2.
Comparative Study of Ruthenium (III) Catalyzed Oxidation of D(+)
Xylose Both in Acidic and Alkaline Media
Ashish
Kumar*
Chemistry
Department, Lovely Professional University, Phagwara – Punjab,
India.
E-mail:
ashish.kumar@lpu.co.in
/ chemvidhi@gmail.com
Abstract.
Kinetic investigation on ruthenium(III) catalyzed oxidation of
xylose by a solution of potassium bromate in the presence of
mercuric acetate as a scavenger for Br- ion have been
carried out in the temperature range 300 – 450C
in both acidic and alkaline medium. First order kinetics in the
lower KBrO3 concentration range tended to zero order
at higher concentration was observed in acidic medium but shows
first order dependence in alkaline medium. The order of reaction
with respect to substrate is zero but the order with respect to
Ru(III) is one in both alkaline and acidic medium. Increase in
[Cl-] shows negligible effect while increase in [H+]
shows negative effect in acidic medium but in alkaline medium
Increase in [Cl-] shows positive effect whereas
increase in [OH-] shows negative effect. Negligible effect of
mercuric acetate and ionic strength of the medium was observed
in both media. D2O have an insignificant effect on
the reaction rate. A suitable mechanism in conformity with the
kinetic observations has been proposed in both alkaline and
acidic medium and intermediates have been studied for
conformation.
KEY WORDS: alkaline medium; acidic
medium; kinetics; oxidation; potassium bromate; Ru(III)
catalyzed; xylose.
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