Addition reaction of 1,6-diiodoperfluorohexane with ethylene: Process optimization and kinetic study

The fluorine-containing compound with symmetrical structure (I-C 2 H 4 -(CF 2 ) n -C 2 H 4 -I) is a widely used the intermediate of fluorine-containing copolymer having various applications in the organic fluorine chemical industry. Herein, the addition reaction of 1,6-diiodoperfluorohexane (I-C 6 F 12 -I) with ethylene was studied at different temperatures (130 to 170 °C), reaction time (4 to 12 h), solvents (acetonitrile, DMF, Py, n-hexane) and initiators (AIBN, DTBP, CuI, CuCl). The yield of the product (I-C 2 H 4 C 6 F 12 C 2 H 4 -I) was up to 73 % under optimal reaction conditions (150 °C, 10 h, CuI, acetonitrile). The kinetic equation of the reaction was derived through further studies on the reaction kinetics. The addition reaction is a consecutive reaction, the reaction order and the activation energy of the first step (I-C 6 F 12 -I to I-C 6 F 12 C 2 H 4 -I) are 1.131 and 56.53 kJ mol -1 , and the reaction order and the activation energy of the second step (I-C 6 F 12 C 2 H 4 -I to I-C 2 H 4 C 6 F 12 C 2 H 4 -I) are 0.479 and 49.81 kJ mol -1 . These are important results that allows for further process intensification and designing of reactor.