Kinetics of Reactive Extraction of Pyruvic Acid Using Tributylamine Dissolved in n-Butyl Acetate

2015 ◽  
Vol 13 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Dharm Pal ◽  
Amit Keshav

Abstract Studies have been made on the kinetics accompanied with mass transfer for the pyruvic acid/tributylamine (TBA)/n-butyl acetate system to investigate the effectiveness of reactive extraction for the separation of pyruvic acid from the aqueous solution. In the present work, kinetic studies, needed for the design of a recovery unit, were carried out using aqueous solution of pyruvic acid. TBA (conc. range 0.420–2.099 kmol/m3) dissolved in n-butyl acetate (conc. range 50–90%) was used as an extractant. The effect of reactant concentration, the effect of stirring speed and the effect of phase volume ratio on the extraction process were investigated. The kinetic parameters such as reaction order and rate constant were calculated. Kinetic measurements showed that the reaction is of second order occurring in the diffusion film and was found to be independent of hydrodynamic conditions. Rate constant was evaluated to be $0.419\,{{\rm{m}}^3}{\rm{mo}}{{\rm{l}}^{- 1}}{{\rm{S}}^{- 1}}$ .

2012 ◽  
Vol 57 (4) ◽  
pp. 1011-1020 ◽  
Author(s):  
K. Pacławski ◽  
M. SIKORA

In this work the potential application of synchrotron radiation in the studies of reaction kinetics in aqueous phase were presented. After short introduction describing principles of technique and potential application of XAFS for the structural studies of reacting species, the experimental results of kinetic measurements of reaction between gold(III) chloride complex ions and ethanol were presented. Analyzing the changes of absorption intensity in the XANES spectra registered at Au-L3 edge during the reaction, the change of the valence state of Au central atom (form 3+to 0) of reacting complex ion was determined. Moreover, empirical XANES data gave the chance to register the kinetic curve and to determine the rate constant of the studied reaction. It was found that reaction is relatively slow (second-order rate constant k = 3.66 · 10-5 M-1s) and lead to the gold metallic phase formation in the system. Applying the continuous-flow method, within the first 600 ms of reaction the changes in XANES spectra were registered. From the obtained results, supported with numerical calculations, two intermediate forms of adducts appearing prior the electron transfer were suggested. It was concluded that when the classic methods, e.g. UV-Vis spectrophotometry, cannot be applied to studies of kinetics of reactions in aqueous solution, the XAFS technique can be a valuable and substitutive (or supplementary) tool for such measurements.


2010 ◽  
Vol 2 (2) ◽  
pp. 107-112
Author(s):  
Nuryono Nuryono ◽  
Narsito Narsito

In this research, treatment of diatomaceous earth, Sangiran, Central Java using hydrogen chloride (HCl) and sulfuric acid (H2SO4) on kinetics of Cd(II) adsorption in aqueous solution has been carried out. The work was conducted by mixing an amount of grounded diatomaceous earth (200 mesh in size) with HCl or H2SO4 solution in various concentrations for two hours at temperature range of 100 - 150oC. The mixture was then filtered and washed with water until the filtrate pH is approximately 7 and then the residue was dried for four hours at a temperature of 70oC. The product was used as an adsorbent to adsorb Cd(II) in aqueous solution with various concentrations. The Cd(II) adsorbed was determined by analyzing the rest of Cd(II) in the solution using atomic absorption spectrophotometry. The effect of treatment was evaluated from kinetic parameter of adsorption rate constant calculated based on the simple kinetic model. Results showed  that before equilibrium condition reached, adsorpstion of Cd(II) occurred through two steps, i.e. a step tends to follow a reaction of irreversible first order  (step I) followed by reaction of reversible first order (step II). Treatment with acids, either hydrogen chloride or sulfuric acid, decreased adsorption rate constant for the step I from 15.2/min to a range of 6.4 - 9.4/min.  However, increasing concentration of acid (in a range of concentration investigated) did not give significant and constant change of adsorption rate constant. For step II process,  adsorption involved physical interaction with the sufficient low adsorption energy (in a range of 311.3 - 1001 J/mol).     Keywords: adsorption, cdmium, diatomaceous earth, kinetics.


1986 ◽  
Vol 64 (6) ◽  
pp. 1267-1272 ◽  
Author(s):  
Oswald S. Tee ◽  
Jana Pika ◽  
M. Judith Kornblatt ◽  
Michael Trani

The kinetics of bromination of the title compound (1) have been measured in aqueous solutions of pH 0–6. The change in the order of reaction which occurs around pH 2.5 is explained by 1 reacting via its covalent hydrate, 3. Furthermore, there is sufficient 3 present at equilibrium that the kinetics of its equilibration with 1 were also measured. From these two studies the extent of covalent hydration of 1 is estimated to be 5%.Kinetic studies of the bromination of the dimethyl cation 5 and of its equilibration with the pseudobase 6 were also carried out for the purposes of comparison.The present results for 1, 3, 5, and 6 are compared to earlier results for 2-pyrimidinone and analogous derivatives.


