Fe-polyaniline composite nanofiber catalyst for chemoselective hydrolysis of oxime

Sanjit Kumar Mahato; Madhumita Bhaumik; Arun Maji; Abhijit Dutta; Debabrata Maiti; Arjun Maity

doi:10.1016/j.jcis.2017.11.059

Fe-polyaniline composite nanofiber catalyst for chemoselective hydrolysis of oxime

J Colloid Interface Sci. 2018 Mar 1:513:592-601. doi: 10.1016/j.jcis.2017.11.059. Epub 2017 Nov 21.

Authors

Sanjit Kumar Mahato¹, Madhumita Bhaumik², Arun Maji³, Abhijit Dutta⁴, Debabrata Maiti⁵, Arjun Maity⁶

Affiliations

¹ Department of Civil and Chemical Engineering, University of South Africa (UNISA), PO Box 392, Pretoria 0003, South Africa.
² Department of Applied Chemistry, University of Johannesburg, Johannesburg, South Africa.
³ Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India.
⁴ Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
⁵ Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India. Electronic address: dmaiti@iitb.ac.in.
⁶ Department of Civil and Chemical Engineering, University of South Africa (UNISA), PO Box 392, Pretoria 0003, South Africa; Department of Applied Chemistry, University of Johannesburg, Johannesburg, South Africa; National Centre for Nanostructured Materials, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa. Electronic address: amaity@csir.co.za.

PMID: 29195179
DOI: 10.1016/j.jcis.2017.11.059

Abstract

A facile chemoselective one-pot strategy for the deprotection of oxime has been developed using Fe⁰-polyaniline composite nanofiber (Fe⁰-PANI), as a catalyst. Nano material based Fe⁰-PANI catalyst has been synthesized via in-situ polymerization of ANI monomer and followed by reductive deposition of Fe⁰ onto PANI matrix. The catalyst was characterized by FE-SEM, HR-TEM, BET, XRD, ATR-FTIR, XPS and VSM techniques. The scope of the transformation was studied for aryl, alkyl and heteroarylketoxime with excellent chemoselectivity (>99%). Mechanistic investigations suggested the involvement of a cationic intermediate with Fe³⁺ active catalytic species. Substituent effect showed a linear free energy relationship. The activation energy (E_a) was calculated to be 17.46 kJ mol^-1 for acetophenone oxime to acetophenone conversion. The recyclability of the catalyst demonstrated up to 10 cycles without any significant loss of efficiency. Based on the preliminary experiments a plausible mechanism has been proposed involving a carbocationic intermediate.

Keywords: Chemoselective; Composite; Hydrolysis; Nanofiber; Oxime; Polyaniline.