scholarly journals Spectroscopic and Substitution Kinetic Studies of Hexacyanoferrate(II) Complexes byEDTA Catalysed with Mercury(II)

2009 ◽  
Vol 6 (s1) ◽  
pp. S103-S110 ◽  
Author(s):  
K. S. Siddiqi ◽  
Aftab Aslam Parwaz Khan ◽  
Ayaz Mohd ◽  
Shaista Bano
Keyword(s):  
Kinetic Studies ◽  
Ligand Substitution ◽  
Kinetics And Mechanism ◽  
Inexpensive Method ◽  
Cyanide Ion ◽  
Dissociative Mechanism ◽  
Maximum Reaction ◽  
Rate Of Reaction ◽  
Potassium Hydrogen ◽  
Mechanism Of The Reaction

Kinetics and mechanism of substitution of cyanide ion in hexacyanoferrate(II) by EDTA catalysed by mercury(II) has been studied spectrophotometrically at 365 nm in potassium hydrogen phthalate buffer of pH = 5.0 and ionic strength, I = 0.1 M, maintained by (KNO3) at 25 °C. Effect of the pH and concentration of the EDTA, [Fe(CN)4-6] on the rate of reaction has been studied. The kinetics and mechanism of the reaction has been shown through dissociative mechanism. The mechanism of ligand substitution in the complex together with the kinetic data has been shown. The catalytic activity of mercury(II) has also been studied as a function of its concentration. The maximum reaction product was detected at pH = 5 after which a decline in absorption occurs followed by precipitation. It is an inexpensive method to identify and remove the cyanide ion in solution even in very low concentration of the order of 10-4M.

Kinetic studies of the substitution reactions of the cis-dihalotetracarbonylmanganate(I) ions

1969 ◽  
Vol 47 (8) ◽  
pp. 1311-1319 ◽  
Author(s):  
Frank E. Smith ◽  
Ian S. Butler
Keyword(s):  
Halogen Bond ◽  
Kinetic Studies ◽  
Reaction Rates ◽  
Atomic Weight ◽  
Substitution Reactions ◽  
Dissociative Mechanism ◽  
First Order ◽  
Rate Determining Step ◽  
Rate Of Reaction ◽  
Substrate Independent

The substitution reactions of (C2H5)4[cis-Mn(CO)4X2], where X = Br or I, with a variety of ligands, L, were observed to take place with the loss of halide ion, X−, to form cis-Mn(CO)4LX and (C2H5)4NX. The reaction rates in s-tetrachloroethane were first order in substrate, independent of both the nature and the concentration of L, and decreased with increasing atomic weight of the halogen. A dissociative mechanism involving the breaking of a manganese–halogen bond as the rate-determining step is proposed. It is postulated that the order of reactivity of the substrates is most probably the result of an entropy rather than an enthalpy effect. The substitution reactions of (C2H5)4N[cis-Mn(CO)4BrI] in s-tetrachloroethane were also studied kinetically and found to be first order in substrate and independent of the nature and concentration of L. The products of these reactions, however, were mixtures of cis-Mn(CO)4LBr and cis-Mn(CO)4LI, and (C2H5)4NBr and (C2H5)4NI. A solvent study of the reaction between (C2H5)4N[cis-Mn(CO)4Br2] and P(C6H5)3 indicated that the rate of reaction tended to increase with increasing polarity of the solvent.

Kinetics and Mechanism of the Reaction of 2-Mercaptobenzothiazole with N-(Cyclohexylthio)Phthalimide and Related Compounds

1972 ◽  
Vol 45 (6) ◽  
pp. 1513-1531 ◽  
Author(s):  
P. N. Son ◽  
K. E. Andrews ◽  
A. T. Schooley
Keyword(s):  
Thermal Instability ◽  
Room Temperature ◽  
Kinetic Studies ◽  
Kinetics And Mechanism ◽  
Related Compounds ◽  
Mechanism Of The Reaction

Abstract Kinetic studies show that 2-mercaptobenzothiazole (MBT) reacts faster with N-(cyclohexylthio)phthalimide (CPT) than with such accelerators as N-t-butyl-2-benzothiozolesulfenamide (BBTS) or 2-(4-morpholinothio)benzothiazole (OBTS). Furthermore, the reaction between N-(cyclohexylthio)-o-benzoic sulfimide (CTBS) and MBT is so fast that it reacts almost instantaneously even at room temperature. However, CTBS is not a good retarder due to its thermal instability.

Kinetics and mechanism of the reaction of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione

1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Activation Parameters ◽  
Enol Form ◽  
Kinetics And Mechanism ◽  
Kinetic Constants ◽  
Steric Factors ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.

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