scholarly journals The Optimum Reaction Time, Activation Energy and Frequency Factor of Methyl Ricinoleate Nitration

2013 ◽  
Vol 13 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Abdullah Abdullah ◽  
Triyono Triyono ◽  
Wega Trisunaryanti ◽  
Winarto Haryadi
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Methyl Ricinoleate ◽  
Frequency Factor ◽  
Optimum Reaction

Determination of the optimum reaction time, activation energy (Ea) and frequency factor (A) of methyl ricinoleate nitration has been done. The nitration was conducted with the mole ratio of methyl ricinoleate to HNO3 of 1:15. The reaction was conducted at temperatures of 29 and 64 °C with a variation of reaction time for 10, 20, 30, 60, 90, 120, and 150 min. Determination of activation energy and frequency factor was performed in a temperature of 29, 33, 38, 44, 49, 57 and 64 °C. The results showed that the optimum reaction time is 90 min. The activation energy (Ea) and frequency factor (A) was 44.5 kJ/mol and 4.780 x 103 sec-1, respectively.

The Kinetics of Oxygen Delignification of Reed Kraft Pulp (I)-Kinetics of Delignification

2011 ◽  
Vol 236-238 ◽  
pp. 1420-1424
Author(s):  
Xiao Feng Pan ◽  
Le Fan Ma ◽  
Qin Qin Qu ◽  
Jia Liang Lan ◽  
Li Hong Tan
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Oxygen Pressure ◽  
Kraft Pulp ◽  
Reaction Order ◽  
Frequency Factor ◽  
Kappa Number ◽  
Alkali Concentration ◽  
Oxygen Delignification ◽  
Kinetics Of

The kinetics of reed kraft pulp oxygen delignification process is studied, suitable kinetics model determined is -dk/dt=Aexp(-E/RT) [OH-]b[PO2]cKa, and the parameters in the model is calculated. The function for estimation of the kappa number at different reaction time is established for the reed kraft pulp oxygen delignification process. The reaction order fitted is 6.72 for delignification (a), 0.87 for alkali concentration (b), and 0.62 for oxygen pressure(c), respectively. The activation energy E is 80.96KJ/mol and frequency factor A 1.5×104.

scholarly journals Thermal Degradation Studies of Terpolymer Derived from 2-Aminothiophenol, Hexamethylenediamine, and Formaldehyde

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
P. U. Belsare ◽  
A. B. Zade ◽  
P. P. Kalbende ◽  
M. S. Dhore
Keyword(s):  
Activation Energy ◽  
Average Molecular Weight ◽  
Conductometric Titration ◽  
Frequency Factor ◽  
Characteristic Functions ◽  
Spectral Techniques ◽  
H Nmr ◽  
Ft Ir ◽  
Relative Thermal Stability

Terpolymer (2-ATPHMDAF-I) has been synthesized by the condensation of 2-aminothiophenol and hexamethylenediamine with formaldehyde in the presence of 2 M hydrochloric acid as a catalyst with 1 : 1 : 2 molar proportion of reacting monomers. The structure of newly synthesized terpolymer has been elucidated and confirmed on the basis of elemental analysis and various spectral techniques, that is, UV-visible, FT-IR, and 1H-NMR spectroscopy. Number average molecular weight (Mn¯) has been determined by conductometric titration in nonaqueous medium. The viscosity measurements in dimethyl sulfoxide (DMSO) have been carried out to ascertain the characteristic functions and constants. The studies have been further extended to nonisothermal thermogravimetric analysis for determination of their mode of decomposition and relative thermal stability. Activation energy Ea, order of reaction (n), and frequency factor (z) were calculated by Friedman, Chang, Sharp-Wentworth and Freeman-Carroll methods. Activation energy calculated by Friedman and Chang methods are in close agreement with each other while the results obtained from Freeman-Carroll and Sharp-Wentworth’s methods are found to be in a similar order.

scholarly journals STUDY OF COLLOIDAL CHITIN HYDROLYSIS TO PRODUCE THE N ACETYL GLUCOSAMINE FROM SHRIMP SHELL WASTE USING HYDROCHLORIC ACID AND NITRIC ACID

