Effect of pressures to 3 kbar on the electrical conductivity of tetramethyl-ammonium bromide and hydrobromic acid in propan-1-ol and propan-2-ol

1976 ◽  
Vol 29 (2) ◽  
pp. 249 ◽  
Author(s):  
JF Cukurins ◽  
W Strauss

The conductances of tetramethylammonium bromide and hydrogen bromide have been measured in propan-1- and -2-ol at 25�C to pressures of 3 kbar. The increase in pressure has an almost identical effect on the excess proton conductance in both solvents, approximately doubling this to 1.5 kbar, after which it remains approximately constant.

Fractals ◽  
2011 ◽  
Vol 19 (03) ◽  
pp. 317-328 ◽  
Author(s):  
ISHWAR DAS ◽  
NAMITA R. AGRAWAL ◽  
RINKI CHOUDHARY ◽  
SANJEEV KUMAR GUPTA

Fractal growth patterns of polyaniline were developed during electropolymerization of aniline using the surfactants sodium dodecyl sulphate (NaDS) and NaDS containing cetyl trimethyl ammonium bromide (CTAB). Growth kinetics was studied and electric potential oscillations were monitored as a function of time. On addition of CTAB polymer growth was inhibited due to coordination of CTAB with the growing polyaniline chain. The average particle size of the polymer aggregate obtained from aniline- NaDS-H2O system was ~150 nm as evident by Transmission Electron Microscopy (TEM) results. Polymer aggregates were characterized by electrical conductivity measurements, X-ray diffraction (XRD) and Thermogravimetric (TG) studies. An interaction between NaDS and aniline was observed in the absence of electric field as evident by (i) electrical conductivity of aqueous solution of NaDS in the absence and presence of aniline, and (ii) their crystallization patterns on microslides. A mechanism for the development of fractal patterns and electrical potential oscillations is proposed on the basis of diffusion limited aggregation process.


1988 ◽  
Vol 135 ◽  
Author(s):  
R.P. Singh ◽  
P.N. Gupta ◽  
S.L. Agrawal ◽  
U.P. Singh

AbstractProton conduction in polymer composites of PVA+H3PO4 AND PVA+H2SO4 have been investigated. The films protonated by H3PO4 show protonic conductivity between 10−6to 10−3ohm−1cm−1 depending upon the relative ratios and temperature. H2SO4 protonated PVA films also show proton conductance of almost similar magnitude. The ionic transference number has been estimated to be 0.95 for H3PO4 protonated PVA film of ratio 70:30. The frequency and temperature dependence of electrical conductivity has also been carried out. These polymer films have been used to fabricate an electrochromic cell. The colorationtime determined from response time measurement for the system “SnO2|Glass|WO3 film|PVA film|SnO2 Glass” is 2.6 sec for H3PO4 doped films and 6 seconds for H2SO4 doped films.


1980 ◽  
Vol 101 (1) ◽  
pp. 423-429 ◽  
Author(s):  
B. E. Taylor ◽  
A. L. Laskar

Author(s):  
Fatima A. Mustafayeva ◽  
Najaf T. Kakhramanov

It is known that the antipyrenes, biological active substances (antitumor, antibacterial, antifungal, antiviral), pharmacological preparations on the basis of bromine-containing aromatic compounds are widely used in the industry. Considering this and increased demand for these substances the purpose of this work was to summarize and systematize the accumulated knowledge in this area. The article presents methods and reagent systems used in the bromination of aromatic amines. There have been described the bromination of aromatic amines with hydrogen bromide, sodium bromide, potassium bromide, ammonium bromide, copper (II) bromide, N-bromosuccinimide, N-bromosaccharin, polymer-supported halogenation agents, and difference of these methods from the point of view of the used oxidizer, the medium and the solvent, the catalyst, the regioselectivity, the quantity of bromine atoms in the obtained product. The influence of solvents, catalysts, the nature (electron-donor or electron-acceptor) and position (ortho-, meta-, para-) of the substituents in the aromatic ring, reaction conditions, molar ratio of the reagents, reaction temperature and carrying out time of bromination reaction of aromatic amines has been shown. The bromination reactions courses of aromatic amines in different solvents, in solvent free conditions, in solid states has been described. The bromination of aromatic amines under thermal, microwave, ultraviolet radiation conditions has been studied. In the paper the regioselective monobromination and also obtaining of di-, tri- bromo derivatives of aromatic amines has been shown. Taking into account today's priority to environmentally safe methods of bromination of aromatic amines they have been also mentioned. Given the above, in our opinion, the information presented in this article will help to optimize the production of bromo derivatives of aromatic amines used in industry, technics and technology.


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