Mesoporous carbon black as a metal-free electrocatalyst for highly effective determination of chromium(VI)

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

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Dissociation of imino proton(s) of a highly water-soluble metal-free phthalocyanine and determination of its pKa value in water

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424613500235 ◽

2013 ◽

Vol 17 (06n07) ◽

pp. 447-453 ◽

Cited By ~ 2

Author(s):

Hiroaki Isago ◽

Harumi Fujita

Keyword(s):

Aqueous Media ◽

Thermal Reaction ◽

Water Soluble ◽

Acid Dissociation ◽

Acid Dissociation Constant ◽

Metal Free ◽

Imino Proton ◽

Pka Value ◽

Triton X

Dissociation of imino proton(s) in the cavity of the macrocycle of a highly water-soluble, metal-free phthalocyanine ( H 2( H 4 tsppc ); where H 4 tsppc denotes tetrakis{(2′,6′-dimethyl-4′-sulfonic acid)phenoxy}phthalocyaninate) in ethanolic and aqueous solutions has spectrophotometrically been investigated. The spectral changes associated with reaction with NaOH have been found to involve one-proton transfer process in aqueous media while two-protons process in ethanolic media. The acid-dissociation constant of the first imino proton in water (in the presence of Triton X-100) has been determined to be 12.5 ± 0.2 (as pKa) at 25 °C. The doubly deprotonated species in EtOH has been easily converted to its corresponding cobalt(II) derivative by thermal reaction with anhydrous CoCl 2.

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