scholarly journals Mechanism Analysis and Kinetic Modelling of Cu NPs Catalysed Glycerol Conversion into Lactic Acid

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 231 ◽  
Author(s):  
Sergey Zavrazhnov ◽  
Anton Esipovich ◽  
Sergey Zlobin ◽  
Artem Belousov ◽  
Andrey Vorotyntsev
Keyword(s):  
Experimental Data ◽  
Lactic Acid ◽  
Activation Barrier ◽  
Kinetic Modelling ◽  
Batch Reactor ◽  
Alkaline Media ◽  
Reaction Pathways ◽  
Model Parameters ◽  
Mechanism Analysis ◽  
Glycerol Conversion

Mechanism analysis and kinetic modeling of glycerol conversion into lactic acid in the alkaline media with and without heterogeneous catalyst Cu NPs are reported. The reaction pathways were determined in agreement with the experimental results and comprise several types of reactions, namely dehydrogenation, hydrogenolysis, dehydration and C–C cleavage. Experimental concentration-time profiles were obtained in a slurry batch reactor at different glycerol, NaOH and Cu NPs concentrations in a temperature range of 483–518 K. Power law, Langmuir–Hinshelwood (LH) and Eley–Rideal (ER) models were chosen to fit the experimental data. The proposed reaction pathways and obtained kinetic model adequately describe the experimental data. The reaction over Cu NPs catalyst in the presence of NaOH proceeds with a significantly lower activation barrier (Ea = 81.4 kJ∙mol−1) compared with the only homogeneous catalytic conversion (Ea = 104.0 kJ∙mol−1). The activation energy for glycerol hydrogenolysis into 1,2-propanediol on the catalyst surface without adding hydrogen is estimated of 102.0 kJ∙mol−1. The model parameters obtained in this study would be used to scale an industrial unit in a reactor modeling.

scholarly journals Production of lactic acid from cellulose using solid catalyst

2019 ◽  
Vol 268 ◽  
pp. 07006 ◽  
Author(s):  
Sujitra Doungsri ◽  
P. Rattanaphanee ◽  
Aatichat Wongkoblap
Keyword(s):  
Lactic Acid ◽  
Batch Reactor ◽  
Nitrogen Pressure ◽  
Reaction Pathways ◽  
Solid Catalyst ◽  
One Pot ◽  
Solid Catalysts ◽  
Platform Chemicals ◽  
Acid And Base ◽  
The One

Lactic acid (LA), one of the important biomass derived platform chemicals, has been used in food and chemical industries, especially in biodegradable polymer as polylactic acid (PLA). The aim of this work is to study the one-pot production of LA from cellulose by using different solid catalysts. The reaction was conducted in a high pressure batch reactor and the catalyst used in this study were ZrO2 and Al2O3. The reaction was carried out at temperature of 200oC for 6 hr. and under nitrogen pressure of 1 MP. It was found that the production yield of LA were 8.02% and 6.63%, when the ZrO2 and Al2O3 catalysts were used respectively. The result indicated that the ZrO2 may effect on the LA production because of the acid and base sites of the ZrO2. Therefore, the reaction pathways for conversion of cellulose into lactic acid have been investigated, and developed the new conditions to achieve the higher yield.

scholarly journals Heterogeneous catalytic reaction of glycerol with acetone for solketal production

2019 ◽  
Vol 268 ◽  
pp. 07004
Author(s):  
Hary Sulistyo ◽  
Indri Hapsari ◽  
Budhijanto ◽  
Wahyudi Budi Sediawan ◽  
Suprihastuti Sri Rahayu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Batch Reactor ◽  
Catalyst Loading ◽  
Fuel Additive ◽  
Proper Treatment ◽  
Heterogeneous Catalytic Reaction ◽  
Glycerol Conversion ◽  
Amberlyst 15 ◽  
Heterogeneous Catalytic ◽  
Catalyst Load

