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Department of Chemistry, University of Rajasthan, Jaipur-302 004, Rajasthan, India E-mail : guptaks 14@rediffmail.com Govt. College, Dausa. Rajasthan, India Manuscript received 7 August 2008, revised 16 January 2009, accepted 11February 2009 The most important feature of this study of the oxidation of nicotinic acid (Nic) and isonicotlnlc acid (lnic) by permanganate in acidic medium Is the complete solution of the rate laws (A) for Nic and (8) for lnic by varying [H+] over an extended concentration range. -d[MnO4-]/dt = {k0K1 [H+] + k K1 K2 [H+]2 + k3 K1 K1 K3 [H+]3}[MnO4-]1[Nic]0/{1+ K1 [H+] + K1 K2 [H+]2} -d[MnO4-]/dt = {k K2[H+] + k3 K2 K3 [H+]2}[MnO4-]t[lnie]/(1+ K2[H+]} The relationships of the rate parameters and their values are as follows : K1(NC5H4COO- + H+⇔ HN+C5H4COO- [B]), 1.78 x 104 (30") (Nic); K1 (HN+C5H4CO-[B] + H+⇔ HN+C5H4COOH[C]), 46.2 (30°) (Nic), 33.6 (40°) (lnie); k0 ([B) + MnO4- → products), 1.56 x 10-3 L mol-1S-1 (30°) (Nic); k ([C) + MnO4-→ products), 1.64 x 10-1 (30°) (Nic), 1.68 x 10-1 L mol-1 s-1(40°) (lnic) and k3 K3 ([C) + HMnO4 →. products), 2.02 x 10-1 (30°) (Nic), 3.2 x 10-3 L2mo1-1 s-1(40°) (lnic). The reactivity of Nic was greater than that of lnic. |
