Kinetics of individual reactions in reaction network 1-butanol-di-(1-butyl) ether-butenes-water on alumina

1986 ◽  
Vol 51 (4) ◽  
pp. 774-785 ◽  
Author(s):  
František Krampera ◽  
Ludvík Beránek
Keyword(s):  
Complex System ◽  
Reaction Network ◽  
Rate Equations ◽  
Butyl Ether ◽  
Alcohol Dehydration ◽  
Consecutive Reaction ◽  
Best Fitting ◽  
Kinetics Of

The complex system of six reactions occurring when 1-butanol is dehydrated on alumina at 260 °C was investigated. Initial kinetics of 1-butanol, di-(1-butyl) ether and 1-butene transformations were analyzed and best fitting rate equations for all reactions were selected. The inhibiting effects of water on initial rates was quantitatively expressed. Very low conversion data provided additional evidence for the validity of the parallel-consecutive reaction network of alcohol dehydration. In all the alkene-forming reactions, 1-butene was the primary product which was then isomerized into a mixture of cis- and trans-2-butenes.

Kinetics of individual steps in reaction network ethanol-diethyl ether-ethylene-water on alumina

1986 ◽  
Vol 51 (4) ◽  
pp. 763-773 ◽  
Author(s):  
Vladimír Morávek ◽  
Miloš Kraus
Keyword(s):  
Diethyl Ether ◽  
Reaction Network ◽  
Reaction Rates ◽  
Rate Equations ◽  
Initial Reaction ◽  
Ethanol Dehydration ◽  
Partial Pressures ◽  
Type Rate ◽  
Kinetics Of ◽  
Hydrolysis Of

The rates of single reactions have been measured at 250 °C in the complex reaction of ethanol dehydration to ethylene and to diethyl ether involving also hydrolysis of the ether, its disproportionation to ethanol and ethylene and its dehydration to ethylene. The found dependences of the initial reaction rates on partial pressures of the reactants were correlated by semiempirical Langmuir-Hinshelwood type rate equations.

Kinetics of 1-butanol, di-(1-butyl) ether and 1-butene reactions on aluminas partially deactivated by sodium

1989 ◽  
Vol 54 (11) ◽  
pp. 2985-2997 ◽  
Author(s):  
František Krampera ◽  
Ludvík Beránek
Keyword(s):  
Vapour Phase ◽  
Reaction Rates ◽  
Product Formation ◽  
Sodium Content ◽  
Butyl Ether ◽  
Deactivation Kinetics ◽  
Two Factors ◽  
Best Fitting ◽  
The Individual ◽  
Kinetics Of

The initial rates of six reactions taking place in 1-butanol dehydration at 260 °C in vapour phase were measured on aluminia samples differing in sodium content. The reactants were 1-butanol, di-(1-butyl) ether and 1-butene, resp. The parameters of the best fitting rate equation for each reaction were evaluated. The reaction rates as well as the rate constants and adsorption coefficients of the individual reactions show different sensitivity to datalyst acidity. Therefore, the selectivity of product formation can be influenced by sodium content of the catalyst. The selectivities (with the exception of 1-butene izomerization) strongly depend also on the partial pressure of the starting reactants. Thus, these two factors can be used to control the selectivity for preparative purposes. The results of this paper clearly demonstrate the nonseparability of the deactivation kinetics in 1-butanol dehydration on sodium poisoned aluminas.

scholarly journals Biochemical Engineering Parameters for Hydrometallurgical Processes: Steps towards a Deeper Understanding

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. Kundu ◽  
A. Kumar
Keyword(s):  
Redox Potential ◽  
Metal Ion ◽  
Good Control ◽  
Point Of View ◽  
Rate Equations ◽  
Biochemical Engineering ◽  
Mining Operations ◽  
Feasible Option ◽  
Engineering Parameters ◽  
Kinetics Of

