In Situ Rapid Dechlorination by Microwave-Assisted Catalytic Reduction of Chlorobenzene and 1,4-Dichlorobenzene on Raney Ni-Al Alloy Catalyst

2019 ◽  
Vol 950 ◽  
pp. 110-116
Author(s):  
Bao Ying Lu ◽  
Xu He Hou
Keyword(s):  
Activation Energy ◽  
Reductive Dechlorination ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Al Alloy ◽  
Microwave Assisted ◽  
Raney Ni ◽  
Dechlorination Reaction ◽  
Alloy Catalyst

Microwave-assisted catalytic reductive dechlorination on Raney Ni-Al alloy catalyst is an efficient method for treatment of chlorobenzene (CB) and 1,4-dichlorobenzene (1,4-DCB). The result shows that the Raney Ni-Al alloy catalyst retains its high activity in this in-situ reductive dechlorination reaction. The reductive dechlorination reaction was in accordance of a psendo-second-order reaction kinetics under the microwave irradiation. The apparent reductive reaction rate constant of CB dechlorination was 0.0175 L/mol·min at 30°C and 0.114 L/ mol·min at 50°C, and the activation energy Ea was 76.24 kJ/mol. The reaction rate constant of 1,4-DCB dechlorination was 0.0376 L/ mol·min at 35 °C and 0.151 L/ mol·min at 50 °C, and the activation energy Ea was 76.66 kJ/mol. The dechlorination for CB and 1,4-DCB was rapid and complete under mild conditions. It shows that the microwave-assisted catalytic in-situ reductive dechlorination on Raney Ni-Al alloy catalyst is an effective method for dechlorination of polychlorinated organic compounds.

scholarly journals REDUCTIVE DECHLORINATION REACTION OF CHLORINATED ALIPHATICS BY ZERO-VALENT IRONS AND ITS DURABILITY OF REACTION RATE

2006 ◽  
Vol 62 (2) ◽  
pp. 268-277
Author(s):  
Masanori NEGISHI ◽  
Masanori SHIMOMURA ◽  
Yuichi HIGUCHI ◽  
Masaki TAKAOKA ◽  
Nobuo TAKEDA
Keyword(s):  
Reductive Dechlorination ◽  
Reaction Rate ◽  
Chlorinated Aliphatics ◽  
Dechlorination Reaction

Kinetic Studies on the Synthesis of Hydroxyapatite Nanowires by Solvothermal Methods

2007 ◽  
Vol 60 (2) ◽  
pp. 99 ◽  
Author(s):  
Shiying Zhang ◽  
Chen Lai ◽  
Kun Wei ◽  
Yingjun Wang
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Kinetic Studies ◽  
Axial Ratio ◽  
Reaction Rate Constant ◽  
Rate Equations ◽  
Solvothermal Reaction ◽  
Growth Order ◽  
Constant Diffusion ◽  
Solvothermal Methods

Hydroxyapatite nanowires with a high axial ratio have been synthesized in reverse micelle solutions that consist of cetyltrimethylammonium bromide (CTAB), n-pentanol, cyclohexane, and the reactant solution by solvothermal methods. This paper focusses on the kinetic studies of the solvothermal reaction and the linear growth of hydroxyapatite nanowires. When the reaction was carried out at low temperatures (65°C), the experimental results showed that the reaction rate was of zero order since the whole reaction was diffusion controlled with constant diffusion coefficients. In the middle to high temperature range (130–200°C), the kinetics were characterized by second order reaction kinetics. Since the controlling factor was activation energy and the apparent activation energy was large, the reaction rate was more sensitive to the temperature. Therefore, the exponent of the reaction rate constant increased by two when the temperature was increased from 130 to 200°C. By calculating the yields of products and the specific surface areas at different times, the linear and overall growth rate equations of the hydroxyapatite nanowires could be obtained. The experimental effective growth order of the crystals was 11. The larger growth order indicated that the crystal could grow more effectively in one direction because of the induction of the surfactant in the experiment system.

scholarly journals Microwave-Assisted Transesterification of Kusum Oil: Parametric, Kinetic and Thermodynamic Studies

2020 ◽  
Vol 32 (11) ◽  
pp. 2893-2903
Author(s):  
SHEETAL N. NAYAK ◽  
MILAP G. NAYAK ◽  
CHANDRAKANT P. BHASIN
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Molar Ratio ◽  
Pseudo First Order Reaction ◽  
Time Intervals ◽  
First Order ◽  
Microwave Assisted ◽  
Lower Heat ◽  
Kinetic And Thermodynamic Studies

Microwave-assisted transesterification of non-edible oil to produce biodiesel is gaining attention due to lower heat loss as well as rapid conversion. In this study, esterified kusum oil as a feedstock was transesterified in the presence of Ba(OH)2. At 800 W microwave power and constant magnetic stirring the effect of important process parameters such as solvent methanol molar ratio, Ba(OH)2, temperature, and time on biodiesel yield were evaluated. The parametric study suggested that 9:1 M methanol, 65 ºC reaction temperature, 2.5 wt% Ba(OH)2 catalyst and 3.5 min of transesterification time gave close to 96% biodiesel yield. At the above conditions of methanol and catalyst, the reaction kinetics and thermodynamic study were performed using different time intervals. The microwave-assisted transesterification followed pseudo-first-order reaction rate with 34.57 kJ/mol K activation energy and 205664 min-1 frequency factor. The reduction in activation energy and increase in the frequency factor reveal the non-thermal effect associated with microwave heating. The thermodynamic properties evaluated using the Eyring equation suggests non-spontaneity and endothermic nature of transesterification.

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.

