http://blogs.najah.edu/author/maher-abu-eid An-Najah Blogs :: Maher Abdel Razzak Abu-Eid Natsheh en-us Sat, 27 Jul 2024 14:57:38 IDT Sat, 27 Jul 2024 14:57:38 IDT [email protected] [email protected] http://blogs.najah.edu/staff/maher-abu-eid/article/Kinetics-and-Mechanism-of-Oxidation-of-L-Cysteine-by-bis-3-di-2-pyridylketone-2-thiophenylhydrazone-IronIII-Complex-in-Acidic-MediumPublished Articles The kinetics oxidation of L-cysteine by 3-di-2-pyridylketone-2-thiophenylhydrazone-ironIII [FeDPKTH2] 3 complex in acidic medium was studied spectrophotometrically at 36C o temperature The differential rate method initial rate was served in this investigation The molar ratios of DPKTH to ironIII and ironII individually were found to be [2:1] [DPKTH : ironIIIII] The reaction was stroked to be first-order with respect to ironIII and L-cysteine second-order with respected to DPKTH ligand and reversed second-order with respected to hydrogen ion concentration Added salts did not affect the rate and no free radical was detected when radical detector was placed in the reaction mixture Ethanol solvent ratio was found to effect both the initial rate and the maximum absorbance max of [FeDPKTH2]2 complex The initial rate rose when the temperature was increased which empowered the activation parameters calculations From the evaluation of the obtained linear data a reaction mechanism is proposed which involves a pre-equilibrium of an adduct formation between L-cysteine and [FeDPKTH2]3 complex http://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-Determination-of-Tiopronin-in-PharmaceuticalPublished Articles Two spectrophotometric methods are described for the determination of tiopronin in pharmaceuticals They are based on the oxidation-reduction reaction between tiopronin and iron III then forming a complex between iron II and ferrozine or di-2-pyridyl ketone-2-thiophenoylhydrazone The produced colored iron II-ferrozine complex [system I] absorbs at 562 nm while the iron II-di-2-pyridyl ketone-2-thiophenoylhydrazone complex [system II] absorbs at 656 nm The effect of different factors such as: pH reagent concentration time of reaction temperature and the tolerance amount of the common excipients have been studied Applying the optimum working conditions tiopronin can be determined over the range 02-86 and 05-170 ppm and with molar absorptivities of 20x10 4 and 10x104 l mol-1cm-1 for systems I and II respectively Both methods offer high selectivity sensitivity and accuracy with a relative standard deviation RSD of less than 11 for five measurements The proposed methods were applied successfully for the determination of tiopronin in Captimer tablets http://blogs.najah.edu/staff/maher-abu-eid/article/Tandem-cycloaddition-retrocycloaddition-reaction-Formation-of-a-diazadioxabicyclononene-systemPublished ArticlesABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 22125-ORGN 25-ORGN Part 2 2001http://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-determination-of-nitrite-and-nitrate-using-phosphomolybdenum-blue-complexPublished Articles A method for spectrophotometric determination of nitrite and nitrate is described This method is based on the reduction of phosphomolybdic acid to phosphomolybdenum blue complex by sodium sulfide The obtained phosphomolybdenum blue complex is oxidized by the addition of nitrite and this causes a reduction in intensity of the blue color The absolute decrease in the absorbance of the blue color or the rate of its decrease is found to be directly proportional to the amount of nitrite added The absorbance of the phosphomolybdenum blue complex is monitored spectrophotometrically at 814 nm and related to the concentration of nitrite present The effect of different factors such as acidity stability of the complex time temperature phosphate concentration molybdenum concentration sodium sulfide concentration and the tolerance amount of other ions have been reported Maximum absorbance is at 