TY - JOUR
AU - Sawaki, Yasuhiko
AB - The catalytic activities of some inorganic compounds for the hydrogen peroxide oxidation of thiodiglycol (TDG) have been examined in aqueous media at 25°C and at pH 4.7. It has been found that the order of catalytic activities was: Na2MoO4, Na2WO4>>H2SeO3>NH4VO3, Na2TeO4, UO2(OAc)2, Cu(OAc)2. The rates of oxidation using all these catalysts, except sodium molybdate, may be expressed as v=k2[H2O2] [TDG].The kinetics of this reaction has been studied in detail, especially with the sodium molybdate (SM) catalyst, by means of iodometry. The oxidation in the range [H2O2]>2[SM] follows the pseudo-first-order kinetics : v=k1c[SM] [TDG]. The rate at pH below 2 is several times faster than that at pH 3∼6, the energies of the activation at pH’s below 2 and at 3∼6 being 9.21 and 11.2 kcal. mol−1 respectively. The oxidation in the range of [H2O2]<2[SM] follows the second-order kinetics : v=k2′[Active oxygen] [TDG]. The values of k2′ were identical with the second-order rate constants obtained in the oxidation of thiodiglycol by yellow sodium peroxymolybdate. It is probable that dihydroperoxymolybdate, HMoO6−, produced rapidly from Na2MoO4 and hydrogen peroxide, oxidizes thiodiglycol The increase in the rate with a decreasing pH may be due to the transformation of HMoO6− to more active H2MoO6, since the Na2MO4-hydrogen peroxide system gave two different ultraviolet absorption maxima corresponding to HMoO6− and H2MoO6 at pH 4.7 and 0.8 respectively.
TI - Kinetics of the Catalytic Hydrogen Peroxide Oxidation of Thiodiglycol in Aqueous Solutions
JO - Bulletin of the Chemical Society of Japan
DO - 10.1246/bcsj.36.1453
DA - 2006-03-27
UR - https://www.deepdyve.com/lp/oxford-university-press/kinetics-of-the-catalytic-hydrogen-peroxide-oxidation-of-thiodiglycol-a2UPRnv5GW
SP - 1453
EP - 1459
VL - 36
IS - 11
DP - DeepDyve
ER -