scholarly journals Adsorption of Oligomeric Peroxides on Aerosil and Magnesium Oxide and Their Behavior on the Water-Air Phases Interface

2021 ◽  
Vol 15 (1) ◽  
pp. 47-52
Author(s):  
Volodymyr Dutka ◽  
◽  
Nataliya Oshchapovska ◽  
Keyword(s):  
Thermal Degradation ◽  
Magnesium Oxide ◽  
Water Surface ◽  
Degradation Rate ◽  
Adsorption Process ◽  
Sebacic Acid ◽  
Conformational State ◽  
K Value ◽  
Oh Groups ◽  
Monomolecular Film

Oligomeric peroxide adsorption of sebacic acid on aerosil and magnesium oxide was studied. Adsorption process parameters were found. It is shown that the adsorption takes place through the hydrogen bonds formation between OH– groups of adsorbents surface and peroxide groups. The adsorption process suggests the behavior of peroxide compounds on the water-air phase’s interface. Monomolecular film formations on water surface for oligomeric peroxides were studied. It was found that calculated values of the area extrapolated to zero pressure (S0) depend on the solvent which was used to apply the peroxide in the phases interface. Oligomeric peroxide monolayers considered as condensation-type monolayers. Thermal decomposition of oligomeric peroxide and its di- and monoperoxide analogues was studied. It was shown that total constants of thermal degradation rate k for oligomeric peroxide are higher than those for di- and monoperoxide analogues. There is a correlation between S0 calculated values and the constants of thermal degradation rate for oligoperoxide. The less is S0 value the higher is k value. The conformational state of the macromolecule was preserved during transferring the oligomeric peroxide solution in an organic solvent to the phases interface that affects k values.

Thermal Degradation Rate and Kinetic Modeling of CO2-Loaded Amine Solvent Blends of 2-Amino-2-methyl-1-propanol and 1-Amino-2-propanol

2019 ◽  
Vol 59 (2) ◽  
pp. 685-692
Author(s):  
Naser S. Matin ◽  
Jesse Thompson ◽  
Keemia Abad ◽  
Saloni Bhatnagar ◽  
Kunlei Liu
Keyword(s):  
Thermal Degradation ◽  
Kinetic Modeling ◽  
Degradation Rate ◽  
Solvent Blends

scholarly journals Journal of Food Quality Thermal Degradation of Plum Anthocyanins: Comparison of Kinetics from Simple to Natural Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mihaela Turturică ◽  
Nicoleta Stănciuc ◽  
Claudia Mureșan ◽  
Gabriela Râpeanu ◽  
Constantin Croitoru
Keyword(s):  
Antioxidant Activity ◽  
Citric Acid ◽  
Thermal Degradation ◽  
Fluorescence Spectra ◽  
Degradation Rate ◽  
Natural Systems ◽  
Degradation Rate Constant ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The Stability

The stability of anthocyanin was assessed over a temperature range of 50–120°C in different simulated plum juices in order to compare the thermal behavior in the presence of certain compounds. The results were correlated with the antioxidant activity and intrinsic fluorescence spectra. The results suggested significant changes, especially at higher temperature; hence, increase in the fluorescence intensity and some bathochromic and hypsochromic shifts were observed. Anthocyanins in natural matrices presented the highest rate for degradation, followed by the anthocyanins in juices with sugars. Values of the activation energies were 42.40 ± 6.87 kJ/mol for the degradation in water, 40.70 ± 4.25 kJ/mol for the juices with citric acid, 23.03 ± 3.53 kJ/mol for the juices containing sugars, 35.99 ± 3.60 kJ/mol for simulated juices with mixture, and 14.19 ± 2.39 kJ/mol for natural juices. A protective effect of sugars was evidenced, whereas in natural matrices, the degradation rate constant showed lower temperature dependence.

Functionalizingλ-AlOOH Surface with Silanol -- an Ab-initio Study

2007 ◽  
Vol 1000 ◽  
Author(s):  
Petri Lehtinen ◽  
Guido Grundmeier ◽  
Alexander Blumenau
Keyword(s):  
Ab Initio ◽  
Adsorption Process ◽  
Water Environment ◽  
Water Molecules ◽  
Organic Film ◽  
Oh Groups ◽  
Inorganic Films ◽  
Adsorption Of Water ◽  
Zinc Coatings ◽  
Insight Into

AbstractOn HDG-steel, zinc coatings are used for corrosion protection. Part of that coating is composed of aluminum and this leads to the creation of aluminum oxide film on the coating with thicknesses of 2-3 nanometers. This layer is an amorphous boehmite film.Boehmite, or λ-AlOOH, has several application areas, but for us the interesting ones are related to an area where the surface is functionalized, for example in a way that the organic and inorganic films can be “glued” together. A good candidate for the interface is the silanol molecule. The idea is that the OH-groups of the molecule attach on the inorganic film and the methyl groups on the organic film and hence promote adhesion between the two.We present theoretical ab-initio results of adsorption of water and silanol molecules on the λ AlOOH (0001)-surface. Since the experimental adsorption of the silanol on the boehmite surface is done in water environment, the adsorption process is therefore a competing process. We will present some result of adsorption of silanol in the presence of water molecules to get an insight into this process.

