scholarly journals Experimental Studies on n-Octane and Cyclohexane as Organic Solvent for Synthesis of Polyurea Microcapsules by Interfacial Polycondensation

2018 ◽  
Vol 7 (2) ◽  
pp. 64-66
Author(s):  
Ujvala P. Christian ◽  
Shrikant J. Wagh
Keyword(s):  
Organic Solvent ◽  
Reaction Rate ◽  
Experimental Studies ◽  
Reaction System ◽  
Large Mass ◽  
Interfacial Polycondensation ◽  
Good Thermal Stability ◽  
Kinetics Of ◽  
Selection Of

Interfacial polycondensation (IP) is one of the most important step polymerization technique used for synthesis of polyurea microcapsules. IP reaction between diamine and diisocyanate monomers which are soluble in aqueous phase and organic phase respectively is very fast therefore the overall process of polyurea synthesis via interfacial polycondensation, by and large, mass transfer controlled reaction. Selection of proper organic solvent is one of the important parameter for IP reactions. The objective of this experimental work was to study the effect of n-Octane and Cyclohexane as an organic solvent on kinetics of polyurea microcapsules synthesized by interfacial polycondensation reaction. In this reaction system IP reaction occurs on organic side of the interface so reaction rate increased with increase in relative polarity of organic solvent. Characterization of polyurea was carried out by XRD and DSC which demonstrated that semi crystalline polyurea microcapsules with good thermal stability were synthesized.

Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
Author(s):  
Laurent Royer ◽  
Stéphane Mathieu ◽  
Christophe Liebaut ◽  
Pierre Steinmetz
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Molten Glass ◽  
Energy Production ◽  
Creep Properties ◽  
Refractory Alloys ◽  
Industrial Use ◽  
Kinetics Of ◽  
Selection Of

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.

Carbohydrates in alkaline systems. II. Kinetics of the transformation and degradation reactions of cellobiose, cellobiulose, and 4-O-β-D-glucopyranosyl-D-mannose in 1 M sodium hydroxide at 22 °C

1969 ◽  
Vol 47 (21) ◽  
pp. 3957-3964 ◽  
Author(s):  
Donald J. MacLaurin ◽  
John W. Green
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Column Chromatography ◽  
Rate Constants ◽  
Reaction Rate ◽  
Reaction System ◽  
Reaction Rate Constants ◽  
Degradation Reactions ◽  
Fructose 2 ◽  
Kinetics Of

Rates of isomerization, epimerization, and degradation reactions were measured for cellobiose (7), cellobiulose (8), and 4-O-β-D-glucopyranosyl-D-mannose (9) at 0.001 M in 1 M NaOH under N2 in the dark at 22 °C. Reaction system resolution was by column chromatography on anion resins in the borate form. Assay for D-glucose (1), D-fructose (2), D-mannose (3), and 7,8, and 9 was by continuous automated colorimetry of column effluent with orcinol–sulfuric acid as reagent. Reaction rate constants (h−1) found: k78 0.078, k79 0.0005, k7,10 0.002, k87 0.022, k89 0.003 k81 0.065, k8,12 0.023, k97 0.002, k98 0.013, k9,11 0.006 where 10,11, and 12 are other products than 1,2,3,7,8, and 9. Details for preparation of 8 and 9 are given.

scholarly journals Nanoscale Schottky diodes for studying the activity of aluminum nanoparticles in reaction with water

2021 ◽  
Vol 2094 (2) ◽  
pp. 022051
Author(s):  
I Nedrygailov ◽  
N I Chernova ◽  
I V Osliakova
Keyword(s):  
Reaction Rate ◽  
Schottky Diodes ◽  
Experimental Studies ◽  
Characteristic Size ◽  
Electrical Signal ◽  
Aluminum Surface ◽  
Aluminum Nanoparticles ◽  
Production And Consumption ◽  
Reaction With Water ◽  
Kinetics Of

Abstract Hydrogen is a promising fuel for energy storage, transportation, production and consumption. At the same time, hydrogen in its pure form is not found on Earth in large quantities and therefore it is necessary to develop a technology for its production. One of the promising technologies for hydrogen production is the reaction of aluminum nanoparticles with water. At the same time, experimental studies of the elementary mechanisms of this reaction are difficult due to the aggressive properties of a concentrated alkaline solution, which is used to activate the aluminum surface. Here we show that the kinetics of the aluminum-water reaction can be monitored in real time using a Schottky nanodiode sensor, provided that the characteristic size of the nanodiode electrodes does not exceed 10 nm. The investigated nanoparticles are applied to the sensor surface by means of nanofabrication. The charge generated in the aluminum nanoparticles as a result of the reaction creates an electrical signal that is proportional to the rate of the chemical process. This makes it possible to use this technology to study the activity even of small groups of nanoparticles, when the volume of released hydrogen is insufficient to measure the reaction rate.

