2024-03-28T19:17:50Z
https://ejchem.journals.ekb.eg/?_action=export&rf=summon&issue=288
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Effect of Sm3+ Ions on the Transport and Sublattice Magnetization of Perovskite System
PEROVSKITE compounds (La1-xSmx)0.7 Ca0.3MnO3 0 ≤ x ≤ 0.14
…. were prepared using the double sintering ceramic technique. The measurement of the magnetic susceptibility at different temperatures as a function of the magnetic field intensity showed the change of the state from completely ordered to completely disordered state at T
C which shifts to lower value by increasing Sm content. The tolerance factor decreases with increasing Sm concentration. Resistivity measurements indicate the disappearance of the related peaks with increasing Sm content. The large increase in the resistivity below 530K is related to the spin transition of Mn3+ ions from high to low state.
Transport phenomena
Magnetic properties
AC resistivity and Perovskite
2010
03
02
1
15
https://ejchem.journals.ekb.eg/article_1201_62f0a8460a7dbc6e35d33764157072f4.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Focus on the Synthesis and Reactions of Some New Pyridine Carbonitrile Derivatives as Antimicrobial and Antioxidant Agents
3-(4-CHLOROPHENYL)-1-(2,4-dichlorophenyl)-propen-1-one (1) was prepared and reacted with active methylene compound, ethyl cyanoacetate in the presence of ammonium acetate to give the corresponding pyridine carbonitrile (2). The behavior of compound 2 towards phosphorous pentasulfide, phosphorous oxychloride and some acyclic-sugars has been investigated and afforded compounds 3, 4 and 5a-d, respectively. The thioxo-pyridine carbonitrile (3) reacted with different halo compounds namely: methyl iodide, ethyl chloroacetate, some acyclic sugars to afford 6, 7 and 8a-c, respectively. Treatment of compound 3 with acrylonitrile afforded compound 9. Reaction of the thiosulfanyl 6 with hydrazine hydrate gave the hydrazino derivative 10 while reaction of 7 with the same reagents gave the acid hydrazide 11. Also, compound 4 reacted with different nucleophiles to afford compounds 10, 12-14. Condensation of compound 10 with ethyl acetoacetate, acetyl acetone, acetic anhydride, p-chlorobenzaldehyde afforded compounds 15-18, respectively. Moreover, compound 10 reacted with carbon disulfide to afford compound 19. Finally, condensation of compound 10 with aldehydo-sugar namely: D-glucose gave the corresponding acyclic nucleoside 20. Furthermore, biological evaluation of some prepared compounds has been assessed and some of them revealed promising antimicrobial and antioxidant activity.
Pyridines
Nicotinonitrile
Pyrazolopyridine
Triazolopyr-idine
Acyclic nucleosides
Antimicrobial activity and Antioxidant agent
2010
03
02
17
35
https://ejchem.journals.ekb.eg/article_1202_74d9b0544ffba71ca39126249b9a2805.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Effects of Ferric and Chromic Salts in Physicochemical, Surface and Catalytic Properties of Pure and Doped Fe2O3-Cr2O3 System
FERRIC/CHROMIC mixed oxides having the formula 0.85 Fe 2O3: 0.15 0.15CCr2O3 were obtained by thermal decomposition of the mixed hydroxides prepared from mixed nitrate and sulphate solutions using NH4OH. Pure mixed hydroxides were heated at 500°C .The doped solids were prepared by treating the precipitated hydroxides with different amounts of Li2O and K2O (0.5, 0.75 and 1.5 mol %) followed by calcination at 500°C. The techniques employed were XRD, N2-adsorption and oxidation of CO by O2 at 200-300°C. The results revealed that pure and doped systems consisted of nanocrystalline phases having crystallite size varying between 8-64 nm depending on the nature of ferric and chromic salts used and dopant concentration. Pure mixed solids consisted of a mixture of α and γ-Fe2O3 phase whose crystallite size decreases by increasing the dopant concentrations. K2O-doping of the investigated systems resulted in the formation of K2FeO4 together with ferric oxide phases. Li2O-doping (0.5 and 0.75 mol %) led to the formation of LiFe5O8 together with γ-Fe2O3 phase. However, the heavily Li2O-doped samples consisted entirely of LiFe5O8. The SBET of pure system prepared from ferric and chromic sulphates measured higher SBET values as compared to those prepared from mixed nitrates, whereas K2O-doping decreased the SBET. On the other hand, Li2O-doping exerted a measurable increase in the SBET. The increase was however, more pronounced in case of the system prepared by using mixed sulphate solutions. The catalytic activity was higher in case of the catalysts prepared by using mixed nitrates as compared to the catalysts prepared by using mixed sulphate solutions. The doping process led to a progressive significant increase in the catalytic activity. The increase was, however, much more pronounced in case of the catalysts prepared from the mixed sulphates. The maximum increase in the k200°C value due to doping with 1.5 mol % K2O attained 30.8% and 285% for the solids prepared from mixed nitrates and mixed sulphates, respectively. These values measured 27% and 241% in case of the catalysts prepared by using mixed nitrate and mixed sulphate solutions, respectively. The doping process did not affect the mechanism of the catalyzed reaction but increased the concentrations of active sites involved in catalytic reaction without changing their energetic nature.
