lobna.nassr

Lobna Abdel-Mohsen Ebaid Nassr

Professor - Head Of Chemistry Department- Director of Quality Management Unit - Faculty of Science - Sohag University

Faculty of science

Address: Chemistry Department - Faculty of Science - Sohag University

52

Like

Publications Which contain the keyword: base hydrolysis


2018-11-28 22:55:16 Keywords base hydrolysis,
Kinetic Features of the Base Hydrolysis of Schiff Base Complexes
Kinetic Features of the Base Hydrolysis of Schiff Base Complexes This work deals with the preparation, characterization and kinetic studies on base hydrolysis of some Fe(II) Schiff base amino acid complexes.The prepared complexes were found to be of 1:2 or 1:1 stoichiometry and non – electrolytic character, solubility measurements of these complexes showed them as hydrophobic in nature. The base ... Read more

2018-11-18 11:22:30 Keywords solvent effect, Kinetics, methanol, acetone, base hydrolysis,
Kinetics, Reactivity, Initial–Transition State Analysis and Thermodynamic Parameters of Base-Catalyzed Hydrolysis of Coumalic Acid in Solvents of Different Polarities
Base-catalyzed hydrolysis of coumalic acid (COU) in aqueous-methanol and aqueous-acetone mixtures has been studied kinetically at temperature range from 283 to 313 K. Moreover, the change in the activation energy barrier of COU from water to water–methanol and water–acetone mixtures is estimated from the kinetic data. Solvent effects on reactivity trends have been analyzed into initial and transition state components. ... Read more

2018-11-27 23:52:20 Keywords 6-amino coumarin, base hydrolysis, Kinetics,
Synthesis of novel coumarin derivatives based on 6-aminocoumarin, kinetics inspection of base hydrolysis, and spectrophotometric tracer of intermediate progress
The kinetics of the base hydrolysis of 6-aminocoumarin and some of its derivatives was studied spectrophotometrically in aqueous medium at 298 K under pseudo-firstorder conditions ([OH-][[[Compound]). The suggested general rate equation can be given as: rate = {k1 ? k2 [OH-]} [complex]. The reasonable mechanism suggested that the investigated reaction proceeded via the formation of an intermediate and the ring ... Read more

2018-10-05 11:38:58 Keywords solvent effect, base hydrolysis, Chromen-2-ones, laser dyes,
Solvent and Temperature effects on Reactivity trends of Base-catalyzed hydrolysis of some Chromen-2-one laser dyes
In the present study, reactivity base-catalyzed hydrolysis of 7-dimethylamino-4-methyl-2H-chromen-2-one (DMAC) and 7-diethylamino-4-methyl-2H-chromen-2-one (DEAC) in binary aqueous-methanol and aqueous-acetone mixtures was examined at 298 K. Kinetic results, rate laws and reaction mechanisms were established. Moreover, the change in the activation energy barrier of the investigated compounds from water to water–methanol and water–acetone mixtures was estimated from the kinetic data. Base-catalyzed hydrolysis ... Read more

Solvent Effects on The reactivity Trends of some Coumarin Derivatives
Kinetic results, rate laws and reaction mechanisms were established for the base hydrolysis of 7-hydroxycoumarin (HC), 7-hydroxycoumarin-4-acetic acid (HCA), 6-nitrocoumarin (NC), 6-nitrocoumarin-3-carboxylic acid (NCC), 7-dimethylamino-4-methylcoumarin (DMAC), 7-diethylamino-4-methylcoumarin (DEAC) and coumalic acid (COU) in aqueous solution, water-methanol and water-acetone mixtures. The kinetics of the base hydrolysis followed a rate law with kobs= k2[OH-] for all coumarin derivatives under study except 6-nitrocoumarin-3-carboxylic ... Read more

Solvent effects on the kinetics and reactivity trends of base-catalyzed hydrolysis of some chromen-2-one indicator dyes at different temperatures
Base hydrolysis of 7-hydroxy coumarin (HC) and 7-hydroxy-coumarin-4-acetic acid (HCA) in aqueous-methanol and aqueous-acetone mixtures were studied kinetically at temperature range from 283 to 313 K. The activation parameters of the reactions were evaluated and discussed. Moreover, the change in the activation energy barrier of the investigated compounds from water to water-methanol and water-acetone mixtures was estimated from the kinetic ... Read more

2018-09-16 14:12:49 Keywords chromen-2-one, DMAC, base hydrolysis, DEAC, Reactivity Trend,
Kinetic study and reactivity trends of hydroxide ion attack on some chromen-2-one laser dyes in binary water-methanol and water-acetone mixtures
The kinetics of base-catalyzed hydrolysis of 7-dimethylamino-4-methyl-2_H_-chromen-2-one (DMAC) and 7-diethylamino-4-methyl-2_H_-chromen-2-one (DEAC) in binary water-methanol and water-acetone mixtures were studied in the temperature range from 288 to 313 K. The activation and thermodynamic parameters of these reactions were evaluated and discussed. The change in the activation energy in going from water to aqueous methanol and aqueous acetone was estimated from the ... Read more

Kinetic investigation of hydroxide ion attack at high spin Fe(II) bromosalicylidine chelates with amino acids in binary aqueous solvents: Initial and transition state analysis
We have investigated the kinetics of hydroxide ion attack at iron(II) chelates with 5-bromosalicylidene derivatives of amino acids (alanine, phenylalanine, aspartic acid, histidine, and arginine) in binary aqueous mixed solvents at 298 K. The observed reactivity trends are discussed in connection with the complexes hydrophobicity/hydrophilicity, transfer chemical potentials of hydroxide ion and the complex, and the solvent effects. Read more

Reactivity trends in the base hydrolysis of 6-nitro-2H-chromen-2-one and 6-nitro-2H-chromen-2-one-3-carboxylic acid  at different temperatures
Kinetics of the base hydrolysis of 6-nitro-2H-chromen-2-one (NC) and 6-nitro-2H-chromen-2-one-3-carboxylic acid (NCC) in water-methanol and water-acetone mixtures was studied at temperature range from 283 to 313 K. The activation parameters of the reactions were evaluated and discussed. The change in the activation barrier of the investigated compounds from water to water-methanol and water-acetone mixtures were estimated from the kinetic data. ... Read more

Reactivity trends of hydroxide ion attack on high spin Fe(II) complexes in some mixed aqueous solvents: Gibb’s Free Energy of Transfer and initial-transition state analysi
The kinetics of hydroxide ion attack on bis(bromosalicylidene alanate)iron (II) (bsali), bis(bromosalicylidene phenylalanate)iron(II) (bsphali), bis(bromosalicylidene aspartate)iron(II) (bsasi), (bromosalicylidene histidinate)iron(II) (bshi), bis(bromosalicylidene arginate)iron(II) (bsari) have been reported in different binary aqueous solvent mixtures at 298 K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic forms of the complexes investigated, as well as the transfer chemical potentials ... Read more