkable catalytic activity and reproducibility. 相似文献
67.
Mahmoud A. Zarraa 《化学工程与技术》1998,21(3):301-305
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: Jd = 3.71Re–0.54 and, Jd = 2.5 Re–0.61where Jd is mass transfer J-factor and Re is the Reynolds number. 相似文献
68.
Polyacrylonitrile (PAN) in dimethylformamide solution containing 0.25 or 1 wt% graphene oxide (GO) was gel spun to tapes. Scanning electron microscopy of tapes showed compact staircase cross-sections hallmarking the gel spun products. Low shear rate rheometry of the tape precursors revealed a viscosity increase, while the structural viscosity indexes of dispersions dropped to 40 and 70% at high shear rates by 0.25 and 1 wt% GO inclusion, respectively. Furthermore, the sol–gel transition temperature of PAN solution was enhanced by about 2.5 and 10 °C with 0.25 and 1 wt% GO inclusion, respectively. Strain sweep test implied a gel-to-sol transition from 9 to 28% by 1 wt% GO inclusion. The experimental reinforcement coefficient corresponded the aligned Halpin–Tsai model confirming the suitable dispersion preparation route namely master batch dilution implementing strong interphase formation among the PAN chains and GO platelets. Molecular evolution analysis during air stabilization through a combined second derivative of FTIR spectra, Gaussian peak fitting represented by Isd index, indicated the initial cyclization at 290 °C followed by its enhanced rate. Final Isd was noticed to be 48% higher for the tapes containing GO nanosheets. GO inclusion not only enhanced the tape heat of stabilizations but also differentiated its proportional Isd and toughness dependency based on the heat of stabilization. 相似文献
69.
Synthesis of modified catalyst and stabilization of CuO/NH4‐ZSM‐5 for conversion of methanol to gasoline 下载免费PDF全文
Ehsan Kianfar Mahmoud Salimi Vahid Pirouzfar Behnam Koohestani 《International Journal of Applied Ceramic Technology》2018,15(3):734-741
In this article, the catalytic conversion of methanol to gasoline range hydrocarbons has been studied over CuO/ NH4‐ZSM‐5(3,5,7,9%) catalysts prepared via sono‐chemistry methods. In order to improve, copper oxide can be used as a booster on NH4‐ZSM‐5 this catalyst property. Accordingly, the conversion process of Methanol to Gasoline (MTG) was conducted under a pressure of 1 atm and temperature of 400°C by a fixed‐bed reactor on copper oxide catalysts which were prepared based on synthetic NH4‐ZSM‐5. The synthetic catalyst was investigated by such analyses as BET, XRD, FT‐IR, and SEM. Formation of copper oxide phase and proper distribution of copper oxide were proven on the basic level of using XRD analysis. BET analysis showed the reduction in catalyst level and SEM images depicted the proper distribution of particles. The present investigation is to study the effect of CuO loading on NH4‐ZSM‐5 support for conversion of methanol to gasoline range hydrocarbons. A series of CuO/ NH4‐ZSM‐5 catalysts were prepared, characterized, and experimented for their performance on methanol conversion and hydrocarbon yield. 相似文献
70.