2016 ◽  
Vol 15 (2) ◽  
pp. 62 ◽  
Author(s):  
Heri Septya Kusuma ◽  
Mahfud Mahfud

Sandalwood and its oil, is one of the oldest known perfume materials and has a long history (more than 4000 years) of use as mentioned in Sanskrit manuscripts. Sandalwood oil plays an important role as an export commodity in many countries and its widely used in the food, perfumery and pharmaceuticals industries. The aim of this study is to know and verify the kinetics and mechanism of microwave-assisted hydrodistillation of sandalwood based on a second-order model. In this study, microwave-assisted hydrodistillation is used to extract essential oils from sandalwood. The extraction was carried out in ten extraction cycles of 15 min to 2.5 hours. The initial extraction rate, the extraction capacity and the second-order extraction rate constant were calculated using the model. Kinetics of oil extraction from sandalwood by microwave-assisted hydrodistillation proved that the extraction process was based on the second-order extraction model as the experimentally done in three different steps. The initial extraction rate, h, was 0.0232 g L-1 min-1, the extraction capacity, CS, was 0.6015 g L-1, the second-order extraction rate constant, k, was 0.0642 L g-1 min-1 and coefficient of determination, R2, was 0.9597.


1986 ◽  
Vol 73 ◽  
Author(s):  
Carol A. Balfe ◽  
Kenneth J. Ward ◽  
David R. Tallant ◽  
Sheryl L. Martinez

ABSTRACTThe kinetics of hydrolysis of hexamethylcyclotrisiloxane and di-t-butyldimesitylcyclodisiloxane in tetrahydrofuran solution have been determined and compared to hydrolysis rates of silica defects. In the presence of sufficient excess witer, the first-order rate constant of the cyclotrisiloxine, k= 3.8 × 10−3 min is similar to the rate constant, k = 5.2 × 10−1 min, of the disappearance of the D2 Raman silica defect band it has been proposed to model. Limited hydrolysis rate data for the cyclodisiloxane suggests that it hydrolyzes at least four times faster than does the cyclotrisiloxane. These data are consistent with rate data available for silica crack growth and support the assignment of highly strained siloxane bonds at the crack tip to cyclodisiloxanes. Infrared spectra determined for the cyclodisiloxanes lend further support to this model.


2002 ◽  
Vol 56 (9) ◽  
pp. 381-385
Author(s):  
Ljubica Pavlovic ◽  
Zagorka Acimovic-Pavlovic ◽  
Ljubisa Andric ◽  
Aurel Prstic

In order to study the kinetics and mechanism of the reaction, laboratory leaching was carried out with industrially produced gibbsite ?-Al(OH)3 in aqueous solutions containing an excess of sodium hydroxide. The results obtained reaction temperature, duration and base concentration varied. The basic kinetic parameters were determined from: the reaction rate constant k=8.72?107 exp (-74990/RT) and the process activation energy in the range Ea=72.5-96.81 kJ/mol.


2011 ◽  
Vol 50 (23) ◽  
pp. 13518-13525 ◽  
Author(s):  
Mustafa E. Marti ◽  
Turker Gurkan ◽  
L. K. Doraiswamy

1984 ◽  
Vol 62 (9) ◽  
pp. 1681-1686 ◽  
Author(s):  
Robert Ménard ◽  
Miklos Zador

The complex formed between acridine orange (AO) and polycytidylic acid (poly(C)) was studied by spectrophotometry and spectrofluorometry. The complex was characterized by its stoichiometry, structure, and the thermodynamic parameters of its formation. The results are in agreement with an external aggregation of the protonated dye along the negatively charged poly(C) chain and indicate that approximately two AO molecules are bound per nucleotide unit of poly(C). The kinetics of the reaction between this complex and a Pd(II) complex was studied by the stopped-flow method. The addition of (dien)Pd(II) to the AO–poly(C) complex leads to the dissociation of the latter, due to fixation of the Pd(II) complex to the N3 site of the cytosine base of poly(C). The rate constant for the AO liberation, extrapolated at zero AO concentration, corresponds to the rate constant of Pd(II) fixation on poly(C). This indicates that AO can be used as an indicator for this reaction and allows kinetic studies at very low concentrations (≤ 5 × 10−6 M).


1970 ◽  
Vol 48 (13) ◽  
pp. 2035-2041 ◽  
Author(s):  
R. H. Betts ◽  
R. H. Voss

Oxygen of mass 18 was used as a stable tracer to measure the rate of exchange between the sulfite ion and water as a function of pH and total sulfite concentration. A value for the rate constant of hydration of SO2 in aqueous solution was determined. The gross rate constants k1 and k−1 for the overall reaction[Formula: see text]at 24.7 °C and ionic strength = 0.9 were evaluated from exchange results to be [Formula: see text]Also, for the first time, rate constants for the pyrosulfite equilibrium[Formula: see text]Were obtained[Formula: see text]at 24.7 °C and ionic strength = 0.9


2020 ◽  
Vol 10 (7) ◽  
pp. 676
Author(s):  
Huu Son Ta ◽  
Khu Le Van ◽  
Thu Thuy Luong Thi ◽  
Thanh Hoa Ha

The kinetics of phenol adsorption from aqueous solution on activated carbons (ACs) obtained from coffee husk by potassium Hydroxide (KOH) activation at 650 and 750<sup>o</sup>C have been studied in the range of     100-250 mg L<sup>-1</sup> initial phenol concentrations and at the temperatures range of 10 – 40<sup>o</sup>C. Kinetic models for phenol adsorption were evaluated using pseudo-first-order, pseudo-second-order, and Elovich models. The adsorption mechanism was investigated using Reichenberg, Boyd, and Weber and Morris models. The adsorption on coffee husk activated carbon was found to be a fast or speedy process with the adsorption rate, k<sub>2</sub>q<sub>e</sub>, in the range of 0.130 to 0.977 min<sup>-1</sup>. The adsorption process was mainly physical and promoted by chemical sorption and controlled not only by intra-particle diffusion but also by pore diffusion throughout the entire adsorption period.


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