nanocrystalline
Fe2O3-Cr2O3
Doping and Catalytic behavior
2010
03
02
37
59
https://ejchem.journals.ekb.eg/article_1203_2086ad4b8734edc7b851430687ff8c95.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Comparative Study on Synthesis and Characterization of Ceria Based Composite Oxides Containing Manganese Nano-Particles
Mn/Ce nano-composite oxides containing different amounts of manganese (5, 9, 17, 23, 29, 34 wt% as MnO2) were prepared by impregnation method at various calcination temperatures. Effect of both thermal treatment and loading on the structural, surface and microstructure properties of the as prepared nano-composites was determined. The combined effect of manganese oxide and ceria, at different concentrations, strongly influences the previous properties of the nano-composite oxides, by dispersing the MnO2 phase and promoting the efficiency of the Ce4+- Ce3+ and Mn4+ - Mn3+ redox couples.
The thermal treatment and loading influenced the interaction between manganese and CeO
2 evidently. The incorporation of Mn ions into CeO2 crystal lattice resulted in weaker interaction between manganese and ceria on composite surface. Manganese loading at 400oC led to a slight increase in the ceria crystallite size which decreased by increasing the calcination temperature from 400 to 600oC. The sintering activation energy of ceria was evaluated to be 12kJ/mol for the MnO2/CeO2 nano-composite.
XRD
TEM
SBET and MnO2/CeO2 nano-composite
2010
03
02
61
76
https://ejchem.journals.ekb.eg/article_1204_c5bae39d27114f0296abad59c4cc4d9e.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Removal of Lead from Aqueous Solutions by Xerogel Film Supported on Activated Carbon and Silica
Marwa
Sherief
adly
Hanna
Eglal.
Souaya
Alaa
Abdelmoaty
CARBON xerogel (X), a kind of novel carbon material with low-density and continuous nano-porous structure that can be controlled and tailored on nanometer scale, has been prepared through the sol –gel polycondensation of resorcinol (R) with formaldehyde (F) followed by drying at ambient pressure and carbonization in inert atmosphere. Batch adsorption experiments were performed to find out the effective lead removal at different metal ion concentrations. Removal of lead from aqueous solutions by adsorption onto xerogel film supported on activated carbon and silica has been performed. The removal of Pb ions from aqueous solutions was studied by batch method. The effects of initial metal concentrations, initial pH, contact time and the quantity of adsorbents were investigated. It was found that carbon xerogel supported on activated carbon exhibited the best adsorption potential for removal of lead ions from solutions.
Lead removal
Xerogel
Activated carbon
Silica and Coating
2010
03
02
77
84
https://ejchem.journals.ekb.eg/article_1205_d8f327ffee3301b0a38bcda03101ce01.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Electrical and Structural Properties of Nickel Oxide - Containing Phosphate Glasses
PHOSPHATE glasses containing 0.05-7.5g NiO/100 glass were …. prepared using sodium di-hydrogen phosphate. The prepared glasse were investigated using IR, a.c. conductivity, dielectric constant (ε`) and the dielectric loss (ε``). IR spectra revealed that the Ni2+ ions are located near P=O. Addition of Na2O causes a breakdown of the ring type with the formation of more non-bridging oxygens and depolymerization of the network. The conductivity of Ni-containing glasses is more than that of Ni-free phosphate glass, and attain maximum value for glass containing 0.25 g NiO per 100g glass The relation between log σ and reciprocal of the temperature suggests that, the mechanism predominating in the high temperature region is ionic in nature, while it is electronic in origin in the low temperature region. Introducing NiO extends electronic conduction through hopping mechanism to the high temperature region particularly at high frequency. The dielectric constant′ and the dielectric loss ε `` increase with increasing temperature, while a decrease in′ with increasing frequency was observed.
Phosphate glasses
Nickel oxide-containing glasses
electrical conductivity
Dielectric constant and Dielectric loss
2010
03
02
85
99
https://ejchem.journals.ekb.eg/article_1206_ef27f11d56f569699632afd5ee83597b.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Spectrophotometric and Potentiometric Methods for the Determination of Cefprozil, Dropropizine and Tizanidine Hydrochloride in Pharmaceutical Preparations
TWO SIMPLE, accurate spectrophotometric and potentiometric m methods were developed for the determination of cefprozil, dropropizine and tizanidine hydrochloride in their pharmaceutical preparations. The spectrophotometric method is based on the selective oxidation of cefprozil or tizanidine with N-bromosuccinimide in an alkaline medium to give an intense yellow product with a maximum absorption at 396 or 384 nm, respectively. The reaction conditions were studied and optimized. The reaction obeyed Beer's law over the concentration range 5-40 and 10-80 g ml-1 for cefprozil and tizanidine hydrochloride, respectively. The potentiometric method involves the direct titration of cefprozil and dropropizine with N-bromosuccinimide in sulphuric acid medium and the end point is determined potentiometrically using platinum electrode. Cefprozil and dropropizine can be determined quantitatively in the concentration range of 0.13-1.30 and 0.118-1.180 mg with recovery values of 98.46-100.77 and 99.58-100.85% and relative standard deviations 0.39-0.54 and 0.52-0.87% for cefprozil and dropropizine, respectively. The proposed methods are applied for the determination of these drugs in pure forms and in pharmaceutical preparations.