814 nm The range of linearity using the conventional method is 0520 ppm with molar absorptivity of 11 104 l mol 1 cm1 and a relative standard deviation of 26 for five measurements The range of linearity using the conventional method is 0520 ppm with molar absorptivity of 11104 l mol1 cm1 and a relative standard deviation of 26 for five measurements The range of linearity using the reaction rate method is 0236 ppm with a relative standard deviation of 24 for five measurements The method is applied for determination of nitrite and nitrate in water meat products and vegetables 1999 Elsevier Science BV All rights reserved http://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-Determination-of-Cysteine-and-N-Acetylcysteine-in-Pharmaceutical-PreparationsPublished ArticlesAn accurate fast spectrophotometric method for the determination of cysteine and N-acetylcysteineis presented based on the oxidation of these amino acids by ferric ions in the presence of ferrozinewhereby a violet-coloured complex is formed which absorbs at 562 nm The method was satisfactory for thedetermination of cysteine and N-acetylcysteine in samples within the range 002-600 ggm1-1 Effectsof time acidity ferric ions ferrozine sodium perchlorate concentrations and the tolerance limit for other amino acids have been reported The method was applied to the determination of cysteine in amino acids mixtures and N-acetylcysteine in pharmaceutical preparationshttp://blogs.najah.edu/staff/maher-abu-eid/article/Emodin-A-Naturally-Occuring-Anthraquinone-Its-Isolation-and-Spectrophotometric-Determination-in-Rumex-Cyprius-Plant-Published ArticlesA new method for isolation and specrophotometric determination of emodin is presented Emodin was isolated by thin layer chromatography tlc and column chromatography cc techniques as an orange long crystalline substance Emodin exhibits two absorption maxima at 420 and 520 nm Stability of the color and the effect of pH were studied Beers law is obeyed in the range 2-30 ppm The method is applied to the determination of emodin in roots stems and leaves of Rumex cyprius plant http://blogs.najah.edu/staff/maher-abu-eid/article/A-catalytic-method-for-the-determination-of-trace-amounts-of-mercury-uptaken-by-broad-beams-plantsPublished ArticlesA new accurate fast catalytic method for the determination of trace amounts of mercury uptaken by plants is proposed The method is based on the catalytic effect of mercuryII on the rate of ligand-exchange reaction between ferrozine and hexacyanoferrateII whereby a coloured violet complex is formed which absorbs at 562 nm The method allows the determination of mercuryII in the range 005-40 ppm The effect of pH hexacyanoferrate ferrozine temperature time of reaction and tolerance limit of many ions have been reported The method is applied to the determination of mercuryII uptaken by broad beans plants irrigated with water containing different amounts of mercuryIIhttp://blogs.najah.edu/staff/maher-abu-eid/article/Preferential-Solvation-of-Fephen2CN2-in-Binary-Aqueous-Acetone-and-2-Methoxyethanol-MixturesPublished Articles Preferential solvation of bis-llO-phenanthroline-bis-cyanoironII was investigated in aqueous acetone and 2-methoxyethanol binary mixtures The solvatochromic behaviour is discussed in terms of donor and acceptor numbers The thermodynamic model of Frankel was used to treat http://blogs.najah.edu/staff/maher-abu-eid/article/PlumbaginPublished ArticlesDOI: 10108000387019408007247 Published in: Spectroscopy Letters Volume 27 Issue 4 May 1994 pages 409 - 416 Authors: Mohammed A Al-Nuri a; Mohammed A Hannoun a; Nidal A Zatar a; Maher A Abu-Eid a; Waheed J Al-Jondi a; Ahmad I Hussein a; Mohammed S Ali-Shtayeh b Abstract: A new method for isolation and spectrophotometric determination of plumbagin is presented Plumbagin was isolated by thin layer chromatography TLC and column chromatography CC techniques as an orange tinged yellow long crystalline substances Plumbagin