scholarly journals Synthesis and un-isotherm kinetic study of some ferrocene acids

2004 ◽  
Vol 2 (4) ◽  
pp. 553-562
Author(s):  
Daniela Apreutesei ◽  
Gabriela Lisa ◽  
Natalia Hurduc ◽  
Dan Scutaru

AbstractThe goal of this paper is to study thermal stability of some ferrocenes with acidic functional groups. Some other kinetic characteristics such as critical temperature and the rate constant corresponding to maximal degradation speed have been also evaluated. The type of functional units adjacent to the ferrocenyl unit determines thermal stability of ferrocene compounds. Groups with a powerful withdrawing effect determine a decreasing of the temperatures at which the material starts to lose weight. If a very long alkyl chain is connected to the ferrocene unit, a shielding effect in respect to the other carboxylic groups was observed, with an increase of the thermal stability.

1974 ◽  
Vol 20 (10) ◽  
pp. 1403-1409 ◽  
Author(s):  
B. G. Foster ◽  
Mary O. Hanna

Aeromonas proteolytica was grown for various time periods in nutrient broth, tryptic soy broth, a semisynthetic medium, and 1 and 5% peptone under different conditions involving temperature and in continuous shake and stationary flasks. The cell-free culture filtrates were tested for hemolytic, endopeptidase, and dermonecrotic activity and optimal growth conditions for their production were determined. The dermonecrotic activity and endopeptidase activity was found to be parallel in all tests, while hemolysin was independent of the other two. Studies on the thermal stability of the culture filtrate revealed that hemolysin and dermonecrotic and endopeptidase activity were destroyed at 70 °C for 30 min. Fractionation of the filtrate by Sephadex G-200 resolved three peaks at 280 nm. Peak I was inactive; peak II contained endopeptidase and dermonecrotic and hemolytic activity; peak III contained pigment and hemolysin. Evidence is presented that the endopeptidase and dermonecrotic substance found in the cell-free filtrates of A. proteolytica grown medium appear at the same time and thus may be the same entity.


2007 ◽  
Vol 561-565 ◽  
pp. 2399-2402
Author(s):  
Yoshihisa Kaneko ◽  
H. Sakakibara ◽  
Satoshi Hashimoto

Co/Cu and Ni/Cu multilayers fabricated by electroplating technique were annealed at various temperatures in order to investigate thermal stability of multilayered structures. Vickers hardness tests on the annealed Co/Cu and Ni/Cu multilayers were conducted at room temperature. It was recognized that after the annealing at 1023K the Co/Cu multilayer still maintained the hardness of as-deposited state. On the other hand, the hardness of Ni/Cu multilayer was almost identical to copper substrate after the annealing at 903K.


2007 ◽  
Vol 539-543 ◽  
pp. 3497-3502 ◽  
Author(s):  
J.P. Chu ◽  
C.H. Lin

Sputtered Cu films containing various insoluble substances, such as Cu(W2.3), Cu(Mo2.0), Cu(Nb0.4), Cu(C2.1) and Cu(W0.4C0.7), are examined in this study. These films are prepared by magnetron sputtering, followed by thermal annealing. The crystal structure, microstructure, SIMS depth-profiles, leakage current, and resistivity of the films are investigated. Good thermal stability of these Cu films is confirmed with focused ion beam, X-ray diffractometry, SIMS, and electrical property measurements. After annealing at 400°C, obvious drops in resistivity, to ~3.8 μ-cm, are seen for Cu(W) film, which is lower than the other films. An evaluation of the leakage current characteristic from the SiO2/Si metal-oxide-semiconductor (MOS) structure also demonstrates that Cu with dilute tungsten is more stable than the other films studied. These results further indicate that the Cu(W) film has more thermal stability than the Cu(Mo), Cu(Nb), Cu(C), Cu(WC) and pure Cu films. Therefore, the film is suitable for the future barrierless metallization.


2016 ◽  
Vol 4 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Léa Chancelier ◽  
Olivier Boyron ◽  
Thibaut Gutel ◽  
Catherine Santini

This work highlights the factors tuning the thermal stability of imidazolium-based ionic liquids (IL) associated to bis(trifluoromethanesulfonyl)imide anion [NTf2]. The decomposition temperatures (Td) were evaluated by thermogravimetric analyses (TGA) with optimized parameters to obtain reproducible Td. The impact of the alkyl chain length and of the presence of functional groups and unsaturations on Td were evaluated. The thermal behaviour was governed by Van der Waals interactions between alkyl chains, and by inter and intra coulombic interactions such as hydrogen bonds.


