Thermoregulated Ionic Liquid Biphasic System And The Application In The Hydrogenation Of Olefins

A thermoregulated ionic liquid biphasic system was developed by using polyether modified quarternary ammonium salts ionic liquid and organic solvents. This ionic liquid biphasic system possesses a thermoregulated property i.e. "mono-phase under high temperature, bi-phase under room temperature". The hydrogenation of 1-dodecene, diisobutylene and SBS (Styrene-Butadiene-Styrene copolymer) catalyzed by Ru /TPPTS complex have been studied in this new system respectively. The reaction conditions have been optimized and the recycle efficiency and the leaching of the catalyst have been studied. In the hydrogenation of 1-dodecene the yield of n-dodecane reached 98% under the optimized reaction conditions. After reaction, the catalyst retained in ionic liquid can be easily recovered by phase separation at room temperature. The catalyst has been recycled for 10 times without obvious decrease of the catalytic activity. The average leaching of Ru in organic phase is about 0.2%. In the hydrogenation of diisobutylene the yield of product is about 80% and the catalyst can be recycled 10 times with a little decrease of the catalytic activity after the fifth run. There was not leaching of Ru in the organic phase detected by ICP-AES analysis. The hydrogenation degree of SBS reached about 60% in the THF/H₂O/ionic liquid system and the catalyst could be reused for three times. The hydrogenation degree of SBS in the toluene/cyclohexane/ionic liquid system was only 25% although the system was homogeneous at reaction temperature and came back to biphasic at room temperature. Hydrogenation of SBS in this ionic liquid system needs further research.