Experimental investigation of the reaction of HCFC-22 and methane in a dielectric barrier discharge non-equilibrium plasma

• The treatment of strong greenhouse gas HCFC-22 was studied.
• A dielectric barrier discharge non-equilibrium plasma was applied.
• The conversion of HCFC-22 yielded non-crosslinked and crosslinked fluoropolymers.
• The synthesised non-crosslinked polymers are random co-polymers.

A dielectric barrier discharge non-equilibrium plasma was employed to study the reaction of HCFC-22 (CHClF2) with methane (in an argon bath gas) at atmospheric pressure and in the absence of oxygen and nitrogen. The reaction produced a fluorine-containing polymeric product, as well as gaseous species including H2, HF, HCl, CHF3, C2H3F, CH3Cl, CH2ClF, C2HClF4, CHCl2F, CH2Cl2 and CCl2F2. While the main polymeric fraction is non-crosslinked, a small portion of the solid product is crosslinked. The polymers contain a wide range of functional groups including CH3, CH2, CHCl, CHF, CHClF, CHF2, CF2 and CF3. The conversion level of CHClF2 increased from 53% to 78%, with an increment in input energy density from 3 kJ L−1 to 13 kJ L−1. A reaction mechanism is proposed explaining the formation of gaseous as well as polymeric products.