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用光谱法研究了异戊二烯顺-1,4聚合催化体系 Ln(napb)_3-Al(i_C_4H_9) _3-Al_2(C_2H_5) _3Cl_3中稀土离子的价态.结果表明,在上述催化体系中,镨,钕,钆,铒部以三价形式存在,这说明上述稀土化合物催化活性的不同,不是因为价态有所差异.对不同条件下含 Nd(naph)_3的催化剂溶液的光谱及聚合活性研究结果表明,催化活性与 Nd~(+3) 的特征吸收强度有关,吸收强度愈强,活性愈高.提高铝/钕克分子比及延长催化剂陈化时间,都导致特征吸收强度及催化活性的增大.
The valences of rare earth ions in Ln (napb) _3-Al (i_C_4H_9) _3-Al_2 (C_2H_5) _3Cl_3 of isoprene cis-1,4 polymerization system were investigated by spectroscopy.The results showed that in the above catalytic system, Praseodymium, neodymium, gadolinium and erbium exist in the trivalent form, indicating that the difference in catalytic activity of the above rare earth compounds is not due to differences in valence states. The spectral and polymerization activities of the catalyst solution containing Nd (naph) 3 under different conditions The results show that the catalytic activity is related to the characteristic absorption intensity of Nd ~ (+3), and the stronger the absorption intensity is, the higher the activity is. Increasing the mole ratio of aluminum to neodymium and prolonging the aging time of the catalyst lead to the characteristic absorption and catalytic activity Increase.