2015 ◽  
Vol 2 (1) ◽  
pp. 77
Author(s):  
Sri Wahyuni
Keyword(s):  
Nitric Acid ◽  
Reaction Time ◽  
Hydrochloric Acid ◽  
Acid Hydrolysis ◽  
Optimum Concentration ◽  
Colloidal Chitin ◽  
Optimum Temperature ◽  
Chitin Hydrolysis ◽  
Optimum Reaction

Shrimp processing industries produces shrimp waste by 30-75% is wasted without being processed causing environmental pollution. The purpose of this study examines efforts to produce monomers of chitin hydrolysis of colloidal chitin compound derived from shrimp shells are chemically (hydrochloric acid and nitric acid) to produce N acetyl glucosamine bioactive compounds that have health benefits. The method used in this study is the optimization of chemical hydrolysis conditions using a solution of HCl and HNO3. On determining the optimum time to sample variation colloidal chitin 0,5%, 1% and 2%, the sample is heated with time variation 1,3,6, 9,12, and 24 hours at a temperature of 60 oC and the concentration of acid was 4 M. In the determination of the optimum temperature, each sample was heated at a temperature variation of 40, 60, and 80 oC at the optimum time (9 hours ) and acid concentration of 4 M. In the determination of the optimum concentration of acid, each sample was heated at a temperature and the optimum reaction time. Production results showed the highest compound N acetyl glucosamine as 623.3 ppm, using hydrochloric acid hydrolysis reaches optimum temperature 40° C, the optimum reaction time 9 hours, the optimum concentration of 4 M hydrochloric acid, the concentration of 2% colloidal chitin. Production of N acetyl glucosamine supreme as 625.83 ppm, using nitric acid hydrolysis reaches optimum temperature 60° C, the optimum reaction time 9 hours, the optimum concentration of 4M nitric acid, and the concentration of 1% colloidal chitin. Therefore we can conclude the results of 1% colloidal chitin hydrolysis using nitric acid more efficiently produce N acetyl glucosamine than hydrochloric acid, due to the temperature, reaction time, and acid concentration are not the same ability to hydrolyze colloidal chitin. Differences in the results of hydrolysis reached 11,59 ppm. Keywords : Chitin, N acetyl glucosamine, acid hydrolysis, optimum reaction 

scholarly journals Approaches to Biomass Kinetic Modelling: Thermochemical Biomass Conversion Processes

2021 ◽  
Vol 4 (Vol4) ◽  
pp. 1-13
Author(s):  
Omar Al-Ayed
Keyword(s):  
Activation Energy ◽  
Kinetic Models ◽  
Design Procedure ◽  
Network Models ◽  
Frequency Factor ◽  
Biomass Pyrolysis ◽  
Kinetic Triplet ◽  
One Step ◽  
The One

Modeling of biomass pyrolysis kinetics is an essential step towards reactors design for energy production. Determination of the activation energy, frequency factor, and order of the reaction is necessary for the design procedure. Coats and Redfern's work using the TGA data to estimate these parameters was the cornerstone for modeling. There are two significant problems with biomass modeling, the first is the determination of the kinetic triplet (Activation energy, Frequency factor, and the order of reaction), and the second is the quantitative analysis of products distribution. Methods used in modeling are either One-step or Multistep methods. The one-step techniques allow the determination of kinetic triplet but fail to predict the product distribution, whereas multistep processes indicate the product's distribution but challenging to estimate the parameters. Kissinger, Coats, and Redfern, KAS, FWO, Friedman are one-step methods that have been used to estimate the kinetic parameters. In this work, after testing more than 500 data points accessed from different literature sources for coal, oil shale, solid materials, and biomass pyrolysis using one-step global method, it was found that the activation energy generated by KAS or FWO methods are related as in the following equations: 𝐸𝐾𝐴𝑆 = 0.9629 ∗ 𝐸𝐹𝑊𝑂 + 8.85, with R² =0.9945 or 𝐸𝐹𝑊𝑂 = 1.0328 ∗ 𝐸𝐾𝐴𝑆 − 8.0969 with R2= 0.9945. The multistep kinetic models employed the Distributed Activation Energy Model (DAEM) using Gaussian distribution, which suffers from symmetry, other distributions such as Weibull, and logistic has been used. These multistep kinetic models account for parallel/series and complex, primary and secondary biomass reactions by force-fitting the activation energy values. The frequency factor is assumed constant for the whole range of activation energy. Network models have been used to account for heat and mass transfer (diffusional effects), where the one-step and multistep could not account for these limitations. Three network models are available, the Bio-CPD (Chemical Percolation Devolatilization) model, Bio-FLASHCHAIN, and the Bio-FGDVC (Functional Group Depolymerization Vaporization Crosslinking models). These models tried to predict the product distributions of the biomass pyrolysis process

