Mathematical modeling of transesterification process kinetics of triglycerides catalyzed by TMAH

Biodiesel is a renewable fuel mainly produced by methylation of triglycerides of vegetable oils or animal fats. The production processes nowadays are particularly based on the utilization of inorganic alkali catalysts. However, it has been proved that an organic alkali – tetramethylammonium hydroxide (TMAH) – can also be used as a very efficient transesterification catalyst. The work presented herein is focused on mathematical modeling of the kinetics of TMAH-catalyzed transesterification of triglycerides at different reaction conditions, specifically at varying reaction temperature with the aim to understand the reaction mechanism and identify the key variables for optimization of the production process. The main kinetic parameters were calculated based on the mathematical- statistical processing of experimental kinetic data. The reaction rate constants for individual consecutive and reversible reactions and the corresponding activation energies were calculated.

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Current Issues in Sol-Gel Reaction Kinetics

MRS Proceedings ◽

10.1557/proc-180-21 ◽

1990 ◽

Vol 180 ◽

Cited By ~ 1

Author(s):

Roger A. Assink ◽

Bruce D. Kay

Keyword(s):

Reaction Kinetics ◽

Sol Gel ◽

Early Time ◽

Acid Catalyst ◽

Reaction Rates ◽

Reaction Conditions ◽

Reaction Rate Constants ◽

Condensation Reactions ◽

Experimental Findings ◽

Kinetics Of

ABSTRACTThis paper surveys a few of the current issues in sol-gel reaction kinetics. Many times seemingly modest changes in reactants or reaction conditions can lead to substantial differences in the overall reaction rates and pathways. For example, qualitative features of the reaction kinetics can depend on catalyst concentration. At very high acid-catalyst concentrations, reverse reactions are significant for TMOS solgels, while for moderate acid-catalyst concentrations, reverse reactions are substantially reduced. The reaction kinetics of two similar tetraalkoxysilanes: tetramethoxysilane (TMOS) and tetraethoxysilane (TEOS), can be markedly different under identical reaction conditions. Under acid-catalyzed reaction conditions, a TMOS sol-gel undergoes both water- and alcoholproducing condensation reactions while a TEOS sol-gel undergoes only water-producing condensation. The early time hydrolysis and condensation reactions of a TMOS sol-gel are statistical in nature and can be quantitatively described by a few simple reaction rate constants while the reaction behavior of a TEOS sol-gel is markedly nonstatistical. A comprehensive theory of sol-gel kinetics must address these diverse experimental findings.

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STUDYING THE KINETIC CHARACTERISTICS OF THE EXTRACTION OF ANTHOCYANINS FROM THE SQUEEZE OF KRASNOSTOP ZOLOTOVSKY

STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS. In the frame of the XXIII Agribusiness Forum of the South of Russia and the Exhibition «Interagromash» Volume 1 ◽

10.23947/interagro.2020.1.525-528 ◽

2020 ◽

Author(s):

M.A. Egyan ◽

Keyword(s):

Reaction Rate ◽

Sugar Content ◽

Extraction Process ◽

Efficiency Coefficient ◽

Kinetic Characteristics ◽

Reaction Rate Constants ◽

Solids Content ◽

Kinetics Of ◽

Process Speed

The article shows studies characterizing the quality of the squeeze: the mechanical composition of the squeeze is determined, the structural moisture of each component is determined, the sugar content in the formed process of sedimentation of the juice and its acidity are determined refractometrically. The kinetics of anthocyanins extraction was determined in two ways, the solids content in the extract was calculated, and the reaction rate constants of the extraction process and the efficiency coefficient of ultrasonic amplification of the extraction process speed were calculated.