1985 ◽  
Vol 58 ◽  
Author(s):  
K. Aoki ◽  
K. Hiraga ◽  
T. Masumoto

ABSTRACTTi-Ni-Al alloys were rapidly quenched from a molten state by the melt spinning method. Three kinds of metastable phases, namely, amorphous,nonequilibrium and quasicrystalline phases are formed in these alloys. The amorphous phase is formed in the range of 35 to 70 at% Ti and 0 to 25 at% Al. The nonequilibrium phases are formed in the composition range of 25 to 33 at% Ti. On the other hand, fine quasicrystalline phases are distributed in the amorphous matrix of the Ti-rich alloys. Crystallization temperatures and the hardness of the amorphous alloys were also examined.


2014 ◽  
Vol 804 ◽  
pp. 271-274 ◽  
Author(s):  
Nguyen Hoang Viet ◽  
Nguyen Thi Hoang Oanh ◽  
Pham Ngoc Dieu Quynh ◽  
Tran Quoc Lap ◽  
Ji Soon Kim

Al-Fe-Y amorphous alloys of Al84Fe16, Al82Fe18 and Al82Fe16Y2 composition were prepared by mechanical alloying in a planetary ball mill P100. A nearly complete amorphization could be achieved for the Al84Fe16, Al82Fe18 and Al82Fe16Y2 powder alloys after 100h of milling at a rotational speed of 350 rpm in hexane medium. Differential scanning calorimetry (DSC) analyses revealed three-stage crystallization processes for Al82Fe18 and Al82Fe16Y2 alloys and four-stage crystallization processes for Al84Fe16 alloy, respectively. Taking into account the DSC data, the thermal stability increased in the order of Al84Fe16, Al82Fe18, and Al82Fe16Y2 composition. The Al82Fe16Y2 alloy exhibited a relatively better thermal stability than the other two alloys.


2006 ◽  
Vol 3 (4) ◽  
pp. 202-217 ◽  
Author(s):  
Reza Ansari ◽  
M. B. Keivani

In the current studies, polyaniline (PANi) was prepared both chemical and electrochemically in the presence of different bronsted acids from aqueous solutions. The effect of thermal treatment on electrical conductivity, and thermal stability of the PANi conducting polymers were investigated using 4-point probe and TGA techniques respectively. It was found that polymer prepared by CV method is more thermally stable than those prepared by the other electrochemical techniques. In this paper we have also reviewed some fundamental information about synthesis, general properties, diverse applications, thermal and environmental stability of polyaniline conducting polymers.


2000 ◽  
Vol 648 ◽  
Author(s):  
M. H. Juang ◽  
C. I. Ou-Yang ◽  
H. C. Cheng ◽  
C. T. Lin

AbstractEffects of phosphorus dopant on thin Pd and Pt silicide films on (100) Si substrates have been studied. As for the samples formed by implanting BF2 dopant into thin Pd films deposited on Si substrates and then annealing, the thermal stability of thin Pd2Si films can be improved relative to the control samples without dopant incorporation. The degree of improvement is affected by the fluorine concentration around the silicide/Si interface and thus the BF2 implant energy. On the other hand, as for the samples formed by implanting phosphorus dopant into thin Pd films and then annealing, both the thermal stability and the silicide conductivity of thin Pd2Si films can be significantly enhanced. The large improvements in the thermal stability and the silicide conductivity are nearly independent of the phosphorus implant energy, and which are primarily due to the formation of textured Pd2Si structures. In addition, the Pt silicides formed by implanting phosphorus dopant into thin Pt films and then annealing also show considerably improved thermal stability.


2013 ◽  
Vol 844 ◽  
pp. 217-220 ◽  
Author(s):  
Uraiwan Sookyung ◽  
Woothichai Thaijaroen ◽  
Norbert Vennemann ◽  
Charoen Nakason

Sodium-montmorillonite (Na-MMT) nanoclay was modified with different types of alkylamine organic modifier including primary and quaternary alkylamines. Influence types of alkylamine on properties of natural rubber/clay nanocomposites was investigated. It was found that organoclays caused improvement of mechanical properties of natural rubber, and accelerated vulcanization reaction with higher degree of crosslinking. In addition, organoclay modified with quaternary alkylamine showed significance cure reversion phenomenon which caused reduction of thermal stability. On the other hand, primary alkylamine modified nanoclay caused improvement of thermal stability of natural rubber. Moreover, stress relaxation was observed at the melting temperature of the modifying agent.


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