Polymerization. IX. Metalation during Alfin Polymerization of Butadiene and the Formation of Gel

The preparation and properties of polybutadiene (jumping rubber)

“…The alfin catalyst used in this demonstration is a solid surface catalyst developed by A. A. Morton (1,2,3) and co-workers at M.I.T. It is produced by reacting amyl chloride with sodium, which is then reacted with isopropyl alcohol.…”

Alfin Catalysts and the Polymerization of Butadiene

“…If, therefore, the ion aggregate is a mixture in which only a part of the organosodium reagent is properly combined or disposed for catalytic activity, the remainder will exert higher metalating activity than the catalyst fraction, and the percentage of gel in the polymer will be correspondingly higher. In practice (Table VII), the amount of gel in the polybutadiene is higher with low alkoxide content and becomes less as the percentage of isopropoxide increases (13,30). The intrinsic viscosity is approximately constant.…”

“…All reactions with the reactive organosodium salts can occur on the surface of the aggregate, from which no pair of ions, much less a single one, need escape to react in solution. This idea is supported by three facts: The medium, pentane, is the poorest solvent known for ionic compounds, no solution of the reagent has ever been detected, and the amount of polymer approximately doubles and triples as the catalyst is proportionately increased (30), whereas no increase should have resulted in a solution already saturated by the reagent.…”

Effect of Associated Salts on the Polymerization of Butadiene by Organosodium Reagents

“…The preparation of an alfin catalyst from 1 gram atom of sodium, 0.5 mole of amyl chloride, 0.35 mole of 2-propanol, and propylene was carried out in the usual way (17,18,20) for method B, except that in a series of preparations the 2-propanol was replaced by mixtures of allyl alcohol and 2-propanol. Each catalyst mixture was then tested for its activity toward butadiene and a portion was also carbonated in order to determine the content of unsaturated carboxylic acid that was expected to be vinylacetic acid.…”