The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Akbar Afshar Assl - One of the best experts on this subject based on the ideXlab platform.
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Sensitive spectrophotometric determination of trace quantities of phenylhydrazine
Microchemical Journal, 2001Co-Authors: Abaas Afkhami, Akbar Afshar AsslAbstract:Abstract A method for the rapid and accurate determination of trace quantities of phenylhydrazine based on its inhibition effect in the reaction between bromate and hydrochloric acid is developed. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. The method allows the determination of phenylhydrazine in the range 4.60×10−7–7.40×10−5 M. The relative standard deviation for 10 determinations of 1.10×10−5 M phenylhydrazine is 0.97% and the detection limit of the method is 1.85×10−7 M. The method is applied to the determination of phenylhydrazine in water.
Pietro Tundo - One of the best experts on this subject based on the ideXlab platform.
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Insight into the hard-soft acid-base properties of differently substituted Phenylhydrazines in reactions with dimethyl carbonate.
The journal of physical chemistry. B, 2008Co-Authors: Anthony E. Rosamilia, Fabio Arico, Pietro TundoAbstract:Following the preliminary studies on the reactivity of the ambident nucleophile phenylhydrazine with dimethyl carbonate, investigations involving para-substituted Phenylhydrazines were carried out in order to probe differences in the reactivity within this class of nucleophile. Phenylhydrazines substituted by electron withdrawing or donating substituents showed an increase in reactivity of the phenylhydrazine toward dimethyl carbonate. Under the basic conditions used, all Phenylhydrazines displayed hard nucleophilicity, signifying that para-substitution on the phenyl ring has little effect on the hard−soft behavior of this class of nucleophile. This conclusion fits well within the results previously obtained using other para-substituted nucleophiles, i.e., phenols.
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Reaction of the ambident electrophile dimethyl carbonate with the ambident nucleophile phenylhydrazine.
The Journal of organic chemistry, 2008Co-Authors: Anthony E. Rosamilia, Fabio Arico, Pietro TundoAbstract:To explore the ambident electrophilic reactivity of dimethyl carbonate (DMC), reactions with the ambident nucleophile phenylhydrazine were investigated. When a Bronsted base was used, selective carboxymethylation occurred at N-1, after that several other compounds were produced selectively utilizing various conditions. Formation of these compounds was explained by using the Hard−Soft Acid−Base (HSAB) theory. Catalysis by some metal salts altered the reactivity of phenylhydrazine, which effected selective carboxymethylation at N-2 of phenylhydrazine instead.
Abaas Afkhami - One of the best experts on this subject based on the ideXlab platform.
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Sensitive spectrophotometric determination of trace quantities of phenylhydrazine
Microchemical Journal, 2001Co-Authors: Abaas Afkhami, Akbar Afshar AsslAbstract:Abstract A method for the rapid and accurate determination of trace quantities of phenylhydrazine based on its inhibition effect in the reaction between bromate and hydrochloric acid is developed. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. The method allows the determination of phenylhydrazine in the range 4.60×10−7–7.40×10−5 M. The relative standard deviation for 10 determinations of 1.10×10−5 M phenylhydrazine is 0.97% and the detection limit of the method is 1.85×10−7 M. The method is applied to the determination of phenylhydrazine in water.
Alexander J. Fatiadi - One of the best experts on this subject based on the ideXlab platform.
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The reaction of phenylhydrazine with squaric acid: a model for carbohydrate osazone formation
Carbohydrate Research, 1993Co-Authors: Hassan S. El Khadem, M. Ashraf Shalaby, Bruce Coxon, Alexander J. FatiadiAbstract:Abstract The reaction of squaric acid ( 1 ) with phenylhydrazine yields cyclobutanetetraone poly(phenylhydrazones) ( 2–4 ), as reported earlier, as well as squaric acid derivatives, reported here. The latter products are a salt, 1,3-dianilinocyclobutenediylium-2,4-diolate ( 5 ), and 1-anilino-2-phenylhydrazinocyclobutene-3,4-dione ( 6 ), which upon oxidation yields tautomeric forms of cyclobutanetetraone 1-anilide-2-phenylhydrazone ( 7a and 7b ). The structure of the compounds isolated was established by 1 H, 13 C, 2D COSY, and 2D J -resolved NMR spectroscopy. The similarity between the reaction of squaric acid ( 1 ) with phenylhydrazine and osazone formation can be seen from the analogy between compounds 2 , 6 , and 7b and intermediates produced during carbohydrate osazone formation, as well as from the fact that these compounds afford an osazone analog ( 4 ) when treated with phenylhydrazine. It was also found that compound 5 can be generated by a retro-osazone reaction when cyclobutanetetraone bis(phenylhydrazone) ( 2 ) is heated with aniline.
Kh Alizad - One of the best experts on this subject based on the ideXlab platform.
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a spectrophotometric flow injection method for determination of ultratrace amounts of phenylhydrazine by its inhibition effect on the reaction of thionin and nitrite
Journal of Chemistry, 2013Co-Authors: Mohsen Keyvanfard, Kh AlizadAbstract:A simple flow injection colorimetric procedure for determining phenylhydrazine was established. It is based on the reaction of phenylhydrazine in sulfuric acid with thionin and sodium nitrite. Reaction was monitored spectrophotometrically by measuring thionin absorbance at
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a spectrophotometric flow injection method for determination of ultratrace amounts of phenylhydrazine by its inhibition effect on the reaction of thionin and nitrite
Journal of Chemistry, 2013Co-Authors: Mohsen Keyvanfard, Kh AlizadAbstract:A simple flow injection colorimetric procedure for determining phenylhydrazine was established. It is based on the reaction of phenylhydrazine in sulfuric acid with thionin and sodium nitrite. Reaction was monitored spectrophotometrically by measuring thionin absorbance at