Increasing interest in biomining process and the demand for better performance of the process has led to a new insight toward the mining technologies. From an engineering point of view, the complex network of biochemical reactions encompassed in biomining would best be performed in reactors which allow a good control of the significant variables, resulting in a better performance. The subprocesses are in equilibrium when the rate of particular metal ion; for example, iron turnover between the mineral and the bacteria, is balanced. The primary focus is directed towards improved bioprocess kinetics of the first two subprocesses of chemical reaction of the metal ion with the mineral and later bacterial oxidation. These subprocesses are linked by the redox potential and controlled by maintenance of an adequate solids suspension, dilution rate, and uniform mixing which are optimised in bioreactors during mining operations. Rate equations based on redox potential such as ferric/ferrous-iron ratio have been used to describe the kinetics of these subprocesses. This paper reviews the basis of process design for biomining process with emphasis on engineering parameters. It is concluded that the better understanding of these engineering parameters will make biomining processes more robust and further help in establishing it as a promising and economically feasible option over other hydrometallurgical processes worldwide.

scholarly journals Dependence upon Bile Volume of the Biliary Excretion of Bromocresol Green and Amaranth in the Anaesthetized Rat

1975 ◽  
Vol 28 (4) ◽  
pp. 339 ◽  
Author(s):  
Alan G Clark ◽  
KarI M Rogers
Keyword(s):  
Biliary Excretion ◽  
Biliary Tree ◽  
Bulk Flow ◽  
Rate Equations ◽  
Bromocresol Green ◽  
Limiting Factor ◽  
Cumulative Volume ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Anaesthetized Rat

The kinetics of the biliary excretion of both bromocresol green and amaranth are better described in terms of rate equations that are functions of the cumulative volume of bile excreted rather than of time. The rate of disappearance of bromocresol green from the liver also appears to depend on the volume of bile excreted rather than on time. It is proposed that bromocresol green, and probably also amaranth, rapidly equilibrates between the hepatic and biliary compartments as a result of reabsorption from the biliary tree and that the rate-limiting factor in the biliary excretion of these dyes is the removal of dye from the biliary tree by bulk flow.

Passage rate of solids and fluids in the digestive tract of buffaloes, cattle and sheep: selection of non-linear model

1997 ◽  
Vol 64 (1) ◽  
pp. 63-69 ◽  
Author(s):  
A. Amici ◽  
S. Bartocci ◽  
S. Terramoccia ◽  
F. Martillotti
Keyword(s):  
Linear Models ◽  
Latin Square ◽  
Sums Of Squares ◽  
Passage Rate ◽  
Significant Difference ◽  
Age Dependent ◽  
Non Linear ◽  
Best Fitting ◽  
Kinetics Of ◽  
Selection Of

AbstractFive mathematical models were compared to select the most satisfactory model to describe digesta kinetics of solids and fluids in the gastrointestinal tract of buffaloes (Mediterranean bulls), cattle (Friesian bulls) and sheep (Delle Langhe rams) given food at maintenance level, according to a Latin-square arrangement for four consecutive periods of 21 days. Chromium mordanted alfalfa hay and cobalt-ethylenediamine tetraacetic acid were used as nonabsorbable markers and were administered through the rumen cannula in a single dose. Four different isonitrogenous diets (N × 6·25 = 140 g/kg dry matter) with different concentrate:forage ratios (12·5:87·5, 25:75, 37·5:62·5, 50:50) were used.Faecal chromium and cobalt concentration curves were fitted with five non-linear models: three gamma (G2, G3, G4) age-dependent one-compartment, one gamma age-dependent/age-independent two-compartment (G2G1) and one multicompartment (MC).Wilcoxon tests on residual sums of squares of the different models for solids showed that MC and G4 gave a better fit than G2G1, G2, G3 for all the data and within the species. The comparison of MC v. G4 did not show any significant difference (P > 0·05) for all the data computed together or within each species. Nevertheless, MC had a higher number of curves with lower residual sums of squares in comparison with G4 and was also able to produce estimates of digesta kinetics in the second compartment.The cobalt excretion curves for fluids, considering all the data, and only within sheep, showed G4 as the best fitting model. When G4 was compared with other models no significant differences were recorded either for cattle: G4 v. G2 (F = 0·6645), G4 v. G2G1 (P = 0·0620) and for buffalo: G4 v. G2 (P = 0·1575), G4 v.G3(P = 0·0796) and G4 v. G2G1 (P = 0·1641).It is concluded that the multicompartment model (MC) and G4 model were the best fits for solids and for fluids respectively.

