Kam insky型催化剂催化乙烯齐聚──二酚基二茂锆的催化作用

Oligomerization of Ethylene Catalyzed by Kaminsky\|Type Catalysts Catalysis of Diaryloxyzirconocene

通过改变 Ａｌ／ Ｚｒ 比、反应温度及反应时间， 分别考察了 Ｃｐ２ Ｚｒ（ Ｏ Ａｒ）２／ Ｅ Ａ Ｏ （ Ａｒ＝ Ｃ６ Ｈ５、ｐ  Ｃ６ Ｈ４ Ｍ ｅ、ｍ  Ｃ６ Ｈ４ Ｎ Ｏ２、ｐ  Ｃ６ Ｈ４ Ｎ Ｏ２） ４ 种体系对乙烯齐聚的催化作用． 发现用 Ｃｐ２ Ｚｒ（ Ｏ Ａｒ）２ 代替 Ｃｐ２ Ｚｒ Ｃｌ２ 作为主催化剂， 对于 Ｋａｍ ｉｎｓｋｙ 型体系 Ｃｐ２ Ｚｒ Ｌ２／ Ｅ Ａ Ｏ 催化乙烯齐聚， 具有调变作用，在提高催化活性的同时， 可使低碳烯烃的选择性明显改善． 在 Ｃｐ２ Ｚｒ（ Ｏ Ａｒ）２／ Ｅ Ａ Ｏ 的４ 种催化体系中， 当酚基对位带有强吸电子基团时（ Ａｒ＝ ｐ  Ｃ６ Ｈ４ Ｎ Ｏ２）， 对乙烯齐聚的催化性能最佳．

Four diaryloxyzirconocene complexes : Cp 2Zr(OC 6H 5) 2(Ⅰ), Cp 2Zr(OC 6H 4Me\|p) 2(Ⅱ), Cp 2Zr(OC 6H 4NO 2\|m) 2(Ⅲ) and Cp 2Zr(OC 6H 4NO 2\|p) 2(Ⅳ) have been synthesized. The catalytic behaviors of the bicomponent systems Cp 2Zr(OAr) 2/EAO (ethylaluminoxane) for ethylene oligomerization have been investigated. All of the four catalytic systems display higher acitvity and better selectivity of C 4～8 olefins than Kaminsky catalyst Cp 2ZrCl 2/EAO . Among Cp 2Zr(OAr) 2/EAO systems, the one in which two strong electron\|withdrawing phenolic groups (p\|OC 6H 4NO 2) coordinate to the Zr center is preferable to other Kaminsky\|type catalysts for homogeneous oligomerization of ethylene.