scholarly journals Approximations to the Non-Isothermal Distributed Activation Energy Model for Biomass Pyrolysis Using the Rayleigh Distribution

2017 ◽  
Vol 20 (3) ◽  
pp. 78-84 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh
Keyword(s):  
Activation Energy ◽  
Numerical Solutions ◽  
Frequency Factor ◽  
Rayleigh Distribution ◽  
Energy Model ◽  
Biomass Pyrolysis ◽  
Distributed Activation Energy Model ◽  
Scale Parameters ◽  
Thermoanalytical Data

AbstractThis paper deals with the influence of some parameters relevant to biomass pyrolysis on the numerical solutions of the nonisothermalnthorder distributed activation energy model using the Rayleigh distribution. Investigated parameters are the integral upper limit, the frequency factor, the heating rate, the reaction order and the scale parameters of the Rayleigh distribution. The influence of these parameters has been considered for the determination of the kinetic parameters of the non-isothermalnthorder Rayleigh distribution from the experimentally derived thermoanalytical data of biomass pyrolysis.

Biosynthesis of Silver Nanoparticles Made from Green Tea Leaf Extract (Camellia sinensis)

2019 ◽  
Vol 967 ◽  
pp. 161-167
Author(s):  
Hasri ◽  
Iwan Dini ◽  
Satria Putra Jaya Negara ◽  
Subaer
Keyword(s):  
Silver Nanoparticles ◽  
Reaction Time ◽  
Green Tea ◽  
Leaf Extract ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Green Tea Leaves ◽  
Optimum Reaction ◽  
Tea Leaf

Silver nanoparticles act as anti-bacterial and anti-inflammatory. On the other hand, some plants contain reducing agents. Therefore, it is deemed necessary to know the potentiality of plant extracts such as green tea leaf extract on the synthesis of silver nanoparticles. The Methanol extract of green tea leaves serves as a reduction of AgNO3 solution. Determination of the optimum reaction time in forming nanosize using UV-Vis spectrophotometer every 30 minutes. Characterization of nanoparticles obtained using scanning electron microscopy (SEM) and particle size analyzer (PSA). The results showed that green tea leaf extract was able to reduce Ag + to silver nanoparticles at a reaction time of 90 minutes, the temperature of 70°C. Morphology is not uniform, tends to aggregate, and the size distribution of silver nanoparticles is 82.33-740.89 nm with an average diameter of 157.8 nm.

On temperature-dependent frequency factor in thermoluminescence measured with a hyperbolic heating profile

2001 ◽  
Vol 79 (9) ◽  
pp. 1133-1139 ◽  
Author(s):  
W S Singh ◽  
M Bhattacharya ◽  
S D Singh ◽  
P S Mazumdar
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Frequency Factor ◽  
Temperature Dependent ◽  
Order Of Kinetics ◽  
Dependent Frequency ◽  
Symmetry Factor ◽  
Heating Profile

In this paper, we investigate the consequences of the temperature dependence of the frequency factor on thermoluminescence peaks recorded in a hyperbolic heating profile. The temperature dependence of the frequency factor leads to nonuniqueness in the symmetry factor for a particular order of kinetics (b) and causes an error of the order of 5% in the determination of b and an error of the order of 10% in the determination of activation energy (E). PACS No.: 78.60Kn

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