scholarly journals Enzymatic Kinetics of Solvent-free Esterification with Bio-imprinted Lipase

2020 ◽  
Vol 33 (4) ◽  
pp. 495-499
Author(s):  
M. Matsumoto ◽  
Y. Hasegawa
Keyword(s):  
Carboxylic Acids ◽  
Propionic Acid ◽  
Catalytic Reaction ◽  
Reaction Rate ◽  
Isoamyl Alcohol ◽  
Reaction Rate Constant ◽  
Solvent Free ◽  
Enzymatic Esterification ◽  
Catalytic Activities ◽  
Kinetics Of

To avoid the use of compounds that burden the environment, a solvent-free enzymatic<br /> reaction was the focus of this study. Investigated were the catalytic activities and kinetics of lipases that were pretreated with carboxylic acids for the solvent-free esterification of propionic acid with isoamyl alcohol. The enhancements of the esterification yields and rates by the bio-imprinting effects of carboxylic acids were observed. We found no inhibition of isoamyl alcohol on the solvent-free enzymatic esterification, and obtained a large imprinting effect under a largely excessive amount of isoamyl alcohol to propionic acid. From the kinetic analysis, the imprinting of lipases mainly enhanced the catalytic reaction rate constant rather than the affinity between lipase and propionic acid compared with untreated lipase. The bio-imprinting treatment of lipase is found to be very effective for the yield and kinetics in solvent-free esterification.

Catalytic effects of high Fe(III) concentrations on Fe(II) oxidation

1996 ◽  
Vol 34 (7-8) ◽  
pp. 389-396 ◽  
Author(s):  
N. Tüfekci ◽  
H. Z. Sarikaya
Keyword(s):  
Catalytic Reaction ◽  
Ferrous Iron ◽  
Reaction Rate ◽  
Iron Oxidation ◽  
Quadratic Equation ◽  
Reaction Rate Constant ◽  
Batch Reactors ◽  
Ferrous Iron Oxidation ◽  
Kinetics Of ◽  
Catalytic Effects

Catalytic effect of the ferric hydroxides on the oxidation of ferrous iron by aeration has been demonstrated and the kinetics of this catalytic reaction has been formulated by the recent studies. It has been reported that the oxidation rate is linearly increasing with Fe(III) concentrations up to 100 mg/l. In this study, the oxidation of Fe(II) is studied in batch reactors in which the concentration of Fe(III) was in the range of 0-600 mg/l. A quadratic equation has been given to determine the catalytic reaction rate constant as a function of Fe(III) concentration. It was experimentally demonstrated that there was no significant effect of Fe(III) on the ferrous iron oxidation at Fe(III) concentrations beyond 600 mg/l.

Reduction Kinetics of Mill Scale Briquettes by Using A3 Fine Coal as a Reductant

2021 ◽  
Vol 21 (4) ◽  
pp. 2563-2567
Author(s):  
Nguyen Hoang Viet ◽  
Pham Ngoc Dieu Quynh ◽  
Nguyen Thi Hoang Oanh
Keyword(s):  
Reaction Rate ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Reaction Rate Constant ◽  
Reduction Degree ◽  
Furnace Temperature ◽  
Time Duration ◽  
Mill Scale ◽  
Fine Coal ◽  
Kinetics Of

In this work, a mixture of mill scale with 5 wt% molasses as binder was pressed under pressure of 200 MPa to prepare briquettes. The reduction process was performed at the temperature of 1000, 1050, 1100, 1150 and 1200 °C in the bed of A3 fine coal as the reductant. The degree of reduction was evaluated at time duration of 15, 30, 45, 60, 90 and 150 minutes, after the furnace temperature reached the predetermined reduction temperature. The highest reduction degree is 94.7% at the reduction process temperature of 1200 °C. Reaction rate constant (k) increased from 4.63×10-4 to 5.03×10-3 min-1 when the temperature increased from 1000 to 1200 °C. The apparent activation energy of the reduction reaction (Ea) is about 95.6 kJ/mole.

scholarly journals The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate

2000 ◽  
Vol 65 (12) ◽  
pp. 857-866
Author(s):  
Mladjen Micevic ◽  
Slobodan Petrovic
Keyword(s):  
Kinetic Data ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Activation Entropy ◽  
Second Order Reaction ◽  
Third Order ◽  
First Order ◽  
Kinetics Of

