Kinetics of oxidation of nitrite by aqueous bromine

1973 ◽  
Vol 26 (9) ◽  
pp. 1847 ◽  
Author(s):  
JN Pendlebury ◽  
RH Smith
Keyword(s):  
Perchloric Acid ◽  
Acetate Buffer ◽  
Stopped Flow ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
Rate Laws ◽  
Temperature Dependences ◽  
Ph Range ◽  
Kinetics Of

The kinetics of oxidation of nitrite to nitrate by aqueous bromine have been investigated using a spectrophotometric stopped flow technique. In the pH range 4.2-5.8 (acetate buffer) the rate law is: - d[Br21,/dt = [Br21[N02 -I2 (a + b/[Br-1) (where [Br,], = [Br2]+[Br,-1) with a = (4.61-0-1) x lo4 l2 m01-~ s-l and b = (3.3 1-0.1) x lo4 1. mol-l s-l at 298.2 K and with the temperature dependences, - R d(lna)/d(l/T) = (46k 4) kJ mol-l and - R d(ln b)/d(l/T) = (45 k 2) kJ mol-'. In the pH range 0.8-2.5 (perchloric acid) the rate law is : - d[Br2],/dt = [HN0212[Br21 (w + v/[Br-l)/(l+ z[H+ItBr,l,) with w = (5.9+0.2)x lo4 l2 m01-~ s-l, v = (3.41-0.1)~ lo4 1, mol-l s-I, and z = (1.90i 0.06) x lo7 l2 mol-2 at 298.2 K. In addition: - R d ln(w/z)/d(l/T) = (31 1 4 ) kJ mol-I and - R d ln(v/z)/d(l/T) = (46 f 4) kJ mol-l In the pH range 2.8-3.3 (chloroacetate buffer) a combination of these two rate laws adequately describes the kinetic results. These rate laws have been interpreted in terms of two reversible initial reactions: 6) NO2- +Br2 + N02Br +Br- (followed by attack on N02Br by NO2-) (ii) NO2-+NO2- (or HNOJ + N204'- (or HN204-) (followed by attack by Br2 upon N204'- or HNZO4- or upon N203 formed from HN204-).

Kinetics of oxidation of thiocyanate by aqueous iodine

1973 ◽  
Vol 26 (9) ◽  
pp. 1863 ◽  
Author(s):  
GT Briot ◽  
RH Smith
Keyword(s):  
Rate Constants ◽  
Activation Energies ◽  
Stopped Flow ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
General Base ◽  
Present Rate ◽  
Rapid Equilibrium ◽  
Ph Range ◽  
Kinetics Of

The kinetics of oxidation of thiocyanate to sulphate by aqueous iodine in the pH range 9.2-12.5 have been studied using a spectrophotometric stopped flow technique. The reaction is general base-catalysed, having the rate law ��������������������� -d[I2]a/dt = ([SCN-][I3-]/[I-]2)Σ kB[B] where [I2]a is the total analytical concentration of iodine, [B] is the concentration of base, and where the summation is taken over all bases present. Rate constants, kB, and activation energies have been measured for the bases, OH-, PO43- and CO32-. ��� A mechanism involving the initial steps ����������������� I2+SCN- ↔ ISCN+I- �����������������(rapid equilibrium) ������������� ISCN+H2O+B → HOSCN+I- + HB+ �����������(rate determining) followed by rapid reactions of HOSCN with itself or with iodine is proposed.

Kinetics of Oxidation of Ferrocyanide by lodate Ion

1974 ◽  
Vol 52 (11) ◽  
pp. 2001-2004 ◽  
Author(s):  
Y. Sulfab ◽  
Hamid A. Elfaki
Keyword(s):  
Activation Energy ◽  
Ionic Strength ◽  
Formation Constant ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
Ph Range ◽  
Kinetics Of ◽  
Rate Determining Steps

In the presence of vast excess of ferrocyanide, over the pH range 1.76–2.65, the reaction between iodate and ferrocyanide ions follows the rate law[Formula: see text]where ka and kb have values of 1.97 × 103 M−2 min−1 and 4.08 × 105 M−3 min−1, respectively, at an ionic strength of 1.18 M and a temperature of 25.0 ± 0.1 °C. K1 is the formation constant of monoprotonated ferrocyanide. The "overall activation energy" of the reaction was found to be 15.8 kcal/mol. Rate-determining steps consistent with the kinetics have been proposed.

A KINETICS AND MECHANISTIC STUDY OF THE OXIDATION OF L-ARGININE BY QDC IN DMF-WATER MEDIUM

2021 ◽  
pp. 11-12
Author(s):  
Deepika Jain ◽  
Shilpa Rathor
Keyword(s):  
Perchloric Acid ◽  
Reaction Rate ◽  
Main Product ◽  
Activation Parameters ◽  
Reaction Rates ◽  
Mechanistic Study ◽  
Water Medium ◽  
Volume Percentage ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The present paper describes the kinetics of oxidation of l-Arginine by QDC in the presence of perchloric acid in 30% DMF-H O(v/v) medium at 2 + 40⁰C spectrophotometrically at λ =354nm. The reaction is rst order with respect to [QDC], [H ], and [substrate]. The reaction rate increased with max increasing volume percentage of DMF in reaction mixture. Michaelis- Menten type kinetic was observed with l-Arginine. The reaction rates were studied at different temperature and the activation parameters has been computed. The main product was identied as Cr (III) and 4-Guanidino buteraldehyde.

scholarly journals A study of the oxidation of butan-1-ol and propan-2-ol by nicotinamide-adenine dinucleotide catalysed by yeast alcohol dehydrogenase.