Microfluidic Chip Injection Photo Solidification Molding Study on Reaction Kinetics

2019 ◽  
Vol 814 ◽  
pp. 481-486
Author(s):  
Jin Ge Tong ◽  
Jian Yun He ◽  
Peng Cheng Xie ◽  
Jing Hui Zhang ◽  
Zeng Qiang Shen ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Microfluidic Chip ◽  
Reaction Rate ◽  
Reaction System ◽  
Microfluidic Chips ◽  
Forming Efficiency ◽  
Chip Fabrication ◽  
On Line ◽  
Feeding Effect ◽  
Kinetics Of

Microfluidic chip injection photocuring is a new method for microfluidic chip fabrication. The accuracy of microfluidic chip photocuring has an important impact on the reliability of microfluidic chip. The reaction rate of photocuring system directly affects the final quality and efficiency of microfluidic chip. The rapid reaction rate of photocuring system will lead to poor feeding effect of the reaction system. The forming accuracy is affected, and the reaction rate is too slow, which will increase the forming time and affect the forming efficiency. In this paper, the conversion rate and reaction rate of different active monomers and oligomers used in the formulation system of microfluidic chips were measured on-line. The photocuring reaction kinetics of microfluidic chips was studied, and the influence of the formulation system on the photocuring reaction was explored, which laid a foundation for optimizing the formulation of microfluidic chips.

Kinetics of the Alkaline Solvolysis of Trichloroacetate Ion in Water-Ethanol Solutions

1978 ◽  
Vol 33 (1) ◽  
pp. 30-34
Author(s):  
I. M. Issa ◽  
E . M. Diefallah ◽  
M. R. Mahmoud ◽  
A. M. El-Nady
Keyword(s):  
Dielectric Constant ◽  
Organic Solvent ◽  
Transition State ◽  
Trichloroacetic Acid ◽  
Reaction Rate ◽  
Water Solvent ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Activated Complex ◽  
Polar Water

Abstract Alkaline Solvolysis, Trichloroacetate Ion The alkaline solvolysis of trichloroacetic acid in water-ethanol mixtures have been studied in the presence of 0.40-0.80 M sodium hydroxide within the temperature range 35-70 °C. The rate constant increased with progressive addition of the organic solvent. The dielectric constant effect on the reaction rate was investigated. The radius of the activated complex at different temperatures was calculated. The isocomposition and isodielectric energies as well as the thermodynamic parameters of activation were calculated and their significance in terms of solvent composition has been discussed. It was concluded that the reactant state is extensively higher solvated than the transition state by the highly polar (water) solvent.

Carbohydrates in alkaline systems. I. Kinetics of the transformation and degradation of D-glucose, D-fructose, and D-mannose in 1 M sodium hydroxide at 22 °C

1969 ◽  
Vol 47 (21) ◽  
pp. 3947-3955 ◽  
Author(s):  
Donald J. MacLaurin ◽  
John W. Green
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Column Chromatography ◽  
Rate Constants ◽  
Reaction Rate ◽  
Reaction System ◽  
Reaction Rate Constants ◽  
Degradation Reactions ◽  
Fructose 2 ◽  
Kinetics Of

Rates of isomerization, epimerization, and degradation reactions were measured for D-glucose (1), D-fructose (2), and D-mannose (3) at 0.002 M in 1 M NaOH under N2 in the dark at 22 °C. Reaction system resolution was by column chromatography on anion resins in the borate form. Assay for 1, 2, and 3 was by continuous automated colorimetry of column effluent using orcinol/sulfuric acid as a reagent. D-Allose and D-altrose were not detected. Reaction rate constants (h−1) found: k12 0.038, k13 0.0005, k15 0.002, k21 0.036, k23 0.006, k24 0.072, k31 0.0005, k32 0.011, k36 0.002, where 4, 5, and 6 are products formed from 1, 2, or 3, respectively.