The rapid growth of biodiesel industries has also increased the production of glycerol as side product. Without proper treatment, glycerol may cause serious problem for the environment. Glycerol can be reacted with acetone to produce solketal as a fuel additive. The aim of this research was to study the glycerol ketalization with acetone using Amberlyst-15 as catalyst. Experiments were undertaken in a batch reactor. A set of experiment was conducted at varying temperature (35 to 60oC), initial mole ratio of acetone to glycerol (2 – 6) and catalyst loading (1,3,5 and 7% w/w). Sample was analyzed every 30 minutes. The results showed that optimal condition was achieved at temperature of 60 °C, initial mole ratio of acetone to glycerol of 3, and the catalyst load of 3%. The highest glycerol conversion achieved was 87.41 % at 60oC for 3 hours reaction. The Pseudo Steady State Hypothesis (PSSH) has been developed as rnet =k4.CG.CAC/1+k5.CG. Parameter estimation of k4 and k5 were evaluated from experimental data at various temperatures. It appears that the model predicted the experimental data well at high conversion (above 80 min) and showed relatively poor prediction below 80 min.

scholarly journals Growth Limits of Listeria monocytogenesas a Function of Temperature, pH, NaCl, and Lactic Acid

2000 ◽  
Vol 66 (11) ◽  
pp. 4979-4987 ◽  
Author(s):  
S. Tienungoon ◽  
D. A. Ratkowsky ◽  
T. A. McMeekin ◽  
T. Ross
Keyword(s):  
Experimental Data ◽  
Logistic Regression ◽  
Lactic Acid ◽  
Model Parameters ◽  
Food Borne ◽  
Food Borne Illness ◽  
Effects Of Temperature ◽  
Growth Limits ◽  
Food Safety Risk ◽  
Temperature Water

ABSTRACT Models describing the limits of growth of pathogens under multiple constraints will aid management of the safety of foods which are sporadically contaminated with pathogens and for which subsequent growth of the pathogen would significantly increase the risk of food-borne illness. We modeled the effects of temperature, water activity, pH, and lactic acid levels on the growth of two strains ofListeria monocytogenes in tryptone soya yeast extract broth. The results could be divided unambiguously into “growth is possible” or “growth is not possible” classes. We observed minor differences in growth characteristics of the two L. monocytogenes strains. The data follow a binomial probability distribution and may be modeled using logistic regression. The model used is derived from a growth rate model in a manner similar to that described in a previously published work (K. A. Presser, T. Ross, and D. A. Ratkowsky, Appl. Environ. Microbiol. 64:1773–1779, 1998). We used “nonlinear logistic regression” to estimate the model parameters and developed a relatively simple model that describes our experimental data well. The fitted equations also described well the growth limits of all strains of L. monocytogenesreported in the literature, except at temperatures beyond the limits of the experimental data used to develop the model (3 to 35°C). The models developed will improve the rigor of microbial food safety risk assessment and provide quantitative data in a concise form for the development of safer food products and processes.

Parameter Determination for Chloride and Tritium Transport in Undisturbed Lysimeters during Steady Flow

1992 ◽  
Vol 23 (2) ◽  
pp. 89-104 ◽  
Author(s):  
Ole H. Jacobsen ◽  
Feike J. Leij ◽  
Martinus Th. van Genuchten
Keyword(s):  
Experimental Data ◽  
Unsaturated Flow ◽  
Transport Model ◽  
Time Moment ◽  
Breakthrough Curves ◽  
Coarse Sand ◽  
Retardation Factor ◽  
Parameter Determination ◽  
Model Parameters ◽  
Water Fraction

Breakthrough curves of Cl and 3H2O were obtained during steady unsaturated flow in five lysimeters containing an undisturbed coarse sand (Orthic Haplohumod). The experimental data were analyzed in terms of the classical two-parameter convection-dispersion equation and a four-parameter two-region type physical nonequilibrium solute transport model. Model parameters were obtained by both curve fitting and time moment analysis. The four-parameter model provided a much better fit to the data for three soil columns, but performed only slightly better for the two remaining columns. The retardation factor for Cl was about 10 % less than for 3H2O, indicating some anion exclusion. For the four-parameter model the average immobile water fraction was 0.14 and the Peclet numbers of the mobile region varied between 50 and 200. Time moments analysis proved to be a useful tool for quantifying the break through curve (BTC) although the moments were found to be sensitive to experimental scattering in the measured data at larger times. Also, fitted parameters described the experimental data better than moment generated parameter values.

