K Pitchumani
Articles written in Journal of Chemical Sciences
Volume 104 Issue 1 February 1992 pp 67-76 Physical and Theoretical
Kinetics and mechanism of oxidation of N-substituted phenothiazines by chromium(VI)
K Pitchumani V Subramanian P P Jegatheesan C Srinivasan
The kinetics of oxidation of N-acetylphenothiazine (NAPT) by Cr(VI) in 80% acetic acid-20% water (v/v) mixture is first-order each in [NAPT] and [Cr(VI)]. The reaction is catalysed by added acid with a third-order dependence in [HCIO4], Increase in polarity of the solvent medium decreases the rate. The oxidation is insensitive to variations in ionic strength as well as added acrylamide. Oxidations of phenothiazine (PT) and N-methylphenothiazine (NMPT) under similar conditions are found to be very fast. However kinetic investigations with NMPT in an acetic acid-sodium acetate buffer show first-order dependence each in [NMPT] and [Cr(VI)] and a fractional-order dependence in [H+] in the pH range 1.80-3.09. Increase in polarity of the medium increases the rate. In both the cases, the corresponding sulphoxides are identified as oxidation products. Based on the kinetic results, mechanisms for oxidations are proposed.
Volume 104 Issue 6 December 1992 pp 762-790
J Basu K K Rohatgi-Mukherjee S Chatterjee S Sarkar S N Bhattacharyya G K Dasmahapatra Thomas Wolff Gunther Von Bunau S N Dhawan Dipankar Sen Subhash Ch Bera S C Gupta N S Yadav Manabendra Sahu Manjubikash Saha V Masilamani D Sastikumar Pradipta Kumar Behera Ashok Kumar Mishra S Muthusamy V T Ramakrishnan P Ramamurthy S Sampath R Narayan M C Durai Manickam C Srinivasan K Pitchumani M Roja S Rajagopal Reba Ray Samaresh Mukherjee A Samanta E Natarajan S Selvaraj P Natarajan S S Talwar K Viswanathan P Natarajan Aruna Dhathathreyan K S Dhathathreyan Basanti Biswal Pill-Soon Song S Das M Muneer A Haridas V B Manilal R Jayakumar T Ramasami M Julliard M Chanon P N Joshi U C Biswal C L Joshy E Purushothaman Bhaskar G Maiya S Ganesan B Nagarajan V Narayanan Prasanna Mohanty V Shubin S D S Murthy N V Karapetyan R Ramaraj K V Gobi V Gomathi Sankareswari S Ranganayaki K Bahadur Sajal Kumar H R Sonawane D G Kulkarni N R Ayyangar N Sukumar T V Venkitachalam A S Rao S I Ali Harpal Kaur V Anbalagan T S Srivastava Awadhesh Kumar P K Chowdhury K V S Rama Rao J P Mittal N Balasubramanian S Balasubramanian G B Dutt S Doraiswamy Bidyut Kumar Manna K K Rohatgi-Mukherjee A Chandra B Bagchi S Arunachalam J R Devadason T Dhanasekaran K Joseph Prabahar Lizamma Mathew V Ramakrishnan J Rajaram V R S Rao P Narayanan V N Sivasankara Pillai K I Priyadarsini T Rajendran M Palaniandavar M Kaneko A Kira M S Sidhu Arti Chopra Barinder Gill Thomas Baby V P N Nampoori
Volume 115 Issue 2 April 2003 pp 113-121
Regioselective nitration of aromatic substrates in zeolite cages
T Esakkidurai M Kumarraja K Pitchumani
Phenol is nitrated regioselectively by fuming nitric acid inside the cages of faujasite zeolites (dependent on the loading level) and a remarkable ortho-selectivity is observed in solid state nitration. Toluene and chlorobenzene also containing ortho-/para-orienting substituents, undergo faster nitration, though the regioselectivity is less significant in zeolite media. The results are explained on the basis of diffusion and binding of phenol inside zeolite, which facilitate regioselectivity (and which is absent in toluene and chlorobenzene). Other advantages of employing zeolites as media for mild and selective nitration are also highlighted.
Volume 115 Issue 4 August 2003 pp 273-280
Regioselective photoamination of 4-nitroveratrole upon cyclodextrin complexation
M C Durai Manickam K Pitchumani C Srinivasan
Photoamination of 4-nitroveratrole in cyclodextrins with the nucleophiles ammonia, methylamine and hexylamine provides a new route to regioselectivity. This method gives a displaced product para to the nitro group as the predominant product, in contrast to the solution reaction wherein the meta-displaced product predominates. This is due to the change in the mechanistic shift from
Volume 135, 2023
All articles
Continuous Article Publishing mode
Click here for Editorial Note on CAP Mode
© 2022-2023 Indian Academy of Sciences, Bengaluru.