Electrode kinetics of the system V(III)/V(II) in aqueous dimethylsulphoxide

1991 ◽  
Vol 56 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Libuše Kišová ◽  
Libor Reichstädter ◽  
Jaro Komenda
Keyword(s):  
Organic Solvent ◽  
Double Layer ◽  
Rate Constants ◽  
Electrode Surface ◽  
Reaction Rate ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Electrode Kinetics ◽  
Kinetics Of ◽  
Lower Basicity

The rate constants for the reduction of V(III) and oxidation of V(II) were measured on a mercury electrode in water and water-dimethylsulphoxide mixtures. Their dependance on the concentration of DMSO differs from that in mixtures of water with an organic solvent of lower basicity. This can be attributed to the existence of different solvates of vanadium in solutions and to different values of the rate constant for these solvates on the electrode surface at different coverages with the organic component. The influence of DMSO both in the primary solvation sphere and in the electrode double layer on the electrode reaction rate is discussed.

The Study of Biodegradation Kinetics of Starch Based on Coating in Controlled Released Fertilizer (CRF)

2013 ◽  
Vol 295-298 ◽  
pp. 240-248 ◽  
Author(s):  
Nurul Haniza Abdul Rahman ◽  
Radzuan B. Razali ◽  
Nurlidia Binti Mansor
Keyword(s):  
Release Rate ◽  
Reaction Rate ◽  
Coating Material ◽  
Biodegradation Kinetics ◽  
Coating Materials ◽  
Degradation Properties ◽  
Kinetics Of ◽  
Controlled Released ◽  
Selection Of

The aim of this study is to prepare a starch film and analyze its characteristics in different pH condition. Starch has been given great attention and has been actively investigated to be used as coating materials for CRF because of its degradation properties. Once the analysis on the starch characteristics is completed, the reaction rate of the starch can be developed by using Michaelis-Menten equation as reference. The results of the reaction rate are important to help determine the biodegradation kinetics of the starch. It will also assist in determining the conditions needed to produce the starch film in order to reduce the release rate of fertilizer. Throughout this study, the biodegradation kinetics of starch film will be investigated and thus providing a reference for the selection of coating material for the application of CRF while improving agriculture production.

Synthesis and Characterization of Modified Zn-Antibacterial White Carbon Black

2010 ◽  
Vol 150-151 ◽  
pp. 522-525
Author(s):  
Bin Zhang ◽  
Xiao Ning Tang ◽  
Tao He ◽  
Su Qiong He ◽  
Wen Rong Yao
Keyword(s):  
Carbon Black ◽  
Organic Solvent ◽  
Inductively Coupled Plasma ◽  
Sol Gel ◽  
Measurement Instrument ◽  
Sodium Dodecylbenzene Sulfonate ◽  
Good Thermal Stability ◽  
Inductively Coupled ◽  
Dodecylbenzene Sulfonate

This paper investigated the preparation and characterization of the Zn-antibacterial White Carbon Black modified by electrolyte, surfactant, and organic solvent. The sol-gel method was used to prepare the White Carbon Black carrier. Zn2+ was selected to be the antibacterial ion, and Sodium nitrite (electrolyte), Sodium dodecylbenzene sulfonate (Surfactant), Ethanol (organic solvent) was selected to be the modifiers. They were synthesized on the white carbon black carrier. These as-synthesized modified antibacterial materials were characterized by inductively coupled plasma, particle size measurement instrument and enumeration tests (Escherichia coli as experimental bacterium). The result showed that the amount of antibacterial ions and bacteriostasis rate of modified Zn-antibacterial white carbon black are higher than those for the common Zn-antibacterial white carbon black. In addition, the particle sizes of modified samples can be extended down with a narrow size distribution. Other advantage of modified Zn-antibacterial white carbon black is good thermal stability.

Studies on Microcapsules. XII. Preparation and Characterization of Carboxylated Polyphthalamide Microcapsules

1971 ◽  
Vol 49 (22) ◽  
pp. 3623-3626 ◽  
Author(s):  
Yoshimichi Shigeri ◽  
Michiko Tomizawa ◽  
Kikuko Takahashi ◽  
Masumi Koishi ◽  
Tamotsu Kondo
Keyword(s):  
Amino Acids ◽  
Electric Field ◽  
Organic Solvent ◽  
Cation Binding ◽  
Interfacial Polycondensation ◽  
Polycondensation Reaction ◽  
Basic Amino Acids ◽  
Carboxylic Groups

Carboxylated polyphthalamide microcapsules were prepared by utilizing the interfacial polycondensation reaction between basic amino acids in water and p-phthaloyl dichloride in organic solvent. The yield of the microcapsules was found to be dependent on the concentration of emulsifier in the organic solvent and temperature. The microcapsules moved towards the anode in an electric field irrespective of the pH of the medium owing to the presence of carboxylic groups in the membranes. Cation binding experiments indicated an increasing order, Al3+ > Mg2+ > Cs+ > K+, NH4+, Na+ > Li+, for the binding of these cations to the microcapsules.

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