Initiator/TiCl4 initiated cationic polymerization of pyrolysis gasoline distillate

Abstract

In initiator/TiCl₄-initiated cationic polymerization, studies of the dynamics of reaction systems must be conducted within a certain range of the concentration ratio between the initiator and TiCl₄. The current study explored the range of the concentration ratio of CH₂Cl₂/TiCl₄ in the cationic polymerization of pyrolysis gasoline. AlCl₃ and TiCl₄ were used as the catalysts. The compositions and iodine values of the light components were analyzed using gas chromatography-mass spectrometry and the iodine–alcohol method, respectively. The molecular weights of the resulting polymers were analyzed using gel permeation chromatography, and their compositions were analyzed using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. In the CH₂Cl₂/TiCl₄-initiated cationic polymerization of multiple-olefin-containing C₉ pyrolysis distillate, the CH₂Cl₂/TiCl₄ ratio needed to be ≤1 for effective initiation. A low concentration of olefins in the reaction systems yielded satisfactory polymerization. The temperature for the CH₂Cl₂/TiCl₄-initiated polymerization of the C₉ pyrolysis distillate was 50 °C, and the amount of TiCl₄ was 1.5%. The olefins in the C₉ pyrolysis distillate were effectively isolated from the saturated solutions through cationic polymerization, and the resulting light oil was transparent and colorless. The analysis of the resulting polymers suggested the secondary polymerization of low-molecular-weight polymers after the addition of initiator/TiCl₄.