苯乙烯-异戊二烯-苯乙烯(SIS)嵌段共聚物的镍系催化加氢

Hydrogenation of styrene-isoprene-styrene block copolymer with nickel catalyst

Ni(naph) 2 /Al(i-Bu) 3 常温、常压催化SIS加氢的研究结果表明 ,反应只发生在PIp中的不饱和双键上 ,苯环不参与加氢反应 ;实验条件下 ,PIp中的 3,4-链节、1,4-链节具有相同的加氢活性 ;在 5 0℃、0 .1MPa氢压、1.90× 10 -4 mol/g·SIS的Ni用量、Al与Ni的摩尔比为 5时 ,SIS的加氢度可达92 .6 %;陈化后的催化剂显示出较高的加氢活性。

The hydrogenation of styrene-isoprene-styrene block copolymer(SIS) has been investigated with Ni(naph) 2/Al(i-Bu) 3 catalyst system under lab's conditions:P(H 2)=0.1MPa ,T=50℃ and lower concentration of 1.90×10 -4 mol/g.SIS .The results show that the hydrogenation for SIS is characteristic of very high activity and high selectivity,i.e., phenyl is not hydrogenated,and 3,4-/1,4-chain units of isoprene appear as the same hydrogenation activity . Aging step of preparing the nickel catalyst system is helpful to increase the hydrogenation activity.Suitable molar ratio of Al/Ni is found from 2 to 6 .The degree of hydrogenation could reach about 92.6% as Al/Ni=5.It might be supposed that the catalytic active centers consist of Ni 1+ and Ni 0,furthermore, a synergism between Ni 1+ and Ni 0 could be existence during the hydrogenation process.