The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate (soman) was examined with a series of alkoxides and in corresponding alcohols: methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol and 2-ethoxyethanol. Soman reacts with the used alkoxides in a second order reaction, first order in each reactant. The kinetics of the reaction between 1,2,2-trimethylpropyl-methylfluorophosphonate and ethanol in the presence of diethylenetriamine was also examined. A third order reaction rate constant was calculated, first order in each reactant. The activation energy, frequency factor and activation entropy were determined on the basis of the kinetic data.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

scholarly journals Surface and Catalytic Properties of NiO–Fe2O3 Solids Supported on Al2O3

1996 ◽  
Vol 13 (5) ◽  
pp. 409-421 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
N.M. Deraz
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Properties ◽  
Unit Area ◽  
Surface Characteristics ◽  
Reaction Rate Constant ◽  
Oxidation Of Co ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Specific Surface Areas

A series of NiO–Fe2O3 catalysts supported on γ-Al2O3 was prepared. The effect of the NiO and Fe2O3 contents and the precalcination temperature on the surface and catalytic properties of the various solids has been investigated. The surface characteristics, viz. SBET, Vp and r, were determined using N2 adsorption conducted at –196°C. The catalytic activities of the various solids were studied using the oxidation of CO by O2 at temperatures in the range between 150°C and 400°C. The prepared solids were preheated in air at various temperatures between 400°C and 1000°C. The results obtained revealed that the SBET values of the different solids decrease progressively on increasing the precalcination temperature above 400°C due to sintering. The specific surface areas were also found to decrease on increasing both the NiO and Fe2O3 contents. The catalytic activities, expressed as reaction rate constant (k) and reaction rate constant per unit area (k), were found to decrease on increasing the precalcination temperature in the range 400–1000°C. Furthermore, the amounts of NiO and Fe2O3 in the different solids modified their catalytic activities in different manners.

scholarly journals Batch Kinetics of Nutrients Removal from Synthetic Meat Processing Wastewater by using Microalgae Botryococcus Sp.

2018 ◽  
Vol 7 (4.30) ◽  
pp. 553
Author(s):  
Vikneswara A. Shanmugan ◽  
Radin M.S.R. Mohammed ◽  
Amir H.B.M. Kassim ◽  
Adel A.S. Al-Gheethi ◽  
Nur A.A. Latiffi
Keyword(s):  
Reaction Rate ◽  
Ammonia Nitrogen ◽  
Reaction Rate Constant ◽  
Synthetic Wastewater ◽  
Nutrients Removal ◽  
Meat Processing ◽  
Chl A ◽  
Half Saturation Constant ◽  
Kinetics Of ◽  
High Range

Disposed meat processing wastewater contains high range of nutrients such as ammonia nitrogen and orthophosphate which will cause eutrophication and lead to destruction of ecosystem. Therefore, batch experiments were conducted to explore the influence of the range of initial concentration of ammonia nitrogen and orthophosphate found in meat processing wastewater in the removal of those nutrients during phycoremediation of synthetic wastewater by using microalgae Botryococcus sp. Michaelis-Menten rate expression was applied to generate biokinetic coefficients k, reaction rate constant, Km, half saturation constant and Y, yield coefficients. The experiment was conducted using synthetic wastewater with initial NH4-N concentration varying between 30-480 mg/l and PO43- concentrations varying between 14-239 mg/l. The results demonstrate removal efficiency of NH4-N between 42-100 % and PO43- between 63-96 %. Biokinetic coefficients were established as k = 1.72 mg NH4-N /mg chl a/day, Km = 52.29 mg/L and YN = 0.027 mg chl a/mg NH4-N for ammonia nitrogen and k = 1.13 mg PO43-/mg chl a/day, Km = 44.45 mg/L and YP = 0.038 mg chl a/mg PO43- for orthophosphate.  

scholarly journals Kinetics of Thermal Degradation of Recycled Polyvinyl Chloride Resin

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
I. M. Alwaan
Keyword(s):  
Thermal Degradation ◽  
Polyvinyl Chloride ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Rate Of Reaction ◽  
Different Temperatures ◽  
Zero Order Reaction ◽  
Enthalpy And Entropy ◽  
Kinetics Of ◽  
Entropy Of Reaction

