Kinetic Studies of Hydrodeoxygenation of Ethyl Ester of Decane Acid over a Ni-Cu-Mo/Al2O3 Catalyst

2019 ◽  
Vol 19 (1) ◽  
pp. 33-39
Author(s):  
R. G. Kukushkin ◽  
S. I. Reshetnikov ◽  
S. G. Zavarukhin ◽  
P. M. Eletskiy ◽  
V. A. Yakovlev
Keyword(s):  
Contact Time ◽  
Noble Metals ◽  
Flow Reactor ◽  
Experimental Studies ◽  
Kinetic Studies ◽  
Nickel Catalysts ◽  
Effective Rate ◽  
Main Reaction ◽  
Reaction Products ◽  
Fixed Catalyst

Nickel-based catalysts for hydrodeoxygenation of vegetable oils are an alternative to the systems based on noble metals and sulfide catalysts for hydrotreatment. Modification of the nickel catalysts with molybdenum and copper allows the yield of target products to be increased and the corrosion resistance of the catalytic system to be improved. The studies were aimed at establishing relationships between temperature, contact time and activity of the modified nickel-containing catalyst to hydroxygenation of esters of fatty carboxylic acids, as well as at determining effective kinetic parameters of the reactant consumption. A flow reactor with the fixed catalyst bed was used for experimental studies at РН2 = 0.25 MPa, temperatures 270, 285, 300 and 315 °C, contact time varied from 600 to 1800 s. It was shown that the selectivity to the main reaction products – nonane and decane – did not change upon varying the reaction temperature and contact time. The experimental data were used for determining the effective rate constants and activation energy of the reaction.

scholarly journals OXIDATIVE-REDUCING PROCESSES WITH PARTICIPATION OF MANGANESE IONS INITIATED BY AN ELECTRIC DISCHARGE IN AQUEOUS SOLUTION

2018 ◽  
Vol 61 (9-10) ◽  
pp. 23-29 ◽  
Author(s):  
Dmitriy A. Shutov ◽  
Aleksandra V. Sungurova ◽  
Kristina V. Smirnova ◽  
Anna S. Manukyan ◽  
Vladimir V. Rybkin
Keyword(s):  
Aqueous Solution ◽  
Electric Discharge ◽  
Rate Constants ◽  
Experimental Studies ◽  
Effective Rate ◽  
Solid Particles ◽  
Manganese Ions ◽  
Reaction Products ◽  
X Ray ◽  
Kinetics Of

The results of experimental studies of the kinetics of oxidation-reduction of Mn7+ ions (MnO4-) in aqueous solutions initiated by the action of a discharge of a direct current of atmospheric pressure in air are analyzed in the article. A solution of potassium permanganate served as a discharge cathode. The range of initial solution concentrations for Mn7+ ions was (0.44-2.5) mmol/l, and discharge currents (20-60) mA. It was found that the discharge action leads to the reduction of Mn7+ ions and discoloration of the solution. At the same time, dark solid particles with a size of 0.1 μm to 20 μm are formed. X-ray diffraction analysis showed that the particles are amorphous, and energy dispersive X-ray analysis showed that the powder is manganese oxide (IV). The kinetics of reduction-oxidation of Mn7+ ions is measured. It is shown that the obtained data on the kinetics of the reduction of Mn7+ ions in the best way (the determination coefficient R2≈0.99) can be described by the scheme X↔Y↔Z, where X is the starting material, and Y and Z are the reaction products. The processing of kinetic curves on the basis of this scheme found the effective rate constants of the corresponding stages. It was found that the effective rate constants depend on the initial concentration of the solution. At a discharge current of 20 mA, an increase in the concentration from 0.44 to 2.5 mol/l led to a decrease in the rate constant for the reduction of Mn7+ ions from (2.48 ± 0.5) ·10-2 to (7.2 ± 1.5) ·10-3 s-1, respectively. Possible mechanisms of processes are discussed. It is assumed that the main particles involved in the oxidation reactions of the reduction of manganese ions are H2O2, HO2, OH and solvated electrons that are formed in the solution under the action of a discharge. For citation: Shutov D.A., Sungurova A.V., Smirnova K.V., Manukyan A.S., Rybkin V.V. Oxidative-reducing processes with participation of manganese ions initiated by electric discharge in aqueous solution. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 23-29

scholarly journals Heterogeneously Catalyzed γ-Valerolactone Hydrogenation into 1,4-Pentanediol in Milder Reaction Conditions

Reactions ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 54-71
Author(s):  
Irina Simakova ◽  
Yulia Demidova ◽  
Mikhail Simonov ◽  
Sergey Prikhod’ko ◽  
Prashant Niphadkar ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Effect Of Temperature ◽  
Main Reaction ◽  
Reaction Products ◽  
Continuous Flow Reactor ◽  
Transmission Electron ◽  
Cu Catalysts ◽  
Temperature Programmed

