Reference

New Techniques for Following the Oxidation of Sodium Sulfite in Mass-Transfer Studies

New Techniques for Following the Oxidation of Sodium Sulfite in Mass-Transfer Studies.Some chemicals with cas registry numbers like 7646-79-9 and 10124-43-3 are also used. Lewis, Andrew C.; Roberts, David J. (Inorganic and Materials Chemistry, Department of Chemistry, Bristol University, Bristol, UK). Industrial & Engineering Chemistry Research, 44(1), 183-185 (English) 2005 American Chemical Society. CODEN: IECRED. ISSN: 0888-5885. DOCUMENT TYPE: Journal CA Section: 48 (Unit Operations and Processes) Computer modeling of mass transfer frequently requires empirical validation. Improvements in the empirical chem. method of the catalytic oxidn. of sodium sulfite are presented. The oxidn. by oxygen was followed by monitoring the change in UV absorption at a wavelength of 260 nm. Liq. was pumped from the reaction vessel, a stirred cell, into a 0.5-mL quartz flow cell inside a UV absorption spectrometer. Different catalysts were investigated for controlling the reaction rate. Cobalt sulfate and cobalt chloride were both successfully used in the anal. The real-time anal. of the oxidn. of sodium sulfite did not require pH stabilization and makes this procedure superior to the std. iodometric titrn. In addn., mass-transfer expts. can be miniaturized without loss of accuracy. .

Synthetic optimization of Li[Ni1/3Co1/3Mn1/3]O2 via co-precipitation

Synthetic optimization of Li[Ni1/3Co1/3Mn1/3]O2 via co-precipitation. Lee, M.-H.; Kang, Y.-J.; Myung, S.-T.; Sun, Y.-K. (Department of Chemical Engineering, Center for Information and Communication Materials, Hanyang University, Seoul 133-791, S. Korea). Electrochimica Acta, 50(4), 939-948 (English) 2004 Elsevier B.V.Some commonly used reagents like 7786-81-4 and 10124-43-3 are used in this experiment. CODEN: ELCAAV. ISSN: 0013-4686. DOCUMENT TYPE: Journal CA Section: 52 (Electrochemical, Radiational, and Thermal Energy Technology) Li[Ni1/3Co1/3Mn1/3]O2 powders were synthesized from co-pptd. spherical metal hydroxide, (Ni1/3Co1/3Mn1/3)(OH)2. The prepn. of metal hydroxide was significantly dependent on synthetic conditions, such as pH, amt. of chelating agent, stirring speed, etc. The optimized condition resulted in (Ni1/3Co1/3Mn1/3)(OH)2, of which the particle size distribution was uniform and the particle shape was spherical, as obsd. by SEM. Calcination of the uniform metal hydroxide with LiOH at higher temp. led to a well-ordered layer-structured Li[Ni1/3Co1/3Mn1/3]O2, as confirmed by Rietveld refinement of X-ray diffraction pattern. Due to the homogeneity of the metal hydroxide, (Ni1/3Co1/3Mn1/3)(OH)2, the final product, Li[Ni1/3Co1/3Mn1/3]O2, was also significantly uniform, i.e., the av. particle size was of ~10 mm in diam. and the distribution was relatively narrow. As a result, the corresponding tap d. was also high approx. 2.39 g/cm3, of which the value is comparable to that of commercialized LiCoO2. In the voltage range of 2.8-4.3, 2.8-4.4, and 2.8-4.5 V, the discharge capacities of Li[Ni1/3Co1/3Mn1/3]O2 electrode were 159, 168, and 177 mAh g-1, resp. For elevated temp. operation (55°), the resulted capacity was of ~168 mAh/g with an excellent cyclability. .