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Synthesis of less acidic VO-salen complex grafted onto graphene oxide via functionalization of surface carboxyl groups for the selective oxidation of norbornene

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Abstract

Oxidation of norbornene was carried out over oxovanadium Schiff base complex grafted on –OH and –COOH modified graphene oxide (GO) as heterogeneous catalysts using 30% H2O2 as an oxidant and ethylene glycol as a solvent. Amongst them, the carboxylic acid group modified GO was found to be better for this transformation. The lower conversion with –OH modified catalyst was ascribed to the higher acidic nature of the catalyst. NH3-TPD study confirmed the less acidic sites on the –COOH modified catalyst and this less acidic nature and controlled addition of 30% H2O2 became the centre of action for this catalytic transformation. Absolute conversion of norbornene (100%) with 98.8% 2,3-epoxy norbornane was achieved at 60 °C in 1 h. This catalyst was recycled four times without significant loss of activity. This durability of the catalyst was believed to be due to strong π–π stacking interaction of GO sheet and an unsaturated ring of ligand and cyclic structure of ligand which protect the metal to leach out.

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Acknowledgements

We express our gratitude to the Head, Applied Chemistry Department, Faculty of Technology & Engineering, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India for providing the necessary laboratory facilities. Authors are thankful to the DST-PURSE program for providing Raman measurements. Authors are also highly thankful to UGC-DAE Consortium for Scientific Research, Indore, India and Raja Ramanna Centre for Advanced Technology, Indore, India for providing HRTEM and XPS facilities.

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Authors and Affiliations

  1. Applied Chemistry Department, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390 001, India

    Ravi S. Vithalani, Dikin Patel & Chetan K. Modi

  2. Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390 002, India

    Prafulla K. Jha

  3. Synchrotrons Utilisation Section, Raja Ramanna Centre for Advanced Technology, Indore, 452013, India

    Himanshu Srivastava & Sanjeev R. Kane

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  1. Ravi S. Vithalani
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Vithalani, R.S., Patel, D., Modi, C.K. et al. Synthesis of less acidic VO-salen complex grafted onto graphene oxide via functionalization of surface carboxyl groups for the selective oxidation of norbornene. Graphene Technol 5, 83–101 (2020). https://doi.org/10.1007/s41127-020-00037-x

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