THE REDUCTION OF CYTOCHROMEcBY HYDROQUINONE

1963 ◽  
Vol 41 (1) ◽  
pp. 231-237 ◽  
Author(s):  
G. R. Williams
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Rate Equation ◽  
Second Order ◽  
Order Rate ◽  
Ferricytochrome C ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Order Rate Equation

The kinetics of reduction of ferricytochrome c by hydroquinone have been studied. The reaction does not conform to a simple second-order rate equation and it is demonstrated that the deviations are brought about by the presence of p-quinone, one of the products of the reaction. The accelerating effect of p-quinone is explained tentatively on the basis of an involvement of the semi-quinone. The effects on the reaction of pH, ionic strength, and temperature are reported and used to suggest features of the reaction mechanism.

THE REDUCTION OF CYTOCHROMEcBY HYDROQUINONE

1963 ◽  
Vol 41 (1) ◽  
pp. 231-237 ◽  
Author(s):  
G. R. Williams
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Rate Equation ◽  
Second Order ◽  
Order Rate ◽  
Ferricytochrome C ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Order Rate Equation

The kinetics of reduction of ferricytochrome c by hydroquinone have been studied. The reaction does not conform to a simple second-order rate equation and it is demonstrated that the deviations are brought about by the presence of p-quinone, one of the products of the reaction. The accelerating effect of p-quinone is explained tentatively on the basis of an involvement of the semi-quinone. The effects on the reaction of pH, ionic strength, and temperature are reported and used to suggest features of the reaction mechanism.

Kinetics of the reduction of the tropylium and xanthylium cations by 1,4-dihydropyridine derivatives

1990 ◽  
Vol 68 (4) ◽  
pp. 537-542 ◽  
Author(s):  
John W. Bunting ◽  
M. Morgan Conn
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Ph Dependence ◽  
Second Order ◽  
Order Rate ◽  
Heteroaromatic Cation ◽  
Absolute Magnitudes ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Dihydropyridine Derivatives

The pH-dependences of the apparent second-order rate constants [Formula: see text] for the reduction of 2,4,6-cycloheptatrien-1-ol and 9-xanthydrol by each of 1-benzyl-1,4-dihydronicotinamide (BNH) and 10-methyl-9,10-dihydroacridine (MAH) have been measured in 20% acetonitrile – 80% water, at 25 °C and ionic strength 1.0. For each of these reactions, the pH-dependence of [Formula: see text] is only consistent with reduction occurring via the aromatic cation (either tropylium or xanthylium) that is present in equilibrium with these alcoholic species. The relative second-order rate constants [Formula: see text] for reductions by these two reducing agents (1700 for tropylium and 770 for xanthylium) are similar for these two cations. These ratios are also similar to those observed for a variety of nitrogen heteroaromatic hydride acceptors, even though the absolute magnitudes of these rate constants vary by 1010-fold. The second-order rate constants for the reductions of the tropylium and xanthylium cations are predicted reasonably well by their [Formula: see text] values, with the latter cation being (7 × 105)-fold more reactive than its π-isoelectronic N-methyl acridinium cation. The xanthylium cation has the greatest [Formula: see text] ratio yet observed for any heteroaromatic cation, and this value further extends the known range of this ratio as a function of reactivity. Keywords: hydride transfer, kinetics of reduction, 1,4-dihydropyridine derivatives, tropylium cation, xanthylium cation.

scholarly journals KINETICS OF GASEOUS TOLUENE ADSORPTION ON CANDLENUT SHELL ACTIVATED CARBON

2013 ◽  
Vol 13 (1) ◽  
pp. 33 ◽  
Author(s):  
Audy D Wuntu ◽  
Vanda S Kamu
Keyword(s):  
Activated Carbon ◽  
Rate Equation ◽  
Order Rate Constant ◽  
Second Order ◽  
Rate Equations ◽  
Order Rate ◽  
Pseudo Second Order ◽  
Gaseous Toluene ◽  
Kinetics Of ◽  
Order Rate Equation