The goal of this study is to find the effect of time and temperature on the thermal degradation of recycled polyvinyl chloride (PVC) resin. The isothermal rate of reaction(r)of recycled PVC resin was investigated at the following temperatures to: 100, 110, 120, 130, and 140°C at period of times ranging from 10 to 50 min. The result shows that the rate of reaction(r)of recycled PVC increases with increasing temperatures. The reaction rate constant(K)for temperatures ranging from 100 to 140°C was doubled from 0.028–0.056 mol·L−1·S−1. The process was found to be zero order reaction at all range of temperatures 100–140°C. The activation energy of the thermal weight loss was calculated at different temperatures(E/R = 2739.5°K). The average enthalpy and entropy of reaction at temperature of 298°K were determined.

Photocatalytic Degradation of Bisphenol AF in TiO2 Suspension

2014 ◽  
Vol 955-959 ◽  
pp. 2334-2339
Author(s):  
Pin Wen Wang
Keyword(s):  
Photocatalytic Degradation ◽  
Reaction Rate ◽  
Degradation Kinetics ◽  
Fluoride Concentration ◽  
Reaction Rate Constant ◽  
Rate Model ◽  
Initial Concentration ◽  
Fluoride Pollution ◽  
Kinetics Of ◽  
Bisphenol Af

The photodegradation behavior of bisphenol AF (BPAF) in TiO2 suspension was investigated. The influence of dissolved oxygen, TiO2 dosage, fluoride, and initial BPAF concentration on the degradation of BPAF was studied and described in details. The main purposes were to clarify the degradation kinetics of BPAF and quantify the fluoride concentration during the degradation. At an initial concentration of 40 mol/L, more than 97% of TOC was removed efficiency was achieved within 540 min irradiation, and the concentration of fluoride was 0.98 mg/L. Degradation of BPAF followed the Langmuir–Hinshelwood kinetics rate model and the reaction rate constant kre was 1.21 μM/min. The results obtained indicated that TiO2 photocatalytic degradation is a highly effective way to remove BPAF without any generation of more toxic products or fluoride pollution.

scholarly journals Reaction Kinetics of Carbon Dioxide in Aqueous Diethanolamine Solutions Using the Stopped-Flow Technique

2012 ◽  
Vol 19 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Marta Siemieniec ◽  
Hanna Kierzkowska-Pawlak ◽  
Andrzej Chacuk
Keyword(s):  
Carbon Dioxide ◽  
Reaction Kinetics ◽  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Stopped Flow ◽  
First Order ◽  
Pseudo First Order ◽  
Kinetics Of ◽  
Good Agreement

Reaction Kinetics of Carbon Dioxide in Aqueous Diethanolamine Solutions Using the Stopped-Flow Technique The pseudo-first-order rate constants (kOV) for the reactions between CO2 and diethanolamine have been studied using the stopped-flow technique in an aqueous solution at 293, 298, 303 and 313 K. The amine concentrations ranged from 167 to 500 mol·m-3. The overall reaction rate constant was found to increase with amine concentration and temperature. Both the zwitterion and termolecular mechanisms were applied to correlate the experimentally obtained rate constants. The values of SSE quality index showed a good agreement between the experimental data and the corresponding fit by the use of both mechanisms.

Crystallization Kinetics of CaOx in Artificial Urine and in Saline System

2014 ◽  
Vol 881-883 ◽  
pp. 708-711
Author(s):  
Lan Qing Deng ◽  
Jun Fa Xue ◽  
Li Kuan ◽  
Jian Ming Ouyang
Keyword(s):  
Reaction Time ◽  
Calcium Oxalate ◽  
Crystallization Kinetics ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Reaction Rate Constant ◽  
Artificial Urine ◽  
Kinetics Of

The crystallization kinetics of calcium oxalate (CaOx) was comparatively studied by detecting the change of free Ca2+ ions concentration with the reaction time in artificial urine and in saline system. The dynamics equations of CaOx crystallization was r=kcα, and the average reaction order (α) was 3.3 regardless of the relative suprasaturation degree (RS) of CaOx in the range of RS=10.58~17.53. The average reaction rate constant (κ) was (0.97±0.1)×109 in artificial urine and κ=(3.1±1.8)×109 in saline system, due to the presence of inhibitors to CaOx crystallization in artificial urine.

Sign in / Sign up

Export Citation Format

Share Document