Polymerization processes and polymers formed therefrom are described herein. Such processes generally include providing a catalyst system, introducing the catalyst system to a reaction zone, introducing 1-chlorobutane to the reaction zone, introducing an olefin monomer to the reaction zone, contacting the olefin monomer with the catalyst system in the presence of the 1-chlorobutane to form a polyolefin and withdrawing the polyolefin from the reaction zone. The catalyst system is generally formed from a process including contacting a magnesium dialkoxide compound with a first agent to form a first compound, contacting the first compound with a plurality of halogenating/titanating agents to form a reaction product and contacting the reaction product with an activating agent to form the catalyst system.