KINETICS OF GASEOUS TOLUENE ADSORPTION ON CANDLENUT SHELL ACTIVATED CARBON ABSTRACT Adsorption kinetics of gaseous toluene on activated carbon prepared from candlenut shell had been studied. The research was performed by examining adsorption data, which was obtained in previous research, over several rate equations, which were: (1) Lagergren’s pseudo first order rate equation, (2) Ho’s pseudo second order rate equation, (3) Elovich’s equation, and (4) persamaan Ritchie’s equation. The result showed that the data of toluene adsorption on candlenut shell activated carbon fits the Ho’s pseudo second order rate equation and, hence, the model is the most applicable model for the adsorption. Calculation from linear regression of Ho’s pseudo second order rate equation gave the equilibrium adsorption capacity value of 56,069 mg g-1, second order rate constant of 3,54x10–4 g mg-1 min-1, and initial adsorption rate of 1,112 mg g-1 min-1. Keywords: adsorption, candlenut, activated carbon, toluene KINETIKA ADSORPSI GAS TOLUENA PADA KARON AKTIF TEMPURUNG KEMIRI ABSTRAK Studi mengenai aspek kinetika adsorpsi toluena pada arang aktif yang terbuat dari tempurung kemiri telah dilakukan. Penelitian dilakukan dengan menguji data adsorpsi yang telah diperoleh pada penelitian terdahulu menggunakan empat persamaan laju adsorpsi, yaitu (1) persamaan laju pseudo order pertama Lagergren, (2) persamaan laju pseudo order kedua Ho, (3) persamaan Elovich, dan (4) persamaan Ritchie. Hasil kajian menunjukkan bahwa model kinetika dengan persamaan laju pseudo order kedua Ho adalah yang paling sesuai diaplikasikan untuk adsorpsi gas toluena pada arang aktif tempurung kemiri. Dari persamaan linear untuk model kinetika pseudo order kedua Ho diperoleh nilai kapasitas adsorpsi pada kesetimbangan sebesar 56,069 mg g-1, konstanta adsorpsi sebesar 3,54x10–4 g mg-1 menit-1, dan laju adsorpsi awal sebesar 1,112 mg g-1 menit-1. Kata kunci: adsorpsi, kemiri, karbon aktif, toluena

KINETICS OF THE AQUEOUS ALKALINE HOMOGENOUS HYDROLYSIS OF HIGH EXPLOSIVE 1, 3,5,7-TETRAAZA- 1, 3,5,7-TETRANITROCYCLOOCTANE (HMX)

1994 ◽  
Vol 30 (3) ◽  
pp. 53-61 ◽  
Author(s):  
Harro M. Heilmann ◽  
Michael K. Stenstrom ◽  
Rolf P. X. Hesselmann ◽  
Udo Wiesmann
Keyword(s):  
Temperature Dependence ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Elevated Temperatures ◽  
Second Order ◽  
Order Rate ◽  
Subsequent Calculation ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Order Rate Equation

In order to get basic data for the design of a novel treatment scheme for high explosives we investigated the kinetics for the aqueous alkaline hydrolysis of 1,3,5,7-tetraaza-1,3,5,7-tetranitrocyclooctane (HMX) and the temperature dependence of the rate constants. We used an HPLC procedure for the analysis of HMX. All experimental data could be fit accurately to a pseudo first-order rate equation and subsequent calculation of second-order rate constants was also precise. Temperature dependence could be modeled with the Arrhenius equation. An increase of 10°C led to an average increase in the second-order rate constants by the 3.16 fold. The activation energy of the second-order reaction was determined to be 111.9 ±0.76 kJ·moJ‒1. We found the alkaline hydrolysis to be rapid (less than 2.5% of the initial HMX-concentration left after 100 minutes) at base concentrations of 23 mmol oH‒/L and elevated temperatures between 60 and 80°C.

Biosorption of Lignin Compounds Using Biomass Derived from Eichhornia crassipes: Batch Studies

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Renganathan Sahadevan ◽  
Ajit Balaji Kannavadi Devaraj ◽  
Dharmendira Kumar Mahendradas ◽  
Baskar Gurunathan ◽  
Manickam Velan
Keyword(s):  
Rate Equation ◽  
Eichhornia Crassipes ◽  
Second Order ◽  
Isotherm Model ◽  
Batch Studies ◽  
First Order ◽  
Order Rate ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Order Rate Equation

Biosorption of lignin compounds by the Eichhornia crassipes was investigated in batch studies. Batch experiments were conducted to study the effect of initial sorbent dosage, solution pH and lignin compounds concentration. Langmuir and Freundlich adsorption isotherm models were used to represent the equilibrium data. The Freundlich isotherm model was found to be fitted very well with the experimental data when compared to Langmuir isotherm model. The results showed that the equilibrium uptake capacity was found to be increased with decrease in biomass dosage. The lignin compound removal was influenced by the initial lignin compounds concentration. The sorption results were analysed for pseudo first order and pseudo second order kinetic model. It was observed that the kinetic data fitted very well with the pseudo second order rate equation when compared to the pseudo first order rate equation. Sorption results were analyzed for the intra particle diffusion model.

