An ethylene oligomerization catalyst which contains a bridged diphosphine ligand having the formula (R1)m(X1)nP1-bridge-P2(R2)X2 wherein R1 and R2 are independently selected from the group consisting of hydrocarbyl and heterohydrocarbyl; X1 is selected from the group consisting of halogen, hydrocarbyl and heterohydrocarbyl; m is 1 or 2; n is 0 or 1; m + n = 2; bridge is a divalent bridging group bonded to P1 and P2; and X2 is halogen. The present ligands differ from prior diphosphine ligands used in olefin oligomerization processes in that at least one halide substituent is directly bonded to at least one P atom of the ligand. The behavior of catalysts that are prepared from a chromium salt and the present ligands is unusual and surprising. A ligand of this invention with a single F substituent and three phenyl substituents may be used to prepare a selective tetramerization catalyst which produces an oligomerization product having an octene selectivity of about 35 weight %. The replacement of the single F atom with a single CI atom can increase the octene selectivity to about 70-75 weight %.
一种
乙烯寡聚催化剂,其含有一个桥式二
膦配体,其
化学式为(R1)m(X1)nP1-bridge-P2(R2)X2,其中R1和R2独立地选自羟基烷基和杂环羟基烷基组成的群;X1选自卤素、羟基烷基和杂环羟基烷基组成的群;m为1或2;n为0或1;m + n = 2;bridge是与P1和P2键合的二价桥接基团;X2为卤素。本
配体与用于烯烃寡聚化过程的先前二
膦配体不同之处在于至少一个卤代取代基直接键合到
配体的至少一个P原子上。由
铬盐和本
配体制备的催化剂的行为是不同寻常和令人惊讶的。具有单个F取代基和三个苯基取代基的本发明
配体可用于制备选择性四聚化催化剂,该催化剂产生具有约35重量%
辛烯选择性的寡聚物产品。用单个CI原子替换单个F原子可以将
辛烯选择性提高到约70-75重量%。