The Kinetics and Mechanism of Oxidation of the N-Substituted Urea-Titanium (III) Complexes by Iodine (AS I-3) in Ethanol and Acetonitrile
A.
Kamkar
Department of Chemistry, University of Tabriz, Tabriz, I.R. IRAN
author
J.P.
Day
Department of Chemistry, University of Manchester, M13 9PL, ENGLAND
author
text
article
1988
eng
The oxidation of complexes of Ti(III), (TiL6)3+ (L=ur, Meur, DMeur, DEture, N-Bu-ur, and Phur), by iodine as I3- in ethanol and acetonitrile solutions, appears to proceed as a second order reaction and is much faster in ethanol solution (where solvolysis occurs) than in acetonitrile. The enthalpy of activation appears to decrease as ligand's size increases which suggest that the kinetic stability of these compounds is not just because of steric hindrance; but electronic effect of the ligand must be more important.The mechanism of the reaction is suggested to be an inner redox reaction in which an electron transfers through a bridge which is formed by bonding I3- to the complex ion.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
3
12
https://ijcce.ac.ir/article_12266_308f379a850f87708ec1ed0640d197ff.pdf
dx.doi.org/10.30492/ijcce.1988.12266
Mechanism-Based Studies of the Active Site-Directed Inhibition and Activation of Enzyme Transketolase
Bijan
Farzami
Department of Biochemistry, School of Medicine, University of Tehran, Tehran, I.R. IRAN
author
text
article
1988
eng
Derivatives of phenyl-keto butenoic acids have been reported to be inhibitors of pyruvate decarboxylase, (PDC). The inhibition of transketolase, a thiamine requiring enzyme such as PDF, by meta nitrophenyl derivative of 2-oxo-3-butenoic acid (MNPB) is reported here. These studies indicate that the inhibitor binds to the enzyme at the active site. A two-step inhibition was observed, first the inhibitor reacts with the enzyme on one site- non-cooperative with Mg2+, and TPP, inhibiting the enzyme, second in higher concentration of the inhibitor an abrupt enhancement of the inhibition takes place. In the absence of cofactors, the lower concentration of the inhibitor caused an enhancement of activation to 150% of original enzyme activity followed by a drop to a low 50% in 60 minutes. Higher concentration of the inhibitor produced an inhibition with a half-life that was pronouncedly larger than when cofactors were present (). We conclude therefore that the enzyme contains a regulatory and a catalytic site with the regulatory site functional, without the aid of cofactors and that the cofactors are auxiliary for the action of the enzyme. The lowering effect of the reaction half-life by the cofactors is due to the rate enhancement caused by cofactors in the catalytic site of the enzyme.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
13
20
https://ijcce.ac.ir/article_12267_d9a4063910f88ee493571b393c39651c.pdf
dx.doi.org/10.30492/ijcce.1988.12267
Epicuticular Wax Ester of the Leaves of Scutellaria Laterif Lora L.
Shahram
Yaghmai
School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, I.R. IRAN
author
text
article
1988
eng
Subsequent to phytochemical investigation on scutellaria lateriflora (Labiatae) from Mazandaran provincein Iran, the wax ester fraction of the leaves has been investigated. Using TLC, CC GLC and GLC-MS, the alkyl esters of the epicuticular wax was analysed. Total concentration of the esters was 35% and it was shown to be composed of a homologous series having various chain lengths in the range of C34-C52 which are comprised of C16-C28 n-alkanols and C14-C26 n-acids. All the components are reported for the first time in the family labiatae.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
21
27
https://ijcce.ac.ir/article_12268_47b5a631512816f3f71907bdf844754e.pdf
dx.doi.org/10.30492/ijcce.1988.12268
Kinetic Study of the Linkage Isomers in [Co(NH3)5ONO]X2 (X=Cl¯, Br¯, I¯) in the Solid State in KBr Discs
Gholam Hossein
Heravi
Chemistry Department, Tehran University, Tehran, I.R. IRAN
author
Mansour
Abedini
Chemistry Department, Tehran University, Tehran, I.R. IRAN
author
text
article
1988
eng
The nitrite ® nitro isomerization in nitritopentaamine cobalt (III) halides has been known. In this paper, the effect of the size of the counter ions (noncoordinated groups) on the rate of isomerization in nitritopentaamine cobalt (III) halides, is reported. The rate of isomerization is decreased by increasing the size of the counter ions. This decrease is explained on the basis of steric interaction between the nitro groups in the inner sphere and the counter ions in the outer sphere of these complexes.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
28
32
https://ijcce.ac.ir/article_12273_0cad1764a30ff7360d69f25e1de88aed.pdf
dx.doi.org/10.30492/ijcce.1988.12273
Iterative Force-Field Calculation and Molecular Dynamics of Cyclooctanone
Mehran
Ghiaci
Department of Chemistry, Isfahan University of Technology, Isfahan, I.R. IRAN
author
text
article
1988
eng
Body's iterative force-field computer program has been used to calculate strain energies in cyclooctanone (I). 348 MHZ 1H NMR spectra of (I) have been investigated over the temperature range of 25° to -160°C. Two conformation processes affect the 1H NMR spectrum of (I). Iterative force-field calculations on the conformations and conformational interconversion paths of (I) give results consistent with the NMR findings.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
33
46
https://ijcce.ac.ir/article_12274_a90311ebf87a76408ac76632b4429dc2.pdf
dx.doi.org/10.30492/ijcce.1988.12274
Electronic Spectral Line Shape of a Diatomic Molecule
Reza
Islampour
Department of Chemistry University of Teacher Education, Tehran, I.R. IRAN
author
Ali
Maghari
Department of Chemistry University of Teacher Education, Tehran, I.R. IRAN
author
text
article
1988
eng
The electronic absorption spectral line shape of a diatomic molecule with harmonic potential curves is calculated using the time correlation function formalism. Both the equilibrium shift and the frequency shift of the two linking electronic states ate taken into account. The spectrum is also calculated using the cumulated expansion which is related to the correlation function of the time-dependent energy gap between the two electronic states.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
47
54
https://ijcce.ac.ir/article_12275_16a98d4df5e7bd568f08f78c907ff919.pdf
dx.doi.org/10.30492/ijcce.1988.12275
Design of Thickener by Computer
M.
Edalat
College of Chemical Engineering, Sharif University of Technology, Tehran, I.R. IRAN
author
H.
Toba
College of Chemical Engineering, Esfahan University of Technology, Isfahan, I.R. IRAN
author
text
article
1988
eng
A mathematical method for calculation of the minimum cross-sectional area of a thickener is presented by obtaining minimum laboratory batch settling test data, a function, which is called settling function, is derived. This function is found to be in the form of a polynomial of third order. The settling function and mass flux relation are used for the design of thickener. The method predicts the minimum cross-sectional area of a thickener in Tehran Chemical factory where sodium sulfate is produced. The results thus obtained are promising since they are more accurate than those found through commonly used graphical method.
Iranian Journal of Chemistry and Chemical Engineering
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
1021-9986
7
v.
1
no.
1988
55
58
https://ijcce.ac.ir/article_12276_6e5e959f8f53e5a719d4ed4200b6282c.pdf
dx.doi.org/10.30492/ijcce.1988.12276