Catalysts for Preparing Ultra High Molecular Weight Polyethylene (UHMWPE)

Ultra high molecular weight polyethylene obtained according to a process comprising:

• a) injecting a catalyst system into a reactor, wherein the catalyst system comprises a metallic complex and an activating agent selected from aluminium alkyl, boron containing compounds, or aluminoxane, wherein the metallic complex is of formula VII
• wherein R1, R3, R4, R5, R6 and R7 are each independently selected from hydrogen, alkyl, cycloalkyl or aryl group comprising from 1 to 12 carbon atoms, a halogen, or a silyl group, wherein two or more of said groups can be linked together to form one or more rings;
• wherein Q is an atom selected from Group 16;
• wherein A is an atom selected from Group 15;
• wherein R2 is independently selected from an unsubstituted or substituted aryl or cycloalkyl group having from 1 to 12 carbon atoms, or from Z(R9)3 wherein Z is an atom selected from Group 14 of the Periodic Table and each R9 is independently selected from a hydrogen, substituted or unsubstituted aryl, alkyl or cycloalkyl group having from 1 to 12 carbon atoms, with the restriction that R2 is a bulky group, at least as sterically bulky as tert-butyl;
• wherein R8 is an unsubstituted or substituted aryl, alkyl or cycloalkyl group having from 1 to 12 carbon atoms;
• wherein M is a metal Group 4 of the Periodic Table;
• and
• wherein each X is the same or different and is a halogen atom, a substituted or unsubstituted alkyl, cycloalkyl or aryl group comprising from 1 to 12 carbon atoms, an amido group, or an alkoxide group;
• b) injecting olefin monomers either before, after, or simultaneously with step a), wherein the olefin monomers comprise ethylene;
• c) maintaining the reactor under polymerisation conditions;
• and
• d) retrieving the ultra high molecular weight polyethylene, wherein the catalyst concentration is sufficiently low to retrieve the ultra high molecular weight polyethylene having an intrinsic viscosity of at least 7.5 dL/g measured according to ASTM D2857, and wherein the ultra high molecular weight polyethylene has a polydispersity index ranging from 1 to 5.

A process for preparing a bi-dentate pro-ligand comprising:

• providing a 2-methoxynaphthalene of formula II:
• reacting the 2-methoxynaphthalene of formula II with R2X′ in the presence of a first base, wherein X′ is a leaving group, to obtain a compound of formula III:
• reacting the compound of formula III with an electrophilic bromine source to obtain a compound of formula IV:
• reacting the compound of formula IV with acylchloride R1COCl in the presence of a second base to obtain a compound of formula V′:
• wherein R1 is an unsubstituted or substituted aryl, alkyl, or cycloalkyl group comprising from 1 to 12 carbon atoms, a halogen, or a silyl group;
• deprotecting the compound of formula III in order to obtain a compound of formula VI:
• condensation of the compound of formula VI with an amine R8—NH2 in the presence of catalytic amounts of an acid, optionally in the presence of tetraethyl orthosilicate or titanium tetrachloride, to obtain compounds of formula I and its tautomeric form I′, being a bidentate pro-ligand:
• wherein A is nitrogen and Q is oxygen.