Process for producing polyethylene

A process for polymerizing ethylene and/or ethylene and at least one or more other olefin(s) comprising contacting, under polymerization conditions, the ethylene and/or ethylene and at least one or more other olefin(s) with a Ziegler-Natta catalyst containing at least one or more internal electron donor, wherein the internal electron donor is present in an amount represented by a molar ratio of internal electron donor to transition metal compound of the Ziegler-Natta catalyst of from 1:1 to about 1000:1, trimethylaluminum and at least one or more external electron donor compound containing at least one carbon-oxygen-carbon linkage (C—O—C) selected from the group consisting of Formula 1,

• R1—CH2—O—CH2—R2,
• Formula 2,
• R3—O—R4,
• Formula 3,
• R5—O—R6,
• and Formula 4,
• R7—O(—R8—O)n—R9,
• where n ranges from 1 to 30,
• R1 and R2 are independently selected from the group consisting of hydrogen, saturated and unsaturated aliphatic groups containing from 1 to 30 carbon atoms and from 0 to 30 hetroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements, and substituted and unsubstituted aromatic groups containing from 1 to 30 carbon atoms and from 0 to 30 heteratoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements,
• R3 and R4 are linked and form part of a cyclic or polycyclic structure and are hydrocarbons independently selected from the group consisting of saturated and unsaturated aliphatic groups containing from 1 to 30 carbon atoms and from 0 to 30 heteroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements, and substituted and unsubstituted aromatic groups containing from 1 to 30 carbon atoms and from 0 to 30 heteroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements,
• R5 is selected from the group consisting of substituted and unsubstituted aromatic groups containing from 1 to 30 carbon atoms and from 0 to 30 heteroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements, and
• R6, R7, R8 and R9 are independently selected from the group consisting of saturated and unsaturated aliphatic groups containing from 1 to 30 carbon atoms and from 0 to 30 heteroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements, and substituted and unsubstituted aromatic groups containing from 1 to 30 carbon atoms and from 0 to 30 heteroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of the Elements.