Hydrogenation of γ-valerolactone (GVL) in polar solvents (n-butanol, 1,4-dioxane) to 1,4-pentanediol (PDO) and 2-methyltetrahydrofuran (MTHF) was performed at 363–443 K in a fixed bed reactor under overall H2 pressure of 0.7–1.3 MPa. Preliminary screening in a batch reactior was performed with a series of Ru, Ir, Pt, Co, and Cu catalysts, earlier efficiently applied for levulinic acid hydrogenation to GVL. The fresh catalysts were analyzed by transmission electron microscopy (TEM), X-ray fluorescent analysis (XRF), temperature programmed reduction by H2 (H2-TPR), and N2 physisorption. Cu/SiO2 prepared by reduction of copper hydroxosilicate with chrysocolla mineral structure provided better selectivity of 67% towards PDO at 32% GVL conversion in a continuous flow reactor. This catalyst was applied to study the effect of temperature, hydrogen pressure, and contact time. The main reaction products were PDO, MTHF, and traces of pentanol, while no valeric acid was observed. Activity and selectivity to PDO over Cu/SiO2 did not change over 9 h, indicating a fair resistance of copper to leaching.

Hydrogenolysis of glucose and fructose in glycol solutions over CuO-MgO-ZrO2 catalyst

2020 ◽  
pp. 48-55
Author(s):  
M.E. Sharanda ◽  
◽  
E.A. Bondarenko ◽  
Keyword(s):  
Ethylene Glycol ◽  
Propylene Glycol ◽  
Flow Reactor ◽  
General Trend ◽  
Raw Materials ◽  
Reaction Products ◽  
Renewable Raw Materials ◽  
High Partial Pressure ◽  
Zro2 Catalyst ◽  
Phase Process

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.

Kinetics of the catalytic hydrodesulphurization reaction system; hydrogenolysis of thiophene

1980 ◽  
Vol 45 (10) ◽  
pp. 2728-2741 ◽  
Author(s):  
Pavel Fott ◽  
Petr Schneider
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Flow Reactor ◽  
Kinetic Equations ◽  
Reaction System ◽  
Reaction Products ◽  
Molybdenum Catalyst ◽  
Cobalt Molybdenum Catalyst ◽  
Kinetics Of ◽  
Reaction Schemes

Kinetics have been studied of the reaction system taking place during the reaction of thiophene on the cobalt-molybdenum catalyst in a gradientless circulation flow reactor at 360 °C and atmospheric pressure. Butane has been found present in a small amount in the reaction products even at very low conversion. In view of this, consecutive and parallel-consecutive (triangular) reaction schemes have been proposed. In the former scheme the appearance of butane is accounted for by rate of desorption of butene being comparable with the rate of its hydrogenation. According to the latter scheme part of the butane originates from thiophene via a different route than through hydrogenation of butene. Analysis of the kinetic data has revealed that the reaction of thiophene should be considered to take place on other active sites than that of butene. Kinetic equations derived on this assumption for the consecutive and the triangular reaction schemes correlate experimental data with acceptable accuracy.

scholarly journals Characterization and Structural Insights of the Reaction Products by Direct Leaching of the Noble Metals Au, Pd and Cu with N,N′-Dimethyl-piperazine-2,3-dithione/I2 Mixtures

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4721
Author(s):  
Angela Serpe ◽  
Luca Pilia ◽  
Davide Balestri ◽  
Luciano Marchiò ◽  
Paola Deplano
Keyword(s):  
Density Functional ◽  
Noble Metals ◽  
Density Functional Theory Calculations ◽  
Metal Powders ◽  
Reaction Products ◽  
Metal Recycling ◽  
Direct Leaching ◽  
Tetrahedral Complexes ◽  
Organic Solutions ◽  
Structural Insights

In the context of new efficient and safe leaching agents for noble metals, this paper describes the capability of the Me2pipdt/I2 mixture (where Me2pipdt = N,N′-dimethyl-piperazine-2,3-dithione) in organic solutions to quantitatively dissolve Au, Pd, and Cu metal powders in mild conditions (room temperature and pressure) and short times (within 1 h in the reported conditions). A focus on the structural insights of the obtained coordination compounds is shown, namely [AuI2(Me2pipdt)]I3 (1), [Pd(Me2pipdt)2]I2 (2a) and [Cu(Me2pipdt)2]I3 (3), where the metals are found, respectively, in 3+, 2+ and 1+ oxidation states, and of [Cu(Me2pipdt)2]BF4 (4) and [Cu(Me2dazdt)2]I3 (5) (Me2dazdt = N,N′-dimethyl-perhydrodizepine-2,3-dithione) compared with 3. Au(III) and Pd(II) (d8 configuration) form square–planar complexes, whereas Cu(I) (d10) forms tetrahedral complexes. Density functional theory calculations performed on the cationic species of 1–5 help to highlight the nature of the bonding in the different complexes. Finally, the valorization of the noble metals-rich leachates is assessed. Specifically, gold metal is quantitatively recovered from the solution besides the ligands, showing the potential of these systems to promote metal recycling processes.

