Nickel-catalyzed polymerization of ethylene

Polymerization process for producing substantially linear and crystalline polyethylene having a molecular weight of at least 1000, said process comprising contacting and reacting ethylene, in an oxygen-free atmosphere, at a temperature in the range of about 0.degree. C. to about 200.degree. C., in the presence of a nickel-containing catalyst selected from:

• 1(a) The dinickel compound of the formula ##STR23## wherein:
• R.sup.3 and each R.sup.4, independently, is H or C.sub.1-20 hydrocarbyl;
• X.sup.1 is O or S;
• E.sup.1 is P, As or Sb;
• and each of R.sup.5 and R.sup.6, independently, is H, C.sub.1-20 hydrocarbyl or a functional group selected from --OR.sup.2, --Cl, --CO.sub.2 R.sup.2, --CO.sub.2 M, --C(O)N(R.sup.1).sub.2, --C(O)R.sup.2, --SR.sup.2, --SO.sub.2 R.sup.2, --OSO.sub.2 R.sup.2, --SOR.sup.2, --P(O)(OR.sup.2).sub.2-y (R.sup.1)y, --CN, --NHR.sup.2, --N(R.sup.2).sub.2, ##STR24## --Si(OR.sup.1).sub.3-x (R.sup.1).sub.x, --OSi(OR.sup.1).sub.3-x (R.sup.1).sub.x, --NO.sub.2, --SO.sub.3 M, --PO.sub.3 M.sub.2 and --P(O)(OR.sup.2).sub.2 M
• wherein M is alkali or alkaline earth metal, ammonium, quaternary ammonium, phosphonium or arsonium, y is 0, 1 or 2, each R.sup.1, independently, is H or C.sub.1-20 hydrocarbyl, each R.sup.2, independently, is C.sub.1-20 hydrocarbyl, and x is 0 or an integer of 1 to 3, or R.sup.5 and R.sup.6, taken together, is a substituted or unsubstituted C.sub.5-8 alicyclic, C.sub.5-8 heterocyclic or C.sub.6-14 aromatic ring, the heteroatom of the heterocyclic ring being selected from O, N and S;
• 1(B) the nickel compound of the formula ##STR25## wherein:
• R.sup.3, R.sup.4, R.sup.5, R.sup.6, X.sup.1 and E.sup.1 are defined as above and L.sup.1 is a weakly coordinating ligand, or R.sup.3 and L.sup.1 taken together is ##STR26## wherein R" is H, C.sub.1-20 hydrocarbyl or oxyhydrocarbyl or n(R.sup.2).sub.2 wherein R.sup.2 is defined as above:
• 1(c) the nickel-containing compound of the formula ##STR27## wherein:
• R.sup.1, R.sup.4, R.sup.5, R.sup.6, X.sup.1 and E.sup.1 are defined as above;
• each R.sup.7, independently, is H, --OSi(R"').sub.3, C.sub.1-20 alkyl or oxyalkyl, C.sub.6-20 aryl, alkaryl, aralkyl or oxyaryl, N(R.sup.2).sub.2 wherein R.sup.2 is as defined above, or halogen, or both R.sup.7 groups, taken together, is a 5 to 8-membered heterocyclic ring wherein the heteroatom is selected from 0, N and S;
• and
• each R"', independently, is C.sub.1-20 alkyl or oxyalkyl, C.sub.6-20 aryl, alkaryl,. aralkyl or oxyaryl;
• (2) the mixture comprising:
• (i) the nickel compound of the formula ##STR28## wherein:
• R.sup.3, R.sup.4, R.sup.5, R.sup.6, X.sup.1 and E.sup.1 are defined as above and L.sup.2 is a strongly coordinating ligand;
• and
• (ii) an acceptor compound which can react irreversibly with L.sup.2 ;
• and
• (3) the mixture comprising:
• (i) the nickel compound of the formula ##STR29## wherein:
• R.sup.4, R.sup.5, R.sup.6, X.sup.1 and E.sup.1 are defined as above;
• and
• (ii) a suitable alkylating or arylating compound.