scholarly journals Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 516 ◽  
Author(s):  
Michela Lucian ◽  
Maurizio Volpe ◽  
Luca Fiori
Keyword(s):  
Experimental Data ◽  
Reaction Kinetics ◽  
Reaction Pathway ◽  
Hydrothermal Carbonization ◽  
Kinetics Model ◽  
Transient Phase ◽  
Lumped Model ◽  
Gaseous Products ◽  
Best Fitting ◽  
Kinetics Of

Olive trimmings (OT) were used as feedstock for an in-depth experimental study on the reaction kinetics controlling hydrothermal carbonization (HTC). OT were hydrothermally carbonized for a residence time τ of up to 8 h at temperatures between 180 and 250 °C to systematically investigate the chemical and energy properties changes of hydrochars during HTC. Additional experiments at 120 and 150 °C at τ = 0 h were carried out to analyze the heat-up transient phase required to reach the HTC set-point temperature. Furthermore, an original HTC reaction kinetics model was developed. The HTC reaction pathway was described through a lumped model, in which biomass is converted into solid (distinguished between primary and secondary char), liquid, and gaseous products. The kinetics model, written in MATLABTM, was used in best fitting routines with HTC experimental data obtained using OT and two other agro-wastes previously tested: grape marc and Opuntia Ficus Indica. The HTC kinetics model effectively predicts carbon distribution among HTC products versus time with the thermal transient phase included; it represents an effective tool for R&D in the HTC field. Importantly, both modeling and experimental data suggest that already during the heat-up phase, biomass greatly carbonizes, in particular at the highest temperature tested of 250 °C.

Incorporating covalent and allosteric effects into rate equations: the case of muscle glycogen synthase

2014 ◽  
Vol 462 (3) ◽  
pp. 525-537 ◽  
Author(s):  
Daniel C. Palm ◽  
Johann M. Rohwer ◽  
Jan-Hendrik S. Hofmeyr
Keyword(s):  
Kinetic Parameters ◽  
Equilibrium Constant ◽  
Muscle Glycogen ◽  
Glycogen Synthase ◽  
Covalent Modification ◽  
Rate Equations ◽  
Phosphorylation State ◽  
Kinetics Of

The kinetics of muscle glycogen synthase in different phosphorylation states can be described with the same set of kinetic parameters by an adapted Monod–Wyman–Changeux equation in which covalent modification alters the T/R (taut/relaxed) equilibrium constant, L0. Only L0 depends on the phosphorylation state.

scholarly journals MATHEMATICAL MODELING OF ORANGE SEED DRYING KINETICS

2015 ◽  
Vol 39 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Daniele Penteado Rosa ◽  
Denis Cantú-Lozano ◽  
Guadalupe Luna-Solano ◽  
Tiago Carregari Polachini ◽  
Javier Telis-Romero
Keyword(s):  
Mathematical Modeling ◽  
Thin Layer ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Waste Products ◽  
Juice Processing ◽  
Diffusive Model ◽  
Best Fitting ◽  
Drying Curves ◽  
Kinetics Of

Drying of orange seeds representing waste products from juice processing was studied in the temperatures of 40, 50, 60 and 70 °C and drying velocities of 0.6, 1.0 and 1.4 m/s. Experimental drying kinetics of orange seeds were obtained using a convective air forced dryer. Three thin-layer models: Page model, Lewis model, and the Henderson-Pabis model and the diffusive model were used to predict the drying curves. The Henderson-Pabis and the diffusive models show the best fitting performance and statistical evaluations. Moreover, the temperature dependence on the effective diffusivity followed an Arrhenius relationship, and the activation energies ranging from 16.174 to 16.842 kJ/mol

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