ChemInform Abstract: Nucleophilic Addition to Olefins. Part 23. High Intrinsic Rate Constant and Large Imbalances in the Thiolate Ion Addition to Substituted α-Nitrostilbenes.

ChemInform ◽  
1989 ◽  
Vol 20 (7) ◽  
Author(s):  
C. F. BERNASCONI ◽  
R. B. JUN. KILLION
Keyword(s):  
Rate Constant ◽  
Nucleophilic Addition ◽  
Intrinsic Rate ◽  
Intrinsic Rate Constant

scholarly journals A Two-part Approach to the Determination of Intrinsic Rate Constants of an Alpha-amylase Catalysed Reaction

2020 ◽  
pp. 8-21
Author(s):  
Ikechukwu I. Udema
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Catalytic Efficiency ◽  
Intrinsic Rate ◽  
Product Formation ◽  
Intermolecular Potential ◽  
Diffusion Controlled ◽  
Quantitative Results ◽  
Intrinsic Rate Constant

Background: There is a need for equations with which to calculate the intrinsic rate constants that can further characterise enzyme catalysed reactions despite what seems to be conventional differences in methodology in the literature. Methods: Theoretical, experimental (Bernfeld method), and computational methods. Objectives: 1) To derive an alternative intrinsic rate constant equations consistent with their dimension, 2) derive electrostatic intermolecular potential energy equation, (xe), 3) calculate the intrinsic rate constants for forward (k1) and reverse (k2) reactions, and 4) define the dependence or otherwise of kinetic constants on diffusion and deduce the catalytic efficiency. Results and Discussion: The ultimate quantitative results were ~ 64.69 ±  0.49 exp (+3)/ min (k2) (and kd (s) = ~ 60.66 exp (+3)/ min), ~ 1594.48 ± 11.99 exp (+3) exp (+3) L/mol.min (k1) (and ka (s) = ~1482.47 exp (+3) L/mol.min), ~ 58.00 ± 10.83 exp (+3) /min, the apparent rate constant for reverse reaction (kb), and ~ 75.83 ± 10.83 exp (+3) /min, the rate constant for product formation (k3). The catalytic efficiency was: 3.025 exp (+ 9) L / mol.     Conclusion: The relevant equations were derived. Based on the derived equations the intrinsic rate constants can be calculated. Since k3 is > kb, then k3 is diffusion controlled and it appears that the enzyme has reached kinetic perfection. The evaluation of rate constants either from the perspective of diffusion dependency or independency cannot be valid without Avogadro number.

Carbanion reactivity — σ-adduct formation and elimination in the reactions of the carbanion from bis(phenylsulfonyl)methane with 4-nitrobenzofurazan derivatives

2008 ◽  
Vol 86 (3) ◽  
pp. 225-229 ◽  
Author(s):  
Basim H.M. Asghar ◽  
Michael R Crampton ◽  
Chukwuemeka Isanbor
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Intrinsic Rate ◽  
Adduct Formation ◽  
Nmr Studies ◽  
H Nmr ◽  
A Value ◽  
Elimination Reactions ◽  
Intrinsic Rate Constant

1H NMR studies in [2H6]-DMSO show that the carbanion 4 from bis(phenylsulfonyl)methane reacts with 4,6-dinitrobenzofuroxan to yield a σ-adduct that undergoes base-catalysed elimination to yield an alkene derivative. Rate constants, measured spectrophotometrically, are reported for the corresponding reactions in methanol of 4 with 4-nitrobenzofurazan and some derivatives that give adducts at the 5-position. The intrinsic rate constant, ko, for this process has a value of 1.5 ± 0.5. The 5-adducts undergo methoxide-catalysed elimination of phenylsulfinic acid to yield alkene derivatives and rate constants for this process are reported.Key words: carbanions, 4-nitrobenzofurazan, σ-adducts, elimination reactions.

Corrigendum to “The dissolution rates of simulated UK Magnox – ThORP blend nuclear waste glass as a function of pH, temperature and waste loading” [Miner. Mag. 79, (2015) 1529–1542]

2018 ◽  
Vol 82 (4) ◽  
pp. 939-942 ◽  
Author(s):  
Claire. L. Corkhill ◽  
Adam J. Fisher ◽  
Denis M. Strachan ◽  
Russell J. Hand ◽  
Neil C. Hyatt
Keyword(s):  
Nuclear Waste ◽  
Intrinsic Rate ◽  
Data Fitting ◽  
Waste Glass ◽  
Dissolution Rates ◽  
Nuclear Waste Glass ◽  
Corrected Data ◽  
Waste Loading ◽  
Fitting In ◽  
Intrinsic Rate Constant

AbstractWe revise the data fitting in our original paper [The dissolution rates of simulated UK Magnox - ThORP blend nuclear waste glass as a function of pH, temperature and waste loading, Miner. Mag.79 (2015) 1529–1542]. The intrinsic rate constant data were calculated incorrectly, the corrected data are presented herein. To support the corrected analysis we have also taken the opportunity to report some additional 90°C data. The conclusions of the original paper remain sound.

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