Alkoxy magnesium supported olefin polymerization catalyst component, catalyst and application thereof

An alkoxymagnesium supported olefin polymerization catalyst component, comprising the reaction products of the following components:

• 1) an alkoxymagnesium compound represented by the formula Mg(OR1′)N(OR2′)2-N, wherein R1′ and R2′ may be the same or different and are C1-C20 alkyl group, 0≤N≤2;
• 2) at least one titanium compound represented by the formula Ti(OR)nX4-n, wherein R represents a C1-C4 alkyl group;
• X represents chlorine, bromine or iodine atom;
• 0≤n≤4;
• 3) at least one electron donor a compound and at least one electron donor b compound;
• wherein the electron donor a compound is selected from the ortho-phenylene diester of the formula (I):
• wherein RI and RII are the same or different substituted or unsubstituted linear or branched C1-C20 alkyl group, C3-C20 cycloalkyl group, C6-C20 substituted or unsubstituted aryl group, C7-C20 substituted or unsubstituted aralkyl group, C2-C10 olefin group, C10-C20 fused ring aryl group or ester group, neither RI or RII is hydrogen;
• R1-R4 are the same or different and are selected from the group consisting of hydrogen, substituted or unsubstituted C1-C20 hydrocarbyl group, C1-C20 alkoxy group, heteroatom, and combination thereof.
• wherein the electron donor b compound is selected from the group consisting of diethers of the formula (II):
• wherein R, R1, R2, R3, R4 and R5 may be the same or different and represent H or linear or branched alkyl, cycloalkyl, aryl, alkaryl or aralkyl group having 1 to 18 carbon atoms;
• R6 and R7 may be the same or different and represent linear or branched C1-C20 alkyl group, C3-C20 cycloalkyl group, C5-C20 aryl group, C7-C20 alkaryl and C7-C20 aralkyl group;
• one or more groups of R, R1 to R7 may be linked to form a cyclic structure, each of which may comprise one or more heteroatom selected from the group consisting of halogen, N, O, S, P, and Si;
• wherein the molar ratio of the electron donor a compound to the electron donor b compound is from 0.05 to 20.