exhibits two absrop-tion maxima at 410 and 510 nm Stability of the color pKa value and the effect of pH were studied Beers law is obeyed over the range 09-45 ppm The method is applied to the determination of plumbagin in roots stems and leaves of Plumbago europaea L plant Keywords: Plumbagin; Isolation; Spectrophotometric Determination; Roots; Stems; Leaves; Plumbago Europaea L; pKa; Acid-Base Indicator http:wwwinformaworldcomsmppcontent~db=all~content=a747184857?words=maher|abu|eid http://blogs.najah.edu/staff/maher-abu-eid/article/A-New-Method-for-the-Preparation-of-PolySilmethylene-as-a-Precursor-for-Silicon-Carbide-FibersPublished ArticlesPolysilincthylene has been prepared form 3-chloropropyltrichlorosilane The structure of polysihnethylene was investigated by JR and NMR spectroscopy The pyrolysis of the polymer was studied by Thermal Gravimetric Analysis TGA and was found to give 70 ceramic yield after pyrolysis temp of 900Chttp://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-Determination-of-Uranium-with-Di-2-Pyridyl-Ketone-BenzoylhydrazonePublished ArticlesA method for the spectrophotometric determination of uranium Vi by complexation with di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution is described Uranium VI forms a 1:2 complex with DPKBH The complex has a maximum absorbance at 377 nm Beers law is obeyed over the range 02 - 12 g m-1 The effect of pH excess reagent percentage of ethanol vv stability of the complex and the tolerance limit of many metal ions and common anions have been reported The method has been applied to the determination of uranium in Egyptian monazite sandhttp://blogs.najah.edu/staff/maher-abu-eid/article/Polymerization-of-4-Methylpentene--1--by-the-Mgc12-Ieb-Itici4-ImIbu3-Catalyst-System-1-Kinetic-Investigations-Published ArticlesThe kinetics of the polymerization of 4-methylpentcne-1- with the MgC12|EB|Ticl4|AliBu3 catalyst systems have been investigated The conditions and requirements to achieve the highest activity and stereospecificity of the MgC12-supported catalyst systems were discussed Moreover the role of aluminum alkyl and ethyl benzoate on the activity and stereo-regularity of the polymers have been reportedhttp://blogs.najah.edu/staff/maher-abu-eid/article/A-Sensitive-Catalytic-Method-for-the-Determination-of-Copper-by-Its-Catalytic-Effect-on-the-Potassium-Bromate-Indigo-Carmine-Reaction-Published ArticlesA method for catalytic determination of copper II is presented The method is based on the catalytic effect of copperII on the rate of oxidation of indigo carmine by potassium bromate The method is satisfactory for the determination of copperII in the range 12 to 38 ngmL Effect of acidity indigo carmine potassium bromate temperature and tolerance limits of foreign ions are reported The method was applied to the determination of copper in synthetic and in various milk samples Instrumentation Science Technology Volume 22 Issue 4 November 1994 pages 355 - 363 http:wwwinformaworldcomsmppcontent~content=a747149902~db=allhttp://blogs.najah.edu/staff/maher-abu-eid/article/Polymerization-of-4-Methylpentene--1-by-Using-the-MgCl2EbTiCl4AliBu3-Catalyst-System-2-Active-Centre-DeterminationPublished ArticlesIn the polymerization of 4-methylpentene- 1- by using the MgC12 IEB I TiCL4 IA1iBu3 catalyst systems the effect of catalyst composition on the number of active centres propagation rate constant rates of transfer and rate constants for transfer with respect to adsorbed aluminum alkyl and monomer have been reported The role of aluminum alkyl on the rate of polymerization and the effect of ethyl benzoate on the number of active centres and rate of transfer with respect to aluminum alkyl have been discussedhttp://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-Determination-of-Uranium-in-Ores-Using-Di-2-Pyridyl-Ketone-Hydrazone-Derivatives-Published ArticlesTwo methods for the spectrophotometric determination of uranium VI are described The methods are