Determination of the reaction rate constant and activation energy for pressure-induced 2+2 cycloaddition of the C60 fullerene

2002 ◽  
Vol 44 (3) ◽  
pp. 557-559 ◽  
Author(s):  
V. A. Davydov ◽  
L. S. Kashevarova ◽  
A. V. Rakhmanina ◽  
V. M. Senyavin ◽  
N. N. Oleinikov ◽  
...  
Keyword(s):  
Activation Energy ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
C60 Fullerene

One-pot low-temperature synthesis of TiO2 nanowire/rGO composites with enhanced photocatalytic activity

RSC Advances ◽  
2016 ◽  
Vol 6 (96) ◽  
pp. 94092-94097 ◽  
Author(s):  
Huan Xing ◽  
Wei Wen ◽  
Jin-Ming Wu
Keyword(s):  
Photocatalytic Activity ◽  
Reaction Rate ◽  
Uv Light ◽  
Reaction Rate Constant ◽  
Light Illumination ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
One Pot ◽  
Tio2 Nanowire

In situ growth of TiO2 nanowires on graphene oxide was achieved at 80 °C in an open atmosphere. The optimized TiO2/rGO hybrid exhibited a reaction rate constant 5.5 times that of TiO2 nanowires towards photodegradations of rhodamine B in water under the UV light illumination.

scholarly journals Effect of Thermal Pretreatment on the Solubilization of Organic Matters in a Mixture of Primary and Waste Activated Sludge

2015 ◽  
Vol 10 (2) ◽  
Keyword(s):  
Activation Energy ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Rate Constant ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Waste Activated Sludge ◽  
Pre Treatment ◽  
Reaction Activation Energy

The increased demand for advanced techniques in anaerobic digestion over the last few years has led to the employment of various pre-treatment methods prior to anaerobic digestion to increase gas production. These pre-treatment methods alter the physical and chemical properties of sludge in order to make it more readily degradable by anaerobic digestion. Although the thermal pre-treatment presents high energy consumption, the main part of this energy to heat can be recovered from the biogas produced in the anaerobic process. In this research a mixture of primary and waste activated sludge was thermally pretreated at 100, 125, 150, 175 and 200 oC in order to determine the reaction kinetics for the increase of soluble organic fraction (expressed as CODs and VFAs). Experimental results proved that the solubilization of sludge is a 1st order reaction with respect to both CODs and VFAs, KCODs (reaction rate constant of CODs solubilization) increased from 4.59*10-3 (min-1) to 7.55*10-3 (min-1) as the temperature increased from 100 to 200 oC, with a reaction activation energy of 7447.21 (J/mole) and frequency factor of 0.051 (min-1), While KVFAs (reaction rate constant of VFAs solubilization) increased from 5.33*10-3 (min-1) to 7.97*10-3 (min-1) for the same increase in temperature, with a reaction activation energy of 5947.22 (J/mole) and frequency factor of 0.0364 (min-1).

Modeling of the Formation Process of the Coherent Intermetallides in Nickel Alloys during Laser Treatment

2019 ◽  
Vol 822 ◽  
pp. 438-444 ◽  
Author(s):  
Andrey V. Alekseev ◽  
Ekaterina A. Valdaitseva ◽  
Vladimir L. Aleksandrov
Keyword(s):  
Laser Treatment ◽  
Reaction Rate ◽  
Treatment Process ◽  
Reaction Rate Constant ◽  
Process Time ◽  
Al Alloy ◽  
Chemical Reaction Rate Constant ◽  
Intermetallic Inclusion ◽  
Laser Cladding Process ◽  
New Phase

A solution for new phase inclusion growth is suggested for the case of the Ni-based alloys. This solution takes into account a chemical composition of the alloy and conditions of the laser treatment process. A method for calculation of the chemical reaction rate constant is also suggested for the Ni3Al formation in the Ni-Al alloy. Modeling is fulfilled for the laser cladding process. Time dependences for the reacting component concentration is obtained as well as for intermetallic inclusion growth and thermal cycle.

Wet And Dry Oxidation of Polycrystalline SixGe1-x Films

1998 ◽  
Vol 533 ◽  
Author(s):  
P.-E. Hellberg ◽  
S.-L. Zhang ◽  
F. M. d'Heurle ◽  
C. S. Petersson
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Quantitative Description ◽  
Reaction Rate Constant ◽  
Enhancement Effect ◽  
Wet Oxidation ◽  
Simultaneous Oxidation ◽  
Dry Oxidation ◽  
Different Temperatures ◽  
Si Films

AbstractWet and dry oxidations of polycrystalline SixGe1-x, with various compositions have been studied at different temperatures. The growth rate of SiO2 is found to be enhanced by Ge, and the enhancement effect is more pronounced in H2O than in O2. A mathematical model, which assumes simultaneous oxidation of Si and Ge and reduction of GeO2 by free Si available at the growing-oxide/SixGe1-x interface, is found to give a quantitative description of the SiO2 growth during thermal oxidation of SixGe1-x. Kinetic parameters are extracted by comparing the model with experiments. The linear and parabolic rate constants for Si oxidation are determined on control Si (100) wafers and polycrystalline Si films. Simple expressions are used for the interdiffusion of Si and Ge in SixGe1-x. For wet oxidation, the activation energy for the reaction rate constant of Ge oxidation is found to be smaller than that of Si oxidation.

scholarly journals Kinetics of gibbsite leaching in sodium hydroxide aqueous solution

2002 ◽  
Vol 56 (9) ◽  
pp. 381-385
Author(s):  
Ljubica Pavlovic ◽  
Zagorka Acimovic-Pavlovic ◽  
Ljubisa Andric ◽  
Aurel Prstic
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

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.

Sign in / Sign up

Export Citation Format

Share Document