scholarly journals Organic Dyes Adsorption on the Almond Shell (Prunus dulcis) as Agricultural Solid Waste from Aqueous Solution in Single and Binary Mixture Systems

2021 ◽  
Vol 12 (2) ◽  
pp. 2022-2040
Keyword(s):  
Aqueous Solution ◽  
Binary Mixture ◽  
Contact Time ◽  
Binary Systems ◽  
Organic Dyes ◽  
Low Cost ◽  
Kinetic Studies ◽  
Prunus Dulcis ◽  
Order Kinetic ◽  
Almond Shell

Almond shell (AS) is a low-cost adsorbent used in this study for the removal of methylene blue (MB), crystal violet (CV), and Congo red (CR) from an aqueous solution in single and mixture binary systems. The low-cost adsorbent was characterized by FTIR and SEM analysis. The effects of AS dose, contact time, initial dye concentration, pH, and temperature on MB, CV, and CR adsorption were studied in a single system. In a binary system, the MB, CV, and CR were removed from the mixture of MB+CR, CV+MB, and CV+CR with a percentage in volume ranging from 0 to 100 % in MB and CV, and CR. Kinetic studies showed rapid sorption following a second-order kinetic model with of contact time of 10 min. The modulation of adsorption isotherms showed that retention follows the Langmuir model. The thermodynamic parameters proved that the MB, CV, and CR adsorption process was feasible, spontaneous, and exothermic. The synergy adsorption between dyes in a binary mixture of MB+CR and CV+CR, while the competition adsorption between dyes in a binary mixture of MB+ CV.

scholarly journals Detection and antimicrobial activity of immobilized quaternary ammonium antimicrobial monolayers on porous and non-porous surfaces.

2021 ◽  
Author(s):  
Lukasz Porosa
Keyword(s):  
Antimicrobial Activity ◽  
Phosphonic Acid ◽  
Quaternary Ammonium ◽  
Contact Time ◽  
Metal Surfaces ◽  
Noble Metals ◽  
Environmental Safety ◽  
Dip Coating ◽  
Surface Attachment ◽  
Thin Film Coatings

This research describes the development of novel, environmentally-friendly, non-releasing contact-active thin film coatings by immobilizing the quaternary ammonium (QA) antimicrobial group on a multitude of surfaces. Various chemical anchors based on organosilanes (i.e. textiles, silica, oxide surfaces), organosulfur comprising of thiol (noble metals), organophosphorus comprising of phosphonate and phosphonic acid (i.e. stainless steel (SS), titanium (Ti)), and catechol (Ti, SS) monolayers are employed to attach the QA antimicrobial onto metal surfaces, while benzophenone photoactive crosslinkers containing QA groups are used to coat plastic surfaces (C-H surfaces, i.e. polyethylene (PE), silicone (Si), polyvinylchloride (PVC)). Surfaces treated with covalently attached antimicrobial coatings function by killing microbes on contact, preventing surface attachment, colonization and contamination without releasing the chemical into the environment. The advantages of this method of delivery of the antimicrobial include a lower cost of application, decreased antimicrobial resistance, lower toxicity and increased environmental safety. Samples prepared by an overnight immersion in an ethanolic solution of phosphorus containing quats followed by an overnight cure at 100oC showed the highest antimicrobial reduction versus electrospray application and no curing. Short chain phosphonic acid quats and the organosilane quat were inactive on titanium. Antimicrobial activity of long chain phosphonate quats prepared by dip coating and annealing on metal surfaces (Ti, SS, Al) was tested by growth enumeration in the dry state utilizing methods developed in the Wolfaardt lab. All samples showed a 100% reduction (106 cells) of viable Salmonella, Arthrobacter, S.aureus and P.aeroguinosa after 2 hrs of contact time and maintained their activity over 24 hrs versus the uncoated controls. To demonstrate the phosphonate quats were truly immobilized, Ti samples from the first trial were washed in distilled H2O, dried, and re-innoculated with 106 Anthrobacter colonies. No visible colonies of Anthrobacter remained after 2 hrs of contact time with the Ti surfaces indicating a contact killing mechanism at play.