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Effects of salts on the kinetics of oxidation of alkenes by thallic salts in aqueous solutions

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810693 ◽

1981 ◽

Vol 46 (3) ◽

pp. 693-700 ◽

Cited By ~ 1

Author(s):

Milan Strašák ◽

Jaroslav Majer

Keyword(s):

Aqueous Solutions ◽

Phase Transfer ◽

Heterogeneous Reaction ◽

Qualitative Model ◽

Kinetic Effect ◽

Tetraalkylammonium Salts ◽

Reaction Conditions ◽

Kinetics Of Oxidation ◽

Kinetics Of ◽

Heterogeneous Reaction Conditions

The kinetics of oxidation of alkenes by thallic sulphate in aqueous solutions, involving the two reaction steps-the hydroxythallation and the dethallation - was studied, and the effect of salts on the kinetics was examined; this made it possible to specify more precisely the reaction mechanism and to suggest a qualitative model of the reaction coordinate. It was found that in homogeneous as well as in heterogeneous reaction conditions, the reaction can be accelerated appreciably by adding tetraalkylammonium salts. These salts not only operate as catalysts of the phase transfer, but also exert a significant kinetic effect, which can be explained with a simplification in terms of a stabilization of the transition state of the reaction.

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A Novel Pseudomonas geniculata AGE Family Epimerase/Isomerase and Its Application in d-Mannose Synthesis

Foods ◽

10.3390/foods9121809 ◽

2020 ◽

Vol 9 (12) ◽

pp. 1809

Author(s):

Zhanzhi Liu ◽

Ying Li ◽

Jing Wu ◽

Sheng Chen

Keyword(s):

3D Structure ◽

Three Dimensional ◽

Optimal Temperature ◽

Reaction Conditions ◽

Enzymatic Production ◽

Physiological Properties ◽

Potential Applications ◽

Kinetics Of ◽

Optimal Reaction ◽

Gene Age

d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s−1, and 9.7 ± 0.5 s−1·mM−1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L−1 under optimal reaction conditions of 200 g·L−1d-fructose and 2.5 U·mL−1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.

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Effect of Reaction Conditions on the Kinetics of Living Isobutylene Polymerization at High Initiator/TiCl4Ratios

Macromolecules ◽

10.1021/ma992032g ◽

2000 ◽

Vol 33 (13) ◽

pp. 4634-4638 ◽

Cited By ~ 19

Author(s):

C. Paulo ◽

J. E. Puskas ◽

S. Angepat

Keyword(s):

Reaction Conditions ◽

Kinetics Of

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MATHEMATICAL MODELING TIME INHOMOGENEOUS KINETICS OF POLYMERIZATION

Mathematical Methods in Technologies and Technics ◽

10.52348/2712-8873_mmtt_2021_1_106 ◽

2021 ◽

pp. 106-110

Author(s):

S.E. Zakiev ◽

Yu.P. Kvurt

Keyword(s):

Mathematical Modeling ◽

Kinetics Of Polymerization ◽

Kinetics Of

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Comparative kinetics of the alkali-catalyzed sunflower oil methanolysis with co-solvent under conventional and microwave heating with controlled cooling

Green Processing and Synthesis ◽

10.1515/gps-2017-0038 ◽

2018 ◽

Vol 7 (5) ◽

pp. 441-452

Author(s):

Biljana B. Beljic Durkovic ◽

Jelena D. Jovanovic ◽

Borivoj K. Adnadjevic

Keyword(s):

Microwave Heating ◽

Sunflower Oil ◽

Conventional Heating ◽

Controlled Cooling ◽

Pseudo First Order Reaction ◽

Reaction Rate Constants ◽

Cooling Conditions ◽

Exponential Factors ◽

The Impact ◽

Kinetics Of

Abstract The kinetics of the alkali-catalyzed transesterification of sunflower oil with methanol in the presence of co-solvent (TSMPC) were investigated. The kinetics curves of the alkali-catalyzed TSMPC, in the temperature range of 26°C–55°C, were measured for conventional heating (CH) and microwave heating with controlled cooling. The results showed that for both heating modes, the kinetics of the alkali-catalyzed TSMPC reaction can be described with the kinetic model of the pseudo first-order reaction with respect to the concentration of the triglycerides. The values of apparent reaction rate constants, activation energies, and pre-exponential factors are also calculated. The existence of a linear correlation (compensation effect) between the values of apparent kinetic parameters determined for CH and microwave heating with controlled cooling conditions is established. The results confirmed that the increase in the transesterification rate in the microwave heating with controlled cooling conditions is not caused by overheating nor by the existence of hotspots. The model of mechanism of the impact of microwave heating on the kinetics of transesterification is hereby proposed.

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