based on the formation of colored complexes for uranium VI with 1di-2-pyridyl ketone nicotinoylhydrazone DPKNH and 2di-2-pyridyl ketone thiophenoylhydrazone DPKTH in 50 vv ethanolic solution The complexes formed a uranium VI: complexing reagent mole ratio of 1:2 Maximum absorbance is at 373 nm for UVIDPKNH and at 389 nm for UVI - DPKTH Ranges of linearity effect of pH effect of excess reagent stability of the complexes and the tolerance limit for many metal ions and common anions have been reported The two methods have been applied to the determination of uranium in eygeptian monazite sand http://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-determination-of-cobalt-in-aqueous-solution-using-di-2-pyridyl-ketone-derivativesPublished ArticlesA method for the spectrophotometric determination of cobaltII is presented with a comparison of the binary complexes formed by cobaltII with di-2-pyridyl ketone nicotinoylhydrazone DPKNH di-2-pyridyl ketone 2-thiophenoylhydrazone DPKTH and di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution CobaltII forms 1: 2 complexes with the three reagents Maximum absorbance is at 372 nm for CoII- DPKNH at 389 nm for CoII-DPKTH and at 370 nm for CoII-DPKBH Analytica chimica acta 1992 vol 259 no1 pp 175-179 17 refhttp://blogs.najah.edu/staff/maher-abu-eid/article/Synthesis-of-polysilane-polymer-precursors-and-their-pyrolysis-to-silicon-carbidesPublished ArticlesOrganosilane polymers of the type SiR1R2n were prepared by dehydrochlorination of R1R2SiCl2 R1 = Me; R2 = H Et Prp But Hex Oct Ph with sodium in toluene as solvent The decomposition temperature yield soldubility and appearance were found to depend strongly on molecular structure The pyrolysis of polymethylsilane was found to give a 60 ceramic yield after thermal processing at 750Chttp://blogs.najah.edu/staff/maher-abu-eid/article/Kinetic-Studies-on-the-Hydrolysis-of-Pyrrolidene-Benzoylhydrazone-and-Thiophenylidene-B-enzoylhydrazonePublished ArticlesThe influence of the nature of acidic medium on the kinetics and the mechanism of the hydrolysis of pyrrolidenc bcnzoylhydrazone PBH and thiophenylidene benzoylhydrazone TBH has been studied The observed rate constants activation energy and thermodynamic parameters for the hydrolysis of PBH and TBH in tetraoxalate buffer solutions at 35C have been measured These results were compared with that reported for furfurylidene benzoylhydrazone FBH and the effect of heteroatom on the hydrolysis has been investigated In presence of tetraoxalate buffer as a hydrolysis medium for TBH the catalytic rate constants with respect to H F{C204 and H2C204 were calculated An equation relating the observed rate constant to the concentration of all species in the buffer mixture has been constructedhttp://blogs.najah.edu/staff/maher-abu-eid/article/Polymerization-of-Ethylene-by-the-Silaned-Sio2-mdashMgIbu2-mdashT1c14mdash-AlIbu3-Catalyst-SystemPublished ArticlesThe polymerization of ethylene was conducted over the Silaned Si02 MgiBu2 I TiCl I Al mu3 and over the Stauffer AA type 11Al iBu3 catalyst systems at 60 C The activity of the Sb2 supported catalyst was about one hundred times higher than that of Stauffer AA The rate time profiles for both catalysts were found to be of acceleration type The dependence of the spontaneous rate of polymerization with [Al mu3 I has been established for the Si02 supported catalyst A maximum rate was achieved at Al: Ti ratio of 512:1 The rate of ethylene production using Si02 supported catalyst was increased by a factor of two when the prepolymerization time with propylene was 10 minuteshttp://blogs.najah.edu/staff/maher-abu-eid/article/Spectrophotometric-Determination-of-Cobalt-with-Di-2-Pyridyl-Ketone-Benzoylhydrazone-Published ArticlesA method for the spectrophotometric determination of cobalt II by complexation with di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution is described Cobalt II forms a 1:2 complex with DPKBH The complex has maximum