scholarly journals Photocatalytic Degradation of Alizarin Red-S by Fe-Co Nanoparticles Prepared By Chemical Co-precipitation Method

2015 ◽  
Vol 11 (9) ◽  
pp. 3950-3958 ◽  
Author(s):  
Chandrakant Vedu Nandre ◽  
C.P. Sawant
Keyword(s):  
Photocatalytic Degradation ◽  
Contact Time ◽  
Oxygen Demand ◽  
Kinetic Studies ◽  
Water Soluble ◽  
Precipitation Method ◽  
Alizarin Red ◽  
Co Nanoparticles ◽  
Co Precipitation ◽  
Red Dye

In the present study photocatalytic degradation of hazardous water soluble alizarin red dye by using Fe-Co nanoparticles  has been investigated. Fe-Co nanoparticles was synthesized by chemical co-precipitation method and characterized by TEM, SEM, EDAX and XRD. The photocatalytic degradation have been studied with the help of variety of parameters such as catalytic dose, dye concentration, pH, contact time and most important chemical oxygen demand. It was observed that The photocatalytic degradation of alizarin red dye by using Fe-Co nanoparticles was an effective ,economic, ecofriendly and faster mode of removing dye from an aqueous solution. The optimum condition for the degradation of the dye was 50 mg/L,pH 8.0, catalyst dose 60 mg/L and contact time 60 minutes. The kinetic studies also have been studied.

scholarly journals Preparation of isocyanates by carbamates thermolysis on the example of butyl isocyanate

2019 ◽  
Vol 58 (4) ◽  
pp. 40-47
Author(s):  
Ratmir R. Dashkin ◽  
◽  
Dmitry A. Gordeev ◽  
Khusrav Kh. Gafurov ◽  
Sergey N. Mantrov ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Performance ◽  
Gas Flow ◽  
Flow Reactor ◽  
Packed Column ◽  
Biologically Active ◽  
Dibutyltin Dilaurate ◽  
Reaction Products ◽  
Uv Detector ◽  
Laboratory Setup

Butyl isocyanate is widely distributed as a precursor for the production of a number of biologically active substances: fungicides, preservatives, insecticides, personal care products, etc. Nowadays, there are a number of methods for the preparation of isocyanates, which can be divided into liquid phase and gas phase. One of the perspective methods for the production of isocyanates is the thermolysis of carbamate and/or the actions of various reaction activating agents, accompanied by the elimination of alcohol, but this process is reversible, which greatly complicates its use in industry. The paper presents the results of studies of non-catalytic thermal decomposition of N-alkylcarbamates with the formation of alkylisocyanates on the example of butylisocyanate in the gas phase, flow reactor in a wide temperature range (200 to 450 °C). In addition, a series of experiments was carried out using a catalyst, dibutyltin dilaurate, in order to reduce the thermolysis temperature and increase the yield of the final product. To implement the isocyanate production process, an experimental laboratory setup, consisting of a gas flow meter (argon) regulator, a packed column (for heating) and a sorption solution tank, was developed and tested. The thermolysis of N-n-butylcarbamate was carried out in two variations: the preparation of an individual n-butylisocyanate and the passage of reaction products through a sorption solution linking the n-butyl isocyanate to N-n-butyl-N '-(1-phenylethyl)urea, which allows to estimate the yield of the target n-butylisocyanate without additional losses. The analysis of the obtained substances was carried out by high performance liquid chromatography with a UV detector (target product) and a mass detector (analysis of by-products). According to the results of research, a modification of the laboratory facility was proposed, as well as n-butylisocyanate was obtained with a yield of 49% on the basis of a new technique.

scholarly journals EVALUATION OF HYDROPHILIC GLOBULES WITH SODIUM ALGINATE CONTAINING A LACTIC ACID– CHITOSAN COMPLEX

2021 ◽  
Vol 26 ◽  
pp. 170-177
Author(s):  
Katarzyna Małolepsza-Jarmołowska ◽  
Keyword(s):  
Lactic Acid ◽  
Rheological Properties ◽  
Sodium Alginate ◽  
Contact Time ◽  
Experimental Studies ◽  
Vaginal Mucosa

An important issue in the treatment of vaginitis is the amount of time the drug remains on the vaginal mucosa. If the contact time is too short, the drug cannot work effectively to ensure the correct pH in the vaginal environment. This study evaluated formulations of globules containing sodium alginate, lactic acid and chitosan with different pH and rheological properties. The experimental studies revealed that it is possible to produce a preparation with optimal pharmaceutical and application properties. The use of an appropriate ratio of lactic acid to chitosan in the complex and the appropriate concentration of sodium alginate produces a preparation with excellent properties to coat the surface of the vaginal mucosa.

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