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Imae, Toyoko
- The Effect of Degree of Protonation on the Phase Diagrams of Alkyldimethylamine Oxides
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Authors
Affiliations
1 Department of Chemistry, Nagoya University, Nagoya 464, JP
1 Department of Chemistry, Nagoya University, Nagoya 464, JP
Source
Journal of Surface Science and Technology, Vol 4, No 1 (1988), Pagination: 67-80Abstract
For aqueous NaCl solutions of alkyldimethylamine oxides (Cn-DAO, n = 12,14,16), the potentiometric titration curves and the phase diagrams have been drawn as a function of the degree of protonation, α, surfactant and NaCl concentrations, C, and the temperature, T. The logarithm of apparent dissociation constant changes complicatedly with an increase in the degree of protonation, being related to the variations in the content of monomeric molecules and micelles and in micelle aggregation number. The T-α-C, diagrams for aqueous NaCl solutions of CnDAO with a surfactant concentration of 0.3 x l0-2 g cm-3 exhibit the liquid-liquid phase separation region above the Krafft temperature and at high NaCl concentrations. The consolute phase boundary spreads parabolically on both sides of α -0.5, slightly dependent on the temperature. The critical value of lower consolute NaCl concentration is 1.4 M for C14DAO. 0.32 M for C14DAO and 0.08 M for C16DAO in the T-α-c diagram for 0.37 M NaCl solutions of C14DAO, two liquid phase region is spheroidal in shape with ranges of T = 25-75°C. α = 0.38-0.60 and c = 0.05-1.67 × 10-4 g cm-3. The effect of the degree of protonation on the liquid-liquid phase separation is discussed in connection with the solute-solvent and solute-solute interactions and the micellar growth.Keywords
Alkyldimethylamine Oxide, Phase Diagram, Protonation.
- Dendrimer Mediated In Situ Preparation of Size-Controlled Platinum-Nickel Alloy Nanoparticles on Carbon Nanotubes as Electrocatalysts for Methanol Oxidation
Abstract Views :286 |
PDF Views:2
Authors
Affiliations
1 Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei - 10607, TW
2 Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei - 10607, TW
1 Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei - 10607, TW
2 Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei - 10607, TW
Source
Journal of Surface Science and Technology, Vol 31, No 1-2 (2015), Pagination: 51-57Abstract
PtxNiy alloy nanoparticles with different compositions were prepared on Carbon Nanotube (CNT) surfaces in the presence of amine-terminated poly(amido amine) dendrimer as a scaffold. PtxNiy alloys with an average diameter of 2–3 nm were uniformly deposited on dendrimer bound on CNT. The formation of the PtxNiy alloys and the presence of Pt(0), Ni(0), Ni(OH)2 and NiOOH were revealed from X-ray diffraction and X-ray photoelectron spectroscopic results. The total metal content in the PtxNiy alloys increased with increasing the supplied Ni precursor, and the addition of Ni to Pt could lead the alloy formation with high thermal stability. It should be noted that the bimetallic nanoparticles with Ni up to 20 wt% showed efficient catalytic activity for methanol oxidation in proportion to Pt catalyst. This study demonstrates the promising alternative for the high demand of Pt in the cathode catalysts of direct methanol fuel cells.Keywords
Carbon Nanotube, Dendrimer, Electrocatalyst, Methanol Oxidation, Platinum-Nickel AlloyReferences
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