Magnetic Fe3O4@MgAl–LDH composite grafted with cobalt phthalocyanine as an efficient heterogeneous catalyst for the oxidation of mercaptans

• Magnetically separable layered double hydroxide composite.
• Heterogeneous cobalt phthalocyanine catalyst for oxidation of mercaptans under alkali free conditions.
• Facile recovery of the catalyst by using external magnet and efficient recycling without change in catalytic activity.
• Efficient conversion and higher product yields.
• Improved methodology for sweetening of petroleum products.

Magnetically separable layered double hydroxide MgAl–LDH@Fe3O4 composite supported cobalt phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl–LDH@Fe3O4 support prevents the leaching of the catalyst and improves its activity and stability.

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