scholarly journals Modelling the Inflation and Elastic Instabilities of Rubber-Like Spherical and Cylindrical Shells Using a New Generalised Neo-Hookean Strain Energy Function

2021 ◽  
Author(s):  
Afshin Anssari-Benam ◽  
Andrea Bucchi ◽  
Giuseppe Saccomandi
Keyword(s):  
Experimental Data ◽  
Energy Function ◽  
Limit Point ◽  
Strain Energy ◽  
Cylindrical Shells ◽  
Strain Energy Function ◽  
Model Parameters ◽  
Wide Range ◽  
Cylindrical Tubes ◽  
Gent Model

AbstractThe application of a newly proposed generalised neo-Hookean strain energy function to the inflation of incompressible rubber-like spherical and cylindrical shells is demonstrated in this paper. The pressure ($P$ P ) – inflation ($\lambda $ λ or $v$ v ) relationships are derived and presented for four shells: thin- and thick-walled spherical balloons, and thin- and thick-walled cylindrical tubes. Characteristics of the inflation curves predicted by the model for the four considered shells are analysed and the critical values of the model parameters for exhibiting the limit-point instability are established. The application of the model to extant experimental datasets procured from studies across 19th to 21st century will be demonstrated, showing favourable agreement between the model and the experimental data. The capability of the model to capture the two characteristic instability phenomena in the inflation of rubber-like materials, namely the limit-point and inflation-jump instabilities, will be made evident from both the theoretical analysis and curve-fitting approaches presented in this study. A comparison with the predictions of the Gent model for the considered data is also demonstrated and is shown that our presented model provides improved fits. Given the simplicity of the model, its ability to fit a wide range of experimental data and capture both limit-point and inflation-jump instabilities, we propose the application of our model to the inflation of rubber-like materials.

scholarly journals Determination of exothermic batch reactor specific model parameters

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Specific Model ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Model Parameters ◽  
Reactor Model ◽  
First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

A Theoretical Analysis of CO2 Absorption in Sun Versus Shade Leaves

1978 ◽  
Vol 100 (1) ◽  
pp. 20-24 ◽  
Author(s):  
R. H. Rand
Keyword(s):  
Experimental Data ◽  
Quantitative Estimate ◽  
Geometric Model ◽  
Model Parameters ◽  
Co2 Absorption ◽  
Temperature Model ◽  
Spongy Mesophyll ◽  
One Dimensional ◽  
Mesophyll Tissue ◽  
Shade Leaves

A one-dimensional, steady-state, constant temperature model of diffusion and absorption of CO2 in the intercellular air spaces of a leaf is presented. The model includes two geometrically distinct regions of the leaf interior, corresponding to palisade and spongy mesophyll tissue, respectively. Sun, shade, and intermediate light leaves are modeled by varying the thicknesses of these two regions. Values of the geometric model parameters are obtained by comparing geometric properties of the model with experimental data of other investigators found from dissection of real leaves. The model provides a quantitative estimate of the extent to which the concentration of gaseous CO2 varies locally within the leaf interior.

scholarly journals MODELING AND OPTIMIZATION OF LACTIC ACID SYNTHESIS BY THE ALKALINE DEGRADATION OF FRUCTOSE IN A BATCH REACTOR

2005 ◽  
Vol 192 (6) ◽  
pp. 758-786 ◽  
Author(s):  
M. Cabassud ◽  
P. Cognet ◽  
V. Garcia ◽  
M. V. LE LANN ◽  
G. Casamatta ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Batch Reactor ◽  
Acid Synthesis ◽  
Alkaline Degradation ◽  
Modeling And Optimization
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