Adel A.-H. Abdel-Rahman

Adsorption Properties of Uranium (VI) Ions on Reactive Crosslinked Acrylamidoxime and Acrylic Acid Copolymer Resins

Crosslinked acrylic acid (AA) acrylonitrile (AN) copolymer was prepared by suspension copolymerization in the presence of poly (vinyl alcohol) as suspending agent and N,N-methylenebisacrylamide (MBA) and divinylbenzene (DVB) as crosslinking agents. The molecular ratios between AN and AA was 95: 5 mol%. Different ratios 2, 5, and 10 wt% of crosslinkers was used. The nitrile group of the copolymer was converted to acrylamidoxime in the presence of hydroxylamine. Morphologies of the prepared resins were examined by scanning electron microscope (SEM). Recovery of uranium ions was investigated. The adsorption of uranium was occurred in nitric acid, hydrochloric acid and sulfuric acid solutions. Effect of pH, time of loading, type of acid, ratio, and type of crosslinker were investigated. Regeneration of eluted resins was determined.

Trichloroacetimidate as a Leaving Group in the Ferrier Rearrangement: Highly Stereoselective Synthesis of Pseudogalactal Glycosides

The Ferrier rearrangement of a galactal derivative 2 bearing the trichloroacetimidate functionality as a leaving group at the C-3 position was performed in the presence of trimethylsilyl triflate as catalyst; the corresponding pseudogalactal glycosides were obtained in excellent yield and stereoselectivity with a wide range of acceptors.

Antimicrobial activity of new 4,6-disubstituted pyrimidine, pyrazoline, and pyran derivatives.

A number of new 2,6-didisubstituted pyrimidine, pyrazoline, and pyran derivatives were synthesized starting from their chalcone derivative. The synthesized compounds displayed different degrees of antimicrobial activity against Bscillus subtilis (Gram-positive), Pseudomonas aeruginosa (Gram-negative), and Streptomyces species (Actinomycetes).

Studies on the Uptake of Uranium(VI) Ions on Polyacrylamidoxime Resins Synthesized by Free Radical Polymerization with Different Crosslinking Ratios and Pore Solvents

Uptake of uranyl ions on polyacrylamidoxime resins synthesized from polymerization of acrylonitrile, and divinylbenzene as crosslinking agent in the presence of different diluents, then conversion of polyacrylonitrile to polyacrylamidoxime by hydroxylamine in basic media were investigated. FTIR on base polymer, functional resins, resins loaded with uranyl ions and that after elution were investigated. The effect of pore solvents on the morphologies of the prepared resins were examined by scanning electron microscope. Loading of uranyl ions performed with respect effects of pH, time of loading, and ratio of crosslinker. Elution of adsorbed ions carried out with different eluent and elution efficiency were determined. Regeneration of resins performed after six cycles and regeneration efficiency were determined.

Application of New Modified Poly(ethylene Oxide)-Block-Poly(propylene oxide)-Block-Poly(ethylene oxide) Copolymers as Demulsifier for Petroleum Crude Oil Emulsion

Water soluble nonionic amphiphilic block copolymers based on hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(propylene glycol) (PPG) were prepared. Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymers, PEG-PPG-PEG, were prepared in the normal condition. The chemical composition and molecular weights of the prepared copolymers were determined from 1H NMR and GPC techniques. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for water in crude-oil emulsions that were pronounced at different ratios of crude oil: water at 318 K and 333 K. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 100% based on demulsifier chemical compositions and concentrations.

STEREOSELECTIVE SYNTHESIS OF PSEUDOGLYCAL C-GLYCOSIDES VIA TRICHLOROACETIMIDATE ACTIVATION OF GLYCALSa

A variety of functionalized pseudoglycal C-glycosides (C-pseudoglycals or C-hex-2-enopyranosides) have been obtained in excellent yield and stereoselectivity from the trimethylsilyl triflate (Me 3SiOTf) catalyzed reaction of trichloroacetimidate derivative 2 with silylated nucleophiles such as allyl and propargyl silanes and silyl enol ethers. a Dedicated to Prof. Joachim Thiem on the occasion of his 60th birthday.