Cefprozil
Dropropizine
Tizanidine hydrochloride
N-Bromosuccinimide
Spectrophotometry and Potentiometry
2010
03
02
101
115
https://ejchem.journals.ekb.eg/article_1207_ab12586f661fc6852bcd7184fb0fe301.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Corrosion Study of Glaze-Ceramics Doped Cement-Kiln-Dust Soaked in Concentrated HCl
NEW glaze-ceramics formulated from industrial waste have been ....... prepared. The method consists of introducing cement-kiln-dust (CKD) in the industrial glaze-ceramics with various ratios (10-50%) together with the addition of 10gm boric acid. The chemical durability of the prepared composite cement-dust-glaze-ceramics (CDGC) is investigated using high concentrations of (2,5 & 8N) HCl acid solutions. CDGC are vitrified by melting for four hours at 1400oC ± 250oC depending on the amount of CKD introduced. Specifically, the experimental results indicate that the introduction of CKD in industrial glaze decreases durability. At high HCl concentrations, the durabilities of the prepared glaze-ceramics are observed to decrease with increasing the percentage of (CKD) until certain limit and almost constancy. The corrosion results are explained according to the ion exchange mechanism and formation or dissociation of the modified depleted layer.
Some hollow and jogged areas are observed by SEM which might be interpreted as evidence of local corrosion phenomena. In addition, the pH values of the leachant solutions are measured. The comparison of hardness for the optimum glaze-ceramic and glaze-ceramic derivatives prepared in this study indicates a degradation % in their chemical and physical properties depending on the amount% of CKD introduced. It is observed that the degradation not only depends on the amount of CKD introduced, but also on the strength of the leaching HCl acid solution. Also, the results show that, the prepared glazes have a surface hardness values ranged from 5.5 to 2.5 in the Mohs scale.
CKD waste
New glaze-ceramics
Corrosion and Hardness
2010
03
02
117
135
https://ejchem.journals.ekb.eg/article_1208_0b5766c24569822a287e0ed12b307e12.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Synthesis, Spectroscopic Characterization, Thermal Investigation and Antimicrobial Activity of S, O and N-Donor Heterocyclic Schiff Base Ligands and their Co(II), Cd(II), Hg(II), Fe(III) and UO2(II) Metal Complexes
THE POLYDENTATE ligands 2,5-N,N-bis (dimethyl-1- ……phenyl-4-pyrazoline-5-one) furanidine; 2,5-N,N-bis (pyridine) furanidine and 2,5-N,N-bis (2-thiophenol) furanidine (L1 – L3), have been prepared and identified. The chemical behavior of these ligands towards some metal cations such as Co(II) Cd(II), Hg(II), Fe(III) and UO2(II) was studied. The isolated complexes are characterized using analytical data, IR, 1H-NMR, UV-visible, mass spectroscopy, magnetic susceptibility, thermal analysis and molar conductance measurements. Bonding of the ligands with the metal ions is deduced from IR spectra and the presence of the mononuclear complexes are inferred from the mass spectral study. An octahedral structure is proposed for the prepared metal complexes and some ligand field parameters (Dq, B, and β) in addition to LFSE were calculated from electronic spectral data. All synthesized compounds were screened for their antimicrobial activity against gram positive and gram negative bacteria and fungi. The biological evalution study showed high to moderate bacterial activity compared with the ligands, their metal complexes and known antibiotics data.
Heterocyclic ligands
Metal complexes
Thermal studies and Antimicrobial activity
2010
03
02
137
162
https://ejchem.journals.ekb.eg/article_1209_f05990ef3a45748258c1002976334acd.pdf
Egyptian Journal of Chemistry
Egypt. J. Chem.
0449-2285
0449-2285
2010
53
1
Density and Speed of Sound of Sodium Nitroprusside with Aqueous Alcohols
STUDIES on apparent molar volumes for the solutions of sodium sodi nitroprusside in aqueous solutions of methanol, ethanol and propanol in the temperature range 298.15 to 313K at 5K intervals have been determined from the density measurements of the solutions. Speed of sound of solutions of sodium nitroprusside in aqueous solutions of alcohols has also been experimentally determined at 303.15K.Molar isentropic compressibilities and apparent molar isentropic compressibilities have been calculated from the speed of sound data. These results have been used to calculate the following partial molar quantities :
, , V0 E 0s K
Various acoustic parameters and solvation number have been evaluated for sodium nitroprusside in different aqueous solutions of alcohols. The results are discussed in the light of solute- solvent and solute –solute interactions.
water
Alcohols
Sodium nitroprusside
Apparent molar volume
density
Solvation number
ultrasonic velocity
Molar isentropic compressibilities and Apparent molar isentropic compressibilities
2010
03
02
163
176
https://ejchem.journals.ekb.eg/article_1210_d741902aab3379edf139994b73fb1459.pdf