absorbance at 370 nm Beers law is obeyed over the range 01 - 28 gml-1 The effect of pH effect of excess reagent stability of the complex and the tolerance limit of many metal ions have been reported The method is applied to the determination of cobalt in different alloys containing other metals ions http://blogs.najah.edu/staff/maher-abu-eid/article/Kinetics-and-Mechanism-of-the-Hydrolysis-of-Benzylidene-Benzoylhyd---Razone-DerivativesPublished ArticlesThe kinetics and mechanism of hydrolysis of a series of substituted benzylidene benzoylhydrazones X - BBH have been studied at five different temperatures in the range 25 - 45c by UV -visible spectrophotometry The hydrolysis reactions were found to follow first - order kinetics A mechanism has been postulated in which the attack of water on the protonated substrate is subject to general base catalysis This mechanism has been supported by the effect of anion concentration of buffer at constant pH on the observed rate constant The Bronsted value for the hydrolysis reaction is 073 Hammett correlations Arrhenius and thermodynamic parametres have been evaluated and discussed The pKa values for the conjugate acids for benzylidene benzoylhydrazones derivatives X - BBH have been determinedhttp://blogs.najah.edu/staff/maher-abu-eid/article/The-Role-of-Solvent-on-the-Kinics-and-Mechanism-of-the-Hydrolysis-of-Slicylidene-Benzoyl-HydrazonePublished ArticlesThe effect of various solvents on the kinetics and mechanism of the hydrolysis of Salicylidanebenzoyl hydrazone SBH has been studied at five different temperatures 1745 C using UV and visible spectrophotometry In both protic and aprotic solvents the hydrolysis rates follows first order kinetics The role of solvent on the reaction rate thermodynamic parameters and mechanism have been reported and discussedhttp://blogs.najah.edu/staff/maher-abu-eid/article/The-polarographic-behaviour-of-salicylaldehyde-2-pyridylhydrazonePublished Articles The polarographic behaviour of salicylaldehyde-2-pyridylhydrazone SAPH has been studied in aqueous buffer solution containing 40 ethanol using DC and DP polarographic methods In the pH range 18--75 the observed single irreversible reduction wave is assigned to the splitting of the N--N bond and reduction of C=N centre In alkaline medium a second wave appears at a more negative potential due to the reduction of the salicylaldehyde which is formed by hydrolytic decomposition of the SAPH molecule The effect of pH on the limiting current and E12 as well as the reduction mechanism are discussed and compared with similar compounds The kinetic parameters of the electrode reaction have been calculated The analytical properties of the copperII-SAPH system is described The complex gave rise to a single irreversible well-defined wave E12---058 V at pH--52 The reaction process is diffusion controlled A method is suggested for the determination of CuII in presence of different metal ions as the difference in their E12 values is sufficient for the purpose http://blogs.najah.edu/staff/maher-abu-eid/article/Kinetic-Studies-of-the-Hydrolysis-of-Furfurylidene-BenzoylhydrazonePublished Articles The hydrolysis of furfurylidene benzoylhydrazone FBH in hydrochloric acid medium has been found to follow specific acid catalysis whereas the hydrolysis in universal buffer medium has been found to follow general acid-base catalysis Mechanisms for the hydrolysis in different acidic media have been postulated The observed rate constants secondary rate constants activation and thermodynamic parameters for the hydrolysis of furfurylidene benzoylhydrazone have been reported The effect of change in percentage of ethanol in the ethanol-buffer mixture on the rate of hydrolysis has been discussed http://blogs.najah.edu/staff/maher-abu-eid/article/Hydrosilylation-reactions-catalysed-by-decacarbonyldimanganese0Published ArticlesEvaluation en tant que catalyseur de Mn2CO10 pour les ractions dhydrosilylation de lhexne-1 avec des