(181bh) The Epoxidation of Polybutadiene By Reaction-Controlled Phase-Transfer Catalyst

The epoxidation of polybutadiene (PBD) can not only give polarity to the polymer, but also provide active sites for its further modification. However, the usual way of epoxidizing PBD is using organic peroxide acid which is not economical and environmentally friendly. And the epoxidized polybutadiene (EPB) is not easily purified.

In our recent work, PBD was epoxidized quantitatively, efficiently and selectively by H₂O₂ combined with the reaction-controlled phase-transfer catalyst which could be recycled effectively. The influences of the catalyst dosage, solvent, temperature and reaction time on the epoxidation of PBD were studied in detail. The kinetic studies confirmed that the reaction in the liquid-liquid system was pseudo first-order. The raw material of PBD can be either the commercial block rubber or the polymer in original solution from polymerization reactor. When using the original solution of PBD, the recovery ratio of catalyst would be up to 92.7 wt%, solvent can be used less, time and energy consuming processes, such as the condensation, washing, drying and briquetting in preparation of PBD solid rubber in the polymerization workshop, and the cutting, dissolving of solid rubber in preparation of EPB, could be removed. Furthermore, the epoxy ratio of EPB could be controlled quantitatively in the range of 0-20 mol% through changing the amount of H₂O₂ added. The recycle text indicated that the activity of catalyst was still kept in high compared with the fresh one. This method of epoxidizing PBD was promising for industry and was potentially applied to the epoxidation of other polymers with double bonds.