The Effect of Ar/H2 Plasma Pretreatments on Porous K=2.0 Dielectrics for Pore Sealing by Self-Assembled Monolayers Deposition

2012 ◽  
Vol 195 ◽  
pp. 146-149 ◽  
Author(s):  
Y. Sun ◽  
J. Swerts ◽  
P. Verdonck ◽  
A. Maheshwari ◽  
J.L. Prado ◽  
...  
Keyword(s):  
Plasma Temperature ◽  
Self Assembled Monolayers ◽  
Hydroxyl Groups ◽  
K Value ◽  
Oh Groups ◽  
Surface Hydroxyl ◽  
Pore Sealing ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Low K

Self-assembled monolayers (SAMs) deposition is being recently explored to help sealing the pores of a k=2.0 material. In order to enable a covalent chemical low-k surface functionalization by SAMs, a hydroxyl groups density as high as 1 to 2.5 OH groups/nm2 is required. This surface modification must be carefully controlled to confine the k below 10%. In this paper, the effects of plasma temperature, time and power on the SAMs deposition and plasma-induced damage are investigated. The main findings are that there is always a trade-off between surface hydroxyl groups density and bulk damage. A thick modified layer allows the SAM molecules to penetrate inside the pores which results in a decreased porosity and an increased k value with respect to correspondent plasma-treated pristine substrates.

scholarly journals Thermal Degradation Kinetics of Capsaicin on Blanching-Brine-Calcium Pretreatment Red Chili Pepper Drying

2018 ◽  
Vol 13 (2) ◽  
pp. 365 ◽  
Author(s):  
Uma Fadzilia Arifin ◽  
Mohamad Djaeni
Keyword(s):  
Thermal Degradation ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Bioactive Compound ◽  
Chili Pepper ◽  
Thermal Degradation Kinetics ◽  
Drying Process ◽  
Local Farmer ◽  
Layer Chromatography ◽  
Kinetics Of

Post-harvest red chili pepper (Capsicum frutescens) has highly capsaicin as bioactive compound and moisture content. However, capsaicin is the responsible bioactive compound in chili for hot sensation that easy to degrade by partial oxidation caused introduction of heat in drying process. The objective of this research was to investigate kinetics of capsaicin degradation in the drying process under blanching-brine-calcium pretreatment and various temperatures. For this purposes, chili provided local farmer was pretreated using blanching-brine-calcium pretreatment. Afterward, they were dried at 40, 50, 60, and 70 oC for 8 hours. Degradation of capsaicin content was observed every 2 hours using Thin Layer Chromatography (TLC). Results showed kinetics of capsaicin degradation was categorized as second order reaction. At the same temperature and time, capsaicin retention of blanching-brine-calcium pretreated chili has highest value. The temperature dependence of the capsaicin degradation rate was analyzed using Arrhenius correlation. The activation energy for degradation rate of capsaicin during drying was around 45.10367 kJ/mol.K. It indicated the degradation rate increased as well as increased the temperature at the same time. Copyright © 2018 BCREC Group. All rights reservedReceived: 26th October 2017; Revised: 14th February 2018; Accepted: 18th February 2018; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Arifin, U.F., Djaeni, M. (2018). Thermal Degradation Kinetics of Capsaicin on Blanching-Brine-Calcium Pretreatment Red Chili Pepper Drying. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 365-372 (doi:10.9767/bcrec.13.2.1660.365-372) 

Study on Thermal Degradation and Kinetic of Microencapsulated Red Phosphorus (MRP)/High Density Polyethylene (HDPE) Composite

2020 ◽  
Vol 842 ◽  
pp. 98-104
Author(s):  
Jia Li ◽  
Hui Wang ◽  
Zhong Han Li ◽  
Ting Ting Zhao ◽  
Tian Tian Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
High Density Polyethylene ◽  
Degradation Rate ◽  
Degradation Mechanism ◽  
High Density ◽  
Red Phosphorus ◽  
Heating Rates ◽  
Ikp Method

Thermal degradation of the composite constituted by high density polyethylene (HDPE) and microencapsulated red phosphorus (MRP) were studied using thermogravimetric (TG) data obtained at different heating rates. The kinetic models and parameters of the thermal degradation of MRP/HDPE composite were evaluated by FWO, KAS and IKP method. It indicates that the activation energy E of 4 % MRP/HDPE composite is higher than HDPE for three methods. MRP could improve the thermal stability and slow down the thermal degradation of HDPE. With adding MRP, the degradation mechanism of HDPE is changed and the degradation rate decreases.

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