1975 ◽  
Vol 147 (3) ◽  
pp. 541-547 ◽  
Author(s):  
C J Dickenson ◽  
F M Dickinson
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ternary Complexes ◽  
Kinetics Of Oxidation ◽  
Yeast Alcohol Dehydrogenase ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Ph Range ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Flow Experiments

1. The kinetics of oxidation of butan-1-ol and propan-2-ol by NAD+, catalysed by yeast alcohol dehydrogenase, were studied at 25 degrees C from pH 5.5 to 10, and at pH 7.05 from 14 degrees to 44 degrees C, 2. Under all conditions studied the results are consistent with a mechanism whereby some dissociation of coenzyme from the active enzyme-NAD+-alcohol ternary complexes occurs, and the mechanism is therefore not strictly compulsory order. 3. A primary 2H isotopic effect on the maximum rates of oxidation of [1-2H2]butan-1-ol and [2H7]propan-2-ol was found at 25 degrees C over the pH range 5.5-10. Further, in stopped-flow experiments at pH 7.05 and 25 degrees C, there was no transient formation of NADH in the oxidation of butan-1-ol and propan-2-ol. The principal rate-limiting step in the oxidation of dependence on pH of the maximum rates of oxidation of butan-1-ol and propan-2-ol is consisten with the possibility that histidine and cysteine residues may affect or control catalysis.

Kinetics of the reversible association of ribosomal subunits: Stopped-flow studies of the rate law and of the effect of Mg2+

1975 ◽  
Vol 93 (4) ◽  
pp. 499-515 ◽  
Author(s):  
A. Wishnia ◽  
A. Boussert ◽  
M. Graffe ◽  
Ph. Dessen ◽  
M. Grunberg-Manago
Keyword(s):  
Stopped Flow ◽  
Ribosomal Subunits ◽  
Rate Law ◽  
Reversible Association ◽  
Kinetics Of

KINETICS OF THE OXIDATION OF URANIUM (IV) BY IRON (III) IN AQUEOUS SOLUTIONS OF PERCHLORIC ACID

1955 ◽  
Vol 33 (12) ◽  
pp. 1780-1791 ◽  
Author(s):  
R. H. Betts
Keyword(s):  
Electron Transfer ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Perchloric Acid ◽  
Rate Constants ◽  
Kcal Mole ◽  
Kinetics Of Oxidation ◽  
Temperature Coefficients ◽  
Kinetics Of ◽  
Rate Controlling Step

The kinetics of oxidation of uranium (IV) by iron (III) in aqueous solutions of perchloric acid have been investigated at four temperatures between 3.1 °C. and 24.8 °C. The reaction was followed by measurement of the amount of ferrous ion formed. For the conditions (H+) = 0.1–1.0 M, ionic strength = 1.02, (FeIII) = 10−4–10−5 M, and (UIV) = 10−4–10−5 M, the observed rate law is d(Fe2+)/dt = −2d(UIV)/dt[Formula: see text]K1 and K2 are the first hydrolysis constants for Fe3+ and U4+, respectively, and K′ and K″ are pseudo rate constants. At 24.8 °C., K′ = 2.98 sec.−1, and K″ = 10.6 mole liter−1 sec−1. The corresponding temperature coefficients are ΔH′ = 22.5 kcal./mole and ΔH″ = 24.2 kcal./mole. The kinetics of the process are consistent with a mechanism which involves, as a rate-controlling step, electron transfer between hydrolyzed ions.

scholarly journals A study of the kinetics and mechanism of rabbit muscle l-glycerol 3-phosphate dehydrogenase

1974 ◽  
Vol 143 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Philip Bentley ◽  
F. Mark Dickinson
Keyword(s):  
Basic Mechanism ◽  
Kinetics And Mechanism ◽  
Dihydroxyacetone Phosphate ◽  
Rabbit Muscle ◽  
Kinetics Of Oxidation ◽  
Mechanism Of Catalysis ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Ph Range ◽  
Kinetics Of

1. The kinetics of oxidation of l-glycerol 3-phosphate by NAD+and of reduction of dihydroxyacetone phosphate by NADH catalysed by rabbit muscle glycerol 3-phosphate dehydrogenase were studied over the range pH6–9. 2. The enzyme was found to catalyse the oxidation of glyoxylate by NAD+at pH8.0 and the kinetics of this reaction were also studied. 3. The results are consistent with a compulsory mechanism of catalysis for glycerol 3-phosphate oxidation and dihydroxyacetone phosphate reduction in the intermediate regions of pH, but modifications to the basic mechanism are required to fully explain results at the extremes of the pH range, with these substrates and for glyoxylate oxidation at pH8.0.

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