silanes tertiaires Et3SiH et EtO3SiHhttp://blogs.najah.edu/staff/maher-abu-eid/article/Polarographic-Behavior-of-Salicylaldehyde-2-Pyridylhydrazone-and-its-CopperIi-ComplexPublished ArticlesThe polarographic behaviour of salicylaldehyde-2-pyridylhydrazone SAPH has been studied in aqueous buffer solution containing 40 ethanol using DC and DP polarographic methods In the pH range 1875 the observed single irreversible reduction wave is assigned to the splitting of the N-N bond and reduction of C=N centre In alkaline medium a second wave appears at a more negative potential due to the reduction of the salicylaldehyde which is formed by hydrolytic decomposition of the SAPH molecule The effect of pH on the limiting current andE 12 as well as the reduction mechanism are discussed and compared with similar compounds The kinetic parameters of the electrode reaction have been calculated The analytical properties of the copperII-SAPH system is described The complex gave rise to a single irreversible well-defined wave E 12=058 V at pH=52 The reaction process is diffusion controlled A method is suggested for the determination of CuII in presence of different metal ions as the difference in theirE 12 values is sufficient for the purpose http://blogs.najah.edu/staff/maher-abu-eid/article/Some-Arylidene-2-Pyridylhydrazone-Derivatives-as-Reagents-for-Spectrophotometric-Determination-of-Palladium-Published ArticlesDOI: 10108000032718608064533 Published in: Analytical Letters Volume 19 Issue 19 20 1986 pages 1881 - 1891 Authors: Nidal Zatar a; Ali Z Abu Zuhri a; Maher Abu Eid a; FouaD Mahmoud a Abstract: A method for spectrophotometric determination of palladium by complexation with Arylidene-2-pyridylhydrazone derivatives in 50 VV ethanolic solution are described-PdII forms a 1:1 complex with the reagents Beers law is obeyed over the range 02-65 g ml-1 The effect of pH effect of excess reagent stability of complexes as well as the tolerance amount of many metal ions have been reported The method is applied with fair accuracy to the determination of pdII in synthetic solutions Keywords: Palladium II; Arylidene-2-Pyridylhydrazone; Spectrophotometric Determination http:wwwinformaworldcomsmppcontent~db=all~content=a762672811?words=maher|abu|eidhttp://blogs.najah.edu/staff/maher-abu-eid/article/Polymerization-of-4-ndash-Methylpentene---1-with-MagnesiummdashChloridemdashSupported-CatalystsPublished ArticlesNo Abstracthttp://blogs.najah.edu/staff/maher-abu-eid/article/Transition-Metal-Alkyl-Polymerization-mdash-Progress-and-DevelopmentPublished ArticlesProgress in the development of transition metal catalysts for the polymerization of ethylene and -olefins is reviewed and analyzed Further developments involving the use of supported catalysts are detailed and some of the fundamental catalaystforming reactions are discussed So recent kinetic and active centre concentration determinations on the polymerization of 4methylpentene 1 by catalysts of the type TiCl3033A1C13AliBu3 and supported catatysts of the type MgCl2 EB TiCl4-AliBu3 are reported and the results analyzed The much higher activities obtained with MgCl2supported catalysts are shown to arise from a significant increase in the concentration of active centres together with some increase in the propagation rate constanthttp://blogs.najah.edu/staff/maher-abu-eid/article/Comparative-Studies-on-Active-Centre-Determination-in-Ziegler-Natta-CatalysisPublished ArticlesThe development of new high activity catalysts has highlighted the need for improved methods for the determination of active centre concentrations in Ziegler-Natta catalysis Although a number of methods have been used by various researchers 12 very little work on the comparative evaluation of these methods has been carried out 345 The present work concerns some aspects of inhibition and kinetic studies for the polymerization of propylene and quenching and radio-tagging studies for the polymerization of 4-methyl pentene1