scholarly journals Kinetic Model for Lead(II) Sorption on to Peat

1998 ◽  
Vol 16 (4) ◽  
pp. 243-255 ◽  
Author(s):  
Y.S. Ho ◽  
G. McKay
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Kinetic Model ◽  
Second Order ◽  
Sorption Rate ◽  
Sorption Model ◽  
Order Rate ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Order Rate Equation

The kinetics of lead sorption on to peat have been investigated. The batch sorption model, based on the assumption of a pseudo-second order mechanism, has been developed to predict the rate constant of sorption, the equilibrium capacity and initial sorption rate with the effect of initial lead(II) concentration, peat particle size and temperature. An equilibrium capacity of sorption has been evaluated with the pseudo-second order rate equation. In addition, an activation energy of sorption has also been determined based on the pseudo-second order rate constants.

On the kinetics of cellulose degradation: looking beyond the pseudo zero order rate equation

Cellulose ◽  
2007 ◽  
Vol 15 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Paolo Calvini ◽  
Andrea Gorassini ◽  
Antonio Luigi Merlani
Keyword(s):  
Rate Equation ◽  
Cellulose Degradation ◽  
Zero Order ◽  
Order Rate ◽  
Kinetics Of ◽  
Order Rate Equation

The trans-Effect in Octahedral Complexes. VI. Base Hydrolysis of trans-Hydroxybromo and trans-Hydroxychlorobis(ethylenediamine)-rhodium(III) Complexes

1975 ◽  
Vol 53 (12) ◽  
pp. 1842-1848 ◽  
Author(s):  
Anthony Poë ◽  
Carol Vuik
Keyword(s):  
Rate Equation ◽  
Base Hydrolysis ◽  
Small Contribution ◽  
Trans Effect ◽  
First Order ◽  
Order Rate ◽  
Pseudo First Order ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Order Rate Equation

The kinetics of base hydrolysis of the complexes trans-[Rh(en)2(OH)X]+ (X = Br or Cl) follow the pseudo first order rate equation kobs = k1 + k2[OH−]. The small contribution of the [OH−]-dependent term is due to lower values of ΔS2≠ − ΔS1≠ than are observed for the complexes cis-[Rh(en)2(OH)Cl]+ and [Rh(NH3)5X]2+ (X = Cl, Br, or I ). The values of ΔH1≠ are used to obtain new values of the intrinsickinetictrans-effect (i.k.t.e.) of hydroxide that agree with that determined from aquation of trans.-[Rh(en)2(OH)I]+ and place hydroxide in the i.k.t.e. series [Formula: see text] The new data also allow hydroxide to be placed in a thermodynamic trans-effect (t.t.e.) series I > OH > NH3 > Br > Cl > OH2, and the different position of hydroxide in the two series is discussed.

Adsorption-Desorption Characteristics of E.coli by Quartz Sands of Different Particle Size

2014 ◽  
Vol 955-959 ◽  
pp. 436-444
Author(s):  
Zhi Rong Wang ◽  
Wei Li Wang ◽  
Xiao Yan Zhu ◽  
Jing Lan Wang ◽  
Zhi Jie Han ◽  
...  
Keyword(s):  
Particle Size ◽  
Rate Equation ◽  
Second Order ◽  
E Coli ◽  
Order Rate ◽  
Quartz Sands ◽  
Pseudo Second Order ◽  
Adsorption Desorption ◽  
Adsorption Quantity ◽  
Order Rate Equation

Adsorption-desorption characteristics of E. coli by quartz sands of five different particle size (351、319、217、71、27μm) were studied using batch equilibrium method. The results showed that quartz sands had great adsorption quantity of E. coli. The adsorption ratio could reach above 95%,when the initial microbial concentration was 109 cfu/mL. With the decreased of the quartz sand particle size,the adsorption quantity increased,and adsorption reached balance faster. The Pseudo-second-order rate equation is optimal to describe adsorption kinetics of E. coli by quartz sands, and the isothermal adsorption process is suitable to describe using Henry equation. Quartz sands had small desorption ratio of E. coli,the desorption ratio increased as quartz sands particle size increased, the largest desorption ratio was only 3.6%.The desorption dynamic processes and desorption isothermal processes also can be decreased using Pseudo-second-order rate equation and Henry equation respectively. Desorption of E. coli on quartz sands existed obvious hysteresis. It indicated there existed irreversible adsorption between E. coli and quartz sands, which the E. coli adsorbed was hard to desorb. The average particle size of quartz sands have some relevance with the parameters of Henry equation and Pseudo-second-order rate equation. This shows that particle size is one of the important factors that affect the adsorption and desorption.

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