TEMPO-mediated oxidation has been reported to effectively convert C6 primary hydroxyl groups to carboxyl groups for better water-solubility. However, the pH decreases continuously during the oxidation process, and it is therefore difficult to maintain the stability of the reaction. The control of pH at a constant level throughout the oxidation process is a complicated task. The applicability of...

The method was that of Pisano et al. (1962) as described by Sandler and Ruthven (1963). 4-Hydroxy-3-methoxymandelic acid was obtained from Calbiochem (A Grade) and ethyl acetate A.R. (Analar) was used. For the purpose of this investigation, an acidified aqueous solution of V.M.A., saturated with sodium chloride, was extracted with ethyl acetate (30 ml.) which had been treated in various ways be...

In the paper the results of experimental studies on the sedimentation process of barium carbonate (of mean particles diameter of 25 [μm]) in aqueous solutions of tetradecyltrimethylammonium bromide, have been presented. As the additives assisting in micellar association the sodium bromide and sodium salicylate, have been used. The sedimentation tests were carried out in the transparent cylinder...

Vanadium is distributed widely and scarcely (150 ppm) on the earth. Its major applications are in steelmaking, dye-production and catalyst-fabrication industries. With the ever-increasing demand for this metal, secondary resource-exploitation of such waste materials as spent catalysts is recommended. Many reactions are involved in vanadium-extraction from these resources. Since roasting in comp...