Cationic copolymerization of tetrahydrofuran with propylene oxide. V. Effect of diol cocatalyst structure and concentration with antimony pentachloride as catalyst

✍ Scribed by Alvarez, E. J. ;Hornof, V. ;Blanchard, L. P.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1972
• Tongue: English
• Weight: 421 KB
• Volume: 10
• Category: Article
• ISSN: 0449-296X
• DOI: 10.1002/pol.1972.150100804

✦ Synopsis

Abstract

The effects of the chemical nature and the concentration of diol cocatalysts in the copolymerization of propylene oxide (PO) and tetrahydrofuran (THF) catalyzed by antimony pentachloride were studied. The least bulky diol, 1,2‐ethanediol, was found to be the most active species, judging from the highest rate of copolymerization. The variation of rate was much smaller with the other diols used. Furthermore, the position of the hydroxyl groups did not have much effect on the rate. The concentration of cocatalyst strongly influenced the rate of consumption of both monomers. This is explained by the effect of diol concentration on the equilibrium that exists between the catalyst and the cocatalyst on one side, and the active oxonium complex on the other. The mechanism of cocatalytic effects is discussed in terms of newer concepts of ionic polymerization. Specific solvation of ion‐pairs is visualized as partly responsible for the overall effect of the cocatalysts. Water in quantities commeasurable with those of the cocatalyst was found to retard the reaction. It also gave rise to oligomeric products, as evidenced by gel‐permeation chromatography.