A new synthetic approach to oxidation organocatalysts supported on Merrifield resin using plasma-enhanced chemical vapor deposition

• New catalyst was prepared with plasma enhanced-chemical vapor deposition technique.
• The catalyst is selective for epoxidation in organic/water media.
• This “non-conventional synthesis” is eco-sustainable and inexpensive.

Described here is the first application of plasma-enhanced chemical vapor deposition (PE-CVD) to the synthesis of catalytically active materials, prepared by covering Merrifield resin beads with an oxygen-containing fluorocarbon thin film deposited in a hexafluoropropene-O2 plasma. Such modified resins catalyze both the selective epoxidation of trans-β-methylstyrene and its double oxidative cleavage to benzaldeyde in organic–water biphasic media at room temperature, using potassium monoperoxysulfate (KHSO5) as the terminal oxidant. Interestingly, the epoxide/benzaldehyde product ratio strictly depends on the conditions adopted for catalyst generation. This, coupled with evidence for the presence of carbonyl groups on the surface of treated resins, point to dioxirane and singlet oxygen (1O2)-mediated oxidations; 1O2 being produced in the decomposition of KHSO5. Compared to traditional synthetic procedures to obtain similar catalytic active materials, the application of PE-CVD is eco-sustainable and less expensive. Also, the activity of catalysts can be fully restored upon iterative re-treatment of the exhausted resin.

Figure optionsDownload high-quality image (134 K)Download as PowerPoint slide