Functionalization of Magnetic Chitosan Particles for the Sorption of U(VI), Cu(II) and Zn(II)—Hydrazide Derivative of Glycine-Grafted Chitosan

A new magnetic functionalized derivative of chitosan is synthesized and characterized for the sorption of metal ions (environmental applications and metal valorization). The chemical modification of the glycine derivative of chitosan consists of: activation of the magnetic support with epichlorohydrin, followed by reaction with either glycine to produce the reference material (i.e., Gly sorbent) or glycine ester hydrochloride, followed by hydrazinolysis to synthesize the hydrazide functionalized sorbent (i.e., HGly sorbent). The materials are characterized by titration, elemental analysis, FTIR analysis (Fourrier-transform infrared spectrometry), TGA analysis (thermogravimetric analysis) and with SEM-EDX (scanning electron microscopy coupled to energy dispersive X-ray analysis). The sorption performances for U(VI), Cu(II), and Zn(II) are tested in batch systems. The sorption performances are compared for Gly and HGly taking into account the effect of pH, the uptake kinetics (fitted by the pseudo-second order rate equation), and the sorption isotherms (described by the Langmuir and the Sips equations). The sorption capacities of the modified sorbent reach up to 1.14 mmol U g−1, 1.69 mmol Cu g−1, and 0.85 mmol Zn g−1. In multi-metal solutions of equimolar concentration, the chemical modification changes the preferences for given metal ions. Metal ions are desorbed using 0.2 M HCl solutions and the sorbents are re-used for five cycles of sorption/desorption without significant loss in performances.

Anti-HIV Activity of New Substituted 1,3,4-Oxadiazole Derivatives and their Acyclic Nucleoside Analogues

A number of new 5-[(naphthalen-5-yloxy)methyl]-1,3,4-oxadiazole derivatives, 2 - 5 and 8 - 11, were synthesized. The 2-{5-[(naphthalen-5-yloxy)methyl]-1,3,4-oxadiazol-2-ylthio}acetohydrazones 6a and 6b were synthesized by the reaction of the hydrazide 4 with the corresponding monosaccharides. Cyclization of the sugar hydrazones 6a and 6b with acetic anhydride afforded the substituted oxadiazoline derivatives 7a and 7b. The synthesized compounds were evaluated for their antiviral activity against, the human immunodefi ciency virus (HIV-1) and some of these compounds showed moderate to high antiviral activity.

Synthesis and Anti-HBV Activity of Thiouracils Linked via S and N-1 to the 5-Position of Methyl β-D-Ribofuranoside

Abstract Reverse nucleoside derivatives of 2-(methylsulfanyl)uracils 6a-d were prepared by treating of the sodium salt of 2-(methylsulfanyl)uracils (5a-d) with methyl 2,3-O-isopropylidene-5-O-p-toluenesulfonyl-β-D-ribofuranoside (2). The alkylation of 2-thiouracils 4a-d with methyl 5-deoxy-5-iodo-2,3-O-isopropylidene-D-ribofuranoside (3) afforded the corresponding S-ribofuranoside derivatives 8a-d. Deisopropylidenation of 6a-d and 8a-d afforded the corresponding deprotected derivatives 7a-d and 9a-d, respectively. The Anti-HBV activity of selected compounds was studied.

Adsorption of Uranium (VI) Ions on Hydrazinyl Amine and 1,3,4-Thiadiazol-2(3 H)-thion Chelating Resins

Nitrogenous compounds are the most widely used in solid phase extraction due to its low cost, easy convertible to many functional groups. These have large adsorptive capacity toward heavy metal ions as rare earth elements (REEs) and uranium with ability for recovering from low concentrate solutions. Synthesis of resins were carried out by polymerization of acrylonitrile with divinyl benzene as crosslinker. Treatment of the resulted precipitate with hydrazine hydrate in ethanol produce hydrazinyl methyl amine which has high chelating capacity toward uranyl ions. 1,3,4-Thiadiazol-2(3H)-thion derivative was yielded by reaction of hydrazinyl amine with carbon disulfide in methanol. This reaction carried out in the presence of methyl benzoate and dioctyl phthalate as pore producing solvent which used to improve physical properties and adsorptive character of the resins. Optimization on the two resins during loading and elution were carried out using solution with different concentrations. The optimum factors during adsorption and elution were recognized.