scholarly journals Effect of Temperature on the Reaction of 2-(N-acetylamine)-3-(3,5-di-<i>tert</i>-butyl-4-hydroxyphenyl)-propionic Acid with Oxygen in an Alkaline Condition

2015 ◽  
Vol 05 (03) ◽  
pp. 262-269
Author(s):  
A. A. Volodkin ◽  
G. E. Zaikov ◽  
L. N. Kurkovskaja ◽  
S. M. Lomakin ◽  
I. M. Levina ◽  
...  
Keyword(s):  
Propionic Acid ◽  
Effect Of Temperature ◽  
Alkaline Condition

Optimization of Esterification of Propionic Acid with Ethanol Catalyzed by Solid Acid Catalysts using Response Surface Methodology (RSM): A Kinetic Approach

2017 ◽  
Vol 15 (4) ◽  
Author(s):  
Anurag Tiwari ◽  
Amit Keshav ◽  
Shubhankar Bhowmick
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Propionic Acid ◽  
Rice Husk ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Catalyst Loading ◽  
Dowex 50Wx8

Abstract The esterification of propionic acid and ethanol using waste material as catalyst is emerging and a new technology. In this section a carbon based solid acid catalyst was prepared in laboratory by sulfonating waste rice husk char using concentrated H2SO4 and was compared with a commercial catalyst Dowex 50Wx8-400. Characterization analysis of the catalyst was performed using scaning electron microscope (SEM), EDEX and FTIR. Various reaction parameters such as effect of temperature, effect of the molar ratio of ethanol to propionic acid and effect of catalyst loading were investigated. Reusability of catalyst was also performed 4 cycles for efficiency of prepared catalyst. The activation energy (Ea) of esterification was found to be 39.782 kJ mol−1 using rice husk catalyst and 65.306 kJ mol–1 for Dowex 50wx8-400 catalyst. Response surface methodology (RSM) was applied to find the optimal operating conditions in order to maximize the ethyl propionate conversion.

Effects of Temperature on Deposition Rate of Supersaturated Silicic Acid on Ca-Type Bentonite

2016 ◽  
Author(s):  
Tsuyoshi Sasagawa ◽  
Taiji Chida ◽  
Yuichi Niibori
Keyword(s):  
Deposition Rate ◽  
Silicic Acid ◽  
Cementitious Materials ◽  
Effect Of Temperature ◽  
Alkaline Condition ◽  
High Concentration ◽  
Flow Paths ◽  
Effects Of Temperature ◽  
Materials Used ◽  
High Level

For the disposal system of high-level radioactive waste in Japan, Na-type bentonite is used as one of backfilling and buffer materials for preventing the migration of groundwater and radionuclide. However, the alteration to Ca-type bentonite will cause the degradation of the barrier performance. On the other hand, silicate minerals around the repository dissolve under the high alkaline condition of groundwater (about pH 13) altered by alkaline components leaching from cementitious materials used for the construction of the repository. Such high-concentration silicic acid becomes supersaturated with the decrease in pH by mixing with natural downstream groundwater (pH 8) because of the change in the solubility of silicic acid. So far, the authors have examined the deposition rates of supersaturated silicic acid on Ca-type bentonite under the condition of room temperature, showing the clogging effect of flow-paths with the deposition. However, the dynamic behaviors of silicic acid are much sensitive to temperature change. Therefore, the present study focuses on the effect of temperature on the deposition rate of silicic acid on Ca-type bentonite. As a result, in the range up to 323 K, the deposition of supersaturated silicic acid on Ca-type bentonite was promoted with the increase in temperature. This suggests that the deposition of silicic acid will clog the flow-paths in Ca-type bentonite in this temperature range.

Formation of HAAs and THMs in the Water Treatment and Distribution System of Macau

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
H. Wong ◽  
K.M. Mok
Keyword(s):  
Water Treatment ◽  
Distribution System ◽  
Mass Concentration ◽  
Treatment Process ◽  
Distribution Network ◽  
Treatment Plant ◽  
Effect Of Temperature ◽  
Alkaline Condition ◽  
Treated Water ◽  
Formation Behavior

This study investigated the formation behavior of two CDBPs, namely THMs and HAAs, in a treatment plant and the distribution network of Macau. Concentrations of the four species of THMs and the six species of HAAs were monitored at different stages of the treatment process and at two separate points in the distribution network during February 2006 to January 2007. The results show that the mass concentration of THMs was generally higher than that of HAAs in treated water with a ratio ranging from around 1:1 to 2:1. The results suggested that two steps, pre-chlorination and coagulation, performed in the treatment process influenced the formation of CDBPs in the plant. The CDBPs formation was found to continue in the distribution system with the concentration of THMs increasing faster. The effect of temperature on the formation of HAAs was found to be more significant than on that of THMs. In an alkaline condition, both THMs and dihaloacetic acids were easier to form but the concentration of some trihaloacetic acid decreased.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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